Connections between cells which allow passage of small molecules and electric current. Gap junctions were first described anatomically as regions of close apposition between cells with a narrow (1-2 nm) gap between cell membranes. The variety in the properties of gap junctions is reflected in the number of CONNEXINS, the family of proteins which form the junctions.
A group of homologous proteins which form the intermembrane channels of GAP JUNCTIONS. The connexins are the products of an identified gene family which has both highly conserved and highly divergent regions. The variety contributes to the wide range of functional properties of gap junctions.
A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.
Direct contact of a cell with a neighboring cell. Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p792)
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)
Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.
An agent derived from licorice root. It is used for the treatment of digestive tract ulcers, especially in the stomach. Antidiuretic side effects are frequent, but otherwise the drug is low in toxicity.
Anchoring points where the CYTOSKELETON of neighboring cells are connected to each other. They are composed of specialized areas of the plasma membrane where bundles of the ACTIN CYTOSKELETON attach to the membrane through the transmembrane linkers, CADHERINS, which in turn attach through their extracellular domains to cadherins in the neighboring cell membranes. In sheets of cells, they form into adhesion belts (zonula adherens) that go all the way around a cell.
An oleanolic acid from GLYCYRRHIZA that has some antiallergic, antibacterial, and antiviral properties. It is used topically for allergic or infectious skin inflammation and orally for its aldosterone effects in electrolyte regulation.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
A colorless liquid with a fragrant odor. It is used as an intermediate, solvent and in cosmetics.
The synapse between a neuron and a muscle.
Isomeric forms and derivatives of octanol (C8H17OH).
A 195-kDa zonula occludens protein that is distinguished by the presence of a ZU5 domain at the C-terminal of the molecule.
Specialized junctions between NEURONS which connect the cytoplasm of one neuron to another allowing direct passage of an ion current.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)
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.
A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.
A MARVEL domain protein that plays an important role in the formation and regulation of the TIGHT JUNCTION paracellular permeability barrier.
The area covering the terminal portion of ESOPHAGUS and the beginning of STOMACH at the cardiac orifice.
A colorless, slightly viscous liquid used as a defoaming or wetting agent. It is also used as a solvent for protective coatings, waxes, and oils, and as a raw material for plasticizers. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Calcium-dependent cell adhesion proteins. They are important in the formation of ADHERENS JUNCTIONS between cells. Cadherins are classified by their distinct immunological and tissue specificities, either by letters (E- for epithelial, N- for neural, and P- for placental cadherins) or by numbers (cadherin-12 or N-cadherin 2 for brain-cadherin). Cadherins promote cell adhesion via a homophilic mechanism as in the construction of tissues and of the whole animal body.
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.
The ability of a substrate to allow the passage of ELECTRONS.
Proteins that take part in the formation or structure of TIGHT JUNCTIONS.
A type of junction that attaches one cell to its neighbor. One of a number of differentiated regions which occur, for example, where the cytoplasmic membranes of adjacent epithelial cells are closely apposed. It consists of a circular region of each membrane together with associated intracellular microfilaments and an intercellular material which may include, for example, mucopolysaccharides. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990; Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Enzymes that recognize CRUCIFORM DNA structures and introduce paired incisions that help to resolve the structure into two DNA helices.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
An organochlorine insecticide that has been used as a pediculicide and a scabicide. It has been shown to cause cancer.
Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
'Eye proteins' are structural or functional proteins, such as crystallins, opsins, and collagens, located in various parts of the eye, including the cornea, lens, retina, and aqueous humor, that contribute to maintaining transparency, refractive power, phototransduction, and overall integrity of the visual system.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Established cell cultures that have the potential to propagate indefinitely.
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.
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.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Endogenously-synthesized compounds that influence biological processes not otherwise classified under ENZYMES; HORMONES or HORMONE ANTAGONISTS.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A zonula occludens protein subtype found in epithelial cell junctions. Several isoforms of zonula occludens-2 protein exist due to use of alternative promoter regions and alternative mRNA splicings.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
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.
Lanthanum. The prototypical element in the rare earth family of metals. It has the atomic symbol La, atomic number 57, and atomic weight 138.91. Lanthanide ion is used in experimental biology as a calcium antagonist; lanthanum oxide improves the optical properties of glass.
A cross-shaped DNA structure that can be observed under the electron microscope. It is formed by the incomplete exchange of strands between two double-stranded helices or by complementary INVERTED REPEAT SEQUENCES that refold into hairpin loops on opposite strands across from each other.
One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
An integral membrane protein that is localized to TIGHT JUNCTIONS, where it plays a role in controlling the paracellular permeability of polarized cells. Mutations in the gene for claudin-1 are associated with Neonatal Ichthyosis-Sclerosing Cholangitis (NISCH) Syndrome.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
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.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
The resistance to the flow of either alternating or direct electrical current.
Elements of limited time intervals, contributing to particular results or situations.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.
The smooth muscle coat of the uterus, which forms the main mass of the organ.
Refers to animals in the period of time just after birth.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
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.
Phosphoproteins are proteins that have been post-translationally modified with the addition of a phosphate group, usually on serine, threonine or tyrosine residues, which can play a role in their regulation, function, interaction with other molecules, and localization within the cell.
Desmoplakins are cytoskeletal linker proteins that anchor INTERMEDIATE FILAMENTS to the PLASMA MEMBRANE at DESMOSOMES.
A catenin that binds F-ACTIN and links the CYTOSKELETON with BETA CATENIN and GAMMA CATENIN.
A water-soluble, enzyme co-factor present in minute amounts in every living cell. It occurs mainly bound to proteins or polypeptides and is abundant in liver, kidney, pancreas, yeast, and milk.
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.
Chemicals and substances that impart color including soluble dyes and insoluble pigments. They are used in INKS; PAINTS; and as INDICATORS AND REAGENTS.
The result of a positive or negative response (to drugs, for example) in one cell being passed onto other cells via the GAP JUNCTIONS or the intracellular milieu.
Adherence of cells to surfaces or to other cells.
A method used to study the lateral movement of MEMBRANE PROTEINS and LIPIDS. A small area of a cell membrane is bleached by laser light and the amount of time necessary for unbleached fluorescent marker-tagged proteins to diffuse back into the bleached site is a measurement of the cell membrane's fluidity. The diffusion coefficient of a protein or lipid in the membrane can be calculated from the data. (From Segen, Current Med Talk, 1995).
A complex of polyene antibiotics obtained from Streptomyces filipinensis. Filipin III alters membrane function by interfering with membrane sterols, inhibits mitochondrial respiration, and is proposed as an antifungal agent. Filipins I, II, and IV are less important.
Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.
A modification of the freeze-drying method in which the ice within the frozen tissue is replaced by alcohol or other solvent at a very low temperature.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
Conditions characterized by impaired transmission of impulses at the NEUROMUSCULAR JUNCTION. This may result from disorders that affect receptor function, pre- or postsynaptic membrane function, or ACETYLCHOLINESTERASE activity. The majority of diseases in this category are associated with autoimmune, toxic, or inherited conditions.
The portion of the crystalline lens surrounding the nucleus and bound anteriorly by the epithelium and posteriorly by the capsule. It contains lens fibers and amorphous, intercellular substance.
Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.
Major constituent of the cytoskeleton found in the cytoplasm of eukaryotic cells. They form a flexible framework for the cell, provide attachment points for organelles and formed bodies, and make communication between parts of the cell possible.
The epithelium lining the seminiferous tubules composed of primary male germ cells (SPERMATOGONIA) and supporting SERTOLI CELLS. As SPERMATOGENESIS proceeds, the developing germ cells migrate toward the lumen. The adluminal compartment, the inner two thirds of the tubules, contains SPERMATOCYTES and the more advanced germ cells.
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.
Supporting cells projecting inward from the basement membrane of SEMINIFEROUS TUBULES. They surround and nourish the developing male germ cells and secrete ANDROGEN-BINDING PROTEIN and hormones such as ANTI-MULLERIAN HORMONE. The tight junctions of Sertoli cells with the SPERMATOGONIA and SPERMATOCYTES provide a BLOOD-TESTIS BARRIER.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
The hollow, muscular organ that maintains the circulation of the blood.

The bystander effect in the HSVtk/ganciclovir system and its relationship to gap junctional communication. (1/2680)

The bystander effect (BSE) is an interesting and important property of the herpes thymidine kinase/ganciclovir (hTK/GCV) system of gene therapy for cancer. With the BSE, not only are the hTK expressing cells killed upon ganciclovir (GCV) exposure but also neighboring wild-type tumor cells. On testing a large number of tumor cell lines in vitro, a wide range of sensitivity to bystander killing was found. Since transfer of toxic GCV metabolites from hTK-modified to wild-type tumor cells via gap junctions (GJ) seemed to be a likely mechanism of the BSE, we tested GJ function in these various tumors with a dye transfer technique and pharmacological agents known to affect GJ communication. We confirmed that mixtures of tumor cell resistant to the BSE did not show dye transfer from cell to cell while bystander-sensitive tumor cells did. Dieldrin, a drug known to decrease GJ communication, diminished dye transfer and also inhibited the BSE. Forskolin, an upregulator of cAMP did increase GJ, but directly inhibited hTK and therefore its effect on BSE could not be determined. We conclude that these observations further support port the concept that functional GJ play an important role in the BSE and further suggest that pharmacological manipulation of GJ may influence the outcome of cancer therapy with hTK/GCV.  (+info)

Three-dimensional structure of a recombinant gap junction membrane channel. (2/2680)

Gap junction membrane channels mediate electrical and metabolic coupling between adjacent cells. The structure of a recombinant cardiac gap junction channel was determined by electron crystallography at resolutions of 7.5 angstroms in the membrane plane and 21 angstroms in the vertical direction. The dodecameric channel was formed by the end-to-end docking of two hexamers, each of which displayed 24 rods of density in the membrane interior, which is consistent with an alpha-helical conformation for the four transmembrane domains of each connexin subunit. The transmembrane alpha-helical rods contrasted with the double-layered appearance of the extracellular domains. Although not indicative for a particular type of secondary structure, the protein density that formed the extracellular vestibule provided a tight seal to exclude the exchange of substances with the extracellular milieu.  (+info)

Morphogenesis of the Caenorhabditis elegans male tail tip. (3/2680)

Using electron microscopy and immunofluorescent labeling of adherens junctions, we have reconstructed the changes in cell architecture and intercellular associations that occur during morphogenesis of the nematode male tail tip. During late postembryonic development, the Caenorhabditis elegans male tail is reshaped to form a copulatory structure. The most posterior hypodermal cells in the tail define a specialized, sexually dimorphic compartment in which cells fuse and retract in the male, changing their shape from a tapered cone to a blunt dome. Developmental profiles using electron microscopy and immunofluorescent staining suggest that cell fusions are initiated at or adjacent to adherens junctions. Anterior portions of the tail tip cells show the first evidence of retractions and fusions, consistent with our hypothesis that an anterior event triggers these morphogenetic events. Available mutations that interfere with morphogenesis implicate particular regulatory pathways and suggest loci at which evolutionary changes could have produced morphological diversity.  (+info)

Gap junction signalling mediated through connexin-43 is required for chick limb development. (4/2680)

During chick limb development the gap junction protein Connexin-43 (Cx43) is expressed in discrete spatially restricted domains in the apical ectodermal ridge (AER) and mesenchyme of the zone of polarising activity. Antisense oligonucleotides (ODNs) were used to investigate the role of Connexin-43 (Cx43) in the development of the chick limb bud. We have used unmodified ODNs in Pluronic F-127 gel, which is liquid at low temperature but sets at room temperature and so remains situated at the point of application. As a mild surfactant, the gel increases antisense ODN penetration and supplies ODNs to the embryo continually for 12-18 h. We have shown a strong decrease in Cx43 protein expression after application of specific antisense oligonucleotides but the abundance of a closely related protein, Connexin-32 (Cx32), was not affected. Application of antisense Cx43 ODNs at stages 8-15 HH before limb outgrowth resulted in dramatic limb phenotypes. About 40% of treated embryos exhibited defects such as truncation of the limb bud, fragmentation into two or more domains, or complete splitting of the limb bud into two or three branches. Molecular analysis of antisense treated embryos failed to detect Shh or Bmp-2 in anterior structures and suggested that extra lobes seen in nicked and split limbs were not a result of establishment of new signalling centres as found after the application of FGF to the flank. However, examination of markers for the AER showed a number of abnormalities. In severely truncated specimens we were unable to detect the expression of either Fgf-4 or Fgf-8. In both nicked and split limbs the expression of these genes was discontinuous. Down-regulation of Cx43 after the antisense application could be comparable to AER removal and results in distal truncation of the limb bud. Taken together these data suggest the existence of a feedback loop between the FGFs and signalling mediated by Cx43.  (+info)

Chemical signaling from colonic smooth muscle cells to DRG neurons in culture. (5/2680)

Transduction mechanisms between target cells within the intestinal wall and peripheral terminals of extrinsic primary afferent neurons are poorly understood. The purpose of this study was to characterize the interactions between smooth muscle cells from the rat distal colon and lumbar dorsal root ganglion (DRG) neurons in coculture. DRG neurons visually appeared to make contact with several myocytes. We show that brief mechanical stimulation of these myocytes resulted in intracellular Ca2+ concentration ([Ca2+]i) transients that propagated into 57% of the contacting neurites. Direct mechanical stimulation of DRG neurites cultured without smooth muscle had no effect. We also show that colonic smooth muscle cells express multiple connexin mRNAs and that these connexins formed functional gap junctions, as evidenced by the intercellular transfer of Lucifer yellow. Furthermore, thapsigargin pretreatment and neuronal heparin injection abolished the increase in neurite [Ca2+]i, indicating that the neuronal Ca2+ signal was triggered by inositol 1,4, 5-trisphosphate-mediated Ca2+ release from intracellular stores. Our results provide evidence for intercellular chemical communication between DRG neurites and intestinal smooth muscle cells that mediates the exchange of second messenger molecules between different cell types.  (+info)

Spatial and temporal regulation of gap junction connexin43 in vascular endothelial cells exposed to controlled disturbed flows in vitro. (6/2680)

