| 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) |
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| 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) |
| ribonucleoproteins, small, u5 | A nuclear RNA-protein complex that plays a role in RNA processing. In the nucleoplasm, the u5 snrnp along with u4-u6 snrnp preassemble into a single 25s particle that binds to the u1 and u2 snrnps and the substrate to form mature spliceosomes. (12 Dec 1998) |
| RNA, small nuclear | Short chains of RNA found in the nucleus. Their function is to remove the introns (nontranslated intervening sequences) from mRNA precursors, thereby bringing the two exons (coding segments) together into correct juxtaposition for enzymatic splicing at the correct point. The resulting mRNA is now ready to leave the nucleus. (12 Dec 1998) |
| mucosa of small intestine | The mucous coat of the small intestine. Synonym: tunica mucosa intestini tenuis. (05 Mar 2000) |
| muscular coat of small intestine | Muscular layer of the wall of the small intestine. Synonym: tunica muscularis intestini tenuis. (05 Mar 2000) |
| sarcoma, small cell | A sarcoma characterised by the presence of small cells, cells measuring 9-14 micrometers with a faint or indistinct rim of cytoplasm and an oval-to-elongated nucleus with relatively dense chromatin. (12 Dec 1998) |
| proximal small bowel disease | <radiology> Giardia, eosinophilic gastroenteritis, Zollinger-Ellison (12 Dec 1998) |
| serosa of small intestine | Serous coat of the small intestine; the peritoneal covering of the external surface of the small intestine. Synonym: tunica serosa intestini tenuis. (05 Mar 2000) |