Search PubMed⌕ Search

Biomedical subjects

S Boschi

Publications and source records attributed to S Boschi.

At least 55 records · Page 3Linked to original sources
PubMed1994

Endogenous opioid system and atrial natriuretic factor in normotensive offspring of hypertensive parents at rest and during exercise test.

OBJECTIVE: To investigate the effects of the endogenous opioid system on plasma atrial natriuretic factor (ANF) levels during sympathetic hyperactivity. DESIGN: We studied the young normotensive offspring of parents who both had essential hypertension, who are characterized by a hyperactive sympathetic nervous system. METHODS: We assessed plasma beta-endorphin, met-enkephalin, dynorphin B, ANF and noradrenaline levels, blood pressure and heart rate values in eight normotensive offspring and in 10 young normotensive subjects with no family history of hypertension (controls) at rest and during two exercise tests: the first test performed with the infusion of placebo (1.5 ml/min saline) and the second test with the infusion of an opioid antagonist (9.5 micrograms/kg per min naloxone hydrochloride). ANF and opioids were radioimmunoassayed after chromatographic pre-extraction. RESULTS: At rest plasma met-enkephalin, dynorphin B, ANF and noradrenaline values in the normotensive offspring were significantly higher than in the controls. Exercise with placebo significantly raised all hormonal and haemodynamic parameters in the two groups. This increase was significantly higher in the normotensive offspring than in the controls. Naloxone did not modify any parameter in either group at rest, but it enhanced further the rise in plasma noradrenaline levels induced by exercise in both groups. A similar effect of naloxone during exercise was observed for plasma ANF levels in the normotensive offspring. CONCLUSIONS: Our findings show that plasma met-enkephalin, dynorphin B, ANF and noradrenaline levels at rest and during exercise are higher in normotensive offspring than in controls. The effects of naloxone indicate that in normotensive offspring at rest the opioid system does not affect ANF release, whereas during exercise it attenuates ANF hypersecretion, possibly by reducing noradrenaline release.

Adult↗
PubMed1994

Relationship between acute suppression of plasma renin activity and lymphocyte Na+:H+ exchange rate in young patients with borderline hypertension.

The participation of the cellular sodium content and renin-angiotensin-aldosterone system in the development of high blood pressure has been frequently suggested. To elucidate the role of a mechanism responsible for renal sodium reabsorption on the time-course of renin suppression, 16 young borderline hypertensive patients were studied by analyzing the relationship between the level of baseline activation of lymphocyte Na+:H+ exchange and the degree of plasma renin activity (PRA) suppression in response to saline loading. In the whole hypertensive population, a significant correlation (R = 0.64; p < 0.01) was found between the lymphocyte Na+:H+ exchange activity and the percentage degree of PRA suppression induced by saline loading. Urinary sodium excretion was enhanced in patients with lesser activation of lymphocyte Na+:H+ exchange and greater PRA suppression (3.5 +/- 5 vs. 2.4 +/- .1 umol/min/kg; p < 0.05). These findings suggest that a mechanism influencing renal sodium reabsorption as Na+:H+ exchange could also affect the control of plasma renin activity, and concur with the development of salt-sensitive high blood pressure.

Adult↗
PubMed1993

Evidence of a partial escape of renin-angiotensin-aldosterone blockade in patients with acute myocardial infarction treated with ACE inhibitors.

Angiotensin-converting enzyme (ACE) inhibitors have been designed to block the renin-angiotensin system and can represent an effective therapeutic approach in those settings where such a system is active, such as myocardial infarction. In a randomized placebo-controlled study, 10 patients with acute myocardial infarction allocated to treatment with increasing doses of zofenopril calcium and 10 patients allocated to placebo were studied in hospital, within 24 hours from symptoms, during 11 sampling periods to assess the time course of ACE inhibition and renin-angiotensin-aldosterone blockade. Zofenopril administration was followed by a dose-dependent inhibition of in vitro ACE activity (7.5 mg, 65%; 15 mg, 89%; 30 mg, 94.5%) and a progressive increase in plasma active renin. Conversely, plasma aldosterone decreased during the first 3 days of treatment and then returned toward baseline values, as did blood pressure, despite a persistent inhibition of ACE. The present data suggest the existence of an interesting dissociation between the time-course of ACE inhibition and that of blockade of the renin-angiotensin system in patients with acute myocardial infarction. This discrepancy could arise from the combination of an only partial in vivo ACE inhibition and the compensatory increase in plasma renin that occurs during treatment with ACE inhibitors. A better understanding of this relationship would seem to be useful in addressing the correct use of ACE inhibitors in patients with acute myocardial injury.

