PubMed Health⌕ Search

Biomedical subjects

A Siani

Publications and source records attributed to A Siani.

At least 73 records · Page 4Linked to original sources
PubMed1987

Controlled trial of long term oral potassium supplements in patients with mild hypertension.

A 15 week randomised double blind placebo controlled trial of oral potassium supplements (48 mmol daily) was conducted in 37 patients who had mildly increased blood pressure and a normal dietary intake of sodium. After a two month run in and a one week baseline period the patients were randomly assigned to receive either potassium supplements (n = 18) or placebo (n = 19). By the third week of treatment blood pressure in the actively treated group had decreased significantly compared with that in the placebo group, though the decrease reached its maximum after 15 weeks. Urinary potassium excretion increased significantly in the group who received potassium supplements, but no significant changes were found in plasma sodium and potassium concentrations or in urinary sodium excretion. In a subgroup of 13 patients who underwent a further nine weeks of treatment with oral potassium supplements at half of the previous dose (24 mmol daily) their blood pressure, at the end of this second study period, was still significantly lower compared with their baseline value but not with that of the placebo group. These results show that moderate oral potassium supplements are associated with a long term reduction in blood pressure in patients who have mild hypertension.

Administration, Oral↗
PubMed1987

Metabolic effects of long-term therapy with muzolimine and chlorthalidone in hypertension.

Previous short-term studies of muzolimine (a diuretic with frusemide-like activity) had shown that it did not induce a significant change in the serum potassium concentration. In the present study sodium and potassium handling and other metabolic variables have been compared during 16 weeks of therapy with muzolimine and chlorthalidone, a thiazide-like diuretic. During muzolimine treatment, plasma and red cell potassium concentrations remained unchanged, while a significant fall in potassium occurred with chlorthalidone. Neither drug affected the activity of sodium-potassium cotransport or sodium-lithium countertransport in red cells in vitro. Muzolimine and chlorthalidone had similar effects on arterial pressure and on the other metabolic variables tested.

Adult↗
PubMed1986

Altered extracellular calcium homoeostasis in essential hypertension: a consequence of abnormal cell calcium handling.

A number of abnormalities in the extracellular and intracellular handling of calcium in arterial hypertension, namely an increased urinary calcium excretion, a reduced serum ionized calcium level and an enhanced intracellular free calcium concentration, have previously been reported by this and other laboratories. The present study aimed to investigate the handling of an exogenous calcium load in hypertensive and normotensive subjects in order to detect possible differences with regard to tissue calcium metabolism in vivo. A constant rate intravenous calcium infusion (0.2 mmol 2 h-1 kg-1 body wt.) was carried out in the participants. Serum calcium concentrations were determined at regular intervals during the infusion and in the 4 h after the end of the calcium load. Over the same period, urinary calcium excretion was evaluated in timed urine collections. Hypertensive subjects had lower serum ionized calcium levels compared with normotensive subjects at all the experimental points, a finding suggestive of a faster disappearance of calcium from the circulation. The total body calcium clearance, calculated from the area under the curve of the serum calcium concentrations, was enhanced in hypertensive patients (P less than 0.03). Although the renal calcium excretion was higher in hypertension, the renal calcium clearance accounted for only a minor fraction of the total body clearance, suggesting that the reduced serum calcium levels achieved by the hypertensive patients were not explained by the renal calcium leak. The enhanced total body calcium clearance found in hypertensive subjects is therefore due to an increased tissue calcium uptake. This finding provides indirect evidence of an altered cell calcium handling in hypertension.

Adult↗
PubMed1986

Changing the Mediterranean diet: effects on blood pressure.

An increase in the polyunsaturated to saturated fatty acid ratio (P:S) in the diet has been reported to reduce blood pressure in man. We have investigated whether an increase in the percentage of saturated fatty acids in the typical Mediterranean diet would affect blood pressure in a sample of healthy rural population of southern Italy. Fifty-seven non-hospitalized normotensive volunteers (29 male, 28 female, aged 30-50 years) were studied. After a 2-week baseline period on their customary diet (P:S = 0.44), they underwent a 6-week isocaloric dietary intervention with a 70% increase in energy from saturated fatty acids and a corresponding decrease in carbohydrate and mono-unsaturated fat (P:S = 0.23). Thereafter they returned to their usual diet and were followed-up for 6 more weeks (switch-back period). By the end of the intervention period, systolic pressure was increased by 2.6 mmHg in men (P less than 0.05) and by 4.8 mmHg in women (P less than 0.01). Diastolic pressure was not significantly increased, although a significant linear regression of the group average blood pressure over time was observed for both systolic (0.161 mmHg, P less than 0.01) and diastolic pressure (0.107 mmHg, P less than 0.01). After returning to their customary diet, blood pressure returned to baseline (-0.212 mmHg, P less than 0.05 systolic and -0.226 mmHg, P less than 0.01 diastolic). No significant change in body weight occurred throughout the study. These findings suggest that changes in the saturated fatty acid content of the diet with moderate change in the dietary P:S ratio can influence blood pressure to a significant extent.

