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Hemolytic drugs aniline and dapsone induce iron release in erythrocytes and increase the free iron pool in spleen and liver.

Incubation of rat erythrocytes with the hydroxylated metabolites of aniline and dapsone (4-4'-diaminodiphenylsulfone), phenylhydroxylamine and dapsone hydroxylamine, respectively, induced marked release of iron and methemoglobin formation. On the contrary, no release of iron nor methemoglobin formation was seen when the erythrocytes were incubated with the parent compounds (aniline and dapsone). The acute intoxication of rats with aniline or dapsone induced a marked increase in the erythrocyte content of free iron and methemoglobin, indicating that the xenobiotics are effective only after biotransformation to toxic metabolites in vivo. Prolonged administration of aniline or dapsone to rats produced continuous release of iron from erythrocytes. Marked iron overload was seen in the spleen and in the liver Kupffer cells, as detected histochemically. The spleen weight in these subchronically treated animals was significantly increased. The free iron pool was markedly increased in the spleen and to a lower extent in the liver. The possible relationships between iron release in erythrocytes, oxidative damage seen in senescent cells, hemolysis, overwhelmed capacity of spleen and liver to keep iron in storage forms and subsequent increase in low molecular weight, catalitically active iron is discussed.

Aniline Compounds↗

Repeatability and reproducibility of high-concentration data in reversed-phase liquid chromatography. III. Isotherm reproducibility on Kromasil C18.

Single component equilibrium isotherms of six compounds (aniline, caffeine, ethylbenzene, phenol, propranolol, and theophylline) were determined by the inverse method on 10 Kromasil-C18 columns, using water-methanol solutions as the mobile phase. This method offers an economic and fast isotherm determination by means of the overloaded band profiles of the compounds. Five out of the ten columns used in this test come from the same batch whilst the other five columns represent five additional batches. Statistical evaluation was used to assess the reproducibility of the isotherm parameters. We found that the column-to-column reproducibility of the isotherm parameters is of the same magnitude as the batch-to-batch reproducibility (with the exception of one outlier column). In most of the cases, the reproducibilities of the saturation capacities and that of the retention factors are excellent, they are typically between 1.2 and 3%, and very often below 2%. Within the limits of the experimental precision, these results agree with those obtained earlier, using a conventional method of isotherm determination.

Adsorption↗

Thin layer chromatography of p-aminophenol in urine after mixed exposure to aniline and toluene.

A simple method of evaluating p-aminophenol in the urine of people exposed simultaneously to aniline and toluene relies on separating p-aminophenol from hippuric acid and other physiological components of the urine by thin layer chromatography. The adsorbents and developing system have been thus fixed to make possible the separation of p-aminophenol from hippuric acid, urea, and creatinine and their quantitative determination. This method also makes possible the determination of p-aminophenol in urine in the presence of hippuric acid. Hippuric acid is a physiological component of urine and also the metabolite of toluene, so the determination of p-aminophenol is possible also after simultaneous exposure to both compounds: aniline and toluene. At the same time the concentrations of urea and creatinine as additional factors may be determined. The limit of detection of the method is: 5 micrograms/ml for p-aminophenol, 9 micrograms/ml for hippuric acid, 8 micrograms/ml for urea, and 6 micrograms/ml for creatinine.

Aminophenols↗

QSARs for monosubstituted anilines eliciting the polar narcosis mechanism of action.

