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Biomedical subjects

G Panzetta

Publications and source records attributed to G Panzetta.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effects of acetate on glucose metabolism and cellular ATP content during hemodialysis.

In view of multiple interactions of acetate with intermediary metabolism, we studied the effects of the exogenous acetate load during dialysis on glucose and energy metabolism. IV glucose tolerance test (glucose 0.33 g/kg BW) and platelet ATP content were evaluated in 16 patients before and after a single hemodialysis session with acetate 38 mEq/l in the dialysate. IV glucose tolerance was greatly impaired in all patients after hemodialysis (K: 1.08 +/- 0.30 vs predialysis value of 2.05 +/- 0.85, p less than 0.001). Platelet ATP content was unchanged by dialysis (3.74 +/- 1.02 mumol/10(11) PLTs before and 3.55 +/- 0.69 mumol/10(11) PLTs after), however, individual variations in platelet ATP content ranged from +32 to -31% of the initial values. Postdialysis plasma acetate levels ranged from 1.5 to 9.2 mmol/l and were inversely correlated with postdialysis glucose tolerance test (r: -0.61, p less than 0.01) and platelet ATP content variations (r: -0.51, p less than 0.05). Our study demonstrates that glucose utilization is acutely impaired by acetate dialysis and suggests that the reduced glycolytic activity may be due to a negative feed-back mechanism in the presence of exogenous fuel. It also demonstrates a great variability in platelet ATP content following hemodialysis, which probably depends on the different patients' ability to oxidize acetate.

Acetates↗
PubMed1986

Antibacterial interaction of cefuroxime and serum from uraemic patients.

A strain of Proteus rettgeri was exposed to combinations of subinhibitory concentrations of cefuroxime and serum from normal subjects and from uraemic patients (on conservative and on haemodialysis treatment) and the antibacterial activity of these was determined. Cefuroxime and normal serum gave a synergistic effect. Compared with controls, the combination of cefuroxime and uraemic serum from patients on conservative treatment showed a reduced inhibitory effect. The antibacterial activity of the combination including serum from dialysis patients was similar to that with normal serum; however, this was due to the greater activity of serum from these patients than of serum from normal subjects, and no synergistic interaction with cefuroxime was demonstrated. An alteration of bacterial growth was observed in the presence of uraemic serum. No clearcut correlation was found between the serum concentrations of uraemic metabolites and the antibacterial activity of the combination.

Blood Bactericidal Activity↗
PubMed1986

Clinical features of patients with solitary kidneys.

A clinical study was performed in 2 groups of patients with solitary kidneys, followed for 11-146 months. Group 1 had 9 patients (7 males and 2 females, aged between 23 and 68 years) with unilateral renal agenesis. Group 2 had 13 patients (9 females and 4 males, aged between 27 and 70 years) who underwent unilateral nephrectomy for the following reasons: hydronephrosis secondary to ureteropelvic junction stenosis, 7 patients; renal trauma, 4 patients; benign neoplasia, 2 patients. During the follow up, urinary protein excretion of more than 300 mg/day was observed in 9 patients, 3 in group 1 and 6 in group 2. Eleven patients, 8 in group 1 and 3 in group 2, were hypertensive (diastolic blood pressure higher than 95 mm Hg). Hyperuricemia was observed in 14 patients, 10 in group 1 and 4 in group 2. Seven patients, 4 in group 1 and 3 in group 2, had a significant deterioration of renal function. Neither proteinuria nor renal failure were observed before at least 10 years had elapsed since the anatomic condition of solitary kidney had been established. A surgical renal biopsy was performed in 1 patient with unilateral renal agenesis and showed focal glomerular sclerosis. This study adds support to the view that the reduction of 50% of the renal tissue may be a risky situation in humans as well as in animals.

Adult↗
PubMed1986

Clinical status and acid-base balance during biofiltration in patients with acetate dialysis intolerance.

Nine patients intolerant to acetate hemodialysis were treated with biofiltration. This consisted in a 4-h acetate hemodialysis during which an additional 2 liters of ultrafiltrate were replaced by a bicarbonate solution (100 mEq/l). Hypotensive episodes disappeared and six out of nine patients were symptom-free during the session. Compared to standard hemodialysis, arterial blood bicarbonate and pO2 did not drop during biofiltration. The anion gap did not change during standard hemodialysis, but was significantly reduced during biofiltration (24.5 +/- 2.9 vs 19.9 +/- 1.4 mEq/l). In our conditions clinical results were positive with biofiltration. On the basis of anion gap changes and preliminary results of plasma acetate determinations, it is suggested that a better cellular metabolism of acetate may be induced by bicarbonate infusion.

