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Biomedical subjects

F Rabbia

Publications and source records attributed to F Rabbia.

At least 37 records · Page 2Linked to original sources
PubMed1997

Fourier analysis of circadian blood pressure profile in secondary hypertension.

Different types of statistical methods have been used for circadian blood pressure (BP) rhythm analysis in secondary forms of hypertension. In the present study, we used the two-step statistical approach by Fourier analysis with four harmonics for the parametrization of the diurnal BP pattern in secondary hypertension. In 43 essential hypertensives (EH), eight patients with aldosterone producing adenoma (APA), 25 with idiopathic hyperaldosteronism (IHA), four with glucocorticoid remediable hyperaldosteronism (GRH) and seven with renovascular hypertension (RVH), 24-h ambulatory BP was measured. The diurnal BP and heart rate (HR) rhythm was present in more than 70% of patients with secondary hypertension, without significant differences with EH and despite the attenuation in the degree of the nocturnal BP fall. In conclusion, the statement that secondary hypertension is characterized by an abnormal diurnal rhythm of BP is a gross over-simplification. Our findings suggest that the two-step method with four harmonics Fourier analysis may represent a useful method and a more complete statistical approach to providing circadian parametrization of the 24-h profile in secondary hypertension.

Blood Pressure↗
PubMed1996

Weighted Fourier analysis of blood pressure curves after lisinopril versus atenolol administration in young hypertensives.

OBJECTIVE: To evaluate and compare the effects of lisinopril versus atenolol administration on the diurnal blood pressure profile and the nocturnal blood pressure fall in young mild-to-moderate essential hypertensives.METHODS: Thirty patients were studied. After a 2-week placebo run-in period, they were single-blind randomly assigned to receive 20 mg lisinopril or 100 mg atenolol. Using a SpaceLabs 90207 device, their ambulatory blood pressure was measured before and after 12 weeks of therapy. The readings were analysed using Fourer series with four harmonics. RESULTS: Lisinopril and atenolol administration significantly decreased office and ambulatory blood pressure values compared with the placebo period. The daily blood pressure curves obtained from Fourier analysis showed that the circadian rhythm was not altered by lisinopril and atenolol administration. From the night:day ratio for the nocturnal blood pressure fall, we found that atenolol administration minimized the average night-time blood pressure dip by increasing the number of non-dippers. In contrast, lisinopril administration did not modify the day-night difference, preserving the nocturnal blood pressure fall. CONCLUSION: Lisinopril and atenolol administration as a first-step treatment of young essential hypertensives produced comparable degrees of diurnal control of arterial pressure. The blood pressure fall at night in patients treated with atenolol was slightly less than that found with lisinopril treatment.

Journal Article↗
PubMed1995

Spectral characteristics of heart rate and blood pressure variability in primary aldosteronism.

A disturbance of the autonomic cardiovascular function has been postulated in primary aldosteronism as a possible mechanism for hypertension. Using the method of spectral analysis of heart rate and blood pressure variability, the aim of this study was to assess sympathovagal interactions modulating cardiovascular function and baroreflex control in patients with primary aldosteronism. Seventeen patients (7 with adenomas and 10 with idiopathic hyperaldosteronism) and a control group of 11 essential hypertensives (EH) and 10 normotensive subjects were studied. Continuous finger blood pressure was measured using a Finapres device and heart rate was measured using an electrocardiographic monitor. The studies were conducted in each patient for 20 min in the supine position and 10 min during a passive head-up tilt to 60 degrees. The low frequency and the low frequency-to-high frequency ratio of systolic and diastolic blood pressures were significantly higher both in primary aldosteronism and in EH patients compared with normotensives (P < .01). Impaired response to tilt was found in the heart rate and blood pressure variability in primary aldosteronism and EH patients; the increase in low frequency was smaller than in normotensives. Baroreflex gain (assessed by alpha index) was less in primary aldosteronism and EH patients as compared with normotensives. These findings may suggest that volume expansion or sympathetically mediated central translocation of the blood volume, or both, could stimulate the cardiopulmonary receptors and impair the baroreflex gain. Our findings suggest that an enhanced peripheral vascular responsiveness to a normal sympathetic outflow may be involved in the pathogenesis of hypertension in primary aldosteronism.

Baroreflex↗
PubMed1995

Assessment of renal resistance index after captopril test by Doppler in essential and renovascular hypertension.