Hemodynamic regulation of the endothelial gap junction protein connexin43 (Cx43) was studied in a model of controlled disturbed flows in vitro. Cx43 mRNA, protein expression, and intercellular communication were mapped to spatial variations in fluid forces. Hemodynamic features of atherosclerotic lesion-prone regions of the vasculature (flow separation and recirculation) were created for periods of 5, 16, and 30 h, with laminar shear stresses ranging between 0 and 13.5 dynes/cm2. Within 5 h, endothelial Cx43 mRNA expression was increased in all cells when compared with no-flow controls, with highest levels (up to 6- to 8-fold) expressed in regions of flow recirculation corresponding to high shear stress gradients. At 16 h, Cx43 mRNA expression remained elevated in regions of flow disturbance, whereas in areas of fully developed, undisturbed laminar flow, Cx43 expression returned to control levels. In all flow regions, typical punctate Cx43 immunofluorescence at cell borders was disrupted by 5 h. After 30 h of flow, disruption of gap junctions persisted in cells subjected to flow separation and recirculation, whereas regions of undisturbed flow were substantially restored to normal. These expression differences were reflected in sustained inhibition of intercellular communication (dye transfer) throughout the zone of disturbed flow (84.2 and 68.4% inhibition at 5 and 30 h, respectively); in contrast, communication was fully reestablished by 30 h in cells exposed to undisturbed flow. Up-regulation of Cx43 transcripts, sustained disorganization of Cx43 protein, and impaired communication suggest that shear stress gradients in regions of disturbed flow regulate intercellular communication through the expression and function of Cx43.  (+info)

Intracellular trafficking pathways in the assembly of connexins into gap junctions. (7/2680)

Trafficking pathways underlying the assembly of connexins into gap junctions were examined using living COS-7 cells expressing a range of connexin-aequorin (Cx-Aeq) chimeras. By measuring the chemiluminescence of the aequorin fusion partner, the translocation of oligomerized connexins from intracellular stores to the plasma membrane was shown to occur at different rates that depended on the connexin isoform. Treatment of COS-7 cells expressing Cx32-Aeq and Cx43-Aeq with brefeldin A inhibited the movement of these chimera to the plasma membrane by 84 +/- 4 and 88 +/- 4%, respectively. Nocodazole treatment of the cells expressing Cx32-Aeq and Cx43-Aeq produced 29 +/- 16 and 4 +/- 7% inhibition, respectively. In contrast, the transport of Cx26 to the plasma membrane, studied using a construct (Cx26/43T-Aeq) in which the short cytoplasmic carboxyl-terminal tail of Cx26 was replaced with the extended carboxyl terminus of Cx43, was inhibited 89 +/- 5% by nocodazole and was minimally affected by exposure of cells to brefeldin A (17 +/-11%). The transfer of Lucifer yellow across gap junctions between cells expressing wild-type Cx32, Cx43, and the corresponding Cx32-Aeq and Cx43-Aeq chimeras was reduced by nocodazole treatment and abolished by brefeldin A treatment. However, the extent of dye coupling between cells expressing wild-type Cx26 or the Cx26/43T-Aeq chimeras was not significantly affected by brefeldin A treatment, but after nocodazole treatment, transfer of dye to neighboring cells was greatly reduced. These contrasting effects of brefeldin A and nocodazole on the trafficking properties and intercellular dye transfer are interpreted to suggest that two pathways contribute to the routing of connexins to the gap junction.  (+info)

Dissection of the molecular basis of pp60(v-src) induced gating of connexin 43 gap junction channels. (8/2680)

Suppression of gap-junctional communication by various protein kinases, growth factors, and oncogenes frequently correlates with enhanced mitogenesis. The oncogene v-src appears to cause acute closure of gap junction channels. Tyr265 in the COOH-terminal tail of connexin 43 (Cx43) has been implicated as a potential target of v-src, although v-src action has also been associated with changes in serine phosphorylation. We have investigated the mechanism of this acute regulation through mutagenesis of Cx43 expressed in Xenopus laevis oocyte pairs. Truncations of the COOH-terminal domain led to an almost complete loss of response of Cx43 to v-src, but this was restored by coexpression of the independent COOH-terminal polypeptide. This suggests a ball and chain gating mechanism, similar to the mechanism proposed for pH gating of Cx43, and K+ channel inactivation. Surprisingly, we found that v-src mediated gating of Cx43 did not require the tyrosine site, but did seem to depend on the presence of two potential SH3 binding domains and the mitogen-activated protein (MAP) kinase phosphorylation sites within them. Further point mutagenesis and pharmacological studies in normal rat kidney (NRK) cells implicated MAP kinase in the gating response to v-src, while the stable binding of v-src to Cx43 (in part mediated by SH3 domains) did not correlate with its ability to mediate channel closure. This suggests a common link between closure of gap junctions by v-src and other mitogens, such as EGF and lysophosphatidic acid (LPA).  (+info)

Gap junctions are specialized intercellular connections that allow for the direct exchange of ions, small molecules, and electrical signals between adjacent cells. They are composed of arrays of channels called connexons, which penetrate the cell membranes of two neighboring cells and create a continuous pathway for the passage of materials from one cytoplasm to the other. Each connexon is formed by the assembly of six proteins called connexins, which are encoded by different genes and vary in their biophysical properties. Gap junctions play crucial roles in many physiological processes, including the coordination of electrical activity in excitable tissues, the regulation of cell growth and differentiation, and the maintenance of tissue homeostasis. Mutations or dysfunctions in gap junction channels have been implicated in various human diseases, such as cardiovascular disorders, neurological disorders, skin disorders, and cancer.

Connexins are a family of proteins that form the structural units of gap junctions, which are specialized channels that allow for the direct exchange of small molecules and ions between adjacent cells. These channels play crucial roles in maintaining tissue homeostasis, coordinating cellular activities, and enabling communication between cells. In humans, there are 21 different connexin genes that encode for these proteins, with each isoform having unique properties and distributions within the body. Mutations in connexin genes have been linked to a variety of human diseases, including hearing loss, skin disorders, and heart conditions.

Connexin 43 is a protein that forms gap junctions, which are specialized channels that allow for the direct communication and transport of small molecules between adjacent cells. Connexin 43 is widely expressed in many tissues, including the heart, brain, and various types of epithelial and connective tissues. In the heart, connexin 43 plays a crucial role in electrical conduction and coordination of contraction between cardiac muscle cells. Mutations in the gene that encodes connexin 43 have been associated with several human diseases, including certain types of cardiac arrhythmias and skin disorders.

Intercellular junctions are specialized areas of contact between two or more adjacent cells in multicellular organisms. They play crucial roles in maintaining tissue structure and function by regulating the movement of ions, molecules, and even larger cellular structures from one cell to another. There are several types of intercellular junctions, including:

1. Tight Junctions (Zonulae Occludentes): These are the most apical structures in epithelial and endothelial cells, forming a virtually impermeable barrier to prevent the paracellular passage of solutes and water between the cells. They create a tight seal by connecting the transmembrane proteins of adjacent cells, such as occludin and claudins.
2. Adherens Junctions: These are located just below the tight junctions and help maintain cell-to-cell adhesion and tissue integrity. Adherens junctions consist of cadherin proteins that form homophilic interactions with cadherins on adjacent cells, as well as intracellular adaptor proteins like catenins, which connect to the actin cytoskeleton.
3. Desmosomes: These are another type of cell-to-cell adhesion structure, primarily found in tissues that experience mechanical stress, such as the skin and heart. Desmosomes consist of cadherin proteins (desmocadherins) that interact with each other and connect to intermediate filaments (keratin in epithelial cells) via plakoglobin and desmoplakin.
4. Gap Junctions: These are specialized channels that directly connect the cytoplasm of adjacent cells, allowing for the exchange of small molecules, ions, and second messengers. Gap junctions consist of connexin proteins that form hexameric structures called connexons in the plasma membrane of each cell. When two connexons align, they create a continuous pore or channel between the cells.

In summary, intercellular junctions are essential for maintaining tissue structure and function by regulating paracellular transport, cell-to-cell adhesion, and intercellular communication.

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.

Cell communication, also known as cell signaling, is the process by which cells exchange and transmit signals between each other and their environment. This complex system allows cells to coordinate their functions and maintain tissue homeostasis. Cell communication can occur through various mechanisms including:

1. Autocrine signaling: When a cell releases a signal that binds to receptors on the same cell, leading to changes in its behavior or function.
2. Paracrine signaling: When a cell releases a signal that binds to receptors on nearby cells, influencing their behavior or function.
3. Endocrine signaling: When a cell releases a hormone into the bloodstream, which then travels to distant target cells and binds to specific receptors, triggering a response.
4. Synaptic signaling: In neurons, communication occurs through the release of neurotransmitters that cross the synapse and bind to receptors on the postsynaptic cell, transmitting electrical or chemical signals.
5. Contact-dependent signaling: When cells physically interact with each other, allowing for the direct exchange of signals and information.

Cell communication is essential for various physiological processes such as growth, development, differentiation, metabolism, immune response, and tissue repair. Dysregulation in cell communication can contribute to diseases, including cancer, diabetes, and neurological disorders.

Carbenoxolone is a synthetic derivative of glycyrrhizin, which is found in the root of the licorice plant. It has been used in the treatment of gastric and duodenal ulcers due to its ability to increase the mucosal resistance and promote healing. Carbenoxolone works by inhibiting the enzyme 11-beta-hydroxysteroid dehydrogenase, which leads to an increase in the levels of cortisol and other steroids in the body. This can have various effects on the body, including anti-inflammatory and immunosuppressive actions.

However, long-term use of carbenoxolone has been associated with serious side effects such as hypertension, hypokalemia (low potassium levels), and edema (fluid retention). Therefore, its use is generally limited to short-term treatment of gastric and duodenal ulcers.

Medical Definition: Carbenoxolone

A synthetic derivative of glycyrrhizin, used in the treatment of gastric and duodenal ulcers due to its ability to increase mucosal resistance and promote healing. It is an inhibitor of 11-beta-hydroxysteroid dehydrogenase, leading to increased levels of cortisol and other steroids in the body, with potential anti-inflammatory and immunosuppressive effects. However, long-term use is associated with serious side effects such as hypertension, hypokalemia, and edema.

Adherens junctions are specialized types of cell-cell contacts that play a crucial role in maintaining the integrity and stability of tissues. They are composed of transmembrane cadherin proteins, which connect to the actin cytoskeleton inside the cell through intracellular adaptor proteins such as catenins.

The cadherins on opposing cells interact with each other to form adhesive bonds that help to anchor the cells together and regulate various cellular processes, including cell growth, differentiation, and migration. Adherens junctions are essential for many physiological processes, such as embryonic development, wound healing, and tissue homeostasis, and their dysfunction has been implicated in a variety of diseases, including cancer and degenerative disorders.

Glycyrrhetinic acid is defined medically as a pentacyclic triterpenoid derived from glycyrrhizin, which is found in the root of licorice plants. It has been used in traditional medicine for its anti-inflammatory and expectorant properties.

Glycyrrhetinic acid works by inhibiting the enzyme 11-beta-hydroxysteroid dehydrogenase, which is responsible for converting cortisol to cortisone. This can lead to increased levels of cortisol in the body, which can have various effects, including lowering potassium levels and increasing sodium levels, leading to fluid retention and high blood pressure in some individuals.

In addition to its use in traditional medicine, glycyrrhetinic acid has been studied for its potential benefits in treating a variety of conditions, including cancer, HIV, and hepatitis. However, more research is needed to confirm these potential benefits and to fully understand the risks and side effects associated with its use.

Freeze fracturing is not a medical term itself, but it is a technique used in the field of electron microscopy, which is a type of imaging commonly used in scientific research and medical fields to visualize structures at a very small scale, such as cells and cellular components.

In freeze fracturing, a sample is rapidly frozen to preserve its structure and then fractured or split along a plane of weakness, often along the membrane of a cell. The freshly exposed surface is then shadowed with a thin layer of metal, such as platinum or gold, to create a replica of the surface. This replica can then be examined using an electron microscope to reveal details about the structure and organization of the sample at the molecular level.

Freeze fracturing is particularly useful for studying membrane structures, such as lipid bilayers and protein complexes, because it allows researchers to visualize these structures in their native state, without the need for staining or other chemical treatments that can alter or damage the samples.

Heptanol is not a medical term, but a chemical compound. It is more accurately referred to as n-heptanol or normal heptanol in chemistry. It is a primary alcohol with the molecular formula C7H16O. Heptanol is a colorless liquid that is used in the production of perfumes and flavors due to its mild, floral scent.

In medical contexts, heptanol might be encountered as a component of certain laboratory reagents or research tools, but it does not have specific medical applications or implications for human health.

The neuromuscular junction (NMJ) is the specialized synapse or chemical communication point, where the motor neuron's nerve terminal (presynaptic element) meets the muscle fiber's motor end plate (postsynaptic element). This junction plays a crucial role in controlling muscle contraction and relaxation.

At the NMJ, the neurotransmitter acetylcholine is released from the presynaptic nerve terminal into the synaptic cleft, following an action potential. Acetylcholine then binds to nicotinic acetylcholine receptors on the postsynaptic membrane of the muscle fiber, leading to the generation of an end-plate potential. If sufficient end-plate potentials are generated and summate, they will trigger an action potential in the muscle fiber, ultimately causing muscle contraction.

Dysfunction at the neuromuscular junction can result in various neuromuscular disorders, such as myasthenia gravis, where autoantibodies attack acetylcholine receptors, leading to muscle weakness and fatigue.

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.

Zonula Occludens-1 (ZO-1) protein is a tight junction (TJ) protein, which belongs to the membrane-associated guanylate kinase (MAGUK) family. It plays a crucial role in the formation and maintenance of tight junctions, which are complex structures that form a barrier between neighboring cells in epithelial and endothelial tissues.

Tight junctions are composed of several proteins, including transmembrane proteins and cytoplasmic plaque proteins. ZO-1 is one of the major cytoplasmic plaque proteins that interact with both transmembrane proteins (such as occludin and claudins) and other cytoskeletal proteins to form a network of protein interactions that maintain the integrity of tight junctions.