Acetates↗
PubMed1986

Biofiltration in the treatment of patients with acetate dialysis intolerance.

Nine patients with intolerance to acetate hemodialysis were treated with biofiltration. It consisted of a 4 hour acetate hemodialysis during which an additional 2 liters of ultrafiltrate was replaced by a bicarbonate solution (100 mEq/l). Hypotensive episodes disappeared and six out of nine patients were symptomless during the session. Compared to standard hemodialysis, arterial blood bicarbonate and pO2 did not drop during biofiltration. Serum acetate levels, which were abnormally high in patients during standard hemodialysis, were reduced during biofiltration to the levels of a control group of acetate tolerant patients. Our data show that positive clinical results are obtained with biofiltration and suggest that they can be due to a better cellular metabolism of acetate induced by the bicarbonate infusion.

Acetates↗
PubMed1985

Progression of renal failure in patients with renal disease of diverse etiology on protein-restricted diet.

The rate of progression of early renal failure was evaluated in three groups of adult patients with renal disease of diverse etiology on dietary protein and phosphorus restriction (about 0.6 g/kg of protein, 700 mg of phosphorus) and in a control group of 22 patients with the same renal disease, retrospectively studied, on a free diet. Group 1 had 33 patients with chronic glomerulonephritis (CG), initial serum creatinine (Scr) of 1.4 to 4.3 mg/dl (mean, 2.20), followed for 5 to 94 months (mean, 44). Group 2 had 17 patients with polycystic kidney disease (PKD), Scr 1.3 to 4.7 mg/dl (mean, 2.40), followed for 8 to 81 months (mean, 42). Group 3 had 28 patients with primary chronic pyelonephritis (CP), Scr of 1.5 to 4.5 mg/dl (mean, 2.57), followed for 9 to 92 months (mean, 41). The control group had 22 patients (11 with CG, five with PKD, and six with CP), with Scr 1.7 to 4.1 mg/dl, followed for 6 to 72 months (mean, 24). In the regression analysis between reciprocal creatinine and time, the slopes were -0.0017, -0.0025, and -0.00016 dl/mg/month in the three patient groups on a protein-restricted diet, respectively. The difference between both groups 1 and 2 and group 3 was statistically significant (P less than 0.05). The slopes in patients on a free diet were significantly greater than those found in patients on a protein-restricted diet. The actuarial survival probability at 72 months, assuming as "renal death" a Scr of 10 mg/dl, was 45% in patients with CG, 44% in those with PKD, and 67% in those with CP on a protein-restricted diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1985

Hypertension of polycystic kidney disease: mechanisms and hemodynamic alterations.

32 polycystic kidney disease (PKD) patients, 16 with normal 16 with variably decreased renal function, were studied; 12 were normotensive, 20 were hypertensive. Mean arterial pressure (MAP) was 90 +/- 8 mm Hg in the normotensive group and 117 +/- 17 in hypertensive patients; plasma renin activity (PRA) was similar. The glomerular filtration rate (GFR) was lower, but not significantly, in the hypertensive group and plasma volume (PV) was higher in hypertensive patients (normotensive 40.25 +/- 3.47 ml/kg body weight; hypertensive 46.30 +/- 3.54). No correlation was found between MAP, and PRA or GFR but MAP correlated with PV. Cardiac output was higher in hypertensive patients (normotensive 3.48 +/- 0.70 l/min/m2; hypertensive 3.89 +/- 1.47), also total peripheral resistance was higher in the hypertensive group (normotensive 2,035 +/- 503 dyn/s/cm-5/m2; hypertensive 2,577 +/- 808). Cardiac output and PV showed a high degree of correlation, but no correlation was seen between total peripheral resistance and PV, or PRA. The hypertensive patients were divided into two groups: one with hypertension of less than 2 years duration and one with more than 2 years but with similar GFR, PRA, PV and hemodynamic pattern. Our data indicate that hypertension in PKD is volume-dependent; that the increase in PV was not related to the loss of GFR, and that the role of the renin-angiotensin system in maintaining the hypertensive state is not well defined. Hemodynamically hypertension is characterized by high cardiac output and total peripheral resistance independent of the duration of hypertension.

Adult↗
PubMed1985

Dietary problems of the dialysis patient.

