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Biomedical subjects

S Biasioli

Publications and source records attributed to S Biasioli.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1984

The role of neurotransmitters in the genesis of uremic encephalopathy.

To classify the influence of neurotransmitters in the genesis of uremic encephalopathy we studied cerebrospinal fluid (CSF) and plasma (P) amino acid (AA) concentration, in patients undergoing various dialytic treatments (hemodialysis = HD, intermittent and continuous peritoneal dialysis = IPD and CAPD). HD causes a significant decrease in CSF/P ratios of branched chain AA (BCAA) and a significant increase in CSF Glycine/Valine ratio, suggesting an augmented brain uptake of Glycine at detriment of Valine. In IPD the general trend of Aromatic AA/BCAA ratio suggests a preferential transport of Aromatic AA through the blood brain barrier. The differences between IPD and HD are confirmed by data concerning metabolites of Serotonin and Dopamine: CSF concentrations of 5- Hydroxyindoleacetic acid and Homovanillic acid are low in HD but high in IPD. So, a reduced (in HD) and an increased (in IPD) activity of monoamine systems could be at the basis of some neurological disturbances appearing in uremia.

Adolescent↗
PubMed1982

Changes of cerebral density in dialyzed patients.

CT studies were made on 38 patients receiving different dialytic treatment, 10 patients with chronic renal failure not yet dialyzed, and 15 healthy subjects. No morphological modifications were observed. On the contrary, significant changes of density were demonstrated after a dialysis session in the population treated intermittently. In these patients the density values were similar to those registered in the controls 1-6 h after a dialysis session. End stage renal failure and CAPD patients always had normal density values. Therefore cerebral density changes are caused only by the intermittent dialytic treatment.

Absorptiometry, Photon↗
PubMed1982

Studies on brain density in hemodialysis and peritoneal dialysis.

30 patients on hemodialysis or peritoneal dialysis have been investigated by computerized tomographic (CT) scan. To evaluate possible cerebral alterations induced by dialysis, CT examinations were carried out before, immediately after and 6 h after the end of dialysis with an Evaluskop, which provides an objective precise evaluation of even slight variations in brain density. No morphological variations were noted after dialysis, while the brain density fell significantly during and after the treatment. A decrease in density was not observed in normal subjects or in patients on continuous peritoneal dialysis. The changes in the densitometric values of brain tissue suggest that there is a postdialysis gain in cerebral water linked to the intermittent treatment. CT may represent a simple reliable method for studying uremic encephalopathy and investigating the pathogenesis of the dialysis disequilibrium syndrome.

Adolescent↗
PubMed1982

Anatomical bases of peritoneal permeability: a reappraisal. Anatomy of peritoneum.

The peritoneal membrane consists of flat mesothelial cells linked together with digitations and containing vesiculae with pinocytic capacity, of endothelial cells (containing Weibel-Palade's bodies and vesiculae) and of an interstitial tissue consisting of a network of watery channels. The cellular structures of mesothelium and endothelium are characterized by tight and gap junctions or perhaps by macular junctions. The visceral peritoneum shows a prevalence of gap junctions, the pericysic veins contain only tight junctions while both types can be found in the arterioles. Two different ways for solute transport are theoretically possible: the vesicles of plasmalemma (via pinocytosis) and the junctions (via size-sieving effect). Studies with tracers did not furnish unequivocal data on this problem and did not clarify if these structures could be the equivalent of the pores of the Landis-Pappenheimer's theory. The studies of Karnowsky and Simionescu, using tracers, have in fact given opposite results.

Animals↗