Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.
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.
Increased intracellular or extracellular fluid in brain tissue. Cytotoxic brain edema (swelling due to increased intracellular fluid) is indicative of a disturbance in cell metabolism, and is commonly associated with hypoxic or ischemic injuries (see HYPOXIA, BRAIN). An increase in extracellular fluid may be caused by increased brain capillary permeability (vasogenic edema), an osmotic gradient, local blockages in interstitial fluid pathways, or by obstruction of CSF flow (e.g., obstructive HYDROCEPHALUS). (From Childs Nerv Syst 1992 Sep; 8(6):301-6)
The passage of cells across the layer of ENDOTHELIAL CELLS, i.e., the ENDOTHELIUM; or across the layer of EPITHELIAL CELLS, i.e. the EPITHELIUM.
A MARVEL domain protein that plays an important role in the formation and regulation of the TIGHT JUNCTION paracellular permeability barrier.
Acute and chronic (see also BRAIN INJURIES, CHRONIC) injuries to the brain, including the cerebral hemispheres, CEREBELLUM, and BRAIN STEM. Clinical manifestations depend on the nature of injury. Diffuse trauma to the brain is frequently associated with DIFFUSE AXONAL INJURY or COMA, POST-TRAUMATIC. Localized injuries may be associated with NEUROBEHAVIORAL MANIFESTATIONS; HEMIPARESIS, or other focal neurologic deficits.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Highly specialized EPITHELIAL CELLS that line the HEART; BLOOD VESSELS; and lymph vessels, forming the ENDOTHELIUM. They are polygonal in shape and joined together by TIGHT JUNCTIONS. The tight junctions allow for variable permeability to specific macromolecules that are transported across the endothelial layer.
The property of blood capillary ENDOTHELIUM that allows for the selective exchange of substances between the blood and surrounding tissues and through membranous barriers such as the BLOOD-AIR BARRIER; BLOOD-AQUEOUS BARRIER; BLOOD-BRAIN BARRIER; BLOOD-NERVE BARRIER; BLOOD-RETINAL BARRIER; and BLOOD-TESTIS BARRIER. Small lipid-soluble molecules such as carbon dioxide and oxygen move freely by diffusion. Water and water-soluble molecules cannot pass through the endothelial walls and are dependent on microscopic pores. These pores show narrow areas (TIGHT JUNCTIONS) which may limit large molecule movement.
An azo dye used in blood volume and cardiac output measurement by the dye dilution method. It is very soluble, strongly bound to plasma albumin, and disappears very slowly.
Cell-cell junctions that seal adjacent epithelial cells together, preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other. (Alberts et al., Molecular Biology of the Cell, 2nd ed, p22)
The finer blood vessels of the vasculature that are generally less than 100 microns in internal diameter.
Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.
A specific blocker of dopamine receptors. It speeds gastrointestinal peristalsis, causes prolactin release, and is used as antiemetic and tool in the study of dopaminergic mechanisms.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
Inflammation of the BRAIN due to infection, autoimmune processes, toxins, and other conditions. Viral infections (see ENCEPHALITIS, VIRAL) are a relatively frequent cause of this condition.
A class of large neuroglial (macroglial) cells in the central nervous system - the largest and most numerous neuroglial cells in the brain and spinal cord. Astrocytes (from "star" cells) are irregularly shaped with many long processes, including those with "end feet" which form the glial (limiting) membrane and directly and indirectly contribute to the BLOOD-BRAIN BARRIER. They regulate the extracellular ionic and chemical environment, and "reactive astrocytes" (along with MICROGLIA) respond to injury.
The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
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.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
Drugs intended to prevent damage to the brain or spinal cord from ischemia, stroke, convulsions, or trauma. Some must be administered before the event, but others may be effective for some time after. They act by a variety of mechanisms, but often directly or indirectly minimize the damage produced by endogenous excitatory amino acids.
Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.
Forceful administration into the peritoneal cavity of liquid medication, nutrient, or other fluid through a hollow needle piercing the abdominal wall.
The third type of glial cell, along with astrocytes and oligodendrocytes (which together form the macroglia). Microglia vary in appearance depending on developmental stage, functional state, and anatomical location; subtype terms include ramified, perivascular, ameboid, resting, and activated. Microglia clearly are capable of phagocytosis and play an important role in a wide spectrum of neuropathologies. They have also been suggested to act in several other roles including in secretion (e.g., of cytokines and neural growth factors), in immunological processing (e.g., antigen presentation), and in central nervous system development and remodeling.
A villous structure of tangled masses of BLOOD VESSELS contained within the third, lateral, and fourth ventricles of the BRAIN. It regulates part of the production and composition of CEREBROSPINAL FLUID.
Elements of limited time intervals, contributing to particular results or situations.
The non-neuronal cells of the nervous system. They not only provide physical support, but also respond to injury, regulate the ionic and chemical composition of the extracellular milieu, participate in the BLOOD-BRAIN BARRIER and BLOOD-RETINAL BARRIER, form the myelin insulation of nervous pathways, guide neuronal migration during development, and exchange metabolites with neurons. Neuroglia have high-affinity transmitter uptake systems, voltage-dependent and transmitter-gated ion channels, and can release transmitters, but their role in signaling (as in many other functions) is unclear.
A 170-kDa transmembrane glycoprotein from the superfamily of ATP-BINDING CASSETTE TRANSPORTERS. It serves as an ATP-dependent efflux pump for a variety of chemicals, including many ANTINEOPLASTIC AGENTS. Overexpression of this glycoprotein is associated with multidrug resistance (see DRUG RESISTANCE, MULTIPLE).
A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.
Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
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)
White blood cells. These include granular leukocytes (BASOPHILS; EOSINOPHILS; and NEUTROPHILS) as well as non-granular leukocytes (LYMPHOCYTES and MONOCYTES).
Peptides generated from AMYLOID BETA-PEPTIDES PRECURSOR. An amyloid fibrillar form of these peptides is the major component of amyloid plaques found in individuals with Alzheimer's disease and in aged individuals with trisomy 21 (DOWN SYNDROME). The peptide is found predominantly in the nervous system, but there have been reports of its presence in non-neural tissue.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Isomeric forms and derivatives of octanol (C8H17OH).
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
A degenerative disease of the BRAIN characterized by the insidious onset of DEMENTIA. Impairment of MEMORY, judgment, attention span, and problem solving skills are followed by severe APRAXIAS and a global loss of cognitive abilities. The condition primarily occurs after age 60, and is marked pathologically by severe cortical atrophy and the triad of SENILE PLAQUES; NEUROFIBRILLARY TANGLES; and NEUROPIL THREADS. (From Adams et al., Principles of Neurology, 6th ed, pp1049-57)
The relationship between the dose of an administered drug and the response of the organism to the drug.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.
A watery fluid that is continuously produced in the CHOROID PLEXUS and circulates around the surface of the BRAIN; SPINAL CORD; and in the CEREBRAL VENTRICLES.
NECROSIS occurring in the MIDDLE CEREBRAL ARTERY distribution system which brings blood to the entire lateral aspects of each CEREBRAL HEMISPHERE. Clinical signs include impaired cognition; APHASIA; AGRAPHIA; weak and numbness in the face and arms, contralaterally or bilaterally depending on the infarction.
The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
The circulation of blood through the BLOOD VESSELS of the BRAIN.
An endopeptidase that is structurally similar to MATRIX METALLOPROTEINASE 2. It degrades GELATIN types I and V; COLLAGEN TYPE IV; and COLLAGEN TYPE V.
A specialized transport barrier, in the EYE, formed by the retinal pigment EPITHELIUM, and the ENDOTHELIUM of the BLOOD VESSELS of the RETINA. TIGHT JUNCTIONS joining adjacent cells keep the barrier between cells continuous.
A circumscribed collection of purulent exudate in the brain, due to bacterial and other infections. The majority are caused by spread of infected material from a focus of suppuration elsewhere in the body, notably the PARANASAL SINUSES, middle ear (see EAR, MIDDLE); HEART (see also ENDOCARDITIS, BACTERIAL), and LUNG. Penetrating CRANIOCEREBRAL TRAUMA and NEUROSURGICAL PROCEDURES may also be associated with this condition. Clinical manifestations include HEADACHE; SEIZURES; focal neurologic deficits; and alterations of consciousness. (Adams et al., Principles of Neurology, 6th ed, pp712-6)
The barrier between capillary blood and alveolar air comprising the alveolar EPITHELIUM and capillary ENDOTHELIUM with their adherent BASEMENT MEMBRANE and EPITHELIAL CELL cytoplasm. PULMONARY GAS EXCHANGE occurs across this membrane.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Substances used to allow enhanced visualization of tissues.
Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
A specialized barrier, in the TESTIS, between the interstitial BLOOD compartment and the adluminal compartment of the SEMINIFEROUS TUBULES. The barrier is formed by layers of cells from the VASCULAR ENDOTHELIUM of the capillary BLOOD VESSELS, to the SEMINIFEROUS EPITHELIUM of the seminiferous tubules. TIGHT JUNCTIONS form between adjacent SERTOLI CELLS, as well as between the ENDOTHELIAL CELLS.
Those factors, such as language or sociocultural relationships, which interfere in the meaningful interpretation and transmission of ideas between individuals or groups.

Involvement of tumor necrosis factor alpha and interleukin-1beta in enhancement of pentylenetetrazole-induced seizures caused by Shigella dysenteriae. (1/3796)

Neurologic manifestations, mainly convulsions, are the most frequent extraintestinal complications of shigellosis. We used an animal model to study the roles of tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) in Shigella-related seizures. Administration of Shigella dysenteriae 60R sonicate enhanced the sensitivity of mice to the proconvulsant pentylenetetrazole (PTZ) within 7 h. This was indicated by a significantly higher mean convulsion score and an increased number of mice responding with clonic-tonic seizures in the Shigella-pretreated group. Preinjection of mice with anti-murine TNF-alpha (anti-mTNF-alpha) or anti-murine IL-1beta (anti-mIL-1beta) 30 min prior to administration of Shigella sonicate abolished their enhanced response to PTZ at 7 h. Mean convulsion scores were reduced by anti-mTNF-alpha from 1.2 to 0.8 (P = 0.017) and by anti-mIL-1beta from 1.3 to 0.7 (P = 0.008). Preinjection of anti-mTNF-alpha also reduced the percentage of mice responding with clonic-tonic seizures, from 48 to 29% (P = 0.002), and preinjection of anti-mIL-1beta reduced it from 53 to 21% (P = 0. 012). Neutralization of TNF-alpha or IL-1beta did not protect the mice from death due to S. dysenteriae 60R. These findings indicate that TNF-alpha and IL-1beta play a role in the very early sensitization of the central nervous system to convulsive activity after S. dysenteriae administration. Similar mechanisms may trigger neurologic disturbances in other infectious diseases.  (+info)

Drug-protein binding and blood-brain barrier permeability. (2/3796)

The permeability surface area (PS) product, an index of permeability of the blood-brain barrier (BBB), was measured by using the in situ perfusion method. In the cerebral circulation, the fraction of drug that permeates into the brain through the BBB is not only the unbound fraction but also the fraction dissociated from the protein in the perfusate. The sum of these two fractions, the apparent exchangeable fraction, was estimated by fitting the parameters of the BBB permeability under the condition of varying BSA concentrations in the perfusate. The unbound fraction of drugs in a buffer containing 0.5 mM BSA was measured by using the ultrafiltration method in vitro, and the apparent exchangeable fraction was measured in vivo by using the intracarotid artery injection method. The apparent exchange fraction was 100% for S-8510, 96.5% for diazepam, 90.9% for caffeine, 38.3% for S-312-d, 33.1% for propranolol, and 6.68% for (+)-S-145 Na, and each of these was higher than the corresponding unbound fraction in vitro in all drugs. The apparent exchangeable fractions, for example, were 8 times higher for diazepam and 38 times for S-312-d than the unbound fractions in vitro. The apparent exchangeable fraction of drugs was also estimated from the parameters obtained with the perfusion method. Because drugs can be infused for an arbitrary length of time in the perfusion method, substances with low permeability can be measured. The apparent exchangeable fractions obtained with this method were almost the same as those obtained with the intracarotid artery injection method.  (+info)

Novel, highly lipophilic antioxidants readily diffuse across the blood-brain barrier and access intracellular sites. (3/3796)