ZO-1 has multiple domains, including PDZ domains, SH3 domains, and a guanylate kinase-like domain, which allow it to interact with various binding partners. It is involved in regulating paracellular permeability, cell polarity, and signal transduction pathways that control cell proliferation, differentiation, and survival.

Mutations or dysfunction of ZO-1 protein have been implicated in several human diseases, including inflammatory bowel disease, cancer, and neurological disorders.

Electrical synapses, also known as gap junctions, are specialized types of connections between neurons that allow for the direct and rapid transmission of electrical signals from one cell to another. Unlike chemical synapses, which use neurotransmitters to transmit signals, electrical synapses contain channels called connexons that directly connect the cytoplasm of two adjacent cells. These channels are composed of proteins called connexins, which form a gap junction channel spanning the narrow gap between the pre- and postsynaptic membranes.

Electrical synapses allow for the rapid and synchronous transmission of action potentials between neurons, making them important for coordinating activity in neural circuits that require precise timing. They are also capable of bidirectional communication, allowing signals to be transmitted in both directions between connected cells. Additionally, electrical synapses can contribute to the generation and maintenance of synchronized oscillations in neural networks, which have been implicated in various cognitive processes such as attention, memory, and sensory processing.

Overall, electrical synapses play a crucial role in the functioning of the nervous system, particularly in situations where rapid and precise communication between neurons is necessary.

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

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

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

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

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

Isoquinolines are not a medical term per se, but a chemical classification. They refer to a class of organic compounds that consist of a benzene ring fused to a piperidine ring. This structure is similar to that of quinoline, but with the nitrogen atom located at a different position in the ring.

Isoquinolines have various biological activities and can be found in some natural products, including certain alkaloids. Some isoquinoline derivatives have been developed as drugs for the treatment of various conditions, such as cardiovascular diseases, neurological disorders, and cancer. However, specific medical definitions related to isoquinolines typically refer to the use or effects of these specific drugs rather than the broader class of compounds.

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).

The crystalline lens is a biconvex transparent structure in the eye that helps to refract (bend) light rays and focus them onto the retina. It is located behind the iris and pupil and is suspended by small fibers called zonules that connect it to the ciliary body. The lens can change its shape to accommodate and focus on objects at different distances, a process known as accommodation. With age, the lens may become cloudy or opaque, leading to cataracts.

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.

The esophagogastric junction (EGJ) is the region of the gastrointestinal tract where the esophagus (the tube that carries food from the mouth to the stomach) meets the stomach. It serves as a physiological sphincter, which helps control the direction of flow and prevent reflux of gastric contents back into the esophagus. The EGJ is also known as the gastroesophageal junction or cardia.

1-Octanol is a fatty alcohol with the chemical formula C8H17OH. It is a colorless oily liquid that is slightly soluble in water and miscible with most organic solvents. 1-Octanol is used as an intermediate in the synthesis of other chemicals, including pharmaceuticals, agrochemicals, and fragrances.

In medical terminology, 1-octanol may be used as a reference standard for measuring the partition coefficient of drugs between octanol and water, which can help predict their distribution and elimination in the body. This value is known as the octanol-water partition coefficient (Kow) and is an important parameter in pharmacokinetics and drug design.

Cadherins are a type of cell adhesion molecule that play a crucial role in the development and maintenance of intercellular junctions. They are transmembrane proteins that mediate calcium-dependent homophilic binding between adjacent cells, meaning that they bind to identical cadherin molecules on neighboring cells.

There are several types of cadherins, including classical cadherins, desmosomal cadherins, and protocadherins, each with distinct functions and localization in tissues. Classical cadherins, also known as type I cadherins, are the most well-studied and are essential for the formation of adherens junctions, which help to maintain cell-to-cell contact and tissue architecture.

Desmosomal cadherins, on the other hand, are critical for the formation and maintenance of desmosomes, which are specialized intercellular junctions that provide mechanical strength and stability to tissues. Protocadherins are a diverse family of cadherin-related proteins that have been implicated in various developmental processes, including neuronal connectivity and tissue patterning.

Mutations in cadherin genes have been associated with several human diseases, including cancer, neurological disorders, and heart defects. Therefore, understanding the structure, function, and regulation of cadherins is essential for elucidating their roles in health and disease.

"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.

Electric conductivity, also known as electrical conductance, is a measure of a material's ability to allow the flow of electric current through it. It is usually measured in units of Siemens per meter (S/m) or ohm-meters (Ω-m).

In medical terms, electric conductivity can refer to the body's ability to conduct electrical signals, which is important for various physiological processes such as nerve impulse transmission and muscle contraction. Abnormalities in electrical conductivity can be associated with various medical conditions, including neurological disorders and heart diseases.

For example, in electrocardiography (ECG), the electric conductivity of the heart is measured to assess its electrical activity and identify any abnormalities that may indicate heart disease. Similarly, in electromyography (EMG), the electric conductivity of muscles is measured to diagnose neuromuscular disorders.

Tight junction proteins are specialized proteins that play a crucial role in the formation and maintenance of tight junctions, which are intercellular structures that form a barrier to prevent the passage of molecules between cells. These proteins are found in the apical region of epithelial and endothelial cells and help to create a tight seal between adjacent cells.

Tight junction proteins can be classified into two major groups: transmembrane proteins and cytoplasmic plaque proteins. Transmembrane proteins, such as occludin and claudins, span the cell membrane and interact with each other to form the backbone of the tight junction. Cytoplasmic plaque proteins, such as zonula occludens (ZO) proteins, anchor the transmembrane proteins to the cytoskeleton and help to regulate their function.

Tight junction proteins are essential for maintaining the integrity of epithelial and endothelial barriers in various organs, including the gut, lungs, and blood-brain barrier. Dysfunction of these proteins has been implicated in a variety of diseases, such as inflammatory bowel disease, cancer, and neurological disorders.

Desmosomes are specialized intercellular junctions that provide strong adhesion between adjacent epithelial cells and help maintain the structural integrity and stability of tissues. They are composed of several proteins, including desmoplakin, plakoglobin, and cadherins, which form complex structures that anchor intermediate filaments (such as keratin) to the cell membrane. This creates a network of interconnected cells that can withstand mechanical stresses. Desmosomes are particularly abundant in tissues subjected to high levels of tension, such as the skin and heart.

Holliday junction resolvases are a type of enzyme that are involved in the process of genetic recombination. They are named after Robin Holliday, who first proposed the existence of a structure called a Holliday junction during genetic recombination.

A Holliday junction is a four-way DNA structure that forms when two DNA molecules exchange genetic material during recombination. The junction is held together by hydrogen bonds between complementary base pairs, and it can move along the DNA molecules through a process called branch migration.

Holliday junction resolvases are responsible for cleaving the DNA strands at the Holliday junction, resolving the structure into two separate DNA molecules. They do this by introducing nicks in the phosphodiester backbone of the DNA strands on either side of the junction and then joining the broken ends together. This results in the exchange of genetic material between the two original DNA molecules.

There are several different types of Holliday junction resolvases, including the bacterial RuvC and RecU enzymes, as well as the eukaryotic Flap endonuclease 1 (FEN1) and XPF/ERCC1 complexes. These enzymes have different specificities for cleaving the DNA strands at the Holliday junction, but they all play important roles in ensuring that genetic recombination occurs accurately and efficiently.

Electrophysiology is a branch of medicine that deals with the electrical activities of the body, particularly the heart. In a medical context, electrophysiology studies (EPS) are performed to assess abnormal heart rhythms (arrhythmias) and to evaluate the effectiveness of certain treatments, such as medication or pacemakers.

During an EPS, electrode catheters are inserted into the heart through blood vessels in the groin or neck. These catheters can record the electrical activity of the heart and stimulate it to help identify the source of the arrhythmia. The information gathered during the study can help doctors determine the best course of treatment for each patient.

In addition to cardiac electrophysiology, there are also other subspecialties within electrophysiology, such as neuromuscular electrophysiology, which deals with the electrical activity of the nervous system and muscles.

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

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.

Fluorescent dyes are substances that emit light upon excitation by absorbing light of a shorter wavelength. In a medical context, these dyes are often used in various diagnostic tests and procedures to highlight or mark certain structures or substances within the body. For example, fluorescent dyes may be used in imaging techniques such as fluorescence microscopy or fluorescence angiography to help visualize cells, tissues, or blood vessels. These dyes can also be used in flow cytometry to identify and sort specific types of cells. The choice of fluorescent dye depends on the specific application and the desired properties, such as excitation and emission spectra, quantum yield, and photostability.

Confocal microscopy is a powerful imaging technique used in medical and biological research to obtain high-resolution, contrast-rich images of thick samples. This super-resolution technology provides detailed visualization of cellular structures and processes at various depths within a specimen.

In confocal microscopy, a laser beam focused through a pinhole illuminates a small spot within the sample. The emitted fluorescence or reflected light from this spot is then collected by a detector, passing through a second pinhole that ensures only light from the focal plane reaches the detector. This process eliminates out-of-focus light, resulting in sharp images with improved contrast compared to conventional widefield microscopy.

By scanning the laser beam across the sample in a raster pattern and collecting fluorescence at each point, confocal microscopy generates optical sections of the specimen. These sections can be combined to create three-dimensional reconstructions, allowing researchers to study cellular architecture and interactions within complex tissues.

Confocal microscopy has numerous applications in medical research, including studying protein localization, tracking intracellular dynamics, analyzing cell morphology, and investigating disease mechanisms at the cellular level. Additionally, it is widely used in clinical settings for diagnostic purposes, such as analyzing skin lesions or detecting pathogens in patient samples.

Lindane is defined in medical terms as an agricultural and pharmaceutical compound that contains thegamma-isomer of hexachlorocyclohexane (γ-HCH). It has been used as a topical treatment for scabies and lice infestations, although its use is now limited due to concerns about toxicity and environmental persistence. Lindane works by disrupting the nervous system of insects, leading to paralysis and death. However, it can also have similar effects on mammals, including humans, at high doses or with prolonged exposure. Therefore, its use is restricted and alternatives are recommended for the treatment of scabies and lice.

Epithelial cells are types of cells that cover the outer surfaces of the body, line the inner surfaces of organs and glands, and form the lining of blood vessels and body cavities. They provide a protective barrier against the external environment, regulate the movement of materials between the internal and external environments, and are involved in the sense of touch, temperature, and pain. Epithelial cells can be squamous (flat and thin), cuboidal (square-shaped and of equal height), or columnar (tall and narrow) in shape and are classified based on their location and function.

Cell membrane permeability refers to the ability of various substances, such as molecules and ions, to pass through the cell membrane. The cell membrane, also known as the plasma membrane, is a thin, flexible barrier that surrounds all cells, controlling what enters and leaves the cell. Its primary function is to protect the cell's internal environment and maintain homeostasis.

The permeability of the cell membrane depends on its structure, which consists of a phospholipid bilayer interspersed with proteins. The hydrophilic (water-loving) heads of the phospholipids face outward, while the hydrophobic (water-fearing) tails face inward, creating a barrier that is generally impermeable to large, polar, or charged molecules.

However, specific proteins within the membrane, called channels and transporters, allow certain substances to cross the membrane. Channels are protein structures that span the membrane and provide a pore for ions or small uncharged molecules to pass through. Transporters, on the other hand, are proteins that bind to specific molecules and facilitate their movement across the membrane, often using energy in the form of ATP.

The permeability of the cell membrane can be influenced by various factors, such as temperature, pH, and the presence of certain chemicals or drugs. Changes in permeability can have significant consequences for the cell's function and survival, as they can disrupt ion balances, nutrient uptake, waste removal, and signal transduction.

Membrane potential is the electrical potential difference across a cell membrane, typically for excitable cells such as nerve and muscle cells. It is the difference in electric charge between the inside and outside of a cell, created by the selective permeability of the cell membrane to different ions. The resting membrane potential of a typical animal cell is around -70 mV, with the interior being negative relative to the exterior. This potential is generated and maintained by the active transport of ions across the membrane, primarily through the action of the sodium-potassium pump. Membrane potentials play a crucial role in many physiological processes, including the transmission of nerve impulses and the contraction of muscle cells.

Freeze etching is not a medical term per se, but it is a technique used in scientific research and analysis, including some medical fields such as microbiology and cell biology. Here's a brief explanation:

Freeze etching (also known as freeze-fracture replication) is a preparation technique for electron microscopy that allows the observation of biological specimens at high resolution. This method involves rapid freezing of a sample to preserve its natural structure, followed by fracturing it at low temperatures to expose internal surfaces. The exposed surface is then etched, or lightly bombarded with ions to remove thin layers of ice and reveal more detail. A layer of metal (usually platinum or gold) is then evaporated onto the surface at an oblique angle, creating a replica of the surface structure. This replica can be examined in a transmission electron microscope (TEM).

This technique is particularly useful for studying cell membranes and their associated structures, as it allows researchers to observe the distribution and organization of proteins and lipids within these membranes at high resolution.

The Fluorescent Antibody Technique (FAT) is a type of immunofluorescence assay used in laboratory medicine and pathology for the detection and localization of specific antigens or antibodies in tissues, cells, or microorganisms. In this technique, a fluorescein-labeled antibody is used to selectively bind to the target antigen or antibody, forming an immune complex. When excited by light of a specific wavelength, the fluorescein label emits light at a longer wavelength, typically visualized as green fluorescence under a fluorescence microscope.

The FAT is widely used in diagnostic microbiology for the identification and characterization of various bacteria, viruses, fungi, and parasites. It has also been applied in the diagnosis of autoimmune diseases and certain cancers by detecting specific antibodies or antigens in patient samples. The main advantage of FAT is its high sensitivity and specificity, allowing for accurate detection and differentiation of various pathogens and disease markers. However, it requires specialized equipment and trained personnel to perform and interpret the results.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

Ion channels are specialized transmembrane proteins that form hydrophilic pores or gaps in the lipid bilayer of cell membranes. They regulate the movement of ions (such as sodium, potassium, calcium, and chloride) across the cell membrane by allowing these charged particles to pass through selectively in response to various stimuli, including voltage changes, ligand binding, mechanical stress, or temperature changes. This ion movement is essential for many physiological processes, including electrical signaling, neurotransmission, muscle contraction, and maintenance of resting membrane potential. Ion channels can be categorized based on their activation mechanisms, ion selectivity, and structural features. Dysfunction of ion channels can lead to various diseases, making them important targets for drug development.

