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Biomedical subjects

A Rappelli

Publications and source records attributed to A Rappelli.

At least 37 records · Page 2Linked to original sources
PubMed1995

Angiotensin converting enzyme gene polymorphism and carotid atherosclerosis in a low-risk population.

OBJECTIVES: Angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism has been shown to be an independent risk factor for myocardial infarction and other cardiovascular diseases. The aim of the study was to investigate the relationship between ACE genotype and carotid atherosclerosis evaluated by ultrasonography. PATIENTS AND METHODS: ACE I/D polymorphism was determined in 240 low-risk patients (mean age 53.6 +/- 7 years) in relation to traditional risk factors and the degree of carotid atherosclerosis. Intimal-medial thickness was measured at the level of the common carotid artery, bifurcation and internal carotid on both sides. Patients were defined as normal (n = 47, intimal-medial thickness <1.0 mm), thickened (n = 56, intimal-medial thickness > or = 1.0 and < or = 1.3 mm in the thickest wall) or with an atherosclerotic plaque (n = 137, intimal-medial thickness >1.3 mm for at least one level of examination). Age, sex, body mass index, blood pressure levels and prevalence of other risk factors were similar in the three groups. I/D polymorphism was determined by polymerase chain reaction using specific primers and genomic DNA from leukocytes as template. Plasma ACE levels, plasma renin activity and plasma aldosterone were evaluated in all patients by standard procedures. RESULTS: No significant differences were found in humoral parameters, ACE, genotype distribution and the corresponding allele frequency among the three groups of patients. Only ACE plasma levels were significantly higher in the DD and ID genotypes compared with the II genotype (DD 14.27 +/- 5.05 IU/ml, ID 12.70 +/- 4.31 IU/ml; II 8.04 +/- 3.45 IU/ml). The mean intimal-medial thickness was similar in all three genotypes. CONCLUSION: Although ACE genotype has been shown to be related to coronary atherosclerosis, the present data do not indicate that the DD genotype is associated with carotid atherosclerosis. However, further studies of larger populations are needed to clarify whether genetic ACE polymorphism is associated with carotid atherosclerosis.

Arteriosclerosis↗
PubMed1994

Differentiation and growth of vascular smooth muscle cells in experimental hypertension.

In this review we have analyzed the present knowledge about the differentiation and growth processes in vascular smooth muscle cells (SMC) in hypertension. The study of smooth muscle (SM) and nonmuscle (NM) myosin isoform expression has permitted us to identify a three-stage specific maturational pathway, namely, fetal, postnatal, and adult. In the renovascular (rabbit) and genetic (rat) models of hypertension, adaptive changes occurring in hypertensive vessels make SMC resemble those found in the early stages of development (smooth muscle plasticity). In fact, based on SM- and NM-myosin isoform distribution, postnatal-type SMC predominate in the arterial media during the early remodeling of the arterial wall that occurs in hypertension, whereas postnatal- and fetal-type SMC predominate in the intimal thickening. Locally produced or activated autocrine/paracrine factors, such as growth factors or cytokines, along with circulating hormones, seem to be involved in the growth response or changes in the differentiation pattern of SMC. Thus, these factors not only play a specific role in the regulation of blood pressure, but also are likely to be responsible for the remodeling of the arterial wall in hypertension.

Animals↗
PubMed1994

Hyperplastic growth of aortic smooth muscle cells in renovascular hypertensive rabbits is characterized by the expansion of an immature cell phenotype.

