Effect of 4,4'-diaminodiphenylmethane against Fasciola hepatica in the rabbit and in cattle.
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Aniline Compounds↗
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Sensitization to methylenedianiline and para-structures.
A toxic-allergic skin reaction of the face, neck and arms due to accidental contact with methylenedianiline (syn: 4-4'-diaminodiphenylmethane) is reported in a cleaner at a chemical plant. Patch tests revealed sensitization to chemicals of the para-group. Earlier exposure to it was unlikely. Previous sensitization to related chemicals and possible cross-sensitization was considered to be the primary cause of the allergy and the clinical manifestations.
Adult↗
Hydroxylation of 4,4'-methylenebis(2-chloroaniline) by canine, guinea pig, and rat liver microsomes.
An in vitro microsomal mixed function oxidase enzyme system was used to study the phase I metabolism of 4,4'-methylenebis(2-chloroaniline) (MBOCA) by dog, guinea pig, and rat liver. TLC with color development and autoradiography, and HPLC with detection by UV absorbance and radioactivity flow monitoring were utilized to isolate metabolites. Reference standards of the N-oxidized metabolites were prepared by oxidation of MBOCA with 3-chloroperoxybenzoic acid and structures confirmed by mass spectrometry and proton NMR. These were utilized to identify the N-hydroxy and nitroso metabolites of MBOCA isolated from the microsomal incubations by comparison of their HPLC retention times and mass spectra. The structure of the o-hydroxy metabolite (ring, ortho to the amine) isolated from the microsomal incubations was elucidated by mass spectrometry and proton NMR. N- and o-hydroxylations of MBOCA were shown to increase with incubation time, microsomal protein, substrate, and NADPH concentration, and were inhibited by 2,3-dichloro-6-phenylphenoxyethylamine, an inhibitor of the microsomal mixed function oxidase enzyme system. Guinea pig liver microsomes oxidized MBOCA to the N-hydroxy metabolite predominantly, whereas the dog liver formed predominantly the o-hydroxylated metabolite, with significant amounts of the hydroxylamine as well. The rat liver formed lesser amounts of the N- and o-hydroxylated metabolites, but larger numbers of other polar compounds.
Animals↗
Bisphenol A accumulation in the freshwater clam Pisidium amnicum at low temperatures.
Toxicokinetics of (14)C-labeled bisphenol A (BPA) was studied in the small freshwater clam Pisidium amnicum at four ecologically relevant low temperatures (2, 6, 8, and 12 degrees C). The uptake clearance (k(u)) of BPA increased from 1.49 to 6.55 ml x g(-1) x h(-1) as temperature increased from 2 to 8 degrees C but decreased slightly again at the highest temperature. The depuration of BPA was very slow and statistically insignificant at 2 degrees C, but the depuration rate ( k(d)) increased linearly as temperature increased from 2 to 12 degrees C. The longest half-life of BPA in clam tissues, 221 h, was found at the lowest temperature, and the highest bioconcentration factor of 144 was measured at 8 degrees C. Data show that P. amnicum accumulates BPA so that the bioconcentration factor rises over 100 at each temperature tested. Further, the data demonstrate the importance of temperature on the processes that control both the uptake and elimination of this compound.
Animals↗
Integrated modelling of two xenobiotic organic compounds.
This paper presents a dynamic mathematical model that describes the fate and transport of two selected xenobiotic organic compounds (XOCs) in a simplified representation of an integrated urban wastewater system. A simulation study, where the xenobiotics bisphenol A and pyrene are used as reference compounds, is carried out. Sorption and specific biological degradation processes are integrated with standardised water process models to model the fate of both compounds. Simulated mass flows of the two compounds during one dry weather day and one wet weather day are compared for realistic influent flow rate and concentration profiles. The wet weather day induces resuspension of stored sediments, which increases the pollutant load on the downstream system. The potential of the model to elucidate important phenomena related to origin and fate of the model compounds is demonstrated.
Benzhydryl Compounds↗
Photonic and electrochemical properties of adsorbed [Ru(dpp)2(Qbpy)]2+ luminophores.
