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Biomedical subjects

S Renaud

Publications and source records attributed to S Renaud.

151 records · Page 9Linked to original sources
PubMedDate not supplied

Pathologic gambling in patients with Parkinson's disease.

Patients with Parkinson's disease frequently have depression, anxiety, and obsessive-compulsive disorder. We observed two patients who had episodes of pathologic gambling. At the same time, their Parkinson's disease deteriorated and they initiated self-medication with dopaminergic drugs. In both patients, signs were present of an addiction to dopaminergic medication. Pathologic gambling ceased in these patients after a few months. The significance of an insufficient dopaminergic reward system in patients with stereotypical addictive-like behavior (e.g., pathologic gambling) is discussed in this report. The most likely explanation for this newly recognized behavioral disorder in patients with Parkinson's disease is enhanced novelty seeking as a consequence of overstimulation of mesolimbic dopamine receptors resulting from addiction to dopaminergic drugs.

Antiparkinson Agents↗
PubMedDate not supplied

Whole blood impedance platelet aggregometry and ischemic heart disease. The Caerphilly Collaborative Heart Disease Study.

The Caerphilly Collaborative Heart Disease Study is based on a large cohort of men who were ages 49 to 64 years at the time of the study. We report the results for platelet aggregation measured in whole blood from a subsample of 308 men. The index of sensitivity used was the minimum concentration of adenosine diphosphate that produced a defined degree of impedance change in the Chronolog 560 aggregometer. There was a marked association between aggregation and prevalent ischemic heart disease (IHD). The odds ratios and 95% confidence intervals (CI) for prevalent IHD in men with the most sensitive platelets compared with those with the least sensitive platelets were 3.6 (95% Cl: 1.1 to 12.2) for angina; 7.3 (95% Cl: 2.0 to 24.3) for previous myocardial infarction (MI); and 2.7 (95% Cl: 1.0 to 7.6) for electrocardiogram evidence of ischemia. The confidence limits for these odds ratios are large because of the small sample size, but the estimates of odds ratio are relatively large compared to similar relationships between the traditional risk factors of serum cholesterol, blood pressure, smoking, and prevalent IHD (1.5 to 2.5). A number of factors that might confound the relationships between platelets and IHD were examined, but the associations remained statistically significant when these were taken into account.

Adenosine Diphosphate↗
PubMedDate not supplied

Hormonal contraceptive increases plasma lipid peroxides in female rats. Relationship to platelet aggregation and lipid biosynthesis.

We investigated whether changes in plasma oxidative properties could occur after oral (hormonal) contraceptive (OC) administration in female rats and whether such changes could be responsible for the platelet increase in aggregation and lipid biosynthesis observed with that treatment. Platelets and plasma (platelet-poor) from control and OC (ethinyl estradiol + lynestrenol)-treated rats were prepared separately. Thrombin-induced aggregation of control platelets was markedly enhanced after incubation for 4 (p less than 0.025) to 60 (p less than 0.001) minutes in OC as compared with control plasma. Under the same conditions, platelet lipid biosynthesis was increased also (p less than 0.05 to p less than 0.01), but after 3 hours incubation. The enhanced response of platelets to aggregation induced by OC plasma could be inhibited by adding either glutathione (p less than 0.025), vitamin E (p less than 0.025), catalase (p less than 0.05), or peroxidase + glutathione (p less than 0.005) to plasma or 2,6,di-bis(ter-butyl)p-cresol (p less than 0.05) to platelets before incubation. The peroxidized free fatty acids isolated from OC plasma added to normal platelets induced a 150% (p less than 0.001) increase in the response to thrombin as compared with the fatty acids from control plasma. In addition, the level of malondialdehyde and conjugated dienes was significantly (p less than 0.02 to p less than 0.001) increased in OC compared with control plasma. We conclude that the enhanced formation in plasma of lipid hydroperoxides seems to be the initial event stimulating platelets after OC treatment, at least in rats.

Adenosine Diphosphate↗
PubMedDate not supplied

Increased platelet aggregation after heart transplantation: influence of aspirin.

Accelerated graft coronary artery disease remains the most dramatic complication in long-term survivors of heart transplantation. The main purpose of this study was to evaluate ex vivo platelet function of heart transplant recipients as compared with that of healthy subjects and nontransplant coronary patients. The influence of aspirin, the chief antiplatelet agent, was also evaluated. The heart transplant recipients exhibited a marked platelet hyperaggregation to adenosine diphosphate as compared with the two control groups. In addition, platelets of the heart transplant recipients appeared to be resistant to the inhibitory effect of aspirin. These results could, at least partly, explain the failure of antiplatelet agents to prevent myocardial infarction in these patients.

Adenosine Diphosphate↗