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Biomedical subjects

J H Cross

Publications and source records attributed to J H Cross.

At least 73 records · Page 4Linked to original sources
PubMed1990

Rapid diagnosis of Brugia malayi and Wuchereria bancrofti filariasis by an acridine orange/microhematocrit tube technique.

A microhematocrit tube technique for diagnosis of human filariasis has been previously described. A system incorporating heparin, EDTA, and acridine orange into a microhematocrit tube (Quantitative Blood Count, QBC) has been commercially developed for the quantitation of blood counts and has been used for the diagnosis of malaria. We evaluated this test for its usefulness in the diagnosis of filariasis. Upon centrifugation, the parasites were concentrated in the area of the buffy coat and could be observed through the wall of the tube. The parasites were concentrated further by a plastic float that expands the buffy coat and confines the parasites to the periphery of the tube. Acridine orange stains the DNA of the parasite, and morphologic characteristics can be examined by fluorescence microscopy. The terminal and subterminal nuclei and long cephalic space of Brugia malayi, as well as the short cephalic space and caudal nuclei of Wuchereria bancrofti, were easily recognized and differentiated from each other. Microfilariae were detected in samples diluted to a level of approximately 50/ml.

Acridine Orange↗
PubMed1989

The serological response of pigs experimentally infected with a species of Taenia from Taiwan.

An enzyme-linked immunosorbent assay (ELISA) for the detection of antibody in pigs infected with a possibly new species of Taenia isolated in Taiwan is described. The test antigen ThFAS was fractionated from the cyst fluid of a heterologous cestode Taenia hydatigena. In lightly infected pigs (less than or equal to 4 recovered cysts at necropsy 17 weeks post-inoculation), antibody was detected as early as 3 weeks post-inoculation. In more heavily infected pigs (6-72 recovered cysts at necropsy 32 weeks post-inoculation), antibody was still detectable at the time of necropsy. Cysticerci were found only in the livers of the infected pigs. This ELISA should be highly useful for detecting infection of pigs with this larval cestode in regions where the presence of Taenia solium is unlikely.

Animals↗
PubMed1989

Seroepidemiology of toxoplasmosis on Taiwan and some of the offshore islands.

Over 4,000 serum specimens from various population groups on Taiwan, Lan Yu, and the Pescadores Islands were tested for antibodies to Toxoplasma gondii by use of the indirect hemagglutination test. Only 74 sera were considered to be positive at titers of 1:256 or greater. The highest prevalence rates of positive antibody titers were obtained from 335 people from Ian Yu Island; 59 (18%) were considered positive. A few (11 soldiers) positive titers were detected in sera from 2,487 Chinese Marine recruits on first bleedings and 4 found positive on a second bleeding 12-18 months later. Only a few suspected cases of toxoplasmosis have been reported from humans, yet a number of animals have been found infected with the parasite and other animals found serologically positive. These and other aspects of toxoplasmosis on Taiwan are discussed.

Antibodies, Protozoan↗
PubMed1989

Symptoms associated with diarrhoeal illness at San Lazaro Hospital, Manila in 1983 and 1984.

The clinical features associated with various agents of diarrhoeal disease were studied using 2,836 patients admitted to San Lazaro Hospital, Manila. Three general patient groups were considered including single pathogen isolations, "multiple pathogen" isolations, and "no pathogen" isolations. In general, symptoms of diarrhoeal illness were found to be non-specific. However, Shigella flexneri. Vibrio parahemolyticus, and rotavirus were significantly associated with a number of prominent symptoms and could sometimes be predictably diagnosed on clinical grounds, especially when age of the patient was considered. Clinical diagnosis cannot be considered an adequate substitute for laboratory methods; other enteric pathogens can sometimes present with the same symptoms. When appropriate laboratory testing is unavailable, as is often the case in developing countries, symptomatologic diagnosis may be of limited value for the organisms mentioned.

Acute Disease↗
PubMed1988

Biotechnological methods on the study of nematodes.

