PubMed Health⌕ Search

Biomedical subjects

R Maiorca

Publications and source records attributed to R Maiorca.

At least 109 records · Page 6Linked to original sources
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

Prospective controlled trial of a Y-connector and disinfectant to prevent peritonitis in continuous ambulatory peritoneal dialysis.

A controlled study in two centres compared the efficacy of the standard continuous ambulatory peritoneal dialysis (CAPD) system with that of a new method consisting of a Y-shaped set filled with sodium hypochlorite during the dwelling time. 62 new CAPD patients were randomly allocated to the standard method (group A: 30 patients; age 55.5 +/- 17.5 years) or to the Y-system (group B: 32 patients; age 55.1 +/- 14.3 years). In group A, there were 31 peritonitis episodes in 17 patients (57%) during a cumulative period of 351 months--1 episode every 11.3 patient-months. In group B, there were 11 peritonitis episodes in 10 patients (31%) during 363 months--1 episode every 33 patient-months. Life-table analysis showed a significant difference between the incidence of peritonitis in the two groups. The Y-system method is simple and economical and the frequency and the severity of side-effects appears to be acceptable.

Adolescent↗
PubMed1983

Effects of light saline loading on renal renin and catecholamine release in hypertensive humans.

In 8 essential hypertensive patients infusion of 7.5 ml kg-1 b.w. of isotonic saline over 20 min decreased plasma renin activity but did not affect plasma adrenaline or noradrenaline concentrations in suprarenal aortic, renal venous and caval blood. Mean blood pressures and heart rates were unchanged throughout the saline infusion period, whereas the hematocrit was significantly decreased. These data suggest that inhibition of renin secretion after slight volume expansion with saline in hypertensive humans occurs without parallel inhibition of either renal neurosympathetic drive or humoral adrenergic tone to the kidney through circulating catecholamines.

Adult↗
PubMed1983

'Y' connector system for prevention of peritonitis in CAPD: a controlled study.

To compare the efficacy of the standard Oreopoulos CAPD system with that of a new method consisting of a Y-shaped set filled with sodium hypochlorite during the dwelling time, a randomised controlled study was performed in 62 new CAPD patients. Life table analysis showed a significantly (p less than 0.001) less frequent incidence of peritonitis in the group treated with the Y connector system. This study shows that the Y system appears to be effective in reducing the incidence of peritonitis, as compared with the standard technique, in patients on the CAPD programme. The method is simple and economical and the incidence and the severity of side effects appear to be acceptable.

Adolescent↗
PubMed1982

[Effect of pretreatment with atenolol and propranolol on sympatho-adrenal and cardiovascular responses to acute insulin-induced hypoglycaemia in the hypertensive patient].

Plasma catecholamines and cardiovascular responses to acute insulin i.v. injection (0.12 U.I. per Kg of body weight) have been studied in eight patients with mild essential hypertension. The hypoglycaemia test was carried out before and after a week of atenolol treatment. In six patients the test was also repeated after propranolol treatment. Following insulin injection, blood sugar fell abruptly with a nadir at 30 m, diastolic blood pressure decreased, and systolic blood pressure and heart rate rose significantly. Atenolol treatment abolished almost completely these hemodynamic changes. By contrast, propranolol caused an increase in both systolic and diastolic blood pressures, leaving the heart rate unmodified. During hypoglycaemia, plasma adrenaline rose sharply in coincidence with the glycaemic nadir and declined thereafter during the glycaemic recovery. Plasma noradrenaline rose less markedly than adrenaline, but the increments were significant after 30 and 60 m. Neither atenolol, nor propranolol affected significantly these changes in plasma catecholamine concentration. These data indicate that beta-blockers do not alter the hypoglycaemia-induced adrenomedullary release of catecholamines. We conclude therefore that beta-blockers modify the pattern of the hemodynamic response to acute hypoglycaemia by interfering with the peripheral effects of circulating catecholamines in a way which depends on the degree of beta-1 selectivity of the drug used.

Adult↗
PubMed1982

Interrelationships between blood pressure, blood gases and plasma acetate concentrations during conventional hemodialysis.

