Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A technique for the assessment of the total number of microfilariae in skin snips from onchocerciasis patients is described. For the digestion of the skin tissue the biopsies are incubated at room temperature for 24 hours in medium 199, containing 3 mg/ml collagenase and antibiotics. This process leaves the microfilariae unharmed. A comparative study of the emergence of the microfilariae in different media showed that only 20% of the total number were released after 30 minutes in distilled water. After 24 hours incubation in isotonic saline 80% were found.
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PMID:A simple technique to assess the total number of Onchocerca volvulus microfilariae in skin snips. 20 77

The different methods used for the parasitological diagnosis of onchocerciasis are compared to test their reliability, sensitivity and practicability under field conditions in the Sudan-Savanna area. Two skin snips taken from both iliac crests with a sclerocorneal punch give the best results during large scale field surveys. The incubation of biopsies in normal saline solution is the most sensitive technique and the results may be further improved by filtration on millipore filter-paper and collagenase digestion. However, counting microfilariae emerged after 30 minutes in distilled water is the easiest method and gives a reasonably good reliability for comparison of the results in space and time. The lack of sensitivity can be compensated for by incubation of the negative specimen during 24 hours in saline solution.
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PMID:[Parasitological diagnosis of onchocerciasis. A critical review of present methods (author's transl)]. 74 26

The effects of single and multiple doses of ivermectin on mortality and morphology were assessed in over 700 female Onchocerca volvulus worms and the effects on embryogenesis were assessed in 490. Nodules were surgically removed from Sierra Leoneans recruited from a double-blind placebo controlled study of ivermectin given at six-monthly intervals. Nodules were digested in collagenase to isolate whole adult worms. After four or five doses of ivermectin there were significant increases in the numbers of discoloured and calcified worms and possibly a trend towards increased mortality, but this was not seen consistently. There was no evidence of a prophylactic effect of the drug. Worms were then homogenised and embryograms constructed. A single dose of ivermectin produced large numbers of degenerating intrauterine microfilariae, but embryonic development occurred normally. After multiple doses we observed almost complete cessation of embryogenesis, with a highly significant decrease in the numbers of viable multicellular embryonic stages, while oocytes appeared to be produced normally. Development is probably impeded at the single cell stage, possibly because of reduced fertilization. In planning the future role of ivermectin as a control measure for onchocerciasis it is crucial to determine if these effects on embryogenesis are reversible.
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PMID:The effect of repeated doses of ivermectin on adult female Onchocerca volvulus in Sierra Leone. 129 32

Ivermectin is a safe, effective microfilaricide and microfilarial suppressant for Onchocerca volvulus; but in single doses of 100-200 micrograms/kg body weight it has no macrofilaricidal action. The present trial aimed to determine whether 6 doses of 100 micrograms/kg ivermectin, given at 2-week intervals, would kill the adult worms. Eighty-two nodules from 28 otherwise healthy adult male Liberian patients treated with this ivermectin schedule, and 102 nodules from a similar group of 25 control patients, were removed four months after the last dose of ivermectin. They were coded and assessed in a masked fashion either by routine histology or by examination of whole worms extracted from the nodules after collagenase digestion. The drug had no visible effect on adult male worms. More adult female worms were assessed as moribund or dead in the ivermectin-treated group than in the control group (for the collagenase digests P = 0.09; for the histological assessment P = 0.47). The data suggest that repeated dosage with ivermectin may lead to a slow attrition of some female worms and this possibility should be investigated in patients receiving regular doses every 3, 6 or 12 months as part of onchocerciasis control programmes.
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PMID:Viability of adult Onchocerca volvulus after six 2-weekly doses of ivermectin. 186 Jan 46

A new technique for assessing vital and degenerative microfilariae (mf) in different skin layers of onchocerciasis patients is described. Vertical sections at least 5 mm deep were collected from the surgical nodulectomy wounds before and 2, 4 and 28 days after treatment with ivermectin and fixed in ethanol. Skin biopsies were punched horizontally with trephines and digested enzymatically with collagenase. In untreated biopsies 80% of the mf were located in the uppermost layer of 1 mm and only 1.2% were degenerated. After treatment with ivermectin the total number of mf was significantly reduced, and the distribution of living and remnant mf in the different skin layers had changed. The proportion of degenerated mf had increased markedly, but did not exceed 6% of the total pre-treatment mf level, i.e., the vast majority of the mf had actually disappeared from the skin. It is suggested that ivermectin reduces microfilarial motility slightly, and that mf are then attacked by adhering immunocompetent cells of the host and cleared by the lymphatic drainage.
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PMID:Effect of ivermectin on the vertical distribution of Onchocerca volvulus microfilariae in the skin. 238 96

