Evaluation of the mutagenic effects of SV40 in mouse, hamster, and mouse-human hybrid cells

We have examined the ability of SV40 to induce changes in drug or temperature resistance in mouse, hamster, and mouse-human hybrid cells. SV40 induced a substantial increase of cells resistant to 5-bromodeoxyuridine + trifluorothymidine in Balb/c 3T3 cells and induced an increase of hybrid cells resistant to 6-thioguanine. SV40 was found to be nonmutagenic or weakly mutagenic in other test systems. The 3T3 cells were T-antigen positive, exhibited a marked reduction in TK activity, were heterogeneous for [ 3 H]BrdU incorporation by autoradiography, and exhibited instability of the drug-resistance phenotype, suggesting that SV40 may be inducing resistance by an epigenetic process. SV40-induced 6-thioguanine resistance in the hybrids appears to occur predominantly by chromosome loss.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45539/1/11188_2005_Article_BF01233058.pd

Untersuchungen über die Wirksamkeit der Paramunitatsinducer PIND-AVI und PIND-ORF als Strahlenschutzsubstanzen.

A significant reduction of mortality after lethal irradiation (7,8 and 9 Gy X-ray total-body irradiation) was achieved by continuous therapeutic subcutaneous application of the biologic inducers PIND-AVI and PIND-ORF. This was obtained by a stimulation of the investigated spleen parameters and a stimulation of leucocytes and phagocytosis. The inducers had no significant influence on the radiogenic reduction of blood cells and bone marrow cells, of the relative spleen and thymus weight and of the DNA and protein level of spleen and thymus. The regeneration of blood leucocytes (preponderantly by PIND-AVI) and of the spleen (preponderantly by PIND-ORF) was accelerated, but not the thymus regeneration which was already rather low. The leucocyte phagocytosis which increased generally after irradiation was markedly stimulated by paramunization. This stimulation was also observed after a latent time in animals submitted to sham irradiation. Its temporal appearance and its quantitative and qualitative properties corresponded to the effects of inducers after X-ray irradiation. Both inducers were found to be harmless in all experiments

Untersuchungen zur Hepatotoxizitaet, zum Wirkungsmechanismus, zur chemischen und physikochemischen Stabilitaet und oralen Anwendbarkeit der organischen Strahlenschutzsubstanzen WR 638 und WR 2721 sowie ihrer Polymerverbindungen Zwischenbericht. Berichtszeitraum: 7.2.1983 - 30.4.1984. Abschlussdatum: 30.5.1985

TIB: RN 3603 (85-1) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Effect of the growth promoter avilamycin on emergence and persistence of antimicrobial resistance in enteric bacteria in the pig

Aim: To assess the effect of the growth promoter avilamycin on emergence and persistence of resistance in enteric bacteria in the pig. Methods and Results: Pigs ( treated with avilamycin for 3 months and controls) were challenged with multiresistant Salmonella Typhimurium DT104 and faecal counts were performed for enterococci, Escherichia coli, S. Typhimurium and Campylobacter ( before, during and 5 weeks post-treatment). Representative isolates were tested for antibiotic resistance and for the presence of resistance genes. Avilamycin-resistant Enterococci faecalis (speciated by PCR) were isolated from the treated pigs and continued to be detected for the first week after treatment had ceased. The avilamycin- resistance gene was characterized by PCR as the emtA gene and speciation by PCR. MIC profiling confirmed that more than one strain of Ent. faecalis carried this gene. There was no evidence of increased antimicrobial resistance in the E. coli, Salmonella and Campylobacter populations, although there was a higher incidence of tetB positive E. coli in the treated pigs than the controls. Conclusion: Although avilamycin selects for resistance in the native enterococci population of the pig, no resistant isolates were detected beyond 1 week post-treatment. This suggests that resistant isolates were unable to persist once selective pressure was removed and were out-competed by the sensitive microflora. Significance and Impact of the Study: Our data suggest the risk of resistant isolates becoming carcass contaminants and infecting humans could be minimized by introducing a withdrawal period after using avilamycin and prior to slaughter