Dense monolayers of [Ru(dpp)2Qbpy]2+, where dpp is 4,4'-diphenylphenanthroline and Qbpy is 2,2':4,4' ':4'4' '-quarterpyridyl, have been formed by spontaneous adsorption onto clean platinum microelectrodes. The cyclic voltammetry of these monolayers is nearly ideal, and three redox states are accessible over the potential range of +/-1.3 V. Chronoamperometry conducted on the microsecond time scale has been used to probe the dynamics of heterogeneous electron transfer and indicates that the standard heterogeneous electron-transfer rate constant, k degrees , is approximately 106 s-1. The metal complex emits at approximately 600 nm in fluid and solid solution as well as when bound to a platinum electrode surface within a dense monolayer. In the case of the monolayers, it appears that the excited states are not completely deactivated by radiationless energy transfer to the metal because electronic coupling between the adsorbates and the electrode is weak. The dynamics of lateral electron transfer between the electronically excited Ru2+* and ground-state Ru3+ species has been explored by measuring the luminescence intensity after defined quantities of Ru3+ have been produced electrochemically within the monolayer. The rate of lateral electron transfer is between 8 x 106 and 3 x 108 M-1 s-1, indicating efficient electron transfer between adsorbates in close-packed assemblies. Voltammetry conducted at megavolt per second scan rates has been used to directly probe the redox properties of the electronically excited species.
Adsorption↗
Exposure to 4,4'-methylenediphenyl diisocyanate (MDI) during moulding of rigid polyurethane foam: determination of airborne MDI and urinary 4,4'-methylenedianiline (MDA).
Occupational exposure to 4,4'-methylenediphenyl diisocyanate (MDI) was measured during moulding of rigid polyurethane foam. The aim of the study was to find out whether an MDI-derived urinary amine metabolite could be detected in the urine of workers exposed to apparently low levels of MDI. Airborne MDI was sampled on 1-(2-methoxyphenyl)-piperazine (2MP)-impregnated glass fibre filters and determined by high-performance liquid chromatography (HPLC) using ultraviolet (UV) and electrochemical (EC) detection. The limit of detection of MDI was 3 ng ml-1 for a 20 microliters injection. The precision of sample preparation, expressed as relative standard deviation (RSD), was 1.3% with UV detection and 2.1% with EC detection at a concentration of 70 ng MDI ml-1 (n = 6). The 2MP-MDI derivative was stable at +4 degrees C up to eight weeks. The accuracy of the method was validated in an international quality control programme. Workers (n = 57) from three different factories participated in the study. Urinary 4,4'-methylenedianiline (MDA) metabolite was determined after acid hydrolysis as heptafluorobutyric anhydride derivatives by gas chromatography-mass spectrometry using chemical ionisation and monitoring negative ions. The limit of detection in urine was 0.2 nmol l-1. The precision of six analyses for a urine sample spiked to a concentration of 1 nmol l-1 was 29% (RSD). The MDI concentrations were below the limit of detection in most (64%) of the air samples collected in the worker's breathing zone. Still, detectable amounts of MDA were found in 97% of the urine samples. Monitoring of urinary MDA appears to be an appropriate method of assessing MDI exposure in work environments with low or undetectable MDI concentrations in the workplace air.
Adult↗
A new tool for sampling airborne isocyanates.
A new sampling system is presented that uses solid sorbent media contained in a tube for the determination of airborne isocyanates (2.4-2.6 toluene diisocyanate, hexamethylene diisocyanate, and 4.4' diaminodiphenylmethane diisocyanate). The method is compared with the National Institute for Occupational Safety and Health (NIOSH) Method P&CAM 5505 (Revision #1). Experimental tests yielded results that were highly concordant with the NIOSH method.
Air Pollutants↗
4,4'-Methylenedianiline and its dihydrochloride salt.
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Aniline Compounds↗
Combined asthma and alveolitis due to diphenylmethane diisocyanate (MDI) with demonstration of no crossed respiratory reactivity to toluene diisocyanate (TDI).