Aldosterone↗
PubMed1993

Atrial natriuretic factor response to acute volume expansion in borderline hypertension. Role of ACE-inhibition and changes in peripheral venous tone.

Abnormalities in the response of atrial natriuretic factor (ANF) to volume expansion have been reported in hypertensive-prone animals and men as well as in hypertensive patients undergoing ACE-inhibition. To investigate some of the mechanisms affecting ANF release in borderline hypertensive patients (BHT) we have studied 16 subjects by assessing their neuro-humoral and hemodynamic response to a two-hour isotonic i.v. NaCl infusion carried out during short-term administration of either placebo or captopril. ACE-inhibition increased baseline venous distensibility (VV30:1.4 vs 1.6 ml/100 ml; p < .05) and reduced the prompt (45') ANF response to saline loading (10.3 +/- 13 vs 42.7 +/- 15%; p < .05)) without affecting the overall ANF release (120':92 +/- 25 vs 65.8 +/- 20%; NS)). A significant pressor increase in response to NaCl loading was observed exclusively after ACE-inhibition (SBP: 5.2 +/- 2 vs 2.4 +/- 1%; p < .05--DBP: 7.1 +/- 3 vs 2 +/- 3%; p < .025) and occurred along with a peripheral arterial and venous constriction and with an increase in plasma levels of an endogeneous Na+/K+ATPase inhibitor (8.8 +/- 4 vs -2 +/- 4%; p < .05). We conclude that the ANF response to saline infusion is delayed by ACE-inhibition in borderline hypertensives. The abnormalities observed in ANF response could follow the changes in peripheral venous distensibility and contribute to the pressor and neuro-humoral derangements described in borderline hypertensives during volume expansion.

Adolescent↗
PubMed1992

The role of the opioid peptides in the development of hyperinsulinemia in obese women with abdominal body fat distribution.

In this study, we investigated the hypothesis that increased opioid activity may be involved in the development of hyperinsulinemia in women with obesity and abdominal body fat distribution. Two groups of nine obese body (body mass index [BMI], 30 to 40 kg/m2) women with abdominal (A-ob) (waist to hip ratio [WHR] greater than 0.85) or gluteo-femoral (F-ob) (WHR greater than or equal to 0.80) fat distribution were examined and compared with eight normal-weight controls. Basal beta-endorphin levels were higher in the A-ob group than in the other groups. Each woman underwent two oral glucose tolerance tests (OGTT, 75 g glucose). A bolus of naloxone (0.8 mg) followed by a constant infusion of naloxone (0.04 mg/kg/h) or saline was also administered during the glucose challenge in random order, and blood samples for glucose, insulin, and C-peptide were collected at regular times after glucose administration. No difference was observed in basal or stimulated glucose concentrations between the three groups, nor between the saline or naloxone study. However, basal and stimulated insulin levels were significantly higher in obese women (particularly in the A-ob group) than in controls. Naloxone administration, however, did not significantly modify insulin and C-peptide glucose-stimulated concentrations in controls and in the F-ob group, whereas it significantly reduced (by approximately 47%) insulin levels in the A-ob group. Partial correlation coefficients showed a significant negative correlation between percent variation of glucose-stimulated insulin incremental areas during the naloxone study and the WHR in all women considered together (r = .544, P less than .025).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1992

Biphasic lung diffusing capacity: detection of early asbestos induced changes in lung function.

Asbestos related changes in the single breath carbon monoxide diffusing capacity (DLCO) were longitudinally analysed in 14 subjects exposed predominantly to chrysotile asbestos in an asbestos cement factory. These subjects were examined annually over the past nine years; their lung function was initially characterised with increased DLCO as the sole functional abnormality and they had normal chest radiographs. The radiological examination included a chest x ray film and, in the past two years, high resolution computed tomography (HRCT). A biphasic DLCO change was found: an initial increase followed by a relative decrease. The increase in DLCO was mainly caused by an increase in the membrane component (Dm). Indomethacin treatment applied after the sixth annual follow up significantly reduced DLCO and Dm. The decrease in DLCO correlated well with the parenchymal abnormalities found on HRCT, whereas the chest x ray film profusion score for small opacities (ILO classification) was unchanged. In conclusion, the data suggested that, as well as the absolute values of pulmonary function tests, the measurement of progression of functional parameters is essential in the assessment of pleural and parenchymal disease of the lung related to exposure to asbestos. High resolution computed tomography is suggested as the radiological method of choice in subjects with an isolated decrease in DLCO. Exposure to asbestos can be associated not only with a reduction in DLCO, but also with a temporary increase in DLCO caused by a subclinical inflammatory reaction.

