Cross-sensitizations between azo dyes and para-amino compound. A study of 236 azo-dye-sensitive subjects.

Combined sensitizations to different azo dyes, probably based both on true cross-sensitization and on simultaneous positive reactions, have frequently been described. However, since azo dyes are included in the standard series in a minority of countries, the case studies considered comprise, with few exceptions, a small number of subjects. The aim of our study was to investigate cross-reactions between different azo dyes and para-amino compounds in azo-dye-sensitive subjects, to study the clinical aspects of azo dye dermatitis, to assess the relevance of sensitization to azo dyes, and to relate the pattern of cross-sensitizations to the chemical structure of the different dyes. Out of 6203 consecutively tested patients, 236 were sensitized to at least 1 of 6 azo compounds employed as textile dyes, included in our standard series. 107 subjects reacted to Disperse Orange 3 (DO3), 104 to Disperse Blue 124 (DB124), 76 to p-aminoazobenzene (PAB), 67 to Disperse Red 1 (DR1), 42 to Disperse Yellow 3 (DY3), and 31 to p-dimethylaminoazobenzene (PDAAB). Co-sensitizations to para-phenylenediamine were present in most subjects sensitized to DO3 (66%) and PAAB (75%), in 27% and 36% of DR1 and DY3-sensitive subjects, and only in 16% of subjects sensitized to DB124. Apart from the hands and the face, the neck and the axillae were the most frequently involved skin sites. Whereas the involvement of flexural areas was mainly connected with sensitization to DB124, in patients with hand dermatitis and in those working as hairdressers, sensitization to DO3 and PAAB was more frequent. Moreover, in the former patient group, a history of textile dye allergy was most frequently obtained. Out of 33 patients tested with an additional textile dye series, only 5 subjects reacted to anthraquinone dyes. Cross-sensitizations between azo dyes and para-amino compounds can partially be explained on the basis of structural affinities.

MRC-5 línea celular diploide como un modelo para el estudio fármacos con potencialidad carcinogénica / MRC-5 a diploid cellular line as a model for studying potencially carcinogenic drugs

Se evalúa el daño inducido al DNA de células humanas diploides MRC-5 por los siguientes carcinógenos: Benzo (a) pireno (Bp), 9-10 Dimetil, 1, 2, benzantraceno (Bz), 3 Metilcolantreno (Mc) metronidazol (met). El Bp, Bz y Mc produjeron modificaciones en el crecimiento celular, cambios en los cromosomas y cambios morfológicos que se han relacionado con la producción de neoplasias. ElMet no produce cambios en el patrón de crecimiento asociado a neoplasia, comportandose con un inhibidor del crecimiento celular. Creemos que para considerar a un agente químico como potencialmente carcinógeno, debe modificar en patrón de crecimiento con cambios en los cromosomas y modificaciones morfológicas. Este método de cultivo de tejidos tiene importancia como un sistema de cernimiento farmacológico permitiendo el estudio de un gran número de fármacos a un costo relativamente bajo

Mutagenicity to Salmonella of four derivatives of the azo mutagen 5I: some implications for structure--activity databases and the evaluation of combinations of mutagens.

A structure--activity study is described in which four new derivatives of the potent bacterial mutagen 5-dimethylaminophenylazoindazole (5I) have been evaluated for mutagenicity to Salmonella. As expected, monodemethylation of the -NMe2 group of 5I increased its mutagenic potency while replacement of the -NMe2 with a cyclic amine reduced it. However, replacement of the aromatic indazole -NH group (of 5I) by an -NMe group (yielding NMe5I) dramatically attenuated mutagenic potency, a reduction which was both unexpected and not reversed in the monomethyl analogue (NMeMA5I). In competition experiments NMe5I had an inhibitory effect on the mutagenic potency of 5I itself and on that of the nonazo mutagen 2-acetylaminofluorene 2AAF. The results illustrate some of the problems associated with evaluating mixtures for mutagenicity and of assuming simple structure--activity relationships in the absence of relevant experimental data.

Computer-automated prediction of the mutagenicity of benzidine, 4,4"-diaminoterphenyl, 4-dimethylaminoazobenzene and 4-cyanodimethylaniline: comparison with the results of the Second UKEMS Collaborative Study.

There was agreement between the experimental results, obtained in the course of the Second UKEMS Collaborative Study, for the mutagenicity in Salmonella typhimurium of benzidine, 4,4"-diaminoterphenyl, 4-dimethylaminoazobenzene and 4-cyanodimethylaniline and the mutagenicity predicted by CASE (Computer Automated Structure Evaluation), a recently developed artificial intelligence system.

[DNA damage after treatment in-vivo with several aromatic amines: 2,4-diaminotoluene, 4-aminobenzene (aniline) and paradimethylaminoazobenzene (butter yellow)]. / Danno al DNA, dopo tratamento "in vivo" con alcune ammine aromatiche: 2-4 diamminotoluene, 4 amminobenzene (anilina) e paradimetilamminoazobenzene (giallo burro).

Three aromatic amines, 2,4 diaminotoluene, aminobenzene and paradimethylaminoazobenzene were examined for their capability of damaging rat liver DNA. Compounds were tested by the "in vivo"/DNA alcaline elution assay. 2,4 diaminotoluene was very positive, aminobenzene weakly positive, paradimethylaminoazobenzene probably negative. All the compounds were tested at doses already clearly toxic.