A polygonal anastomosis at the base of the brain formed by the internal carotid (CAROTID ARTERY, INTERNAL), proximal parts of the anterior, middle, and posterior cerebral arteries (ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; POSTERIOR CEREBRAL ARTERY), the anterior communicating artery and the posterior communicating arteries.
The arterial blood vessels supplying the CEREBRUM.
Maintenance of blood flow to an organ despite obstruction of a principal vessel. Blood flow is maintained through small vessels.
Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)
Non-invasive method of vascular imaging and determination of internal anatomy without injection of contrast media or radiation exposure. The technique is used especially in CEREBRAL ANGIOGRAPHY as well as for studies of other vascular structures.
Participation of employees with management as a labor-management team, in decisions pertaining to the operational activities of the organization or industry.
PROCEDURES that use NEUROENDOSCOPES for disease diagnosis and treatment. Neuroendoscopy, generally an integration of the neuroendoscope with a computer-assisted NEURONAVIGATION system, provides guidance in NEUROSURGICAL PROCEDURES.
Branch of the common carotid artery which supplies the anterior part of the brain, the eye and its appendages, the forehead and nose.
The circulation of blood through the BLOOD VESSELS of the BRAIN.
A noninflammatory, progressive occlusion of the intracranial CAROTID ARTERIES and the formation of netlike collateral arteries arising from the CIRCLE OF WILLIS. Cerebral angiogram shows the puff-of-smoke (moyamoya) collaterals at the base of the brain. It is characterized by endothelial HYPERPLASIA and FIBROSIS with thickening of arterial walls. This disease primarily affects children but can also occur in adults.
Radiography of the vascular system of the brain after injection of a contrast medium.
Changes in the observed frequency of waves (as sound, light, or radio waves) due to the relative motion of source and observer. The effect was named for the 19th century Austrian physicist Johann Christian Doppler.
A method of delineating blood vessels by subtracting a tissue background image from an image of tissue plus intravascular contrast material that attenuates the X-ray photons. The background image is determined from a digitized image taken a few moments before injection of the contrast material. The resulting angiogram is a high-contrast image of the vessel. This subtraction technique allows extraction of a high-intensity signal from the superimposed background information. The image is thus the result of the differential absorption of X-rays by different tissues.
Vascular diseases characterized by thickening and hardening of the walls of ARTERIES inside the SKULL. There are three subtypes: (1) atherosclerosis with fatty deposits in the ARTERIAL INTIMA; (2) Monckeberg's sclerosis with calcium deposits in the media and (3) arteriolosclerosis involving the small caliber arteries. Clinical signs include HEADACHE; CONFUSION; transient blindness (AMAUROSIS FUGAX); speech impairment; and HEMIPARESIS.
A non-invasive technique using ultrasound for the measurement of cerebrovascular hemodynamics, particularly cerebral blood flow velocity and cerebral collateral flow. With a high-intensity, low-frequency pulse probe, the intracranial arteries may be studied transtemporally, transorbitally, or from below the foramen magnum.
The artery formed by the union of the right and left vertebral arteries; it runs from the lower to the upper border of the pons, where it bifurcates into the two posterior cerebral arteries.
Time period from 1601 through 1700 of the common era.
The first branch of the SUBCLAVIAN ARTERY with distribution to muscles of the NECK; VERTEBRAE; SPINAL CORD; CEREBELLUM; and interior of the CEREBRUM.
Abnormal outpouching in the wall of intracranial blood vessels. Most common are the saccular (berry) aneurysms located at branch points in CIRCLE OF WILLIS at the base of the brain. Vessel rupture results in SUBARACHNOID HEMORRHAGE or INTRACRANIAL HEMORRHAGES. Giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the OCULOMOTOR NERVE. (From Adams et al., Principles of Neurology, 6th ed, p841)
An irregular unpaired bone situated at the SKULL BASE and wedged between the frontal, temporal, and occipital bones (FRONTAL BONE; TEMPORAL BONE; OCCIPITAL BONE). Sphenoid bone consists of a median body and three pairs of processes resembling a bat with spread wings. The body is hollowed out in its inferior to form two large cavities (SPHENOID SINUS).
Narrowing or stricture of any part of the CAROTID ARTERIES, most often due to atherosclerotic plaque formation. Ulcerations may form in atherosclerotic plaques and induce THROMBUS formation. Platelet or cholesterol emboli may arise from stenotic carotid lesions and induce a TRANSIENT ISCHEMIC ATTACK; CEREBROVASCULAR ACCIDENT; or temporary blindness (AMAUROSIS FUGAX). (From Adams et al., Principles of Neurology, 6th ed, pp 822-3)
Branch of the common carotid artery which supplies the exterior of the head, the face, and the greater part of the neck.
A delicate membrane enveloping the brain and spinal cord. It lies between the PIA MATER and the DURA MATER. It is separated from the pia mater by the subarachnoid cavity which is filled with CEREBROSPINAL FLUID.
Use of reflected ultrasound in the diagnosis of intracranial pathologic processes.
A subtype of migraine disorder, characterized by recurrent attacks of reversible neurological symptoms (aura) that precede or accompany the headache. Aura may include a combination of sensory disturbances, such as blurred VISION; HALLUCINATIONS; VERTIGO; NUMBNESS; and difficulty in concentrating and speaking. Aura is usually followed by features of the COMMON MIGRAINE, such as PHOTOPHOBIA; PHONOPHOBIA; and NAUSEA. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)
Artery originating from the internal carotid artery and distributing to the eye, orbit and adjacent facial structures.
An acquired or spontaneous abnormality in which there is communication between CAVERNOUS SINUS, a venous structure, and the CAROTID ARTERIES. It is often associated with HEAD TRAUMA, specifically basilar skull fractures (SKULL FRACTURE, BASILAR). Clinical signs often include VISION DISORDERS and INTRACRANIAL HYPERTENSION.
Congenital vascular anomalies in the brain characterized by direct communication between an artery and a vein without passing through the CAPILLARIES. The locations and size of the shunts determine the symptoms including HEADACHES; SEIZURES; STROKE; INTRACRANIAL HEMORRHAGES; mass effect; and vascular steal effect.
The infratentorial compartment that contains the CEREBELLUM and BRAIN STEM. It is formed by the posterior third of the superior surface of the body of the sphenoid (SPHENOID BONE), by the occipital, the petrous, and mastoid portions of the TEMPORAL BONE, and the posterior inferior angle of the PARIETAL BONE.
The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
The formation of an area of NECROSIS in the CEREBRUM caused by an insufficiency of arterial or venous blood flow. Infarcts of the cerebrum are generally classified by hemisphere (i.e., left vs. right), lobe (e.g., frontal lobe infarction), arterial distribution (e.g., INFARCTION, ANTERIOR CEREBRAL ARTERY), and etiology (e.g., embolic infarction).
A spectrum of pathological conditions of impaired blood flow in the brain. They can involve vessels (ARTERIES or VEINS) in the CEREBRUM, the CEREBELLUM, and the BRAIN STEM. Major categories include INTRACRANIAL ARTERIOVENOUS MALFORMATIONS; BRAIN ISCHEMIA; CEREBRAL HEMORRHAGE; and others.
The innermost layer of the three meninges covering the brain and spinal cord. It is the fine vascular membrane that lies under the ARACHNOID and the DURA MATER.
Dominance of one cerebral hemisphere over the other in cerebral functions.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.
Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.
Bleeding into the intracranial or spinal SUBARACHNOID SPACE, most resulting from INTRACRANIAL ANEURYSM rupture. It can occur after traumatic injuries (SUBARACHNOID HEMORRHAGE, TRAUMATIC). Clinical features include HEADACHE; NAUSEA; VOMITING, nuchal rigidity, variable neurological deficits and reduced mental status.
A dead body, usually a human body.
Ultrasonography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography is well-suited to identifying the location of high-velocity flow (such as in a stenosis) or of mapping the extent of flow in a certain region.
Pathological processes which result in the partial or complete obstruction of ARTERIES. They are characterized by greatly reduced or absence of blood flow through these vessels. They are also known as arterial insufficiency.
Brief reversible episodes of focal, nonconvulsive ischemic dysfunction of the brain having a duration of less than 24 hours, and usually less than one hour, caused by transient thrombotic or embolic blood vessel occlusion or stenosis. Events may be classified by arterial distribution, temporal pattern, or etiology (e.g., embolic vs. thrombotic). (From Adams et al., Principles of Neurology, 6th ed, pp814-6)
Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.
A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.
Pathological conditions involving the CAROTID ARTERIES, including the common, internal, and external carotid arteries. ATHEROSCLEROSIS and TRAUMA are relatively frequent causes of carotid artery pathology.
A republic in southern Africa, south of ANGOLA and west of BOTSWANA. Its capital is Windhoek.
The process by which a DNA molecule is duplicated.
Tomography using x-ray transmission and a computer algorithm to reconstruct the image.
The tendency to perceive an incomplete pattern or object as complete or whole. This includes the Gestalt Law of Closure.
The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.
The excision of the thickened, atheromatous tunica intima of a carotid artery.
Laboratory techniques that involve the in-vitro synthesis of many copies of DNA or RNA from one original template.
Ordered rearrangement of T-cell variable gene regions coding for the antigen receptors.
Substances used to allow enhanced visualization of tissues.
A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Deoxyribonucleic acid that makes up the genetic material of viruses.
A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.
A technique that labels specific sequences in whole chromosomes by in situ DNA chain elongation or PCR (polymerase chain reaction).
The flow of BLOOD through or around an organ or region of the body.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
Circular duplex DNA isolated from viruses, bacteria and mitochondria in supercoiled or supertwisted form. This superhelical DNA is endowed with free energy. During transcription, the magnitude of RNA initiation is proportional to the DNA superhelicity.
Inhalation anesthesia where the gases exhaled by the patient are rebreathed as some carbon dioxide is simultaneously removed and anesthetic gas and oxygen are added so that no anesthetic escapes into the room. Closed-circuit anesthesia is used especially with explosive anesthetics to prevent fires where electrical sparking from instruments is possible.
A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
The type species of the genus MICROVIRUS. A prototype of the small virulent DNA coliphages, it is composed of a single strand of supercoiled circular DNA, which on infection, is converted to a double-stranded replicative form by a host enzyme.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The sensory discrimination of a pattern shape or outline.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Three groups of arteries found in the eye which supply the iris, pupil, sclera, conjunctiva, and the muscles of the iris.
A system which emphasizes that experience and behavior contain basic patterns and relationships which cannot be reduced to simpler components; that is, the whole is greater than the sum of its parts.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Regulatory sequences important for viral replication that are located on each end of the HIV genome. The LTR includes the HIV ENHANCER, promoter, and other sequences. Specific regions in the LTR include the negative regulatory element (NRE), NF-kappa B binding sites , Sp1 binding sites, TATA BOX, and trans-acting responsive element (TAR). The binding of both cellular and viral proteins to these regions regulates HIV transcription.
"Handwriting is a form of personal script or symbolic representation, primarily used in communication, created by the controlled motion of a writing instrument over a surface, typically performed with the hand and fingers."
The reformation of all, or part of, the native conformation of a nucleic acid molecule after the molecule has undergone denaturation.
CIRCULAR DNA that is interlaced together as links in a chain. It is used as an assay for the activity of DNA TOPOISOMERASES. Catenated DNA is attached loop to loop in contrast to CONCATENATED DNA which is attached end to end.
Disruption of the secondary structure of nucleic acids by heat, extreme pH or chemical treatment. Double strand DNA is "melted" by dissociation of the non-covalent hydrogen bonds and hydrophobic interactions. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible.
Enzymes that catalyze the incorporation of deoxyribonucleotides into a chain of DNA. EC 2.7.7.-.
Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).
A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.
The group of celestial bodies, including the EARTH, orbiting around and gravitationally bound by the sun. It includes eight planets, one minor planet, and 34 natural satellites, more than 1,000 observed comets, and thousands of lesser bodies known as MINOR PLANETS (asteroids) and METEOROIDS. (From Academic American Encyclopedia, 1983)
Enzymes that recombine DNA segments by a process which involves the formation of a synapse between two DNA helices, the cleavage of single strands from each DNA helix and the ligation of a DNA strand from one DNA helix to the other. The resulting DNA structure is called a Holliday junction which can be resolved by DNA REPLICATION or by HOLLIDAY JUNCTION RESOLVASES.
An ascomycetous yeast of the fungal family Saccharomycetaceae, order SACCHAROMYCETALES.
Insertion of viral DNA into host-cell DNA. This includes integration of phage DNA into bacterial DNA; (LYSOGENY); to form a PROPHAGE or integration of retroviral DNA into cellular DNA to form a PROVIRUS.
Antibodies, especially IGE, that bind to tissue of the same species so that ANTIGENS induce release of HISTAMINE and other vasoactive agents. HYPERSENSITIVITY is the clinical manifestation.
The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.
I'm sorry for any confusion, but "Nebraska" is a state located in the central United States and does not have a medical definition. If you have any medical terms or concepts you would like defined, I would be happy to help!
Large bodies consisting of self-luminous gas held together by their own gravity. (From McGraw Hill Dictionary of Scientific and Technical Terms, 6th ed)
The sensory interpretation of the dimensions of objects.
The Arctic Ocean and the lands in it and adjacent to it. It includes Point Barrow, Alaska, most of the Franklin District in Canada, two thirds of Greenland, Svalbard, Franz Josef Land, Lapland, Novaya Zemlya, and Northern Siberia. (Webster's New Geographical Dictionary, 1988, p66)
A group of pathogens comprising the smallest known agents of infectious disease. They are unencapsulated and are capable of replicating autonomously in susceptible cells. Positively identified viroids composed of single-stranded RNA have been isolated from higher plants, but the existence of DNA viroids pathogenic to animals is suspected.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Proteins that catalyze the unwinding of duplex DNA during replication by binding cooperatively to single-stranded regions of DNA or to short regions of duplex DNA that are undergoing transient opening. In addition DNA helicases are DNA-dependent ATPases that harness the free energy of ATP hydrolysis to translocate DNA strands.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.
Poly(deoxyribonucleotide):poly(deoxyribonucleotide)ligases. Enzymes that catalyze the joining of preformed deoxyribonucleotides in phosphodiester linkage during genetic processes during repair of a single-stranded break in duplex DNA. The class includes both EC 6.5.1.1 (ATP) and EC 6.5.1.2 (NAD).
A unique DNA sequence of a replicon at which DNA REPLICATION is initiated and proceeds bidirectionally or unidirectionally. It contains the sites where the first separation of the complementary strands occurs, a primer RNA is synthesized, and the switch from primer RNA to DNA synthesis takes place. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Deoxyribonucleic acid that makes up the genetic material of fungi.
Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.
Viruses whose host is Bacillus. Frequently encountered Bacillus phages include bacteriophage phi 29 and bacteriophage phi 105.
'Hospital Bed Capacity, 500 and over' refers to the maximum number of hospital beds equaling or exceeding 500 that are medically staffed and equipped to provide patient care and accommodation within a healthcare facility.
The biosynthesis of DNA carried out on a template of RNA.
Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.
Waves of oscillating electric and MAGNETIC FIELDS which move at right angles to each other and outward from the source.
Vertical transmission of hereditary characters by DNA from cytoplasmic organelles such as MITOCHONDRIA; CHLOROPLASTS; and PLASTIDS, or from PLASMIDS or viral episomal DNA.
The use of devices which use detector molecules to detect, investigate, or analyze other molecules, macromolecules, molecular aggregates, or organisms.
A genus of parasitic protozoans found in the digestive tract of invertebrates, especially insects. Organisms of this genus have an amastigote and choanomastigote stage in their life cycle.
The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve.
Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.
Group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. It is inherited as an X-linked or autosomal recessive defect. Mutations occurring in many different genes cause human Severe Combined Immunodeficiency (SCID).
##### I'm sorry for any confusion, but "South Dakota" is a state located in the Midwestern region of the United States and it is not a medical term or concept. It does not have a medical definition in a singular sentence or otherwise.
DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.
Macromolecular molds for the synthesis of complementary macromolecules, as in DNA REPLICATION; GENETIC TRANSCRIPTION of DNA to RNA, and GENETIC TRANSLATION of RNA into POLYPEPTIDES.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Electrophoresis in which agar or agarose gel is used as the diffusion medium.
An illusion of vision usually affecting spatial relations.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
Awareness of oneself in relation to time, place and person.
The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.
Viruses whose host is Escherichia coli.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
Nucleotide sequences repeated on both the 5' and 3' ends of a sequence under consideration. For example, the hallmarks of a transposon are that it is flanked by inverted repeats on each end and the inverted repeats are flanked by direct repeats. The Delta element of Ty retrotransposons and LTRs (long terminal repeats) are examples of this concept.
Differential response to different stimuli.
Species- or subspecies-specific DNA (including COMPLEMENTARY DNA; conserved genes, whole chromosomes, or whole genomes) used in hybridization studies in order to identify microorganisms, to measure DNA-DNA homologies, to group subspecies, etc. The DNA probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the DNA probe include the radioisotope labels 32P and 125I and the chemical label biotin. The use of DNA probes provides a specific, sensitive, rapid, and inexpensive replacement for cell culture techniques for diagnosing infections.
DNA TOPOISOMERASES that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. DNA Topoisomerases, Type I enzymes reduce the topological stress in the DNA structure by relaxing the superhelical turns and knotted rings in the DNA helix.
The mallow family of the order Malvales, subclass Dilleniidae, class Magnoliopsida. Members include GOSSYPIUM, okra (ABELMOSCHUS), HIBISCUS, and CACAO. The common names of hollyhock and mallow are used for several genera of Malvaceae.
The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
Proteins conjugated with deoxyribonucleic acids (DNA) or specific DNA.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.
The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.
A tissue preparation technique that involves the injecting of plastic (acrylates) into blood vessels or other hollow viscera and treating the tissue with a caustic substance. This results in a negative copy or a solid replica of the enclosed space of the tissue that is ready for viewing under a scanning electron microscope.
DNA sequences, in cells of the T-lymphocyte lineage, that code for T-cell receptors. The TcR genes are formed by somatic rearrangement (see GENE REARRANGEMENT, T-LYMPHOCYTE and its children) of germline gene segments, and resemble Ig genes in their mechanisms of diversity generation and expression.
Synthetic or natural oligonucleotides used in hybridization studies in order to identify and study specific nucleic acid fragments, e.g., DNA segments near or within a specific gene locus or gene. The probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the probe include the radioisotope labels 32P and 125I and the chemical label biotin.
Water particles that fall from the ATMOSPHERE.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
A site located in the INTRONS at the 5' end of each constant region segment of a immunoglobulin heavy-chain gene where recombination (or rearrangement) occur during IMMUNOGLOBULIN CLASS SWITCHING. Ig switch regions are found on genes encoding all five classes (IMMUNOGLOBULIN ISOTYPES) of IMMUNOGLOBULIN HEAVY CHAINS.
A genus of flagellate protozoa comprising several species that are pathogenic for humans. Organisms of this genus have an amastigote and a promastigote stage in their life cycles. As a result of enzymatic studies this single genus has been divided into two subgenera: Leishmania leishmania and Leishmania viannia. Species within the Leishmania leishmania subgenus include: L. aethiopica, L. arabica, L. donovani, L. enrietti, L. gerbilli, L. hertigi, L. infantum, L. major, L. mexicana, and L. tropica. The following species are those that compose the Leishmania viannia subgenus: L. braziliensis, L. guyanensis, L. lainsoni, L. naiffi, and L. shawi.
Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.
Enzymes that catalyze the release of mononucleotides by the hydrolysis of the terminal bond of deoxyribonucleotide or ribonucleotide chains.
A group of dipyridinium chloride derivatives that are used as oxidation-reduction indicators. The general formula is 1,1'-di-R-4,4'-bipyridinium chloride, where R = methyl, ethyl, benzyl or, betaine.
The number of LYMPHOCYTES per unit volume of BLOOD.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Surgical removal of the thymus gland. (Dorland, 28th ed)

Reduction of aneurysm clip artifacts on CT angiograms: a technical note. (1/188)

We describe a head tilt technique for use with CT angiography that reduces beam-hardening artifacts in patients with aneurysm clips. This simple maneuver directs the artifacts away from pertinent anatomy, thus increasing the chances for diagnostic accuracy. No significant changes in the CT angiographic protocol are required, and the maneuver can easily be combined with other artifact-minimizing strategies.  (+info)

Digitized cerebral synchrotron radiation angiography: quantitative evaluation of the canine circle of Willis and its large and small branches. (2/188)

BACKGROUND AND PURPOSE: Conventional X-ray angiography lacks the sensitivity and spatial resolution needed to detect small amounts of iodinated contrast material and to quantitate diameters of the small vessels in the brain. The purpose of this study was to ascertain whether digitized synchrotron radiation microangiography, with the use of a high-definition TV camera system, can accurately show small cerebral vessels. METHODS: Six anesthetized dogs were exposed to monochromatic synchrotron radiation with an energy level of 33.3 keV optimized for iodine detection while iodinated contrast material was injected into the brachiocephalic and vertebral arteries. The images were detected with a high-definition TV camera system with a spatial resolution of 30 microm. In all, 26 cerebral angiograms of the circle of Willis with its branches were obtained, and the images were digitized at a workstation. RESULTS: The small branches of the circle of Willis were clearly visible on all images. Vasodilatation of the circle of Willis and its large and small branches induced by CO2 inhalation was quantitatively confirmed on the images: for example, the diameter of one small branch was increased from 0.24 +/- 0.04 mm to 0.38 +/- 0.12 mm. Temporal subtraction improved the image quality. CONCLUSION: The synchrotron radiation angiographic system is useful for visualizing large and small vessels deep in the brain as well as for quantitating their diameters.  (+info)

