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At least 19 recordsLinked to original sources
PubMed1980

[Evaluation of occupational benzidine exposure of workers in automated benzidine plants].

The exposure to benzidine under old production conditions, during start-up and at normal work in the new benzidine production division in one of the plants in Poland was compared. In comparison with the old production conditions, in the automatized production process airborne benzidine concentrations were 10-fold lower so that the geometric mean of benzidine concentrations was 0.0008 mg/m3. The approximate annual dose of absorbed benzidine amounted to 0.065 mg, as estimated from urinary benzidine concentrations, and was three times lower than the one found in the old productive conditions, i.e. 0.2 mg. The benzidine absorption in the respiratory system was approx. 10%, the remaining part of the dose was probably absorbed by skin. This was proved by high concentrations of benzidine on the skin (epigastrium-up up to 300 micrograms/dcm2, palm-up to 680 micrograms/dcm2), and objects (up to 400 micrograms/dcm2). The results indicate a need to maintain the hygienic regime, introduced in the old productive conditions, including the establishment of the age up to which workers older than 50 may be employed. The cleanness in all the premises should be improved.

Air Pollutants↗
PubMed1990

Biomonitoring of aromatic amines. III: Hemoglobin binding of benzidine and some benzidine congeners.

Covalent binding of benzidine and some congeners to hemoglobin was studied in female Wistar rats after oral administration. Hemoglobin adducts were hydrolyzed under alkaline conditions, and the arylamines extracted and analysed by HPLC with electrochemical detector. With benzidine, three cleavage products were observed, the major component being monoacetylbenzidine. This indicates that 4-nitroso-4'-N-acetylaminobiphenyl is the major reactive metabolite in erythrocytes. In addition benzidine and 4-aminobiphenyl were identified. The latter indicates a hitherto unknown metabolic pathway of benzidine. With 3,3'-dichlorobenzidine-dihydrochloride, 3,3'-dimethoxybenzidine and 3,3'-dimethylbenzidine two cleavage products were observed, the parent diamines being present in excess to or in amounts comparable to the monoacetyl derivative. With 3,3',5,5'-tetramethylbenzidine a hemoglobin adduct could not be found. When the azo dye direct red 28 was administered to the animals, the three cleavage products typical for benzidine were found, indicating that benzidine became bioavailable after reductive cleavage of the azo compound. In this case the fraction of 4-aminobiphenyl was greater than after benzidine. It is proposed to use the analysis of hemoglobin adducts in human blood to control the exposure of individuals to these carcinogenic chemicals in the course of biochemical effect monitoring.

Administration, Oral↗
PubMed1981

Search for benzidine and its metabolites in urine of workers weighing benzidine-derived dyes.

Urinary benzidine and conjugates have been used to assess the extent of occupational exposure to benzidine-based azo dyes. The aim of the present study was to investigate the presence of benzidine and its conjugates in the urine of workers exposed to benzidine-derived dyes. Urine samples were collected from 29 workers in three textile dyehouses, two tanneries, and two dyestuff quality control laboratories in West Yorkshire and Lancashire. In 200 samples, obtained over a period of 15 months and analysed by gas chromatography/mass spectrometry, no free benzidine or monoacetylbenzidine was detected. Nevertheless, after strong acid hydrolysis of urine samples taken on two separate occasions from textile dye weighers where the standard of hygiene appeared below average, trace amounts of benzidine were detected suggesting the excretion of a benzidine derived dye or a metabolite thereof.

Benzidines↗
PubMed1991

Conjugates of benzidine with a ternary phenol-containing copolymer of N-vinylpyrrolidone as test antigens for the detection of benzidine in human serum.

Water-soluble polymeric amide and azo derivatives of benzidine, based on the terpolymer N-vinylpyrrolidone-crotonic acid-p-crotonoylaminophenol, which possesses adjuvant activity, were synthesized. By means of a double diffusion reaction in agar and a complement-binding reaction it was found that immunization of rabbits with the benzidine-polymer antigens (with or without complete Freund's adjuvant) led to the formation of highly specific antibodies against the hapten benzidine. Sera from rabbits immunized with these conjugates of benzidine may thus be used for the detection of benzidine in the sera of workers exposed to this chemical.

Animals↗
PubMed1981

Occupational exposure to aromatic amines: benzidine and benzidine-based dyes.

Large-scale production of aromatic amines that serve as intermediates in the aniline dye industry began in this country during World War I. In the United States, the first known occupationally induced aromatic amine cancers of the bladder were observed at a dye factory in 1931. Additional cases of benzidine-related bladder cancer was subsequently reported at this same facility and at numerous other dye works in this country and throughout the world. In 1974, the Occupational Safety and Health Administration promulgated a standard to control the production and use of benzidine in the workplace. Although hazards associated with benzidine exposure have been reduced, a carcinogenic risk due to benzidine-based dye exposure is now apparent. In addition, several dyes produced from o-tolidine and o-dianisidine, carcinogenic compounds structurally related to benzidine, have demonstrated metabolism to their respective parent compounds. The history of occupational bladder cancer in the United States is traced and measures taken by the Occupational Safety and Health Administration to reduce exposure to this hazard are described.