During the past several years, a great many advances have been made in obtaining a better understanding of the biology of nematode parasites. Much of the information obtained has been with the use of tools developed in the expanding field of biotechnology, or more specifically, the use of biochemistry, genetics or molecular biology. Advances are being made on speciation of parasites, their function and pathogenesis. Some nematode parasites indigenous to Southeast Asia have been studied, but much more should be done. There is a large group of parasites in Southeast Asia that could be studied. In the past, emphasis has been on human nematodes, but there are many interesting parasites of lower animals that should be investigated. Furthermore, future parasitologists must first be trained in basic parasitology and then be exposed to new technology in order to apply these tools to further our knowledge of round worms.

Animals↗
PubMed1988

Biotechnology research on cestodes in the Philippines, Malaysia, and Indonesia.

There are essentially no reports on the use of modern biotechnological methods on the study of cestode parasites in the Philippines, Indonesia or Malaysia. The only recent reports of cestode studies in these countries have been on reports of new species in animals and on prevalence rates of cestode parasites in humans; Taenia solium and cysticercosis, Taenia saginata and Hymenolepis nana, etc. Reports on the use of biotechnology has emanated from outside the area on cestodes of humans and animals, and some of these methods could be used to study cestodes in this part of the world.

Animals↗
PubMed1987

Diagnostic value of a single, pre-treatment Widal test in suspected enteric fever cases in the Philippines.

101 patients with a clinical suspicion of typhoid or paratyphoid (enteric) fever admitted to San Lazaro Hospital, Manila, Philippines, were studied by bacteriological culture of blood, rectal swab, urine and duodenal string capsule; 35 also had bacteriological culture of bone marrow aspirate. 44 of the patients were culture-confirmed as having enteric fever; the remainder were classified as non-enteric fever cases. Analysis of the pretreatment Widal agglutination titres of all patients revealed that using as a diagnostic criterion an antibody titre of greater than or equal to 1:80 to the O antigen of Salmonella typhi yielded a test specificity of 100%, although the corresponding sensitivity was only 64%. The sensitivity of the test could be increased to 80% by using different cut-off values for titres to flagellar antigens, but this concomitantly decreased the test specificity from 100 to 82%. The data indicate that a single pretreatment Widal test in suspected enteric fever cases is of definite diagnostic value, but that the results must be interpreted with caution and foreknowledge of the test's shortcomings and limitations.

Adolescent↗
PubMed1987

Public health importance of Angiostrongylus cantonensis and its relatives.

Species of Angiostrongylus are fairly common nematode parasites of a variety of small mammals, but some species - particularly A. cantonensis and A. costaricensis - are increasingly seen as human infections. The worms make use of a range of aquatic, amphibious or terrestrial gastropod molluscs as intermediate hosts, which become infected by ingestion of eggs shed in the faeces of infected mammals. Porotenic hosts, including crustaceans, amphibians and reptiles, are known for most Angiostrongylus species, and can also be a source of the infective third-stage larvae that initiate mammalian infections.

Journal Article↗
PubMed1987

Two-year survey of etiologic agents of diarrheal disease at San Lazaro Hospital, Manila, Republic of the Philippines.

The prevalence of bacterial pathogens and rotavirus in 2,908 patients with diarrhea who were admitted to San Lazaro Hospital in Manila in 1983 and 1984 was determined. One or more enteric pathogens were isolated or detected in samples from 1,698 (58.4%) patients. Isolation rates for the various enteropathogens were as follows: rotavirus, 30.6%; Shigella spp., 11.6%; Salmonella spp., 9.2%; enterotoxigenic Escherichia coli (1983 only), 7.8%; Vibrio cholerae biotype eltor, 3.8%; non-O1 V. cholerae, 2.8%; Vibrio parahaemolyticus, 1.7%; other Vibrio spp., 1.1%; Campylobacter jejuni, 3.0%; Aeromonas hydrophila, 1.3%; and Plesiomonas shigelloides 1.1%. Giardia lamblia and Entamoeba histolytica were detected in 0.6 and 0.1%, respectively, of stool samples examined. Determination of the etiologic role of isolates was complicated by one or more of the following factors: isolation of multiple enteric pathogens (302 cases); isolation of Salmonella spp., enterotoxigenic E. coli, and C. jejuni from a similar proportion of asymptomatic control patients and patients with diarrhea; and isolation of a high proportion of certain pathogens (especially Salmonella spp.) only from enrichment broth, suggesting infection with a small number of organisms. Isolation of V. cholerae eltor was seasonal, with the majority of cases occurring in the rainy months. In addition, the number of patients with diarrhea increased with the onset of the monsoon rains and peaked during the months of maximum rainfall. Rotavirus infection occurred in both children and adults throughout the year and was the most frequently identified cause of diarrhea in children under 5 years of age. Shigella spp. were the most common agents of diarrhea in adults.