In an accompanying article, an in vitro assay for permeability predicts that membrane-protective, antioxidant 2,4-diamino-pyrrolo[2, 3-d]pyrimidines should have improved blood-brain barrier (BBB) permeation over previously described lipophilic antioxidants. Using a first-pass extraction method and brain/plasma quantification, we show here that two of the pyrrolopyrimidines, one of which is markedly less permeable, readily partition into rat brain. The efficiency of extraction was dependent on serum protein binding, and in situ efflux confirms the in vitro data showing that PNU-87663 is retained in brain longer than PNU-89843. By exploiting inherent fluorescence properties of PNU-87663, its distribution within brain and within cells in culture was demonstrated using confocal scanning laser microscopy. PNU-87663 rapidly partitioned into the cell membrane and equilibrates with cytoplasmic compartments via passive diffusion. Although partitioning of PNU-87663 favors intracytoplasmic lipid storage droplets, the compound was readily exchangeable as shown by efflux of compound from cells to buffer when protein was present. The results demonstrated that pyrrolopyrimidines were well suited for quickly accessing target cells within the central nervous system as well as in other target tissues.  (+info)

Inhibition by lead of production and secretion of transthyretin in the choroid plexus: its relation to thyroxine transport at blood-CSF barrier. (4/3796)

Long-term, low-dose Pb exposure in rats is associated with a significant decrease in transthyretin (TTR) concentrations in the CSF. Since CSF TTR, a primary carrier of thyroxine in brain, is produced and secreted by the choroid plexus, in vitro studies were conducted to test whether Pb exposure interferes with TTR production and/or secretion by the choroid plexus, leading to an impaired thyroxine transport at the blood-CSF barrier. Newly synthesized TTR molecules in the cultured choroidal epithelial cells were pulse-labeled with [35S]methionine. [35S]TTR in the cell lysates and culture media was immunoprecipitated and separated by SDS-PAGE, and quantitated by autoradiography and liquid scintillation counting. Pb treatment did not significantly alter the protein concentrations in the culture, but inhibited the synthesis of total [35S]TTR (cells + media), particularly during the later chase phase. Two-way ANOVA of the chase phase revealed that Pb exposure (30 microM) significantly suppressed the rate of secretion of [35S]TTR compared to the controls (p < 0.05). Accordingly, Pb treatment caused a retention of [35S]TTR by the cells. In a two-chamber transport system with a monolayer of epithelial barrier, Pb exposure (30 microM) reduced the initial release rate constant (kr) of [125I]T4 from the cell monolayer to the culture media and impeded the transepithelial transport of [125I]T4 from the basal to apical side of epithelial cells by 27%. Taken together, these in vitro data suggest that sequestration of Pb in the choroid plexus hinders the production and secretion of TTR by this tissue. Consequently, this may alter the transport of thyroxine across this blood-CSF barrier.  (+info)

Receptor-mediated transcytosis of lactoferrin through the blood-brain barrier. (5/3796)

Lactoferrin (Lf) is an iron-binding protein involved in host defense against infection and severe inflammation; it accumulates in the brain during neurodegenerative disorders. Before determining Lf function in brain tissue, we investigated its origin and demonstrate here that it crosses the blood-brain barrier. An in vitro model of the blood-brain barrier was used to examine the mechanism of Lf transport to the brain. We report that differentiated bovine brain capillary endothelial cells exhibited specific high (Kd = 37.5 nM; n = 90,000/cell) and low (Kd = 2 microM; n = 900,000 sites/cell) affinity binding sites. Only the latter were present on nondifferentiated cells. The surface-bound Lf was internalized only by the differentiated cell population leading to the conclusion that Lf receptors were acquired during cell differentiation. A specific unidirectional transport then occurred via a receptor-mediated process with no apparent intraendothelial degradation. We further report that iron may cross the bovine brain capillary endothelial cells as a complex with Lf. Finally, we show that the low density lipoprotein receptor-related protein might be involved in this process because its specific antagonist, the receptor-associated protein, inhibits 70% of Lf transport.  (+info)

Nonsaturable entry of neuropeptide Y into brain. (6/3796)

Neuropeptide Y (NPY) is found and is active both in the periphery and brain, but its crossing of the blood-brain barrier (BBB) in either direction has not been measured. We used multiple time-regression analysis to determine that radioactively labeled NPY injected intravenously entered the brain much faster than albumin, with an influx constant of 2.0 x 10(-4) ml. g. -1. min-1. However, this rate of entry was not significantly changed by injection of 10 microgram/mouse of excess NPY, by leptin, or by food deprivation. HPLC showed that most of the NPY entering the brain was intact, and capillary depletion with and without washout showed that the NPY did not remain bound to endothelial cells or associated with vascular elements. Perfusion in a blood-free solution eliminated binding to serum proteins as an explanation for the lack of saturation. Efflux of labeled NPY from the brain occurred at the same rate as albumin, reflecting the normal rate of reabsorption of cerebrospinal fluid. Thus NPY can readily enter the brain from blood by diffusion across the BBB.  (+info)

Selective delivery of herpes virus vectors to experimental brain tumors using RMP-7. (7/3796)

RMP-7, a bradykinin analog, has been shown to selectively open the blood-tumor barrier for the delivery of chemotherapeutic drugs to brain tumors. In contrast to bradykinin, RMP-7 has no hypotensive effects and has been approved for human use. This study was initiated to determine whether RMP-7 would open the blood-tumor barrier to virus vectors encoding tumor-killing genes in an experimental model. The herpes virus vector used, hrR3, which encodes virus thymidine kinase gene and the lacZ reporter gene, is defective in a gene encoding ribonucleotide reductase, replicates selectively in dividing tumor cells and not in postmitotic neural cells. It was determined that an optimum dose of RMP-7 (1.5-3.0 microg/kg over 10-15 minutes) enhanced viral delivery to brain tumors in rats bearing intracranial 9 L gliosarcomas when infused through the carotid artery immediately prior to virus vector application. Maximum expression of the lacZ reporter gene occurred at 3 days after intracarotid infusion. By 8 days, transgene expression was largely confined to tumor foci away from the main tumor mass. Viral delivery was essentially specific to tumor cells, with little transgene expression elsewhere in the brain. Minimal uptake and pathology was noted in the kidney, spleen, and liver. These findings indicate that intracarotid delivery of RMP-7 can augment the selective delivery of virus vectors to brain tumors in an experimental rat model, with the potential for application to human brain tumors.  (+info)

Orexin A but not orexin B rapidly enters brain from blood by simple diffusion. (8/3796)

We determined the ability of orexin A and orexin B, recently discovered endogenous appetite enhancers, to cross the blood-brain barrier (BBB) of mice. Multiple time-regression analysis showed that an i.v. bolus of 125I-orexin A rapidly entered the brain from the blood, with an influx rate (Ki = 2.5 +/- 0.3 x 10(-4) ml/g.min) many times faster than that of the 99mTc-albumin control. This relatively rapid rate of entry was not reduced by administration of excess orexin A (or leptin) or by fasting for 22 h, even when penetration into only the hypothalamus was measured. Lack of saturability also was shown by perfusion in blood-free buffer. HPLC revealed that most of the injected 125I-orexin A reached the brain as intact peptide. Capillary depletion studies showed that the administered peptide did not remain bound to the endothelial cells comprising the BBB but reached the brain parenchyma. Efflux of 125I-orexin A from the brain occurred at the same rate as 99mTc-albumin. The octanol/buffer partition coefficient of 0.232 showed that orexin A was highly lipophilic, whereas the value for orexin B was only 0.030. Orexin B, moreover, was rapidly degraded in blood, so no 125I-orexin B could be detected in intact form in brain when injected peripherally. Thus, although orexin B is rapidly metabolized in blood and has low lipophilicity, orexin A rapidly crosses the BBB from blood to reach brain tissue by the process of simple diffusion.  (+info)

The Blood-Brain Barrier (BBB) is a highly specialized, selective interface between the central nervous system (CNS) and the circulating blood. It is formed by unique endothelial cells that line the brain's capillaries, along with tight junctions, astrocytic foot processes, and pericytes, which together restrict the passage of substances from the bloodstream into the CNS. This barrier serves to protect the brain from harmful agents and maintain a stable environment for proper neural function. However, it also poses a challenge in delivering therapeutics to the CNS, as most large and hydrophilic molecules cannot cross the BBB.

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.

Brain edema is a medical condition characterized by the abnormal accumulation of fluid in the brain, leading to an increase in intracranial pressure. This can result from various causes, such as traumatic brain injury, stroke, infection, brain tumors, or inflammation. The swelling of the brain can compress vital structures, impair blood flow, and cause neurological symptoms, which may range from mild headaches to severe cognitive impairment, seizures, coma, or even death if not treated promptly and effectively.

Transendothelial migration (TEM) and transepithelial migration (TRM) are terms used to describe the movement of cells, typically leukocytes (white blood cells), across endothelial or epithelial cell layers. These processes play a crucial role in immune surveillance and inflammation.

Transendothelial migration refers specifically to the movement of cells across the endothelium, which is the layer of cells that lines the interior surface of blood vessels. This process allows leukocytes to leave the bloodstream and enter surrounding tissues during an immune response. TEM can be further divided into two main steps:

1. Adhesion: The initial attachment of leukocytes to the endothelium, mediated by adhesion molecules expressed on both the leukocyte and endothelial cell surfaces.
2. Diapedesis: The transmigration step where leukocytes squeeze between adjacent endothelial cells and move through the basement membrane to reach the underlying tissue.

Transepithelial migration, on the other hand, refers to the movement of cells across an epithelium, which is a layer of cells that forms a barrier between a body cavity or lumen (such as the gut or airways) and the underlying tissue. TRM can be observed in various physiological processes like wound healing and immune cell trafficking, but it also plays a role in pathological conditions such as cancer metastasis. Similar to TEM, TRM can be divided into several steps:

1. Adhesion: The initial attachment of cells to the epithelium, facilitated by adhesion molecules and receptors.
2. Polarization: Cells become polarized, forming protrusions that help them navigate through the tight junctions between epithelial cells.
3. Diapedesis: The transmigration step where cells move across the epithelium, often involving the disassembly and reassembly of tight junctions between epithelial cells.
4. Re-epithelialization: After cell migration is complete, the epithelial layer needs to be restored by re-establishing tight junctions and maintaining barrier integrity.

Occludin is a protein that is a component of tight junctions, which are structures that form a barrier between adjacent cells in epithelial and endothelial tissues. Tight junctions help to regulate the movement of molecules between cells and play a crucial role in maintaining the integrity of these tissues.

Occludin is composed of four transmembrane domains, two extracellular loops, and intracellular N- and C-termini. The extracellular loops interact with other tight junction proteins to form the intercellular seal, while the intracellular domains interact with various signaling molecules and cytoskeletal components to regulate the assembly and disassembly of tight junctions.

Mutations in the gene that encodes occludin have been associated with various human diseases, including inflammatory bowel disease, liver cirrhosis, and skin disorders. Additionally, changes in occludin expression and localization have been implicated in the development of cancer and neurological disorders.

A brain injury is defined as damage to the brain that occurs following an external force or trauma, such as a blow to the head, a fall, or a motor vehicle accident. Brain injuries can also result from internal conditions, such as lack of oxygen or a stroke. There are two main types of brain injuries: traumatic and acquired.

Traumatic brain injury (TBI) is caused by an external force that results in the brain moving within the skull or the skull being fractured. Mild TBIs may result in temporary symptoms such as headaches, confusion, and memory loss, while severe TBIs can cause long-term complications, including physical, cognitive, and emotional impairments.

Acquired brain injury (ABI) is any injury to the brain that occurs after birth and is not hereditary, congenital, or degenerative. ABIs are often caused by medical conditions such as strokes, tumors, anoxia (lack of oxygen), or infections.

Both TBIs and ABIs can range from mild to severe and may result in a variety of physical, cognitive, and emotional symptoms that can impact a person's ability to perform daily activities and function independently. Treatment for brain injuries typically involves a multidisciplinary approach, including medical management, rehabilitation, and supportive care.

In the context of medicine and physiology, permeability refers to the ability of a tissue or membrane to allow the passage of fluids, solutes, or gases. It is often used to describe the property of the capillary walls, which control the exchange of substances between the blood and the surrounding tissues.

The permeability of a membrane can be influenced by various factors, including its molecular structure, charge, and the size of the molecules attempting to pass through it. A more permeable membrane allows for easier passage of substances, while a less permeable membrane restricts the movement of substances.

In some cases, changes in permeability can have significant consequences for health. For example, increased permeability of the blood-brain barrier (a specialized type of capillary that regulates the passage of substances into the brain) has been implicated in a number of neurological conditions, including multiple sclerosis, Alzheimer's disease, and traumatic brain injury.

Endothelial cells are the type of cells that line the inner surface of blood vessels, lymphatic vessels, and heart chambers. They play a crucial role in maintaining vascular homeostasis by controlling vasomotor tone, coagulation, platelet activation, and inflammation. Endothelial cells also regulate the transport of molecules between the blood and surrounding tissues, and contribute to the maintenance of the structural integrity of the vasculature. They are flat, elongated cells with a unique morphology that allows them to form a continuous, nonthrombogenic lining inside the vessels. Endothelial cells can be isolated from various tissues and cultured in vitro for research purposes.

