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Biomedical subjects

M Tanguay

Publications and source records attributed to M Tanguay.

4 recordsLinked to original sources
PubMed1991

Beneficial effects of volatile anesthetics on decrease in coronary flow and myocardial contractility induced by oxygen-derived free radicals in isolated rabbit hearts.

Oxygen-derived free radicals have been implicated in reperfusion injury whereas volatile anesthetics have been shown to enhance myocardial recovery during reperfusion. To explore the mechanism by which these agents improve myocardial recovery, we measured the effect of volatile anesthetics on the free radical-induced reduction in left ventricular pressure (LVP), coronary flow, and endothelium-dependent dilation induced by acetylcholine (Ach). Isolated rabbit hearts were perfused in a Langendorff apparatus. Isovolumetric LVP and coronary flow were measured throughout the study. Oxygen-derived free radicals were produced by the electrolysis (direct current of 0.6 mA) of the perfusate. The following volatile anesthetics were used: halothane 0.5 or 1.0%, isoflurane 0.7 or 1.4%, and enflurane 1.0 or 2.0%. Oxygen free radicals induced a significant decrease in systolic LVP and coronary flow. Pretreatment of the heart with enflurane 1.0 or 2.0%, halothane 1.0%, or isoflurane 0.7% attenuated the effect of the free radicals on both systolic LVP and coronary flow. Free radicals reduced the dilating response induced by 0.1 microM Ach with or without addition of volatile anesthetics. These data suggest that the volatile agents have beneficial effects on the free radical cell damage pathway and that this protection is not related to the preservation of endothelium-dependent dilation.

Anesthetics↗
PubMed1991

Isoproterenol corrects the effects of bupivacaine on the electrophysiologic properties of the isolated rabbit heart.

The purpose of this study was to test the hypothesis that isoproterenol could reverse bupivacaine toxicity. In eight isolated rabbit hearts an electrophysiologic evaluation was performed then repeated during infusion of bupivacaine (1 microgram/mL) alone and bupivacaine plus isoproterenol (1-2 micrograms/mL). Bupivacaine alone increased electrocardiographic intervals (P wave, QRS complex, PR, AV, and QTc interval) and refractory periods of the myocardium and atrioventricular junction as well as the Wenckebach cycle and pacing thresholds. The addition of isoproterenol corrected partially or completely all bupivacaine-induced abnormalities, and decreased sinus cycle length, suggesting a potential therapeutic value in the treatment of bupivacaine intoxication.

Action Potentials↗
PubMed1990

Perception and representation of the Euclidean coordinates in mature and elderly men and women.

Research on gender differences in visuo-spatial tasks has been mostly limited to samples of preadolescents, adolescents, and young adults. In a life span perspective, the present study attempted to complete the available information by submitting mature and elderly men and women to three tasks involving the Euclidean spatial system. Aged 40 to 61, 62 to 72, and 73 to 84, and maximally equivalent across age and sex groups, the subjects performed the Rod-and-Frame Test, the water-level task, and a plumb-line task. Proficiency was expected to decrease with age and to be higher among men. It was found that, whatever their age, men surpassed women in the water-level and plumb-line tasks, whereas no gender difference was obtained on the Rod-and-Frame Test. Irrespective of sex, the oldest subjects were outperformed by the youngest on the Rod-and-Frame Test, while water-level and plumb-line achievement was independent of age. Depression and anxiety scores were not correlated with visuo-spatial performance. Discussion focused on the fact that the present highly homogeneous and selective sample allowed for the valid emergency of a distinctive pattern of gender and age contributions to the use of appropriate vertical and horizontal references once maturity is reached.

Adult↗