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Biomedical subjects

V E Andreucci

Publications and source records attributed to V E Andreucci.

At least 37 records · Page 2Linked to original sources
PubMed1991

Renal functional reserve: its significance in normal and salt depletion conditions.

The aim of this study was the evaluation, in healthy subjects, of the renal functional reserve (RFR), that is, the GFR increase induced by a combined infusion of amino acids (AA) and dopamine (D), in conditions of extracellular volume depletion caused by diuretic administration. In particular, this study was undertaken: a) to evaluate whether and to which extent, AA + D can reverse the functional GFR impairment induced by salt depletion, without volume restoration; b) to study whether any relationship may be found between the GFR in normal condition (the so-called "resting" GFR), and/or the renal functional reserve and the GFR impairment induced by salt depletion, in order to understand the role of both "resting" GFR and RFR in the degree of renal dysfunction induced by salt depletion. In control conditions the i.v. infusion of AA + D significantly increased RPF (+ 41% vs. baseline period) with a mean absolute increase of 211 ml/min. A similar pattern was observed in GFR behavior (+31.5% with 34 ml/min of mean absolute increase). A significant inverse exponential relationship was observed between GFR before AA + D i.v. infusion ("resting" GFR) and renal functional reserve (P less than 0.05), suggesting that, in normal conditions, these inversely related parameters may widely vary according to the tone of the glomerular arterioles. Following salt depletion, we observed a variable degree of GFR impairment. Both GFR and RPF were significantly decreased (-25.9%, P less than 0.05 and -29%, P less than 0.05, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Bicarbonate and calcium kinetics in postdilutional hemodiafiltration.

Hemodiafiltration (HDF) is a very effective blood treatment resulting from the coupling of dialysis and hemofiltration and leading to reduction of dialysis time. The aim of this study was to evaluate the balance of bicarbonate and calcium through the filter during postdilutional HDF (with an ultrafiltration flow rate of 70 ml/min) and to verify the effect of ultrafiltration on the kinetics of these two solutes. The study was performed by simultaneously collecting three blood samples (at filter inlet and outlet and after reinfusion) at different ultrafiltration flow rates (12.5-90 ml/min), to measure blood pH, pCO2, plasma total CO2(TCO2), total calcium, ionized calcium and plasma protein concentration. Plasma bicarbonate concentration was calculated by measuring plasma TCO2. The results showed an inverse linear relationship between bicarbonate (r: -0.7938; p less than 0.001) and calcium (r: -0.8731; p less than 0.001) balance and ultrafiltration flow rate. In particular, in postdilutional HDF both bicarbonate and calcium balances through the filter were negative at ultrafiltration flow rates greater than 40 and 55 ml/min, respectively. The negative bicarbonate balance, however, was corrected by reinfusing a substituting solution containing bicarbonate (40 mmol/l). By contrast, the negative calcium balance cannot be corrected by reinfusion and requires a greater calcium concentration in the dialysate and oral calcium supplements.

Bicarbonates↗
PubMed1991

Interleukin-6 production of uraemic haemodialysed patients: effects of different membranes.

Interleukin-6 (Il-6) has a complex spectrum of biological activities (growth and differentiation of B cells and synthesis of acute-phase proteins by liver). To evaluate the role of this cytokine in the inflammatory response induced by blood interaction with haemodialysis membranes, we have investigated Il-6 synthesis and release in supernatant of 24-h cultured peripheral blood mononuclear cells (PBMC) isolated from ten haemodialysed patients and eight healthy control subjects. In haemodialysed patients, blood samples were drawn before and after their usual dialytic treatment with cuprophane membranes and following 1 and 2 months with polymethylmethacrylate (PMMA) membranes. Il-6 was determined by 72-h incubation of serial dilutions of PBMC supernatant with Il-6-dependent cell line 7TD1; dilutions of rIl-6 were included as standard. Compared to Il-6 synthesis in control subjects (3.3 +/- 2.8 U/ml) the patients usually haemodialysed with cuprophane membranes showed significantly greater values (9.8 +/- 4.5 U/ml, P less than 0.02 before the treatment, and 10.4 +/- 6.1 U/ml, P less than 0.05 after the treatment). A significant reduction, in comparison with the values obtained with cuprophane membranes, was obtained after 1 month (5.3 +/- 2 U/ml, P less than 0.02 before the treatment, and 7.5 +/- 6 U/ml after the treatment) and especially after 2 months (3.4 +/- 3.2 U/ml, P less than 0.02 before the treatment, and 4.4 +/- 3.4 U/ml, P less than 0.05 after the treatment) of dialysis with PMMA membranes. In conclusion, our results show increased Il-6 production in haemodialysed patients usually treated with cuprophane membranes, suggesting a chronic stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Acute increase in plasma osmolality as a cause of hyperkalemia in patients with renal failure.