Capillary permeability refers to the ability of substances to pass through the walls of capillaries, which are the smallest blood vessels in the body. These tiny vessels connect the arterioles and venules, allowing for the exchange of nutrients, waste products, and gases between the blood and the surrounding tissues.

The capillary wall is composed of a single layer of endothelial cells that are held together by tight junctions. The permeability of these walls varies depending on the size and charge of the molecules attempting to pass through. Small, uncharged molecules such as water, oxygen, and carbon dioxide can easily diffuse through the capillary wall, while larger or charged molecules such as proteins and large ions have more difficulty passing through.

Increased capillary permeability can occur in response to inflammation, infection, or injury, allowing larger molecules and immune cells to enter the surrounding tissues. This can lead to swelling (edema) and tissue damage if not controlled. Decreased capillary permeability, on the other hand, can lead to impaired nutrient exchange and tissue hypoxia.

Overall, the permeability of capillaries is a critical factor in maintaining the health and function of tissues throughout the body.

Evans Blue is not a medical condition or diagnosis, but rather a dye that is used in medical research and tests. It is a dark blue dye that binds to albumin (a type of protein) in the bloodstream. This complex is too large to pass through the walls of capillaries, so it remains in the blood vessels and does not enter the surrounding tissues. As a result, Evans Blue can be used as a marker to visualize or measure the volume of the circulatory system.

In research settings, Evans Blue is sometimes used in studies involving the brain and nervous system. For example, it may be injected into the cerebrospinal fluid (the fluid that surrounds the brain and spinal cord) to help researchers see the distribution of this fluid in the brain. It can also be used to study blood-brain barrier function, as changes in the permeability of the blood-brain barrier can allow Evans Blue to leak into the brain tissue.

It is important to note that Evans Blue should only be used under the supervision of a trained medical professional, as it can be harmful if ingested or inhaled.

Tight junctions, also known as zonula occludens, are specialized types of intercellular junctions that occur in epithelial and endothelial cells. They are located near the apical side of the lateral membranes of adjacent cells, where they form a continuous belt-like structure that seals off the space between the cells.

Tight junctions are composed of several proteins, including occludin, claudins, and junctional adhesion molecules (JAMs), which interact to form a network of strands that create a tight barrier. This barrier regulates the paracellular permeability of ions, solutes, and water, preventing their uncontrolled movement across the epithelial or endothelial layer.

Tight junctions also play an important role in maintaining cell polarity by preventing the mixing of apical and basolateral membrane components. Additionally, they are involved in various signaling pathways that regulate cell proliferation, differentiation, and survival.

Microvessels are the smallest blood vessels in the body, including capillaries, venules, and arterioles. They form a crucial part of the circulatory system, responsible for delivering oxygen and nutrients to tissues and organs while removing waste products. Capillaries, the tiniest microvessels, facilitate the exchange of substances between blood and tissue cells through their thin walls. Overall, microvessels play a vital role in maintaining proper organ function and overall health.

Brain neoplasms, also known as brain tumors, are abnormal growths of cells within the brain. These growths can be benign (non-cancerous) or malignant (cancerous). Benign brain tumors typically grow slowly and do not spread to other parts of the body. However, they can still cause serious problems if they press on sensitive areas of the brain. Malignant brain tumors, on the other hand, are cancerous and can grow quickly, invading surrounding brain tissue and spreading to other parts of the brain or spinal cord.

Brain neoplasms can arise from various types of cells within the brain, including glial cells (which provide support and insulation for nerve cells), neurons (nerve cells that transmit signals in the brain), and meninges (the membranes that cover the brain and spinal cord). They can also result from the spread of cancer cells from other parts of the body, known as metastatic brain tumors.

Symptoms of brain neoplasms may vary depending on their size, location, and growth rate. Common symptoms include headaches, seizures, weakness or paralysis in the limbs, difficulty with balance and coordination, changes in speech or vision, confusion, memory loss, and changes in behavior or personality.

Treatment for brain neoplasms depends on several factors, including the type, size, location, and grade of the tumor, as well as the patient's age and overall health. Treatment options may include surgery, radiation therapy, chemotherapy, targeted therapy, or a combination of these approaches. Regular follow-up care is essential to monitor for recurrence and manage any long-term effects of treatment.

Domperidone is a medication that belongs to the class of dopamine antagonists. It works by blocking the action of dopamine, a chemical in the brain that can cause nausea and vomiting. Domperidone is primarily used to treat symptoms of gastroesophageal reflux disease (GERD) and gastric motility disorders, including bloating, fullness, and regurgitation. It works by increasing the contractions of the stomach muscles, which helps to move food and digestive juices through the stomach more quickly.

Domperidone is available in various forms, such as tablets, suspension, and injection. The medication is generally well-tolerated, but it can cause side effects such as dry mouth, diarrhea, headache, and dizziness. In rare cases, domperidone may cause more serious side effects, including irregular heart rhythms, tremors, or muscle stiffness.

It is important to note that domperidone has a risk of causing cardiac arrhythmias, particularly at higher doses and in patients with pre-existing heart conditions. Therefore, it should be used with caution and only under the supervision of a healthcare professional.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

Encephalitis is defined as inflammation of the brain parenchyma, which is often caused by viral infections but can also be due to bacterial, fungal, or parasitic infections, autoimmune disorders, or exposure to toxins. The infection or inflammation can cause various symptoms such as headache, fever, confusion, seizures, and altered consciousness, ranging from mild symptoms to severe cases that can lead to brain damage, long-term disabilities, or even death.

The diagnosis of encephalitis typically involves a combination of clinical evaluation, imaging studies (such as MRI or CT scans), and laboratory tests (such as cerebrospinal fluid analysis). Treatment may include antiviral medications, corticosteroids, immunoglobulins, and supportive care to manage symptoms and prevent complications.

Astrocytes are a type of star-shaped glial cell found in the central nervous system (CNS), including the brain and spinal cord. They play crucial roles in supporting and maintaining the health and function of neurons, which are the primary cells responsible for transmitting information in the CNS.

Some of the essential functions of astrocytes include:

1. Supporting neuronal structure and function: Astrocytes provide structural support to neurons by ensheathing them and maintaining the integrity of the blood-brain barrier, which helps regulate the entry and exit of substances into the CNS.
2. Regulating neurotransmitter levels: Astrocytes help control the levels of neurotransmitters in the synaptic cleft (the space between two neurons) by taking up excess neurotransmitters and breaking them down, thus preventing excessive or prolonged activation of neuronal receptors.
3. Providing nutrients to neurons: Astrocytes help supply energy metabolites, such as lactate, to neurons, which are essential for their survival and function.
4. Modulating synaptic activity: Through the release of various signaling molecules, astrocytes can modulate synaptic strength and plasticity, contributing to learning and memory processes.
5. Participating in immune responses: Astrocytes can respond to CNS injuries or infections by releasing pro-inflammatory cytokines and chemokines, which help recruit immune cells to the site of injury or infection.
6. Promoting neuronal survival and repair: In response to injury or disease, astrocytes can become reactive and undergo morphological changes that aid in forming a glial scar, which helps contain damage and promote tissue repair. Additionally, they release growth factors and other molecules that support the survival and regeneration of injured neurons.

Dysfunction or damage to astrocytes has been implicated in several neurological disorders, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS).

The Central Nervous System (CNS) is the part of the nervous system that consists of the brain and spinal cord. It is called the "central" system because it receives information from, and sends information to, the rest of the body through peripheral nerves, which make up the Peripheral Nervous System (PNS).

The CNS is responsible for processing sensory information, controlling motor functions, and regulating various autonomic processes like heart rate, respiration, and digestion. The brain, as the command center of the CNS, interprets sensory stimuli, formulates thoughts, and initiates actions. The spinal cord serves as a conduit for nerve impulses traveling to and from the brain and the rest of the body.

The CNS is protected by several structures, including the skull (which houses the brain) and the vertebral column (which surrounds and protects the spinal cord). Despite these protective measures, the CNS remains vulnerable to injury and disease, which can have severe consequences due to its crucial role in controlling essential bodily functions.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

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.

Medical Definition:

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.

Neuroprotective agents are substances that protect neurons or nerve cells from damage, degeneration, or death caused by various factors such as trauma, inflammation, oxidative stress, or excitotoxicity. These agents work through different mechanisms, including reducing the production of free radicals, inhibiting the release of glutamate (a neurotransmitter that can cause cell damage in high concentrations), promoting the growth and survival of neurons, and preventing apoptosis (programmed cell death). Neuroprotective agents have been studied for their potential to treat various neurological disorders, including stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, and multiple sclerosis. However, more research is needed to fully understand their mechanisms of action and to develop effective therapies.

Nanoparticles are defined in the field of medicine as tiny particles that have at least one dimension between 1 to 100 nanometers (nm). They are increasingly being used in various medical applications such as drug delivery, diagnostics, and therapeutics. Due to their small size, nanoparticles can penetrate cells, tissues, and organs more efficiently than larger particles, making them ideal for targeted drug delivery and imaging.

Nanoparticles can be made from a variety of materials including metals, polymers, lipids, and dendrimers. The physical and chemical properties of nanoparticles, such as size, shape, charge, and surface chemistry, can greatly affect their behavior in biological systems and their potential medical applications.

It is important to note that the use of nanoparticles in medicine is still a relatively new field, and there are ongoing studies to better understand their safety and efficacy.

C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.

The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.

C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.

One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.

Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.

Drug delivery systems (DDS) refer to techniques or technologies that are designed to improve the administration of a pharmaceutical compound in terms of its efficiency, safety, and efficacy. A DDS can modify the drug release profile, target the drug to specific cells or tissues, protect the drug from degradation, and reduce side effects.

The goal of a DDS is to optimize the bioavailability of a drug, which is the amount of the drug that reaches the systemic circulation and is available at the site of action. This can be achieved through various approaches, such as encapsulating the drug in a nanoparticle or attaching it to a biomolecule that targets specific cells or tissues.

Some examples of DDS include:

1. Controlled release systems: These systems are designed to release the drug at a controlled rate over an extended period, reducing the frequency of dosing and improving patient compliance.
2. Targeted delivery systems: These systems use biomolecules such as antibodies or ligands to target the drug to specific cells or tissues, increasing its efficacy and reducing side effects.
3. Nanoparticle-based delivery systems: These systems use nanoparticles made of polymers, lipids, or inorganic materials to encapsulate the drug and protect it from degradation, improve its solubility, and target it to specific cells or tissues.
4. Biodegradable implants: These are small devices that can be implanted under the skin or into body cavities to deliver drugs over an extended period. They can be made of biodegradable materials that gradually break down and release the drug.
5. Inhalation delivery systems: These systems use inhalers or nebulizers to deliver drugs directly to the lungs, bypassing the digestive system and improving bioavailability.

Overall, DDS play a critical role in modern pharmaceutical research and development, enabling the creation of new drugs with improved efficacy, safety, and patient compliance.

"Intraperitoneal injection" is a medical term that refers to the administration of a substance or medication directly into the peritoneal cavity, which is the space between the lining of the abdominal wall and the organs contained within it. This type of injection is typically used in clinical settings for various purposes, such as delivering chemotherapy drugs, anesthetics, or other medications directly to the abdominal organs.

The procedure involves inserting a needle through the abdominal wall and into the peritoneal cavity, taking care to avoid any vital structures such as blood vessels or nerves. Once the needle is properly positioned, the medication can be injected slowly and carefully to ensure even distribution throughout the cavity.

It's important to note that intraperitoneal injections are typically reserved for situations where other routes of administration are not feasible or effective, as they carry a higher risk of complications such as infection, bleeding, or injury to surrounding organs. As with any medical procedure, it should only be performed by trained healthcare professionals under appropriate clinical circumstances.

Microglia are a type of specialized immune cell found in the brain and spinal cord. They are part of the glial family, which provide support and protection to the neurons in the central nervous system (CNS). Microglia account for about 10-15% of all cells found in the CNS.

The primary role of microglia is to constantly survey their environment and eliminate any potentially harmful agents, such as pathogens, dead cells, or protein aggregates. They do this through a process called phagocytosis, where they engulf and digest foreign particles or cellular debris. In addition to their phagocytic function, microglia also release various cytokines, chemokines, and growth factors that help regulate the immune response in the CNS, promote neuronal survival, and contribute to synaptic plasticity.

Microglia can exist in different activation states depending on the nature of the stimuli they encounter. In a resting state, microglia have a small cell body with numerous branches that are constantly monitoring their surroundings. When activated by an injury, infection, or neurodegenerative process, microglia change their morphology and phenotype, retracting their processes and adopting an amoeboid shape to migrate towards the site of damage or inflammation. Based on the type of activation, microglia can release both pro-inflammatory and anti-inflammatory factors that contribute to either neuroprotection or neurotoxicity.

