Biomedical subjects
M S Legator
Publications and source records attributed to M S Legator.
Effect of aflatoxin B1 on the deoxyribonucleic acid polymerase of Escherichia coli.
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The influence of contaminants on the mutagenic activity of dibromochloropropane (DBCP).
This study investigates the possible role of impurities in dibromochloropropane in inducing mutations, and discusses the importance of contaminants in mutagenicity and carcinogenicity testing. A technical grade sample and a pure sample of DBCP (no epichlorohydrin added) were assayed in Salmonella typhimurium TA1535, with and without S-9 activation, using agar overlay procedures and dessicator procedures. Assays performed with both technical and pure DBCP without metabolic activation resulted respectively in an increase in revertants with increasing dose (0-1600 microgram/plate) when the technical grade was tested, and no substantial increase in revertants over the same dose range when the pure DBCP was tested. Distillation of technical grade DBCP yielded an initial fraction containing high amounts of epichlorohydrin (verified by GC-MS) which was highly mutagenic. The amount of epichlorohydrin in the technical DBCP sample was calculated for each dose level tested, and the number of revertants obtained in tests of the technical DBCP sample could be attributed solely to the calculated amount of epichlorohydrin in each test dose. Tests of pure and technical DBCP using a dessicator technique produced a similar differential between the technical and pure compounds in mutagenicity. Activation of both technical and pure DBCP with S-9 from Aroclor pre-treated rats resulted in high mutagenic responses, of equal magnitude, from both preparations.
Active avoidance behavior in the F1 progeny of male rats exposed to cyclophosphamide prior to fertilization.
The acquisition and extinction of a one-way active avoidance task was studied in 30 day old F1 progeny of male rats previously exposed to either acute or chronic treatment with cyclophosphamide (CP) prior to breeding with normal females. Chronic treatment (10 mg/kg/day x 5 days x 5 weeks) was given to adult F344 males followed by subsequent breeding with normal females (CP-S). Separate groups of males were given a single CP injection (10 mg/kg) and breeding with normal females was done at 7-9, 14-16 and 28-30 days following the CP treatment. F1 progeny of males exposed to chronic CP or to a single CP treatment when bred 7-9 (females only) and 14-16 days post exposure (males and females) took significantly longer to reach the criterion for extinction. These progeny also responded significantly faster during extinction than progeny of the saline treated males. These findings support our earlier evidence of behavioral anomalies induced in the F1 progeny of male rats exposed to CP prior to breeding and that this effect reflects damage in post-meiotic germ cells.