Influence of the collateral function of the circle of Willis on hemispherical perfusion during carotid occlusion as assessed by transcranial colour-coded duplex ultrasonography. (3/188)

OBJECTIVES: to investigate the collateral potential of the circle of Willis with transcranial colour-coded duplex ultrasonography and common carotid artery (CCA) compression. MATERIALS AND METHODS: in 46 atherosclerotic patients without cerebrovascular disease, the functional patency of the collaterals of the circle of Willis, the anterior and posterior communicating arteries, was assessed. The Peak Systolic Velocity (PSV) decrease in the middle cerebral artery (MCA) during CCA compression between complete and incomplete circles was compared. RESULTS: in 10 (22%) patients a complete and in 36 (78%) patients an incomplete circle of Willis was found, mainly due to non-functioning posterior communicating arteries. In hemispheres with collateral supply through both the anterior and the posterior communicating artery, the median PSV decrease in the MCA during CCA compression was 43%. When the posterior, anterior or both communicating arteries (1 hemisphere) were missing the PSV decrease was 58% (p =0.003), 70% (p =0.001) and 75%, respectively. CONCLUSIONS: collateral flow from the basilar to the carotid territory is often hampered by non-functioning posterior communicating arteries. A non-functioning anterior communicating artery is rare. A complete collateral circulation provides better perfusion of the MCA during carotid occlusion as compared with collateral supply through only the anterior or the posterior communicating artery in the case of an incomplete circle of Willis.  (+info)

Cerebral hemodynamics in relation to patterns of collateral flow. (4/188)

BACKGROUND AND PURPOSE: We sought to investigate the relation between collateral flow via different pathways and hemodynamic parameters measured by dynamic susceptibility contrast-enhanced MRI in patients with severe carotid artery disease. METHODS: Dynamic susceptibility contrast-enhanced MRI was performed in 66 patients and 33 control subjects. Patients had severe stenosis (>70%, n=12), unilateral occlusion (n=38), or bilateral occlusion (n=16) of the internal carotid artery (ICA). Cerebripetal flow and collateral flow via the circle of Willis were investigated with MR angiography. Collateral flow via the ophthalmic artery was investigated with transcranial Doppler sonography. RESULTS: Patients with ICA stenosis had well-preserved cerebral perfusion and were in general not dependent on collateral supply. Patients with unilateral ICA occlusion had impaired cerebral perfusion. However, appearance time, peak time, and mean transit time in white matter were less increased in patients with than in patients without collateral flow via the circle of Willis (P<0.05). Furthermore, patients with collateral flow via both anterior and posterior communicating arteries had less increased regional cerebral blood volume than patients with collateral flow via the posterior communicating artery only (P<0.05). Patients with bilateral ICA occlusion had severely compromised hemodynamic status despite recruitment of collateral supply. CONCLUSIONS: In patients with unilateral ICA occlusion, the pattern of collateral supply has significant influence on hemodynamic status. Collateral flow via the anterior communicating artery is a sign of well-preserved hemodynamic status, whereas no collateral flow via the circle of Willis or flow via only the posterior communicating artery is a sign of deteriorated cerebral perfusion.  (+info)

Tissue plasminogen activator (tPA) deficiency exacerbates cerebrovascular fibrin deposition and brain injury in a murine stroke model: studies in tPA-deficient mice and wild-type mice on a matched genetic background. (5/188)

Although the serine protease, tissue plasminogen activator (tPA), is approved by the US Food and Drug Administration for therapy to combat focal cerebral infarction, the basic concept of thrombolytic tPA therapy for stroke was challenged by recent studies that used genetically manipulated tPA-deficient (tPA-/-) mice, which suggested that tPA mediates ischemic neuronal damage. However, those studies were potentially flawed because the genotypes of tPA-/- and wild-type control mice were not entirely clear, and ischemic neuronal injury was evaluated in isolation of tPA effects on brain thrombosis. Using mice with appropriate genetic backgrounds and a middle cerebral artery occlusion stroke model with nonsiliconized thread, which does lead to microvascular thrombus formation, in the present study we determined the risk for cerebrovascular thrombosis and neuronal injury in tPA-/- and genetically matched tPA+/+ mice subjected to transient focal ischemia. Cerebrovascular fibrin deposition and the infarction volume were increased by 8.2- and 6. 7-fold in tPA-/- versus tPA+/+ mice, respectively, and these variables were correlated with reduced cerebral blood flow up to 58% (P<0.05) and impaired motor neurological score by 70% (P<0.05). Our findings indicate that tPA deficiency exacerbates ischemia-induced cerebrovascular thrombosis and that endogenous tPA protects the brain from an ischemic insult, presumably through its thrombolytic action. In addition, our study emphasizes the importance of appropriate genetic controls in murine stroke research.  (+info)

Comprehensive transcript analysis in small quantities of mRNA by SAGE-lite. (6/188)

Serial analysis of gene expression (SAGE) is a powerful technique that can be used for global analysis of gene expression. Its chief advantage over other methods is that SAGE does not require prior knowledge of the genes of interest and provides quantitative and qualitative data of potentially every transcribed sequence in a particular tissue or cell type. Furthermore, SAGE can quantify low-abundance transcripts and reliably detect relatively small differences in transcript abundance between cell populations. However, SAGE demands high input levels of mRNA which are often unavailable, particularly when studying human disease. To overcome this limitation, we have developed a modification of SAGE that allows detailed global analysis of gene expression in extremely small quantities of tissue or cultured cells. We have called this approach 'SAGE-Lite'. This technique was used for the global analysis of transcription in samples of normal and pathological human cerebrovasculature to study the molecular pathology of intracranial aneurysms. These samples, which are obtained during operative surgical repair, are typically no bigger than 1 or 2 mm and yield <100 ng of total RNA. In addition, we show that SAGE-Lite allows simple and rapid isolation of long cDNAs from short (15 bp) SAGE sequence tags.  (+info)

Circle of Willis collateral flow investigated by magnetic resonance angiography. (7/188)

BACKGROUND AND PURPOSE: The circle of Willis (CW) is considered an important collateral pathway in maintaining adequate cerebral blood flow in patients with internal carotid artery (ICA) obstruction. We aimed to investigate the anatomic variation of the CW in patients with severe symptomatic carotid obstructive disease and to analyze diameter changes of its components in relation to varying grades of ICA obstruction and in relation to the presence or absence of (retrograde) collateral flow. METHODS: Seventy-five patients with minor disabling neurological deficits and with ICA stenoses or occlusions were categorized into 4 groups according to the severity of ICA obstruction. This patient population reflected a relatively favorable subgroup of cerebral infarction (considering their minor neurological deficits). All subjects underwent magnetic resonance angiography, including magnetic resonance angiography sensitive to flow direction. CW morphology and the size of its components were determined and compared with those values in control subjects (n=100). RESULTS: Compared with control subjects, patients demonstrated a significantly higher percentage of entirely complete CW configurations (55% versus 36%, P=0.02), complete anterior configurations (88% versus 68%, P=0.002), and complete posterior CW configurations (63% versus 47%, P=0.04). Patients with severe ICA stenosis did not show significantly increased CW vessel diameters. Patients with ICA occlusion demonstrated a high prevalence of collateral flow through the anterior CW and significantly increased diameters of the communicating channels. Patients with bilateral ICA occlusion relied on collateral flow via the posterior CW and demonstrated a bilateral increase in posterior communicating artery diameters (P<0.05). CONCLUSIONS: The anatomic and functional configuration of the CW reflects the degree of ICA obstruction.  (+info)

Contrast-enhanced transcranial color-coded duplexsonography in stroke patients with limited bone windows. (8/188)

BACKGROUND AND PURPOSE: Thickening of the temporal bone in stroke-age patients may obviate sonographic evaluation of the circle of Willis in 20% to 30% of patients. We assessed the diagnostic efficacy of contrast-enhanced transcranial color-coded duplexsonography (TCCD) for noninvasive evaluation of the circle of Willis in stroke patients with limited bone windows. METHODS: Of 171 consecutive patients who presented with ischemic symptoms in the middle cerebral artery (MCA) territory, 49 patients (32 female, 17 male; age range, 70.5+/-10.6 years) had no detectable colorflow signals from the circle of Willis by TCCD because of limited acoustic windows. These 49 patients received an IV injection of a sonographic contrast-enhancing agent, Levovist (Schering; Berlin, Germany), and were re-examined. Correlative imaging studies of the circle of Willis were obtained in 42 of 49 of these patients. RESULTS: In 38 of 49 patients, contrast-enhanced TCCD enabled full visualization of the circle of Willis bilaterally; in an additional five patients, contrast-enhanced TCCD revealed only the portion of the circle of Willis ipsilateral to the probe through one temporal bone. In six of these 43 patients, contrast-enhanced TCCD showed MCA stenosis and MCA occlusion in three; three of the six cases of MCA stenosis and all three cases of the MCA occlusion were found on the symptomatic side. In six of 49 patients, no colorflow signals were obtained after contrast enhancement. All contrast-enhanced TCCD findings were confirmed by CT angiography, transfemoral digital subtraction angiography, MR angiography, or a combination of all three correlative studies. Levovist produced no serious adverse events. CONCLUSION: In stroke-age patients with limited acoustic windows, contrast-enhancement with Levovist can markedly increase the sensitivity of TCCD and increase the detection of clinically relevant intracranial arterial disease.  (+info)

The Circle of Willis is a circulatory arrangement in the brain where the major arteries that supply blood to the brain converge to form an almost circular structure. It is named after Thomas Willis, an English physician who first described it in 1664.

This circle is formed by the joining of the two internal carotid arteries, which divide into the anterior cerebral and middle cerebral arteries, with the basilar artery, which arises from the vertebral arteries. These vessels anastomose, or connect, to form a polygon-like structure at the base of the brain.

The Circle of Willis plays a crucial role in maintaining adequate blood flow to the brain, as it allows for collateral circulation. If one of the arteries that make up the circle becomes blocked or narrowed, blood can still reach the affected area through the other vessels in the circle. This helps to minimize the risk of stroke and other neurological disorders.

Cerebral arteries refer to the blood vessels that supply oxygenated blood to the brain. These arteries branch off from the internal carotid arteries and the vertebral arteries, which combine to form the basilar artery. The major cerebral arteries include:

1. Anterior cerebral artery (ACA): This artery supplies blood to the frontal lobes of the brain, including the motor and sensory cortices responsible for movement and sensation in the lower limbs.
2. Middle cerebral artery (MCA): The MCA is the largest of the cerebral arteries and supplies blood to the lateral surface of the brain, including the temporal, parietal, and frontal lobes. It is responsible for providing blood to areas involved in motor function, sensory perception, speech, memory, and vision.
3. Posterior cerebral artery (PCA): The PCA supplies blood to the occipital lobe, which is responsible for visual processing, as well as parts of the temporal and parietal lobes.
4. Anterior communicating artery (ACoA) and posterior communicating arteries (PComAs): These are small arteries that connect the major cerebral arteries, forming an important circulatory network called the Circle of Willis. The ACoA connects the two ACAs, while the PComAs connect the ICA with the PCA and the basilar artery.

These cerebral arteries play a crucial role in maintaining proper brain function by delivering oxygenated blood to various regions of the brain. Any damage or obstruction to these arteries can lead to serious neurological conditions, such as strokes or transient ischemic attacks (TIAs).

Collateral circulation refers to the alternate blood supply routes that bypass an obstructed or narrowed vessel and reconnect with the main vascular system. These collateral vessels can develop over time as a result of the body's natural adaptation to chronic ischemia (reduced blood flow) caused by various conditions such as atherosclerosis, thromboembolism, or vasculitis.

The development of collateral circulation helps maintain adequate blood flow and oxygenation to affected tissues, minimizing the risk of tissue damage and necrosis. In some cases, well-developed collateral circulations can help compensate for significant blockages in major vessels, reducing symptoms and potentially preventing the need for invasive interventions like revascularization procedures. However, the extent and effectiveness of collateral circulation vary from person to person and depend on factors such as age, overall health status, and the presence of comorbidities.

Circular DNA is a type of DNA molecule that forms a closed loop, rather than the linear double helix structure commonly associated with DNA. This type of DNA is found in some viruses, plasmids (small extrachromosomal DNA molecules found in bacteria), and mitochondria and chloroplasts (organelles found in plant and animal cells).

Circular DNA is characterized by the absence of telomeres, which are the protective caps found on linear chromosomes. Instead, circular DNA has a specific sequence where the two ends join together, known as the origin of replication and the replication terminus. This structure allows for the DNA to be replicated efficiently and compactly within the cell.

Because of its circular nature, circular DNA is more resistant to degradation by enzymes that cut linear DNA, making it more stable in certain environments. Additionally, the ability to easily manipulate and clone circular DNA has made it a valuable tool in molecular biology and genetic engineering.

Magnetic Resonance Angiography (MRA) is a non-invasive medical imaging technique that uses magnetic fields and radio waves to create detailed images of the blood vessels or arteries within the body. It is a type of Magnetic Resonance Imaging (MRI) that focuses specifically on the circulatory system.

MRA can be used to diagnose and evaluate various conditions related to the blood vessels, such as aneurysms, stenosis (narrowing of the vessel), or the presence of plaques or tumors. It can also be used to plan for surgeries or other treatments related to the vascular system. The procedure does not use radiation and is generally considered safe, although people with certain implants like pacemakers may not be able to have an MRA due to safety concerns.

I'm sorry for any confusion, but "Management Quality Circles" is not a recognized medical term or concept in healthcare management. It appears to be a term that combines the general business concept of "Quality Circles" with "Management," which may refer to a specific approach used in management and continuous improvement.

In the context of business and management, Quality Circles are small groups of employees who meet regularly to identify, analyze, and solve work-related problems and issues, with an aim to improve quality and productivity. The concept is often associated with Total Quality Management (TQM) and Continuous Quality Improvement (CQI).

However, if you're looking for a term related to healthcare management or medical definitions, please provide more context so I can give you a more accurate answer.

Neuroendoscopy is a minimally invasive surgical technique that involves the use of an endoscope to access and treat various conditions within the brain and spinal column. An endoscope is a long, flexible tube with a light and camera at its tip, which allows surgeons to view and operate on internal structures through small incisions or natural openings in the body.

In neuroendoscopy, the surgeon uses the endoscope to navigate through the brain's ventricular system (fluid-filled spaces) or other narrow spaces within the skull or spine to diagnose and treat conditions such as hydrocephalus, brain tumors, arachnoid cysts, and intraventricular hemorrhage.

The benefits of neuroendoscopy include reduced trauma to surrounding tissues, shorter hospital stays, faster recovery times, and improved outcomes compared to traditional open surgical approaches. However, neuroendoscopic procedures require specialized training and expertise due to the complexity of the anatomy involved.

The internal carotid artery is a major blood vessel that supplies oxygenated blood to the brain. It originates from the common carotid artery and passes through the neck, entering the skull via the carotid canal in the temporal bone. Once inside the skull, it branches into several smaller vessels that supply different parts of the brain with blood.

The internal carotid artery is divided into several segments: cervical, petrous, cavernous, clinoid, and supraclinoid. Each segment has distinct clinical significance in terms of potential injury or disease. The most common conditions affecting the internal carotid artery include atherosclerosis, which can lead to stroke or transient ischemic attack (TIA), and dissection, which can cause severe headache, neck pain, and neurological symptoms.

It's important to note that any blockage or damage to the internal carotid artery can have serious consequences, as it can significantly reduce blood flow to the brain and lead to permanent neurological damage or even death. Therefore, regular check-ups and screening tests are recommended for individuals at high risk of developing vascular diseases.

Cerebrovascular circulation refers to the network of blood vessels that supply oxygenated blood and nutrients to the brain tissue, and remove waste products. It includes the internal carotid arteries, vertebral arteries, circle of Willis, and the intracranial arteries that branch off from them.

The internal carotid arteries and vertebral arteries merge to form the circle of Willis, a polygonal network of vessels located at the base of the brain. The anterior cerebral artery, middle cerebral artery, posterior cerebral artery, and communicating arteries are the major vessels that branch off from the circle of Willis and supply blood to different regions of the brain.

Interruptions or abnormalities in the cerebrovascular circulation can lead to various neurological conditions such as stroke, transient ischemic attack (TIA), and vascular dementia.

Moyamoya Disease is a rare, progressive cerebrovascular disorder characterized by the narrowing or occlusion (blockage) of the internal carotid artery and its main branches. The name "moyamoya" means "puff of smoke" in Japanese and describes the look of the tangle of tiny vessels formed to compensate for the blockage. Over time, these fragile vessels can become less effective or rupture, leading to transient ischemic attacks (mini-strokes), strokes, bleeding in the brain, or cognitive decline. The exact cause of moyamoya disease is unknown, but it may be associated with genetic factors and certain medical conditions such as Down syndrome, neurofibromatosis type 1, and sickle cell anemia. Treatment options include surgical procedures to improve blood flow to the brain.

Cerebral angiography is a medical procedure that involves taking X-ray images of the blood vessels in the brain after injecting a contrast dye into them. This procedure helps doctors to diagnose and treat various conditions affecting the blood vessels in the brain, such as aneurysms, arteriovenous malformations, and stenosis (narrowing of the blood vessels).

During the procedure, a catheter is inserted into an artery in the leg and threaded through the body to the blood vessels in the neck or brain. The contrast dye is then injected through the catheter, and X-ray images are taken to visualize the blood flow through the brain's blood vessels.

Cerebral angiography provides detailed images of the blood vessels in the brain, allowing doctors to identify any abnormalities or blockages that may be causing symptoms or increasing the risk of stroke. Based on the results of the cerebral angiography, doctors can develop a treatment plan to address these issues and prevent further complications.

The Doppler effect, also known as the Doppler shift, is a change in frequency or wavelength of a wave in relation to an observer who is moving relative to the source of the wave. It was first described by Austrian physicist Christian Doppler in 1842.

In the context of medical ultrasound, the Doppler effect is used to measure the velocity of blood flow in the body. When the ultrasound waves encounter moving red blood cells, the frequency of the reflected waves changes due to the Doppler effect. This change in frequency can be used to calculate the speed and direction of blood flow.

Doppler ultrasound is commonly used in medical imaging to assess conditions such as heart valve function, blood clots, and narrowed or blocked blood vessels. It can also be used to monitor fetal heart rate and blood flow during pregnancy.

Digital subtraction angiography (DSA) is a medical imaging technique used to visualize the blood vessels and blood flow within the body. It combines the use of X-ray technology with digital image processing to produce detailed images of the vascular system.

In DSA, a contrast agent is injected into the patient's bloodstream through a catheter, which is typically inserted into an artery in the leg and guided to the area of interest using fluoroscopy. As the contrast agent flows through the blood vessels, X-ray images are taken at multiple time points.

The digital subtraction process involves taking a baseline image without contrast and then subtracting it from subsequent images taken with contrast. This allows for the removal of background structures and noise, resulting in clearer images of the blood vessels. DSA can be used to diagnose and evaluate various vascular conditions, such as aneurysms, stenosis, and tumors, and can also guide interventional procedures such as angioplasty and stenting.

Intracranial arteriosclerosis is a medical condition characterized by the thickening and hardening of the walls of the intracranial arteries, which are the blood vessels that supply blood to the brain. This process is caused by the buildup of plaque, made up of fat, cholesterol, and other substances, within the walls of the arteries.

Intracranial arteriosclerosis can lead to a narrowing or blockage of the affected arteries, reducing blood flow to the brain. This can result in various neurological symptoms, such as headaches, dizziness, seizures, and transient ischemic attacks (TIAs) or strokes.

The condition is more common in older adults, particularly those with a history of hypertension, diabetes, smoking, and high cholesterol levels. Intracranial arteriosclerosis can be diagnosed through imaging tests such as magnetic resonance angiography (MRA) or computed tomographic angiography (CTA). Treatment typically involves managing risk factors and may include medications to control blood pressure, cholesterol levels, and prevent blood clots. In severe cases, surgical procedures such as angioplasty and stenting may be necessary to open up the affected arteries.

Transcranial Doppler ultrasonography is a non-invasive diagnostic technique that uses high-frequency sound waves to visualize and measure the velocity of blood flow in the cerebral arteries located in the skull. This imaging modality employs the Doppler effect, which describes the change in frequency of sound waves as they reflect off moving red blood cells. By measuring the frequency shift of the reflected ultrasound waves, the velocity and direction of blood flow can be determined.

Transcranial Doppler ultrasonography is primarily used to assess cerebrovascular circulation and detect abnormalities such as stenosis (narrowing), occlusion (blockage), or embolism (obstruction) in the intracranial arteries. It can also help monitor patients with conditions like sickle cell disease, vasospasm following subarachnoid hemorrhage, and evaluate the effectiveness of treatments such as thrombolysis or angioplasty. The procedure is typically performed by placing a transducer on the patient's skull after applying a coupling gel, and it does not involve radiation exposure or contrast agents.

The basilar artery is a major blood vessel that supplies oxygenated blood to the brainstem and cerebellum. It is formed by the union of two vertebral arteries at the lower part of the brainstem, near the junction of the medulla oblongata and pons.

The basilar artery runs upward through the center of the brainstem and divides into two posterior cerebral arteries at the upper part of the brainstem, near the midbrain. The basilar artery gives off several branches that supply blood to various parts of the brainstem, including the pons, medulla oblongata, and midbrain, as well as to the cerebellum.

