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)

Adult Onchocerca volvulus were enzymatically isolated with collagenase from excised nodules and kept in TC medium 199 with Hank's salts supplemented with various sera. Male and female worms survived in the culture medium and 10% human serum on average for about 11 days (maximum 28 days) and 14.5 days (maximum 42 days). Up to 4,000 microfilariae were expelled by each female per day, but the production of new oocytes or development of embryos could not be observed in vitro.
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PMID:Observations on adult Onchocerca volvulus maintained in vitro. 608 8

The surface ultrastructure of male and female adult worms of Onchocerca volvulus obtained from human nodules by the technique of collagenase digestion has been compared with that of worms excised manually without the aid of enzyme treatment. No topographical differences have been identified.
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PMID:Comparative surface ultrastructure of adult Onchocerca volvulus recovered from human nodules by dissection or collagenase digestion. 633 Oct 18

The macrofilaria population was analysed in a hyperendemic focus in western Upper Volta to determine the effect of eight years of Simulium control on the adult Onchocerca volvulus. During the first months of 1983 in three neighbouring villages 629 out of 786 inhabitants were examined for onchocerciasis and from 76 patients as far as possible all onchocercomata were extirpated. The macrofilariae were isolated from the nodules after collagenase digestion and examined microscopically. There were no major differences between men and women or different age groups. The average worm burden was 9.8 live macrofilariae per patient. All worms were several years old but developing sperms were found in 94% of the male and embryos in 55% of the female filariae. 36% of all worms were dead and 23% were calcified. Compared with the findings in a Liberian focus with continuous transmission it is concluded that the interruption of the transmission has lead to a reduced worm burden of entirely old worms but that a few more years of control will be needed until the production of microfitariae will end.
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PMID:Parasitological studies on "Onchocerca volvulus" eight years after interruption of the transmission in Upper Volta. 668 50

Using ELISA, we studied excreted-secreted (ES) antigens of adults O. volvulus obtained from nodules digested by collagenase and kept alive in vitro. It seems that only the female worms produce these antigens. They probably have a much higher specificity than somatic antigens (male or female worms extracts): a comparison was made in a study of 163 heterologous sera by ELISA. With this new sort of antigen the onchocerciasis serology seems to have a specificity not achieved until now. Its diagnosis value was studied with 61 proved onchocerciasis sera and 177 sera from people living in endemic areas. The percentages of positivity are 79 and 52 p. 100 respectively; the micro-ELISA is particularly advantageous for studying large numbers of sera and for seroepidemiology. We also compared the results obtained by the immunofluorescent antibody test using male and female O. volvulus and female D. viteae frozen sections. No significant differences were found in the study of these 3 antigens that have many non-specific fractions as all somatic antigens do.
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PMID:[Serodiagnosis of onchocerciasis by micro-ELISA using homologous somatic and metabolic antigens (excreted-secreted). Comparison with indirect immunofluorescence]. 675 43

Thirty-eight nodules containing adults of Onchocerca volvulus were removed from 36 patients who had no detectable microfilariae in skin snips. Worms were digested from nodules in collagenase solution, maintained alive in vitro, and the number, sex, and state of fecundity were recorded. A total of 48 female and 8 male worms were recovered; 39 females were in the nodules without the presence of a male. Eleven females (22.9%) had microfilariae in utero or produced microfilariae in vitro; seven of these were found together with males in the nodules while four were not. No nodules were found around male worms unless a female was also present. These observations indicate that the nodule forms only around female worms and that mating probably occurs before or early during nodule formation. Furthermore, the production of microfilariae by the the female is not essential for nodule formation since many nodules contained non-fecund, living females.
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PMID:Early formation of the nodule in Guatemalan onchocerciasis. 707 89

Tissue culture fluid NCTC 135 (Hank's base) was compared to water and to saline as incubation media for the detection of microfilariae of Onchocerca volvulus in skin snips. NCTC 135 allowed detection of significantly more positive persons than did water (P less than 0.001) or saline (P less than 0.05) when two snips per person were incubated for periods of 0.5 or 24 hours. In addition, snips containing microfilariae were incubated in NCTC 135 or in saline and the number of emerged microfilariae was determined at various intervals of time up to 24 hours. After incubation, snips were either fixed in 10% formalin, serially sectioned, and the microfilariae counted, or they were digested in collagenase solution to free unemerged microfilaire. Of the total number of microfilariae present in the snips, 43.9% +/- 18.5, 80.2% +/- 22.2, 83.0% +/- 19.5, and 85.3% +/- 18.0 had emerged by 0.5, 4, 8, and 24 hours of incubation, respectively. Of the microfilariae that remained in the skin after incubation, most were located deep in the dermis.
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PMID:Parasitological diagnosis of onchocerciasis: comparisons of incubation media and incubation times for skin snips. 735 25

