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Aromatized
Aromatization is a chemical reaction in which an aromatic system is formed from a single nonaromatic precursor. Typically aromatization is achieved by dehydrogenation of existing cyclic compounds, illustrated by the conversion of cyclohexane into benzene. Aromatization includes the formation of heterocyclic systems. : Industrial practice Although not practiced under the name, aromatization is a cornerstone of oil refining. One of the major reforming reactions is the dehydrogenation of naphthenes into aromatics. The process, which is catalyzed by platinum, is exemplified in the conversion methylcyclohexane (a naphthene) into toluene (an aromatic). Dehydrocyclization converts paraffins (acyclic hydrocarbons) into aromatics. A related aromatization process includes dehydroisomerization of methylcyclopentane to benzene: : Biochemical processes : Aromatases are enzymes that aromatize rings within steroids. The specific conversions are testosterone to estradiol and androstenedione ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (chemistry), products, which usually have properties different from the reactants. Reactions often consist of a sequence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androstenedione
Androstenedione, or 4-androstenedione (abbreviated as A4 or Δ4-dione), also known as androst-4-ene-3,17-dione, is an endogenous weak androgen steroid hormone and intermediate in the biosynthesis of estrone and of testosterone from dehydroepiandrosterone (DHEA). It is closely related to androstenediol (androst-5-ene-3β,17β-diol). Biological function Androstenedione is a precursor of testosterone and other androgens, as well as of estrogens like estrone, in the body. In addition to functioning as an endogenous prohormone, androstenedione also has weak androgenic activity in its own right. Androstenedione has been found to possess some estrogenic activity, similarly to other DHEA metabolites. However, in contrast to androstenediol, its affinity for the estrogen receptors is very low, with less than 0.01% of the affinity of estradiol for both the ERα and ERβ. Adrenarche In children aged 6 to 8 years old, there is a rise in androstenedione secretion along with DHEA during adr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Competitive Inhibition
Competitive inhibition is interruption of a chemical pathway owing to one chemical substance inhibiting the effect of another by competing with it for binding or bonding. Any metabolic or chemical messenger system can potentially be affected by this principle, but several classes of competitive inhibition are especially important in biochemistry and medicine, including the competitive form of enzyme inhibition, the competitive form of receptor antagonism, the competitive form of antimetabolite activity, and the competitive form of poisoning (which can include any of the aforementioned types). Enzyme inhibition type In competitive inhibition of enzyme catalysis, binding of an inhibitor prevents binding of the target molecule of the enzyme, also known as the substrate. This is accomplished by blocking the binding site of the substrate – the active site – by some means. The Vmax indicates the maximum velocity of the reaction, while the Km is the amount of substrate needed to r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Letrozole
Letrozole, sold under the brand name Femara among others, is an aromatase inhibitor medication that is used in the treatment of breast cancer. It was patented in 1986 and approved for medical use in 1996. In 2020, it was the 257th most commonly prescribed medication in the United States, with more than 1million prescriptions. Medical uses Breast cancer Letrozole is approved by the United States Food and Drug Administration (FDA) for the treatment of local or metastatic breast cancer that is hormone receptor positive or has an unknown receptor status in postmenopausal women.Drugs.com: for letrozole. It is also used for ovarian cancer patients after they have completed chemotherapy. Comparison with tamoxifen Tamoxifen is also used to treat hormonally-responsive breast cancer, but it does so by interfering with the estrogen receptor. However, letrozole is effective only in post-menopausal women, in whom estrogen is produced predominantly in peripheral tissues (i.e. in adip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anastrozole
Anastrozole, sold under the brand name Arimidex among others, is a medication used in addition to other treatments for breast cancer. Specifically it is used for hormone receptor-positive breast cancer. It has also been used to prevent breast cancer in those at high risk. It is taken by mouth. Common side effects of anastrozole include hot flashes, altered mood, joint pain, and nausea. Severe side effects include an increased risk of heart disease and osteoporosis. Use during pregnancy may harm the baby. Anastrozole is in the aromatase-inhibiting family of medications. It works by blocking the production of estrogens in the body, and hence has antiestrogenic effects. Anastrozole was patented in 1987 and was approved for medical use in 1995. It is on the World Health Organization's List of Essential Medicines. Anastrozole is available as a generic medication. In 2020, it was the 180th most commonly prescribed medication in the United States, with more than 3million prescript ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exemestane
