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Biomedical subjects

G Bellinghieri

Publications and source records attributed to G Bellinghieri.

18 recordsLinked to original sources

The course of autonomic neural function in chronic uraemic patients during haemodialysis treatment.

Autonomic function was followed in 19 patients with uraemia on chronic haemodialysis treatment over a period of 18 months. A smaller group of 12 patients were studied over 56 months. The battery of cardiovascular reflex tests included R-R interval variation test, deep breathing, Valsalva manoeuvre, heart rate, and blood pressure responses to standing and sustained handgrip. Two indices of autonomic function were measured: the autonomic score, and the confidence level on Bayesian analysis. There was great variability in the course of autonomic function over the period studied, with improvement occurring in some subjects and deterioration in others. In addition some patients did not develop any abnormality. Among those patients with uraemia and normal autonomic function at the start of the study, a deterioration occurred in 33-36% in the 18-month follow-up but in 62.5% in the 56-month follow-up. As a group there was no significant change in autonomic function during follow-up, although a clear trend to deterioration was found despite chronic haemodialysis treatment.

Adult

The coagulative system in haemodialyzed patients: the relationship between the elderly and hypertrygliceridaemia.

The coagulative system has an important role on haemodialysis and on atherosclerosis genesis; in particular the platelets are key elements of the coagulation and of atherosclerosis phenomena. Alterations of the coagulative system and increase risk of developing atherosclerosis are reported in the aging. We in this paper, report the results obtained studying the influence of the interaction between the elderly and dyslipidemia on the coagulative system in haemodialyzed patients. The obtained data showed that the hypertriglyceridaemia in interaction with the elderly accelerates and increases platelet aggregation after stimulation by ADP, Epinephrine and Collagen. So, it is important to consider hypertriglyceridaemia and age as thrombogenic factors and atherosclerosis accelerating factors in haemodialyzed patients.

Adenosine Diphosphate

[Dyslipidemia in the uremic patient: the therapeutic role played by simvastatin].

Simvastatin is a pharmacological molecule belonging to the family of HMG-CoA reductase inhibitors, recently included in plasma cholesterol lowering therapy. The authors carried out a study on the possible triglyceride lowering activity of simvastatin in dialyzed patients with chronic uremia considering its particular mechanism of action. The subjects selected for the study were suffering from uremia either complied with dosage prescribed or not. The obtained data showed the substance's triglyceride lowering effect, but no simvastatin-related side effect in the dialysed patients with uremia. For these reasons and for the substance's well-known cholesterol-lowering effect, simvastatin seems to deserve the definition of choice drug in the treatment of altered lipidemia in patients with uremia.

Aged

[The hypotriglyceridemic action of the combination of L-carnitine + simvastatin vs. L-carnitine and vs. simvastatin].

Previous studies had determined the role played by L-carnitine and simvastatin in the treatment of altered lipidemia in dialyzed patients with chronic uremia. The authors carried out a study on the above substances either singly or together administered to the same patients with chronic uremia in hemodialysis. This study was aimed at demonstrating the possible synergic normolipidemic action of both substances in comparison with their single administration, because their different mechanism of action could be metabolically enhanced. The obtained results demonstrated that the therapeutic association proposed is preferable to the use of the single substances. Moreover, a higher and more rapid normolipidemic effect was obtained after using L-carnitina associated with simvastatin with respect to the separated substances.

Aged

Uremic autonomic dysfunction evaluated by pattern recognition analysis.

A pattern recognition analysis of six cardiovascular reflex tests was performed with the aim to increase their diagnostic efficiency. A normal model was defined by SIMCA method using log-transformed values of 85 healthy subjects. The model was tested with data from 60 patients with chronic renal failure. Specificity resulted 94% and sensitivity 96%. 55% of the uremics were recognized affected by autonomic damage. The method allowed a better definition of autonomic function in those patients defined as "borderline" on conventional evaluation of the tests. Pattern recognition analysis of autonomic tests provides a global assessment of all the tests performed. Its use should be encouraged as a diagnostic tool.

Autonomic Nervous System Diseases

Evidence for Raynaud's syndrome among haemodialyzed patients: influence of flunarizine treatment.

A bloodless study with a Photoplethysmographic test of the limb's blood circulation among haemodialyzed patients with arteriovenous fistula and the influence of Flunarizine treatment was performed. All patients showed a blood reduction flux on the hand with fistulas in front of the controlateral limb. Three patients affected by Raynaud Syndrome were identified. The Flunarizine treatment did not show significative blood flux variations among among those patients with low Photopletysmographic index (P.I.) in the limb with arteriovenous fistula, while a significative increase of P.I. was registered in the limb of the patients affected by Raynaud Syndrome. Concluding, the Photopletysmographic test is useful to follow the limb's blood circulation of haemodialyzed with arterio-venous fistula, being it bloodless, sure and repeteable test to follow the influence of vasoactive therapy.

Adult

Uraemic autonomic neuropathy.

