Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experiments have confirmed that MTT-formazan colorimetry in its simplest form (incubation of intact worms with MTT and direct visualisation of any formazan formed) can be readily applied to several species of filariae including Onchocerca volvulus. Data is presented which will assist the development of quantitative MTT reduction viability tests for a selection of the smaller filarial species. Assays of pieces of Onchocerca gutturosa and O. volvulus females have led us to tentatively conclude that the tips of filariae, particularly the anterior ends, may well be metabolically the most active part of the worm. Selective sampling of these regions for Onchocerca might therefore be a useful indicator for the viability of the parasite. An example of how MTT-formazan colorimetry has been applied to yield additional data to support motility observations on the in vitro survival of male O. gutturosa is also given. The in vitro timecourse of worm death caused by 10 microM CGP 20376 on Acanthocheilonema viteae females has been examined by MTT reduction and compared with 6 other non-subjective parameters. The results suggests that the parameters examined could be divided into two groups according to the time taken for CGP 20376 to cause 50% inhibition (t50) of the parameter. Fast response parameters had t50's between 1 and 6 h (motility indices, 14CO2 evolution, adenine uptake and leucine uptake), they are more sensitive measures of viability and indicate possible worm damage which may or may not be reversible. Slow response parameters had t50's between 34 and 48.5 h (lactate output, MTT reduction and adenine leakage), and are probably linked with severe degenerative changes and are indicative of worm death.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The further application of MTT-formazan colorimetry to studies on filarial worm viability. 261 39

The nature of the lymphoid infiltrate in nodules of Onchocerca volvulus was assessed using monoclonal antibodies to lymphoid cell surface markers. Although B cells were generally absent, T cells were present, but in variable amounts. The ratio of T4+ (helper phenotype) to T8+ (suppressor-cytotoxic phenotype) was usually in the normal peripheral blood range of about 3, although ratios ranging from 1 to 10 were seen in selected areas of the onchocercoma. The possibility of immunosuppression through dominance of T4+, Leu-8+ cells (suppressor-inducer phenotype) within the T4+ population was also excluded. The T cells did not tend to concentrate in close proximity to the parasite, and there was no general bias in favour of the T suppressor cell phenotype (T8) within the infiltrate. Macrophages and dendritic cells were consistently observed and consisted of three defined cell types in approximately equal proportions: normal, unactivated macrophages (HLA-DR-, acid phosphatase positive), activated macrophages (HLA-DR+, acid phosphatase positive) and cells of dendritic morphology (HLA-DR+, acid phosphatase negative). These results are discussed in relation to immune suppression in filariasis.
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PMID:Human macrophages and T-lymphocyte subsets infiltrating nodules of Onchocerca volvulus. 390 94

Maintenance of adult male worms of the bovine filarial parasite Onchocerca gibsoni in vitro, in the presence of radioactive precursors, resulted in the time-dependent excretion-secretion of radiolabelled parasite macromolecules (ES). Molecules labelled with amino acids ([35S] methionine, [3H] leucine) covered a wide range of molecular weights, whereas labelling with [3H] glucosamine produced predominantly molecules of high molecular weight. Many of the products were recognized by antibodies in two serum pools from humans infected with Onchocerca volvulus. O. gibsoni ES may therefore provide a substitute source of material for studies on the ES of the less readily available human parasite.
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PMID:Biosynthetic radiolabelling of excretions-secretions of adult male Onchocerca gibsoni. 808 84

Nine monoclonal antibodies (mabs) have been produced against excretory-secretory products (ES) of adult male Onchocerca gibsoni. These mabs fail to interact with the highly cross-reactive phosphorylcholine (PC) group and with ES of the related rodent filarial parasites Acanthocheilonema viteae and Litomosoides carinii. Eight of the mabs are of the IgG isotype: 1 is an IgM. Three of the mabs, OGMES 4, 9, and 10, were each found by immunoprecipitation/SDS-PAGE analysis of [3H] leucine-labeled ES, to recognize a triplet of polypeptides of molecular weight 120, approximately 210, and approximately 260 kDa. No recognition was observed by any mab when [3H] glucosamine was employed as the radiolabel for ES. Western blotting employing [125I] as indicator system demonstrated that OGMES 7 recognized a molecule of 27 kDa, and OGMES 1, a molecule of approximately 210 kDa, albeit faintly. These mabs may be of value to researchers working on the isolation, characterization, and detection in the bloodstream of Onchocerca volvulus ES.
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PMID:Production of monoclonal antibodies against excretory-secretory products of adult male Onchocerca gibsoni. 910 19

The Ancylostoma secreted protein-2 of Necator americanus (Na-ASP-2) was one of the promising vaccine candidates against the most prevalent human hookworm species as adverse vaccine reaction has compromised further human vaccine trials. To elucidate the gene structure and the extent of sequence diversity, we determined the complete nucleotide sequence of the Na-asp-2 gene of individual larvae from 32 infected subjects living in 3 different endemic areas of Thailand. Sequence analysis revealed that the gene encoding Na-ASP-2 comprised 8 exons. Of 3 nucleotide substitutions in these exons, only one causes an amino acid change from leucine to methionine. A consensus conserved GT and AG at the 5' and the 3' boundaries of each intron was observed akin to those found in other eukaryotic genes. Introns of Na-asp-2 contained 23 nucleotide substitutions and 0-18 indels. The mean number of nucleotide substitutions per site (d) in introns was not significantly different from the mean number of synonymous substitutions per synonymous site (d(S)) in exons whereas d in introns was significantly exceeded d(N) (the mean number of nonsynonymous substitutions per nonsynonymous site) in exons (p<0.05), suggesting that introns and synonymous sites in exons may evolve at a similar rate whereas functional constraints at the amino acid could limit amino acid substitutions in Na-ASP-2. A recombination site was identified in an intron near the 3' portion of the gene. The positions of introns and the intron phases in the Na-asp-2 gene comparing with those in other pathogenesis-related-1 proteins of Loa loa, Onchocerca volvulus, Heterodera glycines, Caenorhabditis elegans and human were relatively conserved, suggesting evolutionary conservation of these genes. Sequence conservation in Na-ASP-2 may not compromise further vaccine design if adverse vaccine effects could be resolved whereas microheterogeneity in introns of this locus may be useful for population genetics analysis of N. americanus.
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PMID:Sequence conservation in the Ancylostoma secreted protein-2 of Necator americanus (Na-ASP-2) from hookworm infected individuals in Thailand. 2296 44