Adolescent↗
PubMed1987

Development of Brugia malayi in Mongolian gerbils previously exposed to Wuchereria bancrofti.

Twelve Mongolian gerbils, Meriones unguiculatus, were infected with 100 third-stage larvae of Wuchereria bancrofti. One month later these animals, along with 4 control animals, were given 100 third-stage larvae of Brugia malayi. Eleven of the 12 experimental animals and the 4 controls survived, and 8 of the experimental animals and all of the controls demonstrated microfilaremia after 3 months. The animals were killed at 6-months post-infection and examined for parasites. One W. bancrofti larva was found in one of the experimental animals, and 15% of the B. malayi given were recovered as adults from the testes, viscera, and carcass. Thirty-eight percent of the worms given to the controls were recovered from the testes, viscera, and pelt. The worms from the experimental animals also appeared to be smaller. This study suggests that gerbils are able to develop partial resistance to Brugia malayi following a previous infection with Wuchereria bancrofti.

Animals↗
PubMed1987

Albendazole in the treatment of intestinal capillariasis.

Albendazole or Zentel a benzimidazole derivative, was used to treat intestinal capillariasis in hospitalized patients seen in Northern Luzon in the Philippines. In initial studies, four patients responded satisfactorily to the drug in dosages of 400 mg/day in divided doses for 20 days. This is the same dosage used for mebendazole, which has been the drug of choice in treating the parasitosis. In further studies, 16 patients with Capillaria philippinensis, were treated with 400 mg/day of the drug for 10 days, and 15 were completely cured. The one treatment failure was found to be passing eggs of the parasite three months later, and was retreated with the standard mebendazole regimen of 400 mg/day for 20 days. Side effects attributed to albendazole were not reported in any of the patients. Albendazole, 400 mg/day in two divided doses, is now the recommended drug of choice in Northern Luzon in the Philippines.

Adolescent↗
PubMed1986

Praziquantel in treatment of cerebral schistosomiasis.

The effectiveness of standard single-day praziquantel treatment (60 mg/kg) was prospectively evaluated in nine patients with seizures caused by cerebral Schistosoma japonicum infection. Eight patients were cured when discharged from the study, an average of 6 months after receiving praziquantel. They were seizure-free in the absence of anticonvulsants, their electroencephalograms were normal, and no major abnormalities could be detected on neurological examination. Serial computed tomography scanning revealed rapid dissipation of cerebral oedema and complete or near-complete resolution of mass lesions. No serious adverse effects of praziquantel were encountered. The ninth patient was not cured but improved greatly in the months after treatment. Thus, single-day treatment with praziquantel is safe and effective in cerebral schistosomiasis.

Adult↗
PubMed1986

HBsAG and HBeAG markers among pregnant women in Manila, Philippines.

The sera of 5,684 pregnant women were tested for HBsAG and 432 (7.6%) were found positive. Positive HBsAG sera were then tested for the e antigen and of 413 tested, 115 or 27.8% were positive. The over-all prevalence rate of e antigen was 2.03%. All women were asymptomatic. Six of 13 HBsAG-HBeAg-positive mothers delivered infants who became HBsAg-positive within two years of age for a rate of 46%. The findings support earlier studies on the importance of the e antigen as an index of perinatal transmission. Also, they support evidence of unusually high rates of transmission among Asian ethnic groups.

Adolescent↗