The basilar artery is an important part of the circle of Willis, a network of arteries at the base of the brain that ensures continuous blood flow to the brain even if one of the arteries becomes blocked or narrowed.

I believe there might be a bit of confusion in your question. A "history" in medical terms usually refers to the detailed account of a patient's symptoms, illnesses, and treatments received, which is used by healthcare professionals to understand their health status and provide appropriate care. It is not typically associated with a specific century like the 17th century.

If you are asking for information about the medical practices or significant developments in the field of medicine during the 17th century, I would be happy to provide some insight into that. The 17th century was a time of great advancement in medical knowledge and practice, with several key figures and events shaping the course of medical history.

Some notable developments in medicine during the 17th century include:

1. William Harvey's discovery of the circulation of blood (1628): English physician William Harvey published his groundbreaking work "De Motu Cordis" (On the Motion of the Heart and Blood), which described the circulatory system and the role of the heart in pumping blood throughout the body. This discovery fundamentally changed our understanding of human anatomy and physiology.
2. The development of the microscope (1600s): The invention of the microscope allowed scientists to observe structures that were previously invisible to the naked eye, such as cells, bacteria, and other microorganisms. This technology opened up new avenues of research in anatomy, physiology, and pathology, paving the way for modern medical science.
3. The establishment of the Royal Society (1660): The Royal Society, a prominent scientific organization in the UK, was founded during this century to promote scientific inquiry and share knowledge among its members. Many notable scientists and physicians, including Robert Hooke and Christopher Wren, were part of the society and contributed significantly to the advancement of medical science.
4. The Smallpox Vaccination (1796): Although this occurred near the end of the 18th century, the groundwork for Edward Jenner's smallpox vaccine was laid during the 17th century. Smallpox was a significant public health issue during this time, and Jenner's development of an effective vaccine marked a major milestone in the history of medicine and public health.
5. The work of Sylvius de le Boe (1614-1672): A Dutch physician and scientist, Sylvius de le Boe made significant contributions to our understanding of human anatomy and physiology. He was the first to describe the circulation of blood in the lungs and identified the role of the liver in metabolism.

These are just a few examples of the many advancements that took place during the 17th century, shaping the course of medical history and laying the foundation for modern medicine.

The vertebral artery is a major blood vessel that supplies oxygenated blood to the brain and upper spinal cord. It arises from the subclavian artery, then ascends through the transverse processes of several cervical vertebrae before entering the skull through the foramen magnum. Inside the skull, it joins with the opposite vertebral artery to form the basilar artery, which supplies blood to the brainstem and cerebellum. The vertebral artery also gives off several important branches that supply blood to various regions of the brainstem and upper spinal cord.

An intracranial aneurysm is a localized, blood-filled dilation or bulging in the wall of a cerebral artery within the skull (intracranial). These aneurysms typically occur at weak points in the arterial walls, often at branching points where the vessel divides into smaller branches. Over time, the repeated pressure from blood flow can cause the vessel wall to weaken and balloon out, forming a sac-like structure. Intracranial aneurysms can vary in size, ranging from a few millimeters to several centimeters in diameter.

There are three main types of intracranial aneurysms:

1. Saccular (berry) aneurysm: This is the most common type, characterized by a round or oval shape with a narrow neck and a bulging sac. They usually develop at branching points in the arteries due to congenital weaknesses in the vessel wall.
2. Fusiform aneurysm: These aneurysms have a dilated segment along the length of the artery, forming a cigar-shaped or spindle-like structure. They are often caused by atherosclerosis and can affect any part of the cerebral arteries.
3. Dissecting aneurysm: This type occurs when there is a tear in the inner lining (intima) of the artery, allowing blood to flow between the layers of the vessel wall. It can lead to narrowing or complete blockage of the affected artery and may cause subarachnoid hemorrhage if it ruptures.

Intracranial aneurysms can be asymptomatic and discovered incidentally during imaging studies for other conditions. However, when they grow larger or rupture, they can lead to severe complications such as subarachnoid hemorrhage, stroke, or even death. Treatment options include surgical clipping, endovascular coiling, or flow diversion techniques to prevent further growth and potential rupture of the aneurysm.

The sphenoid bone is a complex, irregularly shaped bone located in the middle cranial fossa and forms part of the base of the skull. It articulates with several other bones, including the frontal, parietal, temporal, ethmoid, palatine, and zygomatic bones. The sphenoid bone has two main parts: the body and the wings.

The body of the sphenoid bone is roughly cuboid in shape and contains several important structures, such as the sella turcica, which houses the pituitary gland, and the sphenoid sinuses, which are air-filled cavities within the bone. The greater wings of the sphenoid bone extend laterally from the body and form part of the skull's lateral walls. They contain the superior orbital fissure, through which important nerves and blood vessels pass between the cranial cavity and the orbit of the eye.

The lesser wings of the sphenoid bone are thin, blade-like structures that extend anteriorly from the body and form part of the floor of the anterior cranial fossa. They contain the optic canal, which transmits the optic nerve and ophthalmic artery between the brain and the orbit of the eye.

Overall, the sphenoid bone plays a crucial role in protecting several important structures within the skull, including the pituitary gland, optic nerves, and ophthalmic arteries.

Carotid stenosis is a medical condition that refers to the narrowing or constriction of the lumen (inner space) of the carotid artery. The carotid arteries are major blood vessels that supply oxygenated blood to the head and neck. Carotid stenosis usually results from the buildup of plaque, made up of fat, cholesterol, calcium, and other substances, on the inner walls of the artery. This process is called atherosclerosis.

As the plaque accumulates, it causes the artery to narrow, reducing blood flow to the brain. Severe carotid stenosis can increase the risk of stroke, as a clot or debris from the plaque can break off and travel to the brain, blocking a smaller blood vessel and causing tissue damage or death.

Carotid stenosis is typically diagnosed through imaging tests such as ultrasound, CT angiography, or MRI angiography. Treatment options may include lifestyle modifications (such as quitting smoking, controlling blood pressure, and managing cholesterol levels), medications to reduce the risk of clots, or surgical procedures like endarterectomy or stenting to remove or bypass the blockage.

The external carotid artery is a major blood vessel in the neck that supplies oxygenated blood to the structures of the head and neck, excluding the brain. It originates from the common carotid artery at the level of the upper border of the thyroid cartilage, then divides into several branches that supply various regions of the head and neck, including the face, scalp, ears, and neck muscles.

The external carotid artery has eight branches:

1. Superior thyroid artery: Supplies blood to the thyroid gland, larynx, and surrounding muscles.
2. Ascending pharyngeal artery: Supplies blood to the pharynx, palate, and meninges of the brain.
3. Lingual artery: Supplies blood to the tongue and floor of the mouth.
4. Facial artery: Supplies blood to the face, nose, lips, and palate.
5. Occipital artery: Supplies blood to the scalp and muscles of the neck.
6. Posterior auricular artery: Supplies blood to the ear and surrounding muscles.
7. Maxillary artery: Supplies blood to the lower face, nasal cavity, palate, and meninges of the brain.
8. Superficial temporal artery: Supplies blood to the scalp, face, and temporomandibular joint.

The external carotid artery is an essential structure for maintaining adequate blood flow to the head and neck, and any damage or blockage can lead to serious medical conditions such as stroke or tissue necrosis.

The arachnoid is one of the three membranes that cover the brain and the spinal cord, known as the meninges. It is located between the dura mater (the outermost layer) and the pia mater (the innermost layer). The arachnoid is a thin, delicate membrane that is filled with cerebrospinal fluid, which provides protection and nutrition to the central nervous system.

The arachnoid has a spider-web like appearance, hence its name, and it is composed of several layers of collagen fibers and elastic tissue. It is highly vascularized, meaning that it contains many blood vessels, and it plays an important role in regulating the flow of cerebrospinal fluid around the brain and spinal cord.

In some cases, the arachnoid can become inflamed or irritated, leading to a condition called arachnoiditis. This can cause a range of symptoms, including pain, muscle weakness, and sensory changes, and it may require medical treatment to manage.

Echoencephalography (EEG) is a type of neurosonology technique that uses ultrasound to assess the structures of the brain and detect any abnormalities. It is also known as brain ultrasound or transcranial Doppler ultrasound. This non-invasive procedure involves placing a small ultrasound probe on the skull, which emits sound waves that travel through the skull and bounce back (echo) when they reach the brain tissue. The resulting echoes are then analyzed to create images of the brain's structures, including the ventricles, cerebral arteries, and other blood vessels.

EEG is often used in infants and young children, as their skulls are still thin enough to allow for clear ultrasound imaging. It can help diagnose conditions such as hydrocephalus (fluid buildup in the brain), intracranial hemorrhage (bleeding in the brain), stroke, and other neurological disorders. EEG is a safe and painless procedure that does not require any radiation or contrast agents, making it an attractive alternative to other imaging techniques such as CT or MRI scans. However, its use is limited in older children and adults due to the thickening of the skull bones, which can make it difficult to obtain clear images.

"Migraine with Aura" is a neurological condition that is formally defined by the International Classification of Headache Disorders (ICHD) as follows:

"An migraine attack with focal neurological symptoms that usually develop gradually over 5 to 20 minutes and last for less than 60 minutes. Motor weakness is not a feature of the aura."

The symptoms of an aura may include visual disturbances such as flickering lights, zigzag lines, or blind spots; sensory disturbances such as tingling or numbness in the face, arms, or legs; and speech or language difficulties. These symptoms are caused by abnormal electrical activity in the brain and typically precede or accompany a migraine headache, although they can also occur without a headache.

It's important to note that not all people who experience migraines will have an aura, and some people may have an aura without a headache. If you are experiencing symptoms of a migraine with aura or any other type of headache, it is recommended that you consult with a healthcare professional for proper diagnosis and treatment.

The ophthalmic artery is the first branch of the internal carotid artery, which supplies blood to the eye and its adnexa. It divides into several branches that provide oxygenated blood to various structures within the eye, including the retina, optic nerve, choroid, iris, ciliary body, and cornea. Any blockage or damage to the ophthalmic artery can lead to serious vision problems or even blindness.

A Carotid-Cavernous Sinus Fistula (CCSF) is an abnormal connection between the carotid artery and the cavernous sinus, a venous structure in the skull. This connection can be either direct or indirect. Direct CCSFs are caused by trauma or rupture of an aneurysm, while indirect CCSFs are usually spontaneous and associated with conditions such as hypertension, atherosclerosis, or connective tissue disorders.

Symptoms of a CCSF may include headache, eye redness, protrusion of the eyeball, double vision, hearing disturbances, and pulsatile tinnitus (a rhythmic sound in the ear). The severity of symptoms can vary depending on the size of the fistula and the pressure within the cavernous sinus.

Treatment options for CCSF include endovascular repair with stenting or coiling, surgical closure, or observation, depending on the type and size of the fistula and the presence of symptoms.

Intracranial arteriovenous malformations (AVMs) are abnormal, tangled connections between the arteries and veins in the brain. These connections bypass the capillary system, which can lead to high-flow shunting and potential complications such as hemorrhage, stroke, or neurological deficits. AVMs are congenital conditions, meaning they are present at birth, although symptoms may not appear until later in life. They are relatively rare, affecting approximately 0.1% of the population. Treatment options for AVMs include surgery, radiation therapy, and endovascular embolization, depending on the size, location, and specific characteristics of the malformation.

The posterior cranial fossa is a term used in anatomy to refer to the portion of the skull that forms the lower, back part of the cranial cavity. It is located between the occipital bone and the temporal bones, and it contains several important structures including the cerebellum, pons, medulla oblongata, and the lower cranial nerves (IX-XII). The posterior fossa also contains the foramen magnum, which is a large opening through which the spinal cord connects to the brainstem. This region of the skull is protected by the occipital bone, which forms the base of the skull and provides attachment for several neck muscles.

The skull base is the lower part of the skull that forms the floor of the cranial cavity and the roof of the facial skeleton. It is a complex anatomical region composed of several bones, including the frontal, sphenoid, temporal, occipital, and ethmoid bones. The skull base supports the brain and contains openings for blood vessels and nerves that travel between the brain and the face or neck. The skull base can be divided into three regions: the anterior cranial fossa, middle cranial fossa, and posterior cranial fossa, which house different parts of the brain.

Blood flow velocity is the speed at which blood travels through a specific part of the vascular system. It is typically measured in units of distance per time, such as centimeters per second (cm/s) or meters per second (m/s). Blood flow velocity can be affected by various factors, including cardiac output, vessel diameter, and viscosity of the blood. Measuring blood flow velocity is important in diagnosing and monitoring various medical conditions, such as heart disease, stroke, and peripheral vascular disease.

Cerebral infarction, also known as a "stroke" or "brain attack," is the sudden death of brain cells caused by the interruption of their blood supply. It is most commonly caused by a blockage in one of the blood vessels supplying the brain (an ischemic stroke), but can also result from a hemorrhage in or around the brain (a hemorrhagic stroke).

Ischemic strokes occur when a blood clot or other particle blocks a cerebral artery, cutting off blood flow to a part of the brain. The lack of oxygen and nutrients causes nearby brain cells to die. Hemorrhagic strokes occur when a weakened blood vessel ruptures, causing bleeding within or around the brain. This bleeding can put pressure on surrounding brain tissues, leading to cell death.

Symptoms of cerebral infarction depend on the location and extent of the affected brain tissue but may include sudden weakness or numbness in the face, arm, or leg; difficulty speaking or understanding speech; vision problems; loss of balance or coordination; and severe headache with no known cause. Immediate medical attention is crucial for proper diagnosis and treatment to minimize potential long-term damage or disability.

Cerebrovascular disorders are a group of medical conditions that affect the blood vessels of the brain. These disorders can be caused by narrowing, blockage, or rupture of the blood vessels, leading to decreased blood flow and oxygen supply to the brain. The most common types of cerebrovascular disorders include:

1. Stroke: A stroke occurs when a blood vessel in the brain becomes blocked or bursts, causing a lack of oxygen and nutrients to reach brain cells. This can lead to permanent damage or death of brain tissue.
2. Transient ischemic attack (TIA): Also known as a "mini-stroke," a TIA occurs when blood flow to the brain is temporarily blocked, often by a blood clot. Symptoms may last only a few minutes to a few hours and typically resolve on their own. However, a TIA is a serious warning sign that a full-blown stroke may occur in the future.
3. Aneurysm: An aneurysm is a weakened or bulging area in the wall of a blood vessel. If left untreated, an aneurysm can rupture and cause bleeding in the brain.
4. Arteriovenous malformation (AVM): An AVM is a tangled mass of abnormal blood vessels that connect arteries and veins. This can lead to bleeding in the brain or stroke.
5. Carotid stenosis: Carotid stenosis occurs when the carotid arteries, which supply blood to the brain, become narrowed or blocked due to plaque buildup. This can increase the risk of stroke.
6. Vertebrobasilar insufficiency: This condition occurs when the vertebral and basilar arteries, which supply blood to the back of the brain, become narrowed or blocked. This can lead to symptoms such as dizziness, vertigo, and difficulty swallowing.

Cerebrovascular disorders are a leading cause of disability and death worldwide. Risk factors for these conditions include age, high blood pressure, smoking, diabetes, high cholesterol, and family history. Treatment may involve medications, surgery, or lifestyle changes to reduce the risk of further complications.

Pia Mater is the inner-most layer of the meninges, which are the protective coverings of the brain and spinal cord. It is a very thin and highly vascularized (rich in blood vessels) membrane that closely adheres to the surface of the brain. The name "Pia Mater" comes from Latin, meaning "tender mother." This layer provides nutrition and protection to the brain, and it also allows for the movement and flexibility of the brain within the skull.

Cerebral dominance is a concept in neuropsychology that refers to the specialization of one hemisphere of the brain over the other for certain cognitive functions. In most people, the left hemisphere is dominant for language functions such as speaking and understanding spoken or written language, while the right hemisphere is dominant for non-verbal functions such as spatial ability, face recognition, and artistic ability.

Cerebral dominance does not mean that the non-dominant hemisphere is incapable of performing the functions of the dominant hemisphere, but rather that it is less efficient or specialized in those areas. The concept of cerebral dominance has been used to explain individual differences in cognitive abilities and learning styles, as well as the laterality of brain damage and its effects on cognition and behavior.

It's important to note that cerebral dominance is a complex phenomenon that can vary between individuals and can be influenced by various factors such as genetics, environment, and experience. Additionally, recent research has challenged the strict lateralization of functions and suggested that there is more functional overlap and interaction between the two hemispheres than previously thought.

The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:

1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.

The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.

Three-dimensional (3D) imaging in medicine refers to the use of technologies and techniques that generate a 3D representation of internal body structures, organs, or tissues. This is achieved by acquiring and processing data from various imaging modalities such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, or confocal microscopy. The resulting 3D images offer a more detailed visualization of the anatomy and pathology compared to traditional 2D imaging techniques, allowing for improved diagnostic accuracy, surgical planning, and minimally invasive interventions.

In 3D imaging, specialized software is used to reconstruct the acquired data into a volumetric model, which can be manipulated and viewed from different angles and perspectives. This enables healthcare professionals to better understand complex anatomical relationships, detect abnormalities, assess disease progression, and monitor treatment response. Common applications of 3D imaging include neuroimaging, orthopedic surgery planning, cancer staging, dental and maxillofacial reconstruction, and interventional radiology procedures.

Brain ischemia is the medical term used to describe a reduction or interruption of blood flow to the brain, leading to a lack of oxygen and glucose delivery to brain tissue. This can result in brain damage or death of brain cells, known as infarction. Brain ischemia can be caused by various conditions such as thrombosis (blood clot formation), embolism (obstruction of a blood vessel by a foreign material), or hypoperfusion (reduced blood flow). The severity and duration of the ischemia determine the extent of brain damage. Symptoms can range from mild, such as transient ischemic attacks (TIAs or "mini-strokes"), to severe, including paralysis, speech difficulties, loss of consciousness, and even death. Immediate medical attention is required for proper diagnosis and treatment to prevent further damage and potential long-term complications.

A subarachnoid hemorrhage is a type of stroke that results from bleeding into the space surrounding the brain, specifically within the subarachnoid space which contains cerebrospinal fluid (CSF). This space is located between the arachnoid membrane and the pia mater, two of the three layers that make up the meninges, the protective covering of the brain and spinal cord.

The bleeding typically originates from a ruptured aneurysm, a weakened area in the wall of a cerebral artery, or less commonly from arteriovenous malformations (AVMs) or head trauma. The sudden influx of blood into the CSF-filled space can cause increased intracranial pressure, irritation to the brain, and vasospasms, leading to further ischemia and potential additional neurological damage.

Symptoms of a subarachnoid hemorrhage may include sudden onset of severe headache (often described as "the worst headache of my life"), neck stiffness, altered mental status, nausea, vomiting, photophobia, and focal neurological deficits. Rapid diagnosis and treatment are crucial to prevent further complications and improve the chances of recovery.

A cadaver is a deceased body that is used for medical research or education. In the field of medicine, cadavers are often used in anatomy lessons, surgical training, and other forms of medical research. The use of cadavers allows medical professionals to gain a deeper understanding of the human body and its various systems without causing harm to living subjects. Cadavers may be donated to medical schools or obtained through other means, such as through consent of the deceased or their next of kin. It is important to handle and treat cadavers with respect and dignity, as they were once living individuals who deserve to be treated with care even in death.

Ultrasonography, Doppler, color is a type of diagnostic ultrasound technique that uses the Doppler effect to produce visual images of blood flow in vessels and the heart. The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the source of the wave. In this context, it refers to the change in frequency of the ultrasound waves as they reflect off moving red blood cells.

In color Doppler ultrasonography, different colors are used to represent the direction and speed of blood flow. Red typically represents blood flowing toward the transducer (the device that sends and receives sound waves), while blue represents blood flowing away from the transducer. The intensity or brightness of the color is proportional to the velocity of blood flow.

Color Doppler ultrasonography is often used in conjunction with grayscale ultrasound imaging, which provides information about the structure and composition of tissues. Together, these techniques can help diagnose a wide range of conditions, including heart disease, blood clots, and abnormalities in blood flow.

Arterial occlusive diseases are medical conditions characterized by the blockage or narrowing of the arteries, which can lead to a reduction in blood flow to various parts of the body. This reduction in blood flow can cause tissue damage and may result in serious complications such as tissue death (gangrene), organ dysfunction, or even death.

The most common cause of arterial occlusive diseases is atherosclerosis, which is the buildup of plaque made up of fat, cholesterol, calcium, and other substances in the inner lining of the artery walls. Over time, this plaque can harden and narrow the arteries, restricting blood flow. Other causes of arterial occlusive diseases include blood clots, emboli (tiny particles that travel through the bloodstream and lodge in smaller vessels), inflammation, trauma, and certain inherited conditions.

Symptoms of arterial occlusive diseases depend on the location and severity of the blockage. Common symptoms include:

* Pain, cramping, or fatigue in the affected limb, often triggered by exercise and relieved by rest (claudication)
* Numbness, tingling, or weakness in the affected limb
* Coldness or discoloration of the skin in the affected area
* Slow-healing sores or wounds on the toes, feet, or legs
* Erectile dysfunction in men

Treatment for arterial occlusive diseases may include lifestyle changes such as quitting smoking, exercising regularly, and eating a healthy diet. Medications to lower cholesterol, control blood pressure, prevent blood clots, or manage pain may also be prescribed. In severe cases, surgical procedures such as angioplasty, stenting, or bypass surgery may be necessary to restore blood flow.

