Toxicological European research. Recherche europeenne en toxicologie最新文献

The toxicity of the weed-killer paraquat is related to the formation of superoxyde radicals responsible of a progressive and usually lethal pulmonary fibrosis. Recognition of lipid peroxidation of membrane bilayers by free radicals as the causative factor pointed to oxygen as an important cofactor in the severity of paraquat poisoning. It has been shown that any FiO2 over 21% accelerates this process and increases the the mortality of rats and humans. FiO2 21% gave a significant reduction of mortality in rats (DOUZE 1976). We proposed this therapy (1978-1879) in 6 cases of paraquat poisoning. It was conducted with induction of a barbiturate coma, hypothermia, curarisation and hypo-oxygenation (FiO2 around 14% thanks to the adjunction of nitrogen to assisted ventilation). In 5/6 patients, these technics did not prevent the evolution towards death. This evolution was in fact predicted, according the following prognostic factors: suicide, more than a mouthful ingestion, oesophago-gastric burns detected by endoscopy, organic renal failure, high plasma paraquat level. Associated methods of elimination (Fuller's earth, provoked diarrhea, furosemide, hemoperfusion and hemodialysis) did not change the early established prognosis. The only survival was observed in an accidental poisoning with undetectable plasma paraquat and isolated oral burns: the herbicide had been probably spit out. This survival cannot be related to hypo-oxygenation. This failure is not definitive, according to us: this therapy should be undertaken only after minimal, accidental poisoning possibly evolving to pulmonary fibrosis. It appears unuseful in massive, suicidal poisonings, leading readily to a lethal circulatory failure.

Respiratory diseases are the most heavy complications that we can meat in self-poisoning persons. Authors report 15 cases of respiratory complications appeared in 824 self-poisoning cases by drugs. Different factors involved in respiratory diseases origin are analysed but only one appears to be significant: the time between poisoning and admission in intensive care unit. The encountered complications are: acute respiratory distress syndrome, Mendelson syndrome, heavy pulmonary infections, pulmonary embolism. Authors argue about the means of prevention. This seems the fundamental aspect, alone capable to decrease the incidence of very heavy complications responsible of a height mortality range (33%).

Method of artificial respirators desinfection by Formaldehyde is studied. Formaldehyde and ammoniac quantitative analysis are performed. Air samples are taken by dry process and by wet process. Two concentrations are in ceiling values for exposure of workers and exceed irritant concentrations during chronic exposition. Particular attention should be paid to perform measurement: air samples must be taken by wet process as artificial ventilation circumstances: indeed in this case air is humidified; potential toxicity is unappreciated in this use. Complementary studies are required.

The Onchocerciasis Control Programme (OCP) is realized in the major part of the treated area by weekly applications of temephos in biotopes of simulles larvae. This insecticide is very effective and its impact on the aquatic fauna is evaluated by means of periodic samplings of the fauna. Therefore, the most sensitive way of tracking down fish poisoning is by studying the brain acetylcholinesterase depression. Evaluated on Tilapia guineensis this lowering is moderate when operational doses are used by OCP. The discovery of resistence to temephos incited researchers of OCP to try remplacement insecticides. Among these, chlorphoxim, chlorpyrifos-methyl and pirimiphos-methyl proved to be the most effect of these three organophosphorus compounds to that of temephos on the acetylcholinesterasic activity of the brain of Tilapia but using a much higher dosage (0,05 mg/l during 24 hrs that is 144 times more than for temephos). The results demonstrate that the three remplacement insecticides have on inhibitive effect plainly more important than that of temephos and that the retour to normal activity requires a much longer time.

Two young people, a 23 year man and his wife aged 21, are admitted in hospital because they complain of headache; nausea, dyspnea. These symptoms are related with the use of a water-reppellent spray in bad conditions; troubles appear because the product is used in an insufficiently ventilated room. At the admission time, the man suffers from coughing, polypnea, giddiness, the fever is 38 degrees, 3 C. The blood gas values are normal. The thoracic Xray is also normal. The woman is more affected the fever is 38,8 degrees C. The signs are worse and the blood value of Co is 5%. The blood gas values are: PO2 64,8 mm HG, SaO2 92,4%, PCO2 28,8 mm Hg. The chest Xray shows signs of acute pulmonary oedema. Corticoïds and furosemide give a progressive improvement. 48 h later a favorable evolution is noted in the two cases. The german manufacturer of the product gave its composition which is as follows: - petrol 17,3% - essence 15,3% - methylen chloride 13,7% - freon (trichlorofluoro-methane - dichlorofluoromethane) 42,2% - impregnant (melamine resin; organic methylic soap) 2,6% - propan butan 9,2%. The compound responsible for the symptomatology is petrol vapour which, if inhalated, is well known to produce pulmonary toxicity. The woman's condition was worse because she used the spray herself and therefore inhaled a lot a vapours. With this type of product the direction for use have to be strictly followed ie the operation must take place in a well ventilated room.

Radioactive arsenic trioxide is given to pregnant mice in order to complete a recent pharmacokinetics study in the same species and to investigate an eventual transplacental passage, whole body autoradiographic study is performed in the mouse after a single administration of that compound considering its fast elimination process. Both in mice and foetus a fixation has particularly kept our attention: the radioactivity is well fixed in the bone marrow and it might be related to some malformations which occur in the newborns.

The authors carried out this study according to three parameters (dose, level, age of the rats and way of administration) on the action of fluor study in liver metabolism of dimethylnitrosamine and benzo(a)pyrene. The results showed that, in parallel with the increase of the dose level, at certain concentrations, it occurs generally an induction of dimethylnitrosamine-demethylase and a decrease in the amount of cytochrome P450 either by intraperitoneal injection, by ingestion or by inhalation. On the other hand, fluoride does not affect benzo(a)pyrene metabolism. Moreover, inhalation of FH looks the most suitable for this study. It allows to keep a relatively constant rate of F' in the blood and bring about more important changes in the metabolism of dimethylnitrosamine (30 to 70% induction) and in the amount of cytochrome P450 (10 to 40% decrease), as compared to the controls. The results suggest that, in the conditions of our experiments, fluoride would exert an favourable effect on the carcinogenic power of dimethylnitrosamine without affecting benzo(a)pyrene one.

The authors report two cases of heroin induced pulmonary edema. In both cases the severity of respiratory failure, attested by a deep hypoxemia (paO2 28 and 32 mmHg) and a metabolic and respiratory acidosis (pH 7.07 and 7.14) imposed an artificial ventilation with positive end expiratory pressure (PEEP). Hemodynamic study revealed a noncardiogenic edema. In both cases, a cardiac insufficiency was also present : in the first case it's etiology remained unclear, in the second it was a complication of hyperkalemia.

The livers and the pancreas of AKR mice fed with irradiated or non-irradiated wheat flour were homogenized to measure the activities of the follow enzymes : alkaline phosphatase, acid phosphatase, glucose . 6 . phosphate dehydrogenase, amylase. No effect could be demonstrated.