PubMed Health⌕ Search

Biomedical subjects

G de Saint-Blanquat

Publications and source records attributed to G de Saint-Blanquat.

At least 19 recordsLinked to original sources
PubMed1991

[Pesticides in human food].

Pesticides represent a good picture of the Risk-Profits equation. Owing to their pest-destroying properties they are required in the mondial food but they remain inevitably present as residues in foods from both animal and vegetal origins. Therefore due to their biological activity a problem arise in Public Health. Actually, the investigations carried out on food contamination show that--except in pinpoint cases--pesticides seem less worrying that other contaminant such as heavy metals or mycotoxins. However questions remain concerning the consequences of repeated ingestion at low levels, the extrapolation for human of experimental results from animals, the simultaneous presence of several active compounds, their consequences on the food-value and the relationship between toxicity and nutritional or pathological states.

Food Contamination↗
PubMed1991

[Package contaminations].

In this chapter, the authors consider the problems originating from packaging for foods and the possible risks of contamination. The methods available for evidencing the possible migrations from package to food are considered. Dealing with package safety, toxicological tests (animal, cells...) are described. Then, the different classes of materials, as well that are usual (wood, paper, cardboard, glass, ceramic, metal, ...) as the new materials (plastic, elastomer, ...) are described. The authors emphasis the importance of package and of its development in food industries. Safety control from toxicologist is critical.

Food Contamination↗
PubMed1988

Rilmenidine (S 3341) and the sympathoadrenal system: adrenoreceptors, plasma and adrenal catecholamines in dogs.

1. The effects of rilmenidine, a new alpha 2-adrenoreceptor agonist with antihypertensive properties, were investigated on plasma catecholamines, blood cell adrenoreceptors and adrenal medullary function. 2. In conscious sino-aortic denervated (SAD) dogs, rilmenidine (1 mg kg-1 orally for 2 weeks) significantly reduced both blood pressure and heart rate when compared with placebo treatment. The drug decreased plasma noradrenaline and adrenaline levels and corrected the decrease in leucocyte beta-adrenoreceptors observed in placebo-treated SAD dogs. There was no change in platelet alpha 2-adrenoreceptors. 3. In anaesthetized normotensive dogs, rilmenidine (0.1 and 0.3 mg kg-1 i.v.) induced a dose-dependent decrease in both cardiovascular parameters (blood pressure and heart rate) and catecholamine release from the adrenal medulla. 4. The present study shows that rilmenidine decreases sympathetic tone mainly by an action on the adrenal medulla. In addition, its ability to lower blood pressure in SAD dogs, i.e. a model of hypertension in which high sympathetic tone is present, indicates that rilmenidine may also depress other parts of the sympathetic nervous system.

Adrenal Medulla↗
PubMed1987

Action of phosphine on production of aflatoxins by various Aspergillus strains isolated from foodstuffs.

Phosphine is a food fumigant, used until now as an insecticide and rodenticide. The present work researches the action of phosphine treatment on growth and aflatoxin production of 23 Aspergillus strains. Production of aflatoxins B1, B2, G1, and G2 decreased in almost all cases by a ratio of 10 to 100. Phosphine treatment therefore seems favorable to prevent growth of various Aspergillus strains, in the context of keeping food safe.

Aflatoxins↗
PubMed1984

Lipid composition of the synaptosome and erythrocyte membranes during chronic ethanol-treatment and withdrawal in the rat.

Male Sprague-Dawley rats were intoxicated by inhalation of ethanol vapor for 21 days. This allowed high tolerance to the hypnotic effect of ethanol and withdrawal syndrome to be developed. The chronic intoxication brought about modifications of the synaptosome and erythrocyte membrane lipid composition which were not due to the reduction in food intake that parallels intoxication. The fatty acid composition of the phospholipids was modified but the level of cholesterol and the level of phospholipid remained unchanged. The modifications concerned the levels of linoleic (18:2) and arachidonic (20:4) acids which decreased in the synaptosomes. In the red blood cell membranes, ethanol affected the levels of the octadecenoic acids (18:1) which rose, and linoleic acid (18:2) which fell. These disturbances were present when the withdrawal syndrome was at its highest and also 3 days after withdrawal when the signs of hyperexcitability were no longer visible in the animal. Modifications in the brain membrane lipid composition parallel the behavioral tolerance to ethanol; however the present results show that the apparent readaptation of the central nervous system to withdrawal of alcohol occurs earlier than the return to normal of the membrane lipid modifications.

