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Biomedical subjects

C Pecoraro

Publications and source records attributed to C Pecoraro.

34 records · Page 2Linked to original sources

Effects of angiotensin II on plasma ADH, prostaglandin synthesis, and water excretion in normal humans.

To verify whether angiotensin II (ANG II) stimulates ADH release in humans and to evaluate whether endogenous prostaglandins influence the resulting renal effect of ADH, nonpressor and low pressor doses of ANG II were infused in nine normal volunteers under normal conditions (control study) and after prostaglandin synthesis inhibition with aspirin (ASA study). During ANG II infusion plasma ADH increased in both conditions. Plasma PGE2, urinary PGE2, and urinary 6-keto-PGF1 alpha increased only in the control study, whereas they were undetectable in the plasma and significantly reduced in the urine in the ASA study. ANG II caused a significant fall of glomerular filtration rate, renal plasma flow (with an increase in filtration fraction), fractional sodium excretion, and urine output in both studies. Despite the reduced urine output, urine osmolality decreased significantly in the control study, whereas it increased after aspirin administration. These results suggest that intravenous ANG II stimulates ADH release in humans but that the renal effects of the resulting increase in plasma ADH are different depending on the presence or absence of endogenous prostaglandins.

6-Ketoprostaglandin F1 alpha↗

Mechanism of action of indomethacin in tubular defects.

Indomethacin, a potent prostaglandin synthesis inhibitor, has been proven to be effective in a number of tubular defects characterized by enhanced prostaglandin (namely, prostaglandin E2 (PGE2) production, but its mechanism of action is poorly understood. To elucidate further the mechanism(s) by which indomethacin reverses the abnormal tubular functions, five children with different tubular defects (nephrogenic diabetes insipidus, three cases; Fanconi syndrome, one case; and pseudohypoaldosteronism, one case) were treated with indomethacin. Indomethacin, 1 mg/kg every eight hours, was given for 1 week to all children and then was given chronically to four of the children who responded to the drug. Its use was suspended in a 10 year-old-boy with nephrogenic diabetes insipidus because it proved ineffective. To assess the site along the nephron where indomethacin affects the solute and water excretion, an acute water load study was performed in three responsive children before and during the treatment. Indomethacin did not significantly alter the glomerular filtration rate but was effective in reducing diuresis and levels of urinary sodium and potassium excretion. In the child with Fanconi syndrome, indomethacin was also effective in controlling the urinary loss of phosphate, urate, glucose, and bicarbonate. Results of the water load studies show that indomethacin decreases the delivery of solute from the proximal tubule, reduces the fractional free water clearance, and increases the urine-plasma osmolar ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Role of plasma vasopressin in the impairment of water excretion in nephrotic syndrome.

To verify whether or not an increased secretion of ADH may cause the water retention commonly observed in nephrotic syndrome, 16 nephrotic patients and 13 normal control subjects were studied in basal conditions and following a water load or an iso-osmotic blood volume expansion by 20% albumin infusion. In the basal condition there were no differences in plasma ADH, urine output, urinary osmolality (UOsm), and plasma renin activity between nephrotic patients and control subjects; POsm, PNa+, UNaV, and blood volume (BV) instead, were significantly lower in nephrotic patients than in control subjects. Following the water load control subjects reached a minimal UOsm of 82 +/- 12 mOsm/kg at 60 min and excreted completely the ingested water in 150 min; nephrotic patients reached a minimal UOsm of 160 +/- 111 mOsm/kg at 120 min, and the water was eliminated completely in 240 min. Plasma ADH decreased significantly in the first hour following water load only in control subjects. A significant direct correlation was observed between plasma ADH and POsm in control subjects (ADH = -85 + 0.30 POsm, P less than 0.001) but not in nephrotic patients. Plasma ADH was inversely correlated with BV in nephrotic patients (ADH = 15.47 -0.17 BV, P less than 0.001) but not in normal control subjects. In nephrotic patients with reduced BV the expansion of BV with 20% albumin was effective in reducing the plasma levels of ADH and promoting a water diuresis. Our results demonstrate a sustained volume mediated secretion of ADH in the nephrotic syndrome, which is responsible for the impairment in water excretion.

Adolescent↗

Long-term follow-up of minoxidil therapy in refractory hypertension. A prospective trial in patients with various degrees of renal insufficiency.

Thirty patients with various degrees of renal insufficiency (4 on dialysis treatment) and severe hypertension refractory to conventional agents were treated with minoxidil and followed for up to 182 weeks. BP averaging 203 +/- 8.8/125 +/- 4.1 mm Hg supine and 194 +/- 7.8/125 +/- 3.9 upright before treatment, fell to 155 +/- 6.2/92 +/- 3.4 and 146 +/- 6.3/92 +/- 3.2 respectively within 1 week with 5 to 30 mg daily of minoxidil and remained stabilized around these normal values for three years or more. However, increasing doses of the drug became necessary after 52 weeks of therapy. Serum creatinine increased slightly during long-term treatment in most patients suggesting that the fall in renal function with time should be attributed to the natural progression of normotensive chronic renal failure. Adequate dialysis (in the 4 dialyzed patients) and high-ceiling diuretics prevented fluid imbalance during minoxidil therapy, while beta-blocking agents allowed complete control of reflex tachycardia.