Adult↗
PubMed1992

Factors associated with acute salt-sensitivity in borderline hypertensive patients.

The acute sensitivity to sodium loading has been investigated in 26 borderline hypertensive patients (BHT) undergoing acute i.v. NaCl infusion. Measurements included blood pressure (BP), forearm vascular resistance (FVR) and venous distensibility (VV30), plasma renin activity (PRA), plasma aldosterone, plasma atrial natriuretic factor (ANF), and plasma levels of endogenous Na+/K+ATPase inhibitor. Sodium loading was associated with a greater than 8% increase in mean BP in 12 patients defined as salt-sensitive (NaCl-SENS) in comparison to salt-insensitive (NaCl-INSENS) subset. NaCl-SENS patients in comparison to NaCl-INSENS exhibited 1) a greater baseline VV30 (2.1 vs 1.4 ml/100 ml; p less than .005), and a response to saline characterized by 2) increased FVR (21.4 vs -6.5%; p less than .005), 3) blunted PRA suppression (-42 vs -67%; p less than .05), 4) delayed ANF response and 5) release of a Na+/K+ATPase inhibitor. Post-loading cumulative urinary sodium excretion was reduced in NaCl-SENS borderline hypertensives compared to NaCl-INSENS (2.6 vs 3.8 mumol/min/Kg; p less than .05). We conclude that acute salt-sensitivity in BHT is characterized by a blunted hormonal response to sodium loading which could be responsible of the activation of hemodynamic as well as humoral mechanisms leading to progressive blood pressure increase.

Adult↗
PubMed1992

Clinical significance of holes in gloves for dental use: a spectrophotometric analysis.

The aim of this study on latex dental gloves was to establish whether there is any relationship between faults that are detected by filling with water and the entry of liquid into the gloves during use. Twenty-four gloves of different sizes were examined. Large and small holes randomly distributed on the index, middle, and ring fingers, were made in the gloves. The gloves were filled with water and squeezed to detect the amount of water escaping. A mass spectrophotometer was used with the same gloves to quantify the entry of an aqueous solution of potassium bichromate during work. The filling method was effective for revealing all faults in gloves, but it was not able to determine whether there would be fluid entry through the holes during work. While the size of the holes was not predictive for the amount of liquid entering the glove, adherence of the glove to the hand was. Holes of the same size allowed a greater entry of contaminated liquid in adherent gloves than in looser ones.

Dentists↗
PubMed1992

[Variations in neuropeptide Y plasma levels in acute myocardial infarction].

The aim of the study was to measure plasma neuropeptide Y (NPY) in patients with acute myocardial infarction (AMI). Eighteen patients (13 females and 5 males; range 55 to 75 years) admitted both early (n 12; mean preadmission time 3 +/- 2 hours) and late (n 6; mean preadmission time 25 +/- 16 hours) to Coronary Care Unit were studied. Plasma NPY values significantly above normal range (15-25 pg/ml) and early admitted patients (26 +/- 10 pg/ml) have been found in late admitted patients (72 +/- 28 pg/ml; p < 0.05) both on the admission and during the stay in the Coronary Care Unit (96 hours). In early admitted patients no significant correlation was found between both AMI localization and the thrombolytic treatment. A significant increase in plasma NPY levels has been observed in all patients with complicated myocardial infarction (both in subclinic and clinic heart failure or extension of infarct size). According with the literature data our results have shown a significant correlation between increase of plasma NPY levels and failure of myocardial pump. Moreover, the plasma NPY increase which has been observed in preclinic heart failure when plasma catecholamine levels is usually not significantly different from normal values, may be a useful and reliable prognostic marker.

Aged↗
PubMed1992

[Neuropeptide Y and heart failure].

A time course (48 hours) of plasma neuropeptide Y (NPY) levels has been carried out in a male, 66 years old, admitted to Coronary Care Unit with inferior acute myocardial infarction within 1 hour from the onset of chest pain. On admission an increase of plasma NPY levels (38 pg/ml) has been observed. The plasma NPY value decreased to normal range (15-25 pg/ml) within 12 hours and increased again (53 pg/ml) within 12 and 24 hours. A decrease in plasma NPY values to normal range has been observed within the second day in the Coronary Care Unit. A clearcut diuresis decrease, without pulmonary signs of heart failure, was present from 12 to 24 hours followed by marked polyuria within the second day. These data point out a relative importance of NPY in the diuresis adjustments. Thus, plasma NPY measurement might be a more reliable prognostic indicator of heart failure than plasma catecholamine levels. However, further investigations have to be performed.