These studies were performed in patients with chronic renal failure to understand the mechanism(s) of hyperkalemia secondary to hypertonic NaCl infusion. In 10 patients, after intravenous infusion of either 5% or 2.5% NaCl (6 mEq per kg body wt for 120 minutes in both solutions), the maximum increase in plasma potassium averaged 0.6 (range 0.3 to 1.3) mmol/liter (P less than 0.01) or 0.3 (range 0.2 to 0.6) mmol/liter (P less than 0.01), respectively. The rise of both plasma potassium and osmolality was significantly higher during 5% NaCl than during 2.5% NaCl infusion (P less than 0.01). A significant linear correlation (P less than 0.01) between plasma potassium and osmolality was observed. Urinary potassium excretion was increased to a similar extent by 5% NaCl and 2.5% NaCl infusion. The observed hyperkalemia, secondary to NaCl infusion, was independent of venous pH, plasma bicarbonate, anion gap, insulin levels, and urinary norepinephrine and epinephrine excretion, and was associated with a fall in plasma aldosterone concentration. In separate studies, nine patients were treated with desoxycorticosterone acetate (DOCA; 20 mg i.m. for three days) before receiving saline (5%) infusion. DOCA did not prevent the level increase in plasma potassium that remained significantly correlated with plasma osmolality (P less than 0.01). In conclusion, hypertonic NaCl infusion in patients with renal failure causes a clinically relevant hyperkalemia despite increased renal excretion of potassium. This hyperkalemia is independent of acid-base or hormonal mechanisms known to regulate extrarenal homeostasis of potassium, and is strictly correlated with a rise in plasma osmolality.

Acid-Base Equilibrium↗
PubMed1990

Absence of acute nephrotoxicity with low doses of cyclosporin: experimental study in the rat.

No study has, to our knowledge, evaluated the acute effects of low immunosuppressive doses of cyclosporin (CsA) on renal function. To establish whether a relationship exists between the dosage of CsA and the onset of nephrotoxicity, 28 rats were studied by renal clearances before (control) and after i.v. administration of different doses of CsA: 3 mg/kg b.w. (group 1); 7 mg/kg b.w. (group 2); 11 mg/kg b.w. (group 3); 15 mg/kg b.w. (group 4). No change in renal function was observed between control and the post-CsA period in groups 1 and 2. GFR (inulin clearance) was decreased vs the control period in group 3 and group 4 (-22% and -37%, respectively, P less than 0.001); the difference between these two groups was statistically significant (P less than 0.01). Effective renal plasma flow (PAH clearance) was similarly decreased in groups 3 and 4 vs their control periods (-21% and -28%, respectively, P less than 0.001) due to the increase of total renal vascular resistance (+41% and +42%, respectively, P less than 0.001). Filtration fraction was significantly decreased by CsA in group 4 (P less than 0.01 vs the control period). PAH renal extraction, urinary volume, and sodium and potassium excretion were similar in all groups before and after CsA. PRA and ADH were significantly increased only in group 4 (P less than 0.01) vs the baseline values. A high and significant relationship was detected between CsA dosage and the decrease of GFR (r = 0.81, P less than 0.001) and RPF (r = 0.612, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1990

Cardiovascular impairment, dialysis strategy and tolerance in elderly and young patients on maintenance haemodialysis.

