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Biomedical subjects

S Sivanandam

Publications and source records attributed to S Sivanandam.

At least 19 recordsLinked to original sources
PubMed1999

Field's stain--a rapid staining method for Acanthamoeba spp.

Acanthamoeba sp. is a free-living amoeba known to cause chronic central nervous system infection or eye infection in humans. Many cases remain undetected for want of a good detection system. We report for the first time a rapid staining method to facilitate the identification of Acanthamoeba sp. using the modified Field's staining technique. A. castellanii, which was used in the present experiment, is maintained in our laboratory in mycological peptone medium (Gibco). The cultures were pooled together and smears were made on glass slides for staining purposes. Different types of stains such as Field's stain, modified Field's stain, Wright's stain, Giemsa stain, Ziehl-Neelsen stain, and trichrome stain were used to determine the best stain for the identification of this amoeba. The concentration of various stains and the duration of staining were varied to provide the best color and contrast for each stain. Acanthamoeba was also obtained from the brain of experimentally infected mice and was stained with various stains as mentioned above to determine the best stain for use in identifying the presence of this parasite in experimentally infected animals. The modified Field's stain gives a very good color contrast as compared with other stains. Furthermore, it takes only 20 s to be carried out using the least number of reagents, making it suitable for both laboratory and field use.

Acanthamoeba↗
PubMed1977

Experimental Brugia malayi infections in the rhesus monkey.

Twenty-eight rhesus monkeys in 3 groups were exposed to single (Group I), double (Group II), and multiple (Group III) inoculations with B. malayi infective larvae. Infections were monitored by microfilarial and blood counts, selected biochemical tests, IFA responses, and records of body temperature and lymphadenopathy before and/or after treatment with DEC. As a whole, the highest microfilaraemia levels were observed in Group II and lowest in Group III monkeys. Eosinophilia was a common occurrence but reached the highest mean levels in Group III. Intermittent fevers and lymph node enlargements were observed in all groups of monkeys and the occurrence of these appeared to be correlated. No definite pattern of antibody production was discernable among groups, but an inverse relationship existed between microfilaraemia and detectable microfilarial antibodies. Treatment with DEC produced a microfilaraemia-taxic effect within the initial half hour and responses to treatment varied according to individuals. Although post-treatment reinfection appeared to cause lymphoid responses and tissue eosinophilia, no substantial resistance to reinfection was observed.

Aedes↗
PubMed1976

Experimental attempts to induce ocular infection in cats with subperiodic Brugia malayi.

In an attempt to determine whether the finding of human ocular lesions due to B. malayi was due to the site of entry of the infective larvae, cats were infected via ocular instillation, subconjunctival inoculation, subcutaneous inoculation around and infective mosquito bites over the eyes. Although no conjunctival lesion was seen patent infections were produced via ocular instillation, subconjunctival and subcutaneous inoculation of infective larvae. Adult worms were also recovered from periorbital tissues. Adult worms were localized mainly in the lymphatic system of the head and neck regions of the cat. The results show that the conjunctival lesions seen in humans could be due to the site of bite of the mosquito and thus the entry of the infective larvae.

Aedes↗
PubMed1975

Experimental infection of Rattus sabanus and Rattus muelleri with subperiodic Brugia malayi.

R. sabanus and R. muelleri are very common in the lowland forests of Malaysia. In nature they are infected with Breinlia sp. and D. ramachandrani. In an attempt to determine whether they are also susceptible to subperiodic B. malayi and thereby being potential reservoirs of infection of the disease, 24 R. muelleri and 17 R. sabanus were experimentally infected with the parasite. Results show that although they can support the full development of the parasite, they are poor hosts. This confirms the observation that in Malaysia natural infection of Rattus spp. with the parasite has not been seen. These rats therefore are probably not important in the zoonotic transmission of subperiodic B. malayi in Malaysia.

Animals↗