The relative toxicities (log IGC50(-1] of a fairly heterogeneous series of 66 anilines that were monosubstituted in the 2-, 3-, and 4-positions have been evaluated in the 48 h static Tetrahymena population growth impairment system. Quantitative structure-activity relationships (QSARs) were examined using the 1-octanol/water partition coefficient (log KOW) and the summation of the Hammett sigma electronic substituent constant (sigma sigma) as orthogonal independent predictors. Four chemicals, 4-decylaniline, 4-dodecylaniline, 4-tritylaniline and 4-aminophenethyl alcohol, did not elicit the measured response at saturation. Five chemicals, 2-aminophenol, 2-phenylenediamine, 4-aminophenol, 4-phenylenediamine and 4-nitroaniline, had an altered HPLC spectrum with time. As previously reported, the parent compound, aniline, as well as the 4-position halogen derivatives have been shown to be aberrantly more toxic than expected. None of these chemicals were included in QSAR development which employed linear regression analysis. Log IGC50(-1) = 0.599(log KOW) - 0.905 (n = 52, r2 = 0.885, s = 0.265, f = 383.65, Pr greater than f = 0.0001) was found to be a good predictor of relative toxicity of these monosubstituted anilines. The addition of sigma sigma as a second predictor did not improve the predictability of this QSAR. Abiotic loss over the duration of the assay varied markedly with derivative; however, chemical persistence was not considered to be a factor with this model. The above equation was strikingly similar to log IGC50(-1) = 0.595(log KOW) - 0.996 (n = 67, r2 = 0.866, s = 0.254, f = 421.64, Pr greater than f = 0.0001), a previously developed QSAR from data on a heterogeneous set of monosubstituted phenols. The data for these two equations were combined and subsequent regression analysis resulted in log IGC50(-1) = 0.588(log KOW) - 0.939 (n = 119, r2 = 0.873, s = 0.261, f = 806.49, Pr greater than f = 0.0001). The authors feel that this represents the log KOW-dependent QSAR in the Tetrahymena population growth assay for the polar narcosis mechanism of toxic action.

Aniline Compounds↗

Use of an automated on-line SPE-HPLC method to monitor caffeine and selected aniline and phenol compounds in aquatic systems of Macedonia-Thrace, Greece.

Caffeine and selected aniline and phenol compounds have been monitored in the river, lake, and ground water of Northern Greece (Macedonia-Thrace) from September 1999 to December 2000 by means of a fully automated on-line SPE-HPLC method. Among the target aniline and phenol compounds the most abundant was 2,6-di-tert-butyl-4-methylphenol, which was found to be present in both surface and ground water samples. Caffeine was also very frequently present in river and ground water, although its presence in lake water was rare. Caffeine and 2,6-di-tert-butyl-4-methylphenol were also monitored by off-line SPE of water samples and GC-ion-trap MS analysis of extracts.

Aniline Compounds↗

Breakage and binding of DNA by reaction products of hypochlorous acid with aniline, 1-naphthylamine, or 1-naphthol.

Hypochlorous acid (HOCl) is a chemically reactive oxidant and a potent microbicidal agent that is synthesized in phagosomes of inflammatory neutrophils and released into extracellular spaces. Besides reducing pathogenicity by reacting with phagocytized infectious agents, HOCl may damage tissues and yield toxic products upon reaction with various other molecules, including xenobiotics. As model xenobiotics, the substituted aryl compounds aniline, 1-naphthylamine, and 1-naphthol (1-NOH) were investigated herein for their potential to react with HOCl and the transformed into genotoxic products. The compounds were first exposed to HOCl (25-150 microM) in phosphate buffer and afterward used to treat human fibroblasts or purified DNA. DNA single-strand breaks in cells and the binding of HOCl-reacted 1-[14C]NOH to purified DNA were assessed by DNA alkaline elution and scintillation spectrometry, respectively. It was found that neither HOCl nor compounds alone could break cellular DNA. But HOCl-reacted compounds produced up to 400 rad equivalents of DNA breaks. HOCl reaction products of aniline and the model bicyclic aryl compounds differed in their DNA-breaking characteristics. HOCl-reacted 1-[14C]NOH was stable and bound to DNA at up to 124 pmol/mg DNA. Sodium thiosulfate, glutathione, and taurine inhibited the transformation reactions; but only the former two blocked binding of HOCl-reacted 1-NOH to DNA. Ultraviolet spectra showed that HOCl reacted rapidly (less than 1 min) and equally well with 1-NOH at pH 7.2 or at an intraphagosomal pH of 5.0. Reaction concentrations of HOCl in this study were 2- to 11-fold lower than levels generated in vitro by stimulated neutrophils. These results show that certain aryl compounds can react readily with approximated physiological levels of HOCl (-OCl) to form relatively long-lived products that bind DNA and are genotoxic to human cells.

1-Naphthylamine↗

[Biosensors for detecting organic compounds. II. Sensors for carbohydrates, aromatic, heterocyclic and other organic compounds].

The use of biosensors for detecting aromatic compounds (aniline, hydroquinone, phenol, and N,N-dimethyl-p-phenylenediamine), heterocyclic compounds (adenosine, AMP, ATP, bilirubin, hypoxanthine, guanine, inosine, inosine 5'-phosphate, xanthine, creatinine, uric acid, and NAD), carbohydrates (glucose, galactose, lactose, maltose, and sucrose), vitamins, antibiotics, steroids, mutagens, and organophosphorous pesticides is discussed. Basic metrological characteristics of these biosensors are reviewed.