Adult↗
PubMed1986

Controlled trial of long-term oral calcium supplementation in essential hypertension.

A randomized, double-blind, placebo-controlled crossover trial of oral calcium supplementation was carried out in 18 patients with uncomplicated essential hypertension. After 15 weeks of oral calcium supplementation, 1 g/day, of the patients' habitual diet, the only blood pressure change (compared with the results of placebo treatment) was in the average standing systolic blood pressure, which was significantly reduced (-8.6 mm Hg; p less than 0.01). The 24-hour urinary calcium excretion and the total serum calcium concentration increased significantly during calcium supplementation (p less than 0.05), indicating good compliance with the treatment. The individual blood pressure changes with high calcium intake were found to be inversely related to basal 24-hour urinary calcium excretion (r = -0.69, p less than 0.001 for standing systolic pressure; r = -0.55, p less than 0.002 for standing diastolic pressure). This correlation was independent of age, basal blood pressure, serum calcium concentration, basal 24-hour urinary sodium excretion, and body weight changes during the trial. In particular, a subgroup of six patients, who had a basal 24-hour urinary calcium excretion higher than the mean + 2 SD of a reference healthy population previously described, showed a substantial average blood pressure fall at variance with the other patients in the study. These results do not support the usefulness of an oral calcium supplement in the majority of subjects with mild essential hypertension; however, they suggest that a group of patients with a previously reported abnormality of calcium metabolism may be responsive to this therapeutic measure.

Administration, Oral↗
PubMed1985

The effect of an intravenous calcium load on serum total and ionized calcium in normotensive and hypertensive subjects.

Altered regulation of serum calcium level was proposed to be associated with arterial hypertension and to be dependent on a renal calcium leak or an altered calcium binding to plasma proteins and cell membrane described in human and experimental hypertension. The aim of this study was to analyze the regulation of serum total and ionized calcium levels during an intravenous calcium infusion (0.25 mmol calcium/kg body weight/hr for 2 hours) in a group of untreated essential hypertensives and a comparable normotensive group. Basal serum calcium concentrations did not differ between the two groups, whereas parathyroid activity and urinary calcium were significantly increased in hypertensive subjects. During the calcium load, serum calcium rose almost linearly in all subjects but with a reduced slope in the hypertensive group, which showed serum total and ionized calcium levels significantly lower than those of the controls at the end of the infusion. Our data indicate that hypertensive patients have an altered regulation of serum calcium concentrations, probably due to a different body distribution of calcium, rather than to an altered calcium binding to plasma proteins.

Adult↗
PubMed1984

Changing the Mediterranean diet: effects on blood lipids.

A study was carried out on 48 healthy middle-age men and women habitually subsisting on a "Mediterranean type" diet in a rural area of southern Italy. Their freely chosen natural diet was modified for a period of 42 days by partially substituting animal fats for olive oil. Currently available foods were used, and the subjects maintained their habitual lifestyle. Dietary fat content changed from 33 to 37% of total energy and the polyunsaturated to saturated fatty acid ratio changed from 0.48 to 0.22. The base-line serum total cholesterol of men increased during the dietary intervention period from 214 +/- 30 mg/dl (mean and SD) to 245 +/- 33 mg (+15%). Low-density lipoprotein cholesterol increased 19%, while high-density lipoprotein cholesterol remained unmodified. Women, while exhibiting a similar trend in serum total cholesterol (+16%), showed also a 19% increase in their high-density lipoprotein cholesterol (p less than 0.001). Apoprotein B increased in parallel with low-density lipoprotein cholesterol in both sexes. The results of the study confirm the impact of the dietary factor on blood lipids. They also provide additional evidence on the response of high-density lipoprotein cholesterol to diet in free-living populations.

Adult↗
PubMed1984

Basal parathyroid activity and renal calcium handling during an intravenous calcium load.