A Transient Ischemic Attack (TIA), also known as a "mini-stroke," is a temporary period of symptoms similar to those you'd get if you were having a stroke. A TIA doesn't cause permanent damage and is often caused by a temporary decrease in blood supply to part of your brain, which may last as little as five minutes.

Like an ischemic stroke, a TIA occurs when a clot or debris blocks blood flow to part of your nervous system. However, unlike a stroke, a TIA doesn't leave lasting damage because the blockage is temporary.

Symptoms of a TIA can include sudden onset of weakness, numbness or paralysis in your face, arm or leg, typically on one side of your body. You could also experience slurred or garbled speech, or difficulty understanding others. Other symptoms can include blindness in one or both eyes, dizziness, or a severe headache with no known cause.

Even though TIAs usually last only a few minutes, they are a serious condition and should not be ignored. If you suspect you or someone else is experiencing a TIA, seek immediate medical attention. TIAs can be a warning sign that a full-blown stroke is imminent.

The carotid arteries are a pair of vital blood vessels in the human body that supply oxygenated blood to the head and neck. Each person has two common carotid arteries, one on each side of the neck, which branch off from the aorta, the largest artery in the body.

The right common carotid artery originates from the brachiocephalic trunk, while the left common carotid artery arises directly from the aortic arch. As they ascend through the neck, they split into two main branches: the internal and external carotid arteries.

The internal carotid artery supplies oxygenated blood to the brain, eyes, and other structures within the skull, while the external carotid artery provides blood to the face, scalp, and various regions of the neck.

Maintaining healthy carotid arteries is crucial for overall cardiovascular health and preventing serious conditions like stroke, which can occur when the arteries become narrowed or blocked due to the buildup of plaque or fatty deposits (atherosclerosis). Regular check-ups with healthcare professionals may include monitoring carotid artery health through ultrasound or other imaging techniques.

Computer-assisted image processing is a medical term that refers to the use of computer systems and specialized software to improve, analyze, and interpret medical images obtained through various imaging techniques such as X-ray, CT (computed tomography), MRI (magnetic resonance imaging), ultrasound, and others.

The process typically involves several steps, including image acquisition, enhancement, segmentation, restoration, and analysis. Image processing algorithms can be used to enhance the quality of medical images by adjusting contrast, brightness, and sharpness, as well as removing noise and artifacts that may interfere with accurate diagnosis. Segmentation techniques can be used to isolate specific regions or structures of interest within an image, allowing for more detailed analysis.

Computer-assisted image processing has numerous applications in medical imaging, including detection and characterization of lesions, tumors, and other abnormalities; assessment of organ function and morphology; and guidance of interventional procedures such as biopsies and surgeries. By automating and standardizing image analysis tasks, computer-assisted image processing can help to improve diagnostic accuracy, efficiency, and consistency, while reducing the potential for human error.

Carotid artery diseases refer to conditions that affect the carotid arteries, which are the major blood vessels that supply oxygen-rich blood to the head and neck. The most common type of carotid artery disease is atherosclerosis, which occurs when fatty deposits called plaques build up in the inner lining of the arteries.

These plaques can cause the arteries to narrow or become blocked, reducing blood flow to the brain and increasing the risk of stroke. Other carotid artery diseases include carotid artery dissection, which occurs when there is a tear in the inner lining of the artery, and fibromuscular dysplasia, which is a condition that affects the muscle and tissue in the walls of the artery.

Symptoms of carotid artery disease may include neck pain or pulsations, transient ischemic attacks (TIAs) or "mini-strokes," and strokes. Treatment options for carotid artery disease depend on the severity and type of the condition but may include lifestyle changes, medications, endarterectomy (a surgical procedure to remove plaque from the artery), or angioplasty and stenting (procedures to open blocked arteries using a balloon and stent).

I'm sorry for any confusion, but "Namibia" is not a medical term. It is the name of a country located in southern Africa, bordered by Angola and Zambia to the north, Botswana to the east, South Africa to the south and southeast, and the Atlantic Ocean to the west.

If you have any questions related to medical terminology or health-related topics, I would be happy to help answer them for you.

DNA replication is the biological process by which DNA makes an identical copy of itself during cell division. It is a fundamental mechanism that allows genetic information to be passed down from one generation of cells to the next. During DNA replication, each strand of the double helix serves as a template for the synthesis of a new complementary strand. This results in the creation of two identical DNA molecules. The enzymes responsible for DNA replication include helicase, which unwinds the double helix, and polymerase, which adds nucleotides to the growing strands.

X-ray computed tomography (CT or CAT scan) is a medical imaging method that uses computer-processed combinations of many X-ray images taken from different angles to produce cross-sectional (tomographic) images (virtual "slices") of the body. These cross-sectional images can then be used to display detailed internal views of organs, bones, and soft tissues in the body.

The term "computed tomography" is used instead of "CT scan" or "CAT scan" because the machines take a series of X-ray measurements from different angles around the body and then use a computer to process these data to create detailed images of internal structures within the body.

CT scanning is a noninvasive, painless medical test that helps physicians diagnose and treat medical conditions. CT imaging provides detailed information about many types of tissue including lung, bone, soft tissue and blood vessels. CT examinations can be performed on every part of the body for a variety of reasons including diagnosis, surgical planning, and monitoring of therapeutic responses.

In computed tomography (CT), an X-ray source and detector rotate around the patient, measuring the X-ray attenuation at many different angles. A computer uses this data to construct a cross-sectional image by the process of reconstruction. This technique is called "tomography". The term "computed" refers to the use of a computer to reconstruct the images.

CT has become an important tool in medical imaging and diagnosis, allowing radiologists and other physicians to view detailed internal images of the body. It can help identify many different medical conditions including cancer, heart disease, lung nodules, liver tumors, and internal injuries from trauma. CT is also commonly used for guiding biopsies and other minimally invasive procedures.

In summary, X-ray computed tomography (CT or CAT scan) is a medical imaging technique that uses computer-processed combinations of many X-ray images taken from different angles to produce cross-sectional images of the body. It provides detailed internal views of organs, bones, and soft tissues in the body, allowing physicians to diagnose and treat medical conditions.

Perceptual closure, also known as "closure perception" or "gestalt perception," is not a term that has a specific medical definition. It is a concept in the field of psychology and perception, particularly in gestalt psychology.

Perceptual closure refers to the ability of the brain to recognize and complete incomplete patterns or shapes by filling in the missing information based on context and past experiences. This allows us to perceive and understand complex stimuli even when they are partially occluded, distorted, or incomplete. It is a fundamental aspect of how we process visual information and helps us quickly and efficiently make sense of our environment.

While there may not be a specific medical definition for perceptual closure, deficits in this ability can have implications for various medical conditions, such as neurological disorders that affect vision or cognitive function.

Ultrasonography, also known as sonography, is a diagnostic medical procedure that uses high-frequency sound waves (ultrasound) to produce dynamic images of organs, tissues, or blood flow inside the body. These images are captured in real-time and can be used to assess the size, shape, and structure of various internal structures, as well as detect any abnormalities such as tumors, cysts, or inflammation.

During an ultrasonography procedure, a small handheld device called a transducer is placed on the patient's skin, which emits and receives sound waves. The transducer sends high-frequency sound waves into the body, and these waves bounce back off internal structures and are recorded by the transducer. The recorded data is then processed and transformed into visual images that can be interpreted by a medical professional.

Ultrasonography is a non-invasive, painless, and safe procedure that does not use radiation like other imaging techniques such as CT scans or X-rays. It is commonly used to diagnose and monitor conditions in various parts of the body, including the abdomen, pelvis, heart, blood vessels, and musculoskeletal system.

Carotid endarterectomy is a surgical procedure to remove plaque buildup (atherosclerosis) from the carotid arteries, which are the major blood vessels that supply oxygen-rich blood to the brain. The surgery involves making an incision in the neck, opening the carotid artery, and removing the plaque from the inside of the artery wall. The goal of the procedure is to restore normal blood flow to the brain and reduce the risk of stroke caused by the narrowing or blockage of the carotid arteries.

Nucleic acid amplification techniques (NAATs) are medical laboratory methods used to increase the number of copies of a specific DNA or RNA sequence. These techniques are widely used in molecular biology and diagnostics, including the detection and diagnosis of infectious diseases, genetic disorders, and cancer.

The most commonly used NAAT is the polymerase chain reaction (PCR), which involves repeated cycles of heating and cooling to separate and replicate DNA strands. Other NAATs include loop-mediated isothermal amplification (LAMP), nucleic acid sequence-based amplification (NASBA), and transcription-mediated amplification (TMA).

NAATs offer several advantages over traditional culture methods for detecting pathogens, including faster turnaround times, increased sensitivity and specificity, and the ability to detect viable but non-culturable organisms. However, they also require specialized equipment and trained personnel, and there is a risk of contamination and false positive results if proper precautions are not taken.

"T-lymphocyte gene rearrangement" refers to the process that occurs during the development of T-cells (a type of white blood cell) in which the genes that code for their antigen receptors are rearranged to create a unique receptor that can recognize and bind to specific foreign molecules, such as viruses or tumor cells.

The T-cell receptor (TCR) is made up of two chains, alpha and beta, which are composed of variable and constant regions. During gene rearrangement, the variable region genes are rearranged through a process called V(D)J recombination, in which specific segments of DNA are cut and joined together to form a unique combination that encodes for a diverse range of antigen receptors.

This allows T-cells to recognize and respond to a wide variety of foreign molecules, contributing to the adaptive immune response. However, this process can also lead to errors and the generation of T-cells with self-reactive receptors, which can contribute to autoimmune diseases if not properly regulated.

Contrast media are substances that are administered to a patient in order to improve the visibility of internal body structures or processes in medical imaging techniques such as X-rays, CT scans, MRI scans, and ultrasounds. These media can be introduced into the body through various routes, including oral, rectal, or intravenous administration.

Contrast media work by altering the appearance of bodily structures in imaging studies. For example, when a patient undergoes an X-ray examination, contrast media can be used to highlight specific organs, tissues, or blood vessels, making them more visible on the resulting images. In CT and MRI scans, contrast media can help to enhance the differences between normal and abnormal tissues, allowing for more accurate diagnosis and treatment planning.

There are several types of contrast media available, each with its own specific properties and uses. Some common examples include barium sulfate, which is used as a contrast medium in X-ray studies of the gastrointestinal tract, and iodinated contrast media, which are commonly used in CT scans to highlight blood vessels and other structures.

While contrast media are generally considered safe, they can sometimes cause adverse reactions, ranging from mild symptoms such as nausea or hives to more serious complications such as anaphylaxis or kidney damage. As a result, it is important for healthcare providers to carefully evaluate each patient's medical history and individual risk factors before administering contrast media.

A stroke, also known as cerebrovascular accident (CVA), is a serious medical condition that occurs when the blood supply to part of the brain is interrupted or reduced, leading to deprivation of oxygen and nutrients to brain cells. This can result in the death of brain tissue and cause permanent damage or temporary impairment to cognitive functions, speech, memory, movement, and other body functions controlled by the affected area of the brain.

Strokes can be caused by either a blockage in an artery that supplies blood to the brain (ischemic stroke) or the rupture of a blood vessel in the brain (hemorrhagic stroke). A transient ischemic attack (TIA), also known as a "mini-stroke," is a temporary disruption of blood flow to the brain that lasts only a few minutes and does not cause permanent damage.

Symptoms of a stroke may include sudden weakness or numbness in the face, arm, or leg; difficulty speaking or understanding speech; vision problems; loss of balance or coordination; severe headache with no known cause; and confusion or disorientation. Immediate medical attention is crucial for stroke patients to receive appropriate treatment and prevent long-term complications.

A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.

Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.

Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.

Viral DNA refers to the genetic material present in viruses that consist of DNA as their core component. Deoxyribonucleic acid (DNA) is one of the two types of nucleic acids that are responsible for storing and transmitting genetic information in living organisms. Viruses are infectious agents much smaller than bacteria that can only replicate inside the cells of other organisms, called hosts.

Viral DNA can be double-stranded (dsDNA) or single-stranded (ssDNA), depending on the type of virus. Double-stranded DNA viruses have a genome made up of two complementary strands of DNA, while single-stranded DNA viruses contain only one strand of DNA.

Examples of dsDNA viruses include Adenoviruses, Herpesviruses, and Poxviruses, while ssDNA viruses include Parvoviruses and Circoviruses. Viral DNA plays a crucial role in the replication cycle of the virus, encoding for various proteins necessary for its multiplication and survival within the host cell.

Single-stranded DNA (ssDNA) is a form of DNA that consists of a single polynucleotide chain. In contrast, double-stranded DNA (dsDNA) consists of two complementary polynucleotide chains that are held together by hydrogen bonds.

In the double-helix structure of dsDNA, each nucleotide base on one strand pairs with a specific base on the other strand through hydrogen bonding: adenine (A) with thymine (T), and guanine (G) with cytosine (C). This base pairing provides stability to the double-stranded structure.

Single-stranded DNA, on the other hand, lacks this complementary base pairing and is therefore less stable than dsDNA. However, ssDNA can still form secondary structures through intrastrand base pairing, such as hairpin loops or cruciform structures.

Single-stranded DNA is found in various biological contexts, including viral genomes, transcription bubbles during gene expression, and in certain types of genetic recombination. It also plays a critical role in some laboratory techniques, such as polymerase chain reaction (PCR) and DNA sequencing.

"Primed In Situ Labeling" (PRINS) is not a widely recognized medical term, but it is a technique used in molecular biology and pathology. Here's a definition of the PRINS technique:

Primed In Situ Labeling (PRINS) is a cytogenetic method that allows for the detection and visualization of specific DNA sequences within chromosomes or interphase nuclei through fluorescence in situ hybridization (FISH). The technique involves denaturing double-stranded DNA in fixed cells, followed by annealing a primer to a specific target sequence. A DNA polymerase then extends the primer, incorporating labeled nucleotides that can be visualized under a fluorescence microscope.

The PRINS technique offers several advantages over traditional FISH methods, including higher sensitivity and specificity, lower background signal, and the ability to analyze multiple targets simultaneously using different colored probes. It is commonly used in the diagnosis and monitoring of various genetic disorders, cancer, and infectious diseases.

Regional blood flow (RBF) refers to the rate at which blood flows through a specific region or organ in the body, typically expressed in milliliters per minute per 100 grams of tissue (ml/min/100g). It is an essential physiological parameter that reflects the delivery of oxygen and nutrients to tissues while removing waste products. RBF can be affected by various factors such as metabolic demands, neural regulation, hormonal influences, and changes in blood pressure or vascular resistance. Measuring RBF is crucial for understanding organ function, diagnosing diseases, and evaluating the effectiveness of treatments.

Nucleic acid conformation refers to the three-dimensional structure that nucleic acids (DNA and RNA) adopt as a result of the bonding patterns between the atoms within the molecule. The primary structure of nucleic acids is determined by the sequence of nucleotides, while the conformation is influenced by factors such as the sugar-phosphate backbone, base stacking, and hydrogen bonding.

Two common conformations of DNA are the B-form and the A-form. The B-form is a right-handed helix with a diameter of about 20 Å and a pitch of 34 Å, while the A-form has a smaller diameter (about 18 Å) and a shorter pitch (about 25 Å). RNA typically adopts an A-form conformation.

The conformation of nucleic acids can have significant implications for their function, as it can affect their ability to interact with other molecules such as proteins or drugs. Understanding the conformational properties of nucleic acids is therefore an important area of research in molecular biology and medicine.

Reference values, also known as reference ranges or reference intervals, are the set of values that are considered normal or typical for a particular population or group of people. These values are often used in laboratory tests to help interpret test results and determine whether a patient's value falls within the expected range.

The process of establishing reference values typically involves measuring a particular biomarker or parameter in a large, healthy population and then calculating the mean and standard deviation of the measurements. Based on these statistics, a range is established that includes a certain percentage of the population (often 95%) and excludes extreme outliers.

It's important to note that reference values can vary depending on factors such as age, sex, race, and other demographic characteristics. Therefore, it's essential to use reference values that are specific to the relevant population when interpreting laboratory test results. Additionally, reference values may change over time due to advances in measurement technology or changes in the population being studied.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Sensitivity and specificity are statistical measures used to describe the performance of a diagnostic test or screening tool in identifying true positive and true negative results.

* Sensitivity refers to the proportion of people who have a particular condition (true positives) who are correctly identified by the test. It is also known as the "true positive rate" or "recall." A highly sensitive test will identify most or all of the people with the condition, but may also produce more false positives.
* Specificity refers to the proportion of people who do not have a particular condition (true negatives) who are correctly identified by the test. It is also known as the "true negative rate." A highly specific test will identify most or all of the people without the condition, but may also produce more false negatives.

In medical testing, both sensitivity and specificity are important considerations when evaluating a diagnostic test. High sensitivity is desirable for screening tests that aim to identify as many cases of a condition as possible, while high specificity is desirable for confirmatory tests that aim to rule out the condition in people who do not have it.

It's worth noting that sensitivity and specificity are often influenced by factors such as the prevalence of the condition in the population being tested, the threshold used to define a positive result, and the reliability and validity of the test itself. Therefore, it's important to consider these factors when interpreting the results of a diagnostic test.

Superhelical DNA refers to a type of DNA structure that is formed when the double helix is twisted around itself. This occurs due to the presence of negative supercoiling, which results in an overtwisted state that can be described as having a greater number of helical turns than a relaxed circular DNA molecule.

Superhelical DNA is often found in bacterial and viral genomes, where it plays important roles in compacting the genome into a smaller volume and facilitating processes such as replication and transcription. The degree of supercoiling can affect the structure and function of DNA, with varying levels of supercoiling influencing the accessibility of specific regions of the genome to proteins and other regulatory factors.

Superhelical DNA is typically maintained in a stable state by topoisomerase enzymes, which introduce or remove twists in the double helix to regulate its supercoiling level. Changes in supercoiling can have significant consequences for cellular processes, as they can impact the expression of genes and the regulation of chromosome structure and function.

Closed-circuit anesthesia is a type of anesthesia delivery system in which the exhaled gases from the patient are rebreathed after being scrubbed of carbon dioxide and reoxygenated. This is different from open-circuit anesthesia, where the exhaled gases are vented out of the system and fresh gas is continuously supplied to the patient.

In a closed-circuit anesthesia system, the amount of anesthetic agent used can be more precisely controlled, which can lead to a reduction in overall drug usage and potentially fewer side effects for the patient. Additionally, because the exhaled gases are reused, there is less waste and a smaller environmental impact.

Closed-circuit anesthesia systems typically consist of a breathing system, an anesthetic vaporizer, a soda lime canister to remove carbon dioxide, a ventilator to assist with breathing if necessary, and monitors to track the patient's vital signs. These systems are commonly used in veterinary medicine and in human surgery where long-term anesthesia is required.

The thymus gland is an essential organ of the immune system, located in the upper chest, behind the sternum and surrounding the heart. It's primarily active until puberty and begins to shrink in size and activity thereafter. The main function of the thymus gland is the production and maturation of T-lymphocytes (T-cells), which are crucial for cell-mediated immunity, helping to protect the body from infection and cancer.

The thymus gland provides a protected environment where immune cells called pre-T cells develop into mature T cells. During this process, they learn to recognize and respond appropriately to foreign substances while remaining tolerant to self-tissues, which is crucial for preventing autoimmune diseases.

Additionally, the thymus gland produces hormones like thymosin that regulate immune cell activities and contribute to the overall immune response.

Genetic recombination is the process by which genetic material is exchanged between two similar or identical molecules of DNA during meiosis, resulting in new combinations of genes on each chromosome. This exchange occurs during crossover, where segments of DNA are swapped between non-sister homologous chromatids, creating genetic diversity among the offspring. It is a crucial mechanism for generating genetic variability and facilitating evolutionary change within populations. Additionally, recombination also plays an essential role in DNA repair processes through mechanisms such as homologous recombinational repair (HRR) and non-homologous end joining (NHEJ).

Bacteriophage phi X 174, also known as Phi X 174 or ΦX174, is a bacterial virus that infects the bacterium Escherichia coli (E. coli). It is a small, icosahedral-shaped virus with a diameter of about 30 nanometers and belongs to the family Podoviridae in the order Caudovirales.

Phi X 174 has a single-stranded DNA genome that is circular and consists of 5,386 base pairs. It is one of the smallest viruses known to infect bacteria, and its simplicity has made it a model system for studying bacteriophage biology and molecular biology.

Phi X 174 was first discovered in 1962 by American scientist S.E. Luria and his colleagues. It is able to infect E. coli cells that lack the F-pilus, a hair-like structure on the surface of the bacterial cell. Once inside the host cell, phi X 174 uses the host's machinery to replicate its DNA and produce new viral particles, which are then released from the host cell by lysis, causing the cell to burst open and release the new viruses.

Phi X 174 has been extensively studied for its unique biological properties, including its small size, simple genome, and ability to infect E. coli cells. It has also been used as a tool in molecular biology research, such as in the development of DNA sequencing techniques and the study of gene regulation.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Form perception, also known as shape perception, is not a term that has a specific medical definition. However, in the field of neuropsychology and sensory perception, form perception refers to the ability to recognize and interpret different shapes and forms of objects through visual processing. This ability is largely dependent on the integrity of the visual cortex and its ability to process and interpret information received from the retina.

Damage to certain areas of the brain, particularly in the occipital and parietal lobes, can result in deficits in form perception, leading to difficulties in recognizing and identifying objects based on their shape or form. This condition is known as visual agnosia and can be a symptom of various neurological disorders such as stroke, brain injury, or degenerative diseases like Alzheimer's disease.