We examined the ability of two filarial species, Onchocerca volvulus and Brugia malayi, to solubilize collagen molecules from native collagen fibrils. Collagenolytic activity was detected in extracts of adult worms, in living microfilariae of O. volvulus and in live infective larvae and adult female worms of B. malayi. Excretion-secretion factors produced in vitro by infective larvae of B. malayi also contained large amounts of collagenase. Studies with enzyme inhibitors suggest that the latter may be a metallo-protease. Antibodies to filarial collagenase were present in sera from patients with onchocerciasis and brugian filariasis and from mice immunized with B. malayi. These antibodies and a monoclonal antibody raised against O. volvulus antigens immunoprecipitate filarial collagenase but appear not to be directed against the active site of the enzyme.
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PMID:Studies on a filarial antigen with collagenase activity. 242 72

Thirty adult male nodule carriers from a hyperendemic onchocerciasis area in the Liberian rain forest were treated with high doses of diethylcarbamazine (30 mg/kg/d) over one week. Another ten patients received placebo tablets and served as a control. All detectable nodules were removed from half of the patients at two months and from the remaining patients at ten months after chemotherapy. The adult worms in the nodules were examined for pathological alterations by the collagenase technique including embryogram, and by histology. No macrofilaricidal effect was observed at either time, and no significant reduction of microfilariae in the uteri of the female worms or in the tissue of the nodules was seen. Two months after the therapy there was a significant increase of degenerated stretched intrauterine microfilariae but this effect was no longer observed after ten months. No pathological effect was seen on the intrauterine coiled microfilariae. On the contrary, their number had significantly increased after ten months which could mean a stimulation of the embryogenesis. No effect on spermatogenesis was observed. Both techniques, the collagenase digestion and the histological examination of the nodules, provided similar results to demonstrate that there was no marked long lasting effect on O. volvulus after a treatment with high doses of diethylcarbamazine.
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PMID:Effects of high doses of diethylcarbamazine on adult Onchocerca volvulus examined by the collagenase technique and by histology. 284 64

In a village hyperendemic for onchocerciasis in Burkina Faso, where the vector had been controlled by the Onchocerciasis Control Programme since 1976, 65 patients were treated with doses of 37 to 71 mg/kg suramin in 1979. The viability and fertility of the adult parasites were studied in 217 nodules excised from 42 patients one month to four years after treatment using the collagenase technique. Most of the worms had survived the treatment. Male worms were more susceptible to suramin than female worms. The development of intrauterine stages initially continued, but was completely suppressed after several months. The female worms remained sterile in those patients who had received more than 60 mg/kg suramin. In other ones 11 and 13% of the female worms showed new embryonic stages in the uteri during two follow-up examinations in the second year. In a final examination in 1983 the reproduction had declined again. However, the reproductivity of the superannuated worms had considerably decreased in the untreated patients as well. All patients had shown a very high microfilardermia in 1979. After treatment the microfilarial densities dropped to levels near zero depending on the dose of suramin administered, but in none of the patients was the reduction complete during the first year of the treatment. Microfilariae gradually reappeared in the second year in several patients who had received less than 60 mg/kg suramin. In the final follow-up in 1983 most of the treated patients had become negative in skin counts, although they still harboured viable worms.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Suramin in the treatment of onchocerciasis: the efficacy of low doses on the parasite in an area with vector control. 408 76

The microfilarial density in 400 skin snips from 100 patients was determined using the standard technique of the Onchocerciasis Chemotherapeutic Research Centre (OCRC method), the method used by the Onchocerciasis Control Programme (OCP method), and also after collagenase digestion. The OCRC method was fairly consistent and detected 84% of the total microfilariae. The OCP method gave a density which was consistently 20% less than the OCRC method, indicating that the increase in weight in skin snips following incubation in saline was fairly predictable. It is concluded that collagenase digestion is not worthwhile as a routine technique in chemotherapeutic trials, for which the OCRC method is recommended.
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PMID:The chemotherapy of onchocerciasis V. A standard method for the determination of microfilarial density in skin snips. 624 26

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


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