European journal of toxicology and environmental hygiene. Journal europeen de toxicologie最新文献

The authors report the results of a series of investigations on the toxic effects produced in mice and rabbits by inhalation of Dimethyl-ether. Median lethal concentration (LC50) and Median lethal time (LT50) were determined in the mouse. Also the effects of DME inhalation on some physiological parameters (blood pressure, heart rate, blood gas and pH data) were evaluated in the rabbit.

Activities, on the hepatic microsomal fraction, of the following enzymes: aniline aromatic hydroxylase, p-nitroanisole O-demethylase, aminopyrine N-demethylase, N-methylaniline N-demethylases, as well as the P-450 cytochrome level, have been evaluated on female rats. During a period of 26 days, they are fed on 4 diets including either: 20% or 30% proteins, or: 1% or 30% lipids. A parallel study is carried out: animals fed on the same diets are given, orally on the 22nd day and for 4 days, a bactericide, the dimethyl-2.3 quinoxaline; the dose is 500 mg/kg/day, with an interval of 24 hours. 1) A stimulation of the microsomal monooxygenase activity and an increase in the P-450 cytochrome level are induced by the dimethyl-2.3 quinoxaline on all animals regardless the diet they are on. 2) The hyperlipidic diet is the only one to induce an increased activity of the same enzymes, but the P-450 cytochrome level remains unchanged. 3) In rats fed on the hyperlipidic diet and treated with dimethyl-2.3 quinoxaline, the effects of this substance and of this diet, on the drug-metabolizing enzymes, become additive.

The authors relate a suicidal poisoning by nitrites. Post mortem findings are reported as well as a method for the quantitative assessment of NO2- in blood, urine, gastric and intestinal contents, kidney and liver. The concentration values obtained are correlated with the methemoglobin figures which indeed are lethal. The highest concentrations of NO2- are found in the small intestine where the nitrites seem to resist chemical decomposition owing to the reducing properties of the bacterial flora.

The toxicant action on hepatocytes of "paraquat" introduced at very low concentrations in an in vitro culture of such cells is here established. Mitoses are slowed down and moreover, the lysosomial system is impaired, thus inducing a decrease in its enzymic reactions and the proliferation of very large vesicles.

Here is an attempt to establish that a close relation exists between the chemical formulae of organophosphates and their affinities for lipids, proteins and water. We carried out this study on two systems similar to human plasma. First, each component was sorted, then the organophosphates were detected and titrated by gas chromatography with flame photometry detector. Thiophosphates had a greater affinity for lipids than phosphates. Fixation of proteins was only observed on three hydrophilous organophosphates: phosphamidon, dichlorvos, ciodrin.

The hydroxyimino-1 methyl-4 pentanone-2 was selected among several oximes because of its highly successful restoring action on dog plasmatic cholinesterases inhibited by DFP (diisopropyl fluorophosphate). During the in vitro study, this storing action was tested on 10 organophosphates. Results are compared to those obtained when contrathion is used.

It is possible through investigation under the electronic microscope to determine the location and nature of lesions with accuracy. These lesions are mainly found on the epithelium of proximal and distal convoluted tubules. However, the extent of lesions together with the deterioration process of the cell-constituents vary from one structure to the other and even from cell to cell. On the other hand, while blood capillary vessels pertaining to tubules may also show moderate lesions, glomerular and interstitial deterioration is rare. Kidney deterioration which may either result directly from one of the poison effects or from related phenomena, is under discussion.

Electrophoresis of mercurial serumalbumin allows isolation of 5 proteic sub-fractions, whose respective importance is appraised by densitometry. In a parallel direction mercury dosages are performed on each sub-fraction. They disclose that there is a relation between mercury fixation and the sub-fractions migration speeds: the 2 sub-fractions with the lowest migration speeds had fixated more mercury than the others.

The oral LD50's for five organothiophosphate pesticides have been determined in CD-1 strain male and female mice. The values in mg/kg are: parathion, 15.0 and 14.3; methyl parathion, 14.5 and 19.5; guthion, 7.15 and 6.35; imidan, 25.2 and 23.1; sumithion, 1,045 and 1,220 respectively. Toxicity was greater parathion but there was no difference in the males. The relationship between chemical structure and toxicity has been discussed. The addition of a methyl group in the meta position of the nitrophenyl group (sumithion) decreased toxicity 72 times compared to methyl parathion. The predicted LD1 and extrapolated LD0.1's have been determined for the five organothiophosphates and the conditions required for accurate results have been established. It has been shown that the slopes of the curves (males vs. females) obtained with 50, 100 and 660 animals are parallel for all compounds health implications of exposure to low levels of environmental pesticides have been discussed.