Uridine labeling of human lymphocytes: Differential uptake by T and B cells

Human peripheral blood lymphocytes were labeled with [³H]uridine and separated into immunoglobulin (Ig)-positive-enriched and Ig-negative populations by rosetting and Ficoll sedimentation. The Ig-negative (T cell-rich) fraction was found to be more heavily labeled than the B cell-enriched population, in agreement with previous results in rats. Combined autoradiography and rosetting confirmed the differential uridine labeling of T and B cells. Incorporation of cytidine and adenosine by T and B cell-enriched populations showed similar but less dramatic differential labeling.     

Overview of the genetic toxicity of caprolactam and benzoin

DNA binding in vitro was measured with 2-amino-3- methylimidazo(4,5-f)[5-3H]quinoline (3H-IQ) in the presence of S9 and microsomes from Wistar rat liver. DNA binding of 3H-IQ was catalyzed by both microsomes and S9 and was increased 5-fold in Aroclor (PCB)-pretreated animals. DNA binding was reduced by the specific inhibitor of sulfotransferase 2,6-dichloro-4-nitrophenol and slightly increased by 3'-phosphoadenosine 5'-phosphosulfate. The incubation of IQ in media with increasing concentrations of sulfate produced a modest dose-dependent increase in DNA binding. Liver S9 obtained from rats which had been administered 1% sulfite in drinking water catalyzed a higher binding of IQ to DNA, and this effect was inhibited by pentachlorophenol. The data demonstrate that sulfotransferase has a role in the activation of IQ and that variations in the activity of this enzyme induced by dietary changes may vary the genotoxic activity of IQ.     

Human prothymosin α: Purification of a highly acidic nuclear protein by means of a phenol extraction

Human prothymosin a, virtually alone among proteins, is recovered from the aqueous phase of phenolextracted cell lysates prepared from human myeloma cells or COS cells that were transfected with the human prothymosin a gene. This observation forms the basis for purification of the protein to homogeneity in two steps—phenol extraction followed by electrophoresis steps—phenol extraction followed by electrophoresis in sodium dodecyl sulfate polyacrylamide gels to remove residual contaminants consisting chiefly of carbohydrate and RNA.