Aged↗
PubMed1991

Atrial natriuretic factor modulates the plasma levels of a Na+/K+ATPase inhibitor in volume expanded borderline hypertensives.

To evaluate the existence of a relationship between atrial natriuretic factor (ANF) and plasma Na+/K+ATPase inhibitory activity in humans, we examined the hemodynamic and humoral response to volume expansion in 41 borderline hypertensive patients (BHT) with either normal (n = 33) or low plasma renin activity (n = 8). The study was carried out by measuring blood pressure, forearm circulation, plasma renin activity (PRA), ANF, and plasma levels of an endogenous Na+/K+ATPase inhibitor before and after 2 h of acute intravenous NaCl infusion (0.22 mL/min/kg bodyweight). The early (45 min) changes of ANF and those of Na+/K+ATPase inhibitory activity attained at the end of saline infusion were inversely related in BHT with normal PRA and directly related in the low-PRA population (r = 0.64). The time-course of ANF response to sodium loading was significantly delayed in BHT characterized by normal venous distensibility. They also showed a greater increase in plasma Na+/K+ATPase inhibitory activity occurring with an hypertensive, vasoconstrictive, and sodium retaining response as well. We conclude that in normal PRA borderline hypertensives, ANF may modulate the release of a plasma Na+/K+ATPase inhibitor in a setting where extracellular volume is acutely expanded. Our findings also suggest that dissimilarities in peripheral venous distensibility are able to influence the time-course of ANF response. The blunted ANF increase observed in response to NaCl loading in a subset of BHT could represent an early marker of the attitude of such patients to develop high blood pressure leading to the release of a Na(+)-pump inhibitor and influencing individual salt-sensitivity.

Adult↗
PubMed1991

Plasma concentrations of atrial natriuretic factor and hemodynamics in pregnancy-induced hypertension.

Plasma values of atrial natriuretic factor (ANF) were evaluated in 31 women with pregnancy-induced hypertension (PIH) and 31 normal pregnant women at the same age of gestation. In 27 women with PIH and 27 normal pregnant women forearm venous tone (FVT) was evaluated by Strain Gauge Plethysmography. Forearm vascular resistance (FVR) was measured as the ratio of mean blood pressure (MBP) to forearm blood flow. In addition Cardiac Index (CI) by means of transthoracic electrical bioimpedance and total peripheral vascular resistance (TPR) (with the Frank Equation) were also measured. In comparison with the normal pregnant women, the women with PIH had similar values of hematocrit (as an index of plasma volume) and significantly higher levels of FVR and TPR, while ANF plasma values did not differ significantly. Subdividing the women with PIH in relation to the presence of proteinuria (greater than or equal to 0.3 g/l), those with proteinuria, in addition to significantly higher levels of FVR and TPR, had significantly higher levels of FVT than normal pregnant women, while ANF plasma values were higher even though the difference was only near the level of significance. Hypertensive women with proteinuria also had higher values of FVT than hypertensive women without proteinuria. By means of multiple regression ANF did not show any significant correlations with hematocrit or sodium excretion. Hypertension with proteinuria seems to represent a more severe form of the disease in which, in addition to the probable influence of other factors such as the renin-angiotensin and prostaglandin systems, a greater increase in peripheral sympathetic tone than in hypertension alone appears to be present, causing a reduction in venous compliance in addition to the elevation in FVR and TPR, with increase in central blood volume and atrial stretch. This may explain the higher ANF plasma levels in these patients in comparison with normal pregnant women, even though the absence of a significant correlation of ANF with hematocrit and the fact that ANF increase was only near the level of significance may suggest a change in the relation between ANF secretion and atrial volume receptors in pregnancy either normal or complicated by hypertension. ANF does not seem to play an important role in water and sodium excretion in PIH probably because of the presence of very high plasma levels of hormones such as aldosterone, progesterone and oestriol which, together with renal prostaglandins, seem to be involved in diuresis and natriuresis in pregnancy.

Adult↗
PubMed1991

Lenticulostriate arteries in aging process: an angiographic study.

Histological studies describe in detail the changes of the small arteries wall with controversial results concerning lumen narrowing during the aging process. In this study, the anatomic and the angiographic parameters of the medial and lateral lenticulostriate arteries were analysed in 64 carotid angiograms. Only 20% of the total number of lenticulostriate arteries were shown on angiograms. Collateral branches were rarely visible, especially those of medial group. The course of the lenticulostriate arteries was mostly straight or moderately tortuous. No significant differences were noted in any of the measured parameters when compared with the age (p greater than 0.05). It appears that age-related changes spread over external layers of small arteries, with no lumen narrowing or filling defect.