Animals↗
PubMed1985

Differential serum protein binding of benzidine- and benzidine-congener based dyes and their derivatives.

Environmental dyes and their derivatives, some of which are genotoxic, must be transported within the body to the tissues which they affect. One mechanism for this can be observed directly by crossed immunoelectrophoresis (X-IEP). Binding of these chemicals to certain serum proteins changes electrophoretic and immunoprecipitation morphology in X-IEP patterns. This is demonstrated here for four azo dyes derived from benzidine, 3,3'-dimethylbenzidine, and 3,3'-dimethoxybenzidine, and their parent aromatic amines. Direct Red 2 (a 3,3'-dimethylbenzidine-based dye), Direct Blue 15 (a 3,3'-dimethoxybenzidine-based dye), Direct Black 38 (a benzidine-based dye), and Evans Blue (a 3,3'-dimethylbenzidine-based dye) all bound to albumin, alpha 1-lipoprotein, beta-lipoprotein, and hemopexin. Direct Red 2 only slightly affected the mobilities of these proteins. Direct Blue 15 bound also to prealbumin and alpha 1-antichymotrypsin, and degraded C3 globulin. Direct Black 38 and Evans Blue bound to numerous additional proteins. Evans Blue bound variably to proteins of sera from different individuals, suggesting that there are individual differences in serum protein binding capabilities for these chemicals. Of the three derivatives of the benzidine dyes, only 3,3'-dimethylbenzidine caused changes in X-IEP patterns, indicating its binding to the serum proteins. This chemical differentially affected sub-populations of alpha 1-lipoprotein, either by altering its electrophoretic mobility or inhibiting its recognition by antibodies. Autoradiographic analyses demonstrated the binding of benzidine and 3,3'-dimethylbenzidine to both alpha 1- and beta-lipoproteins.

Azo Compounds↗
PubMed1986

Internal exposure of rats to benzidine derived from orally administered benzidine-based dyes after intestinal azo reduction.

The role of the rat intestinal flora in the azo reduction of some benzidine-based dyes was studied in vitro and in vivo. The formation of benzidine was measured after anaerobic incubation of direct black 38, direct blue 6 and direct brown 95 in the presence of caecal bacteria in vitro. Benzidine was absorbed from the intestinal tract much better than the parent compounds. Oral administration of direct black 38 or direct brown 95 to Wistar rats results in the urinary excretion of mutagens. After oral administration of these dyes to germ-free Wistar rats no mutagenicity was observed in urine. The present results show that after oral administration, reduction by the intestinal flora should be considered as the first essential step in the biotoxification of benzidine-based dyes.

Administration, Oral↗
PubMed1975

Metabolic reduction of benzidine azo dyes to benzidine in the rhesus monkey.

Rhesus monkeys were fed azo dyes derived from benzidine (a known human bladder carcinogen). The urinary excretion of free benzidine was assayed and compared to the amount excreted when benzidine itself was fed. A substantial amount of the dye fed was converted to free benzidine. Results indicate that the simple precaution in the use of only azo dyes manufactured from noncarcinogenic aromatic amines, e.g., aniline, for all consumer products appears prudent.

Aminobiphenyl Compounds↗
PubMed2001

Using base-specific Salmonella tester strains to characterize the types of mutation induced by benzidine and benzidine congeners after reductive metabolism.

Although benzidine (Bz), 4-aminobiphenyl (ABP), 3,3'-dichlorobenzidine HCl (DCBz), 3,3'-dimethylbenzidine (DMBz), 3,3'-dimethoxybenzidine (DMOBz) and the benzidine congener-based dye trypan blue (TB) produce primarily frameshift mutations in Salmonella typhimurium, the base-substitution strain TA100 also responds to these compounds when S9 is present. Performing DNA sequence analysis, other investigators have shown that ABP induces frameshift, base-pair and complex mutations. Also, it was found that an uninduced hamster liver S9 preparation with glucose-6-phosphate dehydrogenase, FMN, NADH and four times glucose 6-phosphate gave a stronger mutagenic response than the conventional plate incorporation with rat S9 activation mixture for all the compounds tested. Using the base-specific tester strains of S. typhimurium (TA7001-TA7006) with the above reductive metabolic activation system, we surveyed these compounds for the ability to produce specific base-pair substitutions after reductive metabolism. Bz was weakly mutagenic in TA7005 (0.04 revertants/microg). ABP was mutagenic in TA7002 (1.4 revertants/microg), TA7004 (0.6 revertants/microg), TA7005 (2.98 revertants/microg) and TA7006 (0.4 revertants/microg). DCBz was weakly mutagenic in TA7004 (0.01 revertants/microg). It was concluded that benzidine induced some CG->AT transversions in addition to frameshift mutations. ABP induced TA->AT, CG->AT, and CG->GC transversions as well as GC->AT transitions. DCBz induced only GC->AT transitions. Because DMBz, DMOBz and TB were not mutagenic in this base-substitution mutagen detection system, their mutagenic activity was attributed strictly to frameshift mechanisms.