Alcoholism↗
PubMed1983

The gastro-intestinal metabolism of ethanol in the rat. Effect of chronic alcoholic intoxication.

By collecting the blood coming exclusively from the stomach or intestine of rats, it has been shown that ethanol can be oxidized in the digestive mucosa on the basis of the appearance, during its absorption, of acetaldehyde and acetate. This has been shown to be the result of the action of alcohol- and aldehyde-dehydrogenases present in these tissues. The metabolic ability of these enzymes was tested after chronic alcoholic intoxication in association with various treatments with "anti-alcoholic" drugs. The modifications observed correspond to the effects of the treatments on the levels of the enzyme activities but are less clearcut in the in vivo conditions.

Acetaldehyde↗
PubMed1980

[Toxicologic and nutritional aspects of nitrates and nitrites].

The toxic action of nitrates and nitrites has often been summarized by methemoglobinemia and nitrosation of amines inducing carcinogenic effects; these two impacts are spectacular, but they hide varying more or less insidious actions recently studied and perceived. In the NO3/NO2 couple, it is accepted that especially nitrite ion lays down a toxicological problem, probably because of its particular chemical reactivity: nitrite ion, which is the base of nitrous acid HNO2 (pKa = 3.36) can react with many functional groups from dietary or endogenous origin; it is also a reducing agent, only oxidable by chemical oxidants or adequate enzyme systems; at the same time it is an oxidant for many reduced substrates. These different possibilities explain the chemical complexity of these compounds and almost their reactivity in biological various media with toxicological implications (modification of the redox state). In man, the presence of nitrates in the digestive tract may result in nitrite formation, because nitrate-reductase from bacterial or enterocyte origin; more particularly in stomach, nitrites are characterized by a great instability imputable to the low pH of gastric juice and to secreted factors which accelerate phenomena; at the same time, nitrates and nutrites exercise opposite effects on gastric secretion (volume, acidity, pepsin) and on gastric mucosal irrigation: while nitrates increase these different parameters, nitrites reduce secretory activity but correlations between secretion and irrigation show that nitrates induce a deep modification of hydric compartment whereas nitrites rather react through cellular anoxy. In intestine, nitrates and chiefly nitrites are very quickly absorbed by a passive mechanism and they are characterized by an extrahepatic cycle; nitrates and nitrites are also eliminated in large quantities by kidneys, and nitrates have a very high diuretic effect: these NO3- ions move Cl- ions, inducing a Na+ waste, a decrease in extracellular space and an alkalosis; this diuretic action of ionic origin is moreover increased by a rise in glomerular blood flow facilitating filtration; these compounds therefore present vasomotor effects, probably by an action on catecholamines whose metabolism is modified. Last, nitrates are suspected to be responsible for reproduction troubles, thyroid dysfunction, perturbances of vitamins availability and nutritional effects. Most of the impacts of nitrates and nitrites are now well known, but their cellular of molecular action is not clear, and as a result there is a suspicion in regard to these products very widely present in food.

Animals↗
PubMed1980

[Nutritional and toxicologic impact of nitrates and nitrites administered chronically (6 months) in the rat].

It has been made a toxicological, nutritional and histological study of rats fed ad libitum, for six months, with a diet containing respectively (per 100 g of dry food): 0, 0,5 and 5% of NO3- ion and 0, 0,05 and 0,5% of NO2- ion. For each group of treated animals we have paired groups of control animals fed with a diet including the same doses of sodium as NaCl. At the highest dose studied, nitrates and nitrites induce a significative loss of weight during two first months of intoxication, but they do not impair noticeably the classic nutritional parameters of nitrogen metabolism, established at different periods of intoxication (0, 2, 4 and 6 months). Besides, dietary ingestion of relatively important quantities of NO3- and NO2- ions does not induce notable modifications of body composition and blood formula, showing an important adaptation of treated animals. Last, histological observations give evidence to a certain irritation (mucus, oedema) of the anterior section of digestive tract (especially stomach with nitrites), some attacks (essentially with nitrates) of thyroid gland (possible competition with iodine) and kidneys (increased diuresis); but the essential impact, with nitrates and nitrites, is situated at the spleen level, with an important liberation of iron and the trace of haemorrhagic zones, testifying to the chronic struggle of treated animals against methemoglobinemia.