Dysregulation of microglial function has been implicated in several neurological disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and Amyotrophic Lateral Sclerosis (ALS). Therefore, understanding the role of microglia in health and disease is crucial for developing novel therapeutic strategies to treat these conditions.

The choroid plexus is a network of blood vessels and tissue located within each ventricle (fluid-filled space) of the brain. It plays a crucial role in the production of cerebrospinal fluid (CSF), which provides protection and nourishment to the brain and spinal cord.

The choroid plexus consists of modified ependymal cells, called plexus epithelial cells, that line the ventricular walls. These cells have finger-like projections called villi, which increase their surface area for efficient CSF production. The blood vessels within the choroid plexus transport nutrients, ions, and water to these epithelial cells, where they are actively secreted into the ventricles to form CSF.

In addition to its role in CSF production, the choroid plexus also acts as a barrier between the blood and the central nervous system (CNS), regulating the exchange of substances between them. This barrier function is primarily attributed to tight junctions present between the epithelial cells, which limit the paracellular movement of molecules.

Abnormalities in the choroid plexus can lead to various neurological conditions, such as hydrocephalus (excessive accumulation of CSF) or certain types of brain tumors.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Neuroglia, also known as glial cells or simply glia, are non-neuronal cells that provide support and protection for neurons in the nervous system. They maintain homeostasis, form myelin sheaths around nerve fibers, and provide structural support. They also play a role in the immune response of the central nervous system. Some types of neuroglia include astrocytes, oligodendrocytes, microglia, and ependymal cells.

P-glycoprotein (P-gp) is a type of membrane transport protein that plays a crucial role in the efflux (extrusion) of various substrates, including drugs and toxins, out of cells. It is also known as multidrug resistance protein 1 (MDR1).

P-gp is encoded by the ABCB1 gene and is primarily located on the apical membrane of epithelial cells in several tissues, such as the intestine, liver, kidney, and blood-brain barrier. Its main function is to protect these organs from harmful substances by actively pumping them out of the cells and back into the lumen or bloodstream.

In the context of pharmacology, P-gp can contribute to multidrug resistance (MDR) in cancer cells. When overexpressed, P-gp can reduce the intracellular concentration of various anticancer drugs, making them less effective. This has led to extensive research on inhibitors of P-gp as potential adjuvants for cancer therapy.

In summary, P-glycoprotein is a vital efflux transporter that helps maintain homeostasis by removing potentially harmful substances from cells and can impact drug disposition and response in various tissues, including the intestine, liver, kidney, and blood-brain barrier.

Inflammation is a complex biological response of tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. It is characterized by the following signs: rubor (redness), tumor (swelling), calor (heat), dolor (pain), and functio laesa (loss of function). The process involves the activation of the immune system, recruitment of white blood cells, and release of inflammatory mediators, which contribute to the elimination of the injurious stimuli and initiation of the healing process. However, uncontrolled or chronic inflammation can also lead to tissue damage and diseases.

Brain chemistry refers to the chemical processes that occur within the brain, particularly those involving neurotransmitters, neuromodulators, and neuropeptides. These chemicals are responsible for transmitting signals between neurons (nerve cells) in the brain, allowing for various cognitive, emotional, and physical functions.

Neurotransmitters are chemical messengers that transmit signals across the synapse (the tiny gap between two neurons). Examples of neurotransmitters include dopamine, serotonin, norepinephrine, GABA (gamma-aminobutyric acid), and glutamate. Each neurotransmitter has a specific role in brain function, such as regulating mood, motivation, attention, memory, and movement.

Neuromodulators are chemicals that modify the effects of neurotransmitters on neurons. They can enhance or inhibit the transmission of signals between neurons, thereby modulating brain activity. Examples of neuromodulators include acetylcholine, histamine, and substance P.

Neuropeptides are small protein-like molecules that act as neurotransmitters or neuromodulators. They play a role in various physiological functions, such as pain perception, stress response, and reward processing. Examples of neuropeptides include endorphins, enkephalins, and oxytocin.

Abnormalities in brain chemistry can lead to various neurological and psychiatric conditions, such as depression, anxiety disorders, schizophrenia, Parkinson's disease, and Alzheimer's disease. Understanding brain chemistry is crucial for developing effective treatments for these conditions.

Neurons, also known as nerve cells or neurocytes, are specialized cells that constitute the basic unit of the nervous system. They are responsible for receiving, processing, and transmitting information and signals within the body. Neurons have three main parts: the dendrites, the cell body (soma), and the axon. The dendrites receive signals from other neurons or sensory receptors, while the axon transmits these signals to other neurons, muscles, or glands. The junction between two neurons is called a synapse, where neurotransmitters are released to transmit the signal across the gap (synaptic cleft) to the next neuron. Neurons vary in size, shape, and structure depending on their function and location within the nervous system.

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.

Leukocytes, also known as white blood cells (WBCs), are a crucial component of the human immune system. They are responsible for protecting the body against infections and foreign substances. Leukocytes are produced in the bone marrow and circulate throughout the body in the bloodstream and lymphatic system.

There are several types of leukocytes, including:

1. Neutrophils - These are the most abundant type of leukocyte and are primarily responsible for fighting bacterial infections. They contain enzymes that can destroy bacteria.
2. Lymphocytes - These are responsible for producing antibodies and destroying virus-infected cells, as well as cancer cells. There are two main types of lymphocytes: B-lymphocytes and T-lymphocytes.
3. Monocytes - These are the largest type of leukocyte and help to break down and remove dead or damaged tissues, as well as microorganisms.
4. Eosinophils - These play a role in fighting parasitic infections and are also involved in allergic reactions and inflammation.
5. Basophils - These release histamine and other chemicals that cause inflammation in response to allergens or irritants.

An abnormal increase or decrease in the number of leukocytes can indicate an underlying medical condition, such as an infection, inflammation, or a blood disorder.

Amyloid beta-peptides (Aβ) are small protein fragments that are crucially involved in the pathogenesis of Alzheimer's disease. They are derived from a larger transmembrane protein called the amyloid precursor protein (APP) through a series of proteolytic cleavage events.

The two primary forms of Aβ peptides are Aβ40 and Aβ42, which differ in length by two amino acids. While both forms can be harmful, Aβ42 is more prone to aggregation and is considered to be the more pathogenic form. These peptides have the tendency to misfold and accumulate into oligomers, fibrils, and eventually insoluble plaques that deposit in various areas of the brain, most notably the cerebral cortex and hippocampus.

The accumulation of Aβ peptides is believed to initiate a cascade of events leading to neuroinflammation, oxidative stress, synaptic dysfunction, and neuronal death, which are all hallmarks of Alzheimer's disease. Although the exact role of Aβ in the onset and progression of Alzheimer's is still under investigation, it is widely accepted that they play a central part in the development of this debilitating neurodegenerative disorder.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Octanols are a type of chemical compound known as alcohols, specifically they are fatty alcohols with a chain of 8 carbon atoms. The most common octanol is called 1-octanol, which has the chemical formula CH3(CH2)7OH. It is a colorless oily liquid that is used in the synthesis of other chemicals and as a solvent. Octanols are often used as standards for measuring the partition coefficient between octanol and water, which is a measure of a compound's hydrophobicity or lipophilicity. This property is important in understanding how a compound may be absorbed, distributed, metabolized, and excreted in the body.

Immunohistochemistry (IHC) is a technique used in pathology and laboratory medicine to identify specific proteins or antigens in tissue sections. It combines the principles of immunology and histology to detect the presence and location of these target molecules within cells and tissues. This technique utilizes antibodies that are specific to the protein or antigen of interest, which are then tagged with a detection system such as a chromogen or fluorophore. The stained tissue sections can be examined under a microscope, allowing for the visualization and analysis of the distribution and expression patterns of the target molecule in the context of the tissue architecture. Immunohistochemistry is widely used in diagnostic pathology to help identify various diseases, including cancer, infectious diseases, and immune-mediated disorders.

Alzheimer's disease is a progressive disorder that causes brain cells to waste away (degenerate) and die. It's the most common cause of dementia — a continuous decline in thinking, behavioral and social skills that disrupts a person's ability to function independently.

The early signs of the disease include forgetting recent events or conversations. As the disease progresses, a person with Alzheimer's disease will develop severe memory impairment and lose the ability to carry out everyday tasks.

Currently, there's no cure for Alzheimer's disease. However, treatments can temporarily slow the worsening of dementia symptoms and improve quality of life.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

A "knockout" mouse is a genetically engineered mouse in which one or more genes have been deleted or "knocked out" using molecular biology techniques. This allows researchers to study the function of specific genes and their role in various biological processes, as well as potential associations with human diseases. The mice are generated by introducing targeted DNA modifications into embryonic stem cells, which are then used to create a live animal. Knockout mice have been widely used in biomedical research to investigate gene function, disease mechanisms, and potential therapeutic targets.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Brain mapping is a broad term that refers to the techniques used to understand the structure and function of the brain. It involves creating maps of the various cognitive, emotional, and behavioral processes in the brain by correlating these processes with physical locations or activities within the nervous system. Brain mapping can be accomplished through a variety of methods, including functional magnetic resonance imaging (fMRI), positron emission tomography (PET) scans, electroencephalography (EEG), and others. These techniques allow researchers to observe which areas of the brain are active during different tasks or thoughts, helping to shed light on how the brain processes information and contributes to our experiences and behaviors. Brain mapping is an important area of research in neuroscience, with potential applications in the diagnosis and treatment of neurological and psychiatric disorders.

Cerebrospinal fluid (CSF) is a clear, colorless fluid that surrounds and protects the brain and spinal cord. It acts as a shock absorber for the central nervous system and provides nutrients to the brain while removing waste products. CSF is produced by specialized cells called ependymal cells in the choroid plexus of the ventricles (fluid-filled spaces) inside the brain. From there, it circulates through the ventricular system and around the outside of the brain and spinal cord before being absorbed back into the bloodstream. CSF analysis is an important diagnostic tool for various neurological conditions, including infections, inflammation, and cancer.

Middle Cerebral Artery (MCA) infarction is a type of ischemic stroke that occurs when there is an obstruction in the blood supply to the middle cerebral artery, which is one of the major blood vessels that supplies oxygenated blood to the brain. The MCA supplies blood to a large portion of the brain, including the motor and sensory cortex, parts of the temporal and parietal lobes, and the basal ganglia.

An infarction is the death of tissue due to the lack of blood supply, which can lead to damage or loss of function in the affected areas of the brain. Symptoms of MCA infarction may include weakness or numbness on one side of the body, difficulty speaking or understanding speech, vision problems, and altered levels of consciousness.

MCA infarctions can be caused by various factors, including embolism (a blood clot that travels to the brain from another part of the body), thrombosis (a blood clot that forms in the MCA itself), or stenosis (narrowing of the artery due to atherosclerosis or other conditions). Treatment for MCA infarction may include medications to dissolve blood clots, surgery to remove the obstruction, or rehabilitation to help regain lost function.

The brainstem is the lower part of the brain that connects to the spinal cord. It consists of the midbrain, pons, and medulla oblongata. The brainstem controls many vital functions such as heart rate, breathing, and blood pressure. It also serves as a relay center for sensory and motor information between the cerebral cortex and the rest of the body. Additionally, several cranial nerves originate from the brainstem, including those that control eye movements, facial movements, and hearing.

Biological transport refers to the movement of molecules, ions, or solutes across biological membranes or through cells in living organisms. This process is essential for maintaining homeostasis, regulating cellular functions, and enabling communication between cells. There are two main types of biological transport: passive transport and active transport.

Passive transport does not require the input of energy and includes:

1. Diffusion: The random movement of molecules from an area of high concentration to an area of low concentration until equilibrium is reached.
2. Osmosis: The diffusion of solvent molecules (usually water) across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
3. Facilitated diffusion: The assisted passage of polar or charged substances through protein channels or carriers in the cell membrane, which increases the rate of diffusion without consuming energy.

Active transport requires the input of energy (in the form of ATP) and includes:

1. Primary active transport: The direct use of ATP to move molecules against their concentration gradient, often driven by specific transport proteins called pumps.
2. Secondary active transport: The coupling of the movement of one substance down its electrochemical gradient with the uphill transport of another substance, mediated by a shared transport protein. This process is also known as co-transport or counter-transport.

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.

Medical Definition:

Matrix metalloproteinase 9 (MMP-9), also known as gelatinase B or 92 kDa type IV collagenase, is a member of the matrix metalloproteinase family. These enzymes are involved in degrading and remodeling the extracellular matrix (ECM) components, playing crucial roles in various physiological and pathological processes such as wound healing, tissue repair, and tumor metastasis.

