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Biomedical subjects

B Trimarco

Publications and source records attributed to B Trimarco.

At least 181 records · Page 10Linked to original sources
PubMed1981

Baroreflex responsiveness in borderline hypertensives: a study with neostigmine.

The baroreflex response to changes in transmural pressure throughout the arterial tree or limited to the carotid sinus was evaluated in ten borderline hypertensives and compared with that observed in ten normal subjects and in ten established hypertensives. Baroreceptor sensitivity was tested by evaluating both heart rate response to phenylephrine-induced increase in arterial pressure and heart rate and blood pressure changes induced by increased neck tissue pressure by means of a neck chamber. The heart rate response to phenylephrine (evaluated by the regression of the R-R interval versus the systolic blood pressure) was depressed both in borderline and established hypertensives as compared with controls. Similarly, the heart rate and the pressor response to increased neck tissue pressure were depressed in both groups of hypertensives. In borderline, but not in established hypertensives, neostigmine administration improved consistently the pressor baroreflex response to increased neck tissue pressure and the heart rate reflex response to both the employed stimuli. These findings indicate that a reduced parasympathetic activity is one of the components involved in the altered baroreflex sensitivity in borderline hypertensives.

Adult↗
PubMed1981

Mechanisms underlying systemic hemodynamic responses to experimental coronary artery occlusion. A preliminary study with hexamethonium.

The hemodynamic changes induced by coronary occlusion were investigated in anesthetized dogs. Coronary occlusion elicited an immediate but transient increase in the systemic blood pressure and in the vascular resistance of the hind limb perfused at constant flow. Thereafter, systemic hypotension and vasodilatation in the perfused region were observed. Vagotomy abolished the initial increase of the systemic and perfusion pressure and reduced significantly the late vasodilator response both systemically and in the perfused hind limb. After the subsequent administration of hexamethonium the vasodilatation in the hind limb was no longer manifest but the fall in blood pressure was unmodified. These results seem to suggest that multiple mechanisms are involved in the hemodynamic response to coronary occlusion.

Animals↗
PubMed1981

[Coronary artery disease (CAD) in females. Coronary arteriographic findings in 34 women and comparison with 184 males with cad].

We studied the clinical, hemodynamic and angiographic findings of 34 women (W) and of 184 men (M) with significant (greater than or equal 50%) CAD. W, compared to M, presented a higher incidence of systemic hypertension (p less than .025), while less frequent were among W smoking habits (p less than .001), history of old myocardial infarction (MI) (p less than .005), and patients in III-IV NYHA class (p less than .025). Left ventricular (LV) dP/dt was higher in W than in M (p less than .005). At coronary arteriography, single vessel disease (SVD) was more frequently found in W than in M (70% vs 23%, respectively, p less than .001); this findings was more evident in patients under 50 years of age (100% vs 30%, respectively, p less than .055). Prevalence of left anterior descending (LAD) over right (RCA) and circumflex (Cx) coronary artery stenoses was more marked in W than in M, especially in patients under 50 years of age (SVD of the LAD in 67% and of RCA in 33% of young W). Poor angiographic run-off of LAD was found in 21% of W, and only in 10% of M. In 2 of the 3 W with poor run-off of LAD operated on, a coronary bypass on the distal LAD was no technically feasible. At left ventriculography, a lower frequency of LV segmental wall motion abnormalities was found in W than in M, especially in patients with no history of MI (p less than .001). In summary, W with significant CAD, compared to age matched M, presented in our experience with a higher frequency of SVD and of LAD stenoses, and with a better LV contractile performance at left ventriculography. Furthermore, in W LAD more frequently showed a poor angiographic run-off. Such findings may bear important implications on the indication and results of coronary surgery in W with CAD.

Adult↗
PubMed1980

Relationship between systolic time intervals and heart rate during atrial or ventricular pacing in normal subjects.

Systolic time intervals (STI) are regarded as good indices of cardiac performance in many heart diseases. It must be considered, however, that they are temporally related to the cardiac contraction cycle and, therefore, may be modified by heart rate changes. Thus, it is necessary to define the possible relationship between STI and heart rate changes. In this study, changes in heart rate were induced by atrial and ventricular pacing. Tachycardia caused a proportional decrease of left ventricular ejection time (LVET) (y=275.142-1.0025 x, r=0.76, p less than 0.001 for atrial pacing and y=298.28-0.691 x, r=-0.75, p less than 0.001 for ventricular pacing, respectively), but did not modify the pre-ejection period (PEP) and the isometric contraction time (ICT) and the electromechanical interval (QS1). These results demonstrate that while LVET must be corrected for the changes in heart rate, no correction of PEP and ICT is necessary.

