Biomedical subjects

E Pavan

Publications and source records attributed to E Pavan.

16 recordsLinked to original sources

PubMed2007

Corn oil supplementation to steers grazing endophyte-free tall fescue. I. Effects on in vivo digestibility, performance, and carcass traits.

Eighteen Angus steers (438 +/- 4 kg of BW) were supplemented with varying levels of corn oil (0 g/kg of BW, none; 0.75 g/kg of BW, MED; or 1.5 g/kg of BW, HI) on rotationally stocked, endophyte-free tall fescue to determine the effect of supplemental oil level on in vivo digestibility, intake, performance, and carcass traits. Pelleted cottonseed hulls were used as a carrier for the oil supplements, and all supplements were offered to steers using Calan gate feeders for individual intake determination. On d 49, each steer was dosed with a controlled-release capsule containing chromium sesquioxide, and fecal samples were obtained 12 d later over a 7-d period to estimate fecal output that, with forage, supplement, and fecal indigestible NDF concentration, was used to estimate DMI and in vivo total diet digestibility. Steers were slaughtered at the end of the 116-d grazing period, and carcass data were collected at 24 h postmortem. Total fatty acid intake linearly increased with corn oil supplementation, and forage DMI, total DMI, and total DE intake were linearly decreased (P < 0.01). The decrease in total DMI was reflected in forage substitution rates greater (P < or = 0.01) than 1, with a trend (P = 0.09) for a greater substitution rate in HI than in MED. In vivo DM, OM, and NDF digestibility were linearly decreased (P < 0.01) by corn oil supplementation. Average daily gain and final BW tended (P = 0.09) to increase linearly in response to oil level. Oil conversion (0.36 kg of BW gain/kg of corn oil) was greater (P < or = 0.05) than zero and did not differ (P = 0.15) between MED and HI. Dressing percent (P = 0.09), carcass weight (P = 0.01), and carcass backfat thickness (P = 0.01) increased linearly with oil supplementation. No treatment effect was observed for carcass LM area, KPH percentage, marbling score, or yield grade (P > 0.10). Oil supplementation to grazing steers linearly reduced forage DMI intake; however, animal performance was maintained and tended to be greater for oil-supplemented cattle. Oil supplementation increased carcass fat thickness and weight without altering other carcass quality parameters.

Animal Feed↗

PubMed2004

Evaluation of an ambulatory system for gait analysis in hip osteoarthritis and after total hip replacement.

Spatial and temporal parameters of gait have clinical relevance in the assessment of motor pathologies, particularly in orthopaedics. A new gait analysis system is proposed which consists of (a) an ambulatory device (Physilog) including a set of miniature gyroscopes and a portable datalogger, and (b) an algorithm for gait analysis. The aim of this study was the validation of this system, for accuracy and clinical applicability. Eleven patients with coxarthrosis, eight patients with total hip arthroplasty and nine control subjects were studied using this portable system and also a reference motion analyzer and force plate. The small differences in the stance period (19 +/- ms), stride length and velocity (0.4 +/- 9.6 cm and 2.5 +/- 8.3 cm/s, respectively), as well as thigh and shank rotations (2.4 +/- 4.3 degrees and 0.3 +/- 3.3 degrees, respectively), confirmed good agreement of the proposed system with the reference system. In addition, nearly the same accuracy was obtained for all three groups. Gait analysis based on Physilog was also in agreement with their Harris Hip Scores (HHS): the subjects with lower scores had a greater limp, a slower walking speed and a shorter stride. This ambulatory gait analysis system provides an easy, reproducible and objective method of quantifying changes in gait after joint replacement surgery for coxarthrosis.

Aged↗

PubMed2000

EMG signals detection and processing for on-line control of functional electrical stimulation.

The surface EMG signal detected from voluntarily activated muscles can be used as a control signal for functional neuromuscular electrical stimulation. A proper positioning of the recording electrodes in relation to the stimulation electrodes, and a proper processing of the recorded signals is required to reduce the stimulus artefact and the non-voluntary contribution (M-wave). Six orientations and six locations of the recording electrodes were investigated in the present work. A comb filter (with and without a blanking windowing) was applied to remove the signal components synchronously correlated to the stimulus. An operative definition of the signal to noise ratio and an efficiency index were implemented. It resulted that when the recording electrodes were located within the two stimulation electrodes the best orientation was perpendicular to the longitudinal line. However the best absolute indexes were obtained when the recording electrodes were located externally of the stimulation electrodes, and in that case the best orientation was longitudinal. Concerning the filtering procedure, the use of a blanking window before the application of the comb filter, gave the best performance.