Prospective studies, also known as longitudinal studies, are a type of cohort study in which data is collected forward in time, following a group of individuals who share a common characteristic or exposure over a period of time. The researchers clearly define the study population and exposure of interest at the beginning of the study and follow up with the participants to determine the outcomes that develop over time. This type of study design allows for the investigation of causal relationships between exposures and outcomes, as well as the identification of risk factors and the estimation of disease incidence rates. Prospective studies are particularly useful in epidemiology and medical research when studying diseases with long latency periods or rare outcomes.

Ciliary arteries are a type of ocular (eye) artery that originate from the posterior ciliary and muscular arteries. They supply blood to the ciliary body, choroid, and iris of the eye. The ciliary body is a part of the eye that contains muscles responsible for accommodation (the ability to focus on objects at different distances). The choroid is a layer of blood vessels that provides oxygen and nutrients to the outer layers of the retina. The iris is the colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil.

I'm sorry for any confusion, but "Gestalt Theory" is actually a concept in psychology, not medicine. It is a theory of perception that describes the way we organize visual elements into groups or unified wholes rather than processing them as individual parts. The term "Gestalt" is German for "form" or "shape."

In medical/healthcare fields, you might hear about Gestalt principles being used in areas like physical therapy, occupational therapy, or counseling to help patients make sense of their experiences or perceptions, but the theory itself is a concept from psychology.

Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).

In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.

In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.

REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.

Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.

The HIV Long Terminal Repeat (LTR) is a regulatory region of the human immunodeficiency virus (HIV) genome that contains important sequences necessary for the transcription and replication of the virus. The LTR is divided into several functional regions, including the U3, R, and U5 regions.

The U3 region contains various transcription factor binding sites that regulate the initiation of viral transcription. The R region contains a promoter element that helps to recruit the enzyme RNA polymerase II for the transcription process. The U5 region contains signals required for the proper processing and termination of viral RNA transcription.

The LTR plays a crucial role in the life cycle of HIV, as it is involved in the integration of the viral genome into the host cell's DNA, allowing the virus to persist and replicate within the infected cell. Understanding the function and regulation of the HIV LTR has been an important area of research in the development of HIV therapies and potential vaccines.

I'm sorry for any confusion, but "handwriting" is not a term that has a specific medical definition. Handwriting refers to the personal style or manner in which a person writes by hand. It can vary from person to person and can be influenced by factors such as an individual's fine motor skills, cultural background, and personal preferences.

However, in a broader context, there are certain medical conditions that can affect handwriting, such as neurological disorders (like stroke, Parkinson's disease, or cerebral palsy) or orthopedic issues (like arthritis or fractures). In these cases, healthcare professionals might assess a person's handwriting as part of the diagnostic process or to monitor the progression or treatment response of a condition. But again, handwriting itself is not a medical term with a specific definition.

Nucleic acid renaturation, also known as nucleic acid reassociation or hybridization, is the process of rejoining two complementary single-stranded nucleic acids (DNA or RNA) to form a double-stranded structure. This process occurs naturally in cells during transcription and DNA replication, but it can also be performed in vitro as a laboratory technique.

Renaturation typically involves denaturing the double-stranded nucleic acids into single strands by heat or chemical methods, followed by controlled cooling or modification of conditions to allow the complementary strands to find each other and reanneal. The rate and specificity of renaturation can be used to study the relatedness and concentration of nucleic acid sequences in a sample.

In molecular biology research, nucleic acid renaturation is often used in techniques such as Southern blotting, Northern blotting, and polymerase chain reaction (PCR) to detect and analyze specific DNA or RNA sequences.

Catenated DNA refers to the linking or interlocking of two or more DNA molecules in a circular form, where the circles are topologically entangled. This occurs during DNA replication when the sister chromatids (identical copies of DNA) are formed and remain interlinked before they are separated during cell division. The term "catenane" is used to describe this interlocking structure. It is important to note that in linear DNA, the term "catenated" does not apply since there is no circular formation.

Nucleic acid denaturation is the process of separating the two strands of a double-stranded DNA molecule, or unwinding the helical structure of an RNA molecule, by disrupting the hydrogen bonds that hold the strands together. This process is typically caused by exposure to high temperatures, changes in pH, or the presence of chemicals called denaturants.

Denaturation can also cause changes in the shape and function of nucleic acids. For example, it can disrupt the secondary and tertiary structures of RNA molecules, which can affect their ability to bind to other molecules and carry out their functions within the cell.

In molecular biology, nucleic acid denaturation is often used as a tool for studying the structure and function of nucleic acids. For example, it can be used to separate the two strands of a DNA molecule for sequencing or amplification, or to study the interactions between nucleic acids and other molecules.

It's important to note that denaturation is a reversible process, and under the right conditions, the double-stranded structure of DNA can be restored through a process called renaturation or annealing.

DNA nucleotidyltransferases are a class of enzymes that catalyze the addition of one or more nucleotides to the 3'-hydroxyl end of a DNA molecule. These enzymes play important roles in various biological processes, including DNA repair, recombination, and replication.

The reaction catalyzed by DNA nucleotidyltransferases involves the transfer of a nucleotide triphosphate (NTP) to the 3'-hydroxyl end of a DNA molecule, resulting in the formation of a phosphodiester bond and the release of pyrophosphate. The enzymes can add a single nucleotide or multiple nucleotides, depending on the specific enzyme and its function.

DNA nucleotidyltransferases are classified into several subfamilies based on their sequence similarity and function, including polymerases, terminal transferases, and primases. These enzymes have been extensively studied for their potential applications in biotechnology and medicine, such as in DNA sequencing, diagnostics, and gene therapy.

Repetitive sequences in nucleic acid refer to repeated stretches of DNA or RNA nucleotide bases that are present in a genome. These sequences can vary in length and can be arranged in different patterns such as direct repeats, inverted repeats, or tandem repeats. In some cases, these repetitive sequences do not code for proteins and are often found in non-coding regions of the genome. They can play a role in genetic instability, regulation of gene expression, and evolutionary processes. However, certain types of repeat expansions have been associated with various neurodegenerative disorders and other human diseases.

A telomere is a region of repetitive DNA sequences found at the end of chromosomes, which protects the genetic data from damage and degradation during cell division. Telomeres naturally shorten as cells divide, and when they become too short, the cell can no longer divide and becomes senescent or dies. This natural process is associated with aging and various age-related diseases. The length of telomeres can also be influenced by various genetic and environmental factors, including stress, diet, and lifestyle.

I'm sorry for any confusion, but "Solar System" is not a medical term. It refers to the astronomical system that includes our star, the Sun, and the objects that orbit it, such as planets, dwarf planets, asteroids, comets, and meteoroids. The Solar System is located in the Milky Way galaxy. If you have any medical terms or concepts you would like me to define or explain, I'd be happy to help!

Transposases are a type of enzyme that are involved in the process of transposition, which is the movement of a segment of DNA from one location within a genome to another. Transposases recognize and bind to specific sequences of DNA called inverted repeats that flank the mobile genetic element, or transposon, and catalyze the excision and integration of the transposon into a new location in the genome. This process can have significant consequences for the organization and regulation of genes within an organism's genome, and may contribute to genetic diversity and evolution.

Kluyveromyces is a genus of ascomycetous yeasts, which are commonly found in various environments such as plant material, food, and dairy products. These yeasts are often used in industrial applications, including the production of biofuels, enzymes, and single-cell proteins. Some species of Kluyveromyces have probiotic properties and can be found in the gastrointestinal tracts of animals and humans.

The genus Kluyveromyces is named after the Dutch microbiologist Albert J. Kluyver, who made significant contributions to the field of yeast research. The taxonomy of this genus has undergone several revisions, and some species previously classified as Kluyveromyces have been reassigned to other genera.

It is important to note that while Kluyveromyces species are generally considered safe for industrial use and human consumption, they can still cause infections in immunocompromised individuals or those with underlying medical conditions. Therefore, it is essential to handle these organisms with care and follow appropriate safety protocols when working with them.

Virus integration, in the context of molecular biology and virology, refers to the insertion of viral genetic material into the host cell's genome. This process is most commonly associated with retroviruses, such as HIV (Human Immunodeficiency Virus), which have an enzyme called reverse transcriptase that converts their RNA genome into DNA. This DNA can then integrate into the host's chromosomal DNA, becoming a permanent part of the host's genetic material.

This integration is a crucial step in the retroviral life cycle, allowing the virus to persist within the host cell and evade detection by the immune system. It also means that the viral genome can be passed on to daughter cells when the host cell divides.

However, it's important to note that not all viruses integrate their genetic material into the host's genome. Some viruses, like influenza, exist as separate entities within the host cell and do not become part of the host's DNA.

"Reagin" is an outdated term that was used to describe a type of antibody found in the blood serum of some individuals, particularly those who have had certain infectious diseases or who have allergies. These antibodies were known as "reaginic antibodies" and were characterized by their ability to cause a positive reaction in a test called the "Reagin test" or "Wassermann test."

The Reagin test was developed in the early 20th century and was used as a diagnostic tool for syphilis, a sexually transmitted infection caused by the bacterium Treponema pallidum. The test involved mixing a patient's serum with a suspension of cardiolipin, lecithin, and cholesterol - components derived from heart tissue. If reaginic antibodies were present in the patient's serum, they would bind to the cardiolipin component and form a complex that could be detected through a series of chemical reactions.

However, it was later discovered that reaginic antibodies were not specific to syphilis and could be found in individuals with other infectious diseases or allergies. As a result, the term "reagin" fell out of favor, and the test is no longer used as a diagnostic tool for syphilis. Instead, more specific and accurate tests, such as the Venereal Disease Research Laboratory (VDRL) test and the Treponema pallidum particle agglutination (TP-PA) assay, are now used to diagnose syphilis.

Virus replication is the process by which a virus produces copies or reproduces itself inside a host cell. This involves several steps:

1. Attachment: The virus attaches to a specific receptor on the surface of the host cell.
2. Penetration: The viral genetic material enters the host cell, either by invagination of the cell membrane or endocytosis.
3. Uncoating: The viral genetic material is released from its protective coat (capsid) inside the host cell.
4. Replication: The viral genetic material uses the host cell's machinery to produce new viral components, such as proteins and nucleic acids.
5. Assembly: The newly synthesized viral components are assembled into new virus particles.
6. Release: The newly formed viruses are released from the host cell, often through lysis (breaking) of the cell membrane or by budding off the cell membrane.

The specific mechanisms and details of virus replication can vary depending on the type of virus. Some viruses, such as DNA viruses, use the host cell's DNA polymerase to replicate their genetic material, while others, such as RNA viruses, use their own RNA-dependent RNA polymerase or reverse transcriptase enzymes. Understanding the process of virus replication is important for developing antiviral therapies and vaccines.

I'm sorry for any confusion, but "Nebraska" is a state in the central United States and not a medical term. If you have any medical questions or terms you would like defined, I'd be happy to help with those!

I'm sorry for any confusion, but "Stars, Celestial" is not a medical term. The term "stars" or "celestial bodies" is used in astronomy to refer to large, luminous spheres of plasma held together by gravity. They produce light and heat from the fusion of hydrogen into helium at their cores.

If you have any questions related to medical terminology, I'd be happy to help!

Size perception in a medical context typically refers to the way an individual's brain interprets and perceives the size or volume of various stimuli. This can include visual stimuli, such as objects or distances, as well as tactile stimuli, like the size of an object being held or touched.

Disorders in size perception can occur due to neurological conditions, brain injuries, or certain developmental disorders. For example, individuals with visual agnosia may have difficulty recognizing or perceiving the size of objects they see, even though their eyes are functioning normally. Similarly, those with somatoparaphrenia may not recognize the size of their own limbs due to damage in specific areas of the brain.

It's important to note that while 'size perception' is not a medical term per se, it can still be used in a medical or clinical context to describe these types of symptoms and conditions.

The Arctic region is not a medical term per se, but it is a geographical and environmental term that can have health-related implications. The Arctic is defined as the region surrounding the North Pole, encompassing the Arctic Ocean and parts of Canada, Greenland (Denmark), Russia, the United States (Alaska), Norway, Sweden, Finland, and Iceland. It is characterized by its cold climate, permafrost, and unique ecosystems.

Exposure to the harsh Arctic environment can pose significant health risks, such as hypothermia, frostbite, and other cold-related injuries. Additionally, the Arctic region has been impacted by climate change, leading to changes in the distribution of wildlife, which can have implications for food security and infectious disease transmission.

Therefore, while not a medical term itself, understanding the Arctic regions and their unique environmental and health challenges is important in fields such as wilderness medicine, environmental health, and public health.

Viroids are the smallest known pathogens that can infect plants. They are similar to viruses in that they consist of nucleic acid, but unlike viruses, viroids do not contain protein and are not encapsidated within a protective coat. Instead, viroids are simply small, naked circles of RNA that can replicate inside plant cells by using the host's enzymes.

Viroids can cause various diseases in plants, such as stunting, leaf distortion, and reduced yield. They can be transmitted through seed, vegetative propagation, or mechanical means, such as grafting or pruning tools. Because of their small size and simple structure, viroids are difficult to detect and control, making them a significant challenge in plant pathology.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

DNA helicases are a group of enzymes that are responsible for separating the two strands of DNA during processes such as replication and transcription. They do this by unwinding the double helix structure of DNA, using energy from ATP to break the hydrogen bonds between the base pairs. This allows other proteins to access the individual strands of DNA and carry out functions such as copying the genetic code or transcribing it into RNA.

During replication, DNA helicases help to create a replication fork, where the two strands of DNA are separated and new complementary strands are synthesized. In transcription, DNA helicases help to unwind the DNA double helix at the promoter region, allowing the RNA polymerase enzyme to bind and begin transcribing the DNA into RNA.

DNA helicases play a crucial role in maintaining the integrity of the genetic code and are essential for the normal functioning of cells. Defects in DNA helicases have been linked to various diseases, including cancer and neurological disorders.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

DNA restriction enzymes, also known as restriction endonucleases, are a type of enzyme that cut double-stranded DNA at specific recognition sites. These enzymes are produced by bacteria and archaea as a defense mechanism against foreign DNA, such as that found in bacteriophages (viruses that infect bacteria).

Restriction enzymes recognize specific sequences of nucleotides (the building blocks of DNA) and cleave the phosphodiester bonds between them. The recognition sites for these enzymes are usually palindromic, meaning that the sequence reads the same in both directions when facing the opposite strands of DNA.

Restriction enzymes are widely used in molecular biology research for various applications such as genetic engineering, genome mapping, and DNA fingerprinting. They allow scientists to cut DNA at specific sites, creating precise fragments that can be manipulated and analyzed. The use of restriction enzymes has been instrumental in the development of recombinant DNA technology and the Human Genome Project.

DNA ligases are enzymes that catalyze the formation of a phosphodiester bond between two compatible ends of DNA molecules, effectively joining or "ligating" them together. There are several types of DNA ligases found in nature, each with specific functions and preferences for the type of DNA ends they can seal.

The most well-known DNA ligase is DNA ligase I, which plays a crucial role in replicating and repairing DNA in eukaryotic cells. It seals nicks or gaps in double-stranded DNA during replication and participates in the final step of DNA excision repair by rejoining the repaired strand to the original strand.

DNA ligase IV, another important enzyme, is primarily involved in the repair of double-strand breaks through a process called non-homologous end joining (NHEJ). This pathway is essential for maintaining genome stability and preventing chromosomal abnormalities.

Bacterial DNA ligases, such as T4 DNA ligase, are often used in molecular biology techniques due to their ability to join various types of DNA ends with high efficiency. These enzymes have been instrumental in the development of recombinant DNA technology and gene cloning methods.

A replication origin is a specific location in a DNA molecule where the process of DNA replication is initiated. It serves as the starting point for the synthesis of new strands of DNA during cell division. The origin of replication contains regulatory elements and sequences that are recognized by proteins, which then recruit and assemble the necessary enzymes to start the replication process. In eukaryotic cells, replication origins are often found in clusters, with multiple origins scattered throughout each chromosome.

Fungal DNA refers to the genetic material present in fungi, which are a group of eukaryotic organisms that include microorganisms such as yeasts and molds, as well as larger organisms like mushrooms. The DNA of fungi, like that of all living organisms, is made up of nucleotides that are arranged in a double helix structure.

Fungal DNA contains the genetic information necessary for the growth, development, and reproduction of fungi. This includes the instructions for making proteins, which are essential for the structure and function of cells, as well as other important molecules such as enzymes and nucleic acids.

Studying fungal DNA can provide valuable insights into the biology and evolution of fungi, as well as their potential uses in medicine, agriculture, and industry. For example, researchers have used genetic engineering techniques to modify the DNA of fungi to produce drugs, biofuels, and other useful products. Additionally, understanding the genetic makeup of pathogenic fungi can help scientists develop new strategies for preventing and treating fungal infections.

Visual pattern recognition is the ability to identify and interpret patterns in visual information. In a medical context, it often refers to the process by which healthcare professionals recognize and diagnose medical conditions based on visible signs or symptoms. This can involve recognizing the characteristic appearance of a rash, wound, or other physical feature associated with a particular disease or condition. It may also involve recognizing patterns in medical images such as X-rays, CT scans, or MRIs.

In the field of radiology, for example, visual pattern recognition is a critical skill. Radiologists are trained to recognize the typical appearances of various diseases and conditions in medical images. This allows them to make accurate diagnoses based on the patterns they see. Similarly, dermatologists use visual pattern recognition to identify skin abnormalities and diseases based on the appearance of rashes, lesions, or other skin changes.

Overall, visual pattern recognition is an essential skill in many areas of medicine, allowing healthcare professionals to quickly and accurately diagnose medical conditions based on visible signs and symptoms.

Bacillus phages are viruses that infect and replicate within bacteria of the genus Bacillus. These phages, also known as bacteriophages or simply phages, are a type of virus that is specifically adapted to infect and multiply within bacteria. They use the bacterial cell's machinery to produce new copies of themselves, often resulting in the lysis (breakdown) of the bacterial cell. Bacillus phages are widely studied for their potential applications in biotechnology, medicine, and basic research.

I'm sorry for any confusion, but "Hospital Bed Capacity, 500 and over" is not a medical term or concept itself. However, I can provide some context related to hospital bed capacity in general.

Hospital bed capacity refers to the total number of beds that are available for patients in a healthcare facility. This includes both regular beds and any specialized beds, such as intensive care unit (ICU) beds.

When we say "500 and over," it's simply indicating a threshold for the size of the hospital. A hospital with a bed capacity of 500 or more is considered a large hospital. This can have implications for the range of services offered, the complexity of cases handled, and the resources available. However, it doesn't change the basic definition or nature of what a hospital bed capacity is.

I hope this helps! If you have any other questions about medical definitions or concepts, feel free to ask.

Reverse transcription is the enzymatic process by which an RNA molecule is copied into a DNA sequence. This process is performed by the reverse transcriptase enzyme, which synthesizes a complementary DNA (cDNA) strand using the RNA as a template. Reverse transcription occurs naturally in retroviruses, such as HIV, where it allows the viral RNA genome to be integrated into the host cell's DNA. This mechanism is also used in molecular biology techniques like cDNA cloning and gene expression analysis.

DNA transposable elements, also known as transposons or jumping genes, are mobile genetic elements that can change their position within a genome. They are composed of DNA sequences that include genes encoding the enzymes required for their own movement (transposase) and regulatory elements. When activated, the transposase recognizes specific sequences at the ends of the element and catalyzes the excision and reintegration of the transposable element into a new location in the genome. This process can lead to genetic variation, as the insertion of a transposable element can disrupt the function of nearby genes or create new combinations of gene regulatory elements. Transposable elements are widespread in both prokaryotic and eukaryotic genomes and are thought to play a significant role in genome evolution.

Electromagnetic radiation (EMR) is a type of energy that is released and transferred through space in the form of waves. These waves are characterized by their wavelength, frequency, and speed, all of which determine the amount of energy they carry. Elemagnetic radiation is classified into different types based on its wavelength and frequency, including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

EMR is produced by the movement of charged particles, such as electrons, and can be both natural and artificial in origin. For example, the sun emits EMR in the form of visible light and ultraviolet radiation, while man-made sources of EMR include cell phones, WiFi routers, and medical imaging equipment.

In medicine, EMR is used for a variety of purposes, including diagnostic imaging, cancer treatment, and sterilization. For example, X-rays and CT scans use high-energy forms of EMR to produce images of the body's internal structures, while radiation therapy uses targeted beams of EMR to destroy cancer cells.

It is important to note that excessive exposure to certain types of EMR, particularly ionizing radiation such as X-rays and gamma rays, can be harmful to human health and may increase the risk of cancer and other diseases. Therefore, it is essential to use appropriate safety measures when working with or around sources of EMR.

Extrachromosomal inheritance refers to the transmission of genetic information that occurs outside of the chromosomes, which are the structures in the cell nucleus that typically contain and transmit genetic material. This type of inheritance is relatively rare and can involve various types of genetic elements, such as plasmids or transposons.

In extrachromosomal inheritance, these genetic elements can replicate independently of the chromosomes and be passed on to offspring through mechanisms other than traditional Mendelian inheritance. This can lead to non-Mendelian patterns of inheritance, where traits do not follow the expected dominant or recessive patterns.

One example of extrachromosomal inheritance is the transmission of mitochondrial DNA (mtDNA), which occurs in the cytoplasm of the cell rather than on the chromosomes. Mitochondria are organelles that produce energy for the cell, and they contain their own small circular genome that is inherited maternally. Mutations in mtDNA can lead to a variety of genetic disorders, including mitochondrial diseases.

