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Biomedical subjects

R Maiorca

Publications and source records attributed to R Maiorca.

At least 91 records · Page 5Linked to original sources
PubMed1988

Effects of changes in intravascular volume on atrial size and plasma levels of immunoreactive atrial natriuretic peptide in uremic man.

To study the trigger for the release of atrial natriuretic peptide (ANP) in man, we measured the atrial areas (AA) by 2-D echocardiography, the total blood volume (TBV) by 131I-serum albumin and plasma immunoreactive ANP (i-ANP) concentrations by radioimmunoassay, after prior plasma extraction, for 10 dialyzed uremic patients. Measurements were made when the patients were volume-loaded or volume-depleted by isoosmotic ultrafiltration and again 48 h later, when they were again volume-loaded. Analysis of plasma extracts by high-performance gel permeation chromatography revealed that the greatest amount of the i-ANP fraction was a peptide eluting like human synthetic alpha-ANP. Ultrafiltration consistently decreased the TBV, while spontaneous regain of body-fluids caused TBV to rise to pre-ultrafiltration levels. Changes in TBV were closely related in time to changes in both right (RAA) and left (LAA) atrial area and in plasma i-ANP concentrations. Significant direct relationships were found between TBV and RAA, TBV and i-ANP and between both LAA and RAA and i-ANP. Furthermore, the decreases and the increases in TBV, RAA and LAA were closely correlated with changes in i-ANP. Multiple regression analysis, however, revealed that the changes in plasma i-ANP were mainly related to the changes in RAA, with little or no relationship to the changes in TBV or LAA. These findings are evidence for a positive feed-back between the level of intravascular filing volume, extent of atrial distention and amount of i-ANP released into the blood stream.

Adult↗
PubMed1988

CAPD is a first class treatment: results of an eight-year experience with a comparison of patient and method survival in CAPD and hemodialysis.

An 8-year experience on CAPD, in a single center with all treatments of ESRF (end-stage renal failure) available, is presented. Method choice was left to the patient, after extensive counselling. However, CAPD selection was very negative, and CAPD patients were older, with a much larger percentage of diabetics and loaded by more risk factors, suggesting an influence of the staff preferences on patient choice. After a first period with unsatisfactory results, we obtained an important improvement of patient and method survival coinciding with the introduction of a new connector with disinfectant (Y-system) which allowed a reduction of peritonitis rate to 1 episode for 36 patient/months. For the period 1.1.81 to 31.12.86 a comparison was made (life table analysis) between new ESRF patients placed initially on CAPD or on HD. The 5-year survival was not statistically different in spite of the very negative CAPD selection of patients, who were 10 years older, on the average. Excluding diabetics, survival curves were identical in the two methods. Age at death and causes of death were not different. Method survival was better on HD (98% vs. 71% on CAPD, at 5 years, p less than 0.01): significance and limits of this evaluation are discussed. Drop-out figures were definitely lower than in the literature and this was attributed to the sharp reduction in peritonitis rate. Only 1.7% of CAPD patients discontinued the method due to inadequate ultrafiltration. In 29 CAPD and 28 HD patients with more than 4 years treatment some biochemical and clinical data were compared. Serum cholesterol was significantly higher and serum proteins lower in CAPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1987

Plasma concentrations of atrial natriuretic peptide in relation to body fluid status in chronic uraemia.

Basal plasma alpha-human natriuretic peptide (alpha-hANP) values were found to be significantly higher in 7 fluid-overloaded chronic dialysis patients than in 13 non-dialysed renal patients without extracellular fluid (ECF) expansion. Iso-osmotic reduction of the body weight by a single 3-h ultrafiltration caused alpha-hANP to decrease significantly in all anuric patients to values comparable to those of non-dialysed subjects. In this latter group, however, there was a significant inverse relationship between alpha-hANP and glomerular filtration rate but not between alpha-hANP and total blood volume. These findings suggest that both ECF expansion and impaired renal removal of alpha-hANP might be responsible for the high alpha-hANP in chronic uraemia.

Adult↗
PubMed1987

Ultrastructural renal findings in allografted kidneys of patients treated with ciclosporin A.

22 renal biopsies of 22 patients with 6-month-old transplants have been examined at the light- and electron-microscopic level to demonstrate the toxic effects induced by ciclosporin A (CS). These patients presented stable renal function and were exempt from acute rejection symptoms or nephrotoxicity. Interstitial fibrosis, tubular atrophy and interstitial lymphocytic infiltration were the lesions most often observed by light microscopy. In a single case an arteriolar lesion suggestive of arteriolopathy due to Cs was seen. Ultrastructural observations of renal tubular cells showed a tendency of rough and smooth endoplasmic reticulum to microdilate and microvacuolize. In 4 out of 22 cases there were mitochondrial alterations with giant mitochondria. In only 1 case, clusters of cilia were seen. Clinical histological correlations show that interstitial fibrosis is directly proportional to CS blood level. CS higher blood levels suggest a higher risk of nephrotoxicity.

Basement Membrane↗
PubMed1985

Herpes virus infection prevalence in regular haemodialysis patients--a comparative evaluation of complement fixation, indirect immunofluorescence and Elisa tests.

The presence and titres of specific serum IgG and IgM antibodies to cytomegalovirus, herpes simplex virus and varicella-zoster virus were evaluated in 50 haemodialysis patients by complement fixation, immunofluorescence and Elisa tests. A second serum sample was tested in 24 patients after four weeks. Specific serum IgG antibodies to Epstein-Barr virus were also measured by immunofluorescence in 26 patients. By immunofluorescence and Elisa tests, the prevalence of cytomegalovirus, herpes simplex virus and Epstein-Barr virus infection is approximately 100 per cent, and varicella-zoster virus 60 per cent. High titres of IgG specific antibodies found by Elisa tests, detection of IgM antibodies in 16-18 per cent of patients and sero-conversion in 25 per cent of patients, suggests continuous antigenic stimulation.

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

Problems of CAPD: progress of the 4 years' experience.

Results of four years' experience of CAPD in our Centre are reported. The incidence of peritonitis in 13 patients dropped with the use of Y-set from 1/4 patient-months to 1/26 p-m). As experience was gained we reduced the use of hypertonic bags and improved diet suggestions. By these interventions during the past year, we obtained a good control of triglycerides and cholesterol concentration and a reduction in weight gain.

Adolescent↗