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Biomedical subjects

G Barsotti

Publications and source records attributed to G Barsotti.

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

Dipsogenic factors operating in chronic uremics on maintenance hemodialysis.

Thirst and hyperdipsia of anuric chronic uremics on maintenance hemodialysis and the possible dipsogenic factors were studied. Exaggerated thirst was present in 213 (86%) of the 247 studied patients. It usually started 4-6 h after the end of the dialysis session, persisted during the whole interdialytic period and often disappeared during the subsequent dialysis. Hyperdipsia, as indicated by the high body weight gain (> 4%) in the interdialytic periods, was present in 33.6% of patients. The highest rate of increase of body weight occurred in the first hours following the end of dialysis sessions. Hypernatremia, potassium depletion, increasing plasma urea levels and elevated plasma angiotensin II levels were considered as the possible dipsogenic factors of a nonpsychic nature. Sodium is certainly of paramount importance for its obliged extracellular position, and when sodium intake is elevated, hypernatremia is very likely the cause of exaggerated thirst and weight gain in patients on hemodialysis. Potassium depletion may cause thirst in animals, but this condition is extremely rare in patients on maintenance hemodialysis, who often accumulate it. In these patients it is, therefore, unlikely that potassium depletion is a dipsogenic factor. Increasing serum urea levels exert an evident dipsogenic effect in anephric rats and urea, when infused into normal volunteers, stimulates thirst. The extracellular urea levels in the interdialytic period are certainly higher than the intracellular ones, as a consequence of its continuous accumulation, and this creates an osmotic gradient with a dipsogenic effect. When this gradient is reversed, following hemodialysis (which removes first the extracellular urea), the dipsogenic effect disappears.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Free-hand ultrasound-guided renal biopsy: report of 650 consecutive cases.

In the past 4 years we have carried out 650 percutaneous renal biopsies (PRB), 54 on transplanted and 596 on native kidneys. PRB was performed with a 14-gauge one-piece disposable needle that was introduced free-handedly into the lumbar wall without any form of fixed guidance or support. Ultrasound was used to locate the kidney pole and to follow the progression of the needle tip in the renal parenchyma. The time needed for the whole procedure was about 5 min. The tissue specimen was adequate for histological evaluation in 98.8% of the cases. The prevalence of post-biopsy complications (haematuria, pain, anaemia) was 2.5%. Haematuria was not a common complication (1.6%) in our series, whereas clinically silent perirenal haematoma was common. Mild perirenal bleeding (volume < 5 ml) was found in 40 of a series of 150 patients (26.6%) who underwent ultrasound scan 24 h after the PRB. Haematoma exceeding 100 ml was revealed with US in only 0.6% of the patients. We conclude that free-hand ultrasound-guided PRB makes this technique easier, highly successful, time-saving and almost free of severe side effects.

Adolescent↗
PubMed1993

Plasma parameters of the prothrombotic state in chronic uremia.

We measured plasma parameters of the prothrombotic state, namely thrombin-antithrombin III complex (TAT), fibrinopeptide A (FPA). D-dimer (DD), von Willebrand factor (vWF), tissue-type plasminogen activator (tPA), beta-thromboglobulin (beta TG), platelet factor 4 (PF4) and serotonin (5HT) in a series of 51 adult patients with chronic uremia: 22 were on maintenance hemodialysis (MHD) and 29 on conservative dietary treatment. Serum tumor necrosis factor alpha (TNF) was determined as well. Uremics presented significantly higher levels of TAT, FPA, DD, vWF, TNF, beta TG and 5HT than normal controls. Patients on conservative treatment showed lower levels of TAT, DD, TNF and beta TG than patients on MHD. Our results provide evidence that a prothrombotic state exists in chronic uremia and that MHD patients have a higher degree of hypercoagulation. Both hemodialysis procedure and uremia-related factors are likely to contribute to the hemostatic derangement.