Exemestane, sold under the brand name Aromasin among others, is a medication used to treat breast cancer. It is a member of the class of antiestrogens known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs), and are called ER-positive. They may also be called estrogen-responsive, hormonally-responsive, or hormone-receptor-positive. Aromatase is an enzyme that synthesizes estrogen. Aromatase inhibitors block the synthesis of estrogen. This lowers the estrogen level, and slows the growth of cancers. Medical uses Exemestane is indicated for the adjuvant treatment of postmenopausal women with estrogen-receptor positive early breast cancer who have received two to three years of tamoxifen and are switched to it for completion of a total of five consecutive years of adjuvant hormonal therapy. US FDA approval was in October 1999. Exemestane is also indicated for the treatment of advanced breast cancer in postmenopausal wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aromatase Inhibitors
Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exogenously. They may also be used for chemoprevention in women at high risk for breast cancer. Aromatase is the enzyme that catalyzes a key aromatization step in the synthesis of estrogen. It converts the enone ring of androgen precursors such as testosterone, to a phenol, completing the synthesis of estrogen. As such, AIs are estrogen synthesis inhibitors. Because hormone-positive breast and ovarian cancers are dependent on estrogen for growth, AIs are taken to either block the production of estrogen or block the action of estrogen on receptors. Medical uses Cancer In contrast to premenopausal women, in whom most of the estrogen is produced in the ovaries, in postmenopausal women estrogen is mainly produced in peripheral tissues of the bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gynecomastia
Gynecomastia (also spelled gynaecomastia) is the abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Updated by Brent Wisse (10 November 2018) Gynecomastia can cause significant psychological distress or unease. Gynecomastia can be normal in newborn babies due to exposure to estrogen from the mother, in adolescents going through puberty, in older men over age 50, and/or in obese men. Most occurrences of gynecomastia do not require diagnostic tests. Gynecomastia may be caused by abnormal hormone changes, any condition that leads to an increase in the ratio of estrogens/androgens such as liver disease, kidney failure, thyroid disease and some non-breast tumors. Alcohol and some drugs can also cause breast enlargement. Other causes may include Klinefelter syndrome, metabolic dysfunction, or a natural decline in testosterone production. This may occur even if the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postmenopausal
Menopause, also known as the climacteric, is the time in women's lives when menstrual periods stop permanently, and they are no longer able to bear children. Menopause usually occurs between the age of 47 and 54. Medical professionals often define menopause as having occurred when a woman has not had any menstrual bleeding for a year. It may also be defined by a decrease in hormone production by the ovaries. In those who have had surgery to remove their uterus but still have functioning ovaries, menopause is not considered to have yet occurred. Following the removal of the uterus, symptoms typically occur earlier. 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 lighter or heavier in the amount of flow. During this time, women often experience hot flashes; these typically last from 30 seconds to ten minutes and may be associated with shivering, sweating, and reddening of the skin. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovarian Cancer
Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different cell types including epithelial cells, germ cells, and stromal cells. When these cells become abnormal, they have the ability to divide and form tumors. These cells can also invade or spread to other parts of the body. When this process begins, there may be no or only vague symptoms. Symptoms become more noticeable as the cancer progresses. These symptoms may include bloating, vaginal bleeding, pelvic pain, abdominal swelling, constipation, and loss of appetite, among others. Common areas to which the cancer may spread include the lining of the abdomen, lymph nodes, lungs, and liver. The risk of ovarian cancer increases with age. Most cases of ovarian cancer develop after menopause. It is also more common in women who have ovulated m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breast Cancer
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with distant spread of the disease, there may be bone pain, swollen lymph nodes, shortness of breath, or yellow skin. Risk factors for developing breast cancer include obesity, a lack of physical exercise, alcoholism, hormone replacement therapy during menopause, ionizing radiation, an early age at first menstruation, having children late in life or not at all, older age, having a prior history of breast cancer, and a family history of breast cancer. About 5–10% of cases are the result of a genetic predisposition inherited from a person's parents, including BRCA1 and BRCA2 among others. Breast cancer most commonly develops in cells from the lining of milk ducts and the lobules that supply these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumorogenesis
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cells are transformed into cancer cells. The process is characterized by changes at the cellular, genetic, and epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all tissues and under a variety of circumstances. Normally, the balance between proliferation and programmed cell death, in the form of apoptosis, is maintained to ensure the integrity of tissues and organs. According to the prevailing accepted theory of carcinogenesis, the somatic mutation theory, mutations in DNA and epimutations that lead to cancer disrupt these orderly processes by interfering with the programming regulating the processes, upsetting the normal balance between proliferation and cell death. This results in uncontrolled cell division and the evolution of those cells by natural selection in the body. Only certain mutations lead to cancer wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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