Smooth muscle cells (SMCs) of rabbit aorta undergo marked changes in myosin isoform content during development. Analysis of nonmuscle myosin composition at the protein level has permitted the identification of three phases in the SMC differentiation process: fetal, postnatal, and adult. Using monoclonal antibodies specific for smooth muscle and nonmuscle myosins and extra domain A of fibronectin as well as cDNA probes for platelet-derived growth factors (PDGF) and various procollagens, we have evaluated the differentiation pattern of aortic SMCs in two-kidney, one-clip hypertensive rabbits. Morphometric and bromo-deoxyuridine studies indicate that hypertrophy of aortic media along with intimal thickening occurring in hypertensive animals is due to SMC hyperplasia. Western blotting experiments performed on aortic specimens from hypertensive animals with antimyosin antibodies revealed the appearance of a myosin isoform pattern of the "immature" type. Immunofluorescence tests showed that these cells are localized in the thickened intima or distributed in the underlying media (sparsely or in groups). Similarly, the fibronectin variant showing the extra domain A, peculiar to "phenotypically modulated" SMCs, appeared in intimal thickening, and its expression followed the time course of nonmuscle myosin expression. Counting of postnatal-type SMCs in the aortic media revealed that this cell population increases markedly with hypertension (2- up to 15-fold at 4 months) and then declines to near control level in 8-month hypertensive rabbits. Diminution of postnatal-type SMCs at later stages of hypertension was temporally correlated with the slowing down of aortic wall hypertrophy. Average levels of mRNAs, as determined by densitometric analysis in aortas from 1- and 2.5-month hypertensive rabbits, showed an increased expression for PDGF beta receptor (up to twofold), procollagen type I (alpha 1, threefold), procollagen type III (alpha 1, twofold), and fibronectin (up to threefold) compared with controls. Conversely, the steady-state levels of mRNAs for PDGF (A and B chain), PDGF alpha receptor, TGF-beta 1, and procollagen type IV (alpha 1) did not increase significantly. These results provide evidence that in adult renovascular hypertensive rabbits, the hyperplastic growth of aortic SMCs is accompanied by the expansion of an "immature" cell phenotype characteristic of the early stages of development.

Actins↗
PubMed1994

[The role of ACE inhibitors in heart failure. Lessons of CONSENSUS, SOLVD and V-HeFTII].

Heart failure is today one of the most serious health problems of modern industrialized societies. The increase in the mean age of the population is an additional factor which favours a high incidence of episodes of heart failure. Age is also a relevant factor in mortality linked with heart failure. On this basis more emphasis has been given by researchers and physicians to improve a preventive and therapeutic approach to heart failure. For many years the pharmacological treatment of heart failure patients was based on the increase in inotropism through the digitalis and on the reduction in sodium-water retention through diuretics, while less importance was given to the improvement of the afterload. We have had knowledge of vasodilatory drugs in chronic heart failure for at least 20 years but only 10 years ago with the Vasodilator-Heart Failure Trial (V-HeFTI), it was proved that the combination of hydralazine and nitrates in addition to the conventional treatment, improved the survival of patients affected by moderate-severe heart failure. With the advent of the ACE-inhibitors, in the '80s, the first studies concerning the role of such drugs in heart failure were carried out. In the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS I) it was proved for the first time that an ACE-inhibitor (enalapril), added to the conventional heart failure therapy, improved the survival of patients with severe congestive heart failure (NYHA class IV). The result was so extraordinary that the study was interrupted for ethical reasons. However, it has raised a considerable interest in the study of the ACE-inhibitors in heart failure and now it has been proved that such drugs are a milestone in a correct pharmacological approach to heart failure.

Adult↗
PubMed1993

Ischemia in collateral-dependent myocardium: effects of nifedipine and diltiazem in man.

It has recently been shown that ischemia in collateral-dependent myocardium may develop at a very variable threshold in anginal patients; accordingly, the aim of this study was to assess whether nifedipine and diltiazem can increase blood flow to collateralized myocardium in man. Nine patients with complete coronary occlusion filled by collaterals, with no other coronary stenosis, normal left ventricular function, and reproducibly positive exercise tests were studied. They underwent exercise tests off therapy and after acute randomized administration of nifedipine (10 mg sublingually), diltiazem (120 mg orally), and nitroglycerin (0.5 mg sublingually), the latter a drug known to increase blood flow to collateralized myocardium. Following nifedipine, time to 1 mm ST segment depression increased significantly (from 430 +/- 176 to 576 +/- 205 seconds, p < 0.01), while heart rate and rate-pressure product remained unchanged (115 +/- 16 vs 121 +/- 17 beats/min and 199 +/- 29 vs 204 +/- 44 beats/min.mm Hg.10(2), respectively, p = NS for both). Similarly, diltiazem significantly increased time to ischemic threshold from baseline to 638 +/- 125 seconds (p < 0.01), but did not change heart rate and rate-pressure product at 1 mm ST segment depression. Submaximal rate-pressure products were significantly lowered by both nifedipine and diltiazem. Nitroglycerin not only significantly improved time to ischemic threshold (from baseline to 666 +/- 76 seconds, p < 0.01), but also increased heart rate (from baseline to 137 +/- 16 beats/min, p < 0.01) and rate-pressure product (from baseline to 242 +/- 48 beats/min.mm Hg.10(2), p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Are there differences in the renal effects of calcium antagonists?

