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Biomedical subjects

R Ferrari

Publications and source records attributed to R Ferrari.

At least 379 records · Page 21Linked to original sources
PubMed1987

The effects of intravenous nifedipine on cardiac hemodynamics and contractility in patients with coronary artery disease in the presence or absence of beta adrenergic blockade.

We studied the acute effects of intravenous nifedipine on hemodynamics and left ventricular function of CAD patients without previous treatment (group 1) and of 10 CAD patients receiving acebutolol (9 mg/kg daily) and who had been shown to be adequately beta blocked (reduction in heart rate by 25%) (group 2). Intravenous nifedipine (15 micrograms/kg) significantly reduced systemic peripheral resistances in both groups: this was associated with decreased systolic blood pressure and increased left ventricular cardiac output with a slight nonsignificant increase of ejection fraction. There was a significant increase in heart rate in both groups, the chronotropic response to nifedipine being attenuated in patients receiving acebutolol. Left ventricular end-diastolic pressure did not change in the first group, but it was significantly decreased in the second group, with a concomitant increase of end-diastolic left ventricular volume, suggesting an amelioration of diastolic compliance. The effect of nifedipine on intrinsic myocardial contractility was quite different, depending on the presence of beta adrenergic blockade. When given to patients of group 1, nifedipine significantly increased dP/dtmax, Vcemax, and Vmaxd. The same indices, however, were significantly depressed when nifedipine was given to the patients of group 2 receiving acebutolol. This study shows that intravenous nifedipine can be usefully administered to patients with coronary artery disease who have been on adequate beta-blocking doses of acebutolol with relative safety. Under these conditions nifedipine increases cardiac output in association with arterial dilation, despite evidence for a negative inotropic effect. These data also suggest that such an intrinsic negative inotropic effect would normally be masked by compensatory sympathetic activity.

Acebutolol↗
PubMed1987

On the presence of a peculiar alpha rhythm in the olfactory tubercle of waking armadillos.

A very regular 8-12 rhythm was found in the olfactory tubercle of the armadillo Chaetophractus villosus. The rhythm was observed during wakefulness. Considerable sinusoidal activity was also observed not only during wakefulness, but during synchronized (slow) and desynchronized (paradoxical) sleep. The significance of this novel rhythm is discussed together with considerations that establish an important difference between it and the other 'alpha rhythms' known.

Alpha Rhythm↗
PubMed1987

Mechanism of myocardial protective action of dilazep during ischaemia and reperfusion.

The aim of this study was to investigate if dilazep is able to reduce with a direct protective action on the myocardium the deleterious effects caused by ischaemia and reperfusion. For this purpose we used an isolated rabbit heart preparation. The hearts were either perfused aerobically or made totally ischaemic for 60 min (by abolishing coronary flow) or made ischaemic for 60 min and then reperfused for 30 min. Ischaemic and reperfusion damage was measured in terms of alteration in mechanical function, lactate and CPK release, mitochondrial function and tissue content of Adenosine Triphosphate (ATP), Creatine Phosphate (CP) and calcium. Dilazep (10(-5) M) was administered in the perfusate either 20 minutes before ischaemia or only during post-ischaemic reperfusion. Ischaemia induced a decline of the endogenous stores of ATP and CP, followed by an alteration of calcium homeostasis with increase of diastolic pressure, mitochondria calcium overload and impairment of the oxidative phosphorylating capacities. On reperfusion, tissue and mitochondrial calcium increase the capacity of the mitochondria to use O2 for state III respiration was further impaired and the ATP-generating capacity reduced. Diastolic pressure increased and there was only a small recovery of active tension generation associated with massive CPK release. Administration of dilazep before ischaemia induced a negative inotropic effect which, in turn, resulted in a slowing of the rate of CP and ATP depletion during ischaemia. This protected the hearts against the ischemic, and reperfusion-induced decline in the ATP-generating and O2-utilizing capacities of the mitochondria. In addition, there was a less marked increase in tissue and mitochondrial Ca++, CPK and lactate release were reduced and the recovery of developed pressure on reperfusion was significantly increased. Administration of dilazep during reperfusion failed to modify the exacerbation of ischaemic damage caused by the readmission of coronary flow. These data suggest that dilazep benefits the ischaemic myocardium via an ATP sparing action.

Adenosine Triphosphate↗
PubMed1987

Effects of verapamil and nifedipine on rate of left ventricular relaxation in coronary arterial disease patients.