Symptoms of uraemic autonomic neuropathy are often vague and aspecific. A correct diagnosis of autonomic dysfunction is possible by using several simple and non-invasive tests of parasympathetic and sympathetic control of the cardiovascular system. A defective regulation of the heart rate, due mostly to an afferent lesion, is more common than damage of reflex blood pressure control. The former appears isolated in 14 to 34% of uraemics on haemodialysis and combined to the latter in 18 to 26%. Contradictory results are reported about influence of intermittent haemodialysis, continuous ambulatory peritoneal dialysis and kidney transplantation on disturbed autonomic nervous system. Pathogenesis of uraemic autonomic neuropathy remains unknown and some mechanisms are only putative.

Autonomic Nervous System

L-carnitine and platelet aggregation in uremic patients subjected to hemodialysis.

It has been reported that treatment with L-carnitine at a daily dose of 3 g orally may cause a rise in platelet aggregation and serum triglyceride concentration in hemodialyzed patients. The present double-blind cross-over study has been performed to evaluate the influence of L-carnitine when compared with placebo on platelet aggregation and plasma concentrations of various factors involved in platelet activation. In addition, the concentration of triglycerides, cholesterol and HDL-cholesterol has been evaluated. 18 uremic patients on maintenance hemodialysis for at least 1 year were randomly allocated either to a control group receiving placebo or to a group treated with L-carnitine. Statistical analysis performed by means of ANOVA did not show any significant change in the serum concentration of cholesterol, HDL-cholesterol and triglycerides. Furthermore, platelet aggregation tests (performed with adenosine 5'-diphosphate, epinephrine, thrombin and collagen) and plasma beta-thromboglobulin concentration did not show any statistically significant difference. In addition, the plasma concentration of several coagulation markers, such as factor VIIIc, antithrombin III, alpha 2-antiplasmin, and fibrinopeptide A, did not show any significant variation. The results suggest that under our experimental conditions L-carnitine neither increases the risk of thromboembolism nor alters the serum lipid content in uremic patients on chronic hemodialysis.

Adult

Comparative analysis of autonomic and somatic dysfunction in chronic uraemia.

The relationship between autonomic dysfunction and peripheral somatic neuropathy was investigated in uraemics. The battery of autonomic tests included R-R interval variation test, deep breathing, Valsalva manoeuvre, heart rate and blood pressure responses to standing, and sustained handgrip. Maximum conduction velocity along sensory and motor fibres of the posterior tibial nerve was measured. An impairment of parasympathetic reflexes was more frequent than a sympathetic damage, but with no relationship to the degree of electrophysiological disturbances. Cardiovascular autonomic dysfunction and somatic neuropathy in uraemia result to be two different entities in incidence and perhaps in pathogenesis.

Adult

Occurrence of uraemic autonomic dysfunction in relation to age.

A battery of cardiovascular reflex tests were performed on 20 patients with chronic renal failure on intermittent haemodialysis, to assess occurrence of parasympathetic and sympathetic abnormalities. Using age-adjusted confidence limits, elderly uraemics showed more extensive parasympathetic and sympathetic dysfunction than middle-aged patients. The results suggest that the autonomic nervous system in the elderly is more susceptible to uraemic toxins than in the middle aged. This should lead to better preventive and therapeutic strategies for older uraemics.

Adult

[Regulation of the renin-angiotensin-aldosterone system. Role of the prostaglandins].

PRA (in the supine and erect subject) and urinary sodium before and after acute treatment (100 mg i.m.) and chronic treatment (100 mg per os for 8 days) were examined in two groups of subjects with no signs of cardiovascular or renal disease. It was found that indomethacin, which is a well-known inhibitor of prostaglandin synthesis, reduced PRA levels in basal conditions and as a result of postural stimulation, without causing any appreciable change in urinary sodium. Regulation of the PRA on the part of the renal prostaglandins is postulated and its probable mechanisms discussed.

Adrenal Cortex

Autonomic nervous system dysfunction in chronic uraemics on haemodialysis.

A battery of cardiovascular reflex tests were performed in 35 patients with chronic renal failure on intermittent haemodialysis. An impairment of parasympathetic control was found isolated (14%) or combined with a damage of sympathetic control of cardiovascular system (26%). Moreover, maximum conduction velocity along sensory and motor fibres of posterior tibial nerve was measured in 21 patients. Autonomic dysfunction and somatic neuropathy did not appear strictly related.

Adult

Age-dependent occurrence of autonomic dysfunction in chronic uraemia.

A battery of cardiovascular reflex tests were performed in twenty patients with chronic renal failure on intermittent haemodialysis. Using age-adjusted confidence limits, old-aged uraemics showed more extensive parasympathetic and sympathetic dysfunction than middle-aged patients. The results suggest that autonomic nervous system in the elderly is more susceptible to uraemic toxins than in the middle age. This should lead to better preventive and therapeutic strategies in older uraemics.

Adult

Uremic vagal neuropathy: has parathyroid hormone a pathogenetic role?

Cardiac vagal reflexes were investigated in 19 dialysis patients, with the aim of verifying whether parathyroid hormone, proposed as an important uremic neurotoxin, plays a role in the development of uremic vagal neuropathy. The results indicate that parasympathetic control of heart function is frequently impaired in uremics. Plasma parathyroid hormone levels were significantly correlated with the time on dialysis. However, a correlation between autonomic disturbances and plasma parathyroid hormone concentrations was not found in this study.

Adult