Cardiovascular impairment is considered a major cause of reduced tolerance to haemodialysis in elderly patients and is thought to require a soft dialysis strategy in these patients. To verify these observations we compared dialysis strategy and tolerance of patients over 65 years old to those of patients under 45 years, since atherosclerotic/involutional changes of vasculature should be quite different in these groups. Seventy-seven elderly and 57 young patients (age 72 +/- 5 and 35 +/- 6 years respectively, mean and SD) were selected from a population of 292 patients undergoing regular dialysis treatment exclusively on the basis of the age criterion. Cardiovascular impairment was found to be greater (as expected) in older than in younger patients, as documented by a larger proportion of diabetic patients (19% vs 3%), a greater incidence of cardiovascular manifestations both before the beginning of dialysis (27% vs 10% of patients affected) and after the beginning of dialysis (35% vs 16%), a greater incidence of ECG abnormalities (78% vs 56%), a longer exposure to hypertension (9.2 vs 3.5 years), and a greater utilisation of digitalis (36% vs 5%) and nitrates (19% vs 2%). Dialysis strategy in elderly patients differed from that in young patients only for a moderately lower blood flow rate (243 vs 279, 244 vs 279, ml/min, males and females respectively). Dialysis sessions were shorter in older than in younger males (11.8 vs 12.4 h/week). The incidence of intradialytic hypotension did not differ significantly between the two groups (44% vs 32%), although the elderly showed a greater pre-to-post-dialysis systolic arterial pressure reduction (21 vs 15 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Role of atrial natriuretic factor in renal adaptation to variation of salt intake in humans.

This study was performed to define the extent to which atrial natriuretic factor (ANF) contributes to upregulate salt excretion in subjects eating a high-salt diet. Eight normal volunteers were first studied at low-salt diet (80 mmol NaCl/day); urinary sodium excretion (UNaV) and plasma ANF (PANF) were measured in the basal condition and during stepwise infusion of human alpha-ANF at 2, 4, 8, and 16 ng.min-1.kg-1. Then the same subjects were shifted to a high-salt diet (400 mmol/day), and UNaV and PANF were measured in the new balance condition. At low-salt diet, UNaV averaged 0.069 meq/min, and PANF averaged 21 pg/ml; infusion of human alpha-ANF raised stepwise both UNaV and PANF (means in meq/min and pg/ml, respectively, were 0.177 and 46, 0.218 and 76, 0.360 and 86, and 0.601 and 182). Infusion of ANF caused a progressive fall of plasma aldosterone and plasma renin activity. Mean UNaV and PANF at high-salt diet were 0.301 meq/min and 35 pg/ml. Thus, by increasing experimentally PANF in a low-salt diet condition to the levels occurring physiologically in a high-salt diet condition, a significant rise in UNaV is evoked, which accounts for approximately 50% of the rise of UNaV that is necessary to balance the increased salt intake.

Adaptation, Physiological↗
PubMed1989

Reversibility of acute cyclosporin nephrotoxicity by dopamine. Micropuncture study in the rat.

The ability of dopamine to neutralise the effects acutely induced by cyclosporin (CsA) on glomerular dynamics was evaluated in four groups of female Munich-Wistar rats, prepared for micropuncture: group I (n = 9), normal rats receiving saline as placebo; group II (n = 10), rats treated with CsA (20 mg/kg b.w. in 1 h); group III (n = 8) rats treated with CsA, as in group II, and then with vasodilating doses of dopamine (1.2-2.0 micrograms/100 g b.w./min in continuous intravenous infusion); group IV (n = 7), rats administered Cremophore EL, the vehicle of CsA, in corresponding doses. Single nephron GFR (SNGFR), glomerular plasma flow (GPF), afferent and efferent arteriole resistances (Ra and Re, respectively), SN filtration fraction (SNFF), ultrafiltration coefficient (Kf) were measured. Body weight, blood pressure and haematocrit were similar in the four groups. GFR was significantly reduced in group II (0.83 +/- 0.08 ml/min vs 1.29 +/- 0.01 in group I, 1.46 +/- 0.25 in group III, and 1.40 +/- 0.09 in group IV, P less than 0.05 vs all the groups), while no statistical difference was detected in urinary volume. SNGFR was significantly reduced in group II vs group I (18.7 +/- 1.8 nl/min vs 30.6 +/- 1.3, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Effects of uremia, acetate and bicarbonate dialysis on beta-adrenergic responsiveness as assessed by epinephrine-stimulated adenylate cyclase.

