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Biomedical subjects

G Barsotti

Publications and source records attributed to G Barsotti.

At least 37 records · Page 2Linked to original sources
PubMed1998

Secondary hyperparathyroidism in severe chronic renal failure is corrected by very-low dietary phosphate intake and calcium carbonate supplementation.

The main purpose of our study was to verify the effect of a very-low-protein, low-phosphorus diet, supplemented with essential amino acids and keto analogues and with calcium carbonate, on circulating levels of intact parathyroid hormone (i-PTH) in severe chronic renal failure patients with secondary hyperparathyroidism, not treated with any vitamin D preparation. To this aim, we shifted 21 chronic uremics (12 males, 9 females; age 56 +/- 13 years) with serum creatinine >6.5 mg/dl and i-PTH >150 pg/ml, from a standard low-protein diet (0.6 g/kg/day approximately) to a very-low-protein (0.3 g/kg/day), very-low-phosphorus (5 mg/kg/day) diet supplemented with a mixture of essential amino acids and calcium keto analogues (Ketodiet), calcium carbonate (2-4 g/day), iron, and vitamin B12 preparations. The energy supply of both diets was 30-35 kcal/kg/day. Exclusion criteria were a poor compliance with dietary or supplement prescriptions or signs of autonomic hyperparathyroidism. After 4 +/- 2 months of Ketodiet, the i-PTH serum levels decreased by 49% as a mean (from 441 +/- 233 to 225 +/- 161 pg/ml, p < 0.001); serum phosphorus and alkaline phosphatase decreased, whereas serum calcium increased. The great reduction of serum and urinary urea demonstrated a good compliance with Ketodiet, and no sign of protein malnutrition was observed. These findings confirm that even in severe chronic uremic patients dietary phosphorus restriction and calcium carbonate supplementation lower i-PTH serum levels. This is one of the goals of the dietary treatment that can be safely achieved, provided good compliance both with the dietary prescriptions and with adequate energy and supplement intakes.

Adult↗
PubMed1998

Abnormal increase of creatine kinase plasma levels following muscle exercise in nephrotic patients.

Nephrotic syndrome is a protein-wasting disorder affecting total body protein metabolism, often leading to reduction of lean body mass and changes of muscle cell composition. The aim of this study was to investigate the susceptibility to muscle cell damage in nephrotic patients following submaximal physical exercise, by detection of the creatine kinase (CK) plasma level changes. Fourteen patients affected by primary nephrotic syndrome, without chronic renal failure, underwent an exercise test on a cycle ergometer for 20 min at a constant speed (60 rpm). In each subject, the work rate (expressed as watts) was established as 70% of the maximum power theoretically calculated on a sex, age, weight and height basis. CK plasma levels (U/l) were determined before and 1, 3, 6 and 24 h after the exercise. Following exercise, CK plasma levels became higher in nephrotics than in normal controls. That is, the amount of CK increments was greater in nephrotics than in controls from the first hour after the end of exertion. These changes, both as absolute values and as percentage of the basal values, correlate positively to daily urinary protein losses; moreover, an inverse relationship was detected with albumin serum levels. However, no correlation was observed between the amount of plasma CK increases and age, body weight, plasma creatinine, plasma cholesterol or hemoglobin levels. These results demonstrate that a greater than normal increase of CK plasma levels occurs in nephrotics following physical exercise, and that this increment correlates with the severity of urinary protein wasting. This suggests an increased susceptibility to muscle injury in nephrotic patients probably related to protein depletion and/or to modifications of muscle cell metabolism. Further studies are needed to define the pathogenesis of our findings.

Adult↗
PubMed1998

Circulating levels of IGF-I in patients with chronic uremia on conservative dietary treatment.

The assessment of nutritional status is a very important step in the clinical management of chronic uremic patients, because of the influences of chronic renal failure and of dietary manipulations on the energy and protein metabolism. In this study some serum biochemical markers of protein nutrition, including IGF-I and pre-albumin, have been measured in chronic renal failure patients treated with two different low-protein diets, according to the residual renal function for several months. Our results showed no significant changes of IGF-I, pre-albumin or albumin serum levels in the patients treated with a very low-protein diet (0.3 g/Kg b.w. per day) supplemented with essential amino acids and ketoacids, in comparison with the patients on a conventional low-protein (0.6 g/Kg b.w. per day) diet.

