The distribution of electrophoretic variants in 4 serum protein and 12 red cell enzyme systems has been determined among nearly 500 persons belonging to various castes in North India. No electrophoretic variants were found for transferrin or for the enzyme systems malate dehydrogenase, peptidase B, ‘oxidase’, phosphoglycerate kinase and phosphoglucomutase-locus 2. Two persons with abnormal albumins were detected, and the slower moving band has been identified provisionally as albumin Gainsville. One person with an unusual caeruloplasmin was found also, and this has been identified provisionally as Cp ANigera. In the haptoglobin system the overall frequency of Hp2 = 0.20 is similar to that found previously in North India. The lowest Hp2frequency (0.12) was found among the Scheduled Castes. The PHsc gene in the red cell acid phosphatase system was of low frequency (0.005) as also was the PGDC allele (0.02) in the 6-phosphogluconate dehydrogenase system. Three phenotypes were present in the adenylate kinase system, and the AK2 gene frequency of 0.09 is among the highest values reported so far. For phosphoglucomutase-locus 1, in addition to the common alleles PGM11 and PGM21 there were several examples of the rarer PGM31, PGM61 and PGM71 alleles. PGM11 frequencies varied from 0.63 to 0.79 in different caste groups. Seven examples of heterozygotes for the Calcutta-1 variant of lactate dehydrogenase were detected giving an overall frequency of LDHCal. = 0.007. A single case of Pep A 2–1 was observed in the peptidase A system. Three other enzyme systems showing electrophoretic variation had been studied previously only on Indians living in England. In the present study 3 phenotypes were present for adenosine deaminase, and the ADA2 allele had a range of frequency of 0.06 to 0.20. The latter figure, for the Arora, is the highest frequency so far reported for this allele. Only rare variants were present in the phosphohexose isomerase and NADH diaphorase systems. There were 6 PHI 3–1, 1 PHI 5–1 and 1 PHI 9–1 phenotypes in a total of 490 samples tested. Half of these variants were found among the 83 persons belonging to the Scheduled Castes. In the diaphorase system there were 6 2–1 and 1 4–1 phenotypes distributed between the caste groups.
The following guidelines were adopted by an Ad Hoc Committee convened at the Fourth International Workshop on the Fragile X Syndrome and X-Linked Mental Retardation to establish minimum cytogenetic standards for the preparation and analysis of the fragile X chromosome. The intention of the committee was to develop and provide practical standards for the routine cytogenetic detection of the fragile X. The guidelines describe reasonable criteria for effective tissue culture methods for eliciting the Xq27.3 fragile site in vitro and for the analysis of such chromosome preparations.
A large number of drugs have been introduced into man's environment in recent years, many of which have been shown to have mutagenic, teratogenic and carcinogenic effects. Keeping in view the potential hazardous effects of drugs and chemicals, it is desirable to test new drugs for their genotoxic effects prior to widespread use. 1 In the present investigation genetic effects of ampicillin and carbenicillin were studied in vitro in human lymphocytes using a number of end-points. 2 These drugs were added at a range of concentrations and times during a 72h culture period. Concentrations corresponding to the plasma level after receiving therapeutic doses as well as concentrations higher than the plasma levels were examined. 3 Neither drug affected the frequency of chromosome aberrations, satellite associations, mitotic index and cell turnover rate at plasma level concentrations. However, all these parameters were affected at higher concentrations. 4 The frequency of SCEs was not increased with both the drugs irrespective of the concentrations or durations of treatment, suggesting that the mechanisms leading to the formation of SCEs and chromosome aberrations are different. 5 Both ampicillin and carbenicillin were genetically non-toxic for the end points measured and non-clastogenic in vitro at therapeutic doses. However, previous studies have shown ampicillin to be clastogenic in vivo. 6 For evaluation of genetic toxicity, drugs should be tested both in vitro and in vivo.
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