Fluorescence microscopy is a type of microscopy that uses fluorescent dyes or proteins to highlight and visualize specific components within a sample. In this technique, the sample is illuminated with high-energy light, typically ultraviolet (UV) or blue light, which excites the fluorescent molecules causing them to emit lower-energy, longer-wavelength light, usually visible light in the form of various colors. This emitted light is then collected by the microscope and detected to produce an image.

Fluorescence microscopy has several advantages over traditional brightfield microscopy, including the ability to visualize specific structures or molecules within a complex sample, increased sensitivity, and the potential for quantitative analysis. It is widely used in various fields of biology and medicine, such as cell biology, neuroscience, and pathology, to study the structure, function, and interactions of cells and proteins.

There are several types of fluorescence microscopy techniques, including widefield fluorescence microscopy, confocal microscopy, two-photon microscopy, and total internal reflection fluorescence (TIRF) microscopy, each with its own strengths and limitations. These techniques can provide valuable insights into the behavior of cells and proteins in health and disease.

Eye proteins, also known as ocular proteins, are specific proteins that are found within the eye and play crucial roles in maintaining proper eye function and health. These proteins can be found in various parts of the eye, including the cornea, iris, lens, retina, and other structures. They perform a wide range of functions, such as:

1. Structural support: Proteins like collagen and elastin provide strength and flexibility to the eye's tissues, enabling them to maintain their shape and withstand mechanical stress.
2. Light absorption and transmission: Proteins like opsins and crystallins are involved in capturing and transmitting light signals within the eye, which is essential for vision.
3. Protection against damage: Some eye proteins, such as antioxidant enzymes and heat shock proteins, help protect the eye from oxidative stress, UV radiation, and other environmental factors that can cause damage.
4. Regulation of eye growth and development: Various growth factors and signaling molecules, which are protein-based, contribute to the proper growth, differentiation, and maintenance of eye tissues during embryonic development and throughout adulthood.
5. Immune defense: Proteins involved in the immune response, such as complement components and immunoglobulins, help protect the eye from infection and inflammation.
6. Maintenance of transparency: Crystallin proteins in the lens maintain its transparency, allowing light to pass through unobstructed for clear vision.
7. Neuroprotection: Certain eye proteins, like brain-derived neurotrophic factor (BDNF), support the survival and function of neurons within the retina, helping to preserve vision.

Dysfunction or damage to these eye proteins can contribute to various eye disorders and diseases, such as cataracts, age-related macular degeneration, glaucoma, diabetic retinopathy, and others.

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

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

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).

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.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Biological factors are the aspects related to living organisms, including their genes, evolution, physiology, and anatomy. These factors can influence an individual's health status, susceptibility to diseases, and response to treatments. Biological factors can be inherited or acquired during one's lifetime and can interact with environmental factors to shape a person's overall health. Examples of biological factors include genetic predisposition, hormonal imbalances, infections, and chronic medical conditions.

Patch-clamp techniques are a group of electrophysiological methods used to study ion channels and other electrical properties of cells. These techniques were developed by Erwin Neher and Bert Sakmann, who were awarded the Nobel Prize in Physiology or Medicine in 1991 for their work. The basic principle of patch-clamp techniques involves creating a high resistance seal between a glass micropipette and the cell membrane, allowing for the measurement of current flowing through individual ion channels or groups of channels.

There are several different configurations of patch-clamp techniques, including:

1. Cell-attached configuration: In this configuration, the micropipette is attached to the outer surface of the cell membrane, and the current flowing across a single ion channel can be measured. This configuration allows for the study of the properties of individual channels in their native environment.
2. Whole-cell configuration: Here, the micropipette breaks through the cell membrane, creating a low resistance electrical connection between the pipette and the inside of the cell. This configuration allows for the measurement of the total current flowing across all ion channels in the cell membrane.
3. Inside-out configuration: In this configuration, the micropipette is pulled away from the cell after establishing a seal, resulting in the exposure of the inner surface of the cell membrane to the solution in the pipette. This configuration allows for the study of the properties of ion channels in isolation from other cellular components.
4. Outside-out configuration: Here, the micropipette is pulled away from the cell after establishing a seal, resulting in the exposure of the outer surface of the cell membrane to the solution in the pipette. This configuration allows for the study of the properties of ion channels in their native environment, but with the ability to control the composition of the extracellular solution.

Patch-clamp techniques have been instrumental in advancing our understanding of ion channel function and have contributed to numerous breakthroughs in neuroscience, pharmacology, and physiology.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

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.

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

Zonula Occludens-2 (ZO-2) protein is a tight junction protein, which belongs to the membrane-associated guanylate kinase homologs (MAGUKs) family. It plays a crucial role in the formation and maintenance of tight junctions, which are complex structures that form a barrier between neighboring cells in epithelial and endothelial tissues.

ZO-2 protein is localized to the cytoplasmic face of the tight junction and interacts with various proteins, including transmembrane proteins such as occludin and claudins, as well as other cytoskeletal proteins. It contains several functional domains that enable it to interact with these proteins, including PDZ (PSD-95/Dlg/ZO-1) domains, SH3 (Src homology 3) domains, and a guanylate kinase-like domain.

ZO-2 protein has been implicated in various cellular processes, including the regulation of tight junction permeability, cell signaling, and gene expression. Mutations in ZO-2 have been associated with several human diseases, including inflammatory bowel disease, cancer, and neurological disorders.

HeLa cells are a type of immortalized cell line used in scientific research. They are derived from a cancer that developed in the cervical tissue of Henrietta Lacks, an African-American woman, in 1951. After her death, cells taken from her tumor were found to be capable of continuous division and growth in a laboratory setting, making them an invaluable resource for medical research.

HeLa cells have been used in a wide range of scientific studies, including research on cancer, viruses, genetics, and drug development. They were the first human cell line to be successfully cloned and are able to grow rapidly in culture, doubling their population every 20-24 hours. This has made them an essential tool for many areas of biomedical research.

It is important to note that while HeLa cells have been instrumental in numerous scientific breakthroughs, the story of their origin raises ethical questions about informed consent and the use of human tissue in research.

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.

Lanthanum is not a medical term itself, but it is a chemical element with the symbol "La" and atomic number 57. It is a soft, ductile, silvery-white metal that belongs to the lanthanide series in the periodic table.

However, in medical contexts, lanthanum may be mentioned as a component of certain medications or medical devices. For example, lanthanum carbonate (trade name Fosrenol) is a medication used to treat hyperphosphatemia (elevated levels of phosphate in the blood) in patients with chronic kidney disease. Lanthanum carbonate works by binding to phosphate in the gastrointestinal tract, preventing its absorption into the bloodstream.

It is important to note that lanthanum compounds are not biologically active and do not have any specific medical effects on their own. Any medical uses of lanthanum are related to its physical or chemical properties, rather than its biological activity.

"Cruciform DNA" is a term used to describe a specific conformation or structure that a double-stranded DNA molecule can adopt. It is so-called because the structure resembles the shape of a cross or crucifix.

This conformation arises when two inverted repeats of DNA sequence are located close to each other on the same DNA molecule, such that they can pair up and form a stable secondary structure. This results in the formation of a hairpin loop at each end of the inverted repeat sequences, with the loops pointing towards each other and the intervening sequences forming two arms that cross in the middle.

Cruciform structures are important in various biological processes, including DNA replication, repair, and recombination. However, they can also pose challenges to these processes, as the crossing of the DNA strands can create topological constraints that must be resolved before replication or transcription can proceed.

It's worth noting that cruciform structures are not stable in solution and are usually only observed under specific conditions, such as when the DNA is supercoiled or when negative supercoiling is introduced through the action of enzymes like topoisomerases.

Epithelium is the tissue that covers the outer surface of the body, lines the internal cavities and organs, and forms various glands. It is composed of one or more layers of tightly packed cells that have a uniform shape and size, and rest on a basement membrane. Epithelial tissues are avascular, meaning they do not contain blood vessels, and are supplied with nutrients by diffusion from the underlying connective tissue.

Epithelial cells perform a variety of functions, including protection, secretion, absorption, excretion, and sensation. They can be classified based on their shape and the number of cell layers they contain. The main types of epithelium are:

1. Squamous epithelium: composed of flat, scalelike cells that fit together like tiles on a roof. It forms the lining of blood vessels, air sacs in the lungs, and the outermost layer of the skin.
2. Cuboidal epithelium: composed of cube-shaped cells with equal height and width. It is found in glands, tubules, and ducts.
3. Columnar epithelium: composed of tall, rectangular cells that are taller than they are wide. It lines the respiratory, digestive, and reproductive tracts.
4. Pseudostratified epithelium: appears stratified or layered but is actually made up of a single layer of cells that vary in height. The nuclei of these cells appear at different levels, giving the tissue a stratified appearance. It lines the respiratory and reproductive tracts.
5. Transitional epithelium: composed of several layers of cells that can stretch and change shape to accommodate changes in volume. It is found in the urinary bladder and ureters.

Epithelial tissue provides a barrier between the internal and external environments, protecting the body from physical, chemical, and biological damage. It also plays a crucial role in maintaining homeostasis by regulating the exchange of substances between the body and its environment.

I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.

If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.

Claudin-1 is a protein that is a member of the claudin family, which are important components of tight junctions in cells. Tight junctions are specialized structures that help to regulate the paracellular permeability of liquids and solutes between cells, and play a crucial role in maintaining cell polarity and tissue integrity. Claudin-1 is primarily expressed in epithelial and endothelial cells, where it helps to form tight junctions and regulate the movement of molecules across these barriers. Mutations in the gene that encodes claudin-1 have been associated with various human diseases, including skin disorders and cancer.

Ion channel gating refers to the process by which ion channels in cell membranes open and close in response to various stimuli, allowing ions such as sodium, potassium, and calcium to flow into or out of the cell. This movement of ions is crucial for many physiological processes, including the generation and transmission of electrical signals in nerve cells, muscle contraction, and the regulation of hormone secretion.

Ion channel gating can be regulated by various factors, including voltage changes across the membrane (voltage-gated channels), ligand binding (ligand-gated channels), mechanical stress (mechanosensitive channels), or other intracellular signals (second messenger-gated channels). The opening and closing of ion channels are highly regulated and coordinated processes that play a critical role in maintaining the proper functioning of cells and organ systems.

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.

Transfection is a term used in molecular biology that refers to the process of deliberately introducing foreign genetic material (DNA, RNA or artificial gene constructs) into cells. This is typically done using chemical or physical methods, such as lipofection or electroporation. Transfection is widely used in research and medical settings for various purposes, including studying gene function, producing proteins, developing gene therapies, and creating genetically modified organisms. It's important to note that transfection is different from transduction, which is the process of introducing genetic material into cells using viruses as vectors.

Electric impedance is a measure of opposition to the flow of alternating current (AC) in an electrical circuit or component, caused by both resistance (ohmic) and reactance (capacitive and inductive). It is expressed as a complex number, with the real part representing resistance and the imaginary part representing reactance. The unit of electric impedance is the ohm (Ω).

In the context of medical devices, electric impedance may be used to measure various physiological parameters, such as tissue conductivity or fluid composition. For example, bioelectrical impedance analysis (BIA) uses electrical impedance to estimate body composition, including fat mass and lean muscle mass. Similarly, electrical impedance tomography (EIT) is a medical imaging technique that uses electric impedance to create images of internal organs and tissues.

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.

Western blotting is a laboratory technique used in molecular biology to detect and quantify specific proteins in a mixture of many different proteins. This technique is commonly used to confirm the expression of a protein of interest, determine its size, and investigate its post-translational modifications. The name "Western" blotting distinguishes this technique from Southern blotting (for DNA) and Northern blotting (for RNA).

The Western blotting procedure involves several steps:

1. Protein extraction: The sample containing the proteins of interest is first extracted, often by breaking open cells or tissues and using a buffer to extract the proteins.
2. Separation of proteins by electrophoresis: The extracted proteins are then separated based on their size by loading them onto a polyacrylamide gel and running an electric current through the gel (a process called sodium dodecyl sulfate-polyacrylamide gel electrophoresis or SDS-PAGE). This separates the proteins according to their molecular weight, with smaller proteins migrating faster than larger ones.
3. Transfer of proteins to a membrane: After separation, the proteins are transferred from the gel onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric current in a process called blotting. This creates a replica of the protein pattern on the gel but now immobilized on the membrane for further analysis.
4. Blocking: The membrane is then blocked with a blocking agent, such as non-fat dry milk or bovine serum albumin (BSA), to prevent non-specific binding of antibodies in subsequent steps.
5. Primary antibody incubation: A primary antibody that specifically recognizes the protein of interest is added and allowed to bind to its target protein on the membrane. This step may be performed at room temperature or 4°C overnight, depending on the antibody's properties.
6. Washing: The membrane is washed with a buffer to remove unbound primary antibodies.
7. Secondary antibody incubation: A secondary antibody that recognizes the primary antibody (often coupled to an enzyme or fluorophore) is added and allowed to bind to the primary antibody. This step may involve using a horseradish peroxidase (HRP)-conjugated or alkaline phosphatase (AP)-conjugated secondary antibody, depending on the detection method used later.
8. Washing: The membrane is washed again to remove unbound secondary antibodies.
9. Detection: A detection reagent is added to visualize the protein of interest by detecting the signal generated from the enzyme-conjugated or fluorophore-conjugated secondary antibody. This can be done using chemiluminescent, colorimetric, or fluorescent methods.
10. Analysis: The resulting image is analyzed to determine the presence and quantity of the protein of interest in the sample.

Western blotting is a powerful technique for identifying and quantifying specific proteins within complex mixtures. It can be used to study protein expression, post-translational modifications, protein-protein interactions, and more. However, it requires careful optimization and validation to ensure accurate and reproducible results.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

Immunoelectron microscopy (IEM) is a specialized type of electron microscopy that combines the principles of immunochemistry and electron microscopy to detect and localize specific antigens within cells or tissues at the ultrastructural level. This technique allows for the visualization and identification of specific proteins, viruses, or other antigenic structures with a high degree of resolution and specificity.