AIM: To review the effects of calcium antagonists, and of the new dihydropyridine lacidipine in particular, on the glomerular filtration rate, renal plasma flow, and the sodium to water ratio in hypertensive patients. METHODS: Review of published data. RESULTS: Different studies have shown a wide range of responses to all three subgroups of calcium antagonists in glomerular filtration rates and in renal plasma flows. In some studies there was a reduction and in others a rise in these two renal parameters. The administration of lacidipine was associated with a significant rise in renal plasma flow which disappeared with chronic treatment and no change in the glomerular filtration rate. There are only a few studies on the long-term natriuretic and diuretic effects of calcium antagonists. In the short term, dihydropyridine calcium antagonists appear to produce diuretic and natriuretic effects, but these effects are not seen with verapamil. Lacidipine showed no trend towards sodium and water retention. CONCLUSIONS: Reported differences between calcium antagonists in glomerular filtration and renal plasma flow probably reflect differences in the baseline tone of pre- and postglomerular arterioles. Calcium antagonists do not cause sodium and water retention during chronic therapy. The new dihydropyridine derivative lacidipine lowers blood pressure without reducing renal function or causing sodium and water retention.

Antihypertensive Agents↗
PubMed1993

Urinary kallikrein excretion and blood pressure response to angiotensin converting enzyme inhibitors and calcium antagonists in hypertensive patients.

OBJECTIVE: To investigate whether the hypotensive effects of angiotensin converting enzyme (ACE) inhibitors in comparison with those of calcium antagonist might be predicted by urinary kallikrein activity, a marker of the activity of the renal kallikrein-kinin system. DESIGN: Seventy-five essential hypertensive patients were randomly assigned to treatment with ACE inhibitors (enalapril or lisinopril 20 mg once a day) or with calcium antagonists (nifedipine 20 mg twice a day or lacidipine 4 mg once a day). Fifty-four had normal (NK) and 21 low (LK) kallikrein activity. Blood pressure was measured after 2 weeks, and 3 and 6 months. Patients whose diagnostic blood pressure, 2 weeks after the first dose, decreased by at least 15 mmHg or was < or = 90 mmHg were defined as responders. The others were defined as non-responders. In non-responders a second drug was added and the patients were not considered for further analysis. METHODS: Urinary kallikrein activity was determined by a spectrophotometric assay using a synthetic chromogenic substrate. RESULTS: After 2 weeks therapy with ACE inhibitors 88% of NK patients were responders, whereas in the LK subgroup 40% were responders, a significant difference between subgroups. For the patients treated with calcium antagonists, conversely, 59% of NK patients were responders in comparison with 82% of the LK subgroup, a significant difference between drug groups. After 3 and 6 months of treatment blood pressure was significantly lower in NK patients treated with ACE inhibitors and in LK patients treated with calcium antagonists. In the NK group on ACE inhibitors the mean arterial pressure after the first dose was significantly related to that observed after 6 months (n = 0.71, P < 0.01). CONCLUSIONS: Our data indicate that urinary kallikrein activity may represent an index to predict the chronic antihypertensive effect not only of ACE inhibition but also of calcium antagonism, and support the concept that the renal kallikrein-kinin system might play some contributory role in modulating the hypotensive action of ACE inhibitors.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

A renin-secreting tumour with severe hypertension and cardiovascular disease: a diagnostic and therapeutic challenge.

A case of renin-secreting juxtaglomerular cell tumour which presented with a severe hypertensive crisis and did not respond to angiotensin converting enzyme inhibitors but was promptly controlled by intravenous labetalol is reported. The diagnostic difficulties which can be encountered in such cases and the usefulness of the different diagnostic tests, including renal vein renin measurement, are discussed.

