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Hongdoushans
Taxanes are a class of diterpenes. They were originally identified from plants of the genus ''Taxus'' (yews), and feature a taxadiene core. Paclitaxel (Taxol) and docetaxel (Taxotere) are widely used as chemotherapy agents. Cabazitaxel was FDA approved to treat hormone-refractory prostate cancer. Taxanes present difficulties in formulation as medicines because they are poorly soluble in water. Production As their name suggests, taxanes were first derived from natural sources, but some have been semisynthesized. Paclitaxel was originally derived from the Pacific yew tree. Taxanes are difficult to synthesize because of their numerous chiral centres—taxol has 11 of these. Recently, the presence of taxanes in the shells and leaves of ''Corylus avellana'' (the common hazel plant) has been reported. Mechanism of action The principal mechanism of action of the taxane class of drugs is the disruption of microtubule function. Microtubules are essential to cell division, and taxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxuspine
Taxanes are a class of diterpenes. They were originally identified from plants of the genus ''Taxus'' (yews), and feature a taxadiene core. Paclitaxel (Taxol) and docetaxel (Taxotere) are widely used as chemotherapy agents. Cabazitaxel was FDA approved to treat hormone-refractory prostate cancer. Taxanes present difficulties in formulation as medicines because they are poorly soluble in water. Production As their name suggests, taxanes were first derived from natural sources, but some have been semisynthesized. Paclitaxel was originally derived from the Pacific yew tree. Taxanes are difficult to synthesize because of their numerous chiral centres—taxol has 11 of these. Recently, the presence of taxanes in the shells and leaves of ''Corylus avellana'' (the common hazel plant) has been reported. Mechanism of action The principal mechanism of action of the taxane class of drugs is the disruption of microtubule function. Microtubules are essential to cell division, and taxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Union Of Pure And Applied Chemistry
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is a member of the International Science Council (ISC). IUPAC is registered in Zürich, Switzerland, and the administrative office, known as the "IUPAC Secretariat", is in Research Triangle Park, North Carolina, United States. This administrative office is headed by IUPAC's executive director, currently Lynn Soby. IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry. Its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, or other bodies representing chemists. There are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPAC's Inter-divisional Committee on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corylus Avellana
''Corylus avellana'', the common hazel, is a species of flowering plant in the birch family Betulaceae. It is native to Europe and western Asia. It is an important component of the hedgerows that were the traditional field boundaries in lowland England. The wood was traditionally grown as coppice, the poles cut being used for wattle-and-daub building and agricultural fencing. Common hazel is cultivated for its nuts. The name hazelnut applies to the nuts of any species in the genus ''Corylus'', but in commercial settings a hazelnut is usually that of ''C. avellana''. This hazelnut or cob nut, the kernel of the seed, is edible and used raw or roasted, or ground into a paste. The cob is round, compared with the longer filbert nut. Description Common hazel is typically a shrub reaching tall, but can reach . The leaves are deciduous, rounded, long and across, softly hairy on both surfaces, and with a double-serrate margin. The flowers are produced very early in spring, before ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxoid
Taxoids are a class of derivatives from taxol, that is, paclitaxel. They were developed for their anticancer chemotherapeutic properties. Taxoids are usually treated as synonymous with taxanes; for example, a major medical dictionary defines the two terms with the same definition phrasing, and in another the phrasing varies slightly but conveys nearly identical meaning. Taxoids are chemically taxane-derived diterpenoids, which do occur in nature, in the genera ''Taxus'' and ''Austrotaxus'' of yew trees. The taxoids class and the taxanes class both include paclitaxel (trade names Taxol, Abraxane, Onxol, Nov-Onxol) and docetaxel Docetaxel (DTX or DXL), sold under the brand name Taxotere among others, is a chemotherapy medication used to treat a number of types of cancer. This includes breast cancer, head and neck cancer, stomach cancer, prostate cancer and non-small-cell ... (trade names Taxotere, Docecad). References Mitotic inhibitors {{antineoplastic-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synonym
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all synonyms of one another: they are ''synonymous''. The standard test for synonymy is substitution: one form can be replaced by another in a sentence without changing its meaning. Words are considered synonymous in only one particular sense: for example, ''long'' and ''extended'' in the context ''long time'' or ''extended time'' are synonymous, but ''long'' cannot be used in the phrase ''extended family''. Synonyms with exactly the same meaning share a seme or denotational sememe, whereas those with inexactly similar meanings share a broader denotational or connotational sememe and thus overlap within a semantic field. The former are sometimes called cognitive synonyms and the latter, near-synonyms, plesionyms or poecilonyms. Lexicograph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxus Wallichiana