In IEM, samples are first fixed, embedded, and sectioned to prepare them for electron microscopy. The sections are then treated with specific antibodies that have been labeled with electron-dense markers, such as gold particles or ferritin. These labeled antibodies bind to the target antigens in the sample, allowing for their visualization under an electron microscope.

There are several different methods of IEM, including pre-embedding and post-embedding techniques. Pre-embedding involves labeling the antigens before embedding the sample in resin, while post-embedding involves labeling the antigens after embedding. Post-embedding techniques are generally more commonly used because they allow for better preservation of ultrastructure and higher resolution.

IEM is a valuable tool in many areas of research, including virology, bacteriology, immunology, and cell biology. It can be used to study the structure and function of viruses, bacteria, and other microorganisms, as well as the distribution and localization of specific proteins and antigens within cells and tissues.

An action potential is a brief electrical signal that travels along the membrane of a nerve cell (neuron) or muscle cell. It is initiated by a rapid, localized change in the permeability of the cell membrane to specific ions, such as sodium and potassium, resulting in a rapid influx of sodium ions and a subsequent efflux of potassium ions. This ion movement causes a brief reversal of the electrical potential across the membrane, which is known as depolarization. The action potential then propagates along the cell membrane as a wave, allowing the electrical signal to be transmitted over long distances within the body. Action potentials play a crucial role in the communication and functioning of the nervous system and muscle tissue.

An oocyte, also known as an egg cell or female gamete, is a large specialized cell found in the ovary of female organisms. It contains half the number of chromosomes as a normal diploid cell, as it is the product of meiotic division. Oocytes are surrounded by follicle cells and are responsible for the production of female offspring upon fertilization with sperm. The term "oocyte" specifically refers to the immature egg cell before it reaches full maturity and is ready for fertilization, at which point it is referred to as an ovum or egg.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

The heart conduction system is a group of specialized cardiac muscle cells that generate and conduct electrical impulses to coordinate the contraction of the heart chambers. The main components of the heart conduction system include:

1. Sinoatrial (SA) node: Also known as the sinus node, it is located in the right atrium near the entrance of the superior vena cava and functions as the primary pacemaker of the heart. It sets the heart rate by generating electrical impulses at regular intervals.
2. Atrioventricular (AV) node: Located in the interatrial septum, near the opening of the coronary sinus, it serves as a relay station for electrical signals between the atria and ventricles. The AV node delays the transmission of impulses to allow the atria to contract before the ventricles.
3. Bundle of His: A bundle of specialized cardiac muscle fibers that conducts electrical impulses from the AV node to the ventricles. It divides into two main branches, the right and left bundle branches, which further divide into smaller Purkinje fibers.
4. Right and left bundle branches: These are extensions of the Bundle of His that transmit electrical impulses to the respective right and left ventricular myocardium. They consist of specialized conducting tissue with large diameters and minimal resistance, allowing for rapid conduction of electrical signals.
5. Purkinje fibers: Fine, branching fibers that arise from the bundle branches and spread throughout the ventricular myocardium. They are responsible for transmitting electrical impulses to the working cardiac muscle cells, triggering coordinated ventricular contraction.

In summary, the heart conduction system is a complex network of specialized muscle cells responsible for generating and conducting electrical signals that coordinate the contraction of the atria and ventricles, ensuring efficient blood flow throughout the body.

The myometrium is the middle and thickest layer of the uterine wall, composed mainly of smooth muscle cells. It is responsible for the strong contractions during labor and can also contribute to bleeding during menstruation or childbirth. The myometrium is able to stretch and expand to accommodate a growing fetus and then contract during labor to help push the baby out. It also plays a role in maintaining the structure and shape of the uterus, and in protecting the internal organs within the pelvic cavity.

"Newborn animals" refers to the very young offspring of animals that have recently been born. In medical terminology, newborns are often referred to as "neonates," and they are classified as such from birth until about 28 days of age. During this time period, newborn animals are particularly vulnerable and require close monitoring and care to ensure their survival and healthy development.

The specific needs of newborn animals can vary widely depending on the species, but generally, they require warmth, nutrition, hydration, and protection from harm. In many cases, newborns are unable to regulate their own body temperature or feed themselves, so they rely heavily on their mothers for care and support.

In medical settings, newborn animals may be examined and treated by veterinarians to ensure that they are healthy and receiving the care they need. This can include providing medical interventions such as feeding tubes, antibiotics, or other treatments as needed to address any health issues that arise. Overall, the care and support of newborn animals is an important aspect of animal medicine and conservation efforts.

Signal transduction is the process by which a cell converts an extracellular signal, such as a hormone or neurotransmitter, into an intracellular response. This involves a series of molecular events that transmit the signal from the cell surface to the interior of the cell, ultimately resulting in changes in gene expression, protein activity, or metabolism.

The process typically begins with the binding of the extracellular signal to a receptor located on the cell membrane. This binding event activates the receptor, which then triggers a cascade of intracellular signaling molecules, such as second messengers, protein kinases, and ion channels. These molecules amplify and propagate the signal, ultimately leading to the activation or inhibition of specific cellular responses.

Signal transduction pathways are highly regulated and can be modulated by various factors, including other signaling molecules, post-translational modifications, and feedback mechanisms. Dysregulation of these pathways has been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

Calcium signaling is the process by which cells regulate various functions through changes in intracellular calcium ion concentrations. Calcium ions (Ca^2+^) are crucial second messengers that play a critical role in many cellular processes, including muscle contraction, neurotransmitter release, gene expression, and programmed cell death (apoptosis).

Intracellular calcium levels are tightly regulated by a complex network of channels, pumps, and exchangers located on the plasma membrane and intracellular organelles such as the endoplasmic reticulum (ER) and mitochondria. These proteins control the influx, efflux, and storage of calcium ions within the cell.

Calcium signaling is initiated when an external signal, such as a hormone or neurotransmitter, binds to a specific receptor on the plasma membrane. This interaction triggers the opening of ion channels, allowing extracellular Ca^2+^ to flow into the cytoplasm. In some cases, this influx of calcium ions is sufficient to activate downstream targets directly. However, in most instances, the increase in intracellular Ca^2+^ serves as a trigger for the release of additional calcium from internal stores, such as the ER.

The release of calcium from the ER is mediated by ryanodine receptors (RyRs) and inositol trisphosphate receptors (IP3Rs), which are activated by specific second messengers generated in response to the initial external signal. The activation of these channels leads to a rapid increase in cytoplasmic Ca^2+^, creating a transient intracellular calcium signal known as a "calcium spark" or "calcium puff."

These localized increases in calcium concentration can then propagate throughout the cell as waves of elevated calcium, allowing for the spatial and temporal coordination of various cellular responses. The duration and amplitude of these calcium signals are finely tuned by the interplay between calcium-binding proteins, pumps, and exchangers, ensuring that appropriate responses are elicited in a controlled manner.

Dysregulation of intracellular calcium signaling has been implicated in numerous pathological conditions, including neurodegenerative diseases, cardiovascular disorders, and cancer. Therefore, understanding the molecular mechanisms governing calcium homeostasis and signaling is crucial for the development of novel therapeutic strategies targeting these diseases.

Cardiac myocytes are the muscle cells that make up the heart muscle, also known as the myocardium. These specialized cells are responsible for contracting and relaxing in a coordinated manner to pump blood throughout the body. They differ from skeletal muscle cells in several ways, including their ability to generate their own electrical impulses, which allows the heart to function as an independent rhythmical pump. Cardiac myocytes contain sarcomeres, the contractile units of the muscle, and are connected to each other by intercalated discs that help coordinate contraction and ensure the synchronous beating of the heart.

Phosphorylation is the process of adding a phosphate group (a molecule consisting of one phosphorus atom and four oxygen atoms) to a protein or other organic molecule, which is usually done by enzymes called kinases. This post-translational modification can change the function, localization, or activity of the target molecule, playing a crucial role in various cellular processes such as signal transduction, metabolism, and regulation of gene expression. Phosphorylation is reversible, and the removal of the phosphate group is facilitated by enzymes called phosphatases.

Synaptic transmission is the process by which a neuron communicates with another cell, such as another neuron or a muscle cell, across a junction called a synapse. It involves the release of neurotransmitters from the presynaptic terminal of the neuron, which then cross the synaptic cleft and bind to receptors on the postsynaptic cell, leading to changes in the electrical or chemical properties of the target cell. This process is critical for the transmission of signals within the nervous system and for controlling various physiological functions in the body.

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.

Phosphoproteins are proteins that have been post-translationally modified by the addition of a phosphate group (-PO3H2) onto specific amino acid residues, most commonly serine, threonine, or tyrosine. This process is known as phosphorylation and is mediated by enzymes called kinases. Phosphoproteins play crucial roles in various cellular processes such as signal transduction, cell cycle regulation, metabolism, and gene expression. The addition or removal of a phosphate group can activate or inhibit the function of a protein, thereby serving as a switch to control its activity. Phosphoproteins can be detected and quantified using techniques such as Western blotting, mass spectrometry, and immunofluorescence.

Desmoplakins are important proteins that play a crucial role in the structural integrity and function of certain types of cell-to-cell junctions called desmosomes. Desmosomes are specialized structures that connect adjacent cells in tissues that undergo significant mechanical stress, such as the skin, heart, and gut.

Desmoplakins are large proteins that are composed of several domains, including a plakin domain, which interacts with other desmosomal components, and a spectrin-like repeat domain, which binds to intermediate filaments. By linking desmosomes to the intermediate filament network, desmoplakins help to provide mechanical strength and stability to tissues.

Mutations in the genes that encode desmoplakins have been associated with several human genetic disorders, including arrhythmogenic right ventricular cardiomyopathy (ARVC), a heart condition characterized by abnormal heart rhythms and structural changes in the heart muscle, and epidermolysis bullosa simplex (EBS), a skin disorder characterized by blistering and fragility of the skin.

Alpha-catenin is a protein that plays a crucial role in cell adhesion and the maintenance of the cytoskeleton. It is a component of the cadherin-catenin complex, which is responsible for forming tight junctions between cells, known as adherens junctions. Alpha-catenin binds to beta-catenin, which in turn interacts with cadherins, transmembrane proteins that mediate cell-cell adhesion. This interaction helps to link the actin cytoskeleton to the cadherin-catenin complex, providing strength and stability to adherens junctions. Additionally, alpha-catenin has been implicated in various signaling pathways related to cell growth, differentiation, and migration.

Biotin is a water-soluble vitamin, also known as Vitamin B7 or Vitamin H. It is a cofactor for several enzymes involved in metabolism, particularly in the synthesis and breakdown of fatty acids, amino acids, and carbohydrates. Biotin plays a crucial role in maintaining healthy skin, hair, nails, nerves, and liver function. It is found in various foods such as nuts, seeds, whole grains, milk, and vegetables. Biotin deficiency is rare but can occur in people with malnutrition, alcoholism, pregnancy, or certain genetic disorders.

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.

Coloring agents, also known as food dyes or color additives, are substances that are added to foods, medications, and cosmetics to improve their appearance by giving them a specific color. These agents can be made from both synthetic and natural sources. They must be approved by regulatory agencies such as the U.S. Food and Drug Administration (FDA) before they can be used in products intended for human consumption.

Coloring agents are used for various reasons, including:

* To replace color lost during food processing or preparation
* To make foods more visually appealing
* To help consumers easily identify certain types of food
* To indicate the flavor of a product (e.g., fruit-flavored candies)

It's important to note that while coloring agents can enhance the appearance of products, they do not affect their taste or nutritional value. Some people may have allergic reactions to certain coloring agents, so it's essential to check product labels if you have any known allergies. Additionally, excessive consumption of some synthetic coloring agents has been linked to health concerns, so moderation is key.

The "bystander effect" is a social psychological phenomenon in which the presence of other people discourages an individual from intervening in an emergency situation. It is also known as bystander apathy or Genovese syndrome. This effect was named after the infamous murder of Kitty Genovese in 1964, where it was reported that dozens of witnesses heard her screams for help but did not call the police or intervene.

The bystander effect is thought to occur because individuals in a group may assume that someone else will take action, or they may feel uncertain about how to respond and hesitant to get involved. Additionally, the presence of other people can dilute an individual's sense of personal responsibility for taking action. The bystander effect has been demonstrated in numerous experiments and real-world situations, and it highlights the importance of encouraging individuals to take action and intervene in emergency situations, even when others are present.

Cell adhesion refers to the binding of cells to extracellular matrices or to other cells, a process that is fundamental to the development, function, and maintenance of multicellular organisms. Cell adhesion is mediated by various cell surface receptors, such as integrins, cadherins, and immunoglobulin-like cell adhesion molecules (Ig-CAMs), which interact with specific ligands in the extracellular environment. These interactions lead to the formation of specialized junctions, such as tight junctions, adherens junctions, and desmosomes, that help to maintain tissue architecture and regulate various cellular processes, including proliferation, differentiation, migration, and survival. Disruptions in cell adhesion can contribute to a variety of diseases, including cancer, inflammation, and degenerative disorders.

Fluorescence Recovery After Photobleaching (FRAP) is a microscopy technique used to study the mobility and diffusion of molecules in biological samples, particularly within living cells. This technique involves the use of an intense laser beam to photobleach (or permanently disable) the fluorescence of a specific region within a sample that has been labeled with a fluorescent probe or dye. The recovery of fluorescence in this bleached area is then monitored over time, as unbleached molecules from adjacent regions move into the bleached area through diffusion or active transport.

The rate and extent of fluorescence recovery can provide valuable information about the mobility, binding interactions, and dynamics of the labeled molecules within their native environment. FRAP is widely used in cell biology research to investigate various processes such as protein-protein interactions, membrane fluidity, organelle dynamics, and gene expression regulation.

Filipin is not a medical term itself, but it is the name given to a group of compounds that are used in medicine and research. Medically, Filipin is often referred to as Filipin III or Filipin stain, which is a fluorescent polyene antibiotic used in the study of lipids, particularly in diagnosing certain types of lipid storage diseases such as Niemann-Pick disease type C. The Filipin stain binds to unesterified cholesterol and forms complexes that exhibit blue fluorescence under ultraviolet light. This property is used to detect the accumulation of free cholesterol in various tissues and cells, which can be indicative of certain diseases or conditions.

