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Biomedical subjects

G Montresor

Publications and source records attributed to G Montresor.

10 recordsLinked to original sources
PubMed1993

Interrelation between angiographic severity of coronary artery disease and plasma levels of insulin, C-peptide and plasminogen activator inhibitor-1.

Plasma insulin, C-peptide and plasminogen activator inhibitor-1 (PAI-1) levels were measured in 64 men with coronary artery disease (CAD) documented by angiography. Coronary arteriograms were analyzed, and the severity and diffusion of coronary lesions were quantified by score systems. C-peptide and PAI-1 levels in patients with CAD were significantly higher than in 30 control subjects. Insulin, C-peptide and PAI-1 showed a highly significant correlation with the severity scores for coronary lesions (C-peptide more than insulin), but only a weak correlation with diffusion scores. Highly significant correlations were found between insulin and PAI-1, and even greater ones between C-peptide and PAI-1. It has been proposed that hyperinsulinemia may be involved in the etiology of atherosclerotic cardiovascular disease by dysregulating lipoprotein metabolism and blood pressure. These findings support that hypothesis and suggest that insulin secretion may be an index of the severity of CAD. Because a direct effect of insulin on the cells that synthesize PAI-1 has been shown, the present data further indicate that the effect of insulin on fibrinolysis may be another way by which hyperinsulinemia accelerates atherogenesis.

Body Mass Index↗
PubMed1992

Evaluation of regional body fat distribution: comparison between W/H ratio and computed tomography in obese women.

Measurements of regional body fat distribution as determined by waist-to-hip ratio and visceral-to-subcutaneous adipose tissue ratio were compared in 63 obese women. Subjects were divided into three CT-evaluated tertiles on the basis of visceral-to-subcutaneous adipose tissue ratio (group I, 0.05-0.231; group II, 0.232-0.344; group III, 0.345-0.781). The three groups showed no appreciable differences in body weight, body mass index or total abdominal adipose tissue. Waist-to-hip ratio values were significantly lower in group I than in groups II and III. There was no statistically significant difference between groups II and III. Visceral abdominal adipose tissue was significantly and progressively higher in the three groups. Subcutaneous abdominal adipose tissue was significantly lower in group III than in group I. All metabolic variables and systolic and diastolic blood pressure were higher when visceral-to-subcutaneous adipose tissue ratio cut-off values were increased. Waist-to-hip ratio was significantly correlated with total adipose tissue, body mass index, visceral abdominal adipose tissue and subcutaneous abdominal adipose tissue. Visceral-to-subcutaneous adipose tissue ratio was correlated with visceral abdominal adipose tissue (r = 0.84, P < 0.01) and subcutaneous abdominal adipose tissue (r = -0.28, P < 0.05). There was no correlation between visceral-to-subcutaneous adipose tissue ratio and body mass index or total abdominal adipose tissue. Visceral-to-subcutaneous adipose correlated more closely with metabolic variables than did waist-to-hip ratio. Partial correlations between waist-to-hip ratio and visceral-to-subcutaneous adipose tissue ratio and metabolic variables, adjusted for body mass index, showed statistically significant relationships for visceral-to-subcutaneous adipose tissue ratio, but not for waist-to-hip ratio. Visceral-to-subcutaneous adipose tissue ratio correlated with waist-to-hip ratio in the study population as a whole, but only in group I did the correlation between visceral-to-subcutaneous adipose tissue ratio and waist-to-hip ratio prove statistically significant. The present study demonstrates that visceral-to-subcutaneous adipose tissue ratio is a better index of body fat distribution than waist-to-hip ratio.

Adipose Tissue↗
PubMed1992

Myocardial stunning following coronary angioplasty: protective effects of calcium-channel blockers.

The beneficial effects of calcium-channel blockers against myocardial stunning have been tested in experimental studies, showing that, when added before or during ischemia, a protective effect against postischemia stunning is achieved. The present study was undertaken to test and compare the protective effect of calcium antagonists [nisoldipine (NIS) and nifedipine (NIF)] and nitrates (NIT) against myocardial stunning in patients with coronary artery disease undergoing percutaneous transluminal coronary angioplasty (PTCA) with prolonged inflation as PTCA represents a model of induced acute and severe ischemia for a brief period and might cause myocardial stunning. The study included 30 patients between the ages of 42 and 67 years, all with exercise-induced angina and single-vessel disease, with severe stenosis (80% to subtotal occlusion) localized on the left anterior descending artery and with the absence of collaterals on the coronary angiograms. Moreover, all patients had normal left ventricular (LV) overall function, as well as normal systolic thickening of the anterior wall, supplied by the diseased artery. Patients were randomized to a pre-PTCA treatment with NIT, 80-120 mg/day (10 patients), NIF, 40-60 mg/day (10 patients), and NIS, 10-20 mg/day (10 patients). Pre-PTCA treatment was initiated 7 days before the procedure and continued after. During the PTCA, at the first balloon inflation, an additional dose of 300 micrograms of NIT was injected into the left anterior descending artery through the balloon catheter in the patients in the NIT group, as well as 0.2 mg of NIF in NIF group patients and 0.05 mg of NIS in NIS group patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effect of angiotensin II on proximal tubular reabsorption in normal humans.