Adult↗
PubMed1993

[Rational criteria for the choice of ACE inhibitor adapted to the individual hypertensive patient].

Attempts to rationalise the treatment of hypertension on the basis of pathophysiological and clinical characteristics of patients, such as renin profile and age, have had minimal success in the past. More recently it has been found that the response to ACE inhibitors or calcium antagonists might be predicted on the basis of the ability of the kidney to produce kallikrein. Urinary excretion of active kallikrein is considered an index of the activity of the renal-kallikrein system and this system is thought to play an important role in modulating the effects of ACE inhibitors. In patients with low urinary kallikrein excretion the efficacy of ACE inhibitors is blunted and, on the contrary, that of calcium antagonists seems to be enhanced. Among ACE inhibitors the choice of a specific drug might also-based upon the effects of the molecule on the tissue renin-angiotensin system. In this regard lipophilic ACE inhibitors, such as ramipril, may produce a therapeutic effect at doses which are better tolerated due to greater tissue penetration.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

A novel endothelial tyrosine kinase cDNA homologous to platelet-derived growth factor receptor cDNA.

Degenerate oligonucleotide primers complementary to the highly conserved subdomains III and VIII of subclass III tyrosine kinase receptors (TKr-III) were utilized to amplify rat aortic cDNA by polymerase chain reaction. Most of the cloned DNA products were rat platelet-derived growth factor receptor beta and macrophage-colony stimulating growth factor receptor cDNAs. Screening of the clones with probes coding for the receptor-specific kinase insert domain allowed the identification of a novel putative TKr-III cDNA, which hybridized with a approximately 6.1 kb mRNA with a distinctive tissue distribution. In situ hybridization on rat tissues and Northern analysis of cultured cells indicate that endothelial cells express a novel putative TKr-III mRNA.

Amino Acid Sequence↗
PubMed1992

High levels of plasma atrial natriuretic factor and impaired left ventricular diastolic function in hypertensives without left ventricular hypertrophy.

OBJECTIVE: To seek possible correlations between plasma atrial natriuretic factor (ANF) and left ventricular diastolic function (LVDF) in hypertensive patients. DESIGN: Since LVDF abnormalities can be detected in patients with normal left ventricular mass, we studied a group of hypertensive patients without left ventricular hypertrophy. METHODS: Untreated hypertensive patients (n = 23) and normotensive control subjects (n = 19) were studied. LVDF indices were obtained by M-mode and pulsed Doppler echocardiography. Blood samples for plasma ANF were taken in the recumbent position from subjects on normal-sodium intake. RESULTS: Plasma ANF levels were significantly higher in hypertensive patients than in normotensive subjects. All indices for systolic function were normal in both normotensive subjects and hypertensive patients. Left atrial diameter was significantly higher for hypertensive patients than for normotensive subjects. Considering LVDF, all indices for ventricular filling were found to be altered, on average, in hypertensive patients, the only exception being peak early velocity. In addition, significant correlations were found between plasma ANF and the pulsed Doppler parameters of left ventricular filling, peak atrial velocity and the peak early:peak atrial velocity ratio. Overall correlations between plasma ANF and left atrial diameter, and between left atrial diameter and left ventricular mass index were also observed. CONCLUSIONS: The high levels of plasma ANF observed in our hypertensive patients and their correlation with the LVDF indices (which mainly reflect the atrial contribution to ventricular filling) could be the result of an increased atrial stretch due to diastolic ventricular dysfunction. This may exist in hypertensive patients before the development of ventricular hypertrophy.

Adult↗
PubMed1992

Local renin-angiotensin system in human adrenals and aldosteronomas.