The patients on regular dialysis treatment (RDT) usually experience an adaption phase that may sometimes be complicated by intercurrent catabolic episodes before the steady state is reached. In all these clinical settings, and especially during the catabolic episodes, a correct nutritional evaluation is of great importance. The main abnormalities in body composition and metabolism, which may affect the nutritional status in these patients, are reviewed. The caloric intake should provide the ideal amount of 35 kcal/kg b.w., which seems to be critical in maintaining an ideal body weight. A protein intake of 1.0-1.2 g/kg b.w. is adequate to keep a nitrogen balance and to prevent excessive nitrogen-containing waste product accumulation. Carbohydrates should represent 45-50% of total caloric intake and monomeric carbohydrates should be limited. Lipids as 35-40% of total caloric intake are recommended with the polyunsaturated to saturated fatty acid ratio being 1.0. Phosphate intake should not exceed 900-1,200 mg. Calcium supplements are required up to a total intake of 1,500 mg. During the catabolic phases, however, both the caloric and nitrogen intakes should be increased to meet the increased needs of the patients.

Acid-Base Equilibrium↗
PubMed1985

Carnitine kinetics during dialysis. Evidence of unilateral transport from tissues to plasma.

Plasma total and free carnitine concentrations were measured in 14 patients during a 4-hour hemodialysis session at 40-min intervals. Although postdialysis carnitine levels were lower than predialysis levels, they did not drop progressively and rebound occurred early or late. While no relationship was seen between pre- and postdialysis carnitine values, an inverse correlation was found when the predialysis value was compared with an end-dialysis to predialysis ratio. Our data are not consistent with a first-order elimination kinetics of the molecule and suggest that during dialysis carnitine may be actively released from tissue stores to plasma pool. The finding of an inverse correlation between the fractional change (post-pre ratio) of plasma carnitine and its predialysis level suggests that plasma carnitine supply from cells is more active when plasma carnitine levels are lower.

Adult↗
PubMed1985

Body composition and nutritional status in patients on continuous ambulatory peritoneal dialysis (CAPD).

Total body water (TBW), extracellular water (ECW), exchangeable potassium pool (EKP), and alkali-soluble nitrogen in skeletal muscle tissue (N) were determined in 9 CAPD patients on treatment from 5 to 14 months (mean 8.6 months). The parameters were reevaluated in 6 of these patients 5 to 13 months later (mean 8.6 months). The mean value of TBW was normal and directly correlated to body weight (BW), but TBW was abnormally distributed between extracellular and intracellular space. ECW volume was significantly lower than the predicted value (12.1 +/- 1.4 versus 16.8 +/- 1.9 l) and out of proportion to TBW (34.8 +/- 3.9% versus 47.8 +/- 1.5%). The calculated intracellular water, therefore, appeared clearly hyperexpanded. The mean value of EKP was slightly reduced, but in three patients there was a 25% reduction. N content was low in 5 out of 9 patients. When the parameters were re-evaluated BW and TBW were unchanged in two subjects. A third patient showed a simultaneous increase in both BW (12.7%) and TBW (19%). TBW variations (+19%, -23%, -24%) without changes in BW were seen in three patients. The mean value of EKP was unchanged, but there was a 25% reduction in one patient. N content improved in two and worsened in one of the three patients in whom it was determined. The data suggest that cell overhydration was the distinctive feature in our CAPD patients, and that the evolution of the nutritional status was variable, since the patients could remain stable, gain or loose body fat, and probably change their lean body mass.

Adult↗
PubMed1984

Effects of different forms of dialytic treatment on serum antibacterial activity in patients with chronic renal failure.

The antibacterial activity of fresh and heat-inactivated normal serum was compared with that of sera from patients with renal failure: 16 on diet, 9 on regular hemodialysis (HD) and 9 on continuous ambulatory peritoneal dialysis (CAPD). The antibacterial activity was determined on Proteus rettgeri (Sanelli) by a turbidimetric method. The inhibitory activity of fresh serum was only slightly decreased in nondialyzed uremic patients, whereas it was significantly impaired in CAPD and HD patients. Heat-inactivated normal serum (56 degrees C, 30 min) lost its antibacterial activity. Only CAPD patients' sera behaved as the normal ones. In fact, a consistent residual antibacterial activity was found in heat-inactivated sera of nondialyzed and hemodialyzed patients. The results are in keeping with the view that uremic patients have reduced host-defence reactions. Dialysis treatment appears to further depress the antibacterial capacity of uremic patient's sera. The residual antibacterial activity of heat-inactivated sera is due to substances, not present in normal controls, which act with a mechanism independent of the complement system. CAPD seems more effective than hemodialysis in removing these substances.

Adult↗
PubMed1984

Body fluid spaces in patients on CAPD.

