Search PubMed⌕ Search

Biomedical subjects

J I Bruce

Publications and source records attributed to J I Bruce.

At least 37 records · Page 2Linked to original sources
PubMed1987

Tolerance of Kenyan Schistosoma mansoni to oxamniquine.

Although 30 mg/kg oxamniquine produced high levels (85.5 to 99.5%) of egg reduction in Kenyan children infected with Schistosoma mansoni after a single oral treatment, cure rates from children at Mwea in Kirinyaga district were lower than those from Machakos (58% v. 74%). Redosing uncured children confirmed this lower cure rate (36% v. 83%). Isolates from infected children were passaged into mice and dosed with oxamniquine. Lower than expected reductions in worm numbers were obtained, suggesting that oxaminiquine tolerant S. mansoni are present in the normal worm population in Kenya. It is concluded that mass use of oxamniquine at 30 mg/kg may produce problems of drug resistance.

Administration, Oral↗
PubMed1987

Enzymatic differences between hycanthone-resistant and sensitive strains of Schistosoma mansoni.

1. Hycanthone-sensitive and resistant adult worms of Schistosoma mansoni were found to have generally similar specific activities in ten enzymes of carbohydrate metabolism. 2. Kinetic analyses revealed that pyruvate kinase, glucose-6-phosphate (G6P) dehydrogenase and malate dehydrogenase from both strains possessed similar Michaelis-Menten constants and were not inhibited by hycanthone. 3. Hexokinase and lactate dehydrogenase from the drug-resistant strain were not inhibited by hycanthone and showed three to five times greater Km values than those from the drug-sensitive worms which were also inhibitable by hycanthone. 4. Hycanthone more drastically affected the Vmax of phosphofructokinase from the hycanthone-sensitive parasite. 5. These data showed that the hycanthone inhibitable enzymes were generally from the drug-sensitive strain whereas the enzymes from drug-resistant worms are mostly hycanthone insensitive.

Animals↗
PubMed1987

Drug resistance in schistosomiasis: a review.

Drug resistance associated with the treatment of human schistosomiasis appears to be an emerging problem requiring more attention from the scientific community than the subject currently receives. Drug-resistant strains of Schistosoma mansoni have been isolated by various investigators as a result of laboratory experimentation or from a combination of field and laboratory studies. Review of this data appears to indicate that the lack of susceptibility observed for some of the isolated strains cannot be ascribed solely to previous administration of antischistosome drugs and thus further studies are required to elucidate this phenomena. Strains of S. mansoni have now been identified from Brazil which are resistant to oxamniquine, hycanthone and niridazole; from Puerto Rico which are resistant to hycanthone and oxamniquine; and from Kenya which are resistant to niridazole and probably oxamniquine. Strains derived by in vitro selection and resistant to oxamniquine and possibly to oltipraz are also available. All of these strains are currently maintained in the laboratory in snails and mice, thus providing for the first time an opportunity for indepth comparative studies. Preliminary data indicates that S. haematobium strains resistant to metrifonate may be occurring in Kenya. This problem could poise great difficulty in the eventual development of antischistosomal agents. Biomphalaria glabrata from Puerto Rico and Brazil were found to be susceptible to drug-resistant S. mansoni from each country.

Animals↗
PubMed1985

Transplantation of Schistosoma japonicum daughter sporocysts in Oncomelania hupensis.

Schistosoma japonicum daughter sporocysts obtained from infected Oncomelania hupensis hupensis were successfully transplanted to parasite-free O. hupensis hupensis. Survival and infection rates of recipient snails were 80% and 75% respectively. Intramolluscan development of transplanted daughter sporocysts in recipient snails appears to proceed in a similar manner as those reported for transplanted S. mansoni and S. haematobium in their respective snail intermediate hosts. Complete colonization of the digestive gland of recipient snails by sporocysts was observed 80 days after transplantation. Cercarial production during a 10-day observation from recipient snails was characterized by periods of high and low and irregular daily emissions. The average daily cercarial production was 150 per snail. Cercariae produced by recipient snails were infective to mice. Of those cercariae exposed to mice, approximately 30% developed to adult schistosomes. These results have definitive utility in the maintenance of S. japonicum in the laboratory.

