Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Azo Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources
PubMed1985

Chloracne and chloracnegens.

Chloracne, an acneform eruption resulting from poisoning by halogenated aromatic compounds, has been a considerable problem over the last 40 years. The condition is always a symptom of systemic poisoning and should be familiar to all practitioners, particularly dermatologists. It is difficult to treat and can last for long periods without known additional exposure to chloracnegens. Some chloracnegens are capable of causing a variety of systemic signs and symptoms and may be oncogenic. Although there are probably fewer than 4,000 persons with chloracne worldwide, those found with the disorder should be evaluated medically on a regular basis and followed, if possible, throughout their lives.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed2005

Growth, occurrence and development of septa in Plasmopara viticola and other members of the Peronosporaceae using light- and epifluorescence-microscopy.

Although Plasmopara viticola causes grape downy mildew in most, if not all, wine producing countries, many basic biological or chemical aspects are still unknown and thus the histopathological changes during development of this oomycete pathogen were studied. The fluorochromes Aniline blue and Uvitex 2B were successfully used in whole leaf stainings to visualise intercellular hyphae and to investigate septal-development in sporangiophores. The occurrence and transfer of cytoplasm in sporangiophores was studied with the aid of Chlorazole Black E and Phloxin-B. Application of Chlorazole Black E was the most reliable method to differentiate between cytoplasm and septa in sporangiophores due to a high contrast between the dark cytoplasm and the pale septa. In P. viticola, septa were found in the stem and branches of the sporangiophores, but not in the intercellular hyphae, which was in contrast to other oomycetes, such as P. tabacina, Pseudoperonospora cubensis and P. humuli, where septa were frequently found in the mycelium. In order to verify chemical composition of septa, sporangiophores were digested using chitinase and beta-1,3-glucanase. After staining with Aniline blue and Uvitex 2B, the intense fluorescence of septa was conserved after the application of chitinase but not after beta-1,3-glucanase, indicating that septa are mainly composed of beta-1,3-glucans. Pretreatments of infected vine leaves with 2-deoxy-D-glucose (2-DOG) at low concentrations (1-5 mM) led to a disorganisation of the sporangiophore structure of P. viticola, whereas the production of septa was unaffected. Application of 2-DOG at higher concentrations resulted in a reduced length of intercellular hyphae (10 mM) or total inhibition (50 mM) of the intercellular mycelium. Thus, 2 DOG or its analogues interferes with morphogenesis in Plasmopara viticola and may have a deleterious effect on the spread of this downy mildew between plants.

Aniline Compounds↗
PubMed2005

Matrix isolation and computational study of the photochemistry of p-azidoaniline.

The photochemistry of p-azidoaniline was studied in argon matrices in the absence and presence of oxygen. With the help of quantum chemical calculations we were able to characterize the triplet p-aminophenylnitrene as well as the cis- and trans-p-aminophenylnitroso oxides. It was found that the latter two isomers can be interconverted by selective irradiation and that they are ultimately converted into p-nitroaniline. Although restricted wavefunctions of the nitroso oxides are unstable, CASSCF calculations turned up no evidence for the claimed diradical character of these compounds. Also we found no evidence for dioxaziridines as intermediates of the conversion of the nitroso oxides to p-nitroaniline.

Aniline Compounds↗
PubMedDate not supplied

Tetrachloroazobenzene in 3,4-dichloroaniline and its herbicidal derivatives: propanil, diuron, linuron, and neburon.

The presence of 3,3', 4,4'-tetrachloroazobenzene (TCAB) was determined by high performance liquid chromatography in 3, 4-dichloroaniline and herbicides made therefrom. The concentrations of TCAB in 3, 4-dichloroanilines and in different herbicides from a variety of manufacturers ranged from 9 to 1400 micrograms/g (ppm). The chloracnegenic potential of these products, as determined by rabbit ear test, suggests that it is in the same range of 2, 3, 7, 8-tetrachlorodibenzodioxin, a known potent chloracnegenic agent.

Acne Vulgaris↗
PubMed2006

Colour removal from model solutions by coagulation--surface charge and floc characterisation aspects.

Chemical coagulation applied for colour removal from dye bearing solutions has been investigated from the point of view of surface charge progression. Two commercially used dyes, i.e. CI Acid Blue 113 and CI Disperse Blue 26 have been tested, employing three common coagulants: alum, aluminium chloride and ferric chloride. Coagulant type and dose level and pH of the dye solution have been studied as process parameters affecting surface charge and degree of colour removal after filtration of coagulated dye. It has been found, that both dyes could be almost completely removed with the tested coagulants, when supplied however at different dosages. From one side, the correlation between surface charge and colour removal suggests that destabilization of colour colloids occurs as a result of charge neutralization followed by removal by filtration. From other side, the lack of re-stabilization and continued high colour removal even at increased coagulant dosages implies enmeshment of destabilized dye colloids into the hydroxy flocs/precipitates of metal coagulant by "sweep coagulation". Finally, flocs from selected sludge samples have been examined for particle size and shape by image analysis and their key characteristics summarised.

Alum Compounds↗
PubMed1990

Effects of azobenzene and aniline in the rodent bone marrow micronucleus test.

