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Chromosome aberrations and sister chromatid exchanges in Chinese hamster cells exposed to various chemicals.

To evaluate its usefulness for detection of mutagenicity and oncogenicity of chemicals, the frequency of chromosome aberrations and sister chromatid exchanges (SCE) was examined in cultured Chinese hamster cells exposed to 33 kinds of chemical agents, including 2 aromatic hydrocarbons, 7 amine derivatives, 3 phenols, 6 carboxylic acid derivatives, 4 azo compounds, 7 heterocyclic compounds, and 4 other types of agents. Among them, 7 chemicals, including 5 known oncogens (N-n-butyl-N-nitrosourethan, N-methyl-N-nitrosourea, beta-propiolacton, methylazoxymethanol acetate, and propane sultone) and 2 non-oncogens (potassium sorbate and sodium benzoate) were inducers of aberrations and/or SCE, although the effective doses for the last two agents were considerably higher. The mutagenic activities estimated by chromosome aberrations were not necessarily the same for a given chemical when estimated by SCE. Slightly to moderately increased rates of SCE or aberrations were noticed among the other 26 chemicals. However, these values were usually without a clear dose relationship.

Amines

Ellipticines as potent inhibitors of microsomes-dependent chemical mutagenesis.

9-Hydroxyellipticine (9-OHE), an inhibitor of microsomal monooxygenase activities has been shown to exert a large or even complete decrease of the mutagenicity, on the Salmonella strains of a great number of compounds (aromatic amines, polycyclic aromatic hydrocarbons, fungal toxins, azo compounds, tobacco smoke condensate). 9-OHE and 9-fluoroellipticine are more potent inhibitors than ellipticine itself. The inhibitions exerted by 9-OHE are not even equalled by 10-fold higher doses of 7,8-benzoflavone (7,8-BF). There is a good correlation between these data and the interaction properties of ellipticines with microsomal cytochromes P-450.

Alkaloids

Properties of enzymes immobilized by the diazotized m-diaminobenzene method.

Some properties of a number of enzymes immobilized by the diazotized m-diaminobenzene (dDAB) method are described. The pH-activity profiles of beta-D-glucosidase, glucoamylase, peroxidase, uricase, and D-glucose oxidase were virtually unchanged on immobilization while those of catalase and dextranase were significantly altered. beta-D-Glucosidase, glucoamylase, and glucose oxidase were found to be more susceptible to denaturation on lyophilization when immobilized than in the native state; however, sorbitol had a marked protective effect in every case examined. Sorbitol was also found to exert a stabilizing effect when lyophilized immobilized preparations were stored. Immobilization marginally improved the stabilities of a number of enzymes to heating at 60 degrees at pH 8.0. The usefulness for continuous reaction of a column of glucoamylase attached to celite was established. The reuse of the solid supports was demonstrated.

Aniline Compounds

Colorimetric acetaminophen determination in pharmaceutical formulations.

Different approaches for the colorimetric determination of acetaminophen, based on its coupling with diazotized o-nitroaniline, are described. Copper(II) chelation with the coupled compound makes the method highly selective. Sensitivity is increased when the acetaminophen assay is carried out indirectly through the determination of the chelate's copper content. Optimum conditions for performing the different approaches are described. The stoichiometric balance for the reactants in the coupled compound and chelate is determined. The degree of dissociation and the instability constant are computed. The rectilinear relationship between the absorbance of the different products and the concentration of acetaminophen allows for its determination in different pharmaceutical formulations. Compared with the official method, the proposed methods give more accurate results.

Acetaminophen

An automated continuous-monitoring procedure for the determination of acid phosphatase activity in serum.

The method of Hillmann, in which hydrolysis of alpha-naphthyl phosphate by acid phosphatase is coupled to the formation of an alpha-naphthol-Fast Red TR azo-compound, has been adapted for use with the LKB Produkter AB 8600 reaction rate analyzer. Factors which affect the reproducibility of the method are described and its performance is shown to be superior to that of a manual phenyl-phosphate procedure.

Acid Phosphatase

High-pressure liquid chromatographic analysis of aniline and its metabolites.

A high-pressure liquid chromatographic method has been developed for the determination of nanomole quantities of aniline; its metabolites o- and p-aminophenol, phenylhydroxylamine, nitrosobenzene and nitrobenzene; and azobenzene and azoxybenzene which form non-enzymatically by condensation of reactive metabolites. These compounds were separated by reverse-phase chromatography (mu-Bondapak C18 column) and detected spectrophotometrically. The first four components were eluted using methanol-water (15:85) containing 0.26 M ammonium acetate and 0.015 M nickel acetate as mobile phase. The remaining compounds were eluted with methanol-water (50:50). The stabilities of the metabolites were studied electrochemically and results were used in the development of the chromatographic system.

Aniline Compounds

Resonance Raman investigation of an enzyme-inhibitor complex.

The resonance Raman spectrum has been recorded for two different binary complexes formed between 2-carboxy-2'-hydroxy-5'-sulfoformazylbenzene (zincon) and liver alcohol dehydrogenase. The shifts in the zincon spectrum upon complexation with enzyme in one complex are similar to those in model compounds containing azo or formazyl linkages upon complexation of these with zinc. The results are interpreted in terms of complexation of zincon to a zinc atom at the enzyme active site. Since zincon is a coenzyme competitive inhibitor, it is probably bound at or near the coenzyme binding site; the results of this study, therefore, are useful in understanding the chemistry of zinc at the enzyme active site.

Alcohol Oxidoreductases

Production of a mutagen from ponceau 3R by a human intestinal anaerobe.

Ponceau 3R was reduced in vitro by Fusobacterium sp. 2, a human intestinal anaerobe, to a product which is mutagenic when metabolically activated by liver S9 preparations in the Salmonella/mammalian-microsome mutagenicity test. This mutagenic metabolite has been identified as 2,4,5-trimethylaniline.

Aniline Compounds

[Studies of the consecutive hydrolysis of dipeptidyl-4-(phenylazo)-phenylamides by an aminopeptidase from Brassica napus].

The relatively alanine-specific amino peptidase from Brassica napus hydrolyzes dipeptidyl-4-(phenylazo)-phenylamide according to a consecutive mechanism. Enzyme-kinetic studies of dipeptidyl-4-(phenylazo)-phenylamides carried out by means of spectrometrical procedures of measurement are only possible when the increase in the concentration of the fission product p-aminoazobenzene is recorded. For assessing the kinetic parameters of the intermediary steps of the hydrolysis of dipeptidyl-4-(phenylazo)-phenylamides a function is derived describing the dependence of the concentration of fission products of p-aminoazobenzene on reaction time. The satisfactory correspondence of the kinetic parameters calculated for the intermediary-originating substrate L-ala-4-(phenylazo)-phenylamide as substrate demonstrates the applicability of the procedure described in the present paper.

Aminopeptidases

[Several features of the antioxidant action of chemical carcinogens].

Comparative studies of antioxidative effects of phenole inhibitors (vitamine E) amino-and sulfur-containing radioprotectors, and chemical cancerogens on oxidation of unsatured fatty acid were carried out. Some polycyclic hydrocarbons and azo-compounds produce a prolonged and stable decrease of peroxide accumulation rate in oxidized oleic acid. Due to this property in the in vivo systems chemical cancerogenes can induce prolonged stable changes in the parameters of vitally important redox processes.

9,10-Dimethyl-1,2-benzanthracene