Urinary excretion of calcium and urinary cyclic AMP (cAMP), plasma parathyroid hormone (PTH) and ionized serum calcium concentration, and creatinine clearance were measured in 15 healthy humans. In the same subjects, renal tubular reabsorption of calcium was evaluated by analyzing the regression line of urinary calcium excretion rate on rising the level of serum calcium during an intravenous calcium infusion. The regression line intercept on the y-axis, which has been proposed to depend on the calcium reabsorption in the renal distal tubule, was found to be significantly related to both urinary cAMP and PTH levels. The theoretical renal threshold for calcium excretion was directly related to the y-axis intercept and thus also to the index of parathyroid activity. No relationship was found between urinary cAMP or plasma PTH levels and the regression line slope of urinary calcium to serum calcium. In healthy subjects, parathyroid activity significantly affects the extrapolated regression line of urinary calcium to serum calcium by changing the intercept, but not the slope.

Adult↗
PubMed1984

Altered kinetics of an intravenous calcium load in hypertensive patients.

Essential hypertensive (EH) patients have a higher rate of urinary calcium excretion and, according to some reports, somewhat lower levels of serum ionized calcium. The aim of this study was to investigate the kinetics of an i.v. calcium load in EH patients and in normotensive controls. Fifteen EH patients and twelve sex-and weight-matched controls received a constant ionized rate i.v. calcium infusion (0.1 mmol Ca2+/kg body weight/h) for 2 h. Serum ionized calcium and urinary calcium excretion were determined at regular intervals during the infusion and, in two subgroups of seven hypertensives and seven controls, for up to 4 hours later. EH patients had significantly higher excretion rates (P less than (P less than 0.001) and slightly, but not significantly, lower serum ionized calcium compared to controls. The serum ionized calcium concentration attained at 60 and 120 min of the Ca2+ infusion was significantly lower in EH (P less than 0.01) and it remained appreciably lower for up to 220 min from the beginning of the test. The area under the curve of serum ionized calcium calculated at different time points was significantly reduced in the hypertensives. The mean renal calcium clearance of the patients during the infusion and the elimination phase was somewhat higher, but the difference from controls did not reach statistical significance. These data indicate an abnormal handling of a calcium load by patients with EH and raise the possibility that such abnormality may not be due simply to a renal defect but perhaps to an altered calcium distribution among different compartments in the body.

Adult↗
PubMed1983

Long term treatment with tienilic acid or thiazides: comparison of antihypertensive and metabolic effects.

A comparison has been made of arterial pressure and major metabolic parameters during long term treatment with tienilic acid and a hydrochlorothiazide-amiloride combination, using a randomized single-blind study without cross-over. A significant fall in systolic and diastolic blood pressure and no change in most biochemical parameters was observed with both drugs. Serum uric acid concentration was decreased during tienilic acid and was slightly increased whilst subjects took the hydrochlorothiazide-amiloride combination; serum potassium was slightly decreased on tienilic acid. No sign of hepatotoxicity was detected.

Adult↗
PubMed1983

[Echographic study of the inferior vena cava in abdominal neoplastic pathology. Comparison with the inferior cavography].

The authors evaluated the reliability of echography in the involvement of the inferior vena cava in the abdominal tumors. 137 patients were studied with echography and 125 with inferior cavography too. All the diagnosis were confirmed with arteriography and/or CT and/or surgical findings. The reliability of the echographic method was significant, and particularly in case of emboli and tumor invasion.

Abdominal Neoplasms↗
PubMed1982

[Ultrasound in the diagnosis of Wilms' tumor].

Ultrasound (US) play a very important role in the diagnosis of Wilms' tumour. The authors analyze the findings in 12 children affected by this neoplasia. The resolution power of 4 different diagnostic levels is also analyzed. They are: a) mass identification; b) diagnosis of the tumour nature; c) diffusion balance; d) recurrence control. The most relevant resolution power lies in the diagnosis of nature and in the recurrence control.

Child↗
PubMed1982

[Comparative study of echotomography and percutaneous transhepatic cholangiography in the diagnosis of obstructive jaundice].

The authors compare the results of sonography (US) and percutaneous transhepatic cholangiography (PTC) in the study of 48 patients with obstructive jaundice. The results obtained were correlated to various diagnostic levels and to the different causes of obstruction. The analysis of the results led the authors to believe that, in most cases, the association of both techniques is absolutely necessary in order to define the whole diagnostic picture.

Bile Duct Neoplasms↗
PubMed1979

[Radiologic diagnosis of the retroperitoneal masses (author's transl)].

A series of 75 patients with retroperitoneal masses (60 malignant and 15 benign tumours) have been studied. Urography and angiography were employed. The results of the two methods are correlated. The following criteria are taken into consideration: a) site; b) nature; c) extension of the mass. The importance of a precise definition of the extension of the tumour is stressed. In fact this can greatly influence the choice of the therapy.

Angiography↗