Anti-hepatitis C virus epidemiological study in two dialysis centers in Florence.

We studied the prevalence and incidence of anti-hepatitis C virus (HCV) antibodies in 350 patients during 15 months and looked for some risk factors. We found a significant correlation between anti-HCV positivity and length of dialysis treatment and treatment in more than one center. We propose some prophylactic rules.

[3H]-nitrendipine binding in membranes obtained from hypoxic and reoxygenated heart.

We compared the binding properties of [3H]-nitrendipine in heart membranes from normal guinea-pig heart and from hypoxic or hypoxic and reoxygenated heart. The [3H]-nitrendipine binds a single class of high capacity (Bmax 667.2 +/- 105.2) with high affinity (KD 0.14 +/- 0.02) binding sites. By contrast, in membranes of hypoxic and reoxygenated heart the Bmax decreases significantly while it remains unaffected during hypoxia. Xanthinoxidase activity is increased in hypoxic-reoxygenated hearts.

Positive inotropic effect of some taurine-related compounds on guinea-pig ventricular strips perfused with low calcium medium.

Taurine exerts a positive inotropic effect at a low calcium concentration. Of the compounds chemically related to taurine only L-cysteic and 2-aminobenzenesulfonic acid mimic taurine action. Their effect is concentration-dependent and not linked to the restoration of taurine tissue concentration in guinea-pig ventricular strips. Our data demonstrate that: (1) carbon chain length between amino and sulfonic groups is a crucial factor in the development of activity. (2) Substitution of the sulfonic group with other acid functions such as the substitution of the primary amino group or the introduction of the -COOH group onto the beta-carbon brings about a lack of activity.

Cardiac hypoxia and subsequent reoxygenation: sensitivity to L-arginine methylester.

The effect of L-arginine methylester (L-Arg-Me) was studied in the isolated heart of the guinea-pig perfused with hypoxic substrate-free medium for 30 min and subsequently reoxygenated with normal saline solution for 30 min. The administration of L-Arg-Me in basal conditions decreases dose-dependently heart rate without any changes in the myocardial structure. On the other hand, the administration of L-Arg-Me (5-10 mM) decreases ventricular arrhythmias, especially during reoxygenation; in fact ventricular fibrillation is abolished. L-Arg-Me treatment increases the recovery of normal electrical and mechanical activity at the end of reoxygenation and reduces the increase in basal tone. Treatment with 10 mM L-Arg-Me decreases lactate dehydrogenase (LDH) release in the effluent and lysosomal fragility in cardiac tissue, while it does not influence calcium gain. L-Arginine (L-Arg) does not mimic any of the effects of L-Arg-Me.

The protective effects of taurine on hypoxia (performed in the absence of glucose) and on reoxygenation (in the presence of glucose) in guinea-pig heart.

In isolated guinea-pig heart submitted to hypoxia in the absence of substrate and subsequent reoxygenation 1-20 mM taurine decreases LDH release and ventricular arrhythmias, and the recovery of normal electrical and mechanical activity is increased. The taurine effect is dose-dependent, and is not mimicked by beta-alanine. Moreover, taurine reduces the increase in calcium gain of reoxygenated heart.