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Biomedical subjects

S Biasioli

Publications and source records attributed to S Biasioli.

At least 19 recordsLinked to original sources
PubMed1992

[Is it possible to improve the nutritional status of dialysis patients?].

It is well known that hemodialyzed patients show a protein-calorie malnutrition (PCM) due to several factors: dialytic and/or biologic age, diet, hormonal status, amino acid loss. The nutritional status of 44 HD patients was quarterly evaluated from september '87 to may '90 (32 months) and ten of them (5 M, 5 F) were treated by means of L-carnitine (6 g/ev/week) from september '88 to may '90. In the 5 treated males a net gain (+ 80 g/month) of the muscle mass was observed while the 5 treated females showed a low increase of fats. This trend was different (even though not significantly different) from that observed in the untreated group, in which a muscle mass loss and a fat increase was the rule.

Aged↗
PubMed1991

Effect of dialysate and substitution fluid buffer on buffer flux in hemodiafiltration.

The effect of differing dialysate and substitution fluid buffer types and concentrations on acid-base balance have not been assessed in patients treated with hemodiafiltration for ESRD. To determine bicarbonate, acetate, lactate and total buffer flux, mass balance studies were performed in patients treated with hemodiafiltration using four different combinations of dialysate and substitution fluids. Driving force for bicarbonate flux was assessed in all treatments. Bicarbonate flux depended on bicarbonate driving force and ultrafiltration rate. Bicarbonate flux was negative in all treatment combinations, even when the driving force was positive. Acetate flux was positive in all treatment combinations, but the net magnitude was small. Lactate flux, when lactate containing substitution fluid was used, varied with dialysate buffer employed during treatment. Overall buffer flux depended on the bicarbonate driving force, ultrafiltration rate, and varied with the type of substitution and dialysate buffer employed. The types and concentrations of buffer used in dialysate and substitution fluid have important effects on the acid-base balance of patients treated with hemodiafiltration. The long-term implications of different therapeutical choices in these patients is unknown.

Acetates↗
PubMed1990

[Clinical evaluation of 2 years of hemodiafiltration using bicarbonate].

At the end of a previous study concerning the use of different buffers for hemodiafiltration (BHDF) in both the re-infusate (40 mM/L) and dialysate (26 mM/L). Retrospective data analysis and showed BHDF to permit good acid/base balance, good clinical tolerability and satisfactory and persistent sense of well-being. From the point of view of kinetics, it is essential to evaluate carefully the acute and/or chronic effect of an alkaline blood pH during or after dial lysis, especially since the volume distribution of bicarbonate is not known.

Bicarbonates↗
PubMed1990

Cardiovascular stability during the haemodialysis session: relationship between modelling and impedance parameters.

The percentage of body water, if calculated from impedance, was found to be significantly different from the classic 58%. This supports the view that the evaluation of the dialytic efficiency should be, in the near future, carried out on the basis of a 'two-pool' model instead of the old 'one-pool'. The serial collection of data during a dialytic session supported the hypothesis that, 90 min after the start or, in general, after a body-water loss of about 5%-6%, some fundamental changes in measured indexes (phase angle, systolic pressure, body volumes, correlation matrix) usually appear. Large-scale research, based on an RS 232 interface connected to a computerised program, will probably help in clarifying whether some major intra-dialytic phenomena could in the near future be easily and automatically predicted.

Body Water↗
PubMed1989

Acid base correction in bicarbonate CAPD patients.

Bicarbonate has been proposed as buffer in CAPD solutions in recent years instead of lactate and acetate. The present study is designed to evaluate peritoneal bicarbonate kinetics using bicarbonate solutions. Seventy kinetic studies have been performed in 7 patients treated with 2 CAPD solutions containing 35 mmol/l (A) and 27 mmol/l (B) of bicarbonate. The changes in dialysate bicarbonate concentration at different dwell times were correlated with bicarbonate blood levels. Furthermore after 2 hours of dwell time and at subsequent observations, no differences in dialysate bicarbonate concentration were found between A and B solutions at the same bicarbonatemia. Thus a feedback between bicarbonate absorption and bicarbonate blood concentration was observed. If the amount of bicarbonate transferred to the patient is over the metabolic acid production, bicarbonatemia will rise: consequently bicarbonate dialysate absorption will decrease. After a few days, an equilibrium point will be reached. In this condition the bicarbonate absorption is equal to metabolic acid production and, in stable clinical conditions, a stable acid base status will be maintained by the patient. Our studies empirically demonstrated that the equilibrium is reached when a difference of 5 mmols between blood and inlet dialysate bicarbonate concentration is observed. Consequently to achieve 25 mmol/l of bicarbonatemia, the bicarbonate concentration of CAPD solution should be about 30 mmol/l.

Acetates↗
PubMed1989

Different buffers for hemodiafiltration: a controlled study.

Hemodiafiltration (HDF) is usually performed using a dialytic solution (D) containing acetate (A) or bicarbonate (B) and a replacement fluid (RF) containing lactate (L). To clarify the role of buffers in HDF, 11 patients underwent different study periods, each three months long: bicarbonate hemodialysis (BHD = Baseline period); HDF with (A) in D and (L) in RF (first period of HDF); HDF with (A) in D and (B) in RF (second HDF); HDF with (B) in D and (L) in RF (third HDF); HDF with (B) in D and (B) in RF (fourth HDF = BHDF). HDF achieved: 1) an increase in dialytic efficiency (kt/V, 1.28), reducing the time-session (197 min); 2) an improvement in acid-base status (pre-dialytic values in BHDF: pH 7.36; pCO2 39.8 mmHg; HCO3- 21.8 mM/L); 3) better "dry weight" gain (reached in 92.8% of HDF and in 81% of BHD sessions); 4) a significant decrease, in dialytic side-effects (mainly during the third and fourth periods). On the whole, BHDF (HDF done using only bicarbonate buffer) represents an easy and safe technique, leading to better cardiovascular stability than BHD and HDF without bicarbonate buffer.