Artifacts↗

PubMed1999

Endothelin-1 and its mRNA in the wall layers of human arteries ex vivo.

BACKGROUND: The participation of endothelin-1 (ET-1) in the control of vascular tone in humans has been questioned, on the basis of the finding of subthreshold immunoreactive (ir) ET-1 plasma levels. However, because most ET-1 is secreted abluminally, it might attain a higher concentration in the tunica media than in plasma. Furthermore, evidence indicates that vascular smooth muscle cells (VSMCs) can synthesize ET-1 on stimulation in vitro. We therefore looked for irET-1 in the different layers of the wall of human arteries, including renal, gastric, and internal thoracic artery wall, obtained ex vivo from consenting patients with coronary artery disease and/or high blood pressure undergoing surgery, as well as from young organ donors. METHODS AND RESULTS: We performed immunohistochemistry with specific anti-ET-1 and anti-vWF antibodies followed by detection with an avidin-biotin complex ultrasensitive kit. The presence of preproET-1 and human endothelin-converting enzyme-1 (hECE-1) mRNA was also investigated by reverse transcription-polymerase chain reaction in homogenates of vessel wall, including preparations deprived of both endothelium and adventitia, and in isolated VSMCs. We detected irET-1 in the endothelium of all arteries and in the tunica media of internal thoracic artery from most patients with coronary artery disease. PreproET-1 and hECE-1 mRNA was also detected in VSMCs isolated from these vessels. irET-1 and irvWF staining in endothelium and tunica media was measured by use of microscope-coupled computer-assisted technology. Significant correlations between the amount of irET-1 in the tunica media and mean blood pressure (P<0.05), total serum cholesterol (P<0.05), and number of atherosclerotic sites (P<0.001) were found. Thus, in organ donors, irET-1 was detectable almost exclusively in endothelial cells, whereas in patients with coronary artery disease and/or arterial hypertension, sizable amounts of irET-1 were detectable in the tunica media of different types of arteries. In addition, VSMCs isolated from these vessels coexpressed the preproET-1 and hECE-1 genes. CONCLUSIONS: Collectively, these findings are consistent with the contention that endothelial damage occurs in most patients with atherosclerosis and/or hypertension and that ET-1 is synthesized in VSMCs of these patients.

Adult↗

PubMed1998

Screening for primary aldosteronism with a logistic multivariate discriminant analysis.

OBJECTIVE: Primary aldosteronism (PA) is the most common endocrine cause of curable hypertension, but no single test unequivocally identifies it. Accordingly, we investigated the usefulness of a logistic multivariate discriminant analysis (MDA) approach for PA screening. DESIGN: Generation of a logistic MDA function based on retrospective analysis of biochemical tests in a large cohort of referred patients with/without confirmed Conn's adenoma (CA), followed by prospective validation of the model. PATIENTS: We investigated 574 selected hypertensives: 206 (32 with and 174 without CA) retrospectively, 48 (with a 13% prevalence of CA) prospectively for the validation of the model, and 320 referred hypertensives (with a 3.4% prevalence of CA) similarly evaluated. Patients were referred to a specialised centre for hypertension (4th Clinica Medica--University of Padua) and to a department of Internal Medicine of a regional hospital (Reggio Emilia). MEASUREMENTS: In all patients we measured several demographic and biochemical variables and performed a captopril test. A stepwise analysis of variance, based on a model fitted with several different variables, identified baseline (sALDO) and captopril-suppressed plasma aldosterone (cALDO), supine plasma renin activity (sPRA) and K+ as the most informative. Therefore, two models of logistic MDA with sPRA, K+, and either sALDO (model A) or cALDO (model B) were developed and used. ROC analysis was also performed to assess the optimal cut-off values. RESULTS: The model B of MDA provided the best performance and identified CA with 100% sensitivity and 81% accuracy. When used prospectively it showed 100% sensitivity, both in the Padua (88% accuracy) and in the Reggio Emilia series (90% accuracy). However, at both institutions most patients with idiopathic hyperaldosteronism (IHA) were also detected. CONCLUSIONS: Thus, although developed from patients with confirmed Conn's adenoma, a strategy based on multivariate discriminant analysis can be used prospectively for accurate screening for primary aldosteronism. Furthermore, it was proven to be accurate and applicable to patients tested with similar modalities at a different institution. Although this approach did not provide a clear-cut discrimination of Conn's adenoma from idiopathic hyperaldosteronism, it may avoid unnecessary and costly further testing in patients with a low probability of primary aldosteronism.

