pressure necrosis
| tonic contraction | Sustained contraction of a muscle, as employed in the maintenance of posture. (05 Mar 2000) |
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| escape contraction | Escaped beat, an automatic beat, usually arising from the A-V junction or ventricle, occurring after the next expected normal beat has defaulted; it is therefore always a late beat, terminating a longer cycle than the normal. Synonym: escape contraction. (05 Mar 2000) |
| escape ventricular contraction | An escape beat arising in the ventricle. (05 Mar 2000) |
| excitation contraction coupling | <physiology> Name given to the chain of processes coupling excitation of a muscle by the arrival of a nervous impulse at the motor end plate to the contraction of the filaments of the sarcomere. The crucial link is the release of calcium from the sarcoplasmic reticulum and the analogy is often drawn between this and stimulus secretion coupling, that also involves calcium release into the cytoplasm. (18 Nov 1997) |
| uterine contraction | Contraction of the uterine muscle. (12 Dec 1998) |
| frontal zone contraction theory | Model proposed to account for the movement of giant amoebae in which cytoplasmic contraction at the front of the leading pseudopod (fountain zone) pulls viscoelastic cytoplasm forward in the centre of the cell and forms a tube of more rigid cytoplasm immediately below the plasma membrane behind the active region. The peripheral contracted cytoplasm relaxes into a weaker gel at the rear and is pulled forward in its turn. Contrasts with the ectoplasmic tube contraction model. (18 Nov 1997) |
| front-tap contraction | Contraction of the calf muscles when the anterior surface of the leg is struck. Synonym: Gowers' contraction. (05 Mar 2000) |
| acute tubular necrosis | <nephrology> A kidney disorder that results in damage to the renal tubule cells leading to acute renal failure. Acute tubular necrosis can result from any condition which deprives the kidney of oxygen (ischaemia). Acute tubular necrosis may occur as a complication of shock, trauma or sepsis. Conditions such as diabetes or liver disease can predispose people to the development of acute tubular necrosis. Certain medications (for example aminoglycosides, amphotericin B, cyclosporine) are known to cause acute tubular necrosis as a toxic side effect. Radiopaque contrast dyes, used in some radiologic procedures, may also result in acute tubular necrosis as a rare complication from contrast dye use. Acronym: ATN (13 Nov 1997) |
| aseptic necrosis | <orthopaedics, pathology> Condition in which poor blood supply to an area of bone leads to bone death. Also called avascular necrosis and osteonecrosis. (12 Dec 1998) |
| avascular necrosis | <radiology> Aetiology (PLASTIC RAGS): P pancreatitis, L lupus, A alcohol, S steroids, T trauma, I idiopathic, infection, C caisson disease, collagen vascular disease, R radiation, rheumatoid arthritis, A amyloid, G Gaucher disease, S sickle cell disease findings: sclerosis, crescent sign, collapse (e.g., of femoral head) see also: staging (12 Dec 1998) |
| avascular necrosis staging | <radiology> Stage CT/X-ray bone scan I - cold/hot spot II sclerotic focus with osteopenic ring III crescent sign (subchondral lucency) IV articular collapse flattening of femoral head sensitivity 86% 78% specificity 79% 75% see also: avascular necrosis (AVN) (12 Dec 1998) |
| bridging hepatic necrosis | Area of liver necrosis which bridges adjacent portal areas and central veins; subsequent post-necrotic collapse and fibrosis is likely to result in cirrhosis. (05 Mar 2000) |
| p60 tumour necrosis factor receptor-associated kinase | <enzyme> Interacts with and causes phosphorylation of the cytoplasmic domain of the tnf receptor Registry number: EC 2.7.10.- Synonym: p60 tnf receptor-associated kinase, p60-trak (26 Jun 1999) |
| papillary necrosis | <radiology> Mnemonic: POST CARD, P pyelonephritis, O obstruction, S sickle cell disease, T TB, C cirrhosis (EtOH), A analgesics (phenacetin and aspirin), R renal vein thrombosis, D diabetes (12 Dec 1998) |
| receptors, tumour necrosis factor | Cell surface receptors that bind tumour necrosis factor and trigger changes which influence the behaviour of cells. The two recognised tumour necrosis factor receptors are designated alpha and beta receptors. Both receptors bind both alpha and beta tumour necrosis factors with high affinity, and both are members of the nerve growth factor receptor family. (12 Dec 1998) |