| third and fourth pharyngeal pouch syndrome | <syndrome> Also called the digeorge syndrome (dgs), this disorder is characterised by (1) low blood calcium levels (hypocalcaemia) due to underdevelopment (hypoplasia) of the parathyroid glands which control calcium; (2) underdevelopment (hypoplasia) of the thymus, an organ behind the breastbone in which lymphocytes mature and multiply; and (3) defects of the heart involving the outflow tracts more than from the heart. most cases of dgs are due to a microdeletion in chromosome band 22q11.2. A small number of cases have defects in other chromosomes, notably 10p13. Named after the american paediatric endocrinologist angelo digeorge. Another name for dgs is hypoplasia of the thymus and parathyroids. (12 Dec 1998) |
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| ultimobranchial pouch | A transient fifth pharyngeal pouch; it is now considered to be incorporated into the caudal pharyngeal complex, the cells of which become the parafollicular cells (C cells) of the thyroid. Uterovesical pouch, a pocket formed by the deflection of the peritoneum from the bladder to the uterus in the female. Synonym: excavatio vesicouterina, cavum vesicouterinum, vesicouterine pouch. (05 Mar 2000) |
| laryngeal pouch | A small diverticulum provided with mucous glands extending upward from the ventricle of the larynx between the vestibular fold and the lamina of the thyroid cartilage; it is a vestigial structure, being a much larger structure interdigitating with the neck musculature in some of the great apes where it serves as a resonating chamber. Synonym: sacculus laryngis, appendix ventriculi laryngis, Hilton's sac, laryngeal pouch. Origin: L. Sacculus (05 Mar 2000) |
| American Type Culture Collection | <cell culture> A key resource for cultured cells, located in Rockville, USA. (12 Dec 1998) |
| animal cell culture | <cell culture> Mammalian cells are fragile and harder to grow than other cell types, but their large-scale culturing is an economic boon because it allows for the production of proteins that are otherwise difficult or expensive or unethical to extract from living organisms. The cells are immobilised on a substrate and then perfused with culture medium, The cells are in a free suspension which is very gently mixed and aerated. (12 Nov 1997) |
| anoxic culture | A culture of anaerobicmicrobes which use inorganic substances other thanoxygen as their terminal electron acceptors. (09 Oct 1997) |
| anther culture | A plant culturing technique in which immature pollen is made to divide andgrow into tissue (either callus or embryonic tissue) in either aliquidmedium or on solid media. Pollen-containing anthers are removed from aflower and put in a culture medium, some microspheres survive and developinto tissue. If embryonic tissue develops, its put in a medium favorablefor shoot and root development, if its callus tissue, its put in asolution of hormones that will spur it to differentiate and develop shootand root tissue. (09 Oct 1997) |
| axenic culture | <cell culture, microbiology> A culture that contains only one microbial species. (02 Jan 1998) |
| batch culture | A closed system culture of microorganisms with specific nutrient types, temperature, pressure, aeration, and other environmental conditions, where only a few generations are allowed to grow before all nutrients are used up. Compare: continuous culture. (09 Oct 1997) |
| blood culture | <investigation, microbiology> A test which involves the incubation of a blood specimen overnight to determine if bacteria are present. (27 Sep 1997) |
| cell culture | General term referring to the maintenance of cell strains or lines in the laboratory. (18 Nov 1997) |
| roll-tube culture | A culture in a tube of medium which has been melted and allowed to solidify while the tube is being spun; the inside of the tube is thereby coated with a thin layer of solidified medium. (05 Mar 2000) |
| mixed lymphocyte culture | <investigation> Test to determine whether a patients and donor's white blood cells interact adversely. Often used to determine whether a person would be a suitable bone marrow donor for a particular patient. (16 Dec 1997) |
| mixed lymphocyte culture test | Measure of histocompatibility at the hl-a locus. Peripheral blood lymphocytes from two individuals are mixed together in tissue culture for several days. Lymphocytes from incompatible individuals will stimulate each other to proliferate significantly (measured by tritiated thymidine uptake) whereas those from compatible individuals will not. In the one-way mlc test, the lymphocytes from one of the individuals are inactivated (usually by treatment with mitomycin c or radiation) thereby allowing only the untreated remaining population of cells to proliferate in response to foreign histocompatibility antigens. (12 Dec 1998) |
| confluent culture | <cell biology> A cell culture in which all the cells are in contact and the entire surface of the culture vessel is covered. It is also often used with the implication that the cells have also reached their maximum density, though confluence does not necessarily mean that division will cease or that the population will not increase in size. (18 Nov 1997) |