| h substance | <haematology> A polysaccharide precursor molecule which is used to make the antigens on the surface of human blood cells that are classified in the ABO blood group system. (09 Oct 1997) |
|---|---|
| H(2) fumarate reductase | <enzyme> Contains hydrogenase coupled with fumarate reductase by one or more unknown intermediary electron carriers; fumarate yields acetate + succinate Registry number: EC 1.- (26 Jun 1999) |
| H(2)-proteinase | <enzyme> From habu snake, trimeresurus flavoviridis; non-haemorrhagic, non-glycosylated protein consisting of 201 amino acids; mw 23 kD; has typical zn-chelating sequence Registry number: EC 3.4.24.- Synonym: h2-proteinase h2-proteinase, trimeresurus (26 Jun 1999) |
| H-2 antigen | <immunology> Antigen coded in the major group of transplantation antigens in the mouse. See: H-2 complex, histocompatability antigen. (20 Jun 2000) |
| 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) |
| H-protein lipoyltransferase | <enzyme> Requires lipoyl-AMP and apo-h-protein to generate the active h-protein of the glycine cleavage system Registry number: EC 2.3.1.- Synonym: lipoyl-AMP-n(epsilon)-lysine lipoyltransferase (26 Jun 1999) |
| H-R conduction time | Conduction of the cardiac impulse through the ventricular myocardium, represented by the QRS complex in the electrocardiogram. H-R conduction time is from the onset of the first high frequency component of the His bundle electrogram to the onset of the QRS complex of the surface electrocardiogram (normally 43 ± 12 msec); H-V conduction time is from the onset of the first high frequency component of the His bundle electrogram to the onset of the ventricular electrogram (normally approximates the H-R interval but may be a little shorter). Synonym: ventricular conduction. (05 Mar 2000) |
| h-ras | <oncogene> A point-mutated proto-oncogene that is found in melanoma and in carcinoma of colon, lung and pancreatic tissue. (10 Oct 1997) |
| H-shape vertebrae | <radiology> Sharply delimited depression of the central portion of the endplates of the vertebrae, producing a stocky H shape on radiographs, as in sickle cell anaemia. (05 Mar 2000) |
| H-tetanase | <microbiology> Behring's term for the haemolytic constituent of tetanus toxin. (05 Mar 2000) |
| H-type fistula | <gastroenterology, surgery> A rare form of congenital tracheoesophageal fistula in which there is no oesophageal atresia, manifest as aspiration pneumonias. Synonym: H-type tracheoesophageal fistula. (05 Mar 2000) |
| H-type tracheoesophageal fistula | <gastroenterology, surgery> A rare form of congenital tracheoesophageal fistula in which there is no oesophageal atresia, manifest as aspiration pneumonias. Synonym: H-type tracheoesophageal fistula. (05 Mar 2000) |
| H-V conduction time | Conduction of the cardiac impulse through the ventricular myocardium, represented by the QRS complex in the electrocardiogram. H-R conduction time is from the onset of the first high frequency component of the His bundle electrogram to the onset of the QRS complex of the surface electrocardiogram (normally 43 ± 12 msec); H-V conduction time is from the onset of the first high frequency component of the His bundle electrogram to the onset of the ventricular electrogram (normally approximates the H-R interval but may be a little shorter). Synonym: ventricular conduction. (05 Mar 2000) |
| H-V interval | The time from the initial deflection of the His bundle (H) potential and the onset of ventricular activity (normally 35-45 msec). (05 Mar 2000) |
| h-y antigen | A sex-specific cell surface antigen produced by the sex-determining gene of the y chromosome in mammals. It causes syngeneic grafts from males to females to be rejected and interacts with somatic elements of the embryologic undifferentiated gonad to produce testicular organogenesis. (12 Dec 1998) |