3,3'-Dichlorobenzidine↗
PubMed1982

Metabolism of azo dyes derived from benzidine, 3,3'-dimethyl-benzidine and 3,3'-dimethoxybenzidine to potentially carcinogenic aromatic amines by intestinal bacteria.

The metabolism of a benzidine-based dye, Direct Black 38, a 3,3'-dimethylbenzidine-based dye, Direct Red 2 and a 3,3'-dimethoxybenzidine-based dye, Direct Blue 15 has been studied both in pure cultures of anaerobic bacteria and in bacterial suspensions derived from the intestinal contents of the rat. All of the pure cultures and the rat intestinal bacteria were able to reduce the azo linkages of Direct Black 38, Direct Red 2 and Direct Blue 15 with the subsequent formation of benzidine, 3,3'-dimethylbenzidine and 3,3'-dimethoxybenzidine, respectively. The metabolites of Direct Black 38, Direct Red 2 and Direct Blue 15 were isolated and identified by gas chromatography/mass spectrometry and had similar chromatographic and mass spectral properties with those of authentic standards. Results from this study indicate that in vitro anaerobic incubations of rat intestinal microorganisms were able to reduce and cleave the azo bonds of dyes derived from benzidine, 3,3'-dimethylbenzidine and 3,3'-dimethoxybenzidine to form potentially carcinogenic aromatic amines.

Anaerobiosis↗
PubMed1986

Reactivity of benzidine diimine with DNA to form N-(deoxyguanosin-8-yl)-benzidine.

Benzidine diimine (BZDI), a reactive intermediate in the metabolic peroxidation of the carcinogen benzidine, has been reported to bind covalently to cellular proteins and nucleic acids. We have examined the nature of this interaction with DNA and have identified a major carcinogen-nucleoside adduct. BZDI (20-50 microM) reacted rapidly with DNA in vitro to give relatively high levels of covalently bound products (1-2 adducts/10(3) nucleotides; 30-45% yield). The binding was completely inhibited by addition of glutathione but was unaffected by acidic pH, air, free radical traps, or strong nucleophiles. Upon enzymatic hydrolysis of the BZDI-modified DNA and subsequent h.p.l.c., a major adduct was isolated and characterized by u.v., mass and proton magnetic resonance spectroscopy as N-(deoxyguanosin-8-yl)-benzidine. The identity of this adduct and its formation under various incubation conditions suggest a reaction mechanism that involves a simple deprotonation of the cationic diimine, formation of an electrophilic arylnitrenium ion, and covalent binding to guanine in the DNA.

Animals↗
PubMed1984

Mutagenicity of benzidine and benzidine-congener dyes and selected monoazo dyes in a modified Salmonella assay.

We have evaluated the mutagenic activity of a series of diazo compounds derived from benzidine and its congeners o-tolidine, o-dianisidine and 3,3'-dichlorobenzidine as well as several monoazo compounds. The test system used was a modification of the standard Ames Salmonella assay in which FMN, hamster liver S9 and a preincubation step are used to facilitate azo reduction and detection of the resulting mutagenic aromatic amines. All of the benzidine and o-tolidine dyes tested were clearly mutagenic. The o-dianisidine dyes except for Direct Blue 218 were also mutagenic. Direct Blue 218 is a copper complex of the mutagenic o-dianisidine dye Direct Blue 15. Pigment Yellow 12, which is derived from 3,3'-dichlorobenzidine, could not be detected as mutagenic, presumably because of its lack of solubility in the test reaction mixture. Of the monoazo dyes tested, methyl orange was clearly mutagenic, while C.I. Acid Red 26 and Acid Dye (C.I. 16155; often referred to as Ponceau 3R) had marginal to weak mutagenic activity. Several commercial dye samples had greater mutagenic activity with the modified test protocol than did equimolar quantities of their mutagenic aromatic amine reduction products. Investigation of this phenomenon for Direct Black 38 and trypan blue showed that it was due to the presence of mutagenic impurities in these samples. The modified method used appears to be suitable for testing the mutagenicity of azo dyes, and it may also be useful for monitoring the presence of mutagenic or potentially carcinogenic impurities in otherwise nonmutagenic azo dyes.

3,3'-Dichlorobenzidine↗
PubMed1984

Reduction to benzidine is not necessary for the covalent binding of a benzidine azodye to rat liver DNA.

The DNA binding of 2 benzidine azodyes, Congo Red and Direct Blue 6, was compared in rat liver. Both dyes showed binding consequent upon metabolism to benzidine, and in each case hydrolysis of the liver DNA yielded N-(deoxyguanosin-8-yl)-N'-acetylbenzidine. The majority of Direct Blue 6-derived radioactivity bound to DNA was present as at least one other novel species. Our preliminary work on the major Direct Blue 6 DNA adduct suggests its structure may be disodium 8-amino-2-[4-(N-deoxyguanosin-8-yl)-aminobiphenyl-4'-yl] azo-1-hydroxynaphthalene-3,6-disulphonate. This adduct may form as a result of the susceptibility of the dye to hepatic azoreductase and its apparent existence may explain the observed potent carcinogenicity of dyes such as Direct Blue 6.

Animals↗