The local renin-angiotensin system may regulate adrenal cell growth and function. Angiotensinogen, renin, and angiotensin converting enzyme gene expression were studied in four normal adrenal glands (removed from patients with renal carcinomas) and five aldosterone-secreting adenomas. Northern blot analysis showed expression of angiotensinogen messenger RNA (mRNA) in normal adrenals at levels approximately 35-fold lower than liver and sixfold lower than kidney. Similar angiotensinogen mRNA levels were present in two aldosteronomas, whereas a third had levels approximately 50% of those found in kidney. Renin mRNA was detectable in most normal adrenals and in three adenomas, one of which had relatively high renin mRNA levels. Angiotensin converting enzyme gene was expressed in adrenal tissue and in three adenomas. Portions from these normal adrenals and two of these aldosteronomas, as well as samples from two other adrenals and three aldosteronomas, were also studied in an in vitro superfusion system coupled with active renin radioimmunometric assay, angiotensin II/III, and aldosterone radioimmunoassay. Total amounts of active renin and angiotensin II/III released from normal adrenals during 270 minutes of superfusion were higher than the amounts released from aldosteronomas (312 +/- 35 versus 187 +/- 43 and 823 +/- 100 versus 436 +/- 55 pg/100 mg tissue, respectively; mean +/- SEM, p less than 0.05), whereas aldosterone release from the adenomatous tissue was approximately threefold higher (320 +/- 21 versus 115 +/- 18 ng/100 mg tissue; mean +/- SEM, p less than 0.01). Total amounts of active renin and angiotensin II/III released by normal or adenomatous adrenal samples exceeded threefold to fourfold the amounts extracted from similar samples of the same surgical specimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Neoplasms↗
PubMed1992

[Long-term treatment of stable angina pectoris with gallopamil].

BACKGROUND: The effects of long-term treatment with gallopamil 50 mg t.i.d were assessed in 8 patients, 7 males and 1 female, aged 47-69 years, with stable angina pectoris, positive exercise tests, coronary artery disease and no previous myocardial infarction. METHODS: Clinical and ECG parameters as well as exercise testing, 24-hour Holter and echocardiography were assessed before treatment, after 3 months, after 1 and 2 years of treatment, and following final wash-out. RESULTS: Comparing each treatment period to baseline, a significant decrease in resting heart rate (from 66 +/- 9 beats/min at baseline to 56 +/- 7 beats/min after 3 months [p < 0.01], 59 +/- 8 beats/min after 1 year [p < 0.05] and 58 +/- 9 beats/min after 2 years [p < 0.05]), systolic (from 162 +/- 19 mmHg at baseline to 147 +/- 12 mmHg after 3 months [p < 0.05], 146 +/- 20 mmHg after 1 year [p < 0.01] and 146 +/- 27 mmHg after 2 years [p < 0.05]), and diastolic (from 89 +/- 6 mmHg to 82 +/- 7 after 3 months [p < 0.05], 82 +/- 4 after 1 year [p < 0.05] and 83 +/- 4 after 2 years [p < 0.05]) blood pressure was observed. Exercise time significantly improved (from 596 +/- 209 seconds to 802 +/- 66 seconds after 3 months [p < 0.01], 710 +/- 167 seconds after 1 year [p < 0.05] and 723 +/- 125 seconds after 2 year [p < 0.05]), while heart rate and rate-pressure product at peak exercise did not change. The number of ischemic episodes and the total ischemic time per 24 hours significantly decreased (from 35 +/- 15 min to 12 +/- 10 min after 3 months [p < 0.05], 10 +/- 8 min after 1 year [p < 0.05] and 11 +/- 9 min after 2 years [p < 0.05]). Ejection fraction increased (from 66 +/- 10% to 77 +/- 7% after 3 months [p < 0.01], 80 +/- 5% after 1 year [p < 0.01] and 80 +/- 3% after 2 years [p < 0.01]), while contractility, as expressed by the end-systolic stress/end systolic volume ratio remained unchanged. No serious side-effects or biochemical abnormalities developed. CONCLUSIONS: Gallopamil appears to be safe, well tolerated and effective in the long term control of angina pectoris; its effects are fully developed at 3 months and persist unchanged after 2 years. For its hypotensive action and the lack of significant effects on myocardial contractility, gallopamil appears to be potentially useful in patients with associated angina and hypertension and in patients with impaired left ventricular function.

Aged↗
PubMed1991

Relationship between plasma atrial natriuretic factor and urinary kallikrein excretion in essential hypertensives.