Animals↗
PubMed1983

Efficacy of amoscanate against experimental schistosomal infections in monkeys.

The antischistosomal activity of oral doses of amoscanate (4-isothiocyanato-4'-nitrodiphenylamine) was determined in infected Cebus apella (capuchin monkeys) and Macaca mulatta (rhesus monkeys). In C. apella infected with Schistosoma japonicum or S. mansoni an initial dose of 10 mg/kg body weight did not alter fecal egg counts, but a subsequent dose of 25 mg/kg markedly reduced both egg counts and worm burdens; in animals infected with S. haematobium, a single dose of 25 mg/kg of amoscanate was similarly effective. Comparable schistosomicidal effects were also produced in S. japonicum- and S. mansoni-infected M. mulatta by single oral doses of 20 and 35 mg/kg, respectively. In both C. apella and M. mulatta the coadministration of single oral doses of 50 or 75 mg/kg of erythromycin attenuated the appearance of mutagenic metabolites of amoscanate in the urine but did not interfere with the antischistosomal action of amoscanate. In non-infected monkeys single oral doses of 75 mg/kg of amoscanate with or without erythromycin (50 mg/kg in C. apella or 75 mg/kg in M. mulatta) did not cause any major organ toxicity as revealed by gross and histopathologic examination, hematology, blood chemistry, electrocardiograms and urinalysis. The data indicate that in C. apella and M. mulatta, amoscanate is a relatively non-toxic antischistosomal agent effective orally against a broad spectrum of schistosome species.

Aniline Compounds↗
PubMed1982

An epidemiological investigation of health risks related to solid waste salvage and recycling in an Egyptian community.

This is the first report of an epidemiological cross-sectional study of solid waste scavengers, called Zabaline, in Egypt. The Zabaline communities provide an important solid waste collection service throughout Egypt's urban sector. Their economic viability depends entirely on salvaging solid waste for recycling. Intestinal parasites were common among the Zabaline examined; 48% were found with one or more protozoan or helminth infections. Either Schistosoma haematobium or S. mansoni or both infections were found in 19% of the sample although there was an apparent lack of a local transmission focus. Ascaris lumbricoides was the most frequently seen parasite (26.0%) and Entamoeba histolytica was seen infrequently (1.6%). Physical hazards of sorting solid waste was assessed and general illness occurring during the previous month recorded. Estimates of infant mortality showed elevated measures (IMR = 205/1000). The results indicate a need for the improvement of environmental conditions and health care in the Zabaline community and suggest that other similar scavenger groups may be at risk as well.

Adolescent↗
PubMed1978

Schistosoma mekongi sp. n. from man and animals, compared with four geographic strains of Schistosoma japonicum.

Schistosoma mekongi sp. n. is described from man and animals in Cambodia. It is compared to 4 geographic strains of Schistosoma japonicum. It differs from S. japonicum in the size of embryonated eggs, in the length of the prepatent peroid in the mammalian host, and in its utilization of a different snail host. The relative usefulness of conventional morphologic criteria in the differentiation of Asian schistosomes is discussed.

Animals↗
PubMed1975

Effects of portacaval shunting on Schistosoma japonicum infection in chimpanzees: dissociation of pipe-stem fibrosis and glomerulopathy.

Eight of 10 young chimpanzees were infected with the Japanese strain of Schistosoma japonicum. In 6 of these, and in 1 normal chimpanzee, a surgical end-to-side portacaval shunt was constructed during the 8th week of infection. One additional infected chimpanzee was treated successfully with the nitrovinylfuran, SQ 18,506. In the four animals surviving both infection and shunting hepatic portal fibrosis was either absent or mild. In the 7-month survivors and in the drug-treated control animals there was evidence of healed portal endophlebitis and arterialization, but no active schistosomal liver lesion was found. Nevertheless, three of these animals showed variable degrees of active schistosomal glomerulopathy, similar to that seen in the unshunted infected control and to that described in earlier studies. There was a shift of the egg burden from the liver to the lungs, as well as evidence that the number of surviving adult worms had decreased following portacaval shunting. These observations sugggest that schistosomal nephropathy in chimpanzees is more closely related to infection intensity per se than to the degree of liver damage caused by infection.

Animals↗