This study was designed to evaluate beta-adrenergic responsiveness as assessed by the generation of cyclic AMP after the subcutaneous administration of epinephrine in 31 subjects: normal controls, patients with chronic renal insufficiency, hemodynamically stable patients on chronic acetate dialysis and hemodynamically unstable patients with acetate intolerance on chronic bicarbonate dialysis. As compared with controls, only unstable patients on bicarbonate dialysis presented impaired beta-responsiveness, which, in turn, was acutely reduced only after acetate but not bicarbonate dialysis. Our results show that acetate dialysis impairs the beta-adrenergic responsiveness and that the observed beta-hyporesponsiveness in unstable patients with acetate intolerance may represent part of a broader spectrum of autonomic dysfunction which may develop in some patients on chronic hemodialysis.

Acetates↗
PubMed1989

Total or partial percutaneous renal ablation in the treatment of renovascular hypertension: radiological and clinical aspects.

In 15 patients with renovascular hypertension, considered unsuitable for angioplasty or surgery, percutaneous renal ablation was performed by injection of ethanol into the renal vasculature. Partial or complete renal ablation was confirmed by follow-up intravenous pyelography or arteriography. Patients were followed-up for a mean of 24.8 months after therapy and blood pressure was improved in all patients with five being cured. This study shows that percutaneous renal ablation is a useful and successful method of therapy for renal hypertension, and that it should be considered in patients unsuitable for surgery or angioplasty.

Adolescent↗
PubMed1989

Effectiveness of steroid therapy in different stages of membranous nephropathy.

The published studies on histological staging and response to steroid therapy of membranous glomerulonephritis are not consistent. We analysed data from 25 adult patients with stage I (group 1, n = 7) and stage II (group 2, n = 18) disease. The interval between clinical onset and admission was similar in the two groups. At admission all patients had normal creatinine clearance; proteinuria averaged 5.4 +/- 4.0 in group 1 and 9.0 +/- 4.0 in group 2 (g/day per 100 ml GFR). All patients received 6 months steroid therapy (months 1-2, 1 mg/kg b.w. per day; month 3-5: 0.65 mg/kg b.w. e.o.d.; month 6, tapering). After this cycle of steroid therapy, proteinuria declined by 84% in group 1 (five patients being in partial remission, i.e. 0.4-2 g/day, and two patients in complete remission, i.e. less than or equal to 0.3 g/day) and by 47% in group 2 (two patients being in complete remission and six in partial remission). Only 1 patient in group 1 relapsed with nephrotic proteinuria after 36 months, and renal function was still normal in all patients at the most recent follow-up (59 +/- 32 months). In contrast, 14 patients in group 2 had nephrotic syndrome and seven renal insufficiency at the most recent follow-up. We conclude that short-term steroid therapy is effective only in patients with early membranous changes.

Adolescent↗
PubMed1988

Treatment of severe renovascular hypertension by percutaneous transluminal renal angioplasty in patients with solitary functioning kidney. Effects on blood pressure and renal function.

In this study the effects of percutaneous transluminal renal angioplasty on blood pressure and renal function were studied in 9 hypertensive patients with stenosis of the main artery of a solitary functioning kidney. The outcome of the percutaneous dilatation of the renal artery stenosis, and the effects on blood pressure and renal function were evaluated for a mean period of 16.4 +/- 2.13 (SE) months (ranging from 3 to 65 months). A successful dilatation of the renal artery stenosis was shown in all the patients by the aortography performed 1 h after the procedure. At the discharge (7.8 +/- 0.9 days after dilatation), blood pressure was 'cured' in 2 patients and 'improved' in the remaining patients; renal function was improved in all patients who had reduced renal function. At the last follow-up, no restenosis was found in patients who repeated the follow-up angiography; blood pressure was 'cured' in 3 patients and 'improved' in 6 patients, and renal function appeared steadly improved. In contrast with other reports, our results demonstrate that percutaneous renal angioplasty is a safe and effective procedure and should be attempted before considering surgical intervention in patients with artery stenosis of a solitary functioning kidney.

Adult↗
PubMed1988

Treatment of massive hemorrhage after renal biopsy with percutaneous arterial obliteration.

Severe perirenal hemorrhage is a major, although rare, postbiopsy complication. We report a case of a 48-year-old man with a postbiopsy massive bleeding from a ramification of the renal artery supplying the lower pole of the left kidney. Treatment consisted of complete obliteration of the bleeding vessel by helding a percutaneous catether in wedge position during a renal arteriographyc study. Our case shows that percutaneous arterial obliteration is a successful procedure in treating postbiopsy renal hemorrhage, representing an effective alternative to surgical therapy.

Biopsy, Needle↗