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Hif2a
Endothelial PAS domain-containing protein 1 (EPAS1, also known as hypoxia-inducible factor-2alpha (HIF-2α)) is a protein that is encoded by the ''EPAS1'' gene in mammals. It is a type of hypoxia-inducible factor, a group of transcription factors involved in the physiological response to oxygen concentration. The gene is active under hypoxic conditions. It is also important in the development of the heart, and for maintaining the catecholamine balance required for protection of the heart. Mutation often leads to neuroendocrine tumors. However, several characterized alleles of ''EPAS1'' contribute to high-altitude adaptation in humans. One such allele, which has been inherited from Denisovan archaic hominins, is known to confer increased athletic performance in some people, and has therefore been referred to as the "super athlete gene". Function The EPAS1 gene encodes one subunit of a transcription factor involved in the induction of genes regulated by oxygen, and which is indu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid resid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart Failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, and leg swelling. The shortness of breath may occur with exertion or while lying down, and may wake people up during the night. Chest pain, including angina, is not usually caused by heart failure, but may occur if the heart failure was caused by a heart attack. The severity of the heart failure is measured by the severity of symptoms during exercise. Other conditions that may have symptoms similar to heart failure include obesity, kidney failure, liver disease, anemia, and thyroid disease. Common causes of heart failure include coronary artery disease, heart attack, high blood pressure, atrial fibrillation, valvular heart disease, excessive alcohol consumption, infection, and cardiomyopathy. These cause heart failure by alteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythropoietin
Erythropoietin (; EPO), also known as erythropoetin, haematopoietin, or haemopoietin, is a glycoprotein cytokine secreted mainly by the kidneys in response to cellular hypoxia; it stimulates red blood cell production (erythropoiesis) in the bone marrow. Low levels of EPO (around 10 mU/mL) are constantly secreted in sufficient quantities to compensate for normal red blood cell turnover. Common causes of cellular hypoxia resulting in elevated levels of EPO (up to 10 000 mU/mL) include any anemia, and hypoxemia due to chronic lung disease. Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with the peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. Liver production predominates in the fetal and perinatal period; renal production predominates in adulthood. It is homologous with thrombopoietin. Exogenous erythropoietin, recombinant human erythropoietin (rhEPO) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheochromocytoma
Pheochromocytoma (PHEO or PCC) is a rare tumor of the adrenal medulla composed of chromaffin cells, also known as pheochromocytes. When a tumor composed of the same cells as a pheochromocytoma develops outside the adrenal gland, it is referred to as a paraganglioma. These neuroendocrine tumors are capable of producing and releasing massive amounts of catecholamines, metanephrines, or methoxytyramine, which result in the most common symptoms, including hypertension (high blood pressure), tachycardia (fast heart rate), and diaphoresis (sweating). However, not all of these tumors will secrete catecholamines. Those that do not are referred to as biochemically silent, and are predominantly located in the head and neck. While patients with biochemically silent disease will not develop the typical disease manifestations described above, the tumors grow and compress the surrounding structures of the head and neck, and can result in pulsatile tinnitus (ringing of the ear), hearing lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatostatinoma
Somatostatinomas are a tumor of the delta cells of the endocrine pancreas that produces somatostatin. Increased levels of somatostatin inhibit pancreatic hormones and gastrointestinal hormones. Thus, somatostatinomas are associated with mild diabetes mellitus (due to inhibition of insulin release), steatorrhoea and gallstones (due to inhibition of cholecystokinin release), and achlorhydria (due to inhibition of gastrin release). Somatostatinomas are commonly found in the head of pancreas. Only ten percent of somatostatinomas are functional tumours and 60–70% of tumours are malignant. Nearly two-thirds of patients with malignant somatostatinomas will present with metastatic disease. Pathophysiology In a normal subject, actions of somatostatin include: :*In the anterior pituitary gland, the effects of somatostatin are: ::* Inhibit the release of growth hormone, thus opposing the effects of growth hormone-releasing hormone (GHRH) ::* Inhibit the release of thyroid-stimulating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paragangliomas
A paraganglioma is a rare neuroendocrine neoplasm that may develop at various body sites (including the head, neck, thorax and abdomen). When the same type of tumor is found in the adrenal gland, they are referred to as a pheochromocytoma. They are rare tumors, with an overall estimated incidence of 1/300,000. There is no test that determines benign from malignant tumors; long-term follow-up is therefore recommended for all individuals with paraganglioma. Signs and symptoms Most paragangliomas are asymptomatic, present as a painless mass, or create symptoms such as hypertension, tachycardia, headache, and palpitations. While all contain neurosecretory granules, only in 1–3% of cases is secretion of hormones such as catecholamines abundant enough to be clinically significant; in that case manifestations often resemble those of pheochromocytomas (intra-medullary paraganglioma). Genetics About 75% of paragangliomas are sporadic; the remaining 25% are hereditary (and have an increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ghost Population
