[Carcinogenicity test in long-term bioassay of Fermosin-yeast grown on petroleum hydrocarbons]. / Kanzerogenitäts-Test von "fermosinR'-Futterhefe, gezüchtet auf Erdölkohlenwasserstoffen, im Langzeit-Tierversuch.

To test "fermosinR'-yeast grown on petroleum hydrocarbons for carcinogenic potency the product was fed chronically at a dietary level of 15% to male and female rats (Wistar). Animals of the control group received the Institute's stock diet, similar to the yeast diet but without "fermosinR'. Feeding of "fermosinR'-diet did not affect the incidence nor the latency period nor the type of tumors compared with the control rats. Studies in mice (XVII) included two separate experiments. In the first one the dorsal skin of the animals was painted by extracts from yeast twice weekly and treated with the co-carcinogenic agent croton oil once a week. In the second experiment the mice were painted by extracts from pork of animals feed with "fermosinR'. The results obtained in rats and in mice did not reveal any evidence for carcinogenic potency of "fermosinR'-yeast.

[LD 50 and selenium concentration in the organs of rabbits following oral administration of sodium selenite and testing of the toxicity of Ursoselevit-Prämix]. / LD50 und Selenkonzentration in den Organen von Kaninchen nach oraler Applikation von Natriumselenit und Prüfung der Toxizität von Ursoselevit-Prämix

LD50/24hr was established in the first of a series of experiments on 72 rabbits for orally applied sodium selenite. The dosage was 8.62 mg/kg live weight, the confidence interval being (1 - alpha = 0.95) +/- 0.13 mg/kg. The value was four times as high following intravenous application. Complete lethality was recorded from 15 mg Na2SeO3/kg live weight within 21 hours. Thirty-six animals were involved in the second experiment of the series. They had 50 or 100 per cent Ursoselevit-Prämix (30 ppm Se) in their rations. Body mass development of the test animals was superior to that recorded from the controls in the first 50 days, after which limit the former declined strongly in a few days. Their general condition worsened. Postmortem findings, following slaughter, included catarrhal enteritis, toxic liver dystrophy, scattered pulpous tumours in the spleen, and interstitial nephritis. In the third experiment (50 per cent Ursoselevit-Prämix with 60 ppm Se in the rations), the test animals developed better than the controls during the first two months, after which point they exhibited the same clinical symptoms as those observed in the second experiment, stopped to put on weight, and eventually turned cachectic. The pathomorphological findings were identical with those obtained from the second experiment. The selenium concentrations in the organs of the test animals all were much higher than those of the controls. Their amounts in excess to base values were up to eleven times in the blood, nine times in the liver, twelve times in the kidneys, and 13 times in the muscles.