Total body water (TBW) and extracellular water (ECW) were determined in 9 CAPD patients on treatment from 5 to 14 months (mean 8.6 months). The mean value of TBW was normal and directly correlated to body weight, but TBW was abnormally distributed between extracellular and intracellular space. ECW volume was significantly lower than the predicted value (12.1 +/- 1.4 l versus 16.8 +/- 1.9 l) and out of proportion to TBW (34.8 +/- 3.9% versus 47.8 +/- 1.5%). The calculated ICW, therefore, appeared clearly hyperexpanded. The data suggest that cell overhydration was the distinctive feature in our CAPD patients.

Adult↗
PubMed1983

Micro-chromatographic measurement of hemoglobin A1 in uremia.

In an investigation of the reliability of the measurement of HbA1 by microcolumn chromatography for monitoring glucose metabolism in chronic renal failure, measurements were made in 96 uremic patients. Thirty-one patients were undialyzed, 42 patients including 10 with primary diabetes mellitus were on hemodialysis, and 23 patients were on continuous ambulatory peritoneal dialysis (6 with primary diabetes mellitus). Significantly raised HbA1 values were observed in all groups, whether their glucose tolerance was normal or decreased. Azotemia was not statistically correlated either with HbA1 values, or with glucose tolerance. Dialyzed primary diabetic patients showed HbA1 levels which were significantly higher than those in non-diabetics, but some overlap was evident. The results suggest that the increased values of HbA1 in uremic patients depend on the plasma concentration of either glucose which leads to the formation of glycosylated Hb or of urea which leads to the formation of carbamylated Hb. These are indistinguishable by microcolumn chromatography. Therefore this method cannot be recommended for evaluation of glucose metabolism in uremic patients.

Adolescent↗
PubMed1982

Effects of dietary protein and phosphorus restriction on the progression of early renal failure.

Three groups of patients with chronic renal failure were studied. Group 1 comprised 25 patients with a mean serum creatinine of 2.18 mg/dl and a mean arterial pressure of 117 mm Hg. Group 2 had 20 patients with a mean serum creatinine of 4.24 mg/dl and a mean arterial pressure of 119 mm Hg. All these patients were kept for 18 to 76 months on a diet containing about 40 kcal/kg, 0.6 g/kg of protein, 700 mg of phosphorus, and 1,000 to 1,500 mg of calcium (orally supplemented). Group 3 comprised 30 patients with a mean serum creatinine of 2.28 mg/dl and a mean arterial pressure of 116 mm Hg. They had followed no specific dietary regimen for 3 to 72 months, and their dietary calorie, protein, phosphorus, and calcium intakes averaged 35 kcal/kg, 70 g, 900 mg, and 800 mg, respectively. The plots of reciprocal creatinine against time gave slopes of -0.0008 and -0.0010 in patients in groups 1 and 2, and a slope of -0.020 in group 3 patients. The slopes of both groups 1 and 2 were statistically different (analysis of variance and "F" test, P less than 0.01) from that of group 3. No evidence of progressive protein and phosphorus depletion was observed in groups 1 and 2 patients. We conclude that a moderate dietary restriction of protein and phosphorus is an acceptable and effective regimen for delaying progression of functional deterioration in early renal failure.

Adolescent↗
PubMedDate not supplied

A prospective randomised European multicentre study of medium-long run mortality and morbidity comparing acetate-free biofiltration and bicarbonate dialysis.

In recent years, the progressive increase in the mean age of the population entering chronic dialysis treatment has been responsible, on the one hand, for the growing number of patients undergoing regular dialysis, and on the other, for the high number of "critical" patients, both as a result of their age and the presence of concomitant morbidity. Thus, dialysis treatment today is not only aimed at waste removal and water-electrolyte homeostasis, but also at a reduction in morbidity and mortality, and at improving the patients' quality of life, thanks to the use of biocompatible materials and the achievement of good cardiovascular tolerance to treatment. Consequently, diffusive-convective dialysis procedures have been on the increase, since they combine better depuration with the use of biocompatible high-flux membranes. Acetate-free biofiltration (AFB) is a diffusive-convective dialysis procedure which utilises a high-flux membrane, AN69, post-dilution infusion of a sodium bicarbonate solution (NaHCO3), and a dialysate which is completely free of any buffer, and thus also free of acetate, which may have various negative effects on the patient. A number of studies have already shown the better hemodynamic stability and the reduction of intradialytic side-effects during AFB. All these, however, were short-term studies. To verify the beneficial effects of AFB in the long run, a three year multicentre randomised European trial has been proposed to compare bicarbonate hemodialysis (BD), a technique used in nearly 80% of the world's dialysis population, and AFB. The specific aim of the investigation is to verify, in a large number of patients, the results of hemodialysis treatment in terms of morbidity, mortality and quality of life. The study involves 80 hemodialysis units across Italy, France, Germany, Spain, Slovenia and Croatia, with enrollment of about 400 patients considered "critical" for at least one of the following reasons: age, diabetes, dialysis cardiovascular instability. Fifty percent of the patients are to undergo AFB with the AN69 membrane and bicarbonate solution infusion (NaHCO3 145 or 167 mEq/lt), and the other fifty percent are to be treated by BD, with any membrane except the nonmodified cellulosic one. Biochemical, cardiological, and nutritional parameters will be considered throughout the study. Mortality, morbidity both in terms of intra- and interdialysis symptoms - and hospitalisation rate, as well as the patients' quality of life, evaluated by the SF36 questionnaire, will be analysed.

