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Homovanillic Acid
Homovanillic acid (HVA) is a major catecholamine metabolite that is produced by a consecutive action of monoamine oxidase and catechol-O-methyltransferase on dopamine. Homovanillic acid is used as a reagent to detect oxidative enzymes, and is associated with dopamine levels in the brain. In psychiatry and neuroscience, brain and cerebrospinal fluid levels of HVA are measured as a marker of metabolic stress caused by 2-deoxy-D-glucose. HVA presence supports a diagnosis of neuroblastoma and malignant pheochromocytoma. Fasting plasma levels of HVA are known to be higher in females than in males. This does not seem to be influenced by adult hormonal changes, as the pattern is retained in the elderly and post-menopausal as well as transgender people according to their genetic sex, both before and during cross-sex hormone administration. Differences in HVA have also been correlated to tobacco Tobacco is the common name of several plants in the genus '' Nicotiana'' of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catecholamine
A catecholamine (; abbreviated CA), most typically a 3,4-dihydroxyphenethylamine, is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine. Catechol can be either a free molecule or a substituent of a larger molecule, where it represents a 1,2-dihydroxybenzene group. Catecholamines are derived from the amino acid tyrosine, which is derived from dietary sources as well as synthesis from phenylalanine. Catecholamines are water-soluble and are 50% bound to plasma proteins in circulation. Included among catecholamines are epinephrine (adrenaline), norepinephrine (noradrenaline), and dopamine. Release of the hormones epinephrine and norepinephrine from the adrenal medulla of the adrenal glands is part of the fight-or-flight response. Tyrosine is created from phenylalanine by hydroxylation by the enzyme phenylalanine hydroxylase. Tyrosine is also ingested directly from dietary prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurochemistry
Neurochemistry is the study of chemicals, including neurotransmitters and other molecules such as psychopharmaceuticals and neuropeptides, that control and influence the physiology of the nervous system. This particular field within neuroscience examines how neurochemicals influence the operation of neurons, synapses, and neural networks. Neurochemists analyze the biochemistry and molecular biology of organic compounds in the nervous system, and their roles in such neural processes including cortical plasticity, neurogenesis, and neural differentiation. History While neurochemistry as a recognized science is relatively new, the idea behind neurochemistry has been around since the 18th century. Originally, the brain had been thought to be a separate entity apart from the peripheral nervous system. Beginning in 1856, there was a string of research that refuted that idea. The chemical makeup of the brain was nearly identical to the makeup of the peripheral nervous system. The first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetic Acids
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Historically, vinegar was produced from the third century BC and was likely the first acid to be produced in large quantities. Acetic acid is the second simplest carboxylic acid (after formic acid). It is an important chemical reagent and industrial chemical across various fields, used primarily in the production of cellulose acetate for photographic film, polyvinyl acetate for wood glue, and synthetic fibres and fabrics. In households, diluted acetic acid is often used in descaling agents. In the food industry, acetic acid is controlled by the food additive code E260 as an acidity regulator and as a condiment. In biochemistry, the acetyl group, derived from acetic acid, is fundamental to all forms of life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanilloids
The vanilloids are compounds which possess a vanillyl group. They include vanillyl alcohol, vanillin, vanillic acid, acetovanillon, vanillylmandelic acid, homovanillic acid, capsaicin, etc. Isomers are the isovanilloids. : A number of vanilloids, most notably capsaicin, bind to the TRPV1, transient receptor potential vanilloid type 1 (TRPV1) receptor, an ion channel which naturally responds to noxious stimuli such as high temperatures and acidic pH. This action is responsible for the burning sensation experienced after eating capsicum, spicy peppers. Endogenously generated chemicals that trigger the TRPV1 channel of the vanilloids class are referred to as endovanilloids including anandamide, 20-hydroxyeicosatetraenoic acid (20-HETE), N-arachidonoyl dopamine (NADA) and N-oleoyl-dopamine (). Fatty-acid amide hydrolase 1, Fatty acid amide hydrolase (FAAH), is a crucial enzyme for endovanilloid, and the N-Acylethanolamine, ''N''-acylethanolamines (NAEs), catabolism at TRPV1, and oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homovanillyl Alcohol
Homovanillyl alcohol is a metabolite of hydroxytyrosol, which in turn is a metabolite of the neurotransmitter dopamine. See also * Homovanillic acid Homovanillic acid (HVA) is a major catecholamine metabolite that is produced by a consecutive action of monoamine oxidase and catechol-O-methyltransferase on dopamine. Homovanillic acid is used as a reagent to detect oxidative enzymes, and is ass ... References O-methylated phenylpropanoids Vanilloids {{Aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tobacco
Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the chief commercial crop is ''N. tabacum''. The more potent variant ''N. rustica'' is also used in some countries. Dried tobacco leaves are mainly used for smoking in cigarettes and cigars, as well as pipes and shishas. They can also be consumed as snuff, chewing tobacco, dipping tobacco, and snus. Tobacco contains the highly addictive stimulant alkaloid nicotine as well as harmala alkaloids. Tobacco use is a cause or risk factor for many deadly diseases, especially those affecting the heart, liver, and lungs, as well as many cancers. In 2008, the World Health Organization named tobacco use as the world's single greatest preventable cause of death. Etymology The English word 'tobacco' originates from the Spanish word ''taba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex Hormone
Sex hormones, also known as sex steroids, gonadocorticoids and gonadal steroids, are steroid hormones that interact with vertebrate steroid hormone receptors. The sex hormones include the androgens, estrogens, and progestogens. Their effects are mediated by slow genomic mechanisms through nuclear receptors as well as by fast nongenomic mechanisms through membrane-associated receptors and signaling cascades. Certain polypeptide hormones including the luteinizing hormone, follicle-stimulating hormone, and gonadotropin-releasing hormone – each associated with the gonadotropin axis – are usually not regarded as sex hormones, although they play major sex-related roles. Production Natural sex hormones are made by the gonads (ovaries or testicles), by adrenal glands, or by conversion from other sex steroids in other tissue such as liver or fat. Image:Steroidogenesis.svg Image:Biosinthesis of steroid hormones (simplified version).jpg Image:Biosinthesis of steroid hormones ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transgender People
A transgender (often shortened to trans) person has a gender identity different from that typically associated with the sex they were assigned at birth. The opposite of ''transgender'' is ''cisgender'', which describes persons whose gender identity matches their assigned sex. Often, transgender people desire medical assistance to medically transition from one sex to another; those who do may identify as transsexual.. "The term ''transsexual'' was introduced by Cauldwell (1949) and popularized by Harry Benjamin (1966) .. The term ''transgender'' was coined by John Oliven (1965) and popularized by various transgender people who pioneered the concept and practice of transgenderism. It is sometimes said that Virginia Prince (1976) popularized the term, but history shows that many transgender people advocated the use of this term much more than Prince." Referencing .. "The use of terminology by transsexual individuals to self-identify varies. As aforementioned, many transsexua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menopausal
Menopause, also known as the climacteric, is the time when menstrual periods permanently stop, marking the end of the reproductive stage for the female human. It typically occurs between the ages of 45 and 55, although the exact timing can vary. Menopause is usually a natural change related to a decrease in circulating blood estrogen levels. It can occur earlier in those who smoke tobacco. Other causes include surgery that removes both ovaries, some types of chemotherapy, or anything that leads to a decrease in hormone levels. At the physiological level, menopause happens because of a decrease in the ovaries' production of the hormones estrogen and progesterone. While typically not needed, measuring hormone levels in the blood or urine can confirm a diagnosis. Menopause is the opposite of menarche, the time when periods start. In the years before menopause, a woman's periods typically become irregular, which means that periods may be longer or shorter in duration, or be l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheochromocytoma
Pheochromocytoma is a rare tumor of the adrenal medulla composed of chromaffin cells and is part of the paraganglioma (PGL) family of tumors, being defined as an intra-adrenal PGL. These neuroendocrine tumors can be sympathetic, where they release catecholamines into the bloodstream which cause the most common symptoms, including hypertension (high blood pressure), tachycardia (fast heart rate), sweating, and headaches. Some PGLs may secrete little to no catecholamines, or only secrete paroxysmally (episodically), and other than secretions, PGLs can still become clinically relevant through other secretions or mass effect (most common with head and neck PGL). PGLs of the head and neck are typically parasympathetic and their sympathetic counterparts are predominantly located in the abdomen and pelvis, particularly concentrated at the organ of Zuckerkandl at the bifurcation of the aorta. Signs and symptoms The symptoms of a sympathetic pheochromocytoma are related to sympathetic n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroblastoma
Neuroblastoma (NB) is a type of cancer that forms in certain types of nerve tissue. It most frequently starts from one of the adrenal glands but can also develop in the head, neck, chest, abdomen, or Vertebral column, spine. Symptoms may include bone pain, a lump in the abdomen, neck, or chest, or a painless bluish lump under the skin. Typically, neuroblastoma occurs due to a genetic mutation occurring in the first trimester of pregnancy. Rarely, it may be due to a mutation heredity, inherited. Environmental factors have not been found to be involved. Diagnosis is based on a tissue biopsy. Occasionally, it may be found in a baby by ultrasound during pregnancy. At diagnosis, the cancer has usually already Metastasis, spread. The cancer is divided into low-, intermediate-, and high-risk groups based on a child's age, cancer stage, and what the cancer looks like. Treatment and outcomes depends on the risk group a person is in. Treatments may include observation, surgery, radiatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