Adult↗
PubMed1980

Evaluation by multivariate analysis of changes in systolic time intervals during exercise in the supine and upright positions.

In this study multivariate analysis was adopted to establish how simultaneous changes in heart rate (HR), blood pressure (BP) and work load (W) can affect systolic time intervals (STI). Thus, 13 normal volunteers underwent two consecutive exercise stress tests in the supine and upright position on a bicycle ergometer. By multivariate analysis it was shown that, while in the supine position left ventricular ejection time (LVET) is influenced by HR and W (LVET) = 330.6 - 0.76 HR - 0.41 W, F = 224, P is less than 0.001), in the upright position LVET changes are due only to HR variations (LVET = 309 - 0.88 HR, P is less than 0.001). Pre-ejection period (PEP) in both positions is related to HR and W, but this latter has a non-linear influence (supine: PEP = 110.9 - 0.15 HR -0.34 W + 0.0012 W(2), F = 56.4, P is less than 0.001; upright: PEP = 119 - 0.16 HR - 0.5 W + 0.0025 W(2), F = 86.7, P is less than 0.001). Finally, PEP/LVET ratio is correlated both in the supine and upright position with maximal BP, HR and W; however, the influence of HR and BP is different in the two positions (supine: PEP/LVET = 0.259 + 0.00047 BP + 0.00068 HR - 0.00167 W + 0.000013 W(2), F = 5.68, P is less than 0.01; upright: PEP/LVET = 0.201 + 0.0011 HR - 0.00371 W + 0.00016 W(2), F = 4.79, P is less than 0.01).

Adolescent↗
PubMed1980

Long term comparative study of guanfacine and alpha-methyldopa in essential hypertension.

The hypotensive action of guanfacine and alpha-methyldopa has been compared in 30 patients wth moderate essential hypertension. After 2 weeks of placebo treatment, the patients were randomly allocated to a 12 week treatment with either of the two drugs. The treatment was started with guanfacine, 1 mg twice daily p.o., or alpha-methyldopa, 250 mg three time a day p.o. This dose of guanfacine was able to induce a satisfactory control of blood pressure in all patients while the dose of alpha-methyldopa was gradually increased to a predetermined maximum daily dose (2 g) in those patients with unsatisfactory blood pressure control, i.e., systolic blood pressure above 160 mmHg and diastolic above 95 mmHg. Then the two treatments were dicontinued for one week. Both drugs induced a significant reduction of systolic and diastolic blood pressure. However, guanfacine induced a more marked decrease in systolic blood pressure after the 14th day of treatment while the reduction of diastolic blood pressure was significantly higher only at the end of the final wash-out period, thus indicating a longer lasting effect of guanfacine as compared to alpha-methyldopa. Two patients treated with guanfacine developed dryness of the mouth and three of those in the alphamethyldopa group complained of excessive sedation.

Age Factors↗
PubMed1980

[Clinical evaluation of a new antianginal drug: droprenylamine].

In this study the antianginal action of droprenylamine, a cycloaliphatic derivative of prenylamine, was evaluated. Forty patients were included in three groups: in the first group a double blind study was carried out, while in the other two groups, both treated with droprenylamine for a 12 weeks period, were evaluated the effects on workload tolerance or the efficacy in reducing the number of angina pectoris episodes per week and the assumption of nitroglycerine. The double blind study shows that droprenylamine is able to reduce significantly the nitroglycerine assumption. Furthermore, during the 12 week treatment with droprenylamine we can observe a significant reduction of the ST segment depression, at comparable workloads, a significantly increased tolerance to stress test and an early and significant reduction of the angina attacks and, subsequently, of the assumption of nitroglycerine. In conclusion, this drug, which appears free of side effects, may be useful in the treatment of angina pectoris; in particular, the possible association with other antianginal drugs should be evaluated.

Adult↗
PubMed1980

Disopyramide and mexiletine: which is the agent of choice in the long term-oral treatment of lidocaine-responsive arrhythmias? Efficacy comparison in a randomized trial.

Forty patients with serious lidocaine-responsive ventricular arrhythmias were randomly assigned to treatment with either oral disopyramide (100 mg 4 times daily) or mexiletine (200 mg 4 times daily) for 3 weeks. A satisfactory arrhythmias control (greater than 75 % reduction of premature ventricular complexes per minute as compared to the control period prior to lidocaine administration) was achieved in 19 patients in the mexiletine group and in 16 in the disopyramide treated patients. Furthermore, disopyramide failed to maintain the reduction of the number of ventricular extrasystoles per minute obtained with lidocaine, while mexiletine succeeded. Finally, the number of ventricular extrasystoles per minute in the mexiletine treated group was significantly lower than in the other group. Gastrointestinal disturbances were more frequent during mexiletine administration.

