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Biomedical subjects

F de Alvaro

Publications and source records attributed to F de Alvaro.

27 records · Page 2Linked to original sources
PubMed1993

An analysis of adequacy of dialysis in a selected population on CAPD for over 3 years: the influence of urea and creatinine kinetics.

Adequacy of dialysis is addressed to minimize the negative consequences of underdialysis. The results of the NCSD demonstrated that urea kinetic modelling (UKM) is a useful tool in the measurement of adequacy of dialysis: Kt/V values of 1 are considered adequate to prevent complications when daily protein intake is appropriate. For CAPD no similar prospective studies exist, and consequently there is no information comparable to that for haemodialysis. Preliminary data have communicated controversial results about the usefulness of UKM for CAPD prescription. On the other hand creatinine kinetics has been proposed as an alternative to UKM to define adequacy of dialysis on CAPD. However, these results should be considered preliminary because of the small size of the series and the short observation period. The objective of this paper is to study the role of these two kinetic models in defining adequacy of dialysis in a long-term, selected CAPD population. We have studied 56 patients treated for at least 3 years on CAPD (3-11 years; mean observation period 5 years; 3996 patient-months). Urea kinetic model (UKM) (urea weekly (W) Kt/V and NPCR) and creatinine kinetics (Efficacy number (EN) and K) were determined annually. According to the present data we can conclude that Kt/V is an appropriate tool for defining adequacy in patients on CAPD. Values of weekly Kt/V greater than 1.7-1.8, with NPCR more than 1 g/kg/day, assure an adequate clinical outcome. Conversely, values on the Kt/V scale less than 1.7 entail a greater rate of complications. Our data also confirm that maintaining a serum albumin > 536-551 mumol/l (3.7-3.8 g/dl) is related to lower morbidity and mortality, and should be a major objective for CAPD patients. Consequently a relationship between dose of dialysis in terms of urea mass balance and protein nutrition can be established. After 5 years on CAPD, when all residual renal function is generally lost, Kt/V values in excess of 1.9 are difficult to achieve. Based on currently available information, we do agree with the interest of performing a prospective study on adequacy of dialysis based on the urea kinetic model in CAPD, which definitely defines its role. On the other hand, creatinine kinetics did not show sufficient discriminative capacity in terms of adequacy of dialysis. EN and Kt of creatinine values in the lower range (4.5-6 and less than 45-50 1/week respectively) were not necessarily associated with a poorer clinical outcome.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Effects of alloxan-induced diabetes on hemorheology in rabbits.

Plasma viscosity (PV), apparent whole blood viscosity (WBV), relative blood viscosity (RV) and erythrocyte deformability (filterability) (EDF) were determined in 13 New Zealand White (NZW) rabbits with alloxan induced-diabetes (AID) and 8 normal NZW rabbits, matched for age, sex and weight. AID rabbits were divided into two groups depending on the duration of hyperglycemia (long-term, greater than 6.0 months (n = 7), and short-term, less than or equal to 3.0 months of hyperglycemia, n = 6). Comparing long-term AID rabbits to normal animals, we found significant increases in WBV (P less than 0.001, 0.005 for high and low rates of shear, respectively), and a marked reduction in EDF (P less than 0.001). There was no significant difference in PV between long-term AID and normal rabbits. Conversely, PV was significantly increased in rabbits with short-term diabetes (P less than 0.01) while there was a concurrent significant increase in WBV measured at high and low rates of shear (P less than 0.001, 0.001, respectively). No difference was detected in EDF between normal and short-term AID rabbits. Furthermore, in long-term AID rabbits there was a strongly positive correlation between RV and reduced erythrocyte deformability (r = 0.94, P = 0.006) while WBV strongly correlated with PV (r = 0.92, P = 0.004) in the short-term AID subgroup. We conclude from these data: (1) elevated blood viscosity in long term AID rabbits is associated with reduced erythrocyte filterability; and (2) elevated WBV in short-term AID rabbits is associated with increased PV.

Animals↗
PubMed1992

Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-I (PAI-I) levels in plasma and peritoneal effluent in patients on CAPD.

The formation of fibrin on peritoneal surface has been related to the appearance of adhesions both, in surgical and CAPD patients. It is known that mesothelial cells have fibrinolytic activity related with t-PA production. We studied plasma and overnight peritoneal effluent (OPE) from 20 CAPD stable patients. Antigenic PAI and t-PA were determined. These values and its correspondent peritoneal saturation indexes were compared to urea and creatinine MTCs, peritonitis incidence, UF capacity, protein losses, Pi, Ca, Na, CO2t, urea and creatinine OPE levels. Plasma t-PA 6.64 +/- 4.68 (2.4-20); Plasma PAI-I 24.8 +/- 17.1 (p < 0.001 in respect to controls) (4-62); OPEt-PA 1.46 +/- 0.95 (0.4-4.6); OPE PAI-I 7.3 +/- 5.6 (0-20.4). Peritoneal saturation ratios were for t-PA 29.6 +/- 21% (6-65) and for PAI-I 34 +/- 32% (7-132). In conclusion our data do not support strong relationship between peritoneal t-PA/PAI system and the functional characteristics of the peritoneal membrane although plasma PAI-I, after an increase in patients at early stages on CAPD, shows a tendency to decrease over time and frequent peritonitis. The values of peritoneal saturation ratios for t-PA/PAI are higher than expected for their molecular weight, which suggests local production. An elevated plasma t-PA levels has been found in older patients.