Cell differentiation is the process by which a less specialized cell, or stem cell, becomes a more specialized cell type with specific functions and structures. This process involves changes in gene expression, which are regulated by various intracellular signaling pathways and transcription factors. Differentiation results in the development of distinct cell types that make up tissues and organs in multicellular organisms. It is a crucial aspect of embryonic development, tissue repair, and maintenance of homeostasis in the body.

Freeze substitution is a histological technique used to preserve the ultrastructure of biological samples, mainly at the electron microscopy level. This method is used to prevent the formation of ice crystals during the freezing process that can damage cellular structures. In freeze substitution, the frozen sample is placed in a chemical fixative at low temperatures, typically between -80°C to -90°C, and then gradually warmed up to room temperature. During this process, the fixative replaces the ice in the sample, preserving the native structure of the cells and their organelles. This technique is particularly useful for studying lipid-rich tissues and membrane structures that are sensitive to ice crystal formation during freezing.

"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.

Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.

Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

Neuromuscular junction diseases are a group of disorders that affect the functioning of the neuromuscular junction, which is the site where nerve impulses are transmitted to muscles. These diseases are characterized by muscle weakness and fatigue, and can be caused by various factors such as autoimmune disorders, genetic mutations, or toxins.

Examples of neuromuscular junction diseases include myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes (CMS), and botulism. Myasthenia gravis is an autoimmune disorder that causes the immune system to attack the receptors in the neuromuscular junction, leading to muscle weakness and fatigue. LEMS is a rare autoimmune disorder that affects the nerve endings at the neuromuscular junction, causing muscle weakness and decreased reflexes.

Congenital myasthenic syndromes are genetic disorders that affect the functioning of the neuromuscular junction from birth, leading to muscle weakness and fatigue. Botulism is a rare but serious condition caused by the ingestion of botulinum toxin, which can lead to paralysis of the muscles due to interference with nerve impulse transmission at the neuromuscular junction.

Treatment for neuromuscular junction diseases may include medications such as cholinesterase inhibitors, immunosuppressive drugs, or plasma exchange therapy, depending on the specific diagnosis and severity of the condition.

The crystalline lens in the eye is composed of three main parts: the capsule, the cortex, and the nucleus. The lens cortex is the outer layer of the lens, located between the capsule and the nucleus. It is made up of proteins and water, and its primary function is to help refract (bend) light rays as they pass through the eye, contributing to the focusing power of the eye.

The cortex is more flexible than the central nucleus, allowing it to change shape and adjust the focus of the eye for different distances. However, with age, the lens cortex can become less elastic, leading to presbyopia, a common age-related condition that affects the ability to focus on close objects. Additionally, changes in the lens cortex have been associated with cataracts, a clouding of the lens that can impair vision.

Immunoblotting, also known as western blotting, is a laboratory technique used in molecular biology and immunogenetics to detect and quantify specific proteins in a complex mixture. This technique combines the electrophoretic separation of proteins by gel electrophoresis with their detection using antibodies that recognize specific epitopes (protein fragments) on the target protein.

The process involves several steps: first, the protein sample is separated based on size through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Next, the separated proteins are transferred onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric field. The membrane is then blocked with a blocking agent to prevent non-specific binding of antibodies.

After blocking, the membrane is incubated with a primary antibody that specifically recognizes the target protein. Following this, the membrane is washed to remove unbound primary antibodies and then incubated with a secondary antibody conjugated to an enzyme such as horseradish peroxidase (HRP) or alkaline phosphatase (AP). The enzyme catalyzes a colorimetric or chemiluminescent reaction that allows for the detection of the target protein.

Immunoblotting is widely used in research and clinical settings to study protein expression, post-translational modifications, protein-protein interactions, and disease biomarkers. It provides high specificity and sensitivity, making it a valuable tool for identifying and quantifying proteins in various biological samples.

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.

A synapse is a structure in the nervous system that allows for the transmission of signals from one neuron (nerve cell) to another. It is the point where the axon terminal of one neuron meets the dendrite or cell body of another, and it is here that neurotransmitters are released and received. The synapse includes both the presynaptic and postsynaptic elements, as well as the cleft between them.

At the presynaptic side, an action potential travels down the axon and triggers the release of neurotransmitters into the synaptic cleft through exocytosis. These neurotransmitters then bind to receptors on the postsynaptic side, which can either excite or inhibit the receiving neuron. The strength of the signal between two neurons is determined by the number and efficiency of these synapses.

Synapses play a crucial role in the functioning of the nervous system, allowing for the integration and processing of information from various sources. They are also dynamic structures that can undergo changes in response to experience or injury, which has important implications for learning, memory, and recovery from neurological disorders.

Cytoskeletal proteins are a type of structural proteins that form the cytoskeleton, which is the internal framework of cells. The cytoskeleton provides shape, support, and structure to the cell, and plays important roles in cell division, intracellular transport, and maintenance of cell shape and integrity.

There are three main types of cytoskeletal proteins: actin filaments, intermediate filaments, and microtubules. Actin filaments are thin, rod-like structures that are involved in muscle contraction, cell motility, and cell division. Intermediate filaments are thicker than actin filaments and provide structural support to the cell. Microtubules are hollow tubes that are involved in intracellular transport, cell division, and maintenance of cell shape.

Cytoskeletal proteins are composed of different subunits that polymerize to form filamentous structures. These proteins can be dynamically assembled and disassembled, allowing cells to change their shape and move. Mutations in cytoskeletal proteins have been linked to various human diseases, including cancer, neurological disorders, and muscular dystrophies.

The seminiferous epithelium is a specialized type of epithelial tissue that lines the seminiferous tubules within the testes. It is composed of various cell types, including germ cells in different stages of development (spermatogonia, primary and secondary spermatocytes, spermatids) and supportive cells called Sertoli cells.

The primary function of the seminiferous epithelium is to support sperm production (spermatogenesis). The Sertoli cells provide structural support and nourishment to the developing germ cells, helping them to differentiate into mature spermatozoa (sperm). This process involves a series of complex cellular events, including mitosis, meiosis, and spermiogenesis.

In addition to its role in sperm production, the seminiferous epithelium also plays a crucial part in maintaining the blood-testis barrier, which separates the testicular environment from the systemic circulation. This barrier helps protect developing germ cells from potential immune attacks and maintains an optimal microenvironment for spermatogenesis.

The retina is the innermost, light-sensitive layer of tissue in the eye of many vertebrates and some cephalopods. It receives light that has been focused by the cornea and lens, converts it into neural signals, and sends these to the brain via the optic nerve. The retina contains several types of photoreceptor cells including rods (which handle vision in low light) and cones (which are active in bright light and are capable of color vision).

In medical terms, any pathological changes or diseases affecting the retinal structure and function can lead to visual impairment or blindness. Examples include age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinitis pigmentosa among others.

Scanning electron microscopy (SEM) is a type of electron microscopy that uses a focused beam of electrons to scan the surface of a sample and produce a high-resolution image. In SEM, a beam of electrons is scanned across the surface of a specimen, and secondary electrons are emitted from the sample due to interactions between the electrons and the atoms in the sample. These secondary electrons are then detected by a detector and used to create an image of the sample's surface topography. SEM can provide detailed images of the surface of a wide range of materials, including metals, polymers, ceramics, and biological samples. It is commonly used in materials science, biology, and electronics for the examination and analysis of surfaces at the micro- and nanoscale.

"Xenopus" is not a medical term, but it is a genus of highly invasive aquatic frogs native to sub-Saharan Africa. They are often used in scientific research, particularly in developmental biology and genetics. The most commonly studied species is Xenopus laevis, also known as the African clawed frog.

In a medical context, Xenopus might be mentioned when discussing their use in research or as a model organism to study various biological processes or diseases.

Sertoli cells, also known as sustentacular cells or nurse cells, are specialized cells in the seminiferous tubules of the testis in mammals. They play a crucial role in supporting and nurturing the development of sperm cells (spermatogenesis). Sertoli cells create a microenvironment within the seminiferous tubules that facilitates the differentiation, maturation, and survival of germ cells.

These cells have several essential functions:

1. Blood-testis barrier formation: Sertoli cells form tight junctions with each other, creating a physical barrier called the blood-testis barrier, which separates the seminiferous tubules into basal and adluminal compartments. This barrier protects the developing sperm cells from the immune system and provides an isolated environment for their maturation.
2. Nutrition and support: Sertoli cells provide essential nutrients and growth factors to germ cells, ensuring their proper development and survival. They also engulf and digest residual bodies, which are byproducts of spermatid differentiation.
3. Phagocytosis: Sertoli cells have phagocytic properties, allowing them to remove debris and dead cells within the seminiferous tubules.
4. Hormone metabolism: Sertoli cells express receptors for various hormones, such as follicle-stimulating hormone (FSH), testosterone, and estradiol. They play a role in regulating hormonal signaling within the testis by metabolizing these hormones or producing inhibins, which modulate FSH secretion from the pituitary gland.
5. Regulation of spermatogenesis: Sertoli cells produce and secrete various proteins and growth factors that influence germ cell development and proliferation. They also control the release of mature sperm cells into the epididymis through a process called spermiation.

Protein transport, in the context of cellular biology, refers to the process by which proteins are actively moved from one location to another within or between cells. This is a crucial mechanism for maintaining proper cell function and regulation.

Intracellular protein transport involves the movement of proteins within a single cell. Proteins can be transported across membranes (such as the nuclear envelope, endoplasmic reticulum, Golgi apparatus, or plasma membrane) via specialized transport systems like vesicles and transport channels.

Intercellular protein transport refers to the movement of proteins from one cell to another, often facilitated by exocytosis (release of proteins in vesicles) and endocytosis (uptake of extracellular substances via membrane-bound vesicles). This is essential for communication between cells, immune response, and other physiological processes.

It's important to note that any disruption in protein transport can lead to various diseases, including neurological disorders, cancer, and metabolic conditions.

In medical terms, the heart is a muscular organ located in the thoracic cavity that functions as a pump to circulate blood throughout the body. It's responsible for delivering oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the rest of the body. The heart's rhythmic contractions and relaxations are regulated by a complex electrical conduction system.