MMP-9 is secreted as an inactive zymogen and activated upon removal of its propeptide domain. It can degrade several ECM proteins, including type IV collagen, elastin, fibronectin, and gelatin. MMP-9 has been implicated in numerous diseases, such as cancer, rheumatoid arthritis, neurological disorders, and cardiovascular diseases. Its expression is regulated at the transcriptional, translational, and post-translational levels, and its activity can be controlled by endogenous inhibitors called tissue inhibitors of metalloproteinases (TIMPs).

The blood-retinal barrier (BRB) is a specialized physiological barrier in the eye that helps regulate the movement of molecules between the retina and the bloodstream. It is made up of tight junctions between the endothelial cells of retinal blood vessels and between the pigment epithelium cells of the retina, which restrict the paracellular diffusion of solutes.

The BRB plays a crucial role in maintaining the health and function of the retina by preventing harmful substances from entering the retina while allowing essential nutrients and oxygen to reach the retinal tissues. Disruption of the BRB has been implicated in various retinal diseases, including diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion.

A brain abscess is a localized collection of pus in the brain that is caused by an infection. It can develop as a result of a bacterial, fungal, or parasitic infection that spreads to the brain from another part of the body or from an infection that starts in the brain itself (such as from a head injury or surgery).

The symptoms of a brain abscess may include headache, fever, confusion, seizures, weakness or numbness on one side of the body, and changes in vision, speech, or behavior. Treatment typically involves antibiotics to treat the infection, as well as surgical drainage of the abscess to relieve pressure on the brain.

It is a serious medical condition that requires prompt diagnosis and treatment to prevent potentially life-threatening complications such as brain herniation or permanent neurological damage.

I am not aware of a widely recognized or established medical term called "Blood-Air Barrier." It is possible that you may be referring to a concept or phenomenon that goes by a different name, or it could be a term that is specific to certain context or field within medicine.

In general, the terms "blood" and "air" refer to two distinct and separate compartments in the body, and there are various physiological barriers that prevent them from mixing with each other under normal circumstances. For example, the alveolar-capillary membrane in the lungs serves as a barrier that allows for the exchange of oxygen and carbon dioxide between the air in the alveoli and the blood in the capillaries, while preventing the two from mixing together.

If you could provide more context or clarify what you mean by "Blood-Air Barrier," I may be able to provide a more specific answer.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

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.

Transgenic mice are genetically modified rodents that have incorporated foreign DNA (exogenous DNA) into their own genome. This is typically done through the use of recombinant DNA technology, where a specific gene or genetic sequence of interest is isolated and then introduced into the mouse embryo. The resulting transgenic mice can then express the protein encoded by the foreign gene, allowing researchers to study its function in a living organism.

The process of creating transgenic mice usually involves microinjecting the exogenous DNA into the pronucleus of a fertilized egg, which is then implanted into a surrogate mother. The offspring that result from this procedure are screened for the presence of the foreign DNA, and those that carry the desired genetic modification are used to establish a transgenic mouse line.

Transgenic mice have been widely used in biomedical research to model human diseases, study gene function, and test new therapies. They provide a valuable tool for understanding complex biological processes and developing new treatments for a variety of medical conditions.

The endothelium is a thin layer of simple squamous epithelial cells that lines the interior surface of blood vessels, lymphatic vessels, and heart chambers. The vascular endothelium, specifically, refers to the endothelial cells that line the blood vessels. These cells play a crucial role in maintaining vascular homeostasis by regulating vasomotor tone, coagulation, platelet activation, inflammation, and permeability of the vessel wall. They also contribute to the growth and repair of the vascular system and are involved in various pathological processes such as atherosclerosis, hypertension, and diabetes.

The Blood-Testis Barrier (BTB) is a unique structural and functional feature of the seminiferous epithelium in the testes, which forms a tight junction between adjacent Sertoli cells in the semi-niferous tubules. This barrier selectively restricts the passage of molecules, including potentially harmful substances and immune cells, from the systemic circulation into the adluminal compartment of the seminiferous epithelium where spermatogenesis occurs. This helps to maintain a immunologically privileged microenvironment that is essential for the survival and maturation of developing sperm cells, preventing an immune response against them. The BTB also regulates the movement of molecules required for spermatogenesis, such as nutrients, hormones, and signaling molecules, from the basal compartment to the adluminal compartment.

Communication barriers in a medical context refer to any factors that prevent or hinder the effective exchange of information between healthcare providers and patients, or among healthcare professionals themselves. These barriers can lead to misunderstandings, errors, and poor patient outcomes. Common communication barriers include:

1. Language differences: When patients and healthcare providers do not speak the same language, it can lead to miscommunication and errors in diagnosis and treatment.
2. Cultural differences: Cultural beliefs and values can affect how patients perceive and communicate their symptoms and concerns, as well as how healthcare providers deliver care.
3. Literacy levels: Low health literacy can make it difficult for patients to understand medical information, follow treatment plans, and make informed decisions about their care.
4. Disability: Patients with hearing or vision impairments, speech disorders, or cognitive impairments may face unique communication challenges that require accommodations and specialized communication strategies.
5. Emotional factors: Patients who are anxious, stressed, or in pain may have difficulty communicating effectively, and healthcare providers may be less likely to listen actively or ask open-ended questions.
6. Power dynamics: Hierarchical relationships between healthcare providers and patients can create power imbalances that discourage patients from speaking up or asking questions.
7. Noise and distractions: Environmental factors such as noise, interruptions, and distractions can make it difficult for patients and healthcare providers to hear, focus, and communicate effectively.

Effective communication is critical in healthcare settings, and addressing communication barriers requires a multifaceted approach that includes training for healthcare providers, language services for limited English proficient patients, and accommodations for patients with disabilities.