Biosensing Techniques↗

Heterocyclic synthesis with nitriles: new routes for synthesis of pyridazines, pyridines and their fused derivatives.

Phenylazocyanothioacetamide 1 reacts with malononitrile to afford the pyridinethione 4 which reacts with phenacylbromide to yield the pyridine-S-phenacyl derivative 6. 1 reacts with ethyl cyanoacetate to yield the pyridazine derivative, 8, and with phenacyl bromide to afford the N-phenacyl derivative 11, instead of the thiazole 10. Compound 11 afforded the pyrazolopyridine 13 on reaction with malononitrile while 10 was obtained on coupling of the thiazole 14 with diazotised aniline. Compound 10 reacts with malononitrile to afford the thiazolyl pyridazine 15. Compound 1 reacts with malononitrile dimer to afford the pyridopyridazine derivative 17a. 1 reacts also with active methylene heterocycles to afford the pyrazolo and thiazolo-fused pyridazines 20 and 23 respectively.

Acetamides↗

Effects of nitrosation on the formation of cyanide in publicly owned treatment works secondary effluent.

Cyanide has been detected in the effluents of some publicly owned treatment works (POTWs) at levels exceeding the influent concentration. The presence of nitrite ion (NO2-) as a common constituent in domestic wastewater effluents may play an important role in the formation of cyanide through reaction with certain kinds of organic compounds, especially aromatic compounds. Laboratory studies with seven organic compounds (aniline. p-toluidine, phenol, 1,2,4-trihydroxybenzene, L-serine, glycine, and benzoic acid) revealed that cyanide can be formed by reaction of nitrite with some of these compounds. The most substantial free cyanide (HCN. CN-) production observed at 25 degrees C was 0.15 mg/L from reaction of 0.01 mM 1.2.4-trihydroxybenze with 5 mg/L nitrite for 72 hours. Substantial free cyanide formation was also observed at pH 2-4 in experiments with POTW effluents when reactive organics and nitrite were both added to wastewater. Formation of cyanide through nitrosation was strongly pH dependent, being most significant at low pH (2 to 4) and negligible at neutral-to-high pH. This result points to nitrous acid (HNO2) as being more reactive than the dissociated NO2- ion. The reaction of these nitrite species with organics also occurs in conventional analyses for total cyanide which involve distillation under strongly acidic conditions. Sufficient sample pretreatment with sulfamic acid at the time of sampling, not at the time of analysis. is highly recommended to prevent biasing analytical measurement of total cyanide in POTW effluents.

Cyanides↗

[Retention behavior of solutes on liquid chromatographic column packed with dynamically modified zirconia].

Zirconia was dynamically modified with stearic acid, beta-cyclodextrin and sodium dodecylsulfonate, separately, to form liquid chromatographic packings. The chromatographic behaviors of aromatic hydrocarbons, acidic compounds (phenol, nitrophenols and benzoic acids) and basic compounds (aniline, nitroanilines and toluidines) were investigated on these modified zirconia packings with a mixture of methanol/water as the mobile phase. On stearic acid modified zirconia, aromatic hydrocarbons and the basic compounds exhibit symmetrical peaks. The retention time of these solutes decreases with increasing the concentration of methanol in the mobile phase. When the mobile phases with stearic acid were used, the retention time of these solutes has a maximum with variation of stearic acid concentration (0-1.0 mmol/L) in the mobile phase. However, the acidic compounds such as nitrophenols and benzoic acids are strongly adsorbed and can not be eluted from the column with the mobile phases. No leaking of stearic acid on the modified zirconia was found after 3000 column volumes of the methanol/water mobile phase were used. The results showed that the stearic acid modified zirconia can be used as a stationary phase for reversed-phase liquid chromatography. On beta-cyclodextrin modified zirconia, aromatic hydrocarbons and basic compounds exhibit shorter retention time than those on the stearic acid modified zirconia under the same mobile phase composition, however, nitrophenols can be eluted but give unsymmetrical peaks. On sodium dodecylsulfonate modified zirconia packings, the basic compounds can not be retarded; Aromatic hydrocarbons and acidic compounds exhibit short retention time. The results can be ascribed to the weak adsorption of sodium dodecylsulfonate on the zirconia.

Adsorption↗