Adult↗
PubMed1993

Dipsogenic effect of urea in rats.

Anephric rats injected subcutaneously with urea in isotonic saline drank much more than anephric control animals receiving isotonic saline alone. The pattern of water intake and urine output of normal rats, repeatedly injected with urea solution, was similar to that of rats injected with dipsogenic hypertonic NaCl and quite different from that of rats receiving furosemide. A well-evident dipsogenic effect (unrelated to the urine output) was observed in normal rats repeatedly injected with urea solution and having a rapid rise of serum urea concentrations. On the contrary, in rats receiving a single load of urea and showing first a very rapid increase, then followed by a slow decrease of serum urea concentrations, the dipsogenic effect was present only initially. These results demonstrate that urea exerts a direct dipsogenic action which may be interpreted as a consequence of an osmotic gradient between the extra- and the intracellular fluid. When this is positive, as in the case of a rapid rise of serum urea levels, cell dehydration ensues and thirst is stimulated. On the contrary, when serum urea levels are decreasing and, presumably, when the intra- and the extracellular concentrations of urea are in equilibrium, no cellular dehydration occurs and thirst does not appear.

Animals↗
PubMed1993

[The use of picotamide in nephropathy with mesangial IgA deposits. The effect on thromboxane generation].

IgA nephropathy (Berger's disease) is one of the commonest forms of glomerular disease, not rarely progressing to renal failure. Hemostatic system activation may play a role in the development of glomerular injury. In a series of 12 adult patients affected with IgA nephropathy we have observed increased plasma levels of D-dimer, a stable end-product of cross-linked fibrin degradation that is considered a reliable index of blood clotting activation, as well as "in vitro" raised generation of thromboxane, the main platelet product of arachidonic acid metabolism that seems to play an important role in glomerulosclerosis. Picotamide, a novel antiplatelet drug acting as thromboxane synthase inhibitor as well as thromboxane receptor antagonist, administered for 8-12 weeks, was effective in reducing thromboxane generation. We conclude that picotamide may be useful in the management of glomerular nephropathy.

Adolescent↗
PubMed1992

Low urine citrate excretion as main risk factor for recurrent calcium oxalate nephrolithiasis in males.

To better define the relative role of metabolic factors in the recurrence of stone formation, we studied the 24-hour urinary excretion of calcium (uCa), citrate (uCit), oxalic acid (uOx) and uric acid (uUa) in 73 male patients with primary calcium oxalate urolithiasis. According to the episodes of stone formation per year, we identified 51 recurrent stone formers (RSF) and 22 single stone formers (SSF). 20 normal adult males constituted the control group (C). uCa and uOx were higher in RSF than in C, but quite similar in SSF and RSF. The only difference between RSF and SSF was uCit, significantly lower (2.06 +/- 1.04 mmol/24 h) in RSF than in SSF (3.22 +/- 1.18 mmol/24 h, p less than 0.001) and in C (3.42 +/- 1.33 mmol/24 h, p less than 0.001). Hypocitraturia (uCit less than 1.5 mmol/24 h) was found in 16 of 51 RSF (31.4%) and in 1 of 22 SSF (4.5%). These data confirm that high levels of uCa and uOx represent a risk factor for lithogenesis, but also strongly indicate the low uCit excretion as the most important urinary abnormality accounting for the recurrence of calcium oxalate stones.

Adult↗
PubMed1991

A special, supplemented 'vegan' diet for nephrotic patients.