In order to seek possible relationships between renal kallikrein and atrial natriuretic factor (ANF), we measured urinary kallikrein (UK) and ANF in 84 normal subjects (NS) and in 104 uncomplicated essential hypertensives (HP). Atrial natriuretic factor was significantly higher in HP than in NS (38.5 +/- 1.3 vs 29.0 +/- 1.3 pg/mL, P less than .01), whereas UK was significantly lower in HP than in NS (11.1 +/- 0.9 v 15.3 +/- 0.6 nkatal/24 h, P less than .01). Calculating the 95% of the percentile distribution of the single values of UK in the group of NS we were able to show that 24 out of 104 HP had a UK which fell below the lowest limit (4.5 nkat/24 h) of the normal range. We therefore divided our HP into two subgroups: patients with normal kallikrein excretion (NK) (n = 80; mean UK 13.8 +/- 0.8 nkat/24 h) and patients with low kallikrein excretion (LK) (n = 24; mean UK 2.3 +/- 0.3 nkat/24 h). Normal kallikrein patients had a mean plasma ANF value of 31.9 +/- 1.2 pg/mL which was almost superimposable to that found in NS; on the contrary, the mean plasma level of ANF in LK patients (50.7 +/- 2.2 pg/mL) was significantly higher than that measured in NK patients and in NS (P less than .01 v NK patients and NS, respectively). Since a low urinary kallikrein excretion may represent a marker of an impaired production of renal kallikrein, the high levels of ANF found in the LK subgroup could be the result of a compensatory response of the atrium attempting to maintain sodium and volume homeostasis.

Atrial Natriuretic Factor↗
PubMed1991

Controlling hypertension: lisinopril-hydrochlorothiazide vs captopril-hydrochlorothiazide. An Italian multicentre study.

The efficacy and tolerability of a combination of lisinopril 20 mg and hydrochlorothiazide 12.5 mg once daily (L/HCTZ) was compared with a combination of captopril 50 mg and hydrochlorothiazide 25 mg once daily (C/HCTZ) in a multicentre, open, randomized, parallel-group study involving mild to moderate hypertensive patients. A total of 87 patients were randomized to lisinopril and 87 to captopril. Six weeks of treatment with lisinopril or captopril lowered supine BP by 13.3/8.8 mm Hg and 8.7/6.5 mm Hg, respectively. After 4 weeks of combination treatment, BP 24 hours post dose fell to 144.0 +/- 1.3/88.1 +/- 0.7 mm Hg in the L/HCTZ group vs 146.8 +/- 1.3/90.3 +/- 0.7 mm Hg in the C/HCTZ group (P less than 0.05 DBP; differences in SBP were not significant, ns). The proportion of patients normalized (DBP less than or equal to 90 mm Hg) was 79.5% vs 72% for L/HCTZ and C/HCTZ, respectively (ns). A total of 93.6% of patients on L/HCTZ achieved a fall in DBP of greater than or equal to 10 mm Hg, compared with 86.7% of patients on C/HCTZ (ns). One patient on lisinopril withdrew because of coughing. No statistically significant differences were observed between L/HCTZ and C/HCTZ with regard to adverse events. In conclusion, L/HCTZ was as well tolerated as C/HCTZ, but produced a greater fall in DBP.

Adolescent↗
PubMed1991

The effects of antihypertensive therapy on renal function.

Renal vascular resistance is increased in essential hypertension, with a consequent reduction in renal plasma flow together with a normal or slightly reduced glomerular filtration rate. Non-specific vasodilators may exacerbate this effect while loop diuretics, beta-blockers, angiotensin converting enzyme inhibitors and calcium antagonists may increase these renal hemodynamic parameters. We studied the effect of lacidipine, a new long-lasting calcium antagonist, on renal hemodynamics in 11 essential hypertensives. Lacidipine (4 mg once a day) acutely increased renal plasma flow without affecting the glomerular filtration rate. A transient, but non-significant, diuresis and natriuresis occurred. After 4 weeks of lacidipine treatment, all the parameters of renal function returned to basal levels. These results suggest that the well known renal effects of calcium antagonists are, at least in part, related to the onset of the antihypertensive effect being more pronounced with compounds such as nifedipine which have a rapid-onset, blood pressure-lowering effect.

Adrenergic beta-Antagonists↗