The application of a new technique is described permitting a better recognition of activities of drugs on macrofilariae of Onchocerca volvulus. In two villages of a hyperendemic focus in Liberia onchocercomata were excised from untreated persons and from patients treated with conventional doses of suramin or metrifonate. The adult worms were enzymatically isolated with collagenase and microscopically examined for degenerative alterations including calcifications and for the presence of eggs and embryos in the female parasites. Six weeks after the last dose of suramin the degenerative alterations could not be distinguished qualitatively from those in untreated worms, but a statistically significant macrofilaricidal efficacy could be shown by quantitative analyses, although more than half of the parasites were still alive at this early date. Metrifonate did not show any macrofilaricidal effect.
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PMID:Analysis of enzymatically isolated adults of Onchocerca volvulus after treatment of patients with suramin or metrifonate. 741 75

The persistence of the effects of ivermectin on the viability, morphology and reproductivity of adult Onchocerca volvulus was examined eighteen months after treatment with a single or five six-monthly doses of ivermectin and compared with untreated controls. Treated nodules were removed from patients participating in a randomised controlled trial of ivermectin in Sierra Leone. Adult filariae, 545 females and 348 males, were isolated by collagenase digestion. The nodules were significantly smaller, contained fewer young worms and supported lower microfilarial production in those treated with five doses of ivermectin. The productivity index, a measure of the reproductive potential of a worm population, was still reduced by 83% eighteen months after five doses and by 63% after a single dose compared to controls. These results show that worms recover their fertility even after multiple doses of ivermectin, but do so slowly compared to standard dosage intervals. In addition ivermectin may have a partial chemoprophylactic effect which contributes to the maintenance of low microfilarial production in conditions of on-going transmission.
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PMID:How long do the effects of ivermectin on adult Onchocerca volvulus persist? 813 72

An Onchocerca volvulus expression library was differentially screened to identify a molecular marker distinguishing sowda (lichenified onchodermatitis) from other onchocerciasis forms. One clone, PG3, was recognized by pooled sera from patients with sowda, but not by pooled sera from patients with generalized onchocerciasis; it was not recognized by sera from patients with lymphatic filariasis or other helminth infections. The DNA of PG3 hybridized strongly with O. volvulus Eco RI-digested DNA, but not with DNA from Brugia spp., Trichinella spp., and humans. A weak reaction was observed with DNA from O. gibsoni and Acanthocheilonema viteae. The PG3 DNA sequence showed a high homology with both human and nematode collagens. Confirmation of the collagen-like nature of the sowda-specific PG3 product was obtained by amino terminal sequencing of the PG3 expression product, as well as by demonstrating its susceptibility to collagenase digestion. The characteristic recognition of the O. volvulus collagen specified by clone PG3 was confirmed by measuring antibody levels to the expressed product in individual sowda and generalized onchocerciasis sera, respectively. Identification of a nematode collagen antigen mainly recognized in sowda patients raises the possibility that this extreme form of dermatitis might arise through cross-reactivity between anti-O. volvulus collagen antibodies and human collagen. However, a relationship between the PG3 recognition by antibodies and the sowda pathogenesis could not be demonstrated.
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PMID:Identification of Onchocerca volvulus collagen as an antigen mainly recognized by antibodies in chronic hyper-reactive onchodermatitis (sowda). 864 4

A polymerase chain reaction (PCR) of a 150-bp tandem repeat of Onchocerca volvulus (O-150) combined with Southern-blot hybridization to species-specific DNA probes was employed for DNA detection. O-150 was amplified from parasites originating from Uganda, Benin, Cameroon, Liberia, Ghana, Burkina Faso, Mali, and Zaire and was successfully hybridized to digoxigenin-labeled oligonucleotides. To investigate the sensitivity of the PCR, 2 skin biopsies were taken from each of 227 persons from Uganda with proven O. volvulus infections but with low microfilaria (mf) densities due to ivermectin treatment. One biopsy was tested by PCR and the other was digested using collagenase to assess the total number of mf. The PCR revealed 76.2% of the samples to be positive, and the collagenase method showed that 78.9% were positive, indicating similar sensitivity for the two methods. It is probable that for both techniques the biopsy must contain at least one live mf or fragments of a dead mf. In this study, no free or circulating O. volvulus DNA could be detected in skin biopsies by PCR.
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PMID:Sensitivity of a polymerase chain reaction-based assay to detect Onchocerca volvulus DNA in skin biopsies. 873 77


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