Adult↗
PubMed1997

Increased thrombin generation in patients with chronic renal failure.

The plasma concentration of prothrombin fragment 1 + 2 (F1 + 2) is considered a very sensitive parameter for specific detection of latent hypercoagulability. To evaluate the degree of hypercoagulation associated with chronic uremia, we measured F1 + 2 by ELISA in the plasma of 51 patients with severe or end-stage chronic renal failure (35 males, 16 females, aged 22-81 years): 24 on dietary treatment 15 on combined dietary and once a week hemodialysis, and 12 on regular maintenance hemodialysis; 33 healthy subjects served as a control group. Plasma F1 + 2 showed a significant elevation in the group on dietary treatment; it was further increased in the group on once a week hemodialysis, and even more markedly increased in the group on maintenance hemodialysis. In patients on dietary treatment a positive correlation was found between plasma F1 + 2 and serum creatinine. In patients on maintenance hemodialysis, no increase in the F1 + 2 plasma level was found during the course of a single hemodialysis session. Low molecular weight heparin, administered to 7 patients on dietary treatment, caused a marked drop in the F1 + 2 plasma level, providing evidence that the elevation in F1 + 2 indicates an accelerated in vivo thrombin generation rather than impaired renal catabolism. The enhanced coagulation activation appears to be related to the reduction of residual renal function, i.e., to the severity of renal failure, and may contribute to the increased risk of vascular events in uremic patients.

Adult↗
PubMed1996

Laser Doppler flowmeter assessment of skin microcirculation in uremic patients on hemodialysis treatment.

Vascular disease is frequent in uremics and may contribute to tissue malnutrition and damage. The aim of this study was to detect whether uremic patients show also changes of microcirculation and to evaluate the effects induced by hemodialysis (HD) session. Eleven uremics on HD (7 males, 4 females, aged 25-65 years) were studied; 11 healthy subjects, age- and sex-matched, served as controls. Skin microcirculatory basal flow (BF), maximal postischemic flow (PIF-max) and flow motion index (FMI) were determined at the upper limb contralateral to arteriovenous fistula, by means of a laser Doppler flowmeter. The measurements were taken before, at 1 and 2 h after starting HD and 30 min after the end of HD. In uremics, FMI was lower than in controls (mean +/- SD: 15.2 +/- 13.6 vs. 29.1 +/- 7.4%; p < 0.005); just 1 h after the start of HD, a significant improvement (28.4 +/- 17.7%; p < 0.01) versus basal values was observed and it persisted throughout the HD session. No statistical correlation was observed between the changes of FMI and those of plasma levels of Na+, K+, HCO-3, urea, iPTH or rate of ultrafiltration. BF and PIF-max were similar in uremics and controls, and no changes were observed during HD. Our study shows that the physiological flow motion is reduced in the skin microcirculation of uremics on HD. This abnormality is rapidly corrected by HD.

Adult↗
PubMed1996

Hypertension in kidney stone patients.

The prevalence of arterial hypertension (HT) was investigated in 258 patients (171 m, 87 f, 22-68 years) with a history of primary stone disease. HT was detected in 64 patients (24.8%), with no difference between males (25.7%) and females (23.0%). The prevalence of HT by age was very similar to that of a general population, especially in the calcium stone group. The discriminant analysis demonstrated that the composition of stones, other than the age and body weight of the patients, were the main factors associated with HT. As far as the different kind of stone is concerned, the prevalence of HT was higher in patients with uric acid (17/37, 45.9%) and struvite stones (11/27, 40.7%) than in calcium stone formers (35/188, 18.6%) (chi 2 16.31, p < 0.001). The prevalence of hypercalciuria was higher in the calcium stone group than in uric acid or struvite stone patients (36.4 vs. 9.7 vs. 13.7%; chi 2 10.35, p < 0.01). Furthermore, the hypercalciuria showed a trend to be more prevalent in the untreated (47.0%) than in the treated (31.2%) hypertensives, or normotensives (35.1%). Uric acid stone formers were older, heavier and with higher triglycerides and uric acid plasma levels than calcium or struvite patients. Also the struvite stone formers were older than the calcium stone ones. Our data suggest that the prevalence of HT in kidney stone patients and particularly in calcium stone formers is similar to that of a general population. The role of hypercalciuria as the link for HT-urolithiasis association seems quite uncertain. Struvite and uric acid stone formers have higher risk for HT than calcium stone formers, probably due to the old age or to the associated metabolic abnormalities.

