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Biomedical subjects

L Corda

Publications and source records attributed to L Corda.

28 records · Page 2Linked to original sources

Exercise-induced modifications in cardiorespiratory parameters of hypertensive patients treated with calcium antagonists.

The effects of calcium antagonists in reducing blood pressure at rest and during exercise were examined in patients with mild-to-moderate essential hypertension. The haemodynamic effects of calcium antagonists were evaluated at rest and during exercise. We also examined 10 patients with mild-to-moderate essential hypertension taking lacidipine, a new dihydropyridine calcium antagonist (4 mg once a day, at 0700 h). Compared with placebo, lacidipine induced significant mean reductions in 24-h blood pressure (P less than 0.001 for systolic blood pressure; P less than 0.002 for diastolic blood pressure). After 24 h, the blood pressure reductions were still significant (P less than 0.02 for systolic blood pressure; P less than 0.04 for diastolic blood pressure). The heart rate did not change. During dynamic exercise, blood pressure at maximal effort was reduced (P less than 0.01 for systolic and diastolic blood pressure) and the external workload reached at the anaerobic threshold was significantly increased (P less than 0.001), but not at maximum effort. Ventilation and tidal volume were similar at both the anaerobic threshold and peak exercise, while oxygen uptake and carbon dioxide production were increased at the anaerobic threshold (P less than 0.02 for carbon dioxide production) but were similar at peak exercise.

Adrenergic alpha-Antagonists↗

Effect of enalapril on parasympathetic activity.

To evaluate the effect of converting enzyme inhibition induced by enalapril on parasympathetic activity, we studied ten essential hypertensive patients, age range 38-58 years, WHO I-II. Parasympathetic evaluation was obtained by measuring the variation of heart period (VHP) during at least 1 minute of steady-state, regular respiration. VHP was derived from the difference between the mean of all maximum and the mean of all minimum heart periods. The higher the VHP, the higher the parasympathetic control of heart rate and vice versa. VHP was measured supine and with tilting (30 degrees, 60 degrees, 85 degrees). Blood pressure was reduced after 1 month of enalapril treatment, while the heart rate did not change. VHP increased at the end of enalapril treatment compared with placebo: in the supine position it increased from 36 +/- 3.2 ms to 44 +/- 3.5 ms, p less than 0.01. VHP was also increased by enalapril at 30 degrees (p less than 0.05) and 60 degrees (p less than 0.05), while no difference was observed at 85 degrees between placebo and enalapril. A positive correlation was found between supine enalapril changes of VHP and those of systolic and diastolic BP. In conclusion, enalapril seems to increase parasympathetic cardiovascular control in essential hypertensive patients. This result might explain the lack of increase in heart rate that would be expected as a result of the vasodilating effect of enalapril.

Adult↗

[Circadian pressure variability and pressure peaks during treatment of mild to moderate essential hypertension with felodipine].

It is not yet known how blood pressure variability contributes to the vascular changes associated with hypertension, but 2 possibly relevant factors are mean blood pressure levels over time and pressure peaks. It has been observed that patients in whom the variability in 24-hour blood pressure is low have a lower prevalence and severity of target organ damage. We carried out a whole-day continuous intraarterial blood pressure recording (Oxford method) in 12 essential hypertensive patients after a 2-week placebo period and after a 4-week felodipine treatment, administered in an extended release formulation, 10 mg once daily at 7 am. Felodipine significantly lowered systolic and diastolic blood pressure values throughout the 24 hours (p less than 0.005 to 0.001). Also, hourly variabilities of systolic and diastolic blood pressure during whole-day monitoring were significantly reduced (p less than 0.05 to 0.001), evaluated on the basis of the hourly means of standard deviation of systolic and diastolic blood pressure. In addition, felodipine significantly lowered the values of blood pressure reached during both dynamic exercise (bicycle ergometer, p less than 0.001) and isometric exercise (handgrip, p less than 0.001).

Adult↗

Calcium entry blockade, autonomic activity and exercise performance in essential hypertensive patients.

Vasodilator drugs lead to secondary baroreflex mediated chronotropic effects. The aim of the present study was to evaluate long term therapy with nicardipine, a calcium antagonist, on exercise performance and autonomic nervous system activity. Nicardipine was administered to 10 untreated mild-moderate essential hypertensive patients. Isometric (hand grip) and dynamic (bicycle ergometer) exercise, and parasympathetic activity evaluated on the basis of Variation of Heart Period (VHP) during regular breathing were determined. Blood pressure was significantly lowered by nicardipine both supine and standing (p less than 0.001). Heart rate did not change. The increase of blood pressure during isometric and dynamic exercise was similar both before and during nicardipine. The increase of heart rate during dynamic exercise was lowered by nicardipine. The lack of basal supine and standing chronotropic activation and the smaller increase of heart rate during bicycle ergometer could be explained by the observed increase in parasympathetic activity, as indicated by the rise of VHP.

Adult↗

Angiotensin converting enzyme inhibition, parasympathetic activity and exercise in essential hypertension.