The effects of angiotensin II (AII) on proximal tubular reabsorption have been evaluated in 6 healthy volunteers under normal salt and water balance. One-hour clearance periods were performed before, during and after the infusion of pressor doses of AII; in 3 of the 6 subjects, the study was repeated with lower doses of AII. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were determined by the clearances of inulin and PAH, and the fractional excretion of lithium (FELi) was considered as an index of proximal sodium reabsorption. The effects of AII on the fractional excretion of beta 2 microglobulin (FE beta 2M) were also studied. Both doses of AII decreased GFR and RPF and increased the filtration fraction (FF); the modifications of these parameters, as well as the reduction of FELi and the fractional excretion of sodium (FENa) and the increase of plasma aldosterone and of plasma atrial natriuretic peptide (ANP), were more evident with pressor doses of AII, which increased the blood pressure from 129/83 to 142/95 mm Hg (p less than 0.01). AII did not modify FE beta 2M in either study. During AII, FELi decreased less than FENa and both were closely and inversely related to the variations of FF, whilst no relationship was present between FE beta 2M and FF. These results suggest that, in normal humans, the AII-induced rise of FF may be an important factor, even if not the only one, in enhancing the proximal reabsorption of lithium and thus of sodium, whilst it does not affect the absorption of beta 2M.

Adult↗
PubMed1991

Reduced active protection to the cochlea during physical exercise.

The present investigation was designed to evaluate whether dynamic physical exercise is able to modify stapedius reflex (SR) activity and, as a consequence, to influence the amount of temporary threshold shift (TTS). Experimental subjects were 10 normal-hearing male volunteers, aged 27-34 years (mean 30.8). SR parameters in the time-domain were assessed before, during and after submaximal exercise test, performed for 10 min on an ergometer cycle at 50% of maximum work capacity. The same parameters were also investigated in the absence of exercise, at time-matched intervals. In addition, the combined effect of noise and exercise was studied. The outcome of the investigation indicates that dynamic physical exercise depresses the SR and potentiates noise-induced TTS. The mechanisms underlying the present findings are discussed.

Adult↗
PubMed1991

Remodeling of left ventricular geometry and function induced by lacidipine and nifedipine SR in mild-to-moderate hypertension.

The effects of nifedipine SR and lacidipine on blood pressure, left ventricular (LV) hypertrophy, and diastolic function were evaluated in 15 male patients (mean age of 45 +/- 8 years) with mild-to-moderate hypertension. Clinical evaluation and complete echocardiography were performed at baseline (after 15 days of washout). Seven patients received nifedipine SR (20-40 mg twice daily) and eight lacidipine (4-6 mg once daily). Clinical evaluation and complete echocardiography studies were repeated after 1 and 6 months of active treatment. In addition, full echocardiographic evaluations were carried out in 10 normotensive subjects (for comparison). Results were similar with either drug. After 1 month of therapy, systolic and diastolic blood pressures were significantly decreased (p less than 0.05); after 6 months of therapy, further changes were observed, confirming their significance. Analysis of our data suggests that (a) mild essential hypertension induces early modifications of LV geometry with consequent LV diastolic function characterized by a prolonged and incomplete diastolic filling; thus, LV wall thickness may be increased with a simultaneous reduction in LV end-diastolic short-axis diameter and volume; and (b) antihypertensive treatment with calcium antagonists such as nifedipine SR and lacidipine leads to early normalization of LV geometry and diastolic function without a significant change in total LV mass.

Adult↗
PubMed1990

Early regression of left ventricular diastolic abnormalities in hypertensive patients treated with nifedipine.

The effects of nifedipine on blood pressure (BP), left ventricular hypertrophy, and diastolic function were evaluated in 14 patients with essential hypertension (EH). All males with a mean age of 44 +/- 6 years (range 35-58 years), and in ten normotensive subjects (control group) aged 32-42 years (mean age 36 +/- 4). A complete echocardiogram (ECHO) was performed in basal conditions after 1 and 6 months of therapy with nifedipine (20-40 mg/day). Left ventricular echocardiograms (LV ECHO, M-mode, two-dimensional guided) were plotted with a simultaneous ECG tracing by means of a computerized system that allows evaluation of the following parameters: LV end-diastolic and systolic diameters (EDD, ESD); variations in LV diameter and volume during the entire cardiac cycle, and the velocities of such variations; end-diastolic thicknesses of the interventricular septum and posterior wall (ST, PWT); LV mass, mass/volume (M/V) index, end-diastolic diameter/thickness (D/Th) index, and LV ejection fraction (EF). Left ventricular volume curves were obtained and the contributions of rapid filling (RF) and atrial systole (AS) to EDV were evaluated. Filling velocities during RF (vRF) and AS (vAS) were estimated, as well as the isovolumic relaxation period (IR). No significant changes were observed in the heart rate. After 1 month of therapy, systolic and diastolic BP were significantly decreased (p less than 0.05). ST and PWT were reduced, with a simultaneous increase in EDD and EDV (p less than 0.01). LV mass was slightly reduced, as was the M/V index. The D/Th index was increased (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Direct visualization of aorto-coronary bypass grafts by two-dimensional echocardiography: a new clinical application.

An attempt was made to assess noninvasively the patency of aorto-coronary bypass grafts by two-dimensional echocardiography (2-D echo) in 21 patients who underwent myocardial revascularization. Fifteen patients had one graft while the other six had two grafts. All 21 patients underwent angiography 6-18 months after operation. A day before angiography a 2-D echo was performed with the aim of visualizing the bypass grafts. In 18 patients with 23 grafts (13 with 1 graft and 5 with 2 grafts) it was possible to visualize the tract of the graft by 2-D echo; 16 were judged patent on 2-D echo and confirmed by selective angiography, while 5 grafts were considered occluded both on 2-D echo and angiography. The other 2 grafts were considered to be occluded on 2-D echo but angiographic control displayed their patency. In 3 patients 2-D echo failed to visualize grafts that were patent angiographically. These data must be considered preliminary and need validation in a larger number of patients. However it is reasonable to conclude that 2-D echo has a reliable capacity to predict graft patency. Such an application may be of value in sequential control of patients with aorto-coronary bypass surgery, especially when combined with other clinical and/or technical data.

Adult↗