Two workers, who developed asthmatic symptoms, were studied with inhalation provocation tests using diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI). The subjects showed specific asthmatic reactions to MDI challenge (more than 20% fall in FEV1), and one also had an alveolar response. Alveolitis was suggested by fever, basal crackles, increased neutrophil counts in venous blood and in bronchoalveolar lavage. The asthmatic reaction to MDI challenge was associated with an increase in airway responsiveness to methacholine in both subjects. We conclude that MDI is a cause of asthma and/or hypersensitivity pneumonitis in workers exposed to diphenylmethane diisocyanate.
Adult↗
[Effect of 4, 4'-diaminodiphenylmethane and increased ambient temperature on bromide thaleine elimination in male Wistar rats].
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Aniline Compounds↗
Mutagenicity of bisphenol A (4,4'-isopropylidenediphenol) in vitro: effects of nitrosylation.
Bisphenol A (4,4'-isopropylidenediphenol) is a common component of polycarbonate plastics and epoxy resins. Since bisphenol A-containing plastics and resins have found uses in food-contact items, its potential migration into foodstuffs and possible health consequences have been the focus of many recent studies. However, the potential mutagenic activation of bisphenol A by nitrosylation has received little attention. Incubation of bisphenol A with sodium nitrite under acidic conditions produced a yellow-brown product. When nitrosylated bisphenol A was tested in the Ames Salmonella/microsome assay at 100 ng to 1 mg/plate, dose-dependent increases in mutagenicity were found in both TA98 and TA100 Salmonella strains. These results indicated the presence of a direct-acting mutagenic activity causing both frameshift and base pair mutations, respectively. When compared to colony formation in untreated controls, the addition of rat liver S9 for metabolic activation had little influence on revertant colony formation. Unreacted bisphenol A dissolved in DMSO, acidic buffer, or inactivated nitrosylation solution showed negligible mutagenicity. When the nature of the mutagenic changes was examined using the Ames II trade mark Assay, a variety of base pair changes was found including T:A to A:T - S9, G:C to A:T +/- S9,C:G to A:T +/- S9 and C:G to G:C +/- S9. Bisphenol A also induced frameshift mutations at G:C sites. In addition, the presence of electrophiles was shown by the production of an intensely coloured orange-red product upon incubation of nitrosylated bisphenol A with the nucleophile 4-(4'-nitrobenzyl)pyridine. These findings suggest that migration of bisphenol A into nitrite containing foodstuffs, or its ingestion in the presence of nitrite, could lead to the formation of mutagenic compounds.
Air Pollutants, Occupational↗
Impurities in industrial grade 4,4'-isopropylidene diphenol (bisphenol A): possible implications for estrogenic activity.
Fifteen trace impurities, including a novel cyclohexene derivative, have been identified and quantified in samples of an industrial grade of the oestrogen-active compound 4,4'-isopropylidene diphenol (bisphenol A). All of these compounds, like bisphenol A itself, possess phenolic hydroxyl groups para to other substituents and all thus might also have oestrogenic properties. Published studies on the endocrine disrupting properties of bisphenol A have not considered potentially active impurities but full assessment of the oestrogenicity of bisphenol A, as it is used commercially, will become possible when adequate supplies of these compounds are available through synthesis.
Benzhydryl Compounds↗
Uterotrophic effects of benzophenone derivatives and a p-hydroxybenzoate used in ultraviolet screens.
Ultraviolet (UV) sunscreen products are popular because of concerns about UV radiation and skin cancer. Unfortunately, some of these products contain agents with estrogenic activity. We used an ovariectomized rat uterotrophic assay to measure the estrogenic activities of 2,4-dihydroxybenzophenone (2,4-DHBP), 2,2',4,4'-tetrahydroxybenzophenone (2,2',4,4'-THBP), and 4-hydroxybenzoic acid isobutyl ester (isobutyl-paraben), which are agents in UV sunscreens, and ethynyl estradiol (EE) and bisphenol A (BPA), which are positive controls. All chemicals increased rat uterine weights. The 10% effective doses (ED10, mg/kg/day) of EE, BPA, 2,4-DHBP, 2,2',4,4'-THBP, and isobutyl-paraben, as determined by Hill equation analysis, where 5E-5, 41.1, 544.6, 33.0, and 230.9, respectively, and their relative potencies against EE were about 1/800,000, 1/10,000,000, 1/600,000, and 1/4,000,000, respectively. Our findings indicated that UV screens contain weak estrogenic compounds.