To determine to what extent the intradialysis changes in blood pressure (BP) are related to the variations in blood gases and plasma acetate concentrations (plAc), 11 dialysed uremics were studied with measurement of plAc,pH, pCO2 and pO2 every 60' during a hemodialysis lasting 4 hrs. Dialysis resulted in significant decreases in the BP, pO2 and pCO2 and in significant increases in pH and plAc. Multiple regression analysis demonstrated that the delta % for the mean BP was closely related to plAc, pCO2 and delta-% of body weight (BW). Partial regression coefficient indicated the following rank order of correlation: plAc greater than pCO2 greater than or equal to delta-% BW greater than pO2 = O, thus demonstrating that the fall in blood pressure is related both to the increase in plAc and the decrease in pCO2. The physiological relevance of these relationships is discussed. The hypothesis is advanced that the pCO2 decrease during dialysis might contribute to the acetate-induced vascular instability.

Acetates↗
PubMed1981

Plasma catecholamine response to postural stimulation in normotensive and dialysis hypotension-prone uremic patients.

The neurosympathetic responsiveness of two groups of uremics, each group treated for the same mean time by dialysis, categorized as normotensive, mean age 28.3 +/- (SE) 3 years, or dialysis hypotension-prone, mean age 49.6 +/- 5 years, was studied by determining plasma norepinephrine and epinephrine before and after postural activation of the sympathetic reflex arc. The study was performed on an interdialysis day and repeated 20 min before and after a regular dialysis on the following day. Standing caused norepinephrine to rise significantly in both the normotensive and the hypotension-prone groups and to a similar extent as in a control nonuremic group. Blood pressure did not change and the heart rate increased significantly. Plasma norepinephrine before dialysis 24 h later behaved in the same way, but both blood pressure and heart rate were unchanged. After dialysis, in spite of the usual increase in norepinephrine after standing, patients in the hypotension-prone group became hypotensive. These results suggest that there is a normal sympathetic responsiveness in uremics whatever their propensity for intradialysis hypotension. Moreover, dialysis does not seem to have an acute effect on the neurosympathetic response to a hypotensive stimulus. Dialysis-dependent hypotension, which appears to be more frequent in older subjects, probably reflects an impairment of the vasoconstrictor response of the vascular wall acutely induced by dialysis itself.

Adolescent↗
PubMed1977

Blood pressure control in end-stage renal disease in man: indirect evidence of a complex pathogenic mechanism besides renin or blood volume.

1. In twenty-three uraemic patients on regular dialysis, plasma renin activity and blood volume were measured before and after a single dialysis. Three groups were identified; the first had a low or normal plasma renin activity and a high or normal blood volume, the second had a high plasma renin activity and a low blood volume and the third had both variables above normal. 2. In spite of these differences, diastolic blood pressure before and after dialysis was the same in the three groups and multiple regression analyses failed to demonstrate any dependence of blood pressure on plasma renin activity, blood volume or body weight taken separately or together. 3. We conclude that other factors besides plasma renin activity and blood volume are important in maintaining arterial hypertension in terminal renal failure.

Adult↗
PubMed1975

[Physiopathology of proteinuria and of renal regulation of the metabolism of circulating proteins].

The glomerular filtration of circulating proteins takes place at the level of the slit membrane where a porous structure, which limits or halts the passage of protein molecules of medium size, has been singled out. The small proteins, and among them many proteic hormones, are filtered, reabsorbed, and, to a great extent, catabolized by the tubular epithelia by means of at least partly selective mechanisms. Besides producing proteinuria, glomerular hyperpermeability, which does not modify the metabolism of microproteins, exposes to tubular catabolism a non-measurable quota of medium-sized nolecules whose survival in circulation is thus abbreviated. Reduced glomerular permeability does not influence the metabolism of medium-sized molecules, but reduces the catabolism of microproteins which are retained in the blood, a fact which is biologically very important. The clinical consequences of this retention have not yet been investigated.

Blood Proteins↗
PubMed1975

Short time personalised dialysis: good results in spite of high levels of small and middle molecules.

After almost two years of experience with 43 patients we believe that a short (3 X 4, 3 X 3 hr/week) personalised dialysis is a safe treatment that allows a high survival rate and a good rehabilitation of patients. Pre-dialysis levels of small and middle molecules, the latter only calculated, did not correlate with 5 typical uraemic parameters. Some patients, who formerly experienced standard dialysis, are now equally well or better, without evidence of increasing toxicity, in spite of their higher pre-dialysis levels of small and especially of middle molecules.

Adult↗