| Schultze's mechanism | Expulsion of the placenta with the foetal surface foremost. (05 Mar 2000) |
|---|---|
| defense mechanism | A psychological means of coping with conflict or anxiety, e.g., conversion, denial, dissociation, rationalization, repression, sublimation, the psychic structure underlying a coping strategy, immunological mechanism vs. Non-specific defense mechanism. (05 Mar 2000) |
| double displacement mechanism | A special multisubstrate reaction in which, for a two-substrate, two-product (i.e., bi-bi) system, an enzyme reacts with one substrate to form a product and a modified enzyme, the latter then reacting with a second substrate to form a second, final product, and regenerating the original enzyme. An example of such a mechanism is found in the aminotransferases. More complex ping-pong mechanisms exist for enzymes having more than two substrates. Synonym: double displacement mechanism. (05 Mar 2000) |
| Douglas mechanism | Mechanism of spontaneous evolution in transverse lie; extreme lateral flexion of the vertebral column with birth of the lateral aspect of thorax before the buttocks. (05 Mar 2000) |
| Duncan's mechanism | Passage of the placenta from the uterus with the rough side foremost. (05 Mar 2000) |
| immunological mechanism | The groups of cells (chiefly lymphocytes and cells of the reticuloendothelial system) that function in establishing active acquired immunity (induced sensitivity, allergy). (05 Mar 2000) |
| ordered mechanism | A scheme for substrate binding and product release for multisubstrate enzymes; for a two-substrate two-product enzyme with an ordered mechanism, one particular substrate has to bind to the enzyme first followed by the other substrate; chemistry then occurs, products are formed and are released from the enzyme in a distinct order. More complex ordered schemes exist for enzymes having more than two substrates. Some of the dehydrogenases have such a mechanism. Synonym: ordered. (05 Mar 2000) |
| ordered on-random off mechanism | A scheme for substrate binding and product release for multisubstrate enzymes; for a two-substrate two-product enzyme with this mechanism, the individuals have to bind to the enzyme in a distinct order; however, once the products are formed they may dissociate from the enzyme in either order. It has been suggested that pyruvate kinase has such a mechanism. The random on-ordered off mechanism is simply the reverse of this mechanism. (05 Mar 2000) |
| adducted thumbs with mental reatardation | A syndrome with the following characteristic features: (1) neurologically:mental retardation and aphasia (lack of speech); (2) limbs: adducted (clasped) thumbs, absent extensor pollicis longus and/or brevis muscles to the thumb, shuffling gait, and leg spasticity; (3) growth: small body size; (4) skeleton: lumbar lordosis (sway back). The syndrome is inherited as an X-linked trait and so affects mainly boys. Alternative names include MASA syndrome ( MASA stands for mental retardation, aphasia, shuffling gait, and adducted thumbs), clasped thumb and mental retardation, congenital clasped thumb with mental retardation, and the Gareis-Mason syndrome. (12 Dec 1998) |
| mental | 1. <psychiatry> Pertaining to the mind, psychic. 2. <anatomy> Pertaining to the chin. Origin: L. Mens = mind, L. Mentum = chin (18 Nov 1997) |
| mental aberration | Disturbed thought or behaviour that connotes a psychological or psychiatric impairment. See: delusion. (05 Mar 2000) |
| mental age | A measure, expressed in years and months, of a child's measured intelligence relative to age norms as determined by testing with the Stanford-Binet intelligence scale. (05 Mar 2000) |
| mental agraphia | The inability to express ideas in writing. Synonym: mental agraphia. (05 Mar 2000) |
| mental apparatus | Mental structure consisting of thoughts, feelings, cognitions, and memories; in psychoanalysis, the topographic structure of the mind. (05 Mar 2000) |
| mental artery | <anatomy, artery> Distribution, chin; the terminal branch of the inferior alveolar; anastomoses, inferior labial artery. Synonym: arteria mentalis. (05 Mar 2000) |