Toxicological European research. Recherche europeenne en toxicologie最新文献

In order to estimate the level of human contamination by cadmium, the metal was analysed in liver and kidneys of 268 persons after death. Analysis was performed by using atomic absorption spectrometry after nitroperchloric mineralization. The concentrations thus determined allowed to calculate, by means of some approximations, the total amounts of cadmium in these organs and also in human body. The values obtained are comparatively low, and they show important variations which are partly related to sex and to age. These results are compared to other authors'.

Collective intoxication resulting from the addition of aniline in adulterated vegetal oils which were re-treated in order to make them available for consumption, was clinically characterized by polyneuritis, atypical pneumonia, symptoms of vascularity. After studying the infection and allergic syndrome, the toxicological approach presented a set of experimental clinical arguments in favor of a specific toxicity of anilides of unsaturated fatty acids. The toxicokinetics of oleylaniline shows a half life of several weeks, which explains its evolution. Its mode of action involves peroxide formation, membrane toxic and attractive substances of immunocompetent cells. Peroxide formation could result from an excess of superoxide ions, an inhibition of superoxide-dismutases, an excessive consumption of NADPH or more often of any facilitation of lipid peroxidation by a biologically active peroxidized intermediate.

Three biological criteria were studied on daphnids after 28 days of contamination with three different concentrations of cadmium (5, 10, 15 micrograms/l), such as mortality, dry weight and reproduction rate relative to general metabolic state of the crustacea. The value of Cl50-28 exceed 15 micrograms/l for dry weight and mortality determinations, on the other hand it is only 10 micrograms/l for reproduction rate. The latter appears as the most sensible criteria.

The distribution of a single oral dose of 14C bithionol sulfoxide in mice was determined by whole body autoradiography. The bithionol sulfoxide was found in the whole organism mainly in richly vascularized organs, liver, kidney, lung. It did not pass through the blood-brain barrier and did not accumulate in any particular organ but persisted in the blood. Observations were performed in 18-day pregnant mice in order to investigate an eventual placental transfer. Six hours after the administration, radioactivity was detected in blood and fetal vascularized tissues.

Many problems about public health are raised by the use of antiinfectious agents in veterinary medicine. Particular attention must be given to the contamination of human food of animal origin and to the exposure of workers manufacturing these drugs. A review of the use of these products in veterinary medicine, particularly that of antibiotics will allow to circumscribe the problems due to drugs which might cause allergy.

The effects of chloramphenicol treatment to rats, by intraperitoneal way on three consecutive days were studied on various enzymatic systems of hepatic microsomes, implicated in the detoxication reactions non induced or induced by phenobarbital. Chloramphenicol increases the activity of reductases like NADPH cytochrome c reductase and neotetrazolium reductases. It does not appear to modify the activity of the N-demethylase systems or of the cytochrome P 450 level contrarily to phenobarbital. Chloramphenicol decreases the activity of microsomal nitro reductases, the production of malonaldehyde and conjugated dienes in the microsomes currently considered as a reliable estimate of the extent of the lipoperoxidation process. These results suggest that chloramphenicol could act like an antioxdant derivative.

The use of a pharmacokinetic model characterized by a new theoretical approach of the enzymatic reaction allows to account for ethanol concentration-time curve (after oral administration in man) and to simulate the evolution of free enzyme concentration. The interpretation of the various phases observed during these kinetics (ethanol, free enzyme) and plasma acetate kinetics (performed in the same study) constitutes an original approach to ethanol metabolism.

Occupational and environmental exposure to cadmium leads to a progressive and almost irreversible accumulation of the metal in the body. The epidemiological and experimental studies carried out by the authors allow them to draw the following conclusions: 1) the kidney is usually the critical organ i.e. the organ exhibiting the first signs of adverse effects following long term moderate exposure to cadmium by inhalation or by ingestion. 2) Cadmium interferes not only with the tubular reabsorption process(es) for low molecular weight proteins (e.g. beta 2 . microglobulin, retinol binding protein) but also with the glomerular or tubular mechanism determining the excretion of high molecular weight proteins (e.g. albumin, transferrin). Both types of proteinuria may occur independently. 3) The renal functional disturbances induced by cadmium and compatible not only with a tubular dysfunction but also a glomerular dysfunction. 4) The early detection of renal disturbances induced by cadmium should not rely only on the determination of total proteinuria but necessitates the analysis in urine of at least one low molecular weight protein (beta 2-microglobulin or retinol binding protein) and one high molecular weight protein (albumin). 5) Before the occurrence of renal dysfunction and providing the intensity of exposure to cadmium is moderate, urinary cadmium reflects mainly the body burden whereas blood cadmium reflects mainly the last few months exposure. 6) In adult male workers occupationally exposed to cadmium, the critical concentration of cadmium in the renal cortex is in the order of 200 ppm. The corresponding critical urinary level is approximately 10 micrograms/g creatinine. The critical level of cadmium in the renal cortex is not reached if the exposure is kept at a level where cadmium in blood does no exceed 1 microgram/100 ml. 7) Comparison of literature data on current exposure of the general population to cadmium and the critical exposure level indicates that some groups of the general population absorb daily amounts of cadmium closed to the critical level. 8) The critical biological levels indicated under (6) do not necessarily prevent an exacerbation of the age-related decline in renal function. 9) A preliminary study performed in Belgium suggests that cadmium might play a role in the increased mortality by renal diseases in a population living in an area polluted by cadmium. More detailed studies are necessary to confirm this hypothesis.