Animals↗
PubMed1978

[Experimental inflammation after subchronic treatment with Nabam in the rat].

Inflammatory response to turpentine-induced granuloma components was studied in rats receiving 100 ppm Nabam (N,N'--ethylene--bis)dithiocarbamate) disodium) with food for one month. Results of nutritional, clinical and histopathological studies showed no modification. However, administration of Nabam modified the amounts of various mucopolysaccharides, which are important components of the inflammatory response; the amounts of total mucopolysaccharides, glucuronic acid mucopolysaccharides and sialic acid mucopolysaccharides were obviously lowered in treated animals, a symptom of impairment of the inflammatory response. When most classical means of investigation provide only little information, this test could allow toxicologists and nutritionists to evaluate the organisms reactivity to insidious toxic aggression.

Animals↗
PubMed1978

[Dietary protein levels, and experimental inflammation in the rat].

The inflammatory response was studied using the contents (mucopolysaccharides and collagen of granuloma induced by turpentine in rats fed for 28 days after weaning), with semi-synthetic, isocaloric diets containing 0, 3.5, 9, 26 or 81% protein in the form of casein or with a laboratory chow. When the wet and dry weights and the water content of the granuloma are expressed in absolute values they show a substantial drop when the protein intake is low or excessive. If however the wet weight of the granuloma is expressed per 100 g of body weight, the differences become no longer significant, hence the importance of the nutritional state of the animal at the time of investigation. Using this test of the anti-inflammatory action of substances, it is necessary to differenciate between actual anti-inflammatory action and direct or secondary effects of the substance on the growth and behaviour of the animal. The levels of mucopolysaccharide drop in rats fed on hypo or hyper-proteinic diets, this would seem to be a sign of the decrease in the intensity of the anti-inflammatory response. What is more, the collagen itself undergoes modifications; there is a shift towards greater solubility of the fractions which would seem to indicate that a drop or a increase in the protein intake brings about a change in the processes of reticulation and maturation of the collagen; several hypothesis can be put forward to explain this phenomenon.

Animals↗
PubMed1978

[Nutritional and toxicological impacts of administered inorganic tin for six months in rats (author's transl)].

An experimentation of intoxication by stannous chloride has been realized in the rat. Two groups of animals have been fed ad libitum, during six months, with a diet containing respectively 0,4 and 0,8 g of tin (SnCl2) for 100 g of dry food. By gamma radioactivity measurements (with 113Sn used as a tracer), it results that this metal does not practically clear the digestive barrier. All the treated animals are characterized by a ponderal evolution obviously lower than temoins. At the end of treatment, tin entails a significative diminution of hematocrit, hemoglobin and serous iron, particularly at the highest dose studied. The essential impact remains that tin induces a total irritation of gastro-intestinal tract, proved by histological investigations.

Animals↗
PubMed1976

[Variations in circulating bradykinin and its precursor during treatment with ethanol and disulfiram in the dog].

Blood variations of bradykininogen and bradykinin have been measured in the Dog after single or combined treatments with ethanol and disulfiram. Ethanol only induces hyperbradykinnemia and chronic disulfiram decreases plasmatic level of bradykinnogen without modifying bradykinn. During associated treatment disulfiram-ethanol, physiological disturbances are observed in bradykinin formation; these disturbances can explain partly vasomotor reaction following treatments.

Animals↗
PubMed1976

[Formation of nitrites from nitrates in the digestive tract].

The authors performed in vitro incubations of gastrointestinal mucosae and contents in the rat, under anaerobiosis, in the presence of nitrates. Nitrate disappearance and nitrite appearance amounts were measured in the different incubation media. From these works it follows that a certain quantity of nitrates are actually reduced to nitrites specifically by the ileo-caecal microflora of rats and perhaps, to a lower degree, by the action of a nitrate-reductase which may occur in the digestive mucosae. Moreover, the authors carried out in situ perfusions into the small intestine of rats, by adding nitrates to the perfusion liquid at a concentration of 400 mg per litre. It was thus demonstrated that the nitrate-absorbing kinetics is very rapid but those nitrates do not gather in the blood; besides, the presence of nitrites in the perfusion medium indicates a possible nitrate reduction in the intestinal gut.

Anaerobiosis↗