Reduced parasympathetic activity has been reported in essential hypertension. Converting enzyme inhibition seems to increase parasympathetic tone. In order to evaluate the effects of enalapril on parasympathetic control of heart rate, the authors studied ten mild-to-moderate essential hypertensive patients (7 F, 3 M), treated for 2 weeks with placebo and for 1 month with enalapril. Compared to placebo, enalapril significantly reduced blood pressure (p less than 0.005 at least, both systolic and diastolic), without any change in heart rate. Enalapril enhanced parasympathetic activity as judged by the increased variation of heart period (VHP) during regular breathing. VHP was derived during continuous ECG recording by the difference between the mean of all maximum and minimum R-R intervals, taken as a measure of respiratory sinus arrhythmia: the higher the VHP, the higher the parasympathetic cardiac influence and vice versa. The response to exercise, used as an index of sympathetic stimulation, was not modified by enalapril: the heart rate peak reached during either static (hand grip) or dynamic (bicycle ergometer) exercise and the slope of the increase in blood pressure were unchanged. Therefore, enalapril appears to increase parasympathetic tone in essential hypertension, without any interference with sympathetic adaptation to stress.

Adult↗

New cycloalkylpyrazoles as potential cyclooxygenase inhibitors.

In this study some cycloalkyl-3-(N-substituted carbamoyl)-1-phenylpyrazoles have been synthesized in order to screen their capability to inhibit human cyclooxygenase. The synthetic pathway is based on the well known property of nitrilimines to undergo 1,3-dipolar cycloaddition reactions. The structures of all the synthesized compounds have been elucidated by means of both analytical and spectroscopic methods.

Cyclooxygenase Inhibitors↗

Effect of enalapril at rest and during isometric and dynamic exercise in essential hypertensive patients.

Vasodilator drugs reduce peripheral vascular resistance but lead to a secondary baroreflex-mediated chronotropic effect. After angiotensin-converting enzyme inhibition, blood pressure falls without associated tachycardia. In a previous study it was observed that enalapril increased vagal tone in essential hypertensive patients. In order to evaluate the effect of enalapril on sympathetic stimulation 10 mild to moderate hypertensive patients were studied during static (hand grip) and dynamic exercise (bicycle ergometer), after 2 weeks of placebo and after 1 month of treatment with 20-40 mg enalapril once daily. Enalapril significantly reduced blood pressure and the rate-pressure product at rest and at peak dynamic exercise. There was no effect on supine and maximal heart rate. Enalapril also significantly reduced blood pressure during hand grip, but did not interfere with the rate of the increase. Thus, enalapril does not seem to interfere with sympathetic adaptation to stress.

Adult↗

[Severe alpha 1-antitrypsin deficiency: cross sectional clinical study].

The aim of this study was to investigate a group of severe alpha 1-antitrypsin deficient subjects. Of the 20 subjects detected, 7 were classified as Index Cases (discovered because they were symptomatic and had pulmonary emphysema or liver disease), while 13 were classified as Non-Index Cases (asymptomatic and discovered because they were relatives of Index Cases or because of the absence of alpha 1 band in serum electrophoresis). They underwent pulmonary function tests, determination of arterial blood gases, lung high resolution computed tomography and lung perfusion scan. All Index Cases were with the ZZ phenotype, indicating a major risk of developing related pulmonary emphysema or liver disease; most Index Cases (71%) were ex-smokers, while among the Non-Index Cases, 46% were smokers or ex-smokers, suggesting that smoking might be the main cofactor in the development of emphysema. Index Cases were older (statistical significance) and mostly male as compared with Non-Index Cases. A statistical significance was observed between the two groups for several lung function parameters (forced expiratory volume in one second, Tiffenau index, residual volume, diffusing capacity of the lung for carbon monoxide, arterial oxygen tension) as a result of a pathological impairment in Index Cases. This underdiagnosed condition merits more attention in order to prevent its complications and to get a better understanding about its diagnosis and management.

Adult↗

[Alpha 1-antitrypsin deficiency: the Brescia clinical study].

In a longitudinal clinical study, two hundred subjects have been evaluated in order to identify alpha 1-antitrypsin deficiency patients. According to their serum alpha 1-antitrypsin levels, they have been divided into three groups: 25 patients with severe deficiency (with both pathological alleles--ZZ, SZ or Z and rare deficiency allele--and, if clinically suggested, to be treated with augmentation therapy), 92 patients with intermediate deficiency (with one pathological allele, to be followed up in order to evaluate the risk to develop deficiency related disease) and 63 healthy subjects (normal alleles MM). They performed lung function test (including cardiopulmonary exercise test and methacholine bronchial challenge) chest X-ray and high resolution computed tomography, blood tests. Severe deficiency patients also performed perfusional lung scan to detect early disorders of blood flow, evaluation of arterial blood gases and liver echotomography. Expiratory flow limitation, the prevalence of vascular disease, the amount of urine elastin products and correlations between the amount of nitric oxide exhaled and bronchial hyperresponsiveness have been also investigated. The study showed that in Brescia county the deficiency is more common than expected and that evaluation of liver and vessels might be as useful as lung function tests. In addition, beneficial effect on local system has been observed. The longitudinal study might permit to detect early organ damage and to eliminate additive risk factors.

Adolescent↗