[Kt calculation as a quality indicator of haemodialysis adequacy]. / Cálculo del Kt como indicador de calidad en el área de adecuación en hemodiálisis.

The haemodialysis dose is a good marker of dialysis adequacy, and we usually monitor it with Kt/V measure. The dialysis dose monitored with Kt allows a better discrimination, detecting a percentage of the patients that perhaps do not get an adequate dose for their gender or body surface area after treatment with a minimum recommended dose of Kt/V. The objective of this study was to evaluate Kt as a clinical indicator referred to dialysis adequacy in the haemodialysis population. The aim was that more than 85% of the patients would achieve the recommended Kt target for their gender (at least 50 litres in men and 45 litres in women), or their body surface area. In each of the patients (mean 129) the Kt mean value was determined for three consecutive dialysis sessions, one every two months, during the follow-up period (14 months). At the beginning, the Kt/V value was on target (> 1.3) in 93.2% of the patients, but only in 58% according to Kt measure for their gender. After 4 months, we observed that 85% of patients' Kt target increased for their gender, but only 68% did if we used the Kt individualised for their body surface area. From month 6 to the end of the follow-up period, more than 85% of patients obtained an adequate Kt for their body surface area (p < 0.001). A significant increase of Kt mean (5.4 litres) was observed at the end of the study (p < 0.001). The usual dialysis prescription parameters were modified increasing blood flow rate (34.14 ml/min, p < 0.001), session effective duration (8.04 minutes, p < 0.001), dialyser surface area (24.1% of patients changed from helixone 1.3 to 1.6 m2, p < 0.001) and haemodialysis modality (56.8% of patients changed from conventional haemodialysis to on-line haemodiafiltration, p < 0.001). We conclude that monitoring dialysis dose with Kt is a good clinical measure of adequacy, and using it as a quality indicator can be done in line with the more demanding quality standards.

Steroid metabolism in the cortex and the medulla of the early fetal bovine ovary.

Suspensions of cells obtained from the cortex and the medulla of the ovary of early bovine fetuses of 4-10 cm in crown-rump (C-R) length were used for studies of the metabolism of radiolabeled exogenous steroid precursors. Tritiated dehydroepiandrosterone, androstenedione, and testosterone were employed as precursors and their metabolic products were evaluated after separation by thin-layer chromatography. The extent of conversion of tritiated dehydroepiandrosterone to androstenedione was higher in cells from medulla than in those from the cortex. Androstenedione was metabolized mainly to estrone, and the percent of transformation was similar in the cortex and the medulla, but the rate of formation of 17 beta-estradiol was higher in the medulla than in the cortex. Furthermore, cells obtained from the cortex and the medulla aromatized testosterone to 17 beta-estradiol at a similar rate. In all cases, the percent of transformation was higher in ovaries from fetuses of 4.0 cm in C-R length than those from fetuses of 9.0-10.0 cm in C-R length. These data suggest that, in the bovine fetal ovary, the activity of 3 beta-hydroxysteroid dehydrogenase/isomerase and 17 beta-hydroxysteroid dehydrogenase predominates in the medulla, whereas aromatase activity is similar in the cortex and the medulla of the early fetal bovine ovary.

Androstenedione metabolism in the indifferent stage of bovine gonad development.

Suspensions of cells obtained from genital ridges and gonads of bovine embryos of 1.0-3.4 cm in crown-rump (C-R) length were used for studies of the metabolism of radiolabeled exogenous steroid precursor. Tritiated androstenedione was employed as precursor and the final products of their metabolism were evaluated after separation by thin-layer chromatography. Genetic sex was determined by the karyotype of hepatocytes from the same embryos. The extent of conversion of tritiated androstenedione was higher in cells from male embryos than cells from female embryos. Furthermore, androstenedione was metabolized mainly to testosterone in male embryos. By contrast, cells obtained from female embryos transformed androstenedione to estrone and 17 beta-estradiol. The onset of this activity was observed at 1.8 cm in C-R length in males and at 2.2 cm in C-R length in females. In all cases, after the onset, the metabolic activity increased in relation to the age of the embryos. These data show that in the bovine embryo gonad, the activity of aromatase and 17 beta-hydroxysteroid dehydrogenase are present when the morphological differentiation of the gonadal sex has not yet been established.

Newly hatched chick ovarian cell subpopulations metabolize distinctively progestin and androgen precursors.

The aim of this study was to characterize the ability of four different cell fractions (F1, F2, F3, and F4), isolated from the ovary of newly hatched chick by means of subsequent metrizamide gradients (0-15%), to metabolize progestins and androgens. The results showed the presence of 17 alpha-hydroxylase/C17-20 lyase and 3 beta-hydroxysteroid dehydrogenase/isomerase (3 beta-HSD) activities in the typical steroidogenic cells isolated in F1 (d = 1.012 g/ml). Primary oocytes present in F2 (d = 1.037 g/ml) did not show relevant steroid metabolism in the various assays that were carried out. Fractions 3 (d = 1.055 g/ml) and 4 (d = 1.071 g/ml), which contained a mixture of prefollicular and poorly differentiated epithelial cells, presented both 5 beta-reductase and aromatase activities, whereas 17 beta-HSD activity was mainly located in the cells of fraction 3. It is highly possible that poorly differentiated epithelial cells of fractions 3 and 4 are responsible for the steroidogenic activity. We conclude that in newly hatched chick ovary, typical steroidogenic cells metabolize progestins to androgens, and poorly differentiated epithelial cells further aromatize androgens to estrogens. In addition, we suggest the existence of at least two metabolically distinct poorly differentiated epithelial cell subpopulations, one presenting 5 beta-reductase and aromatase activities and another exhibiting 17 beta-HSD activity.

[Guide for the prevention of renal diseases during and after childhood]. / Guía para la prevención de las enfermedades renales en y desde la infancia.

Kidney disease Prevention in childhood can be made from three levels. In the first level or Primary Prevention one must prevent kidney disease taking steps for "Kidney Health" promotion: environmental factors, nourishing, sanitary education and preventive pediatrics. Secondary Prevention lies in the correct diagnostic during first years in life and in a suitable treatment of the kidney diseases, especially in children to have a kidney failure risk: obstructive uropathy and vesicoureteral reflux. Tertiary Prevention deals with aggravating factors in an established Kidney chronic failure, and its prevention includes: normoproteic diet, phosphorus restriction, arterial hypertension control and nutritional and pharmacological steps to reduce the hyperlipidemia.

[Infrequent manifestations of Henoch-Schonlein purpura]. / Manifestaciones infrecuentes en la púrpura de Schönlein-Henoch.

We review the cases of 148 children with Henoch-Schönlein purpura diagnosed in a period of seventeen years (from 1975 to 1992). Thirteen cases (8.7%) of unusual clinical manifestations were found: testicular affection in six cases (7.6% of the males); IgA nephropathy in four (2.7%); exudative enteropathy in two (1.3%); duodenal syndrome in two; previous abdominal manifestation which led to surgical procedures in one (0.7%) and another case with detachment of the retina. These clinical findings are analyzed and the possibility of unnecessary therapeutic acts is discussed.