Adult↗
PubMed1996

A low-nitrogen low-phosphorus Vegan diet for patients with chronic renal failure.

The nutritional treatment of chronic renal failure with a low-protein low-phosphorus diet (conventional low-protein diet, CLPD) is effective in reducing uremic intoxication, slowing the progression of renal failure and preventing secondary hyperparathyroidism. Unfortunately, in some patients, the poor palatability and the high cost of the protein-free substitutes, together with difficulties in following the diet away from home, can make good compliance difficult, possibly causing low energy intake and malnutrition. Here the results are reported of an attempt we made to overcome these drawbacks, using a diet supplying only natural foods of plant origin in definite proportions to give an essential amino acid supply satisfying the recommended dietary allowance. This is possible thanks to an appropriate cereal-legume mixture, supplying proteins complementary for essential amino acids. Additional positive features of this special vegan diet (SVD) are the high ratio of unsaturated to saturated fatty acids, the absence of cholesterol, and the lower net acid production in comparison with a mixed diet. This study indicates that the results obtained with the SVD are similar to those obtained with the CLPD. Therefore the SVD can be a substitute for the CLPD in the management of patients with mild chronic renal failure. The SVD is the diet of choice when products made of starch are not available or poorly tolerated.

Adult↗
PubMed1995

Platelet-neutrophil interactions in uremic patients: effects on neutrophil superoxide anion production and chemiluminescence.

Isolated resting platelets are able to limit neutrophil activation and then can control the tissue-damaging potential of activated neutrophils. In the present study, platelet-neutrophil interactions have been evaluated in 10 uremic patients; the blood samples have been collected before the hemodialysis session. Twelve normal subjects served as controls. Platelets and neutrophils have been isolated and recombined in an autologous ex vivo system. Anion superoxide production and chemiluminescence (which is related to hypochlorous acid production) have been evaluated after stimulation with N-formyl-methionyl-leucyl-phenylalanine. Coincubation of platelets from normal subjects with autologous neutrophils led to a dose-dependent inhibition of both superoxide anion generation induced by N-formyl-methionyl-leucyl-phenylalanine and chemiluminescence. Instead, platelets from uremic patients have not affected superoxide anion production by autologous neutrophils. The chemiluminescence was reduced by coincubation with autologous platelets only at the highest platelet-neutrophil ratio (100:1). In conclusion, the modulation exerted by platelets towards neutrophil activation can be impaired in chronic uremia. Therefore, the tissue-damaging potential of circulating neutrophils, due to toxicity by superoxide anion and hypochlorous acid, may be increased.

Adult↗
PubMed1995

Oral activated charcoal in patients with uremic pruritus.

Twenty-three chronic uremic patients on maintenance hemodialysis and suffering from severe pruritus were treated with activated powdered charcoal (6 g daily p.o.). In 10 patients pruritus disappeared completely, and in 10 other patients a partial effect was observed. The favorable results persisted for several weeks after discontinuation of the treatment. Only 3 cases were totally unresponsive. No relevant undesirable side effects were observed with the exception of 1 case who showed treatment intolerance. It is concluded that activated charcoal per os is a safe, effective, and low-cost therapy for patients with uremic pruritus, but its mechanism of action is unknown.

Administration, Oral↗
PubMed1995

Ultrasound diagnosis of suspected urinary tract obstruction using a stimulated diuresis test.

