Clinical science
-
Comment Randomized Controlled Trial Comparative Study Clinical Trial
Increased cationic amino acid flux through a newly expressed transporter in cells overproducing nitric oxide from patients with septic shock.
Increased production of nitric oxide (NO) is thought to be a factor in the pathogenesis of many human diseases - among them the hypotension that often accompanies sepsis. The supply of the cationic amino acid arginine is known to be rate-limiting for NO production. We hypothesized that cationic amino acid transport might be increased in cells producing excess NO from patients with septic shock. ⋯ The activity of the other major cationic amino acid transporter (y+L) was unchanged. The expression of CAT2 mRNA, which encodes a y+ transporter protein, was also increased in these cells. We suggest that CAT2 might be a therapeutic target to prevent excess NO production in sepsis and possibly other human disease states, while leaving basal production unchanged.
-
Randomized Controlled Trial Clinical Trial
The effect of glutamate infusion on cardiac performance is independent of changes in metabolism in patients undergoing routine coronary artery bypass surgery.
In a double-blind randomized placebo-controlled study, the effects of intravenous glutamate infusion on myocardial haemodynamics and metabolism were studied in 22 patients undergoing routine coronary artery bypass graft (CABG) surgery. Immediately after aortic cross-clamp release, an intravenous infusion of a solution of glutamate (125 mmol x l(-1)) at a rate of 1.5 ml x h(-1) x kg(-1) was given over 1 h to 11 patients (G group). The other 11 patients received a placebo infusion (0.9% NaCl) (P group). ⋯ These data show that an intravenous glutamate infusion after routine CABG surgery significantly improved cardiac haemodynamic performance without direct effects on cardiac substrate metabolism. This suggests that a reduction of the afterload via a peripheral vasodilatory effect is the main mechanism leading to the observed changes in haemodynamics. Earlier claims that patients with post-operative cardiac failure show metabolic benefits from the glutamate infusion do not seem to apply to patients undergoing routine CABG surgery.
-
Randomized Controlled Trial Clinical Trial
Effect of intrathecal fentanyl on oxytocin secretion in pregnant women not in labour.
We studied the effects of spinal intrathecal fentanyl on oxytocin secretion in 20 healthy women prior to an elective caesarean delivery at term under spinal anaesthesia. The women were randomly allocated into two groups with respect to spinal anaesthesia. Group I (n=10) received intrathecal bupivacaine (15 mg) plus fentanyl (25 microgram), and Group II (n=10) received intrathecal bupivacaine (15 mg) alone, prior to caesarean section. ⋯ We found no significant differences in plasma oxytocin concentrations of individual subjects before and after intrathecal injection. In addition, there were no significant differences in plasma oxytocin concentrations between the two groups when pooled samples from the subjects were compared for the pre- and post-intrathecal injection phases. We conclude that the spinal intrathecal administration of fentanyl does not suppress oxytocin secretion in pregnant women who are not in labour at term.
-
Randomized Controlled Trial Clinical Trial
Lisinopril improves endothelial function in chronic cigarette smokers.
Cigarette smoking is a pernicious risk factor for the pathogenesis of coronary artery disease, and endothelial dysfunction is an important antecedent event in this process. This is important, as cigarette smoke is directly toxic to endothelial cells. Inhibitors of angiotensin-converting enzyme (ACE) have been shown to improve endothelial function in diabetes and hypercholesterolaemia, and are a promising option in smokers. ⋯ In conclusion, these results indicate that ACE inhibition can improve endothelial function in cigarette smokers. We show that lisinopril improves both receptor-mediated and tonic NO release. The mechanism could be either that lisinopril limits the angiotensin II-induced production of superoxide radicals which would normally inactivate NO, or that lisinopril may increase bradykinin-mediated NO release.
-
Randomized Controlled Trial Clinical Trial
Effects of high-dose glucose-insulin-potassium on myocardial metabolism after coronary surgery in patients with Type II diabetes.
The effects of glucose-insulin-potassium (GIK) on cardiac metabolism have been studied previously in non-diabetic patients after cardiac surgery. Although patients with diabetes mellitus can be expected to benefit most from such treatment, the impact of GIK in diabetic patients undergoing cardiac surgery remains unexplored. Therefore the present study investigates the effects of high-dose GIK on myocardial substrate utilization after coronary surgery in patients with Type II diabetes. ⋯ A decrease in systemic vascular resistance was found both in the control group and in the high-dose GIK group. We conclude that high-dose GIK can be used in diabetic patients after cardiac surgery to promote carbohydrate uptake at the expense of non-esterified fatty acids and beta-hydroxybutyric acid. This could have implications for treatment of the diabetic heart in association with surgery and ischaemia.