High dietary protein intake, in the past recommended for nephrotic syndrome, does not improve hypoproteinemia and may accelerate progressive renal damage. In contrast, low-protein diets reduce proteinuria and preserve renal function in experimental renal models of nephrotic syndrome. In this study, 20 steroid-resistant, nephrotic patients were treated with a pure vegetarian, low-protein diet, supplemented with essential amino acids and ketoanalogues (supplemented vegan diet, SVD) for 4.6 +/- 3.1 months. Before the study, these patients followed an unrestricted protein, low-sodium diet (LSD). Proteinuria, daily urea nitrogen excretion and creatinine clearance decreased significantly on SVD. A similar lowering effect of SVD was observed on serum total cholesterol. Seven of the 20 patients changed from LSD to SVD and vice-versa on 3 occasions, and in all cases, we found an increase of proteinuria during the LSD period. Serum albumin, HDL cholesterol, triglycerides and anthropometric measurements did not change on SVD. Our data suggest that SVD exerts a favorable effect on proteinuria and hypercholesterolemia in nephrotic patients, without inducing clinical or laboratory signs of malnutrition.

Adult↗
PubMed1991

In defense of creatinine clearance.

The ratios creatinine clearance (Crcl)/inulin clearance (INcl) obtained in 523 measurements and reported in 14 papers have been analyzed and the values of CRcl corresponding to those of INcl have been evaluated. The day-to-day coefficient of variation of CRcl has also been measured in 123 persons, including patients with stable chronic renal failure and patients with normal renal function. The data obtained indicate that CRcl is not less sensitive than INcl, and that its changes are not blunted, if compared with similar changes of INcl. The day-to-day coefficient of variation has been found not to be greater than that of INcl. In conclusion, CRcl is not a misleading method to obtain approximate information on renal function, if it is correctly executed and interpreted.

Creatinine↗
PubMed1990

Vegan supplemented diet in nephrotic syndrome.

Thirteen patients (7 males, 6 females, aged 17-68 years) affected by primary, steroid-resistant, nephrotic syndrome and normal renal function were treated with a vegan, low-protein (0.7 g/kg per day) diet supplemented with essential amino acids and Ketoanalogues (VSD) for 3.9 +/- 2.9 months. These patients were studied at the beginning (following an unrestricted protein diet (UPD) supplying about 1 g/kg per day of mixed proteins) and at the end of VSD period. Urinary protein excretion decreased from 8.7 +/- 2.6 to 5.6 +/- 2.4 g/day (P less than 0.01), serum total cholesterol from 334.6 +/- 97.1 to 275.6 +/- 49.4 mg/dl (P less than 0.05). Serum albumin, HDL-cholesterol, triglycerides, and anthropometric measurements (triceps skinfold thickness and middle arm muscle circumference) did not change. Urinary urea nitrogen decreased from 7.5 +/- 1.8 to 3.8 +/- 1.2 g/day (P less than 0.005), according to dietary prescriptions. Creatinine clearance changed from 104.4 +/- 28.7 to 89.3 +/- 16.7 ml/min (n.s.) and no correlation was found with the changes in urinary protein excretion. This data suggest that VSD reduces proteinuria and exerts favourable effects on hypercholesterolaemia. Protein malnutrition was absent in these patients, probably because of the essential amino acids and ketoanalogues supplementation.

Adolescent↗
PubMed1989

Molecular markers of hemostasis activation in nephrotic syndrome.

Fibrinopeptide A (FPA), a sensitive index of in vivo thrombin activity, beta-thromboglobulin (beta TG) and platelet factor 4 (PF4), specific markers of platelet intravascular activation, have been measured in plasma by radioimmunoassays in 23 patients with nephrotic syndrome and in 32 normal subjects. FPA concentration was 2.40 +/- 1.42 ng/ml (mean +/- SD) in nephrotic patients and 1.16 +/- 0.58 ng/ml in normal controls (p less than 0.001); beta TG concentration was 57.9 +/- 33.2 ng/ml in nephrotic patients and 25.7 +/- 7.4 ng/ml in controls (p less than 0.001); PF4 level was not different from controls. These data indicate in vivo blood hypercoagulability and platelet hyperfunction in nephrotic syndrome. Moreover, we have documented a slow in vitro FPA generation pattern (delta FPA): 0.97 +/- 0.51 ng/ml/10 min; this suggests that thrombin activity is predominantly local.

Adolescent↗