Adult↗

PubMed1998

Left ventricular systolic function in primary aldosteronism and hypertension.

OBJECTIVE: This study was designed to investigate whether the excess aldosterone found in primary aldosteronism (PA) influences left-ventricular systolic function (LVSF), through a positive inotropic effect METHODS: M-mode and two-dimensional echocardiography and transmitral Doppler flow velocity measurements were performed in 82 patients: 44 with confirmed PA (23 male; 21 female; aged 51.8+/-13 years) and 38 essential hypertension patients (16 male; 22 female; aged 48.5+/-12 years) matched for demography and blood pressure (BP) values. We measured left-ventricular (LV) midwall fractional shortening (MwFSho) and LV circumferential end-systolic stress (cESS, calculated according to Reichek's equation) and analysed the relationship between MwFSho and cESS. RESULTS: These are given as the mean +/- standard deviation. PA patients had significantly higher cardiac index (CI) (3.55+/-0.94 l/m2 vs 2.98+/-0.58, P < 0.005) and lower E wave/A wave time-velocity integral ratio (0.93+/-0.27 vs 1.26+/-0.41, P < 0.001) than EH, whereas mean BP (126+/-12 mmHg vs 128+/-12), MwFSho (17.1+/-2.4% vs 16.3+/-1.9), cESS (118+/-19 Kdynes/cm2 vs 121+/-18) and the relationship between LV MwFSho and LV cESS did not differ between groups. CONCLUSION: These findings confirm that PA patients exhibit: (1) a modest increase of CI; (2) an LV diastolic filling mainly occurring with the atrial kick. However, they do not lend support to the contention that the excess of plasma aldosterone seen in PA is associated with enhanced LV inotropism under resting conditions.

Adult↗

PubMed1997

Remodeling of the left ventricle in primary aldosteronism due to Conn's adenoma.

BACKGROUND: Since hyperaldosteronism has been experimentally related to myocardial interstitial fibrosis, we investigated the effects of hypertension and excess aldosterone due to aldosterone-producing adenomas (APAs) on the heart. METHODS AND RESULTS: In 52 hypertensive individuals, we performed Doppler echocardiography for estimation of left ventricular (LV) wall thickness and dimensions, transmitral LV filling flow velocity indexes, and 24-hour ambulatory blood pressure monitoring. Consecutive patients with APAs (n = 26) and essential hypertension (EH, n = 26) were individually matched for age, sex, race, body mass index, casual blood pressure, and known duration of hypertension. The matched groups were similar for demography, casual and 24-hour blood pressure values and variability, and duration of hypertension but differed for serum potassium, plasma renin activity, and aldosterone levels (all P < .001). A thicker interventricular septum (P = .015) and posterior wall (P = .009) and a higher LV mass index (118 +/- 5 versus 100 +/- 4 g/m2, P = .009) were observed in APA compared with EH patients. Both septum and posterior wall thicknesses had a significant direct relationship with age, plasma aldosterone, and mean blood pressure. The integral of the early diastolic filling wave (Ei) (P = .011) and the ratio Ei/Ai (A wave integral) (P = .038) were lower and the atrial contribution to LV filling was higher (52 +/- 2% versus 46 +/- 2%, P = .038) in APA than in EH patients. The ratio Ei/Ai was significantly (P = .008) inversely related only to age and plasma aldosterone. CONCLUSIONS: In APA patients, the excess aldosterone is associated with both increased LV wall thickness and mass and decreased early diastolic LV filling indexes compared with demographically similar EH with superimposable blood pressure values, profile, and variability.

Adenoma↗

PubMed1997

Renovascular hypertension with low-to-normal plasma renin: clinical and angiographic features.