Acetates↗
PubMed1988

High-flux haemodialysis with 1.5 m2 modified cuprammonium rayon membrane: technical and clinical evaluation.

The feasibility and reliability of a short dialysis technique performed with standard dialysis equipment and a modified cuprammonium rayon hollow-fibre filter has been studied. The hydraulic response of the filter and membrane to high blood flows and transmembrane pressures were tested in vitro and the maximal clearances of different solutes achievable during high-flux bicarbonate dialysis were studied in vivo. Clinical studies were undertaken to evaluate the long-term effects of the short, highly efficient dialysis therapy. Six patients were treated for more than a year with single-pass bicarbonate dialysis with a blood flow of 500 ml/min, dialysate flow of 700 ml/min, and average duration of 150 min/session three times weekly. The treatment showed an adequate efficiency with an average KT/V greater than 1. All patients obtained an average blood urea nitrogen during the study of less than 80 mg/dl and an average protein catabolic rate of 0.9 g/kg per 24 h. The treatment was well tolerated by all patients and, on echocardiography, no significant changes in myocardial function were detected after one year of therapy. The treatment is efficient, well tolerated, simple to monitor and does not require the use of synthetic membranes or machines with advanced technology. Thus the reduction of dialysis treatment time is feasible in all centres at a relatively low cost.

Adult↗
PubMed1988

Chronobiological variations of prolactin (PRL) in chronic renal failure (CRF).

During a 24-hour period, the serum levels of prolactin (PRL) were determined in 89 subjects, including 24 controls and 65 with chronic renal failure (CRF), divided into groups according to sex, age and serum creatinine. In mild CRF, both in males and females, PRL level proved to be higher than controls while its circadian rhythm of secretion disappeared. The MANOVA analysis (multivariate analysis of variance) showed that all 3 considered factors (sex, age, creatinine) have a systematic effect on PRL values, that of creatinine being the most prominent. With the progression of renal failure, the physiological PRL oscillations tended to diminish. In general, increasing creatinine levels progressively shifted the acrophase (that is the time-distance between a given hour and the maximum peak of the function) to the morning, with hemodialysis patients showing acrophases between 12 p.m. and 1 a.m. It is possible that in CRF the PRL feedback system could no longer function.

Adolescent↗
PubMed1987

Hyperprolactinemia as a marker of neurotransmitter imbalance in uremic population.

Serum prolactin (PRL) levels are elevated in patients with chronic renal failure (CRF) but the mechanisms responsible for these abnormalities are not fully understood. PRL secretion is undoubtedly influenced by many substances, which can be variously altered in uremia: monoamines, endogenous opiates and PTH. Our data suggest that in early renal failure PRL levels are already significantly high and the 24-h pattern of PRL secretion is significantly different from that in controls. PRL derangements could be due in mild renal failure, to unknown factors (GABA?); in severe CRF, to a major change in dopaminergic activity; in hemodialysis (HD), to a low turnover of monoamines, and in peritoneal dialysis (PD) to increased activity of serotoninergic and dopaminergic systems.

Adolescent↗
PubMed1987

Tricarboxylic acid cycle intermediates in chronic renal failure.

In 21 uraemic subjects not yet requiring dialysis, the serum values of citrate, fumarate, oxalacetate and malate were significantly increased, so that the sum of the concentrations of the TCA-cycle intermediates were increased threefold compared to that of 18 control subjects. The replenishment of TCA intermediates could, in theory, occur by several anaplerotic reactions, mainly those catalysed by pyruvate-carboxylase and malic enzyme. The overall pattern detected in uraemic patients is similar to that observed in rat skeletal muscle during exercise, in which increased acetyl CoA has been found.

Adult↗
PubMed1986

Buffer kinetics in biofiltration.

A condition of metabolic alkalosis has been generally observed in patients undergoing regular biofiltration (BF). The aim of this study was to assess buffer kinetics during a dialysis session in five patients regularly treated by BF for 10 months (dialyzer Biospal 3000S, Qb 301; Qd 545; UF 36.76 ml/min; dialysate CH3 COO 38 mEq/L; replacement fluid 1000 ml/h with HCO3 100 mEq/L solution). As usually happens using dialyzers with high surface area and permeability, large HCO3 losses (756 +/- 112 mEq) and CH3COO uptakes (677 +/- 152 mEq) were observed. Acetate plasma levels rose to 10.4 mEq/L, a value potentially dangerous to the cardiovascular system. The dialytic buffer gain (acetate uptake + HCO3 administered - HCO3 loss) was high (230 +/- 137 mEq/dialysis) and excessive for patients' needs. It is therefore very important to reduce either the acetate concentration in dialysate or the amount of reinfused bicarbonate. In view of the plasma acetate levels it is preferable to use a dialysis solution containing less acetate.

Acetates↗
PubMed1986

Uremic encephalopathy: an updating.

Uremic encephalopathy (UE) is a clinical syndrome, closely linked to the progression of renal failure. Many approaches can be utilized to diagnose it: EEG changes, somatosensory evoked potentials, choice reaction time test, cerebrospinal fluid (CSF) studies, brain computerized tomography, plasma and CSF amino acid concentration. On the basis of the data available at present, it is possible to postulate that UE could be caused by amino acid derangements (mainly glutamine, glycine, aromatic and branched-chain amino acids) and by the subsequent imbalance of neurotransmitters (mainly GABA, dopamine, serotonin). Disturbances of mental, neurologic, motor and hormonal functions could derive.

Amino Acids↗