Overall, extrachromosomal inheritance is an important area of study in genetics, as it can help researchers better understand the complex ways in which genetic information is transmitted and expressed in living organisms.

Molecular probe techniques are analytical methods used in molecular biology and medicine to detect, analyze, and visualize specific biological molecules or cellular structures within cells, tissues, or bodily fluids. These techniques typically involve the use of labeled probes that bind selectively to target molecules, allowing for their detection and quantification.

A molecular probe is a small molecule or biomacromolecule (such as DNA, RNA, peptide, or antibody) that has been tagged with a detectable label, such as a fluorescent dye, radioisotope, enzyme, or magnetic particle. The probe is designed to recognize and bind to a specific target molecule, such as a gene, protein, or metabolite, through complementary base pairing, antigen-antibody interactions, or other forms of molecular recognition.

Molecular probe techniques can be broadly classified into two categories:

1. In situ hybridization (ISH): This technique involves the use of labeled DNA or RNA probes to detect specific nucleic acid sequences within cells or tissues. The probes are designed to complement the target sequence and, upon hybridization, allow for the visualization of the location and quantity of the target molecule using various detection methods, such as fluorescence microscopy, brightfield microscopy, or radioisotopic imaging.
2. Immunohistochemistry (IHC) and immunofluorescence (IF): These techniques utilize antibodies as probes to detect specific proteins within cells or tissues. Primary antibodies are raised against a target protein and, upon binding, can be detected using various methods, such as enzyme-linked secondary antibodies, fluorescent dyes, or gold nanoparticles. IHC is typically used for brightfield microscopy, while IF is used for fluorescence microscopy.

Molecular probe techniques have numerous applications in basic research, diagnostics, and therapeutics, including gene expression analysis, protein localization, disease diagnosis, drug development, and targeted therapy.

Crithidia is a genus of protozoan parasites belonging to the family Trypanosomatidae. These parasites are primarily found in the digestive tracts of insects, particularly blood-sucking insects such as mosquitoes and reduviid bugs. They are transmitted to the insect through the ingestion of infected prey, such as other insects.

Crithidia species are closely related to Trypanosoma species, which can cause serious diseases in humans and animals, such as sleeping sickness and Chagas disease. However, Crithidia species are not typically considered to be human pathogens, although there have been rare cases of human infection reported in the literature.

In general, Crithidia species are studied for their potential use as model organisms in research on topics such as evolution, genetics, and cell biology. They are also used in forensic entomology to help estimate the postmortem interval (PMI) in cases of insect-associated death investigations.

The optic disk, also known as the optic nerve head, is the point where the optic nerve fibers exit the eye and transmit visual information to the brain. It appears as a pale, circular area in the back of the eye, near the center of the retina. The optic disk has no photoreceptor cells (rods and cones), so it is insensitive to light. It is an important structure to observe during eye examinations because changes in its appearance can indicate various ocular diseases or conditions, such as glaucoma, optic neuritis, or papilledema.

1. Receptors: In the context of physiology and medicine, receptors are specialized proteins found on the surface of cells or inside cells that detect and respond to specific molecules, known as ligands. These interactions can trigger a range of responses within the cell, such as starting a signaling pathway or changing the cell's behavior. There are various types of receptors, including ion channels, G protein-coupled receptors, and enzyme-linked receptors.

2. Antigen: An antigen is any substance (usually a protein) that can be recognized by the immune system, specifically by antibodies or T-cells, as foreign and potentially harmful. Antigens can be derived from various sources, such as bacteria, viruses, fungi, parasites, or even non-living substances like pollen, chemicals, or toxins. An antigen typically contains epitopes, which are the specific regions that antibodies or T-cell receptors recognize and bind to.

3. T-Cell: Also known as T lymphocytes, T-cells are a type of white blood cell that plays a crucial role in cell-mediated immunity, a part of the adaptive immune system. They are produced in the bone marrow and mature in the thymus gland. There are several types of T-cells, including CD4+ helper T-cells, CD8+ cytotoxic T-cells, and regulatory T-cells (Tregs). T-cells recognize antigens presented to them by antigen-presenting cells (APCs) via their surface receptors called the T-cell receptor (TCR). Once activated, T-cells can proliferate and differentiate into various effector cells that help eliminate infected or damaged cells.

Bacterial DNA refers to the genetic material found in bacteria. It is composed of a double-stranded helix containing four nucleotide bases - adenine (A), thymine (T), guanine (G), and cytosine (C) - that are linked together by phosphodiester bonds. The sequence of these bases in the DNA molecule carries the genetic information necessary for the growth, development, and reproduction of bacteria.

Bacterial DNA is circular in most bacterial species, although some have linear chromosomes. In addition to the main chromosome, many bacteria also contain small circular pieces of DNA called plasmids that can carry additional genes and provide resistance to antibiotics or other environmental stressors.

Unlike eukaryotic cells, which have their DNA enclosed within a nucleus, bacterial DNA is present in the cytoplasm of the cell, where it is in direct contact with the cell's metabolic machinery. This allows for rapid gene expression and regulation in response to changing environmental conditions.

Nerve fibers are specialized structures that constitute the long, slender processes (axons) of neurons (nerve cells). They are responsible for conducting electrical impulses, known as action potentials, away from the cell body and transmitting them to other neurons or effector organs such as muscles and glands. Nerve fibers are often surrounded by supportive cells called glial cells and are grouped together to form nerve bundles or nerves. These fibers can be myelinated (covered with a fatty insulating sheath called myelin) or unmyelinated, which influences the speed of impulse transmission.

Severe Combined Immunodeficiency (SCID) is a group of rare genetic disorders characterized by deficient or absent immune responses. It results from mutations in different genes involved in the development and function of T lymphocytes, B lymphocytes, or both, leading to a severe impairment in cell-mediated and humoral immunity.

Infants with SCID are extremely vulnerable to infections, which can be life-threatening. Common symptoms include chronic diarrhea, failure to thrive, recurrent pneumonia, and persistent candidiasis (thrush). If left untreated, it can lead to severe disability or death within the first two years of life. Treatment typically involves bone marrow transplantation or gene therapy to restore immune function.

I'm sorry for any confusion, but "South Dakota" is not a medical term or concept. It is a geographical location, being one of the 50 states in the United States of America. If you have any questions related to medical topics, I would be happy to try and help answer those for you!

DNA-directed DNA polymerase is a type of enzyme that synthesizes new strands of DNA by adding nucleotides to an existing DNA template in a 5' to 3' direction. These enzymes are essential for DNA replication, repair, and recombination. They require a single-stranded DNA template, a primer with a free 3' hydroxyl group, and the four deoxyribonucleoside triphosphates (dNTPs) as substrates to carry out the polymerization reaction.

DNA polymerases also have proofreading activity, which allows them to correct errors that occur during DNA replication by removing mismatched nucleotides and replacing them with the correct ones. This helps ensure the fidelity of the genetic information passed from one generation to the next.

There are several different types of DNA polymerases, each with specific functions and characteristics. For example, DNA polymerase I is involved in both DNA replication and repair, while DNA polymerase III is the primary enzyme responsible for DNA replication in bacteria. In eukaryotic cells, DNA polymerase alpha, beta, gamma, delta, and epsilon have distinct roles in DNA replication, repair, and maintenance.

A genetic template refers to the sequence of DNA or RNA that contains the instructions for the development and function of an organism or any of its components. These templates provide the code for the synthesis of proteins and other functional molecules, and determine many of the inherited traits and characteristics of an individual. In this sense, genetic templates serve as the blueprint for life and are passed down from one generation to the next through the process of reproduction.

In molecular biology, the term "template" is used to describe the strand of DNA or RNA that serves as a guide or pattern for the synthesis of a complementary strand during processes such as transcription and replication. During transcription, the template strand of DNA is transcribed into a complementary RNA molecule, while during replication, each parental DNA strand serves as a template for the synthesis of a new complementary strand.

In genetic engineering and synthetic biology, genetic templates can be manipulated and modified to introduce new functions or alter existing ones in organisms. This is achieved through techniques such as gene editing, where specific sequences in the genetic template are targeted and altered using tools like CRISPR-Cas9. Overall, genetic templates play a crucial role in shaping the structure, function, and evolution of all living organisms.

RNA (Ribonucleic Acid) is a single-stranded, linear polymer of ribonucleotides. It is a nucleic acid present in the cells of all living organisms and some viruses. RNAs play crucial roles in various biological processes such as protein synthesis, gene regulation, and cellular signaling. There are several types of RNA including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), microRNA (miRNA), and long non-coding RNA (lncRNA). These RNAs differ in their structure, function, and location within the cell.

Electrophoresis, Agar Gel is a laboratory technique used to separate and analyze DNA, RNA, or proteins based on their size and electrical charge. In this method, the sample is mixed with agarose gel, a gelatinous substance derived from seaweed, and then solidified in a horizontal slab-like format. An electric field is applied to the gel, causing the negatively charged DNA or RNA molecules to migrate towards the positive electrode. The smaller molecules move faster through the gel than the larger ones, resulting in their separation based on size. This technique is widely used in molecular biology and genetics research, as well as in diagnostic testing for various genetic disorders.

Optical illusions are visual phenomena that occur when the brain perceives an image or scene differently from the actual physical properties of that image or scene. They often result from the brain's attempt to interpret and make sense of ambiguous, contradictory, or incomplete information provided by the eyes. This can lead to visually perceived images that are different from the objective reality. Optical illusions can be categorized into different types such as literal illusions, physiological illusions, and cognitive illusions, based on the nature of the illusion and the underlying cause.

Photic stimulation is a medical term that refers to the exposure of the eyes to light, specifically repetitive pulses of light, which is used as a method in various research and clinical settings. In neuroscience, it's often used in studies related to vision, circadian rhythms, and brain function.

In a clinical context, photic stimulation is sometimes used in the diagnosis of certain medical conditions such as seizure disorders (like epilepsy). By observing the response of the brain to this light stimulus, doctors can gain valuable insights into the functioning of the brain and the presence of any neurological disorders.

However, it's important to note that photic stimulation should be conducted under the supervision of a trained healthcare professional, as improper use can potentially trigger seizures in individuals who are susceptible to them.

In a medical context, "orientation" typically refers to an individual's awareness and understanding of their personal identity, place, time, and situation. It is a critical component of cognitive functioning and mental status. Healthcare professionals often assess a person's orientation during clinical evaluations, using tests that inquire about their name, location, the current date, and the circumstances of their hospitalization or visit.

There are different levels of orientation:

1. Person (or self): The individual knows their own identity, including their name, age, and other personal details.
2. Place: The individual is aware of where they are, such as the name of the city, hospital, or healthcare facility.
3. Time: The individual can accurately state the current date, day of the week, month, and year.
4. Situation or event: The individual understands why they are in the healthcare setting, what happened leading to their hospitalization or visit, and the nature of any treatments or procedures they are undergoing.

Impairments in orientation can be indicative of various neurological or psychiatric conditions, such as delirium, dementia, or substance intoxication or withdrawal. It is essential for healthcare providers to monitor and address orientation issues to ensure appropriate diagnosis, treatment, and patient safety.

HIV-1 (Human Immunodeficiency Virus type 1) is a species of the retrovirus genus that causes acquired immunodeficiency syndrome (AIDS). It is primarily transmitted through sexual contact, exposure to infected blood or blood products, and from mother to child during pregnancy, childbirth, or breastfeeding. HIV-1 infects vital cells in the human immune system, such as CD4+ T cells, macrophages, and dendritic cells, leading to a decline in their numbers and weakening of the immune response over time. This results in the individual becoming susceptible to various opportunistic infections and cancers that ultimately cause death if left untreated. HIV-1 is the most prevalent form of HIV worldwide and has been identified as the causative agent of the global AIDS pandemic.

Coliphages are viruses that infect and replicate within certain species of bacteria that belong to the coliform group, particularly Escherichia coli (E. coli). These viruses are commonly found in water and soil environments and are frequently used as indicators of fecal contamination in water quality testing. Coliphages are not harmful to humans or animals, but their presence in water can suggest the potential presence of pathogenic bacteria or other microorganisms that may pose a health risk. There are two main types of coliphages: F-specific RNA coliphages and somatic (or non-F specific) DNA coliphages.

DNA-binding proteins are a type of protein that have the ability to bind to DNA (deoxyribonucleic acid), the genetic material of organisms. These proteins play crucial roles in various biological processes, such as regulation of gene expression, DNA replication, repair and recombination.

The binding of DNA-binding proteins to specific DNA sequences is mediated by non-covalent interactions, including electrostatic, hydrogen bonding, and van der Waals forces. The specificity of binding is determined by the recognition of particular nucleotide sequences or structural features of the DNA molecule.

DNA-binding proteins can be classified into several categories based on their structure and function, such as transcription factors, histones, and restriction enzymes. Transcription factors are a major class of DNA-binding proteins that regulate gene expression by binding to specific DNA sequences in the promoter region of genes and recruiting other proteins to modulate transcription. Histones are DNA-binding proteins that package DNA into nucleosomes, the basic unit of chromatin structure. Restriction enzymes are DNA-binding proteins that recognize and cleave specific DNA sequences, and are widely used in molecular biology research and biotechnology applications.

Terminal repeat sequences (TRS) are repetitive DNA sequences that are located at the termini or ends of chromosomes, plasmids, and viral genomes. They play a significant role in various biological processes such as genome replication, packaging, and integration. In eukaryotic cells, telomeres are the most well-known TRS, which protect the chromosome ends from degradation, fusion, and other forms of DNA damage.

Telomeres consist of repetitive DNA sequences (5'-TTAGGG-3' in vertebrates) that are several kilobases long, associated with a set of shelterin proteins that protect them from being recognized as double-strand breaks by the DNA repair machinery. With each cell division, telomeres progressively shorten due to the end replication problem, which can ultimately lead to cellular senescence or apoptosis.

In contrast, prokaryotic TRS are often found at the ends of plasmids and phages and are involved in DNA replication, packaging, and integration into host genomes. For example, the attP and attB sites in bacteriophage lambda are TRS that facilitate site-specific recombination during integration and excision from the host genome.

Overall, terminal repeat sequences are essential for maintaining genome stability and integrity in various organisms, and their dysfunction can lead to genomic instability, disease, and aging.

A DNA probe is a single-stranded DNA molecule that contains a specific sequence of nucleotides, and is labeled with a detectable marker such as a radioisotope or a fluorescent dye. It is used in molecular biology to identify and locate a complementary sequence within a sample of DNA. The probe hybridizes (forms a stable double-stranded structure) with its complementary sequence through base pairing, allowing for the detection and analysis of the target DNA. This technique is widely used in various applications such as genetic testing, diagnosis of infectious diseases, and forensic science.

DNA topoisomerases are enzymes that modify the topological structure of DNA by regulating the number of twists or supercoils in the double helix. There are two main types of DNA topoisomerases: type I and type II.

Type I DNA topoisomerases function by cutting one strand of the DNA duplex, allowing the uncut strand to rotate around the break, and then resealing the break. This process can relieve both positive and negative supercoiling in DNA, as well as introduce single-stranded breaks into the DNA molecule.

Type I topoisomerases are further divided into three subtypes: type IA, type IB, and type IC. These subtypes differ in their mechanism of action and the structure of the active site tyrosine residue that makes the transient break in the DNA strand.

Overall, DNA topoisomerases play a crucial role in many cellular processes involving DNA, including replication, transcription, recombination, and chromosome segregation. Dysregulation of these enzymes has been implicated in various human diseases, including cancer and genetic disorders.

I apologize for any confusion, but "Malvaceae" is not a medical term. It is a taxonomic category in botany, referring to the mallow family of plants, which includes over 4,000 species. Some plants in this family have been used in traditional medicine, but Malvaceae itself does not have a specific medical definition.

Psychophysics is not a medical term per se, but rather a subfield of psychology and neuroscience that studies the relationship between physical stimuli and the sensations and perceptions they produce. It involves the quantitative investigation of psychological functions, such as how brightness or loudness is perceived relative to the physical intensity of light or sound.

In medical contexts, psychophysical methods may be used in research or clinical settings to understand how patients with neurological conditions or sensory impairments perceive and respond to different stimuli. This information can inform diagnostic assessments, treatment planning, and rehabilitation strategies.

Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific regions of DNA. It enables the production of thousands to millions of copies of a particular DNA sequence in a rapid and efficient manner, making it an essential tool in various fields such as molecular biology, medical diagnostics, forensic science, and research.

The PCR process involves repeated cycles of heating and cooling to separate the DNA strands, allow primers (short sequences of single-stranded DNA) to attach to the target regions, and extend these primers using an enzyme called Taq polymerase, resulting in the exponential amplification of the desired DNA segment.

In a medical context, PCR is often used for detecting and quantifying specific pathogens (viruses, bacteria, fungi, or parasites) in clinical samples, identifying genetic mutations or polymorphisms associated with diseases, monitoring disease progression, and evaluating treatment effectiveness.

"Saccharomyces cerevisiae" is not typically considered a medical term, but it is a scientific name used in the field of microbiology. It refers to a species of yeast that is commonly used in various industrial processes, such as baking and brewing. It's also widely used in scientific research due to its genetic tractability and eukaryotic cellular organization.

However, it does have some relevance to medical fields like medicine and nutrition. For example, certain strains of S. cerevisiae are used as probiotics, which can provide health benefits when consumed. They may help support gut health, enhance the immune system, and even assist in the digestion of certain nutrients.

In summary, "Saccharomyces cerevisiae" is a species of yeast with various industrial and potential medical applications.

Deoxyribonucleoproteins are complexes formed by the association of DNA (deoxyribonucleic acid) with proteins. These complexes play a crucial role in various cellular processes, including the packaging and protection of DNA within the cell, as well as the regulation of gene expression.

In particular, deoxyribonucleoproteins are important components of chromatin, which is the material that makes up chromosomes. Histone proteins are among the most abundant proteins found in chromatin, and they play a key role in compacting DNA into a more condensed form. Other non-histone proteins also associate with DNA to regulate various cellular processes, such as transcription, replication, and repair.

Deoxyribonucleoproteins can also be found in viruses, where they are often referred to as nucleocapsids. In these cases, the deoxyribonucleoprotein complex serves to protect the viral genome and facilitate its replication and transmission between host cells.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Optical coherence tomography (OCT) is a non-invasive imaging technique that uses low-coherence light to capture high-resolution cross-sectional images of biological tissues, particularly the retina and other ocular structures. OCT works by measuring the echo time delay of light scattered back from different depths within the tissue, creating a detailed map of the tissue's structure. This technique is widely used in ophthalmology to diagnose and monitor various eye conditions such as macular degeneration, diabetic retinopathy, and glaucoma.

In the context of medicine and healthcare, "movement" refers to the act or process of changing physical location or position. It involves the contraction and relaxation of muscles, which allows for the joints to move and the body to be in motion. Movement can also refer to the ability of a patient to move a specific body part or limb, which is assessed during physical examinations. Additionally, "movement" can describe the progression or spread of a disease within the body.

Corrosion casting is a specialized technique used in anatomy and pathology to create detailed casts or molds of biological specimens, particularly vascular systems. This method is also known as "acid etching" or "corrosive casting." Here's the medical definition:

Corrosion casting is a process that involves injecting a special resin or plastic material into the vasculature or other hollow structures of a biological specimen, such as an organ or tissue. The injected material thoroughly fills the cavity and then hardens once it has set. After hardening, the surrounding tissues are corroded or dissolved using strong acids or bases, leaving behind only the cast or mold of the internal structures.

This technique results in a detailed three-dimensional representation of the complex internal networks, like blood vessels, which can be used for further study, research, and education. Corrosion casting is particularly useful in visualizing the intricate branching patterns and structural relationships within these systems.

T-cell receptors (TCRs) are proteins found on the surface of T cells, which are a type of white blood cell in the immune system. They play a critical role in adaptive immunity, allowing T cells to recognize and respond to specific targets such as infected or cancerous cells.

A gene is a segment of DNA that contains the instructions for making a particular protein. In the case of TCRs, there are two types of genes involved: TCR alpha (TRAV) and TCR beta (TRB) genes. These genes are located in a region of the human genome called the T-cell receptor locus.

During T-cell development, a process called V(D)J recombination occurs, which randomly assembles different segments of the TRAV and TRB genes to create a unique TCR alpha and TCR beta chain, respectively. This results in a vast diversity of TCRs, allowing the immune system to recognize a wide variety of targets.

The assembled TCR alpha and beta chains then form a heterodimer that is expressed on the surface of the T cell. When a TCR recognizes its specific target, it triggers a series of events that ultimately leads to the destruction of the targeted cell.

An oligonucleotide probe is a short, single-stranded DNA or RNA molecule that contains a specific sequence of nucleotides designed to hybridize with a complementary sequence in a target nucleic acid (DNA or RNA). These probes are typically 15-50 nucleotides long and are used in various molecular biology techniques, such as polymerase chain reaction (PCR), DNA sequencing, microarray analysis, and blotting methods.

Oligonucleotide probes can be labeled with various reporter molecules, like fluorescent dyes or radioactive isotopes, to enable the detection of hybridized targets. The high specificity of oligonucleotide probes allows for the precise identification and quantification of target nucleic acids in complex biological samples, making them valuable tools in diagnostic, research, and forensic applications.