A ghost population is a population that has been inferred through using statistical techniques. Population studies In 2004, it was proposed that maximum likelihood or Bayesian approaches that estimate the migration rates and population sizes using coalescent theory can use datasets which contain a population that has no data. This is referred to as a "ghost population". The manipulation allows exploration in the effects of missing populations on the estimation of population sizes and migration rates between two specific populations. The biases of the inferred population parameters depend on the magnitude of the migration rate from the unknown populations. The technique for deriving ghost populations attracted criticism because ghost populations were the result of statistical models, along with their limitations. Population genetics In 2012, DNA analysis and statistical techniques were used to infer that a now-extinct human population in northern Eurasia had interbred with both th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tibetan Mastiff
The Tibetan Mastiff ( bo, འདོགས་ཁྱི, THL: , Wylie: ) * Nepali: * Mongolian: * Hindi/ Garhwali/ Kumaoni: * Kashmiri: * Ladakhi: * Dzongkha: is a large size Tibetan dog breed. Its double coat is medium to long, subject to climate, and found in a wide variety of colors, including solid black, black and tan, various shades of red (from pale gold to deep red) and bluish-gray (dilute black), and sometimes with white markings around neck, chest and legs. Name The term ''mastiff'' was assigned by the Europeans who first came to Tibet because that name was used to refer to nearly all large dog breeds in the West. Early Western visitors to Tibet misnamed several of its breeds, such as the Tibetan terrier, which is not a terrier, and the Tibetan spaniel, which is not a spaniel. A better name for the breed might be the ''Tibetan mountain dog'' or—to encompass the landrace breed throughout its range—the ''Himalayan mountain dog''. Description Appearance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Himalayan Wolf
The Himalayan wolf (''Canis lupus chanco'') is a canine of debated taxonomy. It is distinguished by its genetic markers, with mitochondrial DNA indicating that it is genetically basal to the Holarctic gray wolf, genetically the same wolf as the Tibetan and Mongolian wolf, and has an association with the African wolf (''Canis lupaster''). No striking morphological differences are seen between the wolves from the Himalayas and those from Tibet. The Himalayan wolf lineage can be found living in Ladakh in the Himalayas, the Tibetan Plateau, and the mountains of Central Asia predominantly above in elevation because it has adapted to a low-oxygen environment, compared with other wolves that are found only at lower elevations. Some authors have proposed the reclassification of this lineage as a separate species. In 2019, a workshop hosted by the IUCN/SSC Canid Specialist Group noted that the Himalayan wolf's distribution included the Himalayan range and the Tibetan Plateau. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaic Human Admixture With Modern Humans
There is evidence for interbreeding between archaic and modern humans during the Middle Paleolithic and early Upper Paleolithic. The interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins. In Eurasia, interbreeding between Neanderthals and Denisovans with modern humans took place several times. The introgression events into modern humans are estimated to have happened about 47,000–65,000 years ago with Neanderthals and about 44,000–54,000 years ago with Denisovans. Neanderthal-derived DNA has been found in the genomes of most or possibly all contemporary populations, varying noticeably by region. It accounts for 1–4% of modern genomes for people outside Sub-Saharan Africa, although estimates vary, and either none or possibly up to 0.3% — according to recent research — for those in Africa. It is highest in East Asians, intermediate in Europeans, and lower in Southeast Asians. Accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tibetan People
The Tibetan people (; ) are an East Asian ethnic group native to Tibet. Their current population is estimated to be around 6.7 million. In addition to the majority living in Tibet Autonomous Region of China, significant numbers of Tibetans live in the Chinese provinces of Gansu, Qinghai, Sichuan, and Yunnan, as well as in India, Nepal, and Bhutan. Tibetan languages belong to the Tibeto-Burman language group. The traditional or mythological explanation of the Tibetan people's origin is that they are the descendants of the human Pha Trelgen Changchup Sempa and rock ogress Ma Drag Sinmo. It is thought that most of the Tibeto-Burman speakers in Southwest China, including Tibetans, are direct descendants from the ancient Qiang people. Most Tibetans practice Tibetan Buddhism, although some observe the indigenous Bon religion and there is a small Muslim minority. Tibetan Buddhism influences Tibetan art, drama and architecture, while the harsh geography of Tibet has produ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homeostatic
In biology, homeostasis ( British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium and calcium ions, as well as that of the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Homeostasis is brought about by a natural resistance to change when already in the optimal conditions, and equilibrium is maintained by many regulatory mechanisms: it is thought to be the central motivation for all organic action. All homeostati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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