Adolescent↗
PubMed1990

Pattern of peripheral venous response to volume expansion in borderline systemic hypertension.

An increased venous tone responsible for changes in systemic hemodynamics has been described in borderline hypertensive patients along with the release, in response to intravenous sodium chloride, of an endogenous sodium ion/potassium ion adenosine triphosphatase (Na+/K+ ATPase) inhibitor with vasoconstrictive properties. The hemodynamic and humoral effects of a 2-hour intravenous saline infusion were studied in 25 borderline hypertensives characterized on the basis of their forearm venous distensibility (VV30) in normal (n = 15) and low (n = 10) VV30. VV30 was slightly reduced by saline in the entire hypertensive group (1.47 vs 1.36 ml/100 ml; p less than 0.05), whereas blood pressure and plasma Na+/K+ ATPase inhibitor were unchanged. Normal VV30 showed a sudden increase in plasma Na+/K+ ATPase inhibitor in response to saline associated with an increase in blood pressure, a forearm arterial and venous constriction, and a sluggish suppression in plasma renin activity, whereas low VV30 exhibited a completely opposite pattern. The changes in plasma Na+/K+ ATPase inhibitor inversely correlated to VV30 decreases in borderline hypertensives with normal VV30 (r = -0.49; p less than 0.05), whereas they did not in all hypertensive patients. Atrial natriuretic peptide response to saline infusion was delayed in normal VV30 and inversely related to the changes in Na/K+ ATPase inhibitory activity (r = -42; p less than 0.05) attained after 2 hours of infusion in the entire hypertensive population. Results of this study suggest the ability of acute volume expansion to reduce peripheral venous distensibility in borderline hypertensive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Purification of a Na+/K+ ATPase inhibitor from borderline hypertensives' plasma.

Increasing experimental evidences suggest an involvement of an endogenous Na+/K+ ATPase inhibitor in regulating water and electrolytes balance as well as in the pathogenesis of hypertension. However, conflicting results on the nature and the chemical structure of this substance still make it difficult to understand exactly its physiological mechanism of action. In the present study an attempt was made to purify a Na+/K+ ATPase inhibitor from hypertensives' plasma by solid phase extraction followed by 2 HPLC steps using reverse and normal phase columns. The fractions, from both columns, were able to inhibit Na+/K+ ATPase, 3H-ouabain binding to enzyme, ouabain sensitive 86Rb uptake and pNPPase activity in a manner not affected by boiling. Ultrafiltration experiments demonstrate that inhibitory activity is largely due to a low-molecular weight substance. These findings seem to confirm the presence in hypertensives plasma of a Na+/K+ ATPase inhibitor with some similarities with ouabain.

Chromatography, High Pressure Liquid↗
PubMed1990

Usefulness of nicorandil in congestive heart failure.

Rest and exercise hemodynamic and hormonal effects of nicorandil, a nicotinamide-nitrate vasodilator, were assessed in 9 patients with New York Heart Association class II or III congestive heart failure (CHF) and left ventricular ejection fraction less than or equal to 40%. Single oral doses of placebo and 40 and 60 mg of nicorandil were given in a double-blind, randomized trial. Hemodynamic measurements were assessed at rest, up to 8 hours after dose and at peak exercise performed on an upright cycloergometer 1 hour after the dose. Forearm blood flow and venous capacitance were measured by plethysmography 45 minutes after dose. Plasma noradrenaline and plasma renin activity were assessed 1 hour and 2 hours after dose, respectively. Data were analyzed by analysis of variance. Peak effects were observed between 30 and 60 minutes after dose. Mean blood pressure decreased from 86 +/- 7 mm Hg after placebo to 78 +/- 7 mm Hg after 40 mg (p less than 0.05) and to 78 +/- 7 mm Hg after 60 mg (p less than 0.05) of nicorandil. Mean pulmonary artery pressure decreased from 24 +/- 11 to 15 +/- 17 mm Hg (p less than 0.05) and to 17 +/- 7 mm Hg (p less than 0.05) and mean pulmonary wedge pressure decreased from 15 +/- 8 to 9 +/- 4 mm Hg (p less than 0.05) and to 10 +/- 5 mm Hg (p less than 0.05). The changes were significant up to 6 to 8 hours after both doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