1. Low-to-normal renin renovascular hypertension (RVH) and the accuracy of renal vein renin ratios were investigated in 129 consecutive patients referred for suspected RVH. Forty-nine had essential hypertension, 24 unilateral renoparenchymal hypertension and 56 renal artery obstruction. Of the latter, 86% were diagnosed retrospectively as RVH, based on fall in blood pressure with correction of renal ischaemia. We measured baseline, captopril-stimulated and renal vein plasma renin activity (PRA) levels, as well as several other parameters. 2. PRA was low-to-normal in 37% of the RVH patients [low-to-normal renin (LNR-) RVH group] and elevated in the remaining 63% [high-renin (HR-) RVH group]. In the LNR-RVH group, low-to-normal renin levels, by immunoreactive active renin and plasma renin concentration measurements, and a blunted response of PRA to captopril, were seen. As compared with HR-RVH, LNR-RVH patients had a longer duration of hypertension (P < 0.05), higher serum K+ (P = 0.04) and lower diastolic blood pressure (P = 0.02). However, they did not differ for the other variables, including the fall in blood pressure after correction of renal ischaemia. Although the number of bilateral stenoses was similar in the two groups, no patient in the LNR-RVH group had total renal artery occlusion compared with 53% in the HR-RVH group (P = 0.00015). The accuracy of renal vein renin indices were high enough to justify their use only in the patients with total occlusion of a renal artery. 3. Thus LNR-RVH is common in patients with longstanding hypertension without a totally occluded renal artery. Since the sensitivity of renin measurements is low, cure of hypertension would be precluded for more than one third of RVH patients, if these tests were a prerequisite for identifying RVH.

Adolescent↗

PubMed1996

Endothelin-1: a scientist's curiosity, or a real player in ischemic heart disease?

Endothelin-1, the most potent endothelium-derived vasoconstrictor peptide identified so far, exerts multiple biologic effects that are potentially relevant for the pathogenesis of coronary atherosclerosis and ischemic heart disease. Since the discovery of the peptide, a good deal of experimental and clinical data have been accumulated to support an important role of endothelin-1 in ischemic heart disease. In experimental animals, exogenous endothelin-1 was found to cause coronary vasoconstriction and, at higher doses, ventricular fibrillation and death. Endothelin receptor subtypes have been demonstrated and pharmacologically characterized in the coronary vascular bed. The plasma levels of immunoreactive endothelin-1 were found to be increased in patients with coronary atherosclerosis, acute myocardial infarction, and angina. Given its growth-promoting and mitogenic action, endothelin-1 has also been suspected to participate in the mechanism of restenosis after PTCA. The purpose of this study was to critically review the experimental and clinical data supporting the involvement of endothelin-1 in ischemic heart disease and the results of more recent studies on the effects of endothelin-1 blockade on experimental myocardial necrosis and restenosis after PTCA.

Angioplasty, Balloon, Coronary↗

PubMed1995

Immunoreactive endogenous ouabain in primary aldosteronism and essential hypertension: relationship with plasma renin, aldosterone and blood pressure levels.

OBJECTIVE: To investigate the role of ouabain in human hypertension and to establish whether immunoreactive endogenous ouabain is secreted by the adrenal gland under the influence of dopaminergic regulation. METHODS: We measured plasma levels of endogenous ouabain by immunoassay, together with other variables, including plasma renin activity and aldosterone levels, in 91 clinically selected hypertensives and 19 healthy volunteers. We also measured endogenous ouabain in adrenal venous blood and the effect of DA2 dopaminergic receptor blockade and stimulation. After a thorough clinical evaluation, 64 patients were diagnosed with essential hypertension and 24 with primary aldosteronism. RESULTS: Plasma levels of endogenous ouabain were higher in essential hypertensives than in controls. Multiple regression analysis showed a significant relationship of mean blood pressure with plasma endogenous ouabain, age and body mass index, but not with other measured parameters. The plasma levels of endogenous ouabain were more than two standard deviations above the mean value for normotensives in 45% of patients with essential hypertension in whom plasma renin activity was normal. Higher plasma levels of endogenous ouabain were found in patients with aldosterone excess, specifically affecting 56% of 17 patients with surgically confirmed adrenal cortical adenoma and one (14%) of seven patients with idiopathic causes. Removal of adenomas lowered blood pressure in half of the patients in whom plasma levels of endogenous ouabain normalized after surgery. Plasma endogenous ouabain levels were similar in venous blood from the adrenal and inferior vena cava, and plasma levels were not influenced by DA2 dopaminergic blockade and stimulation. CONCLUSION: Approximately half of Caucasian patients with essential hypertension and with hyperaldosteronism exhibit elevated circulating levels of endogenous ouabain. The latter do not appear to be secondary to hypertension, are unrelated to plasma renin activity, and may not involve adrenal type-2 dopaminergic receptors.

Aldosterone↗

PubMed1995

Hypertensive cerebrovascular disease and the renin-angiotensin system.

