Biomedical subjects
Publications and source records attributed to S R Joshi.
An immediate haemolytic transfusion reaction was investigated in a patient with intestinal cancer. The causative antibody was directed against a high-frequency antigen Inb that was presumably produced as a result of pregnancies. This is the first case of a severe transfusion reaction due to this alloantibody.
Studies of radioactivity in the Laurentian Great Lakes are reviewed to evaluate the impact of radionuclide dissemination on the world's foremost freshwater aquatic ecosystem. The status of radiologically-degraded areas is also reported. Significant amounts of radioactivity are stored in the basin, which has numerous nuclear reactors as well as uranium mine waste areas. The prevailing low levels of artificially-produced radionuclides, arising largely from previous fallout inputs, provide very little radiation dose to the area residents consuming lake water. The interlake transport of radionuclides is adequately described by existing models, though some refinement of the source term is needed. Revised estimates of fallout over each lake are given, but no data are available to estimate drainage basin contributions. Only limited information is available on the dispersal of radioactive pollutants. The influence of chemical parameters on radionuclide cycling has been extensively investigated in Lake Michigan and, to a lesser degree, in Lake Ontario. The need for developing a radiological objective for fish becomes apparent from an assessment of the very few data collected thus far on the biological and dosimetric aspects. Several research and monitoring needs are also identified.
When blood samples from 5,864 healthy Indian blood donors were tested with anti-I, seven samples failed to react or reacted only weakly. Further studies with a number of anti-I and anti-i sera suggested that these samples had the phenotype I-i- and reacted weakly with anti-IT. In one family, the I-i- phenotype was present in three generations.
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Methyl(acetoxymethyl)nitrosamine (DMN-OAc) was synthesized and tested for toxicity and carcinogenicity in rats to test the hypothesis that alpha-hydroxylation is required for metabolic activation of dimethylnitrosamine (DMN) to a reactive, proximate carcinogen. The acute median lethal doses (LD50) of DMN-OAc and DMN injected ip into 5-week-old male Sprague-Dawley (Charles River (CD) rats were determined to be 0.19 and 0.59 mmole/kg body weight or 25 mg DMN-OAc/kg and 44 mg DMN/kg body weight, respectively. Single ip injections of one-half the LD50 DMN-OAc (13 mg/kg body weight) in 5-week-old rats of both sexes resulted in a high incidence of epithelial tumors of the intestinal tract. Mean survival times for rats with intestinal tumors were 353 days for males and 433 days for females. Tumors were rarely found at other sites. DMN at equivalent toxic (one-half the LD50, 22 mg/kg) and molar (= one-sixth LD50, 7.0 mg/kg) dose levels, yielded (as expected) tumors of kidneys, lungs, and occasionally other organs, but at a much lower incidence. The finding of the potent carcinogenicity of DMN-OAc supported the postulate that alpha-hydroxylation of DMN in vivo generates a proximate carcinogen.
A population genetic study among the Kota of the Nilgiri Hills, South India, involved tests for abnormal haemoglobins, 5 red cell antigen systems, 4 serum protein and 13 red cell enzymes systems. Twelve systems are invariant in the Kota. The most distinctive characteristics are extremely low frequency of the A1 gene and complete absence of A2 in the ABO system, r(cde) in the Rh system, LDH cal-1 among the enzyme systems as well as absence of abnormal haemoglobins. A comparison of gene frequencies in those systems, which show variation, suggests that the Kota are more similar to the Toda than to any other tribal or caste population of the area. Genetic distance as well principal component analysis also reveals that the Toda and Kota are close to each other, in agreement with tradition.
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A total of nearly 1,000 persons belonging to a number of caste, religious and tribal groupings in Kerala and the Nilgiri Hills of South India have been tested for genetic variation in 4 blood group, 5 serum protein and 17 enzyme systems as well as haemoglobin. The distribution of blood groups, serum protein and enzyme groups is similar to that reported for other South Indian populations. Abnormal haemoglobins were detected in several populations. Abnormal haemoglobins were detected in several populations, HbS being present in more than 20% of the Irula and Kurumba in the Nilgiri Hills. In the Kerala populations there were 4 examples of Hb AD and 1 of Hb AE. Genetic distance estimates using the gene frequency data indicate that the closest groups are the Nayar and Izhava and the Brahmin and Nayar. The tribal populations are approximately twice as far from the Nayar as they are from the Izhava. The Todas of the Nilgiri Hills are somewhat closer to the Brahmin of Kerala than they are to the other tribal populations.
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