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... s Gap junction α (GJA) proteins GJA1, Cx43, gap junction alpha-1 protein GJA2, Cx38, gap junction alpha-2 ... gap junction beta-5 protein GJB6, Cx30, gap junction beta-6 protein GJB7, Cx25, gap junction beta-7 protein Gap junction γ (GJC ... gap junction gamma-1 protein GJC2, Cx47, gap junction gamma-2 protein GJC3, Cx29, gap junction gamma-3 protein Gap junction δ ( ... gap junction alpha-12 protein Gap junction β (GJB) proteins GJB1, Cx32, gap junction beta-1 protein GJB2, Cx26, gap junction ...
As gap junctions have a major role in regulating the homeostasis of the liver, an abnormal expression of gap junctions can be a ... The pathogenesis of gap junctions varies between diseases. For inflammatory bowel disease, a decrease in gap junction ... Gap junction modulation describes the functional manipulation of gap junctions, specialized channels that allow direct ... This coupling is done by gap junctions. Gap junctions permit the passive diffusion of materials-such as ions-across the ...
... anchoring junctions) Gap junctions (communicating junction) Tight junctions (occluding junctions) Invertebrates have several ... Communicating junctions, or gap junctions allow for direct chemical communication between adjacent cellular cytoplasm through ... gap) junctions. Cell junctions are also important in reducing stress placed upon cells. In plants, similar communication ... Gap junctions play vital roles in the human body, including their role in the uniform contractile of the heart muscle. They are ...
Electrical synapses are formed by gap junctions that allow molecules to directly pass between neurons, creating a cytoplasm-to- ... Goodenough, Daniel A. (2009). "Gap junctions". Cold Spring Harbor Perspectives in Biology. 1:a002576 (1): a002576. doi:10.1101/ ...
Gap junctions allow the action potential to be transferred from one cell to the next (they are said to electrically couple ... Kurtenbach S, Kurtenbach S, Zoidl G (2014). "Gap junction modulation and its implications for heart function". Frontiers in ... ISBN 978-0-912912-11-0. Goodenough, Daniel A.; Paul, David L. (2009-07-01). "Gap junctions". Cold Spring Harbor Perspectives in ... Severs, Nicholas J. (2002-12-01). "Gap junction remodeling in heart failure". Journal of Cardiac Failure. 8 (6 Suppl): S293-299 ...
"Entrez Gene: GJA4 gap junction protein, alpha 4, 37kDa". Winterhager E, Kidder GM (May 2015). Gap junction connexins in female ... Gap junction alpha-4 protein, also known as Connexin-37 or Cx37, is a protein that in humans is encoded by the GJA4 gene. This ... Van Camp G, Coucke P, Speleman F, Van Roy N, Beyer EC, Oostra BA, Willems PJ (November 1995). "The gene for human gap junction ... ISBN 978-1-934115-46-6. Beyer EC, Paul DL, Goodenough DA (July 1990). "Connexin family of gap junction proteins". The Journal ...
The epithelial-cell gap-junction network couples non-sensory epithelial cells, while the connective-tissue gap-junction network ... Gap-junction channels recycle potassium ions back to the endolymph after mechanotransduction in hair cells. Importantly, gap ... Gap-junction proteins, called connexins, expressed in the cochlea play an important role in auditory functioning. Mutations in ... Kikuchi, T.; Kimura, R. S.; Paul, D. L.; Takasaka, T.; Adams, J. C. (2000). "Gap junction systems in the mammalian cochlea". ...
Due to the direct connection between excitable cells in the form of gap junctions, an action potential can be transmitted ... Brink PR, Cronin K, Ramanan SV (August 1996). "Gap junctions in excitable cells". Journal of Bioenergetics and Biomembranes. 28 ... A special case of a chemical synapse is the neuromuscular junction, in which the axon of a motor neuron terminates on a muscle ... Muscle action potentials are provoked by the arrival of a pre-synaptic neuronal action potential at the neuromuscular junction ...
Gap junctions synchronize cell activation. The body of the cell between the processes first deposits enamel, which will become ...
This alloy range provides for the ability to have band gaps in the range 1.92-1.87 eV. The lower GaAs junction has a band gap ... In order to decrease this effect, a tunnel junction is used. It is simply a wide band gap, highly doped diode. The high doping ... Multi-junction (MJ) solar cells are solar cells with multiple p-n junctions made of different semiconductor materials. Each ... The J-V characteristic of the tunnel junction is very important because it explains why tunnel junctions can be used to have a ...
For the last 20 years before Warner began her research on gap junctions, embryologists had been working hard to prove that gap ... Warner, Anne (1992). "Gap junctions in development--a perspective". Semin. Cell Biol. 3 (1): 81-91. doi:10.1016/S1043-4682(10) ... After confirming the successful blocking of the gap junctions in the 8-cell-embryos, Warner continued to grow the embryos and ... After injecting the embryos with a specific antibody, which was said to have blocked the channels of gap junctions, Warner ...
Britz-Cunningham, S. H; Shah, M. M; Zuppan, C. W; Fletcher, W. H (1995). "Mutations of the Connexin43 gap-junction gene in ... Oviedo, N. J; Levin, M (2007). "Smedinx-11 is a planarian stem cell gap junction gene required for regeneration and homeostasis ... Bauer, R; Lehmann, C; Fuss, B; Eckardt, F; Hoch, M (2002). "The Drosophila gap junction channel gene innexin 2 controls foregut ... Levin, M; Mercola, M (1999). "Gap junction-mediated transfer of left-right patterning signals in the early chick blastoderm is ...
Gap junctions are critical for cardiac myocytes; mice and humans deficient in a particular gap junction protein have severe ... gap junctions in animals and plasmodesmas in plants. Gap junctions are made of connexins in vertebrates and innexins in ... Electrical synapses are electrically conductive gap junctions between neurons. ... A communicating junction links the intracellular compartments of two adjacent cells, allowing transit of relatively small ...
In heart muscle gap junctions function to coordinate the beating of the heart. Adding even further to their versatility gap ... gap, tight and tricellular junctions. Adherens, desmosomes, tight and tricellular junctions, serve structural roles. The ... Gap junctions can form intercellular links, effectively a tiny direct regulated "pipe" called a connexon pair between the ... Intercellular bridges are larger than gap junction ICCs so are able to allow the movement of not only small signaling molecules ...
Gap junctions have been demonstrated in rare circumstances as one coupling mechanism between ICC and smooth muscle cells. ... Are gap junctions required for intercellular coupling?". Experientia. 46 (10): 1002-5. doi:10.1007/BF01940654. PMID 2226711. ... Electron microscopic and dye coupling studies to date have confirmed gap junctions as the major coupling mechanisms between ...
Cadherin Gap junction Tight junction protein (disambiguation) Zonulin Adherens junction Bhat, Ajaz A.; Uppada, Srijayaprakash; ... The corresponding junctions that occur in invertebrates are septate junctions. Tight junctions are composed of a branching ... An Overview of the Tight Junction at Zonapse.Net Occludin in Focus at Zonapse.Net Tight+Junctions at the U.S. National Library ... They are understood to be the backbone of tight junctions and play a significant role in the tight junction's ability to seal ...
Gap junctions Desmosomes Adherens junctions Tight junctions Gap junctions bring the adjacent cells within 2 nanometers of each ... Bennett, M. V.; Barrio, L. C.; Bargiello, T. A.; Spray, D. C.; Hertzberg, E.; Sáez, J. C. (1 March 1991). "Gap junctions: new ... Desmosomes leave a gap of 30 nanometers between cells. Adherens junctions, also called zonula adherens, are multiprotein ... Similar to adherens junctions, the intracellular domains of tight junctions interact with different scaffold proteins, adapter ...
Gap junctions and edhf. Univ Wales Medicine July 2004: EP1435925 Gap junctions and EDHF. June 2003: US 20030105165 Gap ... and in particular on the role of gap junctions. He conducted research in three areas: endothelial control of arterial tone by ... junctions and endothelial-derived hyperpolarizing factor (edhf). University Of Wales College Of Medecine April 2003: WO 2003/ ...
Gap junctions are specialized channels located within the cell membrane of many animal cell types, which serve as gateways that ... Witkop Jr, C. J.; White, J. G.; Waring, G. O. (1982). "Hereditary mucoepithelial dysplasia, a disease of gap junction and ... Lampe, P.; Lau, A. F. (Dec 2000). "Regulation of gap junctions by phosphorylation of connexins". Archives of Biochemistry and ... The disorder is attributed to improper formation of desmosomes and gap junctions, which prevents proper cornification of the ...
The gap junctions also connect deeper layers of cells to the surface layer (osteocytes when surrounded by bone). This was ... The osteoblasts are also connected by gap junctions, small pores that connect osteoblasts, allowing the cells in one cohort to ... Doty SB (1981). "Morphological evidence of gap junctions between bone cells". Calcif. Tissue Int. 33 (5): 509-12. doi:10.1007/ ... Yellowley CE, Li Z, Zhou Z, Jacobs CR, Donahue HJ (February 2000). "Functional gap junctions between osteocytic and ...
... rather it gap junctions with adjacent astrocytes, providing secondary pathway to nearby oligodendrocytes. With direct gap ... 2009). "Impaired astrocytic gap junction coupling and potassium buffering in a mouse model of tuberous sclerosis complex." ... With impairment in gap junction coupling between astrocytes, myriad of abnormalities in potassium buffering occurs which ... The panglial syncytium is a large network of interconnected glial cells, which are extensively linked by gap junctions. The ...
Tight junctions Adherens junctions Desmosomes Hemidesmosomes Gap junctions Matter K, Balda MS (March 2003). "Signalling to and ... For the septate junctions in the vertebrates, they play some roles of tight junctions. Na+/K+ ATPase works for the function of ... Septate junctions are in a tight arrangement which is parallel to each other. For the septate junctions, several components are ... Septate junctions are intercellular junctions found in invertebrate epithelial cells, appearing as ladder-like structures under ...
Gap junction beta-5 protein (GJB5), also known as connexin-31.1 (Cx31.1), is a protein that in humans is encoded by the GJB5 ... Gap junctions are conduits that allow the direct cell-to-cell passage of small cytoplasmic molecules, including ions, metabolic ... Gap junction channels consist of connexin protein subunits, which are encoded by a multigene family. GRCh38: Ensembl release 89 ... "Entrez Gene: gap junction protein". Canova C, Hashibe M, Simonato L, et al. (2009). "Genetic associations of 115 polymorphisms ...
Gap junction delta-4 protein (GJD4), also known as connexin-40.1 (Cx40.1), is a protein that in humans is encoded by the GJD4 ... "Entrez Gene: gap junction protein". Söhl G, Nielsen PA, Eiberger J, Willecke K (2003). "Expression profiles of the novel human ... Each gap junction channel is formed by docking of 2 hemichannels, each of which contains 6 connexin subunits. GRCh38: Ensembl ... Connexins, such as GJD4, are involved in the formation of gap junctions, intercellular conduits that directly connect the ...
Gap junction delta-2 (GJD2), also known as connexin-36 (Cx36) or gap junction alpha-9 (GJA9), is a protein that in humans is ... "Entrez Gene: gap junction protein". White TW, Srinivas M, Ripps H, et al. (2002). "Virtual cloning, functional expression, and ... This gene is a member of the large family of connexins that are required for the formation of gap junctions. Six connexin ... 2001). "Identification and functional expression of HCx31.9, a novel gap junction gene". Cell Commun. Adhes. 8 (4-6): 173-8. ...
Gap junction beta-7 protein (GJB7), also known as connexin-25 (Cx25), is a protein that in humans is encoded by the GJB7 gene. ... "Entrez Gene: gap junction protein". Söhl G, Nielsen PA, Eiberger J, Willecke K (2003). "Expression profiles of the novel human ... Each gap junction channel is formed by docking of 2 hemichannels, each of which contains 6 connexin subunits. GRCh38: Ensembl ... Connexins, such as GJB7, are involved in the formation of gap junctions, intercellular conduits that directly connect the ...
Gap junction alpha-10 protein, also known as connexin-62 (Cx62), is a protein that in humans is encoded by the GJA10 gene. ... "Entrez Gene: gap junction protein". Söhl G, Nielsen PA, Eiberger J, Willecke K (2003). "Expression profiles of the novel human ... Each gap junction channel is formed by docking of 2 hemichannels, each of which contains 6 connexin subunits. ENSG00000288435 ... Connexins, such as GJA10, are involved in the formation of gap junctions, intercellular conduits that directly connect the ...
Gap junction gamma-2 (GJC2), also known as connexin-46.6 (Cx46.6) and connexin-47 (Cx47) and gap junction alpha-12 (GJA12), is ... This gene encodes a gap junction protein. Gap junction proteins are members of a large family of homologous connexins and ... "Entrez Gene: gap junction protein". Ostergaard P, Simpson MA, Brice G, et al. (2011). "Rapid identification of mutations in ... 2010). "Two novel gap junction protein alpha 12 gene mutations in two Chinese patients with Pelizaeus-Merzbacher-like disease ...
It has been demonstrated that miR-155 can be transferred through gap junctions from leukemic cells to healthy B cells and ... Nesmiyanov P, Strygin A, Tolkachev B, Kaplanov K, Dotsenko A, Strygina A (2016). "mIRNA-155 shuttling through gap junctions ...
... "gap junction" and "gap junction plaque" non-interchangeable as the area of the gap junction plaque may contain proteins other ... "gap junction" and "gap junction plaque" non-interchangeable. To summarize, in early literature the term "gap junction" referred ... Some headway on the in vivo composition of the gap junction plaque is being made using TEM FRIL. Gap junction modulation Gap ... A gap junction is less frequently called a nexus or macula communicans. There has been some confusion with gap junctions being ...
These potholes are massive and are located just past the Sywell Road/Moonshine Gap junction. Repair required as a matter of ... Huge potholes after Sywell Road/Moonshine Gap T junction. Show reporters name ...
myoendothelial gap junction. ODQ. 1H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one. PBS. phosphate-buffered saline. TRAM-34. 1-[(2 ... In a similar manner, putative gap junction block with carbenoxolone increased the pEC50 for ACh in arteries from obese, but not ... Up-regulation of distinct IKCa- and gap junction-mediated pathways at myoendothelial microdomain sites, key mechanisms for ... Obesity Up-Regulates Intermediate Conductance Calcium-Activated Potassium Channels and Myoendothelial Gap Junctions to Maintain ...
Doping GaP Core-Shell Nanowire pn-Junctions: A Study by Off-Axis Electron Holography. *Mark ... The doping process in GaP core-shell nanowire pn-junctions using different precursors is evaluated by mapping the nanowires ... The doping process in GaP core-shell nanowire pn-junctions using different precursors is evaluated by mapping the nanowires ... article{e5f94020-3e14-45d9-8515-a0790de8fade, abstract = {{The doping process in GaP core-shell nanowire pn-junctions using ...
... gap acceptance when either a car or motorcycle was approaching a junction. We used a QUEST adaptive staircase to estimate gap ... Comparing drivers gap acceptance for cars and motorcycles at junctions using an adaptive staircase methodology ... Gap Acceptance; Threshold; Junctions; Motorcycles; Look But Fail To See; Adaptive Staircase. ... gap acceptance for cars and motorcycles at junctions using an adaptive staircase methodology. Transportation Research Part F: ...
Gap junction and Protein export (Figure 2C).of muscle samples was performed utilizing the UHPLC-Q-TOFMS platform. A total of ... N signaling pathway," "Gap junction" and "Protein export" (Figure 2C).of. Post date. March 8, 2024. Post last updated date ... N signaling pathway," "Gap junction" and "Protein export" (Figure 2C).of muscle samples was performed utilizing the UHPLC-Q- ... DavidShorb on N signaling pathway, Gap junction and Protein export (Figure 2C).of muscle samples was performed utilizing ...
Biophysical properties of gap junctions between freshly dispersed pairs of mouse pancreatic beta cells. In: Biophysical journal ... Biophysical properties of gap junctions between freshly dispersed pairs of mouse pancreatic beta cells. Biophysical journal. ... Biophysical properties of gap junctions between freshly dispersed pairs of mouse pancreatic beta cells. / Pérez-Armendariz, M ... Pérez-Armendariz, M., Roy, C., Spray, D. C., & Bennett, M. V. (1991). Biophysical properties of gap junctions between freshly ...
Ca-mediated and independent effects of arachidonic acid on gap junctions and Ca-independent effects of oleic acid and halothane ...
Dive into the research topics of Vitamin D3regulates the formation and degradation of gap junctions in androgen-responsive ... Vitamin D3regulates the formation and degradation of gap junctions in androgen-responsive human prostate cancer cells. ...