Ultrasonic duplex scanning has been validated as a noninvasive method to evaluate the kidney arteries and hemodynamic characteristics of renal blood flow in patients with renal artery stenosis. The purpose of our study was to assess the changes in renal vascular impedance in 22 patients with renovascular hypertension, as compared with 45 essential hypertensives and 15 normotensives, by using the Doppler parameter resistance index (RI) before and after a captopril oral test. After the captopril test the delta RI decreased significantly in the stenotic artery (P < 0.05). Univariate analysis showed that PRA values after captopril correlated inversely with the changes of RI only in the stenotic artery (P < 0.05). Thus, our findings suggest that the application of the captopril test to renal echo-Doppler may represent a feasible, noninvasive, and inexpensively useful tool in the screening studies aimed at diagnosing renovascular hypertension.

Administration, Oral↗
PubMed1995

Role of alcoholic beverages in essential hypertensive patients.

To evaluate the importance of alcohol and other environmental factors in essential hypertensives, we conducted a cross-sectional study on 627 patients (322 women, 305 men) subdivided in four subgroups according to sex and presence or absence of drug therapy, to evaluate differences due to drugs and changes in life style. Multiple regression analyses were run where systolic and diastolic blood pressures were considered as separate dependent variables with the following independent variables: age, body mass index, physical activity, alcohol and coffee consumption, smoking, educational level; considered as continuous or categorical variables. eighty-eight per cent of all patients showed a moderate-low alcohol intake (1-50 g/day); wine was the preferred beverage. We found a negative independent relationship between mild/moderate alcohol consumption levels and systolic blood pressure in untreated men and untreated women, and no relationship between alcohol and diastolic blood pressure in all subgroups considered. Body mass index and age were positively associated with both systolic and diastolic blood pressure. Our data suggest that mild to moderate alcohol consumption does not affect blood pressure control in either treated or untreated hypertensive patients.

Age Factors↗
PubMed1994

Cardiovascular risk factors in adolescence: prevalence and familial aggregation.

BACKGROUND: In the field of primary prevention there is an increasing interest in screening pediatric populations for cardiovascular risk factors. The aim of this study was to determine the overall prevalence of high blood pressure (HBP), obesity, and sedentariness in a population of adolescents. The presence of familial aggregation for these factors was also evaluated. METHODS: The prevalence of HBP, obesity, and low physical activity was determined in 1413 adolescents ages 12-15 years (705 males, 698 females) randomly selected from Turin school children. The prevalence of HBP and obesity in parents was determined. RESULTS: One risk factor was found in 40.9% of females (2.4% HBP, 8.6% obesity, and 29.9% sedentariness) and 39.6% of males (2.8% HBP, 16.4% obesity, and 20.4% sedentariness); the concomitance of two or three risk factors were present, respectively, in 9.9 and 2.7% of females and 10.9 and 1.1% of males with a strong association of obesity and HBP. A significant familial aggregation for obesity was found and no particular relationship was found for BP. CONCLUSION: The ability to identify children developing a single or multiple risk factors is an important contribution to the prevention of serious cardiovascular diseases in adulthood.

Adolescent↗
PubMed1994

Statistical evaluation of circadian blood pressure rhythm during isradipine long-term therapy.

In this study, using the two-step truncated Fourier series with four harmonics, we analysed the diurnal blood pressure profile in 13 mild-moderate essential hypertensive patients during isradipine long-term therapy. Circadian parameters such as the amplitudes and phases of the four harmonics and the overall amplitude and phase were obtained from the model. The total duration of the study was 26 weeks. Ambulatory blood pressure was measured at 15-min, intervals using a Takeda TM 2420 device after 2 weeks of placebo and after 6 and 26 weeks of isradipine (5 mg daily) respectively. After 6 and 26 weeks therapy the blood pressure values showed a significant decrease, although the daily blood pressure curves obtained from Fourier analysis showed that the circadian rhythm was not altered by isradipine treatment. Both the night/day differences and the overall amplitude/acrophases were statistically significant at 0.6 and 26 weeks. According the nocturnal blood pressure fall, we found that long-term therapy with isradipine increased the number of patients with nocturnal blood pressure fall and reducing the early morning blood pressure rise. In conclusion, the two-step method Fourier analysis represents a novel and useful statistical approach to evaluate the presence of a significant diurnal blood pressure rhythm and to provide the circadian parameters of the 24-h blood pressure profile during pharmacological therapy.

Blood Pressure↗
PubMed1994

Plasma immunoreactive endothelin-1 in primary hyperaldosteronism.

This study evaluated the assessment of plasma endothelin-1 (ET-1) levels in primary aldosteronism and its correlation with other vasoactive hormones such as renin, aldosterone, catecholamines, arginine-vasopressin, and atrial natriuretic peptide. Plasma ET-1 was measured in 12 patients with primary aldosteronism (five adenomas and seven primary hyperplasia) and in 15 normal subjects. No significant differences were found in plasma ET-1 between controls and hypertensive patients both in adenoma and primary adrenal hyperplasia (8.8 + 1.6 pg/mL v 6.2 + 1.4 pg/mL v 6.5 + 1.0 pg/mL, P = NS, respectively). Further, no significant correlations were found among ET-1 and vasoactive hormones. In conclusion, these findings show that there are no differences in ET-1 levels between primary aldosteronism patients and healthy subjects. Circulating ET-1 is not involved in the hypertension in primary aldosteronism.

