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Mahvash Disease
Mahvash disease is an autosomal recessive, hereditary pancreatic neuroendocrine tumor syndrome. The genetic defect that causes Mahvash disease is biallelic inactivating mutations of the glucagon receptor gene (''GCGR''). Mahvash disease was discovered by American physician Run Yu and his colleagues in 2008. Mahvash disease is very rare. There have been over 10 cases of Mahvash disease described by the end of 2018. Mahvash disease occurs in both females and males. Mahvash disease is also called “glucagon cell hyperplasia and neoplasia” or “glucagon cell adenomatosis” by some authors but Mahvash disease is a distinct disease entity while the two alternative terms are mostly histological descriptions. Some patients with “glucagon cell hyperplasia and neoplasia” do not have glucagon receptor mutations. Signs and symptoms Most patients with Mahvash disease are diagnosed in adulthood. Patients with Mahvash disease usually present with vague abdominal discomfort. Imaging wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreatic Neuroendocrine Tumor
Pancreatic neuroendocrine tumours (PanNETs, PETs, or PNETs), often referred to as "islet cell tumours", or "pancreatic endocrine tumours" are neuroendocrine neoplasms that arise from cells of the endocrine (hormonal) and nervous system within the pancreas. PanNETs are a type of neuroendocrine tumor, representing about one-third of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Many PanNETs are benign, while some are malignant. Aggressive PanNET tumors have traditionally been termed "islet cell carcinoma". PanNETs are quite distinct from the usual form of pancreatic cancer, the majority of which are adenocarcinomas, which arises in the exocrine pancreas. Only 1 or 2% of clinically significant pancreas neoplasms are PanNETs. Types The majority of PanNETs are benign, while some are malignant. The World Health Organization (WHO) classification scheme places neuroendocrine tumors into three main categories, which emphasize the tumor grade rather than the anatomical ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Institutes Of Health
The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late 1880s and is now part of the United States Department of Health and Human Services. The majority of NIH facilities are located in Bethesda, Maryland, and other nearby suburbs of the Washington metropolitan area, with other primary facilities in the Research Triangle Park in North Carolina and smaller satellite facilities located around the United States. The NIH conducts its own scientific research through the NIH Intramural Research Program (IRP) and provides major biomedical research funding to non-NIH research facilities through its Extramural Research Program. , the IRP had 1,200 principal investigators and more than 4,000 postdoctoral fellows in basic, translational, and clinical research, being the largest biomedical research instit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucagon Receptor
The glucagon receptor is a 62 kDa protein that is activated by glucagon and is a member of the class B G-protein coupled family of receptors, coupled to G alpha i, Gs and to a lesser extent G alpha q. Stimulation of the receptor results in the activation of adenylate cyclase and phospholipase C and in increased levels of the secondary messengers intracellular cAMP and calcium. In humans, the glucagon receptor is encoded by the gene. Glucagon receptors are mainly expressed in liver and in kidney with lesser amounts found in heart, adipose tissue, spleen, thymus, adrenal glands, pancreas, cerebral cortex, and gastrointestinal tract. Signal transduction pathway A glucagon receptor, upon binding with the signaling molecule glucagon, initiates a signal transduction pathway that begins with the activation of adenylate cyclase, which in turn produces cyclic AMP (cAMP). Protein kinase A, whose activation is dependent on the increased levels of cAMP, is responsible for the ensuin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroendocrine Tumor
Neuroendocrine tumors (NETs) are neoplasms that arise from cells of the endocrine (hormonal) and nervous systems. They most commonly occur in the intestine, where they are often called carcinoid tumors, but they are also found in the pancreas, lung, and the rest of the body. Although there are many kinds of NETs, they are treated as a group of tissue because the cells of these neoplasms share common features, such as looking similar, having special secretory granules, and often producing biogenic amines and polypeptide hormones. Classification WHO The World Health Organization (WHO) classification scheme places neuroendocrine tumors into three main categories, which emphasize the tumor grade rather than the anatomical origin: * well-differentiated neuroendocrine tumours, further subdivided into tumors with benign and those with uncertain behavior * well-differentiated (low grade) neuroendocrine carcinomas with low-grade malignant behavior * poorly differentiated (high grade) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Islet
An islet is a very small, often unnamed island. Most definitions are not precise, but some suggest that an islet has little or no vegetation and cannot support human habitation. It may be made of rock, sand and/or hard coral; may be permanent or tidal (i.e. surfaced reef or seamount); and may exist in the sea, lakes, rivers or any other sizeable bodies of water. Definition As suggested by its origin ''islette'', an Old French diminutive of "isle", use of the term implies small size, but little attention is given to drawing an upper limit on its applicability. The World Landforms website says, "An islet landform is generally considered to be a rock or small island that has little vegetation and cannot sustain human habitation", and further that size may vary from a few square feet to several square miles, with no specific rule pertaining to size. Other terms * Ait (/eɪt/, like eight) or eyot (/aɪ(ə)t, eɪt/), a small island. It is especially used to refer to river i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microadenoma
Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas.Pituitary Tumors Treatment (PDQ®)–Health Professional Version NIH National Cancer Institute Pituitary adenomas represent from 10% to 25% of all intracranial neoplasia, neoplasms and the estimated prevalence, prevalence rate in the general population is approximately 17%. Non-invasive and non-secreting pituitary adenomas are considered to be Benign tumors, benign in the literal as well as the clinical sense; however a recent meta-analysis (Fernández-Balsells, ''et al.'' 2011) of available research has shown there are to date scant studies – of poor qual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Cell Hyperplasia
Alpha cell hyperplasia is defined as a specific (without similar change in other islet cells), diffuse (not limited to a particular part of pancreas), and overwhelming (many-fold) increase of the number of pancreatic alpha cells. The pancreatic islets normally contain 4 types of cells; the alpha cells produce and release glucagon, a hormone that regulates the metabolism of glucose and amino acids. Although first described in early 1990s, alpha cell hyperplasia had remained an esoteric topic until the mid-2010s. Based on the pathogenesis and clinical presentation, alpha cell hyperplasia can be divided into 3 types: reactive, nonfunctional, and functional. Reactive alpha cell hyperplasia Any means to inhibit normal glucagon signaling in any vertebrate animals tested so far (zebra fish, mice, monkeys, and humans) causes reactive alpha cell hyperplasia. There is a negative feedback loop linking the pancreatic alpha cells and the liver. When glucagon signaling is inhibited, the liv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucagon
Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a Glucagon (medication), medication to treat a number of health conditions. Its effect is opposite to that of insulin, which lowers extracellular glucose. It is produced from proglucagon, encoded by the ''GCG'' gene. The pancreas releases glucagon when the amount of glucose in the bloodstream is too low. Glucagon causes the liver to engage in glycogenolysis: converting stored glycogen into glucose, which is released into the bloodstream. High blood-glucose levels, on the other hand, stimulate the release of insulin. Insulin allows glucose to be taken up and used by insulin-dependent tissues. Thus, glucagon and insulin are part of a feedback system that keeps blood glucose levels stable. Glucagon increases energy expenditure and is elevated under conditions of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amino Acids
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha amino acids appear in the genetic code. Amino acids can be classified according to the locations of the core structural functional groups, as Alpha and beta carbon, alpha- , beta- , gamma- or delta- amino acids; other categories relate to Chemical polarity, polarity, ionization, and side chain group type (aliphatic, Open-chain compound, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acid '' residues'' form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling lif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperaminoacidemia
Hyperaminoacidemia refers to the condition of having an excess of amino acids in the bloodstream The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha .... There is evidence that hyperaminoacidemia increases protein synthesis and anabolism. References Amino acid metabolism disorders {{endocrine-disease-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Cell
Alpha cells (α cells) are endocrine cells that are found in the Islets of langerhans, Islets of Langerhans in the pancreas. Alpha cells secrete the peptide hormone glucagon in order to increase glucose levels in the blood stream. Discovery Islets of Langerhans were first discussed by Paul Langerhans in his medical thesis in 1869. This same year, Laguesse named them after Langerhans. At first, there was a lot of controversy about what the Islets were made of and what they did. It appeared that all of the cells were the same within the Islet, but were histologically distinct from acini cells. Laguesse discovered that the cells within the Islets of Langerhans contained granules that distinguished them from acini cells. He also determined that these granules were products of the metabolism of the cells in which they were contained. Michael Lane was the one to discover that alpha cells were histologically different than beta cells in 1907. Before the function of alpha cells was disco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Recessive Disorders
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosomes is collectively known as atDNA or auDNA. For example, humans have a diploid genome that usually contains 22 pairs of autosomes and one allosome pair (46 chromosomes total). The autosome pairs are labeled with numbers (1–22 in humans) roughly in order of their sizes in base pairs, while allosomes are labelled with their letters. By contrast, the allosome pair consists of two X chromosomes in females or one X and one Y chromosome in males. Unusual combinations of XYY, XXY, XXX, XXXX, XXXXX or XXYY, among other Salome combinations, are known to occur and usually cause developmental abnormalities. Autosomes still contain sexual determination genes even though they are not sex chromosomes. For example, the SRY gene on the Y chromosome e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
