| excitatory postsynaptic potential | The change in potential which is produced in the membrane of the next neuron when an impulse which has an excitatory influence arrives at the synapse; it is a local change in the direction of depolarisation; summation of these potential's can lead to discharge of an impulse by the neuron. (05 Mar 2000) |
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| junction potential | <physiology> Potential difference at the boundary between dissimilar solutions, arises from differences in diffusion constants between ions. (18 Nov 1997) |
| years of potential life lost | Measure of the relative impact of various diseases and lethal forces on society, computed by estimating the years that people would have lived if they had not died prematurely from injury, cancer, heart disease, etc. (05 Mar 2000) |
| zeta potential | <chemistry> The electrostatic potential of a molecule or particle, for example cell measured at the plane of hydrodynamic slippage outside the surface of the molecule or cell. Usually measured by electrophoretic mobility. Related to the surface potential and a measure of the electrostatic forces of repulsion the particle or molecule is likely to meet when encountering another of the same sign of charge. See: cell electrophoresis. (18 Nov 1997) |
| zoonotic potential | The potential for infections of subhuman animals to be transmissible to humans. (05 Mar 2000) |
| low malignant potential tumour | A neoplasm of the ovary, usually arising in young women, composed of complex epithelial hyperplasia without stromas invasion; may recur if incompletely removed surgically, but is clinically less aggressive than carcinoma. Synonym: low malignant potential tumour. (05 Mar 2000) |
| bilaterally small, smooth kidneys | <radiology> Generalised atherosclerosis, nephrosclerosis - benign and malignant, atheroembolic renal disease, chronic glomerulonephritis, papillary necrosis, hereditary diseases, hereditary chronic nephritis (Alport's syndrome), medullary cystic disease, amyloidosis (late), arterial hypotension Cf: other urographic patterns (12 Dec 1998) |
| carcinoma, non-small-cell lung | A heterogeneous aggregate of at least three distinct histological types of lung cancer, including squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. They are dealt with collectively because of the shared properties of poor response to conventional chemotherapy and the potential for cure with surgical resection in a fraction of patients. (12 Dec 1998) |
| carcinoma, small cell | An anaplastic, highly malignant, and usually bronchogenic carcinoma composed of small ovoid cells with scanty neoplasm. It is characterised by a dominant, deeply basophilic nucleus, and absent or indistinct nucleoli. There are admixtures of small cell lung carcinoma with other types of lung cancer. Small cell carcinomas are distinguished by their distinctive biological features, response to chemotherapy and radiotherapy, and by their nearly universal tendency to develop overt or subclinical metastases, which frequently eliminates surgery in most patients. (12 Dec 1998) |
| generalised small bowel disease | <radiology> Hypoproteinaemia, sprue, Whipple (12 Dec 1998) |
| mesenteric portion of small intestine | The freely movable portion of the small intestine supplied with a mesentery, comprising the jejunum and ileum. Synonym: mesenteric portion of small intestine. (05 Mar 2000) |
| ribonucleoproteins, small nuclear | Highly conserved nuclear RNA-protein complexes that function in RNA processing in the nucleus, including pre-mRNA splicing and pre-mRNA 3'-end processing in the nucleoplasm. The u3 snrnp is localised in the nucleolus, where it aligns into base pairs with the 28s rrna precursor in a still unidentified region and functions in pre-rrna processing. The u7 snrnp aligns into base pairs with a conserved sequence in the 3'-end of histone pre-mRNA and is an essential cofactor for the cleavage that creates the mature nonadenylated 3'-end. (12 Dec 1998) |
| ribonucleoproteins, small, u1 | A nuclear RNA-protein complex that plays a role in RNA processing. In the nucleoplasm, the u1 snrnp along with other small ribonucleoproteins (u2, u4-u6, and u5) assemble into spliceosomes that remove introns from pre-mRNA by splicing. The u1 snrnp base pairs with conserved sequence motifs at the 5'-splice site and recognises both the 5'- and 3'-splice sites and may have a fundamental role in aligning the two sites for the splicing reaction. (12 Dec 1998) |
| ribonucleoproteins, small, u2 | A nuclear RNA-protein complex that plays a role in RNA processing. In the nucleoplasm, the u2 snrnp along with other small ribonucleoproteins (u1, u4-u6, and u5) assemble into spliceosomes that remove introns from pre-mRNA by splicing. The u2 snrnp base pairs with conserved sequence motifs at the branch point, which associates with a heat- and rnaase-sensitive factor in an early step of splicing. (12 Dec 1998) |
| ribonucleoproteins, small, u4-u6 | A nuclear RNA-protein complex that plays a role in RNA processing. In the nucleoplasm, the u4-u6 snrnp along with the u5 snrnp preassemble into a single 25s particle that binds to the u1 and u2 snrnps and the substrate to form mature spliceosomes. There is also evidence for the existence of individual u4 or u6 snrnps in addition to their organization as a u4-u6 snrnp. (12 Dec 1998) |