The aim of this study was to evaluate whether a stimulated diuresis test associated with ultrasound is able to differentiate pelvic dilation due to atonicity from pelviureteric junction obstruction (PUO). 42 patients (25 f, 17 m) with minimal or moderate renal pelvis dilation revealed by sonography were selected for the test. Three different measurements of the anteroposterior diameter (APD) of the renal pelvis were done at the renal hilus level, by using a transversal ultrasound scan: the first under spontaneous diuresis conditions, the second after hydration with 1.5 liters of water, and the third with a full bladder 15 min after intravenous injection of 20 mg frusemide. All the patients underwent pyelography. Baseline APD (bAPD) linearly correlated with the PAD both after hydration and frusemide (r = 0.89 and r = 0.84, respectively). A descriptive evaluation of the frequency distribution of the bAPD suggested the possibility that the data samples could belong to three populations with different underlying pathophysiological conditions. Correspondence analysis between bAPD distribution and PUO suggested that the best grouping of data was: group 1 (11 patients) bAPD < 13 mm, group 2 (14 patients) 13 > or = bAPD < or = 20 mm, group 3 (17 patients) bAPD > 20 mm (likelihood ratio chi 2 46.36; d.f. = 2). Standard intravenous pyelography showed an increase in pelvis size compatible with PUO in 2 patients from group 2 and in all patients from group 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[The resistance of activated partial thromboplastin time to heparin infusion during hemodialysis].

Activated partial thromboplastin time (aPTT) during heparin infusion in 10 patients on regular dialytic treatment was evaluated. At end-dialysis (3 hours) plasma heparinization ranged between 2000-4000 IU and from the clinical point of view dialytic performance was good. At end-dialysis aPTT was 53 +/- 14 seconds: this value is under the prescribed aPTT prolongation (1.5-2 times baseline values) to achieve a therapeutic heparin plasma level. Physiopathological implications of this aPTT "resistance" to heparin infusion are studied.

Adult↗
PubMed1995

The new nitroderivative ITF 296 improves collateral blood flow in a canine model of coronary thrombosis.

The actions of ITF 296 and isosorbide dinitrate (ISDN), 20, 70, and 200 g/kg/min, on myocardial transmural blood flow distribution during acute thrombotic occlusion of the left circumflex coronary artery (LCX) have been evaluated in seven and three anesthetized open-chest dogs, respectively, and compared with four animals receiving vehicle. Occlusion of LCX was achieved in 14 +/- 2 min by the insertion of a copper coil. This caused transmural myocardial ischemia in the LCX area, while leaving blood flow in the left anterior descending coronary artery (control area) unaffected. Infusion of ITF 296 (200 g/kg/min) increased transmural coronary flow in the border zone and in the control area without affecting blood flow in the central ischemic area. ISDN, given in the same dose, reduced systemic blood pressure but did not affect LCX blood flow. In three dogs with residual perfusion in the LCX central area ITF 296 also increased blood flow. These results confirm that ITF 296 promotes an increase of flow to the border zone, thus possibly reducing the area of myocardial infarction.

Anesthesia↗
PubMed1994

In vivo measurements of fibrin formation and degradation in nephrotic patients.

Intraglomerular fibrin deposition has been implicated as an important pathogenetic mechanism in patients with glomerular diseases and the nephrotic syndrome. To investigate fibrin formation and degradation in nephrosis, we measured fibrinopeptide A by radioimmunoassay and D-dimer by enzyme-linked immunosorbent assay in the plasma of 30 consecutive adult patients with the nephrotic syndrome; in 10 the serum creatinine was more than 2 mg/dl. Both fibrinopeptide A and D-dimer were abnormally elevated in the majority of nephrotics (P < 0.001 vs. healthy controls), providing evidence of increased fibrin generation and lysis "in vivo." A positive correlation was found between fibrinopeptide A and D-dimer (correlation coefficient 0.64, P < 0.001), suggesting a close relationship between fibrin formation and degradation. Calcium heparin, administered to 12 nephrotics, caused a marked decrease in plasma fibrinopeptide A, due to a reduction of in vivo thrombin activity. As enhanced thrombin activity can favor fibrin deposition within the renal parenchyma, as well as vascular complications, it is reasonable to assume that an antithrombotic treatment aimed at controlling thrombin generation may ameliorate the natural history of nephrosis.

Adolescent↗