Blood-ocular barrier - Physical barrier between the local blood vessels and most parts of the eye itself Blood-retinal barrier ... The blood-brain barrier is formed by the brain capillary endothelium and excludes from the brain 100% of large-molecule ... The border zones between brain tissue "behind" the blood-brain barrier and zones "open" to blood signals in certain CVOs ... thus protecting the brain from harmful or unwanted substances in the blood. The blood-brain barrier is formed by endothelial ...
To treat brain tumours and other brain related diseases, blood-brain barrier disruption is needed for the anti-cancer drugs to ... The blood-brain barrier (BBB) is protected by a network of blood vessels and tissue that shields it from harmful substances. ... Blood-brain barrier disruption is the surgical process whereby drugs are used to create openings between cells in the blood- ... Studies have shown that blood-brain barrier disruption can cause diseases in the central nervous system. "Definition of blood- ...
Hladky, S. B., & Barrand, M. A. (2016). Fluid and ion transfer across the blood-brain and blood-cerebrospinal fluid barriers; a ... Pardridge W. M. (2012). Drug transport across the blood-brain barrier. Journal of cerebral blood flow and metabolism : official ... Brain Res 1989;482:57-66. Cohen DM, Patel CB, Ahobila-Vajjula P, et al. Blood-spinal cord barrier permeability in experimental ... The anatomy of the BSCB is very similar to the anatomy of the blood-brain barrier (BBB); however many key differences exist ...
the blood-brain barrier. Though there are many morphological features conserved among caveolae, the functions of each CAV ... The importance of them for the clearance of LDL from blood was discovered by Richard G. Anderson, Michael S. Brown and Joseph L ... which removes LDL from circulating blood), the transferrin receptor (which brings ferric ions bound by transferrin into the ...
Francesca, B.; Rezzani, R. (2010). "Aquaporin and Blood Brain Barrier". Current Neuropharmacology. 8 (2): 92-96. doi:10.2174/ ... 1988). "The Colton blood group locus. A linkage analysis". Transfusion. 28 (5): 435-8. doi:10.1046/j.1537-2995.1988.28588337331 ... Additionally, it is found in red blood cells, vascular endothelium, the gastrointestinal tract, sweat glands, lungs, and the ... "Entrez Gene: AQP1 aquaporin 1 (Colton blood group)". Knepper MA (July 1994). "The aquaporin family of molecular water channels ...
Davson, Hugh (1989), "History of the Blood-Brain Barrier Concept", Implications of the Blood-Brain Barrier and its Manipulation ... The blood-brain barrier refers to a diffusion barrier formed by the endothelial walls of the blood vessels and capillaries in ... She is best known for her pioneering work on the blood-brain barrier, which she described as hemato-encephalic barrier in 1921 ... blood-brain barrier both selectively allows certain substances to enter the brain and protects the internal milieu of the brain ...
Smith, Quentin R. (April 2000). "Transport of glutamate and other amino acids at the blood-brain barrier". The Journal of ... Hawkins, Richard A. (September 2009). "The blood-brain barrier and glutamate". The American Journal of Clinical Nutrition. 90 ( ... Glutamate does not easily pass the blood brain barrier, but, instead, is transported by a high-affinity transport system. It ... Malignant brain tumors known as glioma or glioblastoma exploit this phenomenon by using glutamate as an energy source, ...
Failure of the blood-brain barrier may also be a causal mechanism as it would allow substances in the blood to enter the brain ... Oby E, Janigro D (November 2006). "The blood-brain barrier and epilepsy". Epilepsia. 47 (11): 1761-74. doi:10.1111/j.1528- ... This may be partly done by imaging the brain and performing blood tests. Epilepsy can often be confirmed with an EEG, but a ... Mild brain injury increases the risk about two-fold while severe brain injury increases the risk seven-fold. In those who have ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2003). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ...
Fiori A, Cardelli P, Negri L, Savi MR, Strom R, Erspamer V (August 1997). "Deltorphin transport across the blood-brain barrier ... May 1997). "Structure-activity relationships of a series of [D-Ala2]deltorphin I and II analogues; in vitro blood-brain barrier ... and on account of its unusually high blood-brain-barrier penetration rate, produces centrally-mediated analgesic effects in ...
When the blood-brain barrier has been compromised, albumin-bound Evans blue enters the CNS. Evans blue is pharmacologically ... Evans blue is also used to assess the permeability of the blood-brain barrier to macromolecules. Because serum albumin cannot ... Hawkins BT, Egleton RD (2006). "Fluorescence imaging of blood-brain barrier disruption". Journal of Neuroscience Methods. 151 ( ... Because of this, it can be useful in physiology in estimating the proportion of body water contained in blood plasma. It ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2003). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2003). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ...
"Biousian glycopeptides penetrate the blood-brain barrier". Tetrahedron: Asymmetry. Carbohydrate Science. Part 1. 16 (1): 65-75 ... October 2000). "Improved bioavailability to the brain of glycosylated Met-enkephalin analogs". Brain Research. 881 (1): 37-46. ...
2009 Oct 23;105(9):860-8. What is the blood-brain barrier (not)? Bechmann I, Galea I, Perry VH. Trends Immunol. 2007 Jan;28(1): ... Vascular recruitment in the brain is thought to lead to new capillaries and increase the cerebral blood flow. The existence of ... That insulin can act in this way has been proposed based on increases in limb blood flow and skeletal muscle blood volume which ... Evidence that heterogeneity of cerebral blood flow does not involve vascular recruitment. Williams JL, Shea M, Jones SC. Am J ...
Minagar A, Alexander JS (December 2003). "Blood-brain barrier disruption in multiple sclerosis". Mult Scler. 9 (6): 540-9. doi: ... "Spots" can occur as a result of changes in brain water content.: 113 Evoked potential is an electrical potential recorded from ... and other diseases affecting the brain. It has also been used to study the metabolism of other organs such as muscles.: 309 ... Brain Sci. 3 (4): 1282-324. doi:10.3390/brainsci3031282. PMC 4061877. PMID 24961530. Hochmeister S, Romauch M, Bauer J, Seifert ...
It is expressed primarily in the blood-brain barrier and liver and is thought to be involved in protecting cells from toxins. ... "Challenges for blood-brain barrier (BBB) screening". Xenobiotica. 37 (10-11): 1135-51. doi:10.1080/00498250701570285. PMID ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2003). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ... and tissue-barrier function. It forms anion-selective paracellular channels and is localized mainly in kidney proximal tubules ... Tissue Barriers. 9 (1): 1848212. doi:10.1080/21688370.2020.1848212. PMC 7849786. PMID 33300427. Krug SM, Günzel D, Conrad MP, ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Sticky cells, blood vessels and cancer - the paradox of Claudin-14 - Marianne Baker, Cancer Research UK Science Update blog, 14 ... Tight junctions form continuous seals around cells and serve as a physical barrier to prevent solutes and water from passing ... There are also suggestions that CLDN14 plays a role in tumour angiogenesis (blood vessel formation), as deletion of a single ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... "Paracellular tightness and claudin-5 expression is increased in the BCEC/astrocyte blood-brain barrier model by increasing ... Tight junction strands serve as a physical barrier to prevent solutes and water from passing freely through the paracellular ... Tsukita S, Furuse M (2002). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ...
... s have an unusually high blood-brain barrier penetration rate. The nonselective opiate antagonist naloxone inhibits ... "Deltorphin transport across the blood-brain barrier". Proceedings of the National Academy of Sciences of the United States of ... deltorphin uptake by brain microvessels, but neither the selective δ-opioid antagonist naltrindole nor a number of opioid ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2003). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ...
Poor penetration through the blood-brain barrier. Because of numerous adverse effect and limitations in use, new drugs with ... Some were found to have effect on lower blood sugar levels and others act as hemostatics. The most interesting thing was that ... A high number of white cells in the blood indicates leukemia, so a new anti-cancer drug had been discovered. These two ... It is known that some compounds can inhibit the formation of new blood vessels (inhibit the process of angiogenesis) or shut ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2003). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ... "A claudin-9-based ion permeability barrier is essential for hearing". PLOS Genetics. 5 (8): e1000610. doi:10.1371/journal.pgen. ...
Over the last decade, S100B has emerged as a candidate peripheral biomarker of blood-brain barrier (BBB) permeability and CNS ... Marchi N, Cavaglia M, Fazio V, Bhudia S, Hallene K, Janigro D (April 2004). "Peripheral markers of blood-brain barrier damage ... Czeisler BM, Janigro D (June 2006). "Reading and writing the blood-brain barrier: relevance to therapeutics". Recent Patents on ... "Seizure-promoting effect of blood-brain barrier disruption". Epilepsia. 48 (4): 732-42. doi:10.1111/j.1528-1167.2007.00988.x. ...
Geldenhuys WJ, Mohammad AS, Adkins CE, Lockman PR (2015). "Molecular determinants of blood-brain barrier permeation". ... "Selective expression of the large neutral amino acid transporter at the blood-brain barrier". Proceedings of the National ...
It is thought that HIV uses a "Trojan horse" mechanism to enter the brain. Normally, the blood-brain barrier (BBB) serves as a ... Berger JR, Avison M (September 2004). "The blood brain barrier in HIV infection". Frontiers in Bioscience. 9 (1-3): 2680-5. doi ... further compromising the blood-brain barrier. The toxicity spreads through a gap junction-dependent mechanism. HIV is ... "Human immunodeficiency virus infection of human astrocytes disrupts blood-brain barrier integrity by a gap junction-dependent ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2002). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ... forming continuous seals around cells and serving as a physical barrier to prevent solutes and water from passing freely ...
Kniesel U, Wolburg H (2000). "Tight junctions of the blood-brain barrier". Cell. Mol. Neurobiol. 20 (1): 57-76. doi:10.1023/A: ... Tsukita S, Furuse M (2003). "Claudin-based barrier in simple and stratified cellular sheets". Curr. Opin. Cell Biol. 14 (5): ...
... some nanoparticles are able to bypass the Blood Brain Barrier to deliver therapeutic drugs to the brain. Nanoparticles have ... Zhou, Yiqun; Peng, Zhili; Seven, Elif S.; Leblanc, Roger M. (2018-01-28). "Crossing the blood-brain barrier with nanoparticles ... They could play an important role in blood vessel cleanup. Theoretically, nanotubes with SHP1i molecules attached to them would ... signal macrophages to clean up plaque in blood vessels without destroying any healthy tissue. Researchers have tested this type ...
Blood-ocular barrier - Physical barrier between the local blood vessels and most parts of the eye itself Blood-retinal barrier ... The blood-brain barrier is formed by the brain capillary endothelium and excludes from the brain 100% of large-molecule ... The border zones between brain tissue "behind" the blood-brain barrier and zones "open" to blood signals in certain CVOs ... thus protecting the brain from harmful or unwanted substances in the blood. The blood-brain barrier is formed by endothelial ...
... present in brain capillaries, constitutes an essential barrier mechanism for normal functioning and development of the brain ... present in brain capillaries, constitutes an essential barrier mechanism for normal functioning and development of the brain ... The Blood Brain Barrier. The term blood-brain barrier (BBB) was used to describe the unique characteristics of the ... Lee, N. Y., and Kang, Y. S. (2004). The brain-to-blood efflux transport of taurine and changes in the blood-brain barrier ...
... brain tissue damage can occur before lesions even appear on imaging. ... MRI brain scans may be too late to identify the beginning stages of brain damage caused by a leaky blood-brain barrier in ... we wanted to see if a leaky blood-brain barrier was linked to degeneration of brain tissue even before these brain lesions ... Leaky Blood-Brain Barrier Causes Brain Damage Before MRI Catches Lesions. March 24, 2021. Whitney J. Palmer ...
... is that the ongoing clearance of bad cells and waste is a result of the evolutionary elegant design of the blood-brain barrier ...
What is the Blood-Brain Barrier?. The blood-brain barrier prevents toxins and microorganisms from crossing from the blood ... After a disruption in the blood-brain barrier, such as brain hemorrhage or edema, curcumin appears to help restore blood-brain ... The Blood-Brain Barrier. This is the 4th article in our series on the brain, memory, and dementia. This article discusses the ... Brain Res. 1594:245-55. ↩. * Yuan J, Liu W, Zhu H, Zhang X, Feng Y, et al. (2017). Curcumin attenuates blood-brain barrier ...
Despite our growing understanding of the critical mechanistic events in post-stroke brain in ... Keywords: Cell penetrating peptide, TAT protein transduction domains, blood brain barrier, stroke, neuroprotection, brain cells ... Keywords: Cell penetrating peptide, TAT protein transduction domains, blood brain barrier, stroke, neuroprotection, brain cells ... Delivery of Neurotherapeutics Across the Blood Brain Barrier in Stroke. Author(s): Xiaoming Hu, Meijuan Zhang, Rehana K Leak, ...
A new painkiller nanomedicine to bypass the blood-brain barrier and the use of morphine.. ... A new painkiller nanomedicine to bypass the blood-brain barrier and the use of morphine. ... A new painkiller nanomedicine to bypass the blood-brain barrier and the use of morphine. ...
The Blood Brain Barrier Lab Support BGU Support The Blood Brain Barrier Lab ... Imaging blood-brain barrier dysfunction in football players.. Imaging blood-brain barrier dysfunction as a biomarker for ... Mechanisms of neuronal activity-induced modulation of the blood-brain barrier. *Mechanisms of transport across the blood-brain ... Mechanisms of neuronal activity-induced modulation of the blood-brain barrier. *Mechanisms of transport across the blood-brain ...
Radiofrequency and Extremely Low-Frequency Electromagnetic Field Effects on the Blood-Brain Barrier. Radiofrequency and ... Radiofrequency and Extremely Low-Frequency Electromagnetic Field Effects on the Blood-Brain Barrier ... http://omega.twoday.net/search?q=blood+brain+barrier. http://omega.twoday.net/search?q=Lars+Malmgren ... Extremely Low-Frequency Electromagnetic Field Effects on the Blood-Brain Barrier - Upload a Document to Scribd ...
Here we show that changes in blood-brain barrier transport and/or proteolysis were largely responsible for the age-related ... The magnitude of CSF-based clearance was also lower than that due to blood-brain barrier function plus proteolysis. These ... Importance of CSF-based Aβ clearance with age in humans increases with declining efficacy of blood-brain barrier/proteolytic ... results suggest important roles for blood-brain barrier transport and proteolytic degradation of Aβ in the development ...
... barrier is adapted via TGF-βsignaling-dependent transcriptional regulation of carbohydrate transporters to protect the brain ... Detailed analysis of transporter expression and glucose uptake rates shows that carbohydrate import at the blood-brain ... 2014) Barrier mechanisms in the Drosophila blood-brain barrier Frontiers in Neuroscience 8:414. ... 2006) The rat blood-brain barrier transcriptome Journal of Cerebral Blood Flow & Metabolism 26:959-973. ...
Divalent metal transporter 1 (DMT1) in the brain: implications for a role in iron transport at the blood-brain barrier, and ... Divalent metal transporter 1 (DMT1) in the brain: implications for a role in iron transport at the blood-brain barrier, and ... Divalent metal transporter 1 (DMT1) in the brain : implications for a role in iron transport at the blood-brain barrier, and ... Divalent metal transporter 1 (DMT1) in the brain: implications for a role in iron transport at the blood-brain barrier, and ...