Adenoma↗
PubMed1994

Analysis of 24-h blood pressure profile by Fourier series during lacidipine therapy.

In the present study, we examined the circadian profile of blood pressure (BP) in 10 patients with moderate essential hypertension before and after 6 months of lacidipine therapy. Ambulatory BP was measured at 30-min intervals using SpaceLabs 90207. To account for the unequal time intervals between successive readings, BP means and variances were weighted for the time span between successive readings, and weighted linear-regression analysis was applied. The 24-h BP values were carried out using Fourier analysis, comparing the values from the baseline with those after 24 weeks of lacidipine. After 24 weeks BP values showed a significant decreased compared with baseline values (all p < 0.01). The daily BP curves obtained from Fourier analysis with four harmonics showed that the significant circadian rhythm in nine patients was not altered by lacidipine treatment. The night/day differences were statistically significant at 24 weeks vs. 0 week (all p < 0.01). The overall amplitude and acrophase of the BP curve were statistically significant at 24 weeks (all p < 0.01). After 24 weeks of lacidipine therapy, according to the nocturnal BP fall, we found three intermediate dippers, six dippers, and one non-dipper. By use of the two-step Fourier analysis method, which provides a formal and statistical method to evaluate the presence of a significant diurnal BP rhythm and parametrization of the 24-h BP recordings, we showed that lacidipine long-term therapy is effective in lowering BP and preserving the diurnal BP rhythm.

Antihypertensive Agents↗
PubMed1993

Twenty-four-hour power spectral analysis by maximum entropy method of blood pressure in primary hyperaldosteronism.

In the present study we estimated the periodic profiles and variance structure of systolic blood pressure, diastolic blood pressure, heart rate and mean arterial pressure by using an autoregressive model of power spectrum, Maximum Entropy Method (MEM) in 8 patients with primary aldosteronism, during long-term therapy with nicardipine slow release. The four blood pressure variables were measured at 30-min intervals, using a noninvasive device (Spacelabs 90202) in 8 hypertensive patients of whom 6 with idiopathic aldosteronism (IHA) and 2 with dexamethasone-suppressible aldosteronism (DSH), before and after 24 weeks of 80 mg nicardipine daily. Blood pressure data were processed by MEM and spectral profiles were obtained. During nicardipine therapy all patients showed a significant decrease of 24-h ambulatory blood pressure values (p < 0.01). Before therapy, spectrum analysis by MEM indicated the presence of high frequency distribution of peaks for SBP, DBP, MAP and HR. The MEM power spectrum showed an increase in amplitude of sharp peaks of systolic, diastolic, MAP and heart rate in all patients after therapy at 24 h corresponding to the circadian rhythm blood pressure. Furthermore, the trend of these variables synchronized themselves in the same period after 24 weeks of nicardipine therapy, with spectral patterns of blood pressure similar to those of normotensive subjects. This chronobiologic approach, by Maximum Entropy Method, may be used as an alternative statistical analysis to search for possible rhythmic behavior of ambulatory blood pressure data before and after pharmacological treatment in secondary hypertensive patients.

Activity Cycles↗
PubMed1992

Plasma endothelin levels in cirrhotic subjects.

Endothelin-1, a potent vasoconstrictor peptide with 21 amino acid residues, is released by the vascular endothelium. Plasma immunoreactive endothelin levels were measured in 23 patients with cirrhosis and in 20 healthy subjects. Concentrations were significantly lower in patients with non-uraemic cirrhosis than in normal subjects (19.4 +/- 8.9 pmol/l vs. 48.8 +/- 24.8 pmol/l, p less than 0.002). Plasma renin, aldosterone, atrial natriuretic peptide, arginine-vasopressin and catecholamines did not show significant correlations with plasma endothelin-1 levels. Furthermore, there were no significant differences in plasma endothelin levels for etiology of cirrhosis, presence of ascites or varices. These data suggest that low circulating endothelin may be involved in the development or maintenance of systemic vasodilatation in cirrhosis.

Adult↗
PubMed1992

Renal resistive index after captopril test by echo-Doppler in essential hypertension.