... and reduced connexin43-positive gap junctions, but concomitant electrical pacing increases connexin43-positive gap junctions in ... and reduced connexin43-positive gap junctions, but concomitant electrical pacing increases connexin43-positive gap junctions in ... and reduced connexin43-positive gap junctions, but concomitant electrical pacing increases connexin43-positive gap junctions in ... and reduced connexin43-positive gap junctions, but concomitant electrical pacing increases connexin43-positive gap junctions in ...
Other designations: gap junction alpha-8 protein,gap junction protein, alpha 8, 50kDa Links: Homologene , Ensembl Genomic ... Gene GJA8 : gap junction protein, alpha 8, 50kDa in Oryctolagus cuniculus. See the equivalent entry at NCBI ... Description: gap junction protein, alpha 8, 50kDa Type of gene: protein-coding NCBI gene id: 100358270 ...
Gap junction diseases of the skin. Am J Med Genet C Semin Med Genet. 2004 Nov 15;131C(1):12-9. doi: 10.1002/ajmg.c.30030. ... This gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. Connexin ... Gap junctions made with connexin 26 transport potassium ions and certain small molecules. ... Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and ...
ATP release through connexin hemichannels and gap junction transfer of second messengers propagate Ca2+ signals across the ... ATP release through connexin hemichannels and gap junction transfer of second messengers propagate Ca2+ signals across the ... Lanthanum, a connexin hemichannel blocker that does not affect gap junction (GJ) channels when applied extracellularly, limited ...
BM = basement membrane; CLD = cytoplasmic lipid droplet; D = desmosome; FDA = fat-depleted adipocyte; GJ = gap junction; ME = ... BM = basement membrane; CLD = cytoplasmic lipid droplet; D = desmosome; FDA = fat-depleted adipocyte; GJ = gap junction; ME = ... Stage 2 (day 2 or 3 to day 8 after birth): The tight junction in the alveolar cell closes. Copious milk secretion begins. ...
Gap junction beta-2 protein. A [auth B],. B [auth A]. 226. Homo sapiens. Mutation(s): 3 Gene Names: GJB2. Membrane Entity: Yes ... An electrostatic mechanism for Ca(2+)-mediated regulation of gap junction channels.. Bennett, B.C., Purdy, M.D., Baker, K.A., ... Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states ... we determined the X-ray crystal structures of the human Cx26 gap junction channel with and without bound Ca(2+). The two ...
Gap junction diseases of the skin. Am J Med Genet C Semin Med Genet. 2004 Nov 15;131C(1):12-9. doi: 10.1002/ajmg.c.30030. ... This gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. Connexin ... Gap junctions made with connexin 26 transport potassium ions and certain small molecules. ... Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and ...
Gap junctions suppress electrical but not [Ca(2+)] heterogeneity in resistance arteries. Hald, B. O., Welsh, D. G., von ... Managing the complexity of communication: regulation of gap junctions by post-translational modification. Axelsen, L. N., Callø ... Less is more: minimal expression of myoendothelial gap junctions optimizes cell-cell communication in virtual arterioles.. Hald ...
Multidisciplinary research in toxicology of heavy metals; high throughput system for gap junctions. ...
... studies focusing on gap junctions were also conducted. Gap function is impaired due to the loss of zonula occludens (ZO)-1, ZO- ... Inhibition of PKC-δ blocked translocation from the cytosol to the membrane and restored the loss of gap junction proteins (95 ... another gap junction protein) expression (96). In summary, PKC-β is thought to be the most crucial PKC isoform that ... The role of PKC in specific gap junction proteins still needs further exploration. PKC is also promising for detecting ...
"Gap Junctions, High Frequency Oscillations, and Epilepsy?". 8:35 pm - 8:40 pm. Discussion. ...
Expression and functions of neuronal gap junctions. Nat. Rev. Neurosci. 6:191-200 ... Expression and functions of neuronal gap junctions. Nat. Rev. Neurosci. 6:191-200 ...
2007) UNC-1 regulates gap junctions important to locomotion in C. elegans. Curr Biol 17:1334-1339. ... A, At 5 mm [Ca2+]o, the amplitude of ePSCs at the neuromuscular junction was significantly smaller in worms expressing SLO-1(gf ... 2001) SLO-1 potassium channels control quantal content of neurotransmitter release at the C. elegans neuromuscular junction. ... Evoked postsynaptic currents (ePSCs) were recorded from the C. elegans neuromuscular junction (NMJ) as described previously ( ...
Gap junction (235) * Pathogenic Escherichia coli infection (235) Choose Multiple... Brands * TrueMAB (156) ...
Gap junction alpha-3 protein. 20. 1.34. 0. 1.29. 0.0034. 1.47. 0.0023. 1.21. 0.0022. ...
Our Lab is focused on gap junction-mediated intercellular communication. We study expression of gap junction proteins ( ...
Al-Mn/I/Al-Mn tunnel junctions show low sub-gap conductance and BCS-like characteristics. This material is thus of significant ...
Activating Connexin43 gap junctions primes adipose tissue for therapeutic intervention. Zhu Y, Li N, Huang M, Chen X, An YA, Li ...
gap junction A confocal micrograph of a human embryo, with some remaining sperm cells, about five days after fertilization. The ...
  • This study investigates the effect of chronic obesity on endothelium-dependent vasodilation and the relative contribution of nitric oxide (NO), calcium-activated potassium channels (K Ca ), and myoendothelial gap junctions (MEGJs) in the rat saphenous artery. (
  • Less is more: minimal expression of myoendothelial gap junctions optimizes cell-cell communication in virtual arterioles. (
  • By 1974 one of the major gap junction proteins was dubbed a "connexin", and six connexins were observed to form a channels called a "connexon", due to the connections connexon pairs made between cells. (
  • The term connexin was used to describe the gap junction proteins connecting two cells with pores. (
  • In vertebrates, gap junction hemichannels are primarily homo- or hetero-hexamers of connexin proteins. (
  • Before innexins and connexins were well characterized, the genes coding for connexin gap junction channels were classified in one of three groups, based on gene mapping and sequence similarity: A, B and C (for example, GJA1, GJC1). (
  • This gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. (
  • Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and signaling molecules between neighboring cells that are in contact with each other. (
  • Gap junctions made with connexin 26 transport potassium ions and certain small molecules. (
  • Lanthanum, a connexin hemichannel blocker that does not affect gap junction (GJ) channels when applied extracellularly, limited the propagation of Ca(2+) responses to cells adjacent to the photostimulated area. (
  • Repolarization-depolarization disturbances in BrS patients can be caused by genetic mutations, abnormal neural crest cell migration, low expression of connexin-43 gap junction protein, or connexome disturbances. (
  • Within a gap junction reside protein complexes, referred initially to as "globules", observed to connect one cell to another and also vesicles within a cell to the outer cell membrane. (
  • These components include among others the tight junction protein ZO-1 that holds the membranes close together, sodium channels, and aquaporin. (
  • The polypeptide (Mr approximate to 10,000) characteristic of trypsin-treated gap junction preparations is shown to be two distinct polypeptides, both derived from the Mr 28,000 protein. (
  • N signaling pathway," "Gap junction" and "Protein export" (Figure 2C).of muscle samples was performed utilizing the UHPLC-Q-TOFMS platform. (
  • Gap junctions are one of four broad categories of intercellular connections that form between a multitude of animal cell types. (
  • This has led to the idea that pannexins may never form intercellular junctions in the same way connexins and innexins do and so should not use the same hemi-channel/channel naming. (
  • At gap junctions, the intercellular space is between 2 and 4 nm and hemichannels in the membrane of each cell are aligned with one another. (
  • Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states such as cardiac arrhythmias, cancer and trauma. (
  • To explore the mechanism by which Ca(2+) blocks intercellular communication during tissue injury, we determined the X-ray crystal structures of the human Cx26 gap junction channel with and without bound Ca(2+). (
  • Our Lab is focused on gap junction-mediated intercellular communication. (
  • Two gap junction inhibitors, 18β-glycyrrhetinic acid and arachidonic acid, had no effect on zinc-induced cell death in low-confluence culture, where physical separation prevents gap junctions from forming. (
  • Ca-mediated and independent effects of arachidonic acid on gap junctions and Ca-independent effects of oleic acid and halothane. (
  • With increasing ability to sequence the DNA of organisms the complexity of the gap junction family of proteins increased. (
  • Invertebrate gap junctions comprise proteins from the innexin family. (
  • Others have presented evidence based on genetic sequencing and overall functioning in tissues that pannexins should still be considered part of the gap junction family of proteins despite structural differences in the way function is achieved. (
  • We study expression of gap junction proteins (connexins) under different environmental conditions in model cell lines (HeLa) also skeletal myoblast. (
  • 0.02).Conclusion Human mesenchymal stem cell transplantation increased cardiac sympathetic innervation and angiogenesis, but reduced gap junction after transplanted in the canine heart. (
  • Adjacent cardiac cells are connected by intercalated discs containing desmosomes and gap junctions. (
  • Up-regulation of distinct IK Ca - and gap junction-mediated pathways at myoendothelial microdomain sites, key mechanisms for endothelial-derived hyperpolarization-type activity, maintains endothelium-dependent vasodilation in diet-induced obese rat saphenous artery. (
  • Astrocytic gap junctions have been implicated in the regulation of cell viability. (
  • While more than 26 different connexins frequently populate gap junctions in various different tissues there are at least 12 other components that form the specialized area of membrane called the gap junction. (
  • Though differing in sequence to connexins, innexins are similar enough to connexins to state that innexins form gap junctions in vivo in the same way connexins do. (
  • Channel composition influences the function of gap junction channels and different connexins will not necessarily form heterotypic with all others. (
  • Gap junction channels formed from two identical hemichannels are called homotypic, while those with differing hemichannels are heterotypic. (
  • Gap junctions, strongly implicated as channels for direct cell-to-cell communication, have been isolated from rat liver in high yield and purity. (
  • Although gj recorded in these experiments would be expected to be provided by current flowing through only a few channels of the unitary conductance previously reported for other gap junctions, no unitary junctional currents were observed even during reversible suppression of gj by octanol. (
  • This result suggests either that the single channel conductance of gap junction channels between beta cells is smaller than in other tissues (less than 20 pS) or that the small mean conductance is due to transitions between open and closed states that are too rapid or too slow to be resolved. (
  • Ephapses are often studied in the context of electrically induced potentials propagated among groups of nerve cell membranes, even in the absence of gap junction communication, with no discrete subcellular structures known. (
  • The initial discovery of gap junctions in nerve cells lent credence to their function in transmission of electrical impulses. (
  • Experimental confirmation followed with molecules, ions and electrical impulses shown to pass through the connexons which proved to be a generalized regulated gate between cells in gap junctions. (
  • While an ephapse, like a gap junction, involves the transmission of electrical signals the two are different. (
  • Coupling between beta cells through gap junctions has been postulated as a principal mechanism of electrical synchronization of glucose-induced activity throughout the islet of Langerhans. (
  • In contrast, concomitant electrical pacing increased gap junction expression by paracrine action. (
  • The myocardium behaves as a functional syncytium because of electrical coupling action provided by gap junctions. (
  • Under some conditions, neurons near each other can communicate using electrical impulses across a gap junction. (
  • We aim to develop nanowire-perovskite tandem junction solar cells with high solar energy harvesting efficiency. (
  • Challenges are overcoming the barrier of single to tandem junction performance, control over materials composition and doping for designed p-i-n and tunneling diodes between materials in a tandem (multi) junction NW PV device, and limitations set by surface recombination leading to loss of carriers intended for carrying the current. (
  • Participants accepted significantly smaller (riskier) gaps in front of motorcycles than in front of cars, particularly in the high-fidelity simulator. (
  • high throughput system for gap junctions. (
  • We tested whether gap junction coupling between astrocytes plays an important role in modulating zinc toxicity in hippocampal astrocytes. (
  • These data suggest that gap junctions in hippocampal astrocytes provide a protective role against zinc toxicity. (
  • Role of gap junctions in adverse reproductive outcome. (
  • There has been some confusion with gap junctions being related to ephapses in the past. (
  • These potholes are massive and are located just past the Sywell Road/Moonshine Gap junction. (
  • In a similar manner, putative gap junction block with carbenoxolone increased the pEC 50 for ACh in arteries from obese, but not control, rats. (
  • Our main focus will be to combine efficient III-V nanowire devices with emerging hybrid materials to form nanostructured tandem junctions. (
  • The striking similarity of proteins present at the cytoplasmic face of tight junctions, adherens junctions and gap junctions and their possible role in gene transcription and cytoskeletal anchorage is highlighted. (
  • Three major types of intercellular junctions exist in vertebrates: tight junctions, adherens junctions, and gap junctions [ 11 ]. (
  • Occludin and claudin-5 are the fundamental transmembrane proteins in the formation of tight junctions and connect to the cytoskeleton through the ZO family [ 12 ]. (
  • Blocking gap junctions with 100 muM carbenoxolone or 18α-glycyrrhetinic acid further inhibited the endothelium-derived hyperpolarization (EDH-mediated response in females but not in males. (
  • In contrast to methylphenidate, the effects of modafinil were attenuated by the gap-junction inhibitor carbenoxolone. (
  • Carbenoxolone, a gap junction inhibitor, antagonized modafinil, but not methylphenidate potentiation of cocaine self-administration. (
  • Connexin 33 impairs gap junction functionality by accelerating connexin 43 gap junction plaque endocytosis. (
  • Conventional blockers of gap junctions and transfection of cells with dominant-negative constructs of connexin 43 (Cx43) and Cx43-specific antisense oligodeoxynucleotides (asODNs) all act to slow interkinetic nuclear movement. (
  • It is unclear how a shortage of connexin 43 at the cell surface affects the structure of gap junctions in the outermost layer of skin (epidermis), or how these changes result in the skin abnormalities characteristic of EKVP. (
  • Gap junctions formed with abnormal connexin 43 proteins are often permanently closed, preventing the transport of any molecules. (
  • Some mutations prevent connexin 43 proteins from traveling to the cell surface where they are needed to form gap junctions. (
  • Modafinil is known to facilitate electrotonic neuronal coupling by actions on gap junctions. (
  • The diverse functional roles and regulation of neuronal gap junctions in the retina. (
  • Gap junctions allow molecules to pass freely through them, and are important for cell communication. (
  • Gap junctions allow for the transport of nutrients, charged particles (ions), and other small molecules that carry necessary communication signals between cells. (
  • These irregularities could be reduced by blocking gap junction channels-pathways that link neighboring cells and allow for direct exchange of small molecules and thus may amplify harmful effects. (
  • Gap junctions: multifaceted regulators of embryonic cortical development. (
  • The myocardium behaves as a functional syncytium because of electrical coupling action provided by gap junctions. (
  • Why both Cx26 and Cx30 are needed to create functional gap junctions, however, has been something of a puzzle. (
  • Lin explained, "The problem is simply caused by not having enough protein remaining in the ear of these mutant mice to assemble gap junctions. (
  • Under pathological conditions, inflammatory mediators can compromise barrier function, which is correlated with active cytoskeletal remodelling and gap formation between adjacent endothelial cells [ 3 , 20 , 21 ]. (
  • We therefore concluded that the gamma irradiation-induced disruption of cellular junctions in HUVECs was through the inflammatory MAPK/NF- κ B signaling pathway. (
  • Aberrant expression and function of gap junctions during carcinogenesis. (
  • The result shows that gap junctions don't have to contain both Cx26 and Cx30 for normal hearing. (