Animals↗
Potent and selective ligands for the dopamine transporter (DAT): structure-activity relationship studies of novel 4-[2-(diphenylmethoxy)ethyl]-1-(3-phenylpropyl)piperidine analogues.
Molecular structural modifications of 4-[2-(diphenylmethoxy)ethyl]-1-(3-phenylpropyl)piperidine (1a), a dopamine transporter (DAT)-specific ligand, generated several novel analogues. Biological activities of these new molecules for their binding to the DAT and serotonin transporter (SERT) were evaluated in rat striatal membranes. Some of these new analogues were more potent and selective than GBR 12909 when their binding to the DAT relative to SERT was compared. Thus compounds 9 and 19a were among the most potent (IC50 = 6.6 and 6.0 nM, respectively) and selective (DAT/SERT = 33.8 and 30.0, respectively) compounds in this series, and they were more active than GBR 12909 (IC50 = 14 nM, DAT/SERT = 6.1). Introduction of a double bond in the N-propyl side chain of these molecules did not influence their activities to a great extent. Bioisosteric replacement of the aromatic phenyl group by a thiophene moiety produced some of the most potent compounds in this series.
Animals↗
[Migration of bisphenol A and benzophenones from paper and paperboard products used in contact with food].
Migration of bisphenol A (BPA) and benzophenones, i.e., benzophenone (BZ), 4-(dimethylamino)benzophenone (DMAB), Michler's ketone (MK) and 4,4'-bis(diethylamino)benzophenone (DEAB), from 21 paper and paperboard products (15 recycled paperboard boxes and 6 virgin paper products) used in contact with food was examined. Migration levels of compounds from recycled paperboard were compared under various food-simulating conditions. BPA showed the highest migration into 20% ethanol and benzophenones into 95% ethanol. No compounds migrated from virgin paper products, but compounds did migrate into food simulants from recycled paperboard food boxes. BPA migrated into 20% ethanol from all recycled paperboard food boxes between 1.0 and 18.7 ng/mL. Into 95% ethanol, migration of BZ was observed in 8 samples (1.0-18.9 ng/mL), DMAB in 12 samples (1.2-3.7 ng/mL), MK in 13 samples (1.9-9.0 ng/mL), and DEAB in 13 samples (1.0-10.6 ng/mL). The highest migration level was 27.2 ng/mL and most of the migration levels were below 10 ng/mL. These values are sufficiently low compared with the TDI and NOAEL levels. Moreover, the amount of food in daily meals that comes into contact with paperboard products is relatively small. Consequently, it was concluded that there was no safety concern regarding the tested compounds in recycled paperboard food boxes.
Benzhydryl Compounds↗
Acetylation pharmacogenetics: profiles of arylamine pharmacology and toxicology in a genetic mouse model.
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Acetylation↗
Analysis of a carcinogen, 4,4'-methylenedianiline, from thermosetting polyurethane during sterilization.
Polyurethane (PU) is widely used in medical devices such as potting material in artificial dialysis devices, plasma separators, etc. Gamma-ray irradiation is frequently used for the sterilization of such devices. This paper reports that a carcinogen, 4,4'-methylenedianiline (MDA, p,p'-diaminodiphenylmethane), is produced from medical thermosetting PU by gamma-ray irradiation. Gamma-ray irradiated PU was immersed in methanol or equine serum. The serum was treated with a mixture of 5N HCIO4:acetonitrile (1:10) in order to deproteinate and recover MDA. It was found that MDA is formed from thermosetting PU at around a few ppm in the original sample. The production of MDA increased with increasing irradiation dose. The MDA amount formed was related to the irradiation dose by a second order equation. Results of methanol and serum extraction were similar. Pressurized steam (autoclave) sterilization in place of gamma-ray sterilization was also examined. MDA production was not found in autoclave sterilization procedures. Gel permeation chromatography (GPC) of methanol or N,N-dimethylformamide (DMF) extract of irradiated PU showed that the PU oligomers eluted. Time course of methanol extract of irradiated PU was detected at 245.5 nm. This showed an exponential decline regardless of doses of irradiation.
Aniline Compounds↗