Biomedical subjects
Publications and source records attributed to R Molimard.
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Nicotine was investigated for its mnemonic effect in a two trials object recognition task. In the first trial, two copies of the same object were presented. In the second trial (24 h after), one of the familiar object and a new object were presented. The time spent exploring the new object by control rats was not significantly different from the exploration time of the familiar object, indicating that they did not remember the familiar object. Rats injected with nicotine before the first trial, after the first trial or before the second trial spent more time in exploring the new object than the familiar one at the second trial. These results suggest that, in normal rats, acute nicotine enhances acquisition, consolidation and restitution of the information in an object recognition task.
This paper reviews the current state of knowledge about smoking after myocardial infarction in smokers. After presenting results emphasizing the value of post-infarction smoking cessation, all of the predisposing factors to smoking cessation are analysed. The objective of this review of the literature is to recognize these factors in order to more precisely define the various medical, psychological and social aspects of an assistance programme adapted to post-infarction smoking cessation.
Smoking is the leading preventable cause of death. Approximately 40% of Europeans now smoke. Many smokers want to stop but do not make the attempt, and of those who try, most are unsuccessful. Primary care health providers can help their patients to stop by using brief behavioural and pharmacological interventions. Specialised smoking cessation clinics can support selected patients referred by primary care providers. This report reviews intervention techniques for health care providers, which, in combination with effective legislative and educational interventions, can significantly reduce the prevalence of smoking.
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As failure to induce behavioral dependence to oral nicotine (0.31 mM) might be caused by taste aversion. Sixteen rats were presented nicotine around the taste aversion threshold (0.025 mM then 0.05 mM) as only source of fluid for 10 weeks. Eight of them had undergone portacaval anastomosis (PCA) to increase bioavailability of nicotine by preventing liver first-pass. Weekly choice sessions between nicotine and water demonstrated neither aversion nor preference for nicotine. In 10 control and 11 PCA rats accustomed to drink 0.31 mM nicotine, plasma nicotine was determined after 3 ml/kg intragastric nicotine-solution. In both groups, 0.05 mM nicotine did not lead to detectable levels but 0.31 mM nicotine led to peak levels higher than seen in man after smoking. Similar levels were recorded after spontaneous nicotine drinking in 8 isolated and 18 grouped normal rats accustomed to 0.31 mM nicotine. Drinking nicotine for at least 10 weeks did not induce behavioral dependence in these rats. This cannot be explained by poor nicotine bioavailability by oral route.
Tobacco dependence prevents any reduction in morbidity and mortality related to smoking. Nicotine is widely regarded as responsible for this dependence process. It stimulates ubiquitous cholinergic receptors thus resulting mainly in catecholamine release. The causal role of nicotine in inducing and maintaining tobacco dependence is not so obvious as that of drugs responsible for other addictions. Animal models that have been described are not convincing. Smokers tend to change their smoking patterns so as to keep blood nicotine levels constant when nicotine yields of cigarettes are manipulated. This "nicotine titration phenomenon" is a strong argument in favor of them craving for nicotine. However, other components, such as tar, vary correlatively. Nicotine gum helps to quit smoking, but few people become gum-addicted. A better knowledge of the tobacco components that may induce dependence is needed to understand its neurochemical mechanisms and to provide the tobacco industry with adequate information for manufacturing less hazardous products.
Closely similar to the mineral composition of bone, di- and tricalcium phosphates would seem of interest as oral calcium supplement; unfortunately, they are commonly regarded as non-absorbable because of their insolubility. Seven elderly patients received a constant regimen of 1500 mg of calcium a day, supplied either by diet alone, or by a hypocalcemic diet (Ca = 500 mg) supplemented with di- or tricalcium phosphate (Ca = 1000 mg). Calcium balance remained positive under the calcium phosphate treatment. Inexpensive, stable and well-accepted by patients, these salts, especially tricalcium phosphate, deserve to be evaluated in view of their use for therapy and mass prevention of senile osteoporosis.
The plasma amino acid pattern of cirrhotic patients was determined before and after 24 h of continuous infusions of glucose, ornithine alpha-ketoglutarate (O alpha KG), ornithine chlorhydrate (ORN HCl) and sodium ketoglutarate (alpha CGNa). Before treatment, leucine, isoleucine, valine and glutamine levels were low. Tyrosine and methionine levels were high. (See formula in text) was low. Glucose infusions had no effect. O alpha KG increased levels of leucine, isoleucine, valine, alanine and arginine. Threonine, serine, glycine, aspartic acid, methionine, hemicystine, tyrosine and phenylalanine were significantly lowered. (See formula in text) increased. ORN HCl and alpha CGNa did not induce similar changes.
An apparatus is described allowing multichannel connection with unrestrained animals without using joints. The twisting of the connection lines caused by the rotation of the animal in its cage is detected by means of a torsion wire connected to an electronic device. This provokes a temporized rotation of the bottom of the cage in the opposite direction in order to untwist the lines.
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This study was undertaken to assess the role of the hepatic innervation in the short-term regulatory mechanisms of food intake. A liver denervation was performed in male Wistar rats: the liver was entirely freed from the surrounding organs, its vessels (with the exception of the hepatic veins) and the bile ducts were stripped. Controls consisted of two groups of liver-denervated rats in which sympathectomy or vagotomy were carried out. A continuous recording of food intake was performed in a third group. The complete absence of the hyperglycemic response to trauma in adrenalectomized liver-denervated animals was taken as evidence of functional sympathectomy of the liver. The disappearance of a vagovagal reflex--heart rate variation brought about by a glucose injection into the portal vein--was taken as evidence of functional vagotomy. The analysis of the recorded feeding patterns of liver-denervated and sham-operated animals showed that, in rats, this liver denervation did not affect in any way the feeding behavior.
Two controlled trials were performed successively to evaluate the effect of high doses of oral pyridoxine on brain performance in man. In trial I, medical students volunteered to take 100 mg, 500 mg of pyridoxine a day or placebo for 10 days. A digit coding test was performed before, and at the end of the treatment period and a third 15 days later. The improvement of performance from the first to the third test (learning effect) was significantly better in the placebo group than in the B6 treated groups. This could be attributed to memorization of skills. Trial II was performed in obese patients starting a low calorie diet in whom vitamins are routinely prescribed. Performance in a work recognition test and in a visual retention test was lower for the group receiving 1 g of pyridoxine a day. Thus, high doses of oral pyridoxine are likely to impair memorization in man. Disturbances of neuro-transmitter metabolism such as increase of GABA production might explain the effect. As the benefit of high doses of pyridoxine has not been well-documented and as the study has suggested that undesired effects may indeed exist, the widespread use of such doses is questionable.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.