Aged↗
PubMedDate not supplied

[Case report: reversible acute renal failure following therapy with both ketorolac (non-selective non-steroidal anti-inflammatory drug NSAID) and celecoxib (COX-2 selective) in the same patient].

BACKGROUND: We present the case of acute renal failure complicating the course of therapy with both ketorolac (non-selective Non-Steroidal Anti-inflammatory Drug, NSAID), and celecoxib (COX-2 Selective Inhibitor) in an elderly woman with chronic liver disease, heart failure and chronic renal failure. The main effect of NSAIDs is the inhibition of cyclooxygenase (COX), the enzyme involved in prostaglandins synthesis. The nephrotoxicity of NSAIDs is linked to this effect since prostaglandins not only act in response to inflammatory stimuli, but also play a role as modulators of some physiological renal functions. Under conditions of reduced renal perfusion, acute renal failure secondary to NSAIDs use may occur if the vasoconstrictive forces stimulated to maintain the filtrating function are not balanced by prostaglandin-induced vasodilatation. About ten years ago, two COX isoforms were demonstrated: COX-1 whose products are involved in regulating physiological functions and COX-2 which is expressed by a number of inflammatory stimuli. The discovery of molecular differences between COX-1 and COX-2 allowed the development of pharmacological agents selectively inhibiting COX-1 or COX-2. Selective inhibitors of COX-2 are now available. However, COX-1 products are involved in inflammatory reactions, whereas COX-2 products play a physiological role in many tissues and organs, including the kidney. These observations raised many doubts regarding the renal safety of COX-2 Inhibitors before they became commercially available. These doubts have been recently confirmed in the Literature. CONCLUSIONS: The case we report seems to confirm that, in patients at risk, the renal adverse effects of non-selective NSAIDs and of COX-2 Inhibitors could be the same due to the similar physiological role of COX-1 and COX-2-dependent prostaglandins.

Acute Kidney Injury↗
PubMedDate not supplied

[Thermal energy balance during hemodialysis: the role of the filter membrane].

BACKGROUND: Body temperature tends to increase during conventional haemodialysis; this might interfere with normal cardiovascular response to dialytic ultrafiltration, thus facilitating the occurrence of symptomatic hypotension. Putative factors responsible for changes in thermal balance during haemodialysis include heat load from the dialysis bath, reduction in convective heat loss secondary to skin vessel vasoconstriction, heat overproduction due to central stimulation by bioincompatibility reactions to the filter membranes. The aim of the present study was twofold: to define thermal energy balance (ET) during dialysis and to investigate the effect of membrane bioincompatibility on energy balance METHODS: We measured ET in 12 patients (9M, 3F) during two identical dialysis sessions, differing only in the membrane composition of the filters used: cuprophane 1.3- 1.6 mq and LF polysulphone 1.3- 1.6 mq. Thermal energy balance studies were performed by the Blood Temperature Monitor (Fresenius Medical Care) under conditions in which the core temperature of the patients was maintained unchanged from the start to the end of the dialysis procedure. RESULTS: Arterial blood temperatures were constant, while dialysate and venous blood temperatures progressively decreased (from 36.9 to 35.4 C and from 36.5 to 35.1 C for cuprophane; from 36.9 to 35.2 and from 36.9 to 35.1 for polysulphone membrane). Mean thermal energy transfer was negative (removal of energy from the patients to the extracorporeal circuit) with both filters, equal to 146 KJ with cuprophane and to 163 KJ with polysulphone. When a stepwise multiregression analysis was applied, hourly energy transfer (ET) was significantly and independently correlated with both ultrafiltration rate (UF=% b.w.) and heart rate changes (HR) according to the equation: ET= -92.03+41.29 UF+1.04 HR (p<0.0003). Conclusions. In this study we present experimental evidence that increased body temperature during dialysis is not caused by heat load from the dialysis bath, nor by heat over production secondary to bioincompatibility reactions. Consequently, haemodynamic responses to dialytic ultrafiltration may be regarded as the main regulatory factor of thermal balance.

Aged↗