In 45 patients with essential hypertension and 15 age-matched normotensive control subjects, the renal resistive index, as an expression of arterial impedance, was determined using Doppler ultrasound. In both kidneys the resistive index was assessed at baseline and after captopril test (50 mg orally). In the moderate and severe hypertensives, compared to mild hypertensives and control subjects, the baseline resistive index was significantly higher (P less than .05). Following captopril, the resistive index increased only in normotensives (P less than .05) and in mild hypertensives (P less than .05). Univariate and multivariate analyses show that the duration and severity of hypertension correlated with an increase of the resistive index both in basal and in dynamic conditions. Thus, the use of the resistive index, as determined by echo-Doppler, could provide useful information for the assessment of renal vascular impedance in essential hypertensive patients. This would help us detect the evolution of hypertensive disease to the higher degrees of severity that are correlated to renal arteriolar damage.

Adult↗
PubMed1992

Hormonal aspects of the relation of liver cirrhosis to essential hypertension.

The association of liver cirrhosis with arterial essential hypertension has been previously described. The present study extends the previous reports by investigating the hormonal relationships that may occur in patients with established essential hypertension associated to liver cirrhosis. We studied the renin-angiotensin, the adrenergic systems and other vasoactive hormones such as arginine-vasopressin, atrial natriuretic peptide, endothelin and parathyroid hormone in cirrhotic patients with and without essential hypertension. The data suggested that the coincidence of arterial hypertension in cirrhotic patients was characterized by the following findings: a decreased renin-angiotensin activity; a reduced systemic vasodilatation; an increased peripheral pressor effect of vasoactive hormones and an increased effective blood volume.

Adult↗
PubMed1991

[The calcium salt of folinic acid for the treatment of deficiency anemia].

Thirty patients (20 adults and 10 children) suffering from nutritional anaemias were treated with folinic acid for 15 days per os at a dosage of 4-8 mg daily. For each patient routine laboratory tests, folic acid assays in the serum and in the erythrocytes have carried out and the clinical parameters have been recorded at the beginning and at the end of the treatment. The results showed statistically significant increase in the number of red cells per cmm, in folic acid content both in the serum and in the erythrocytes; at the same time a decrease of mean corpuscular haemoglobin concentration (MCHC) and mean corpuscular haemoglobin (MCH) was observed.

Adult↗
PubMed1990

[Liver and thyroid gland. Physiopathologic and clinical relationships].

The liver plays a dominant role in the metabolism of the thyroidal hormones; it is here that the 5' deiodase acts to convert part of T4 to T3. There are eight further circulating iodothyronines: the rT3, mainly derived from T4, appears to be the major inhibitor of T4 and T3. Thus, if rT3 increases, the metabolic effects of T3 and T4 can be quite different. In the course of some chronic systemic diseases (e.g. hepatic cirrhosis) rT3 increases simultaneously with the decrease of T3 levels. Therefore we can describe particular alterations of the thyroidal pattern typical of chronic liver diseases: low T3 syndrome, low T3 and T4 syndrome, high T4 syndrome, mixed forms. T3 and T4 diminish due to inefficient hepatic deiodination and defective hepatocellular uptake. Inefficient hepatic deiodination and defective hepatocellular uptake. T4 levels decrease, most likely because of an inefficient production of thyroid binding globulin, or the action of a peripheral binding inhibitor. During acute liver diseases and primitive biliary cirrhosis, we can observe an increase of T4 and TBG together with an increase of the acute phase proteins. Such complex hormonal mechanisms are not influenced by TSH, which appears normal or inhibited, as the TRH stimulus test is normal. The explication can be found in an enhanced conversion of T4 to T3 in the pituitary gland. The biological and clinical significance of these mechanisms might be that of creating a "protective" state for an organism in a catabolic state by reducing the circulating T3. A relationship has been found between circulating thyroidal hormones levels, particularly the T3, rT3 and rT3/T3 ratio, and the state of hepatic functional insufficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Homeostasis↗
PubMed1990

Efficacy of nicardipine slow release (SR) on hypertension, potassium balance and plasma aldosterone in idiopathic aldosteronism.

We evaluated the efficacy and tolerance of a dihydropyridine calcium antagonist, nicardipine slow release, in eight patients with idiopathic aldosternism. Nicardipine (80 mg/day) was given orally for 12 weeks and no dietary restrictions were imposed. During the study measurements were made of supine blood pressure, plasma renin activity, plasma aldosterone concentration, and serum potassium. Nicardipine lowered systolic and diastolic blood pressure to normal, plasma aldosterone was reduced and serum potassium levels were increased. Basal renin concentration was not altered by nicardipine. There were no side effects sufficient to cause withdrawal from the study. These results suggest that nicardipine, for efficacy and tolerance, may represent an alternative among Ca2+ channel blockers, either controlling blood pressure or reducing aldosterone levels in patients with idiopathic aldosteronism.

Administration, Oral↗