We have evaluated the effects of nifedipine and verapamil on rate of left ventricular relaxation in 26 patients having coronary arterial disease with normal ejection fraction and normal left ventricular contractility. None of the patients had myocardial infarction. All patients showed normal contractile indices and abnormally high values of T constant, neg, dP/dt and left ventricular protodiastolic pressure, suggesting an impairment of left ventricular relaxation. Nifedipine, injected intravenously (15 micrograms/kg) in 14 patients induced a significant reduction of afterload parameters and an increase of contractility. Nifedipine also improved left ventricular relaxation, as it induced a reduction of the T constant from 42 +/- 2 msec to 33 +/- 2 msec (P less than 0.01). It induced a tendency to a reduction of negative dP/dt and protodiastolic pressure without reaching statistical significance. Verapamil, injected intravenously in the remaining 12 patients (0.1 mg/kg as a bolus followed by chronic infusion of 0.005 mg/kg/min for 3 min) induced a reduction of the T constant from 43 +/- 10 to 37 +/- 6 msec (P less than 0.01). It reduced the negativity of dP/dt from 2302 +/- 273 to 2021 +/- 252 mm Hg/sec (P less than 0.05) and of left ventricular protodiastolic pressure from 3.2 +/- 1.4 to 1.5 +/- 1.1 mm Hg (P less than 0.01). Verapamil, like nifedipine, reduced the afterload parameters although to a lesser extent. It did not substantially affect the left ventricular contractility. These data suggest that abnormalities of left ventricular relaxation may precede changes in systolic function and that nifedipine and verapamil favourably modify the indices of left ventricular diastolic function in patients with coronary arterial disease.

Blood Pressure↗
PubMed1987

Myocardial metabolism during intracoronary thrombolysis. Two illustrative cases.

Arterial and coronary sinus difference for potassium, lactate, glucose, free fatty acids and creatine kinase was measured every 5 minutes in two patients undergoing successful intracoronary thrombolysis of left anterior descending occlusion. In the first patient, reperfusion, 160 minutes after the onset of pain, was followed by a transient and limited release of creatine kinase in the coronary sinus, improvement in the electrocardiogram and restitution of left ventricular contraction. In the second patient, reperfusion 365 minutes after the onset of pain, was also accompanied by a limited release of creatine kinase. Reocclusion of the left anterior descending coronary artery, however, necessitated further thrombolysis which led to a massive release of creatine kinase and permanent loss of wall-motion. It is suggested that, in this case, reperfusion damage had occurred. The arteriovenous differences showed a wash-out of potassium and lactate during reperfusion in each case. The interpretation of the entire sequence of arteriovenous changes, however, could be shown to depend critically on the state of regional perfusion.

Blood Glucose↗
PubMed1987

Effects of calcium entry blockers not connected with calcium channels inhibition.

We tested the effects of calcium entry blockers (verapamil, nifedipine, diltiazem) in comparison with nitroglycerin to investigate their inhibitory mechanisms of smooth muscle contraction not connected with the calcium blockade through calcium channels. The experiments were carried out by using isolated rabbit aorta strips in both normal and Ca2+-free solutions. Our results indicate that nitroglycerin and calcium entry blockers act on different calcium pools; the differences observed among calcium entry blockers suggest that other factors, different from calcium channels blockade (alpha-adrenergic block, unspecific effects), may be responsible for their inhibitory effect when high doses are employed.

Angiotensins↗
PubMed1987

Release of atrial natriuretic peptide-like immunoreactive material during stretching of the rat atrium in vitro.

In 1979 De Bold showed that the numbers of atrial specific granules varied with changes in water and electrolyte balance of the whole animal. Two years later, he showed that atrial extracts had a natriuretic effect. The active principle has now been identified as a polypeptide formed by cleavage of a larger precursor molecule. The rate of release of atrial natriuretic peptide-like immunoreactive material by the isolated, perfused rat heart has been shown to be increased when the right atrial pressure is raised. The mechanism of release remains, however, unknown. We describe, here, experiments which show a transient release of atrial natriuretic peptide-like immunoreactive material from isolated rat atria subjected to a constant load in an organ bath. The release appears to be specific in that it is not accompanied by a parallel release of other peptides contained in nerve fibres or of creatine kinase contained in myocytes.

Animals↗
PubMed1987

Efficacy and tolerance of ceftazidime in the treatment of post-operative respiratory tract infections.

Ceftazidime proved particularly effective in the treatment of acute respiratory tract infections arising in the immediate post-operative period, affording complete clinical cures in 88.8% of cases and a substantial improvement in the pathological picture in the other 11.2% of cases treated. The authors also draw attention to the excellent tolerance of the antibiotic, as evaluated on the basis of liver and kidney function and blood chemistry parameters and the total absence of adverse reactions.

Adult↗
PubMed1987

Improved procedure for determining glutathione in plasma as an index of myocardial oxidative stress.

Glutathione plays an important role in the detoxification processes of electrophilic metabolites of xenobiotics and oxygen free radicals, such that release of reduced and oxidized glutathione into the plasma is considered a reliable index of oxidative stress. However, reduced glutathione in plasma undergoes spontaneous autoxidation, with mixed disulfide formation. We developed a new, simple, quick method to overcome this problem by treating the blood, immediately after collection, with thiol reagents. We add 5,5'-dithiobis(2-nitrobenzoic acid) and N-ethylmaleimide to the blood before determination of total and oxidized glutathione, respectively. We find the proposed assay useful for investigating oxidative stress in clinical situations.

Adult↗