Adult↗
PubMed1992

Staphylococcus aureus nasal carrier status (SANCS) in CAPD patients; is it induced or favored by subcutaneous rHu-erythropoietin?

Staphylococcus aureus nasal carriage status (SANCS) has been recognized as a risk factor for patients on CAPD, due to a higher probability of suffering peritoneal catheter infections. The use of subcutaneous drugs (insulin dependent diabetics, drug addicts, HD patients and antiallergic vaccines), has been associated with increased risk of SANCS. On CAPD, erythropoietin (EPO) is almost universally used by the subcutaneous route. The objective of this paper was to evaluate the incidence and prevalence of SANCS in 85 CAPD patients by means of nasal smear and the influence of SANCS on peritoneal and catheter infection rate. Patients were divided in four groups according to diabetic status and EPO treatment (mean dose 2000 u. twice a week). The prevalence of SANCS in control groups was 30% in non-diabetics and 23% in diabetics. EPO treated patients showed a prevalence of SANCS of 39% in non-diabetics and 45% in diabetics due to the presence of 7 and 5 carrier patients respectively. SANCS patients (29% of the population), suffered 45% of peritonitis and 42% of exit-site infections caused by S. aureus. In a prospective part of the study, there was no difference in the frequency of developing positive cultures among EPO and control (30% of patients). No male EPO treated patients developed SANCS. We conclude that it is necessary to monitor S. aureus nasal carrier status periodically in CAPD patients especially in women. Whether or not subcutaneous erythropoietin treatment is implicated pathogenetically with SANCS, is not clarified by our data because of the frequent spontaneous appearance of SANCS among CAPD patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-Sectional Studies↗
PubMed1989

Comparative study of two different routes for insulin administration in CAPD diabetic patients. A multicenter study.

CAPD has been considered an appropriate method for treatment of diabetics in renal failure. Up to now the choice of route for insulin administration in these patients has not been definitely defined, although there is a general consensus for employing the intraperitoneal route for this purpose. However, contradictory data have appeared on this subject. Our aim has been to investigate whether the subcutaneous or intraperitoneal route makes any difference to metabolic control, and if so what is the price in terms of the incidence of peritonitis. Two groups of diabetic patients from three different hospitals with a similar peritonitis incidence and training protocols were studied. Of the 30 patients, 15 were treated with subcutaneous insulin (sc group) and in the other 15 the intraperitoneal route was employed (ip. group). The average follow-up period was 20.8 +/- 7.5 months for sc group and 18.7 +/- 8 months for ip. group. Insulin requirements were 30 +/- 11 u./day in the sc. and 110 +/- 60 u/day in the i.p. group (p less than 0.05) and remained constant during the study period. Metabolic controls (home glucose levels, HbA1C, hospital fasting glucose levels) were similar for both groups. However, the incidence of peritonitis was 4 times greater in the ip. group. In the ip. group 18 peritonitis episodes were registered in 280 patient-months vs 5 episodes in sc. group in 312 patient-months. We conclude that the intraperitoneal route for insulin administration in diabetic CAPD patients produces a higher risk of suffering peritonitis with no real metabolic improvement in the medium term.

Blood Glucose↗
PubMedDate not supplied

[Idiopathic membranous nephropathy in an elderly patient with type 2 diabetes mellitus].

We report an 85 years-old patient with type 2 diabetes mellitus and both clinical and biochemical nephrotic syndrome. The renal biopsy showed membranous nephropathy at stage I-II. There was no evidence of malignancy. The patient was treated with steroids, and two months later the proteinuria had not improved. The objects under discussion are the factors that should lead to suspect the existence of glomerulonephritis, other than diabetic glomerulosclerosis, suggesting the need for kidney biopsy. We also focus on the prognostic and therapeutic relevance, as well as on the common pathogenic aspects.

Adrenal Cortex Hormones↗
PubMedDate not supplied

[Experimental renal insufficiency in rabbits produced by the intrarenal injection of cyanoacrylic ester].

Through a percutaneous intrarenal injection of 2 ml cyanoacrylic ester to each kidney, acute renal failure was induced in 10 experimental rabbits. Seven of the animals died as a consequence of uremia before a period of 64 hours. The other three remained alive for 96 hours although suffering from stable renal failure. Cyanoacrylic ester solidifies immediately after injection, leading to a hardened body which fills the renal pelvis, ureters and also the renal vessels. Each injection induces hydronephrosis and necrotic-hemorrhagic lesions, and infarcts in the case of vascular injection. With this simple technique immediate acute renal failure can be obtained experimentally without causing trauma or involving extrarenal structures.

Acrylates↗