... are building paracellular barriers which protect the tissue from the external and internal... ... In Vitro Blood Brain Barrier Model Paracellular Barriers Blood-brain Barrier (BBB) Astrocyte End-feet Pericytes Basal Membrane ... Brain Parenchyma In Vitro BBB Models Bovine Brain Tissue Porcine Brain Tissue Rat Brain Tissue Mouse Brain Tissue Primary Cell ... Weksler, B. B. Blood-brain barrier-specific properties of a human adult brain endothelial cell line. FASEB. J. 19, 1872 (2005). ...
... we characterized blood-brain barrier (BBB) function and neurovascular coupling (NVC) at the level of individual brain vessels ... we characterized blood-brain barrier (BBB) function and neurovascular coupling (NVC) at the level of individual brain vessels ... we characterized blood-brain barrier (BBB) function and neurovascular coupling (NVC) at the level of individual brain vessels ... Preserved blood-brain barrier and neurovascular coupling in female 5xFAD model of Alzheimers disease. *Mark ...
This work describes a noninvasive method to safely enable drug delivery to brain tumors and other CNS diseases, addressing a ... The blood-brain barrier (BBB) prevents entry of most drugs into the brain and is a major hurdle to the use of drugs for brain ... Noninvasive localized delivery of Herceptin to the mouse brain by MRI-guided focused ultrasound-induced blood-brain barrier ... because they are blocked by the blood-brain barrier (BBB). This barrier restricts the passage of substances except for small, ...
Clinical Trial to Disrupt the Blood-brain Barrier for Brain Tumor Treatment Launched at University of Maryland Published: 23 ... Radiology Business , Historic Clinical Trial to Focus on Use of MRI-guided Focused Ultrasound to Open Blood-brain Barrier 8/10/ ... Researchers are investigating the use of focused ultrasound to disrupt the blood-brain barrier (BBB) in patients who are ... Medical Xpress , First FDA-approved Study of Focused Ultrasound to Open Blood-brain Barrier 8/9/18 ...
... luminal side of the blood-brain barrier and detaching from transferrin receptor on the brain side of the blood-brain barrier. ... Transferrin receptor is a well-characterized receptor on the blood-brain barrier that is accessible from the blood and known to ... the brain may be able to deliver therapeutic molecules to the brain that otherwise would be excluded by the blood-brain barrier ... Nanoparticle Transferrin Blood Brain Barrier Receptor Mediated Transcytosis. Degree Grantor:. California Institute of ...
Evaluation of a Human Neurovascular Model to Complement a Parallel Non-human Primate Selection for Blood-Brain Barrier ...
Bacteria can bypass the blood-brain barrier (BBB) transcellularly, paracellularly and/or in infected phagocytes, suggesting the ... Emerging blood-brain-barrier-crossing nanotechnology for brain cancer theranostics. Chem. Soc. Rev. 48, 2967-3014 (2019). ... Brain bioavailability of human intravenous immunoglobulin and its transport through the murine blood- brain barrier. J. Cereb. ... a new strategy to traverse blood-brain barrier for imaging and therapy of brain tumors. Adv. Funct. Mater. 30,1909369 (2020). ...
... we discuss in depth the crucial blood brain barrier and how you can support. ... In our second of our 4-part series on the importance of barriers in the body, ... In our second of our 4-part series on the importance of barriers in the body, we discuss in depth the crucial blood brain ... and how taking simple steps to protect the blood brain barrier may help. ...
However, the blood-brain barrier (BBB) restricts Rg1 in reaching the CNS. In this study, we investigated the therapeutic ... Ginsenoside Rg1 nanoparticle penetrating the blood-brain barrier to improve the cerebral function of diabetic rats complicated ... Ginsenoside Rg1 nanoparticle penetrating the blood-brain barrier to improve the cerebral function of diabetic rats complicated ... PHRO could penetrate the BBB with high concentration in brain tissue to reduce the cerebral infarction volume and promote ...
... including this cortical subarachnoid blood, elevated transcranial Doppler velocities and now blood-brain barrier breakdown on ... Cite this: Blood-Brain Barrier Breakdown Common in RCVS - Medscape - Nov 20, 2017. ... SCOTTSDALE, Arizona - Distinctive signs of breakdown of the blood-brain barrier (BBB) are commonly evident in patients with ... contrast-enhanced flare sequencing imaging showed this remarkable breakdown of the blood-brain barrier, indicating that there ...
Ireland Early Career Blood-Brain Barrier Symposium series provides an opportunity for early career researchers to present their ... 2013 by UK & Ireland Early Career Blood-Brain Barrier Symposium. Website created by David Dickens. ... Ireland Early Career Blood-Brain Barrier (BBB) Society will take place virtually on the 23rd of November. ... This symposium provides an opportunity for ECRs to present their research on the barriers of the CNS in the form of 10 online ...
Abstract The blood-brain barrier (BBB) is a complex organization of cerebral endothelial cells (CEC), pericytes and their basal ... Role of the blood-brain barrier in multiple sclerosis.. Ortiz GG, Pacheco-Moisés FP, Macías-Islas MÁ, Flores-Alvarado LJ, ... Blood-brain Barrier Disruption in Multiple Sclerosis. Alireza Minagar 1, J Steven AlexanderAffiliations *PMID: 14664465 ... The blood-brain barrier (BBB) is a complex organization of cerebral endothelial cells (CEC), pericytes and their basal lamina, ...
The results obtained by the Center for Brain Research in Vienna show that the development of this inflammatory disease is ... for multiple sclerosis has prompted an international research group to investigate how immune cells can cross the blood-brain ... barrier and trigger inflammatory processes in nerve tissue. ... "blood-brain barrier" normally prevents white blood cells and ... Our brain is using up an extreme amount of energy and it is richly perfused with blood vessels. The blood-brain barrier ...
... researchers develop a blood-brain-barrier-on-chip. ... Simulating the brains protective barrier in a controllable lab ... "Due to the distinctive characteristics of the blood-brain barrier, delivering drugs to the brain proves particularly ... The blood-brain barrier (BBB), a natural safeguard and a formidable obstacle, has long been a double-edged sword for doctors ... New technique could unlock secrets of blood-brain barrier March 02, 2023 ...
The blood-brain barrier is the blood vessels that vascularize the central nervous system (CNS). This barrier tightly regulates ... The blood-brain barrier is the blood vessels that vascularize the central nervous system (CNS). This barrier tightly regulates ... and cells between the blood and the brain. The BBB allows necess ... and cells between the blood and the brain. The BBB allows ... The blood-brain barrier is the blood vessels that vascularize the central nervous system (CNS). This barrier tightly regulates ...
Home › Nanobodies to Cross the Blood Brain Barrier ...
Get editable icons and illustrations of Blood brain barrier (with astrocytes) 2. Create professional science figures in minutes ... blood brain barrier ... Blood brain barrier (with astrocytes) 2. Blood brain barrier ( ...
Jones, Hayley Antiepileptic drug transport at the blood-brain barrier, the role of the SLC transporter family. PhD thesis, ... Antiepileptic drug transport at the blood-brain barrier, the role of the SLC transporter family ... Antiepileptic drug transport at the blood-brain barrier, the role of the SLC transporter family ... this thesis was to investigate and identify SLC transporter systems of interest that are expressed at the blood-brain barrier ( ...
  • The blood-brain barrier is formed by endothelial cells of the capillary wall, astrocyte end-feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane. (wikipedia.org)
  • Circumventricular organs (CVOs) are individual structures located adjacent to the fourth ventricle or third ventricle in the brain, and are characterized by dense capillary beds with permeable endothelial cells unlike those of the blood-brain barrier. (wikipedia.org)
  • As observed by electron microscopy, 1-day acute stress induced morphological changes indicating damage in capillary endothelial cells in both brain regions. (sigmaaldrich.com)
  • The study shows that in as many as 70% of patients classified as having RCVS, contrast-enhanced flare sequencing imaging showed this remarkable breakdown of the blood-brain barrier, indicating that there is activity at the capillary level and it often is present even in the absence of initial vasoconstriction," said presenter David W. Dodick, MD, professor of neurology at the Mayo Clinic in Scottsdale. (medscape.com)
  • His group showed that disrupted cross-talk between BBB-associated pericytes and brain capillary endothelial cells within the neurovascular unit leads to neuronal dysfunction in both synapses and neurons. (usc.edu)
  • At 4 h after MWCNT exposure, broad disruption of the blood-brain barrier (BBB) was observed across the capillary bed with the small molecule fluorescein, concomitant with reactive astrocytosis. (cdc.gov)
  • in this situation, factors influencing permeability of the blood-brain barrier (eg, acidosis, infection) and the amount of unbound (versus albumin-bound) bilirubin may play a role. (medscape.com)
  • Physiologic and anatomic evidence suggest that 5-hydroxytryptamine (5-HT) neurons regulate local cerebral blood flow and blood-brain barrier permeability. (diigo.com)
  • The position of these Na + -independent transporters ensures AA availability in the brain and also its bidirectional transport across the endothelial cells. (frontiersin.org)
  • The majority of these active transporters are present exclusively at the abluminal membrane and are responsible for AA efflux from the brain into the endothelial cells. (frontiersin.org)
  • Once inside the cell, the facilitative transporters located in the luminal membranes mediate export from the endothelial cell to the blood. (frontiersin.org)
  • The blood-brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that regulates the transfer of solutes and chemicals between the circulatory system and the central nervous system, thus protecting the brain from harmful or unwanted substances in the blood. (wikipedia.org)
  • The BBB results from the selectivity of the tight junctions between the endothelial cells of brain capillaries, restricting the passage of solutes. (wikipedia.org)
  • The BBB is composed of endothelial cells restricting passage of substances from the blood more selectively than endothelial cells of capillaries elsewhere in the body. (wikipedia.org)
  • Measurement of brain uptake of various blood-borne solutes showed that newborn endothelial cells were functionally similar to those in adults, indicating that a selective BBB is operative at birth. (wikipedia.org)
  • Frontal cortex and hippocampus sections were immunostained for markers of brain endothelial cells (claudin-5, occluding, and glucose transporter-1) and astroglia (GFAP). (sigmaaldrich.com)
  • Morphological changes and intensity alterations in brain endothelial tight junction proteins claudin-5 and occludin were induced by stress. (sigmaaldrich.com)
  • Following restraint stress significant increases in the fluorescence intensity of glucose transporter-1 were detected in brain endothelial cells in the frontal cortex and hippocampus. (sigmaaldrich.com)
  • These findings indicate that stress exerts time-dependent changes in the staining pattern of tight junction proteins occludin, claudin-5, and glucose transporter-1 at the level of brain capillaries and in the ultrastructure of brain endothelial cells and astroglial endfeet, which may contribute to neurodegenerative processes, cognitive and behavioral dysfunctions. (sigmaaldrich.com)
  • Endothelial cells build up the vessel wall and control the exchange between the blood and surrounding brain tissue. (lu.se)
  • The blood-brain-barrier (BBB), present in brain capillaries, constitutes an essential barrier mechanism for normal functioning and development of the brain. (frontiersin.org)
  • Specialized brain structures participating in sensory and secretory integration within brain neural circuits-the circumventricular organs and choroid plexus-have in contrast highly permeable capillaries. (wikipedia.org)
  • Permeable capillaries of the sensory CVOs (area postrema, subfornical organ, vascular organ of the lamina terminalis) enable rapid detection of circulating signals in systemic blood, while those of the secretory CVOs (median eminence, pineal gland, pituitary lobes) facilitate transport of brain-derived signals into the circulating blood. (wikipedia.org)
  • Consequently, the CVO permeable capillaries are the point of bidirectional blood-brain communication for neuroendocrine function. (wikipedia.org)
  • The ultrastructure of brain capillaries was investigated by electron microscopy. (sigmaaldrich.com)
  • Not all vessels in the human brain exhibit BBB properties. (wikipedia.org)
  • INTRODUCTION: Dysfunction of the cerebral vasculature is considered one of the key components of Alzheimer's disease (AD), but the mechanisms affecting individual brain vessels are poorly understood. (lu.se)
  • METHODS: Here, using in vivo two-photon microscopy in superficial cortical layers and ex vivo imaging across brain regions, we characterized blood-brain barrier (BBB) function and neurovascular coupling (NVC) at the level of individual brain vessels in adult female 5xFAD mice, an aggressive amyloid-β (Aβ) model of AD. (lu.se)
  • At the interface between blood vessels and nerve tissue, the "blood-brain barrier" normally prevents white blood cells and proteins from passing through. (fwf.ac.at)
  • Our brain is using up an extreme amount of energy and it is richly perfused with blood vessels. (fwf.ac.at)
  • This barrier is formed by the walls of the blood vessels in the brain and spinal cord that are less permeable there than they are in other organs. (fwf.ac.at)
  • Restraint Stress-Induced Morphological Changes at the Blood-Brain Barrier in Adult Rats. (sigmaaldrich.com)
  • In the present study the effects of restraint stress with different duration (1, 3, and 21 days) were investigated on the morphology of the blood-brain barrier in male adult Wistar rats. (sigmaaldrich.com)
  • Researchers from Chang Gung University in Taiwan have now managed to shrink tumors deep inside the brains of rats by using this technique to blast drugs in through tiny channels created within the vasculature. (extremetech.com)
  • PHRO could penetrate the BBB with high concentration in brain tissue to reduce the cerebral infarction volume and promote neuronal recovery in vivo. (altmetric.com)
  • Bilirubin staining of the brain without accompanying neuronal necrosis can be observed in babies who did not demonstrate clinical signs of bilirubin encephalopathy but who succumbed from other causes. (medscape.com)
  • Using animal models and studying human brain, his laboratory has shown that dysfunction in the BBB and brain microcirculation can accumulate before neuronal loss and is an early biomarker of human cognitive dysfunction. (usc.edu)
  • These findings emphasize the complex interactions between brain serotonergic pathways and non-neuronal cells within the CNS and, further, they raise the possibility that some of these receptors may be activated by antimigraine compounds such as brain penetrant triptan derivatives. (diigo.com)
  • 2 Because it crosses the blood brain barrier, RRx-001 is also under study in Parkinson's Disease, Amyotrophic Lateral Sclerosis (ALS)/motor neuron dis-ease (MND), and Alzheimer's Disease having been awarded grants as an inflammasome inhibitor by the Michael J Fox Foun-dation (MJFF) and other funding organizations for neurodegen-erative diseases. (drug-dev.com)
  • Arimoclomol is administered orally, crosses the blood brain barrier, and has been studied in seven Phase 1, four Phase 2 and one pivotal Phase 2/3 clinical trial. (biospace.com)
  • The second stage starts when the parasite crosses the blood-brain barrier and invades the central nervous system, causing severe neurological disorders. (who.int)
  • The blood-brain barrier acts effectively to protect brain tissue from circulating pathogens and other potentially toxic substances. (wikipedia.org)
  • The search for specific therapies for multiple sclerosis has prompted an international research group to investigate how immune cells can cross the blood-brain barrier and trigger inflammatory processes in nerve tissue. (fwf.ac.at)
  • To this end they have to be equipped with special molecules that dock on with great precision at a few checkpoints within this tissue barrier. (fwf.ac.at)