Azobenzene (AZB) is non-carcinogenic in mice, but a potent rat carcinogen, inducing tumours in the spleen and other abdominal organs. The present paper shows that AZB clearly induces micronuclei in the bone marrow of rats at a dose of 375 mg/kg and above. In mice, however, only a marginally positive response was seen at much higher doses, thus reflecting the species-specific carcinogenic effect of the compound. The clastogenic effect of a single dose of AZB was not detectable in the rat 24 h after dosing, but at the 48 h sampling time and later. However, when a multiple-dosing regimen was used, an accumulation of micronucleated polychromatic erythrocytes (PEs) was seen and the effect was detected 24 h after the last dose. Micronucleus induction in rats was paralleled by increased methaemoglobin levels followed by anaemia. This resulted in accelerated erythropoiesis, as indicated by both the increased percentage of PEs in bone marrow and the increased reticulocyte count in peripheral blood. In mice, anaemia and methaemoglobaemia were seen. However, there was no compensatory increase in the percentage of PEs or any consistent change in the reticulocyte count. Stimulation of erythropoiesis could therefore be a contributory factor in the micronucleus induction by AZB seen in rats. One of the major metabolites of AZB, aniline, was also found to cause micronucleus induction in rats. Aniline is also a rat-specific carcinogen. It may therefore be speculated that AZB acts as a carcinogen via the formation of aniline, which might then be metabolized in different ways in rats and mice.

Aniline Compounds↗
PubMed1991

The differential clastogenicity of Solvent Yellow 14 and FD & C Yellow No. 6 in vivo in the rodent micronucleus test (observations on species and tissue specificity).

Solvent Yellow 14 is carcinogenic in rats, inducing neoplastic nodules of the liver, but is non-carcinogenic in mice. The present paper shows that Solvent Yellow 14 induces micronuclei in the bone marrow of rats after a single oral dose of 250 mg/kg and above. In mice, however, there was no increased incidence of micronuclei after single oral doses of up to 2000 mg/kg Solvent Yellow 14, thus reflecting the species specific carcinogenic effect of the compound. The structurally related azo dye FD & C Yellow No. 6 is noncarcinogenic to rats and mice and gave a negative result in both rat and mouse bone marrow micronucleus tests after a single oral dose of up to 2000 mg/kg. The rat bone marrow micronucleus test is therefore capable of discrimination between the carcinogenic and the non-carcinogenic azo dye. A negative result was obtained for Solvent Yellow 14 in an in vivo liver unscheduled DNA synthesis assay after oral doses up to 1000 mg/kg. This result demonstrates the inability of the two in vivo assays used to predict target organ specificity seen in the cancer bioassay.

Animals↗
PubMed1982

The release of 4,4'-diaminobiphenyls from azodyes in the rat.

Six azodyes derived from benzidine, o-tolidine or o-dianisidine were separately administered orally by gavage to rats. Urine was collected over a 24 h period. Following dichloromethane extraction, urines were analysed by h.p.l.c. for the presence of the respective parent amine and its N-acetylated and N,N'-diacetylated derivatives. After alkaline hydrolysis, urines were analysed for the amines resulting from the cleavage of N-conjugates. All six dyes, direct black 38, direct brown 95, direct blue 6, Congo red, trypan blue and Chicago sky blue were found to be reduced, N-acetylated and N-conjugated. However, no N,N'-diacetylated metabolites were detected. After administration of the same dyes via injection into the hepatic portal vein, bile was collected over a 3 h period by cannulation of the bile duct. Urine was withdrawn from the bladder by syringe at the end of the three hours. Both body fluids were analysed for reduction products which were found only in the case of direct black 38, direct brown 95 and direct blue 6. Of the six dyes examined only the three direct dyes were mutagenic to S. typhimurium strains TA98 and TA1538 in the absence of flavin mononucleotide. The same three dyes were also substrates for rat liver microsomal azoreductase enzymes whereas Congo red, trypan blue and Chicago sky blue were shown to be inactive in a previous publication. The possible relationship between these results and the potent carcinogenicity exhibited by direct black 38, direct blue 6 and direct brown 95 is discussed.

Aminobiphenyl Compounds↗
PubMed1988

UDS activity in the rat liver of the human carcinogens benzidine and 4-aminobiphenyl, and the rodent carcinogens 3,3'-dichlorobenzidine and direct black 38.

The activity of benzidine and three structurally related carcinogens in an in vivo/in vitro rat liver assay for unscheduled DNA synthesis is described. The first three of these chemicals, benzidine, 4-aminobiphenyl (4AB) and Direct Black 38 have been reported as positive in this assay by other investigators, albeit the data reported for 4AB were limited. The fourth compound, 3,3'-dichlorobenzidine has not been studied in this assay before. Each compound gave a clear positive response under conditions of routine testing.

3,3'-Dichlorobenzidine↗
PubMed1993

A new trichrome-blue stain for detection of microsporidial species in urine, stool, and nasopharyngeal specimens.

Detection of microsporidia in clinical specimens has relied on electron microscopy, histology, or staining. This article describes further alterations to the modified trichrome staining method which make it easier to identify microsporidial spores. The changes are a decrease in the phosphotungstic acid level and the substitution of a colorfast counterstain, aniline blue, for the fast green of the original stain. The modified stain provides good contrast between microsporidial spores and background material including human and fungal cells. Stool specimens from 139 human immunodeficiency virus-seropositive patients revealed that 5 patients were infected with Enterocytozoon bieneusi and 6 patients had larger spores. Thin-section electron microscopy of the larger spores showed a structure consistent with that of either Encephalitozoon or Septata species. Three of the patients with Encephalitozoon- or Septata-like species had disseminated infection, with spores detected in nasopharyngeal aspirates and urine samples.

AIDS-Related Opportunistic Infections↗