|
GM1
GM1 (monosialotetrahexosylganglioside) the "prototype" ganglioside, is a member of the ganglio series of gangliosides which contain one sialic acid residue. GM1 has important physiological properties and impacts neuronal plasticity and repair mechanisms, and the release of neurotrophins in the brain. Besides its function in the physiology of the brain, GM1 acts as the site of binding for both cholera toxin and E. coli heat-labile enterotoxin (Traveller's diarrhea). GM1 and inherited disease Galactosidases are enzymes that break down GM1, and the failure to remove GM1 results in GM1 gangliosidosis. GM1 gangliosidosis are inherited disorders that progressively destroy neurons in the brain and spinal cord as GM1 accumulates. Without treatment, this results in developmental decline and muscle weakness, eventually leading to severe retardation and death. GM1 and acquired disease Antibodies to GM1 are increased in Guillain–Barré syndrome, dementia and lupus but their function i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-ganglioside Antibodies
Antiganglioside antibodies that react to self-gangliosides are found in autoimmune neuropathies. These antibodies were first found to react with cerebellar cells. These antibodies show highest association with certain forms of Guillain–Barré syndrome. Antibodies to ganglioside subtypes Autoantigenic gangliosides that are currently known are GD3, GM1, GQ3 and GT1. Anti-GD3 Anti-GD3 antibodies have been found in association with specific forms of Guillain–Barré syndrome. In vivo studies of isolated anti-GM1 and GD3 antibodies indicate the antibodies can interfere with motor neuron function. Anti-GD1a antibodies were highly associated acute motor axonal neuropathy while high titers of anti-GM1 were more frequent indicating that GD1a possibly targets the axolemma and nodes of Ranvier most of the Ab+ patients had ''C. jejuni'' infections. Patients with Anti-GalNAc-GD1a antibodies were less common but had more severe disease (rapidly progressive, predominantly distal weakness). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholera Toxin
Cholera toxin (also known as choleragen, CTX, CTx and CT) is a potent enterotoxin produced by the bacterium Vibrio cholerae which causes severe watery diarrhea and dehydration that define cholera infections. The toxin is a member of the heat-labile enterotoxin family, and exists as an AB5 multimeric toxin with one enzymatically active A subunit and five receptor-binding B subunits that facilitate host cell entry. History The cholera toxin is the causative pathogenic agent of the ancient disease cholera, thought to have emerged in the Ganges Delta. For centuries the toxin remained confined to this region, but 19th-century globalisation spread it worldwide through the course of seven subsequent pandemics. When cholera arrived in London in 1832, its transmission was poorly understood, with many blaming miasma. Physician, John Snow (1813-1858) was an advocate of water contamination as the cause of its spread - famously ending an outbreak by removing a public water pump handle in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ganglioside
A ganglioside is a molecule composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (e.g. N-acetylneuraminic acid, ''N''-acetylneuraminic acid, NANA) linked on the sugar chain. NeuNAc, an acetylated derivative of the carbohydrate sialic acid, makes the head groups of gangliosides anionic at pH 7, which distinguishes them from globosides. The name ''ganglioside'' was first applied by the German scientist Ernst Klenk in 1942 to lipids newly isolated from ganglion, ganglion cells of the brain. More than 60 gangliosides are known, which differ from each other mainly in the position and number of N-Acetylneuraminic acid, NANA residue (chemistry), residues. It is a component of the cell plasma membrane that modulates cell signal transduction events, and appears to concentrate in lipid rafts. Recently, gangliosides have been found to be highly important molecules in immunology. Natural and semisynthetic gangliosides are considered possible therape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Adenosine Monophosphate
Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger, or cellular signal occurring within cells, that is important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal transduction in many different organisms, conveying the cAMP-dependent pathway. History Earl Sutherland of Vanderbilt University won a Nobel Prize in Physiology or Medicine in 1971 "for his discoveries concerning the mechanisms of the action of hormones", especially epinephrine, via second messengers (such as cyclic adenosine monophosphate, cyclic AMP). Synthesis The synthesis of cAMP is stimulated by trophic hormones that bind to receptors on the cell surface. cAMP levels reach maximal levels within minutes and decrease gradually over an hour in cultured cells. Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guillain–Barré Syndrome
Guillain–Barré syndrome (GBS) is a rapid-onset Paralysis, muscle weakness caused by the immune system damaging the peripheral nervous system. Typically, both sides of the body are involved, and the initial symptoms are changes in sensation or pain often in the back along with muscle weakness, beginning in the feet and hands, often spreading to the arms and upper body. The symptoms may develop over hours to a few weeks. During the acute phase, the disorder can be life-threatening, with about 15% of people developing respiratory system, respiratory muscle weakness requiring mechanical ventilation. Some are affected by dysautonomia, changes in the function of the autonomic nervous system, which can lead to dangerous abnormalities in heart rate and blood pressure. Although the cause is unknown, the underlying mechanism involves an autoimmune disorder in which the body's immune system mistakenly attacks the peripheral nerves and damages their myelin insulation. Sometimes this im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat-labile Enterotoxin