Adolescent↗

Water excretion in nephrotic syndrome. Relationship between blood volume and plasma vasopressin.

In order to verify whether or not an increased secretion of ADH may cause the water retention commonly observed in nephrotic syndrome, 12 nephrotic patients and 11 normal subjects were studied in basal conditions and following a water load or iso-osmotic blood volume expansion. A significant direct correlation was observed between plasma ADH and Posm in controls but not in nephrotics. Plasma ADH was inversely correlated with BV in nephrotics but not in controls. Blood volume expansion in nephrotic patients was effective in reducing plasma ADH and promoting a water diuresis. These results demonstrate a sustained volume mediated secretion of ADH in nephrotic syndrome, which is responsible for the impairment in water excretion.

Blood Volume↗

Biological significance of the C3 nephritic factor in membranoproliferative glomerulonephritis.

Serum levels of the C3 nephritic factor (C3NeF), an IgG autoantibody directed against the C3bBb convertase of the alternative complement pathway, and of eight complement components (C1q, C4, C3, C3d, C5, C9, fB and properdin) were measured in 109 serum samples from 27 patients with idiopathic membranoproliferative glomerulonephritis (MPGN) (type I, 20 cases, and type II, 7 cases) and 14 patients with secondary MPGN. Correlations between the concentrations of C3NeF, serum complement levels and progression of the renal damage were studied during the course of the disease in 14 patients with C3NeF activity. The results showed that (1) C3NeF activity was more frequent in patients with type II MPGN than in patients with type I disease; nevertheless there was a high incidence of this splitting activity in patients with secondary MPGN, (2) high levels of the complement components were present in patients with MPGN, (3) low levels of C3 occurred frequently in type II disease and in secondary MPGN, (4) there was no correlation between C3, fB and C3NeF levels, (5) the presence of C3NeF was associated with a more rapid deterioration of renal function. Longitudinal studies showed that serum levels of C3NeF were not satisfactory for monitoring the clinical course of the illness and, in this respect, are similar to the levels of other autoantibodies in patients with autoimmune disease. As MPGN is a clinical syndrome with various pathogeneses, we suggest that the autoantibody, C3NeF, should be considered only as a marker of some forms of MPGN.

Autoantibodies↗

[Vesico-ureteral reflux and vesico-sphincteral dysfunction in children].

The neurologically normal children affected by v.u. reflux frequently have miction disorders. The bladder-sphincter dysfunction can determine high intravesical pressures causing distortion of the vesico-ureteral junction in the same way of anastomotic obstruction. The urodynamic study allows the diagnosis of bladder-sphincter dysfunction and the careful therapeutic management. The medical treatment of the dysfunctional voiding may improve the evaluation of the reflux and reduce postoperatively complications and urinary tract infections. The Authors analyse their experience in the medical treatment of 40 children with vesico-ureteral reflux associated with miction disorders. The reflux resolved after medical treatment in 25% of cases and miction disorders in 50% of cases. The Authors stress the importance of careful diagnosis and treatment to improve results in this group of patients.

Child↗

[Computed tomography and magnetic resonance in the follow-up to interventions for the prosthetic replacement of the carpal bones].

The authors examined with CT and MRI 12 patients submitted to prosthetic replacement of necrotic carpal bones--7 of them because of scaphoid proximal pole posttraumatic osteonecrosis and 5 because of lunate Kienböck's disease. The prosthetic implants were autologous in all patients: they were taken from palmaris gracilis tendon and modified to give them a rounded shape, to adapt them to the new anatomic site. All patients exhibited postoperative limitation in flexion-extension movements; 5 of them reported associated wrist pain. The authors investigated the anatomic reasons of the postoperative symptoms and tried to assess CT and MR diagnostic capabilities in depicting these conditions. CT was performed with thin sections (1.5 mm) and multiplanar reconstructions, with a Philips Tomoscan LX unit. MRI was performed with a GE MR Max Plus unit at 0.5 T and a Medical Advances transmit-receiving extremity coil, on the axial, coronal and sagittal planes, with T1- and T2-weighted sequences. All patients had been submitted to conventional radiography of the wrist. In 6 patients CT and MRI showed severe synovial reaction in the surgical site, with new ligament absorption in 5 of them. In 5 of these patients CT identified some nodular calcifications, while MRI better depicted the fibrotic portion, if present. MRI demonstrated the carpal dorsal intercalated instability which was present in all the patients submitted to scaphoid proximal pole resection; in the patients operated on for Kienböck's disease, volar tilt of the scaphoid was increased. Both kinds of carpal instability were correlated with scaphoid-lunate surgical dissociation. These instabilities were greatly correlated with the postoperative symptoms. Currently, MRI is the gold standard in studying carpal instability and it is therefore fundamental in investigating the complex anatomic and biomechanical features of these patients postoperatively.

Carpal Bones↗