Induction of squamous carcinoma of the lung and of the stomach and oesophagus by diazomethane and N-methyl-N-nitroso-urethane, respectively.
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
The major protein-rich foods, particularly muscle meats, contain part-per-billion quantities of potent mutagens formed by frying or broiling to a well-done state. Related mutagens are formed by pyrolysis of amino acids or proteins and in heated model systems. The thermic mutagens so far identified are heterocyclic aromatic amines of aminoimidazo-azaarene (AIA) and aminocarboline classes. The chemicals require activation by enzymes to form metabolites reactive with nucleic acids. These thermic mutagens, and numerous synthetic congeners, exhibit an enormous range of potency as frameshift mutagens in the Ames/Salmonella assay. However, structural variations are nominal within the two classes. Structural parameters that appeared relevant to determining potency were selected for 38 AIAs and 23 amino-carbolines. For the AIA class these were: the number of fused rings, the number of heteroatoms in Rings 2 and 3, methyl substitution on imidazo ring nitrogen atoms, and methyl substitution on ring carbon atoms. For the amino-carboline class the structural parameters were: the position of the pyridine-type nitrogen atom in Ring 1, the substitution position of the exocyclic amino group on Ring 1, and methyl substitution on ring carbon atoms. These structural parameters may influence mutagenic potency in the following ways. 1) Electronic or steric effects may determine the reactivity and stability of the ultimate mutagenic metabolite. Optimal balance of reactivity and lifetime of this transient intermediate may be required for access to and reaction with nuclear DNA to cause mutations. 2) Substitution on the rings may block detoxication reactions. The structural parameters identified should prove useful in predicting the mutagenicity of untested compounds of these types.
Pelagite of East Pacific Ocean as a low-price, very high reserve photocatalyst, has been successfully used for the first time to realize total degradation and decoloration of methyl orange within 120 min through photocatalysis. The photocatalysis and degradation performance of pelagite for methyl orange under the effect of various factors has been studied. Results show that pelagite has satisfactory photocatalysis effect in degradation of organic compounds.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
BACKGROUND: In spite of sporadic data pointing at the role of textile dyes as important contact allergens, only few studies have addressed the issue of the frequency of sensitization to textile dyes in populations of consecutive patients. OBJECTIVE: The purpose of this study was to evaluate the prevalence of sensitization to disperse dyes, to investigate cross reactivity between azo dyes and para-amino compounds, to describe azo-dye-positive patients, and to study the correlation between clinical aspects and sensitization to different disperse dyes. METHODS: From January 1996 to December 2000, 6,478 consecutive patients were tested with 7 textile dyes: Disperse Blue 124, Disperse Blue 106, Disperse Red 1, Disperse Yellow 3, Disperse Orange 3 (DO3), para-aminoazobenzene (PAAB), and para-dimethylaminoazobenzene (PDAAB). RESULTS: Of the above, 437 patients were allergic. The most common sensitizers were Disperse Blue (DB) dyes and Disperse Orange 3. Both the clinical aspect and the localization of the lesions were unusual in a fair percentage of cases, especially in DB-positive subjects. Involvement of skin folds was observed in 27% of disperse dye-positive patients, mainly comprising DB-sensitive women. Cross-reactivity between azo-dyes and paraphenylenediamine (PPD) was frequent in DO3-, PAAB-, and PDAAB-positive subjects, but not in DB-allergic ones. Moreover, cross reactions between DB106 and DB124 were observed in 59% of DB106- and/or DB124-positive patients. CONCLUSIONS: The frequency of disperse dye allergy is higher than generally estimated. Further studies, using routine diagnostic testing with disperse dyes, are needed to investigate whether this increasing trend is present outside of Europe.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Some aryl-N(O) = N-X and heteroaryl-N(O) = N-CN compounds were synthetized and tested against a culture of HeLa cells. The results obtained show that the - N(O) = N beta CN function, a new cytostatic group, is useful in the design of potential antitumoral compounds.
Explore the source record for details and available documents.
Horseradish peroxidase (HRP) is known to degrade certain recalcitrant organic compounds such as phenol and substituted phenols. Here, for the first time we have shown HRP to be effective in degrading and precipitating industrially important azo dyes. For Remazol blue, the enzyme activity was found to be far better at pH 2.5 than at neutral pH. In addition, Remazol blue acts as a strong competitive inhibitor of HRP at neutral pH. Horseradish peroxidase shows broad substrate specificity toward a variety of azo dyes. Kinetic constants (K(m)(app) and V(max)(app)) for two different dyes have been determined. In addition to providing a systematic analysis of the potential of HRP in degradation of dyes, this study opens up a new area on exploration of commercial dyes as inhibitors of enzymes. 2001 John Wiley & Sons, Inc.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.