In molecular biology, the heat-labile enterotoxin family includes ''Escherichia coli'' heat-labile enterotoxin (Elt or LT) and cholera toxin (Ctx) secreted by ''Vibrio cholerae''. lt is so named because it is inactivated at high temperatures. Mechanism The A subunits are transported inside by the pentameric B subunits. It then acts by raising cAMP levels through ADP-ribosylation of the alpha-subunit of a Gs protein leading to the constitutive activation of adenylate cyclase. Elevated cAMP levels stimulate the activation of the CFTR channel thus stimulating secretion of chloride ions and water from the enterocyte into the gut lumen. This ionic imbalance causes watery diarrhea. In addition to its effects on chloride secretion, which involve the same steps as the effects of cholera toxin, Elt binds additional substrates: lipopolysaccharide on the surface of ''E. coli'' cells and A-type blood antigens. The importance of these binding events is not yet known. Structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multifocal Motor Neuropathy
Multifocal motor neuropathy (MMN) is a progressively worsening condition where muscles in the extremities gradually weaken. The disorder, a pure motor neuropathy syndrome, is sometimes mistaken for amyotrophic lateral sclerosis (ALS) because of the similarity in the clinical picture, especially if muscle fasciculations are present. MMN is thought to be autoimmune. It was first described in the mid-1980s. Unlike ALS, which affects both upper and lower motor neuron pathways, MMN involves only the lower motor neuron pathway, specifically, the peripheral nerves emanating from the lower motor neurons. Definitive diagnosis is often difficult, and many MMN patients labor for months or years under an ALS diagnosis before finally getting a determination of MMN. MMN usually involves very little pain; however, muscle cramps, spasms and twitches can cause pain for some people. MMN is not fatal, and does not diminish life expectancy. Many patients, once undergoing treatment, only experience ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterotoxigenic Escherichia Coli
Enterotoxigenic ''Escherichia coli'' (ETEC) is a type of ''Escherichia coli'' and one of the leading bacterial causes of diarrhea in the developing world, as well as the most common cause of travelers' diarrhea. Insufficient data exists, but conservative estimates suggest that each year, about 157,000 deaths occur, mostly in children, from ETEC. A number of pathogenic isolates are termed ETEC, but the main hallmarks of this type of bacterium are expression of one or more enterotoxins and presence of fimbriae used for attachment to host intestinal cells. The bacterium was identified by the Bradley Sack lab in Kolkata in 1968. Signs and symptoms Infection with ETEC can cause profuse, watery diarrhea with no blood or leukocytes and abdominal cramping. Fever, nausea with or without vomiting, chills, loss of appetite, headache, muscle aches and bloating can also occur, but are less common. Pathogenic factors Attachment ETEC use fimbrial colonization factor (CF) or coli surface (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGLT1
Sodium/glucose cotransporter 1 (SGLT1) also known as solute carrier family 5 member 1 is a protein in humans that is encoded by the gene which encodes the production of the SGLT1 protein to line the absorptive cells in the small intestine and the epithelial cells of the kidney tubules of the nephron for the purpose of glucose uptake into cells. Recently, it has been seen to have functions that can be considered as promising therapeutic target to treat diabetes and obesity. Through the use of the sodium glucose cotransporter 1 protein, cells are able to obtain glucose which is further utilized to make and store energy for the cell. Structure The sodium glucose cotransporter 1 is classified as an integral membrane protein that is made up of 14 alpha-helices constructed from the folding of 482-718 amino acid residues with both the N and C-terminal residing upon the extracellular side of the plasma membrane. It is hypothesized that the protein contains protein kinase A and pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biology), morphology) and death. These changes include Bleb (cell biology), blebbing, Plasmolysis, cell shrinkage, Karyorrhexis, nuclear fragmentation, Pyknosis, chromatin condensation, Apoptotic DNA fragmentation, DNA fragmentation, and mRNA decay. The average adult human loses 50 to 70 1,000,000,000, billion cells each day due to apoptosis. For the average human child between 8 and 14 years old, each day the approximate loss is 20 to 30 billion cells. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who is often regarded as one of the founders of modern pathology. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated digestion of cell components. In contrast, ''apoptosis'' is a naturally occurring programmed and targeted cause of cellular death. While apoptosis often provides beneficial effects to the organism, necrosis is almost always detrimental and can be fatal. Cellular death due to necrosis does not follow the apoptotic signal transduction pathway, but rather various receptors are activated and result in the loss of cell membrane integrity and an uncontrolled release of products of cell death into the extracellular space. This initiates an inflammatory response in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substantia Nigra
The substantia nigra (SN) is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. ''Substantia nigra'' is Latin for "black substance", reflecting the fact that parts of the substantia nigra appear darker than neighboring areas due to high levels of neuromelanin in dopaminergic neurons. Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta. Although the substantia nigra appears as a continuous band in brain sections, anatomical studies have found that it actually consists of two parts with very different connections and functions: the pars compacta (SNpc) and the pars reticulata (SNpr). The pars compacta serves mainly as a projection to the basal ganglia circuit, supplying the striatum with dopamine. The pars reticulata conveys signals from the basal ganglia to numerous other brain structures. Structure The substantia nigra, along with four other nuclei, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