I'm sorry for any confusion, but "rain" is not a medical term. In general, rain refers to water droplets that fall from the sky as part of the Earth's weather cycle. These drops form when moisture in the air condenses and cools, creating clouds which eventually become heavy enough to release the collected water.

If you have any medical concerns or questions, I'd be happy to try and help answer those for you!

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

The Immunoglobulin (Ig) switch region, also known as the switch (S) region or switch area, is a segment of DNA located within the heavy chain constant region (Cμ, Cδ, Cγ, Cε, and Cα) genes of the immunoglobulin locus. These regions are found in chromosome 14 in humans.

The Ig switch regions are crucial for antibody class switching, a process that allows B cells to change the type of heavy chain constant region (Cμ, Cδ, Cγ, Cε, or Cα) expressed in their immunoglobulin, thus modifying the effector functions of the antibodies they produce without altering their antigen specificity. This mechanism enables the immune system to generate a more diverse response against various pathogens and adapt to new challenges.

The switch regions are composed of repetitive DNA sequences that vary in length and sequence between different immunoglobulin isotypes (IgM, IgD, IgG, IgA, and IgE). During class switching, an activated B cell utilizes the enzyme activation-induced cytidine deaminase (AID) to introduce DNA double-strand breaks within a specific switch region. The broken ends of the DNA are then joined together through a process called class switch recombination (CSR), resulting in the deletion of the intervening DNA and the fusion of the upstream V(D)J region with a new downstream constant region gene, thereby altering the isotype of the expressed antibody.

Leishmania is a genus of protozoan parasites that are the causative agents of Leishmaniasis, a group of diseases with various clinical manifestations. These parasites are transmitted to humans through the bite of infected female phlebotomine sandflies. The disease has a wide geographic distribution, mainly in tropical and subtropical regions, including parts of Asia, Africa, South America, and Southern Europe.

The Leishmania species have a complex life cycle that involves two main stages: the promastigote stage, which is found in the sandfly vector, and the amastigote stage, which infects mammalian hosts, including humans. The clinical manifestations of Leishmaniasis depend on the specific Leishmania species and the host's immune response to the infection.

The three main forms of Leishmaniasis are:

1. Cutaneous Leishmaniasis (CL): This form is characterized by skin lesions, such as ulcers or nodules, that can take several months to heal and may leave scars. CL is caused by various Leishmania species, including L. major, L. tropica, and L. aethiopica.

2. Visceral Leishmaniasis (VL): Also known as kala-azar, VL affects internal organs such as the spleen, liver, and bone marrow. Symptoms include fever, weight loss, anemia, and enlarged liver and spleen. VL is caused by L. donovani, L. infantum, and L. chagasi species.

3. Mucocutaneous Leishmaniasis (MCL): This form affects the mucous membranes of the nose, mouth, and throat, causing destruction of tissues and severe disfigurement. MCL is caused by L. braziliensis and L. guyanensis species.

Prevention and control measures for Leishmaniasis include vector control, early diagnosis and treatment, and protection against sandfly bites through the use of insect repellents and bed nets.

Mitochondrial DNA (mtDNA) is the genetic material present in the mitochondria, which are specialized structures within cells that generate energy. Unlike nuclear DNA, which is present in the cell nucleus and inherited from both parents, mtDNA is inherited solely from the mother.

MtDNA is a circular molecule that contains 37 genes, including 13 genes that encode for proteins involved in oxidative phosphorylation, a process that generates energy in the form of ATP. The remaining genes encode for rRNAs and tRNAs, which are necessary for protein synthesis within the mitochondria.

Mutations in mtDNA can lead to a variety of genetic disorders, including mitochondrial diseases, which can affect any organ system in the body. These mutations can also be used in forensic science to identify individuals and establish biological relationships.

Exonucleases are a type of enzyme that cleaves nucleotides from the ends of a DNA or RNA molecule. They differ from endonucleases, which cut internal bonds within the nucleic acid chain. Exonucleases can be further classified based on whether they remove nucleotides from the 5' or 3' end of the molecule.

5' exonucleases remove nucleotides from the 5' end of the molecule, starting at the terminal phosphate group and working their way towards the interior of the molecule. This process releases nucleotide monophosphates (NMPs) as products.

3' exonucleases, on the other hand, remove nucleotides from the 3' end of the molecule, starting at the terminal hydroxyl group and working their way towards the interior of the molecule. This process releases nucleoside diphosphates (NDPs) as products.

Exonucleases play important roles in various biological processes, including DNA replication, repair, and degradation, as well as RNA processing and turnover. They are also used in molecular biology research for a variety of applications, such as DNA sequencing, cloning, and genome engineering.

Viologens, also known as methylviologen dyes or paraquat salts, are a group of chemical compounds that have the general structure of bis(dimethylpyridinium). They are widely used in research as electron acceptors and in commercial applications such as herbicides. Viologens can undergo redox reactions, which make them useful for studies involving electron transfer. However, they can also be toxic to living organisms, including humans, due to their ability to generate reactive oxygen species that damage cells.

A lymphocyte count is a laboratory test that measures the number of white blood cells called lymphocytes in a sample of blood. Lymphocytes are a vital part of the immune system and help fight off infections and diseases. A normal lymphocyte count ranges from 1,000 to 4,800 cells per microliter (µL) of blood for adults.

An abnormal lymphocyte count can indicate an infection, immune disorder, or blood cancer. A low lymphocyte count is called lymphopenia, while a high lymphocyte count is called lymphocytosis. The cause of an abnormal lymphocyte count should be investigated through further testing and clinical evaluation.

Genetic models are theoretical frameworks used in genetics to describe and explain the inheritance patterns and genetic architecture of traits, diseases, or phenomena. These models are based on mathematical equations and statistical methods that incorporate information about gene frequencies, modes of inheritance, and the effects of environmental factors. They can be used to predict the probability of certain genetic outcomes, to understand the genetic basis of complex traits, and to inform medical management and treatment decisions.

There are several types of genetic models, including:

1. Mendelian models: These models describe the inheritance patterns of simple genetic traits that follow Mendel's laws of segregation and independent assortment. Examples include autosomal dominant, autosomal recessive, and X-linked inheritance.
2. Complex trait models: These models describe the inheritance patterns of complex traits that are influenced by multiple genes and environmental factors. Examples include heart disease, diabetes, and cancer.
3. Population genetics models: These models describe the distribution and frequency of genetic variants within populations over time. They can be used to study evolutionary processes, such as natural selection and genetic drift.
4. Quantitative genetics models: These models describe the relationship between genetic variation and phenotypic variation in continuous traits, such as height or IQ. They can be used to estimate heritability and to identify quantitative trait loci (QTLs) that contribute to trait variation.
5. Statistical genetics models: These models use statistical methods to analyze genetic data and infer the presence of genetic associations or linkage. They can be used to identify genetic risk factors for diseases or traits.

Overall, genetic models are essential tools in genetics research and medical genetics, as they allow researchers to make predictions about genetic outcomes, test hypotheses about the genetic basis of traits and diseases, and develop strategies for prevention, diagnosis, and treatment.

T-lymphocytes, also known as T-cells, are a type of white blood cell that plays a key role in the adaptive immune system's response to infection. They are produced in the bone marrow and mature in the thymus gland. There are several different types of T-cells, including CD4+ helper T-cells, CD8+ cytotoxic T-cells, and regulatory T-cells (Tregs).

CD4+ helper T-cells assist in activating other immune cells, such as B-lymphocytes and macrophages. They also produce cytokines, which are signaling molecules that help coordinate the immune response. CD8+ cytotoxic T-cells directly kill infected cells by releasing toxic substances. Regulatory T-cells help maintain immune tolerance and prevent autoimmune diseases by suppressing the activity of other immune cells.

T-lymphocytes are important in the immune response to viral infections, cancer, and other diseases. Dysfunction or depletion of T-cells can lead to immunodeficiency and increased susceptibility to infections. On the other hand, an overactive T-cell response can contribute to autoimmune diseases and chronic inflammation.

Reproducibility of results in a medical context refers to the ability to obtain consistent and comparable findings when a particular experiment or study is repeated, either by the same researcher or by different researchers, following the same experimental protocol. It is an essential principle in scientific research that helps to ensure the validity and reliability of research findings.

In medical research, reproducibility of results is crucial for establishing the effectiveness and safety of new treatments, interventions, or diagnostic tools. It involves conducting well-designed studies with adequate sample sizes, appropriate statistical analyses, and transparent reporting of methods and findings to allow other researchers to replicate the study and confirm or refute the results.

The lack of reproducibility in medical research has become a significant concern in recent years, as several high-profile studies have failed to produce consistent findings when replicated by other researchers. This has led to increased scrutiny of research practices and a call for greater transparency, rigor, and standardization in the conduct and reporting of medical research.

Thymectomy is a surgical procedure that involves the removal of the thymus gland. The thymus gland is a part of the immune system located in the upper chest, behind the sternum (breastbone), and above the heart. It is responsible for producing white blood cells called T-lymphocytes, which help fight infections.

Thymectomy is often performed as a treatment option for patients with certain medical conditions, such as:

* Myasthenia gravis: an autoimmune disorder that causes muscle weakness and fatigue. In some cases, the thymus gland may contain abnormal cells that contribute to the development of myasthenia gravis. Removing the thymus gland can help improve symptoms in some patients with this condition.
* Thymomas: tumors that develop in the thymus gland. While most thymomas are benign (non-cancerous), some can be malignant (cancerous) and may require surgical removal.
* Myasthenic syndrome: a group of disorders characterized by muscle weakness and fatigue, similar to myasthenia gravis. In some cases, the thymus gland may be abnormal and contribute to the development of these conditions. Removing the thymus gland can help improve symptoms in some patients.

Thymectomy can be performed using various surgical approaches, including open surgery (through a large incision in the chest), video-assisted thoracoscopic surgery (VATS, using small incisions and a camera to guide the procedure), or robotic-assisted surgery (using a robot to perform the procedure through small incisions). The choice of surgical approach depends on several factors, including the size and location of the thymus gland, the patient's overall health, and the surgeon's expertise.

