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Biomedical subjects

S K Seah

Publications and source records attributed to S K Seah.

At least 37 records · Page 2Linked to original sources

Experimental Trypanosoma cruzi infection in rhesus monkeys 111. Electrocardiographic and histopathological findings.

In five rhesus monkeys surviving 'Peru strain' or 'strain 7' Trypanosoma cruzi infection for six to eight years, positive xenodiagnosis results and high indirect fluorescent antibody titres (4096 - 65536) persisted until the animals were killed. Abnormal electrocardiograph patterns in two monkeys (H and K) were possibly compatible with myocardial damage. Histopathological changes attributable to T. cruzi infection were minor in four monkeys but severe in one (R). In this animal, infected with what was judged previously to be the less virulent of the two T. cruzi stocks used ('strain 7'), there was severe myocarditis, with myofibre degeneration, and lesions of the oesophagus. Elevated serum levels of five enzymes were not detected in any of the chronically infected monkeys.

Animals↗

Mebendazole in the treatment of helminthiasis.

Mebendazole, a new broad-spectrum anthelmintic, was used to treat patients with nematode infections--ascariasis, trichuriasis and hookworm. The dosage for adults was 100 mg twice daily for 3 days and for children, 50 mg twice daily for 3 days. Pretreatment and post-treatment egg counts on stool specimens showed that after mebendazole there was a reduction of over 99% in egg count per gram of stool in all three types of infection. The overall cure rates for the infections were as follows: Ascaris lumbricoides, 86.8% (59/68); Trichuris trichiura, 86.0% (37/43); and hookworm, 85.7% (24/28). The drug was equally effective in light and heavy infections. No important side effect was noted with this drug. It is suggested that mebendazole is the drug of choice for trichuriasis and mixed nematode infection.

Adult↗

Experimental Trypanosoma cruzi infections in rhesus monkeys. II. The early chronic phase.

Information on the acute and early chronic phases of infection with Trypanosoma cruzi in eight rhesus monkeys is reported with particular reference to the pattern of subpatent parasitaemia and serology. Xenodiagnosis was superior to animal inoculation and blood culture in its capacity to detect subpatent parasitaemia. Each monkey showed an individual, relatively constant pattern of this not related to the nature of the inoculum. Levels of indirect fluorescent and indirect haemagglutinating antibodies remained elevated during a year of observations. One monkey died with a megaoesophagus. Another monkey after challenge with a heterologous strain by orbital inoculation failed to develop Romana's sign and showed no change in serum antibody levels or degree of xenopositivity.

Animals↗

Dogs and intestinal parasites: a public health problem.

The stools of 239 stray dogs were examined for intestinal parasites. Of the helminths found, Toxocara canis (43.5%), tapeworms (25.5%), Ascaris species (21.3%) and hookworms (12.5%) were the commonest. Of the protozoans found, Isospora species and Entamoeba coli were the most prevalent. An unusual feature of the present study was the finding of Ascaris species. The importance of the high prevalence of intestinal parasites in dogs, the close contact of humans with dogs' excreta and the possible role of this environmental pollution in the spread of human disease are discussed.

Animals↗

The use of irradiated vaccine in immunization against experimental murine toxoplasmosis.

Trophozoites from the peritoneal cavities of mice infected with the RH strain Toxoplasma gondii were given irradiation in doses of 5, 10, 15, and 20 kiloroentgens (kr). CD-1 strain mice that received intraperitoneal inoculation of trophozoites irradiated with 5 kr all died of toxoplasmosis, but the mice that received trophozoites irradiated with the higher doses all survived. The survirors that were examined were found to be free of toxoplasmic cysts. Single doses of these irradiated vaccines provided good protection to subsequent virulent challenge. This protection was 100% in the first 3 weeks after the immunization. Survivors of the first challenge were also solidly protected against a subsequent rechallenge.

Animals↗

Chemotherapy in experimental toxoplasmosis: comparison of the efficacy of trimethoprim-sulfur and pyrimethamine-sulfur combinations.

Mice infected by intraperitoneal inoculation of the RH strain of Toxoplasma gondii were treated with various drugs. Trimethoprim was found to have no effect. Sulphamethoxazole, sulphadiazine and pyrimethamine had significant therapeutic effects on the course of murine toxoplasmosis. The therapeutic efficacy of sulphamethoxazole was enhanced by the addition of trimethoprim. A pyrimethamine-sulphadiazine combination was found to be superior to a trimethoprim-sulphamethoxazole combination in the treatment of experimental murine toxoplasmosis.

Animals↗

Onchocerciasis in Canada.

The first two cases of onchocerciasis seen in Canada are reported. The patients had come from West Africa to study in Canada several months prior to admission to hospital. The presenting symptom in each case was intense pruritus. One of the patients had early ocular involvement. The diagnosis was made by means of microscopic examination of a skin snip. The subcutaneous nodule excised from one of the patients showed the adult Onchocerca volvulus. Both patients also had urinary schistosomiasis. The clinical features, laboratory findings, treatment and public health aspects of onchocerciasis are discussed.

Adult↗

Toxoplasma antibodies in immigrants from Hong Kong.

The sera of 200 Chinese adults recently immigrated to Canada from Hong Kong were examined for antibodies to Toxoplasma gondii by the indirect fluorescent antibody technique. It was found that the total incidence was 18.0%. This is significantly lower than that of the indigenous population of the same age groups in this area.

Adult↗