  • The research groups involved in this endeavour are closely interconnected, almost mirroring the closely-knit tissue of the blood-brain barrier. (fwf.ac.at)
  • In conclusion, the beneficial effects of gelatin may be the combined results of faster healing of the blood brain barrier curtailing leakage of blood borne molecules/cells into brain parenchyma and to a modulation of the microglial population response favoring restitution of the injured tissue. (lu.se)
  • We initiated program on BBB molecular signatures (snRNAseq, proteome) in health and disease using transgenic and human models, and human brain tissue. (usc.edu)
  • it protects the brain's delicate nerve tissue by preventing many other types of molecules from entering the brain. (medlineplus.gov)
  • Brain herniation occurs when increased intracranial pressure causes the abnormal protrusion of brain tissue through openings in rigid intracranial barriers (eg, tentorial notch). (msdmanuals.com)
  • Because the skull is rigid after infancy, intracranial masses or swelling may increase intracranial pressure, sometimes causing protrusion (herniation) of brain tissue through one of the rigid intracranial barriers (tentorial notch, falx cerebri, foramen magnum). (msdmanuals.com)
  • Brain herniation is classified based on the structure through which tissue is herniated. (msdmanuals.com)
  • Increased intracranial pressure sometimes causes protrusion (herniation) of brain tissue through one of the rigid intracranial barriers (tentorial notch, falx cerebri, foramen magnum). (msdmanuals.com)
  • A team co-chaired by Gad Vatine of BGU's Regenerative Medicine and Stem Cell Research Center and Clive N. Svendsen of Cedars-Sinai's Board of Governors Regenerative Medicine Institute collected blood cells from individuals and genetically manipulated into stem cells (induced pluripotent stem cells), which they used to make the neurons, blood-vessel cells and support cells of the BBB. (amazinghealthadvances.net)
  • The GLUT1 protein also moves glucose between cells in the brain called glia, which protect and maintain nerve cells (neurons). (medlineplus.gov)
  • While the role of the blood-brain barrier is increasingly recognized in the development of neurodegenerative disorders, such as Alzheimer's disease, dysfunction of the blood-brain barrier has been linked to stress-related psychiatric diseases only recently. (sigmaaldrich.com)
  • Microvascular changes often involve pathological pericyte activation and bloodbrain barrier dysfunction. (lu.se)
  • Neurovascular dysfunction, including blood-brain barrier (BBB) breakdown and cerebral blood flow (CBF) dysregulation and reduction, is increasingly recognized as contributing to Alzheimer disease. (medscape.com)
  • SCOTTSDALE, Arizona - Distinctive signs of breakdown of the blood-brain barrier (BBB) are commonly evident in patients with reversible cerebral vasoconstriction syndrome (RCVS), providing potential diagnostic clues for the serious condition even in the absence of vasoconstriction. (medscape.com)
  • A variety of imaging modalities, including structural and functional magnetic resonance imaging (MRI) and positron emission tomography (PET) studies of cerebral metabolism, have shown characteristic changes in the brain of patients with Alzheimer disease in prodromal and even presymptomatic states. (medscape.com)
  • Cells of the barrier actively transport metabolic products such as glucose across the barrier using specific transport proteins. (wikipedia.org)
  • Nevertheless, in the treatment of neurodegenerative diseases such as Parkinson's, Alzheimer's, diffuse intrinsic pontine glioma , and other brain cancers , drugs must reach CNS. (bvsalud.org)
  • He has identified genes and receptors at the BBB that regulate brain levels of Alzheimer's amyloid-beta toxin, which accumulates with aging and in AD. (usc.edu)
  • The blood-brain barrier restricts the passage of pathogens, the diffusion of solutes in the blood, and large or hydrophilic molecules into the cerebrospinal fluid, while allowing the diffusion of hydrophobic molecules (O2, CO2, hormones) and small non-polar molecules. (wikipedia.org)
  • The barrier also restricts the passage of peripheral immune factors, like signaling molecules, antibodies, and immune cells, into the CNS, thus insulating the brain from damage due to peripheral immune events. (wikipedia.org)
  • RESULTS: We report a lack of abnormal increase in adsorptive-mediated transcytosis of albumin and preserved paracellular barrier for fibrinogen and small molecules despite an extensive load of Aβ. (lu.se)
  • A group in Montreal (Canada), for instance, focused on the identification of specific form-fitting molecules that dock at the checkpoints of the blood-brain barrier. (fwf.ac.at)
  • Blood-brain barrier (BBB) serves as an essential interface between central nervous system (CNS) and its periphery, allowing selective permeation of ions , gaseous molecules, and other nutrients to maintain metabolic functions of brain . (bvsalud.org)
  • Antibodies are too large to cross the blood-brain barrier, and only certain antibiotics are able to pass. (wikipedia.org)
  • However, the blood-brain barrier (BBB) restricts Rg1 in reaching the CNS. (altmetric.com)
  • Overexpression of the Parkinson-related protein, α-synuclein, leads to blood-brain barrier leakage and pericyte activation in mice. (lu.se)
  • Interestingly, changes such as pericyte activation and blood-brain-barrier leakage are already observed at the early stages of the disorder, even before behavioral changes or dopaminergic cell loss can be detected, explains Gesine Paul-Visse. (lu.se)
  • Pericytes: a link between Parkinson-related protein and blood-brain barrier disruption? (lu.se)
  • Disruption of the blood-brain barrier and other microvascular alterations are increasingly recognized as a common denominator of several neurodegenerative disorders. (lu.se)
  • In contrast, messages for all 5-HT receptors tested were detected in human brain astrocytes with a predominance of the 5-HT2A and 5-HT7 subtypes. (diigo.com)
  • Hence, it is possible that the dysregulation of the blood-brain barrier induced by α-synuclein depends on pericytes also in the brain. (lu.se)
  • Their achievement - detailed in a study published in the journal Cell Stem Cell - provides a new way to study brain disorders and, potentially, predict which drugs will work best for each patient. (amazinghealthadvances.net)
  • Pericytes are uniquely positioned at the blood-brain interface. (lu.se)
  • Significantly, when the BBB-Chip was derived from cells of patients with Allan-Herndon-Dudley syndrome or Huntington disease, the barrier malfunctioned in the same way that it does in patients with these diseases. (amazinghealthadvances.net)
  • Comment: The author believes that: 'Serotonin plays a role in the brain and pharmacological interference with its function may influence mental and neurological processes. (erowid.org)
  • The BBB is distinct from the quite similar blood-cerebrospinal fluid barrier, which is a function of the choroidal cells of the choroid plexus, and from the blood-retinal barrier, which can be considered a part of the whole realm of such barriers. (wikipedia.org)
  • 2014 . Aging-induced type I interferon response at the choroid plexus negatively affects brain function. (annualreviews.org)
  • 2013 . CNS-specific immunity at the choroid plexus shifts toward destructive Th2 inflammation in brain aging. (annualreviews.org)
  • where it transports a simple sugar called glucose into cells from the blood or from other cells for use as fuel. (medlineplus.gov)
  • In the brain, the GLUT1 protein is involved in moving glucose, which is the brain's main energy source, across the blood-brain barrier. (medlineplus.gov)
  • Having less functional GLUT1 protein reduces the amount of glucose available to brain cells, which affects brain development and function. (medlineplus.gov)
  • abstract = "Gelatin coating of brain implants is known to provide considerable benefits in terms of reduced inflammatory sequalae and long-term neuroprotective effects. (lu.se)
  • Zlokovic studies the role of brain microcirculation, particularly the blood-brain barrier (BBB) in health and disease in the adult and aging brain. (usc.edu)
  • The most common complaints related to visual problems associated with brain injuries include light sensitivity, headaches, double vision, fatigue, dizziness, difficulty reading, or loss of peripheral visual fields. (brainline.org)
  • Peripheral injection of serotonin has no effect on the brain but the natural precursor, 5-hydroxytryptophane, passes the blood-brain barrier and increases the serotonin content of the brain. (erowid.org)
  • Peripheral blood smear showed hypochromia and microcytosis. (cdc.gov)
  • In summary, the polarized distribution of these transport systems between the luminal and abluminal membranes, and the fact that more than one transporter may carry the same substrate, ensures supply and excretion of AAs in and out of the brain, thereby controlling its homeostasis and proper function. (frontiersin.org)
  • The function of the blood-brain barrier (BBB) can be impaired by free radicals. (mdc-berlin.de)
  • His team has developed new imaging techniques for studying BBB function in animal models and the living human brain. (usc.edu)
  • Abnormal BBB function several behavioural manifestations, such frequently occurs with brain damage. (who.int)
  • Accordingly, blood-borne infections of the brain are rare. (wikipedia.org)
  • Infections of the brain that do occur are often difficult to treat. (wikipedia.org)
  • NT008 trade name] is indicated in adults and children for the elimination through mass drug administration programmes of schistosoma infections due to various types of blood fluke worms ( Schistosoma mansoni, Schistosoma haematobium, Schistosoma japonicum, Schistosoma mekongi, Schistosoma intercalatum ) following the recommendations of the WHO Global Programme to Eliminate Schistosomiasis. (who.int)
  • In fact, tight junctions of ECs give rise to a polarized cell composed of two distinct luminal (blood-side) and abluminal (brain-side) surfaces. (frontiersin.org)
  • In some cases, a drug has to be administered directly into the cerebrospinal fluid where it can enter the brain by crossing the blood-cerebrospinal fluid barrier. (wikipedia.org)
  • The cerebellar tonsils, forced through the foramen magnum, compress the brain stem and obstruct cerebrospinal fluid (CSF) flow. (msdmanuals.com)
  • The pineal gland secretes the hormone melatonin "directly into the systemic circulation", thus melatonin is not affected by the blood-brain barrier. (wikipedia.org)
  • 2014 . Aging and brain rejuvenation as systemic events. (annualreviews.org)
  • These results show that specific populations of functional 5-HT receptors are differentially distributed within the various cellular compartments of the human cortical microvascular bed, and that human brain astroglial cells are endowed with multiple 5-HT receptors. (diigo.com)
  • Babies with common GLUT1 deficiency syndrome have a normal head size at birth, but growth of the brain and skull is often slow, which can result in an abnormally small head size ( microcephaly ). (medlineplus.gov)
  • Neuroimaging is widely believed to be generally useful for excluding reversible causes of dementia syndrome such as normal-pressure hydrocephalus, brain tumor, and subdural hematoma, and for excluding other likely causes of dementia such as cerebrovascular disease. (medscape.com)
  • The results obtained by the Center for Brain Research in Vienna show that the development of this inflammatory disease is dominated by two types of immune cells which represent an important basis for more specific therapies. (fwf.ac.at)
  • In the international research association MELTRA BBB, specialized research groups are jointly investigating which immune cells can penetrate the brain and trigger inflammation and how they do it. (fwf.ac.at)
  • White blood cells, specifically T lymphocytes and B lymphocytes, can only pass to a minor extent if required for immune defence. (fwf.ac.at)
  • In Toulouse (France), the path of CD8+ T cells into the brain of mice was studied in experiments. (fwf.ac.at)
  • News Staff via Israel21c - Using stem cells and microfluidic chips, they fashion a functioning copy of a patient's brain structure to tailor treatment. (amazinghealthadvances.net)
  • But researchers at Israel's Ben-Gurion University and Cedars-Sinai Medical Center in Los Angeles have done something almost as astounding: on a chip, they've duplicated patients' blood-brain barrier (BBB) using the individuals' own cells. (amazinghealthadvances.net)
  • They placed these various types of cells inside microfluidic chips that mimic the environment in which cells interact with each other and with blood. (amazinghealthadvances.net)
  • Although scientists have created blood-brain barriers outside the body before, the investigators said they believe this is the first time such a structure has been created from induced pluripotent stem cells that were derived from a patient, matched the patient's DNA and displayed a characteristic defect of the patient's disease. (amazinghealthadvances.net)
  • In collaboration, they investigated how a progressive accumulation of α-synuclein affects these cells and brain vasculature over time. (lu.se)
  • which is characterized by a shortage of red blood cells. (medlineplus.gov)
  • Certain human brain cells, oligodendroglia, react to serotonin with strong contraction. (erowid.org)
  • This type can occur when an infratentorial mass (eg, tumor in the posterior fossa, cerebellar hemorrhage) compresses the brain stem, kinking it and causing patchy brain stem ischemia. (msdmanuals.com)
  • There was no evidence of blood loss, and stool examination was negative for occult blood. (cdc.gov)
  • and serum indicated rupture of the blood-brain barrier. (cdc.gov)
  • Serum-borne bioactivity caused by pulmonary multiwalled carbon nanotube s induces neuroinflammation via blood-brain barrier impairment. (cdc.gov)
  • About one in a thousand individuals suffers from this chronic inflammation of the central nervous system, which is scattered in the brain and spinal cord. (fwf.ac.at)
  • The protein complexes that control cell-cell attachment also polarize cellular membrane, so that it can be divided into luminal (blood-facing) and abluminal (brain) sides, and each solute that enters/leaves the brain must cross both membranes. (frontiersin.org)
  • [ 1 ] The term kernicterus literally means "yellow kern," with kern indicating the most commonly afflicted region of the brain (ie, the nuclear region). (medscape.com)
  • As mentioned above, a common symptom of traumatic brain injury is hypersensitivity to sound. (brainline.org)
  • These are custom-fitted earplugs, originally made for musicians, but they now have been adapted for individuals with traumatic brain injuries. (brainline.org)
  • Increasing knowledge about these mechanisms could unravel possible targets for early treatments and protection of the blood-brain barrier. (lu.se)
  • However, the mechanisms for gelatin's protective role in brain injury are still unknown. (lu.se)
  • Both temporal lobes herniate through the tentorial notch because of bilateral mass effects or diffuse brain edema. (msdmanuals.com)
  • Given the key importance of the BBB for normal brain functions, we believe our findings have substantial significance and will be highly interesting to researchers in the biomaterial field. (lu.se)
  • MRI can be considered the preferred neuroimaging examination for Alzheimer disease because it allows accurate measurement of the 3-dimensional (3D) volume of brain structures, especially the size of the hippocampus and related regions. (medscape.com)
  • The BBB acts as a gatekeeper by blocking toxins and other foreign substances in the bloodstream from entering the brain. (amazinghealthadvances.net)
  • The term blood-brain barrier (BBB) was used to describe the unique characteristics of the microvasculature of the central nervous system (CNS). (frontiersin.org)
  • The blood-brain barrier isolates the central nervous system (i.e. brain and spinal cord) and prevents the intrusion of substances that circulate in the body but are not wanted in the control centre. (fwf.ac.at)
  • Treatment of hypertension, to lower blood pressure. (nih.gov)
  • HYZAAR ® is indicated for the treatment of hypertension, to lower blood pressure. (nih.gov)
  • This fantastic stuff was proposed last year as a way to simultaneously record signals throughout the entire brain (Opens in a new window) . (extremetech.com)