BACKGROUND: Arterial hypertension is the leading cause of cardiovascular disease and is associated with an increased risk of stroke and heart attack. These complications have been largely attributed to the remodeling of the arterial wall, including accelerated atherosclerosis occurring in hypertensive patients. Although the risk of haemorrhagic stroke seems to be directly related to the level of blood pressure elevation, no such tight relationship has been found between blood pressure levels and atherosclerosis. This observation has led to the concept that a number of genetic, humoral, and cellular factors may be involved in atherogenesis in hypertensive patients. SUMMARY OF REVIEW: The experimental and clinical evidence concerning the role of the renin-angiotensin system in cardiovascular remodeling and atherogenesis of the cerebrovascular bed as well as the data supporting an association between angiotensin II and thrombotic stroke are examined. CONCLUSIONS: The contribution of the renin-angiotensin system to the pathogenesis of accelerated carotid artery atherosclerosis and particularly of cerebrovascular disease remains to be definitively proven. However, the bulk of experimental and clinical data are consistent with the hypothesis that the renin-angiotensin system may play a detrimental role.

Angiotensin II↗

PubMed1994

Role of genetic, humoral, and endothelial factors in hypertension-induced atherosclerosis.

Hypertension and atherosclerosis are the two leading causes of cardiovascular morbidity and mortality. They often coexist in individual patients and one may cause and/or aggravate the other. In recent years a widespread application of molecular biology techniques has led to identification of genetic polymorphisms associated with hypertension and cardiovascular events. Several clinical studies have begun to unravel the pathophysiologic diversity of hypertensive patients as well as the heterogeneity of their cardiovascular disease. A number of peptide growth factors, which through paracrine and autocrine mechanisms may be involved in vascular remodeling and atherogenesis in hypertensive subjects, have been identified. The endothelium has been found to play a pivotal role in the control of vascular tone. Given its strategical location, it is likely to work as a sensor and transducer, which mediates the atherogenic effect of blood pressure, hemodynamic, and humoral changes. We discuss herein the role of the genetic and endothelial factors in the light of recent knowledge gained on the biology of peptide growth factors.

Animals↗

PubMed1994

Bronchocentric granulomatosis and central diabetes insipidus successfully treated with corticosteroids.

Bronchocentric granulomatosis (BCG) is a rare chronic granulomatous lung disease that leads to destruction of the airway walls. It has been observed in association with various conditions, but never, so far, been reported to involve the central nervous system. We report a case of histologically confirmed pulmonary bronchocentric granulomatosis temporally associated with a partial central diabetes insipidus (CDI). Although the pathological basis of the posterior pituitary gland involvement was not ascertained, the temporal association of bronchocentric granulomatosis and central diabetes insipidus, as well as the fact that corticosteroid treatment provided stable remission of both conditions after a 10 month follow-up, strongly suggest that central diabetes insipidus was aetiologically related to bronchocentric granulomatosis in this patient.

Diabetes Insipidus↗

PubMed1994

[Genetic basis of arterial hypertension: new findings in molecular research methods].

Arterial hypertension is thought to derive from an interaction between genetic and environmental factors. Primary hypertension is currently deemed to be under complete polygenic control but highly heterogeneous both from the genetic and the pathophysiologic standpoint. In the last few years a widespread application of molecular medicine techniques to epidemiological genetic studies has led to unprecedented progress in unravelling the genetical basis of human hypertension. The current research strategies along with the most recent results in this field are reviewed.

Animals↗

PubMed1993

Effect of evening versus morning benazepril on 24-hour blood pressure: a comparative study with continuous intraarterial monitoring.

In a single-blind, in-patient, crossover study, the influence on the circadian blood pressure (BP) profile of the 9:00 a.m. versus the 9:00 p.m. acute administration of a single dose of benazepril 10 mg, a new angiotensin-converting-enzyme inhibitor, was assessed in 10 hypertensive patients by means of 24-hour intraarterial ambulatory BP monitoring. Mean 24-hour BP for the three treatments (placebo, benazepril a.m., benazepril p.m.) were 155/93, 131/83 and 138/86 mmHg, respectively. No significant differences between the two benazepril schedules were found in terms of either 24-hour or day-time and night-time mean BP values. However, hourly averages showed that benazepril a.m. had a more sustained antihypertensive effect than benazepril p.m., where a loss of efficacy was observed 19 hours after the administration. BP responses to static and dynamic exercise and to cold pressor test were unchanged after both benazepril schedules, as were BP peaks. These results demonstrate that acute benazepril administration markedly reduces systolic and diastolic BP. The morning administration is preferable because it more effectively covers the whole 24 hours than an evening dose.

Adult↗

PubMed1980

[Not Available].

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History, Ancient↗