Arrhythmias, Cardiac↗
PubMed1980

[The effects of the stellate ganglion electrostimulation on the coronary circulation of the dog (author's transl)].

In this study we have investigated the effects of the stellate ganglion electrostimulation on the perfusion pressure of coronary vascular bed perfused at constant flow. We always observed systemic hypertension and two kinds of response in the coronary district: vasodilatation or vasoconstriction. These responses were blocked by propranolol and phentolamine i.a. administration respectively, while both the phenomena were blocked by i.v. infection of guanethidine. These results seem to suggest that nervous sympathetic stimulation induces catecholamines release by means of either pregangliar adrenergic fibers directed to coronary vessels either postgangliar adrenergic fibres directed to the myocardium. The occurrence of vasodilatation or vasoconstriction could be explained by the prevalent stimulation of myocardial or coronary adrenoceptors.

Animals↗
PubMed1980

[Effects of metoprolol on myocardial performance in hypertensive patients during exercise (author's transl)].

In this study the effects of metoprolol administration (200 mg daily per os) to 20 hypertensive subjects (WHO stage I and II), as a 20-days course, on heart rate (HR), systolic blood pressure (BP) and myocardial performance evaluated by systolic time intervals, were studied both at rest and during exercise. This treatment was able to reduce significantly HR and BP in all the patients, both at rest and during exercise. After the 20 days treatment, the left ventricular ejection time corrected for HR (LVETc) did not show any significant change both at rest and during exercise. On the other hand, the pre-ejection period (PEP) changed at rest in all the subjects studied after metoprolol treatment, but increased significantly during exercise only in patients in the I WHO class and only at the highest work load (at 70 watts, from 63 +/- 2 to 78 +/- 7 msec, P ¿ 0.05). Furthermore, in the same group of patients the maximal work load increased significantly after metoprolol treatment (from 67.5 +/- 6 to 85 +/- 8 watts, P < 0.05).

Adult↗
PubMed1979

Effect of furosemide on plasma concentration and beta-blockade by propranolol.

Although propranolol and furosemide are used together for hypertension, the effects of furosemide on plasma levels and beta-blocking action of propranolol are not known. Ten healthy subjects received propranolol 40 mg orally; the mean plasma propranolol levels in 60, 90, 180, and 300 min were 85 +/- 16, 90 +/- 7, 82 +/- 8, and 58 +/- 8 ng/ml. Propranolol was then given together with furosemide (25 mg orally) and the propranolol blood level was measured. Mean propranolol plasma levels were 106 +/- 11 ng/ml at 60 min, 120 +/- 12 ng/ml at 90 min (p less than 0.01), 102 +/- 8 ng/ml at 180 min (p less than 0.05), and 78 +/- 8 ng/ml at 300 min (p less than 0.01). Six additional subjects were given an infusion of 1 microgram/min isoproterenol increased by 0.5 microgram/min every 2 min until the heart rate rose by 25% after oral administration of furosemide 25 mg. This procedure was repeated after propranolol (40 mg orally) and propranolol with furosemide (25 mg orally). The amount of isoproterenol which raised the heart rate by 25% was 2.6 +/- 0.3 micrograms after furosemide alone and 17.7 +/- 2 micrograms after propranolol (p less than 0.01). After propranolol with furosemide the dose of isoproterenol required to elevate heart rate by 25% was 109 +/- 15 micrograms (p less than 0.001).

Adolescent↗
PubMed1979

Potassium sparing effect of amiloride in patients receiving diuretics: a quantitative study.

This study was undertaken in order to assess the K+ sparing ability of amiloride. Thirty patients with liver cirrhosis and ascites or congestive heart failure were divided into three groups and treated with amiloride (Group A), hydrochlorothiazide (Group B) and amiloride plus hydrochlorothiazide (Group C) for 15 days. In all groups there was an increased diuresis while only in group A and C there was a statistically significant rise of K+ serum levels and a slight increment of K+ urinary loss. Total body K+ evaluated by 42K increased in group A and C while decreased in group B. Our results seem to confirm that amiloride has a mild diuretic action with a powerful K+ sparing capacity; amiloride is also able to counterbalance and reverse hydrochlorthiazide induced K+ urinary loss.

Adult↗