Aryl hydrocarbon hydroxylase is present and is inducible in mouse skin. 7,8-Benzoflavone, an inhibitor of the enzyme, markedly inhibits tumorigenesis by 7,12-dimethylbenz(a)anthracene, but has either no effect on or stimulates benzo(a)pyrene tumorigenesis. Thus, the role of aryl hydrocarbon hydroxylase appears highly specific for each polycyclic hydrocarbon, in respect to detoxification and/or ...

Benzo(a)pyrene injection increased the phospholipid content in membranes of rat liver mitochondria and microsomes. There was a large relative increase of phosphatidylcholine, especially in microsomes, as compared with normal liver. The quantity of phosphatidylethanolamine seemed not be affected and the other phospholipid classes decreased. In vivo [U-14C]glycerol incorporation into phospholipid...

In lung and liver cancers, p53 mutations are mostly G:C to T:A transversions. This type of mutation is known to be induced by benzo(a)pyrene and aflatoxin B1 which are associated with the etiology of lung and liver cancers, respectively. Using a novel assay based on DNA polymerase fingerprint analysis, we identified p53 nucleotides targeted by these carcinogens. Thirteen of 14 nucleotide residu...

The potential of polycyclic aromatic hydrocarbons (PAHs) to modulate microsomal epoxide hydrolase activity, determined using benzo[a]pyrene 5-oxide as substrate, in human liver, was evaluated and compared to rat liver. Precision-cut liver slices prepared from fresh human liver were incubated with six structurally diverse PAHs, at a range of concentrations, for 24h. Of the six PAHs studied, benz...

A maximal degradation rate (76%) was obtained when Polyporus sp. S133 was cultured with 0.05% of tween 80, as compared to just 35% degradation in non-supplemented cultures. When fungus Polyporus sp. S133 was grown in presence of shitake’s nutrient, the degradation rate increased up to 69% as compared to just 56 and 40% degradation in glucose and polypeptone supplemented cultures. One metabolite...

The present investigation shows the effect of vitamin A deficiency on the initiation and postinitiation phases of benzo(a)pyrene-induced lung carcinogenesis in male Wistar rats. Lung tumours were induced by giving three intratracheal instillations, one week apart, of 10mg benzo(a)pyrene per instillation. Maximum tumour incidence (100%) and tumour burden per rat was found in rats which were kept...

Seven types of carbon black used in type production were subjected to hygienic evaluation. The coal tar pitch volatiles (CTPVs), toluene solubles, were determined by the gravimetric method and benzo/a/pyrene by HPLC with a spectrophotometric detector. Toluene solubles were found to amount to 0.12-0.25% (by weight). Benzo/a/pyrene (1.44-3.07 ppm) was detected in five out of the seven carbon blac...

Isolated tracheas were incubated in vitro in the presence of tritiated benzo[a]pyrene. Highly purified DNA was isolated from the epithelial cells of these tracheas and was found to contain bound BP-3H. If tracheas were obtained from hamsters previously treated intratracheally with benzo[a]pyrene plus Fe2O3, this binding was enhanced. Incuba tion of tracheas in the presence of 7,8-benzoflavone o...

Directly active mutagens are formed on exposure of the promutagen benzo[a]pyrene to gaseous pollutants in smog. In simulated atmospheres containing 1 part per million nitrogen dioxide and traces of nitric acid, directly mutagenic nitro derivatives are readily formed from both benzo[a]pyrene and perylene, a non-mutagen in the Ames reversion assay. Possible formation of direct mutagens by such re...