| H-2 complex | <immunology> A term that denotes the genes of the mouse equivalent of the human major histocompatibility complex system. It is a set of genetic loci coding for Class I and Class II major histocompatibility complex antigens and for complement components. See: histocompatability antigen. (20 Jun 2000) |
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| primary complex | The typical lesions of primary pulmonary tuberculosis, consisting of a small peripheral focus of infection, with hilar or paratracheal lymph node involvement. (05 Mar 2000) |
| histocompatibility complex | A family of fifty or more genes on the sixth human chromosome that code for cell surface proteins and play a role in the immune response.Histocompatibility genes control the production of proteins on the outer membranes of tissue and blood cells, especially lymphocytes, and are vital elements in cell-cell recognition. The proteins also determine the level and type of immune response, and may serve other biochemical or immunologic functions. In the case of allografts, it is necessary to determine whether donor and recipient possess compatible sets of proteins (histocompatibility antigens), to minimise the likelihood of rejection. Histocompatibility testing (HLA tissue typing) provides this information. (05 Mar 2000) |
| HLA complex | <immunology> The major histocompatibility complex in humans. See: human lymphocyte antigens. (05 Mar 2000) |
| pyruvate dehydrogenase complex | <enzyme> A complex multienzyme system that catalyses the conversion of (pyruvate + CoA + NAD) to (acetyl CoA + CO2 + NAD). (18 Nov 1997) |
| pyruvate dehydrogenase complex deficiency | An autosomal recessive pyruvate metabolism disorder resulting from deficient enzyme activity in one of several proteins of pyruvate dehydrogenase complex, resulting in deficiency of acetyl CoA. Deficiency in acetyl CoA product reduces the synthesis of acetylcholine, thereby causing neurological abnormalities. Clinical presentations include lactic acidosis, mental retardation, and ataxia. (12 Dec 1998) |
| pyruvate dehydrogenase complex inactivase | <enzyme> Pharmacological action: enzyme inhibitor Registry number: EC 3.4.- (26 Jun 1999) |
| S gene complex | <molecular biology> Genes coding for molecular components of the pollen stigma recognition system in the cabbage genus Brassica). The gene products govern the self incompatibility response and include a glycoprotein found on the stigma surface and a lectin on the pollen grain surface that binds to the stigma glycoprotein. (18 Nov 1997) |
| Shone's complex | An obstructive lesion of the mitral valve complex with left ventricular outflow obstruction and coarctation of the aorta. (05 Mar 2000) |
| sicca complex | Dryness of the mucous membranes, as of the eyes and mouth, in the absence of a connective tissue disease such as rheumatoid arthritis. (05 Mar 2000) |
| signal peptidase complex | A peptide present on proteins that are destined either to be secreted or to be membrane components. It is usually at the N terminus and normally absent from the mature protein. Normally refers to the sequence (ca 20 amino acids) that interacts with signal recognition particle and directs the ribosome to the endoplasmic reticulum where co translational insertion takes place. Could also refer to sequences that direct post translational uptake by organelles. Signal peptides are highly hydrophobic but with some positively charged residues. The signal sequence is normally removed from the growing peptide chain by signal peptidase, a specific protease located on the cisternal face of the endoplasmic reticulum. See: signal recognition particle. (18 Nov 1997) |
| spike and wave complex | A generalised, synchronous pattern seen on the electroencephalogram, consisting of a sharply contoured fast wave followed by a slow wave; particularly found in patients with generalised epilepsies. Spike and wave complexes are often characterised by their frequency, e.g., s low spike and wave, fast spike and wave. (05 Mar 2000) |
| neoplasms, complex and mixed | Neoplasms composed of more than one type of neoplastic tissue. (12 Dec 1998) |
| nitrogenase complex | <biochemistry> A system of enzymes used by nitrogen-fixing ATP is present. (09 Oct 1997) |
| sucrase-isomaltase complex | <enzyme> An enzyme complex found in the brush border membranes of the small intestine. It is believed to be an enzyme complex with different catalytic sites. Its absence is manifested by an inherited disease called sucrase-isomaltase deficiency. Registry number: EC 3.2.1.- (12 Dec 1998) |