The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a ... Circle of Willis Circle of Willis Cerebral circulation Leptomeningeal collateral circulation Fenrich, Matija; Habjanovic, Karlo ... Thomas Willis' Famous Eponym: The Circle of Willis". Journal of the History of the Neurosciences. 14 (1): 16-21. doi:10.1080/ ... It is named after Thomas Willis (1621-1675), an English physician. The circle of Willis is a part of the cerebral circulation ...
... won the 2014 National Book Critics Circle Award for criticism. "Willis, Ellen. Papers of Ellen Willis, 1941-2011". Retrieved ... "National Book Critics Circle: awards". National Book Critics Circle. Archived from the original on October 18, 2015. Retrieved ... "National Book Critics Circle: awards". National Book Critics Circle. Archived from the original on October 18, 2015. Retrieved ... Collected papers of her mother, Ellen Willis, at Harvard. Aronowitz, Nona Willis (August 9, 2022). "Why I Stayed in a Marriage ...
The Essential Ellen Willis, edited by Nona Willis Aronowitz, won the 2014 National Book Critics Circle Award (Criticism). ... Ellen Willis Tumblr Page - large collection of Willis's writings. "Ellen Willis, 64, Journalist and Feminist, Dies" by Margalit ... Willis, Ellen (2014). Willis-Aronowitz, Nona (ed.). The Essential Ellen Willis. University of Minnesota. ISBN 978-0-8166-8121-1 ... A 2014 collection of her essays, The Essential Ellen Willis, received the National Book Critics Circle Award for Criticism. ...
"Sojourner Truth Leadership Circle - Auburn Seminary". Archived from the original on 2021-01-20. Retrieved 2020-12-31. " ... In 2020, Willis won the GLAAD Media Award for Outstanding Magazine Article. Willis was born and raised in Augusta, Georgia. She ... Willis graduated in 2013 with a bachelor's degree in journalism. Following graduation from UGA, Willis moved to Atlanta and ... Willis, Raquel. "Bio". Raquel Willis. Archived from the original on September 20, 2017. Retrieved September 19, 2017. "The ...
He died in Angola in 1956; interment was in Circle Hill Cemetery. https://www.capitolandwashington.com/politicians/pol/184/ ... "Raymond E. Willis (id: W000563)". Biographical Directory of the United States Congress. Raymond E Willis papers, Rare Books and ... Raymond Eugene Willis (August 11, 1875 - March 21, 1956) was a United States senator from Indiana. Born in Waterloo, Indiana, ... From 1918 to 1922, Willis was a member of the Indiana House of Representatives. He was an unsuccessful candidate for election ...
"Rick Dudley comes full circle in return to North Carolina". The Athletic. Retrieved July 9, 2018. Willis, Jonathan. "Leafs' ...
doi:10.1161/CIR.0000000000000534. PMID 29061565. S2CID 22236795. "Physical exercise and dementia , Alzheimer's Society". www. ... Willis, Monte; Yancy, Clyde W. (2017-11-21). "Cardiovascular Health in African Americans: A Scientific Statement From the ...
Willis, Mike. "Bespoke People: Man of Change" Archived 6 March 2012 at the Wayback Machine, Bespoke, Beirut, July 2008. Bridge ... "Circle Capital Executive Team". circlecapital.co.za. Archived from the original on 14 April 2010. Retrieved 24 May 2010. " ... Biko worked for the World Bank in Washington, D.C., in 1998[citation needed]. Biko and Ramphele co-founded Circle Capital, an ... Biko was the CEO of Circle Capital. In 2008, Bespoke Magazine called him "the driving force behind a multi-million rand black ...
Barr v. Lafon' (6th Cir. August 20, 2008).Text "Stoner, A. Derrick. "The Daily Times: What I Think."". Archived from the ... "H.K. Edgerton: In This Case "Uncle Tom" Is Perfectly Accurate". Oliver Willis. Archived from the original on 2012-04-15. ...
A-1 "Clinic and U. Circle Inc. Accused of Land Squeeze". The Plain Dealer. July 13, 1977. "Willis Alleges Land Squeeze In Area ... Willis and his wife, Alberta Frazier Willis, both natives of Montgomery. The Willis children attended St. Jude Educational ... Willis opened and operated numerous businesses on the Euclid Avenue strip. He established University Circle Properties ... Willis fought the city with lawsuits, as reported in the local press, "Willis, who has made a battleground of the courts in his ...
Kells, Lyman M.; Kern, Willis F.; Bland, James R. (1940). Plane And Spherical Trigonometry. McGraw Hill Book Company, Inc. pp. ... great circles'. The determination of the great-circle distance is part of the more general problem of great-circle navigation, ... The great circle distance is proportional to the central angle. The great circle chord length, C h {\displaystyle C_{h}\,\!} , ... The great-circle distance, orthodromic distance, or spherical distance is the distance along a great circle. It is the shortest ...
ISBN 0-7935-9365-4. Willis 2000, p. 52. "1994 Academy Awards Nominees and Winners by Category". Box Office Mojo. Retrieved 3 ... "Elton John - Circle of Life" (in German). Ö3 Austria Top 40. "Elton John - Circle of Life" (in Dutch). Ultratop 50. "Top RPM ... "Elton John - Circle of Life". Singles Top 100. "Elton John - Circle of Life". Swiss Singles Chart. "Official Singles Chart Top ... "Elton John: Circle of Life". IMDb. Retrieved 9 September 2021. "Elton John - Circle of Life (From "The Lion King"/Official ...
Dear America: A Line in the Sand at IMDb Monush & Willis 2005, p. 190. "Davy Crockett musical play". AllMusic. Retrieved ... ISBN 978-0-8108-8133-4. Michno, Gregory; Michno, Gregory F.; Michno, Susan (2008). Circle the Wagons!: Attacks on Wagon Trains ... ISBN 978-0-7864-3997-3. Monush, Barry; Willis, John (2005). Screen World: 2004 Film Annual. New York: Applause Theatre & Cinema ...
"Music Circle Notes". Fort Worth Star-Telegram. 1916-03-19. "Hogan-Losh Wedding Is Big Surprise". Fort Worth Star-Telegram. 1923 ... Willis, Libby (2014). Fort Worth's Oakhurst Neighborhood. Arcadia Publishing. ISBN 978-1-4671-3116-2. "Losh Says Permanent Home ... samuel s. losh 1884-. "1943 Sam Losh, Active in Music Circles for 30 Years, Dies". Fort Worth Star-Telegram. 1943-06-04. " ...
The Coles' circle of friends contained many notable persons of the day. Authors, playwrights, politicians, royalty, scientists ... Willis Vernon Cole was born in Detroit, Michigan, on March 3, 1882, to Willis Herbert Cole and Mary Elizabeth Stinchfield. He ... Willis Vernon Cole died on March 7, 1939, in Luynes, France, shortly before the German invasion, and is buried there. His death ... Willis Vernon Cole (1882 - 1939) was an American poet and author. He produced five volumes of poetry, and four historical ...
Circle nomination for Newcomer of the Year (2000). Willis, Margaret E (2001). Dancer profile: Molly Smolen. pp. 684-685. OCLC ...
His most notable discovery was the "Circle of Willis", a circle of arteries on the base of the brain. Willis's anatomy of the ... who had met Willis in London. Willis was the first to identify achalasia cardia in 1672. Willis's work gained currency in ... Thomas Willis. Whonamedit. Retrieved on 17 July 2012. Willis T. An Essay of the Pathology of the Brain and Nervous Stock: In ... Browne Willis, the antiquary, was son of Thomas Willis (1658-1699), the eldest son of Thomas and Mary. Between 1724 and 1730, ...
Willis, John (2000-02-01). Screen World 1993: Comprehensive Pictorial and Statistical Record of the 1992 Movie Season. Hal ... "Arthur Mendoza's Actor Circle Theatre , Best Acting School in Los Angeles". www.actorcircletheatre.com. Retrieved 2022-04-26. " ... He has directed productions at the Actors Circle Theatre, including The Glass Menagerie. Mendoza coaches at the Santa Monica ... Mendoza is the founder, artistic director and principal acting instructor at the Actors Circle Theatre in Los Angeles, ...
Willis, Kiersten (August 21, 2018). "Trina Braxton Replaces Kiana Dancie on 'Sister Circle': 'I Did Not Forsee This'". "Another ... "About 'Sister Circle'". September 7, 2017. Moseley, Eunice (September 15, 2018). "The Pulse of Entertainment: 'Sister Circle' ... Since September 2018, Braxton is a co-host of "Sister Circle" talk show for the TV One and TEGNA networks from 12:00 p.m. - 1 p ... "Sister Circle" talk show for the TV One and TEGNA networks from 12:00 p.m. - 1 p.m., along with Quad Webb-Lunceford, Syleena ...
Avento, Joe (15 January 1997). "Willis enters winners circle again". Johnson City Press. Johnson City, Tennessee. p. 25. ...
Vrselja, Zvonimir; Brkic, Hrvoje; Mrdenovic, Stefan; Radic, Radivoje; Curic, Goran (2014). "Function of Circle of Willis". ... Goran Function of circle of Willis. // Journal of cerebral blood flow and metabolism, 34 (2014) Hrvoje, Brkić; Daniela, ...
16 (1): 1. Willis, Linda (February 2, 1987). "Working in Circles: Loy Uses Mandalas To Convey Artistic Message". Franklin News- ... a Sanskrit word that means circle. The art columnist for The Roanoke Times dubbed Loy's works a mix of "magic circles, ...
Willis, Jackie (October 16, 2017). "Pussycat Dolls Founder Robin Antin Slams Kaya Jones' Claims that the Group Was a ' ... Your National Electronic Talking Circle. Retrieved January 8, 2018. Plott, Elaina (October 19, 2017). "How a Former Pussycat ...
In 2019, Willis replaced Alice Levine and Maya Jama as host of The Circle. In 2010, it was announced that Willis would replace ... Willis is also a guest presenter on The One Show from time to time. On 5 August 2012, Willis began co-presenting Sunday Morning ... In 2013, Willis co-presented the ITV game show Prize Island with Alexander Armstrong. In 2015, Willis was a team captain on the ... Willis has expressed personal pride on this moment in her career. On 30 March 2014, Willis presented the Mum of the Year Awards ...
His membership of The Magic Circle was a source of inspiration for these books. He also wrote 40 radio and television plays, as ... Willis Edward Hall (6 April 1929 - 7 March 2005) was an English playwright and radio, television and film writer who drew on ... Willis Hall also wrote 'The Royal Astrologer', a collection of separate stories for children relating the adventures of Father ... Willis formed an extremely prolific partnership with his life-long friend Keith Waterhouse producing over 250 works. He wrote ...
Vanessa Urruela Willis (May 20, 2002). "WFU comes full circle as Divinity School celebrates first graduates". Wake Forest ...
See Circle of latitude#Movement of the Tropical and Polar circles. Willis states that "this means there was a living oral ... Willis 2009, pp. 15-27, 248. Willis 2009, pp. 1-3, 54, 248. JF Fleet (1888), Inscriptions of the Early Gupta Kings and Their ... Willis 2009, pp. 29, 251-252. Willis 2009, pp. 12-13. Meera Dass 2001, p. 12. J. C. Harle, Gupta Sculpture: Indian Sculpture of ... Willis 2009, pp. 4-5, 39-41. Willis 2009, pp. 4-5, 39-41, 200. Meera Dass 2001, pp. 280-282. Meera Dass 2001, pp. 88. Meera ...
Hammerstein, p. 175 Block (ed.), p. 95 Past Awards (1945-1946), New York Drama Critics' Circle. dramacritics.org. Retrieved on ... January 25, 2012 Willis, John. "Previous Theatre World Award Recipients". Hal Leonard Corporation, 2009, p. 364 ISBN 978-1-4234 ...
William Innes Homer, Robert Henri and His Circle (Ithaca, New York and London: 1969, p. 112. Edward Redfield, cited in ... Wikimedia Commons has media related to Edward Willis Redfield. Huge gallery of paintings Edward Willis Redfield Biography: ... "Edward Willis Redfield, Road to the River," in Kevin Sharp. Masters of Light, Selections of American Impressionism from the ... Tom Folk, "Edward Willis Redfield, Road to the River," in Kevin Sharp, Masters of Light, Selections of American Impressionism ...
Screen World 2001 By John Willis, Barry Monush. Hal Leonard Corporation. p.45 "In Memory of Christopher Pettiet". The Actor's ... Circle. Archived from the original on June 10, 2015. Retrieved March 26, 2013. "12th Annual Youth In Film Awards". ...
The circle of Willis (also called Willis circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a ... Circle of Willis Circle of Willis Cerebral circulation Leptomeningeal collateral circulation Fenrich, Matija; Habjanovic, Karlo ... Thomas Willis Famous Eponym: The Circle of Willis". Journal of the History of the Neurosciences. 14 (1): 16-21. doi:10.1080/ ... It is named after Thomas Willis (1621-1675), an English physician. The circle of Willis is a part of the cerebral circulation ...
At the Circle of Willis, the internal carotid arteries branch into smaller arteries that supply ... The Circle of Willis is the joining area of several arteries at the bottom (inferior) side of the brain. ... The Circle of Willis is the joining area of several arteries at the bottom (inferior) side of the brain. At the Circle of ... Willis, the internal carotid arteries branch into smaller arteries that supply oxygenated blood to over 80% of the cerebrum. ...
Online download statistics by month: March 2009 to August ...
Assessment of the Collateral Function of the Circle of Willis. Arjan W.J. Hoksbergen, Charles B.L. Majoie, Frans-Jan H. ... Assessment of the Collateral Function of the Circle of Willis. Arjan W.J. Hoksbergen, Charles B.L. Majoie, Frans-Jan H. ... The circle of Willis, located at the base of the brain, provides the main route for collateral blood flow in severe occlusive ... The circle of Willis-The incidence of developmental abnormalities in normal and infarcted brains. Brain 1967;90:747-758. ...
Impact of anatomical variations of the circle of Willis on the incidence of aneurysms and their recurrence rate following ...
Circle Of Willis Circle of Willis is a rock-fueled, pop-centric, jazz-tinged, blues-infused agent of auditory ecstasy. The band ... Circle of Willis is a rock-fueled, pop-centric, jazz-tinged, blues-infused agent of auditory ecstasy. The band performs their ...
Save my name, email, and website in this browser for the next time I comment ...
Negative Circle. *Project Detail. Category:. Multi-media & Sculpture. Media:. Stone & Ceramic. Project Number:. 105. Date:. No ...
Circle Of Willis transparent PNG image, clipart picture with no background - circles ... CategoriesCirclesCircle Of Willis. Download Circle Of Willis transparent PNG. You can download in a tap this free Circle Of ... Willis transparent PNG image. As you can see, theres no background. Use it for your creative projects or simply as a sticker ...
The circle of Willis begins to form when the right and left internal carotid artery (ICA) enters the cranial cavity and each ... The circle of Willis encircles the stalk of the pituitary gland and provides important communications between the blood supply ... Although a complete circle of Willis is present in some individuals, it is rarely seen radiographically in its entirety; ... Schematic of the circle of Willis and cerebral vasculature in relation to local anatomy. Courtesy of Wikimedia Commons. ...
Edit the `_data/repositories.yml` and change the `github_users` and `github_repos` lists to include your own GitHub profile and repositories.
... and the location with the most branch points is the circle of Willis. The circle of Willis is in close proximity to the ventral ... The circle of Willis is an anastomotic circle of the important arteries that supply the brain from the heart: the two vertebral ... The posterior segment of the circle of Willis consists of the basilar apex and the proximal portions of the posterior cerebral ... The anterior portion of the circle of Willis consists of the internal carotid arteries, the posterior communicating artery, the ...
ALL WITHIN THE CIRCLE OF WILLIS: Prologue. The Circle of Willis is an antiquated name for the arterial circle at the base of ... the Circle of Willis serves as a gateway between the mind, body and the environment. All within the Circle of Willis refers to ... all within the circle of willis, empires are built not with tools but by them. ...
The circle of Willis (circulus arteriosus cerebri) is an anastomotic system of arteries that sits at the base of the brain. The ... encoded search term (Circle of Willis Anatomy) and Circle of Willis Anatomy What to Read Next on Medscape ... The "circle" was named after Thomas Willis by his student Richard Lower. Willis was the author of Cerebri Anatome, a book that ... Circle of Willis Anatomy. Updated: Jun 03, 2013 * Author: R Shane Tubbs, MS, PA-C, PhD; Chief Editor: Brian H Kopell, MD more ...
The circle of Willis (circulus arteriosus cerebri) is an anastomotic system of arteries that sits at the base of the brain. The ... encoded search term (Circle of Willis Anatomy) and Circle of Willis Anatomy What to Read Next on Medscape ... The "circle" was named after Thomas Willis by his student Richard Lower. Willis was the author of Cerebri Anatome, a book that ... Circle of Willis Anatomy. Updated: Jun 03, 2013 * Author: R Shane Tubbs, MS, PA-C, PhD; Chief Editor: Brian H Kopell, MD more ...
Here there is a bigger truth, a narrative which places your life in the context of the sacred circle of life. It is a place to ... When we honor the rhythms of the Earths seasons, the spiral and circle of life, as our ancestors have for thousands of years, ...
Circle of Willis. Part of Book Engravings of the arteries : illustrating the second volume of the Anatomy of the human body, ... Brain, circle of Willis, shown in isolation, inferior view.. General Note(s) Plate signed by the artist: Charles Bell; and by ...
Learn more from Crawford/Willis Group. The formal dining room has coffered ceilings and wainscoting. ... Information is deemed reliable but is not guaranteed accurate by the MLS or Crawford/Willis Group , eXp Realty. Data last ... Information is deemed reliable but is not guaranteed accurate by the MLS or Crawford/Willis Group , eXp Realty. Data last ... Information is deemed reliable but is not guaranteed accurate by the MLS or Crawford/Willis Group , eXp Realty. Data last ...
Actor Bruce Willis has frontotemporal dementia, his own circle of relatives has announced. ... Bruce Willis has dementia, his own circle of relatives announces.. ByMr Farhaan February 17, 2023. February 17, 2023. Write a ... But his own circle of relatives stated closing 12 months that Willis might surrender acting, as his aphasia became affecting ... The declaration became signed via way of means of contributors of Williss own circle of relatives which includes his spouse ...
See Thomas v. Arn, 474 U.S. 140 7 (1985); United States v. Walters, 638 F.2d 947 (6th Cir. 1981). IT IS SO ORDERED. Date: May ... Willis v. Big Lots, Inc. et al Filing 93 Willis v. Big Lots, Inc. et al ... LEXIS 16936 (6th Cir. 2016)). Thus, the Court rejected Defendants argument that they could rebut Basics presumption of price ... Litig., 838 F.3d 223, 258 (2nd Cir. 2016) ("[I]t is hardly illogical or inconsistent with precedent to find a statement may ...
Carotid and Circle of Willis 2013. Brain, and Head and Neck Neuro CTA - Carotid and Circle of Willis 2013. ...
Find Willis Ranch, Chandler, AZ apartments for rent that youll love on Redfin. Browse verified local listings, photos, video, ... 1405 E Chicago Cir, Chandler, AZ 85225. House. Request a tour. (844) 305-2877 ... More to explore in Willis Ranch. Property Types. *Houses for rent in Willis Ranch ... Willis Ranch House for Rent. Front Lake Gorgeous property PRIME LOCATION IN THE SPRINGS on a cul-de-sac street in a Private ...
Together with the Legacy Circle, you sustain the mission of APS.. Join the APS Loyal Donors Circle. Contact APS Development to ... Current Loyal Donor Circle Members. You are an invaluable part of APS and we are grateful for your dedication to advancing our ... The Loyal Donors Circle honors APSs annual donors. Through continuous giving, you expand and create opportunities for the ...
Sharon Romeo-Willis. GCAC Directors Circle Member. Sharon Romeo-Willis is currently an Instructional Coach for CSI and ATSI ... Sharon Romeo-Willis is the founder of "Lift the Gifted", which creates curriculum for all students, using GATE curriculum to ...
See United States v. Dougherty, 154 U.S.App.D.C. 76, 473 F.2d 1113 (1972); United States v. Moylan, 417 F.2d 1002 (4 Cir. 1969 ... Justia › US Law › Case Law › Iowa Case Law › Iowa Supreme Court Decisions › 1974 › State v. Willis State v. Willis. Annotate ... Defendant Garole Lee Willis appeals judgment entered on a jury verdict convicting her of soliciting under Code § 724.2. She ... 2d 91 (appeal from the trial of "the Cantonsville eight"); United States v. Dellinger, 472 F.2d 340 (7 Cir. 1972), cert. denied ...
... and artery-specific dynamic angiography of a large number of arterial branches above the circle of Willis within a clinically ... Visualizing artery-specific blood flow patterns above the circle of Willis with vessel-encoded arterial spin labeling. ... Visualizing artery-specific blood flow patterns above the circle of Willis with vessel-encoded arterial spin labeling. ... and artery-specific dynamic angiography of a large number of arterial branches above the circle of Willis within a clinically ...
Known as Sun Drop to many friends and co workers over the years, Willis was a member of the Hardin Chapel Church of … ... Phil Willis, 70, of Lewisburg, passed away Friday, July 15, 2022, at his home. ... Stephen Wells of Lewisburg and Cooper Willis of Murfreesboro; and a granddaughter Sarah Katherine Willis of Murfreesboro. He is ... Known as Sun Drop to many friends and co workers over the years, Willis was a member of the Hardin Chapel Church of Christ, the ...
Excludes: Ruptured aneurysm (congenital) circle of Willis (I6060). *I6060 Ruptured aneurysm (congenital) circle of Willis ...
Willis arterial polygon is described as the arterial circle of the base of the skull, functioning as a vascular compensation ... Willis arterial polygon is described as the arterial circle of the base of the skull, functioning as a vascular compensation ... Home 2019 INJECTION OF PLASTIC MATERIAL INTO THE VESSELS OF WILLIS CIRCLE (BASILAR TRUNK... ... INJECTION OF PLASTIC MATERIAL INTO THE VESSELS OF WILLIS CIRCLE (BASILAR TRUNK AND CAROTIDE ARTERIES). ...
Circle Of Champions Award-2 years. Honor Ring-7 years. Inner Circle Elite Award-1 years ... Brady Willis is insurance licensed in the state(s) of Texas. If you do not reside in the state(s) of Texas, please go to the ... Local Allstate Agent: Meet Brady Willis. Video PlatformVideo ManagementVideo SolutionsVideo Player. ...
  • Schematic of the circle of Willis and cerebral vasculature in relation to local anatomy. (naqlafshk.com)
  • At the Circle of Willis, the internal carotid arteries branch into smaller arteries that supply oxygenated blood to over 80% of the cerebrum. (medlineplus.gov)
  • The Circle of Willis is an antiquated name for the arterial circle at the base of the brain that receives and distributes all the blood that is pumped up the two internal carotid arteries traveling into the brain. (matbrown.org)
  • Some branches join to form a circle of arteries (circle of Willis) that connect the vertebral and internal carotid arteries. (msdmanuals.com)
  • The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including humans. (wikipedia.org)
  • The anterior cerebral artery forms the anterolateral portion of the circle of Willis, while the middle cerebral artery does not contribute to the circle. (wikipedia.org)
  • The arrangement of the brain's arteries into the circle of Willis is believed to create redundancy (analogous to engineered redundancy) for collateral circulation in the cerebral circulation. (wikipedia.org)
  • If one part of the circle becomes blocked or narrowed (stenosed) or one of the arteries supplying the circle is blocked or narrowed, blood flow from the other blood vessels can often preserve the cerebral perfusion well enough to avoid the symptoms of ischemia. (wikipedia.org)
  • The adaptive flow that the circle of Willis introduces can also lead to reduced cerebral perfusion. (wikipedia.org)
  • Fetal ultrasound image at the level of circle of Willis, showing PCA, MCA and ACA Cerebral angiogram showing an anterior/posterior projection of the vertebrobasilar and posterior cerebral circulation, the posterior aspect of the circle of Willis, and one of its feeding vessels An anterior view of major cerebral and cerebellar arteries. (wikipedia.org)
  • Knowledge of the collateral ability of the circle of Willis is important for neurosurgeons, vascular surgeons, and interventional radiologists when a procedure in the intracranial or extracranial cerebral arteries is to be attempted. (ajnr.org)
  • The circle of Willis begins to form when the right and left internal carotid artery (ICA) enters the cranial cavity and each one divides into two main branches: the anterior cerebral artery (ACA) and middle cerebral artery (MCA). (naqlafshk.com)
  • The circle of Willis is formed when the internal carotid artery (ICA) enters the cranial cavity bilaterally and divides into the anterior cerebral artery (ACA) and middle cerebral artery (MCA). (medscape.com)
  • Nowadays, even if this is the accepted theory, the clinical evolution of some cases invalidates or at least calls into question the contribution of the Willis arterial circle to the filling of cerebral vascularity. (ijmd.ro)
  • Willis was the author of Cerebri Anatome, a book that described and depicted this vascular ring. (medscape.com)
  • Although such a vascular ring had been described earlier, the name Willis has been eponymously propagated. (medscape.com)
  • PURPOSE: To establish the feasibility of using vessel-encoded pseudocontinuous arterial spin labeling (VEPCASL) for noninvasive vascular territory imaging (VTI) and artery-specific dynamic angiography of a large number of arterial branches above the circle of Willis within a clinically feasible scan time. (ox.ac.uk)
  • Willis arterial polygon is described as the arterial circle of the base of the skull, functioning as a vascular compensation system in case of occlusion of one of the branches. (ijmd.ro)
  • Also, in some cases, hypoplastic branches were identified, without distal infusion, the plastic material not being evidenced in the efferent vessels.The purpose of this study: plastic injection into the vessels of the arterial polygon, was to investigate the vascular competence of the branches of the Willis arterial circle. (ijmd.ro)
  • Considerable anatomic variation exists in the circle of Willis, with classic anatomy seen only in about one-third of people. (wikipedia.org)
  • MR angiography is an attractive, noninvasive technique for assessing the anatomy of the circle of Willis ( 3 ). (ajnr.org)
  • The central branches supply the interior of the circle of Willis, more specifically, the Interpeduncular fossa. (wikipedia.org)
  • The cortical branches are named for the area they supply and do not directly affect the circle of Willis. (wikipedia.org)
  • Magnetic resonance arteriography illustrating the circle of Willis and its branches. (naqlafshk.com)
  • However, considering that the circle of Willis is present in many non-human species (reptiles, birds and mammals), and that arterial narrowing is mostly associated with old age and the human lifestyle, more generally applicable explanations of its functions have been suggested, such as dampening of pulse pressure waves within the brain and involvement in forebrain sensing of water loss. (wikipedia.org)
  • The Circle of Willis is the joining area of several arteries at the bottom (inferior) side of the brain. (medlineplus.gov)
  • The circle of Willis, located at the base of the brain, provides the main route for collateral blood flow in severe occlusive disease of the internal carotid artery (ICA). (ajnr.org)
  • This crucial artery supplies the brain and all its functions with fuel, elegantly wrapped around the pituitary gland, the Circle of Willis serves as a gateway between the mind, body and the environment. (matbrown.org)
  • The circle of Willis (circulus arteriosus cerebri) is an anastomotic system of arteries that sits at the base of the brain. (medscape.com)
  • Schematic representation of the circle of Willis, arteries of the brain, and brainstem. (medscape.com)
  • Aneurysms associated with subarachnoid hemorrhages tend to occur in a circle of arteries that supply blood to the brain. (medicalnewstoday.com)
  • At the base of the brain, the carotid and basilar systems join to form a circle of large, communicating arteries known as the circle of Willis. (medscape.com)
  • Most common are the saccular (berry) aneurysms located at branch points in CIRCLE OF WILLIS at the base of the brain. (bvsalud.org)
  • Visible collaterals of the circle of Willis on MR angiograms are able to supply collateral flow in the presence of carotid artery obstruction. (ajnr.org)
  • The circle of Willis encircles the stalk of the pituitary gland and provides important communications between the blood supply of the forebrain and hindbrain (ie, between the internal carotid and vertebro-basilar systems following obliteration of primitive embryonic connections). (naqlafshk.com)
  • The PCAs complete the circle of Willis by joining the internal carotid system anteriorly via the posterior communicating (PCOM) arteries. (medscape.com)
  • The method used for filling was injection of plastic material into the vessels that contribute to the formation of the Willis polygon, namely the basilar trunk and the carotid arteries. (ijmd.ro)
  • However, the presence of an aberrant right subclavian artery and enough blood flow through the circle of Willis allowed perfusion of the coronary arteries through retrograde carotid and aortic blood flow . (bvsalud.org)
  • It is named after Thomas Willis (1621-1675), an English physician. (wikipedia.org)
  • The "circle" was named after Thomas Willis by his student Richard Lower. (medscape.com)
  • Through the technique of postmortem arterial mold, we have highlighted the degree of perfusion and filling of the efferent arteries in the Willis arterial circle. (ijmd.ro)
  • Interrupted aortic arch and aortic atresia with circle of Willis-dependent coronary perfusion. (bvsalud.org)
  • Most aneurysms occur at bifurcations of the intracranial arteries, and the location with the most branch points is the circle of Willis. (medscape.com)
  • Intracranial aneurysms are balloon-like dilations of arteries often occurring at branching points in the circle of Willis. (ajnr.org)
  • Unfortunately, hypoplasia of vessel segments frequently hampers the collateral function of the circle of Willis ( Fig 1 ). (ajnr.org)
  • Examples and prevalence of circle of Willis anomalies that hamper collateral function. (ajnr.org)
  • The PCAs complete the circle of Willis by joining the anterior circulation formed by the ICAs via the posterior communicating (PCOM) arteries. (naqlafshk.com)
  • These connections form the anterior half (anterior circulation) of the circle of Willis. (medscape.com)
  • US journalist Maria Shriver, a outstanding campaigner for mind sickness affected person care and research, tweeted: "My coronary heart is going out to Bruce Willis and his own circle of relatives, & additionally my gratitude for shining a miles wished mild in this sickness. (bolly24.com)
  • He was preceded in death by his parents, Sara and Berdell Willis of Lewisburg, and by his wife Janice in 2017. (marshalltribune.com)
  • In a tweet, the official Earth, Wind & Fire Twitter page, shared: "Allee Willis was a one-of-a-kind creative genius. (grammy.com)
  • Born in Detroit, Willis grew up in the Motown era and developed a passion for the music. (grammy.com)
  • Schematic drawing of the circle of Willis as found at the base of the skull. (medscape.com)
  • Los aneurismas saculares son la variante más común y tienden a formarse en los puntos de ramificación arterial en el POLÍGONO DE WILLIS en la base del encéfalo. (bvsalud.org)
  • When we honor the rhythms of the Earth's seasons, the spiral and circle of life, as our ancestors have for thousands of years, something happens to us internally. (redearthhealing.org)
  • Years ago, we named this blog "Willis Wired" simply to indicate our online presence. (williswired.com)
  • Willis' partner of over 25 years, Prudence Fenton, confirmed the death on Instagram . (grammy.com)
  • You can download in a tap this free Circle Of Willis transparent PNG image. (stickpng.com)
  • Paying homage to one of Willis' biggest hits, Fenton wrote "Rest In Boogie Wonderland" on her Instagram post with an image of Willis in front of a historic Motown site. (grammy.com)
  • Emma Willis causes a stir with photo of rarely seen daughter Trixie - and she looks so grown up! (hellomagazine.com)
  • Beyond music, Willis, who was a Los Angeles resident, directed music videos and was known for her colorful style and taste. (grammy.com)
  • Visualizing artery-specific blood flow patterns above the circle of Willis with vessel-encoded arterial spin labeling. (ox.ac.uk)
  • Contact APS Development to express your interest in becoming part of the Loyal Donors Circle. (aps.org)
  • Subclavian steal syndrome has potential to affect flow in the circle of Willis. (wikipedia.org)
  • These arteries include the circle of Willis and connections between the arteries that branch off from the circle. (msdmanuals.com)
  • A complete circle of Willis is present in most individuals, although a well-developed communication between each of its parts is identified in less than half of the population. (medscape.com)
  • The 67-12 months-antique became recognized with aphasia - which reasons problems with speech - in spring closing 12 months, however this has stepped forward and he has been given a extra particular prognosis, the own circle of relatives stated. (bolly24.com)
  • But his own circle of relatives stated closing 12 months that Willis might surrender acting, as his aphasia became affecting his cognitive abilities. (bolly24.com)
  • Emma, 43, captioned the photo: 'Turns out the weather changes very quickly…' and fans were quick to let The Circle host know just how much they related. (hellomagazine.com)
  • Of her songwriting style, Willis told the Library of Congress , her music was about resilience. (grammy.com)
  • Damage to those areas influences language (the sort of Mr Willis' aphasia) in addition to behaviour and the capacity to plan. (bolly24.com)
  • Aaron Paul, who starred in America's Breaking Bad TV crime drama, stated Willis became "the sort of rattling legend", adding: "Love you a lot my friend! (bolly24.com)