''Taxus wallichiana'', the Himalayan yew, is a species of yew, native to the Himalaya and parts of south-east Asia. The species has a variety of uses in traditional medicine. It is currently classified as endangered by the IUCN. Distribution and habitat The species favours a reasonably wide range of habitats, growing in montane, temperate, warm temperate, and tropical submontane to high montane forests which may be deciduous, evergreen, or of mixed character. In forests, it tends to present as a low canopy tree; in open situations it usually forms a large, broadly spreading shrub. Elevation ranges from 900 m to 3,700 m. Growth It is a medium-sized evergreen coniferous tree growing to 10 m tall, similar to ''Taxus baccata'' and sometimes treated as a subspecies of it. The shoots are green at first, becoming brown after three or four years. The leaves are thin, flat, slightly falcate (sickle-shaped), 1.5–2.7 cm long and 2 mm broad, with a softly mucronate apex; they ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiosensitivity
Radiosensitivity is the relative susceptibility of cells, tissues, organs or organisms to the harmful effect of ionizing radiation. Cells types affected Cells are least sensitive when in the S phase, then the G1 phase, then the G2 phase, and most sensitive in the M phase of the cell cycle. This is described by the 'law of Bergonié and Tribondeau', formulated in 1906: X-rays are more effective on cells which have a greater reproductive activity. From their observations, they concluded that quickly dividing tumor cells are generally more sensitive than the majority of body cells. This is not always true. Tumor cells can be hypoxic and therefore less sensitive to X-rays because most of their effects are mediated by the free radicals produced by ionizing oxygen. It has meanwhile been shown that the most sensitive cells are those that are undifferentiated, well nourished, dividing quickly and highly active metabolically. Amongst the body cells, the most sensitive are spermato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spindle Poison
A spindle poison, also known as a spindle toxin, is a poison that disrupts cell division by affecting the protein threads that connect the centromere regions of chromosomes, known as spindles. Spindle poisons effectively cease the production of new cells by interrupting the mitosis phase of cell division at the spindle assembly checkpoint (SAC). However, as numerous and varied as they are, spindle poisons are not yet 100% effective at ending the formation of tumors (neoplasms). Although not 100% effective, substantive therapeutic efficacy has been found in these types of chemotherapeutic treatments. The mitotic spindle is composed of microtubules (polymerized tubulin) that aid, along with regulatory proteins, each other in the activity of appropriately segregating replicated chromosomes. Certain compounds affecting the mitotic spindle have proven highly effective against solid tumors and hematological malignancies. Two specific families of antimitotic agents — vinca alkaloids and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitotic Spindle
In cell biology, the spindle apparatus refers to the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells. It is referred to as the mitotic spindle during mitosis, a process that produces genetically identical daughter cells, or the meiotic spindle during meiosis, a process that produces gametes with half the number of chromosomes of the parent cell. Besides chromosomes, the spindle apparatus is composed of hundreds of proteins. Microtubules comprise the most abundant components of the machinery. Spindle structure Attachment of microtubules to chromosomes is mediated by kinetochores, which actively monitor spindle formation and prevent premature anaphase onset. Microtubule polymerization and depolymerization dynamic drive chromosome congression. Depolymerization of microtubules generates tension at kinetochores; bipolar attachment of sister kinetochores to microtubules emanating from opposite cell pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinca Alkaloids
''Vinca'' alkaloids are a set of anti-mitotic and anti-microtubule alkaloid agents originally derived from the periwinkle plant ''Catharanthus roseus'' (basionym ''Vinca rosea'') and other ''vinca'' plants. They block beta-tubulin polymerization in a dividing cell. Sources The Madagascan periwinkle ''Catharanthus roseus'' L. is the source for a number of important natural products, including catharanthine and vindoline and the vinca alkaloids it produces from them: leurosine and the chemotherapy agents vinblastine and vincristine, all of which can be obtained from the plant. The newer semi-synthetic chemotherapeutic agent vinorelbine is used in the treatment of non-small-cell lung cancer and is not known to occur naturally. However, it can be prepared either from vindoline and catharanthine or from leurosine, in both cases by synthesis of anhydrovinblastine, which "can be considered as the key intermediate for the synthesis of vinorelbine." The leurosine pathway uses the Nug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitotic Inhibitor
A mitotic inhibitor is a drug that inhibits mitosis, or cell division. These drugs disrupt microtubules, which are structures that pull the chromosomes apart when a cell divides. Mitotic inhibitors are used in cancer treatment, because cancer cells are able to grow and eventually spread through the body (metastasize) through continuous mitotic division. Thus, cancer cells are more sensitive to inhibition of mitosis than normal cells. Mitotic inhibitors are also used in cytogenetics (the study of chromosomes), where they stop cell division at a stage where chromosomes can be easily examined. Mitotic inhibitors are derived from natural substances such as plant alkaloids, and prevent cells from undergoing mitosis by disrupting microtubule polymerization, thus preventing cancerous growth. Microtubules are long, ropelike proteins that extend through the cell and move cellular components around. Microtubules are long polymers made of smaller units (monomers) of the protein tubulin. Micro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
