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Biomedical subjects

V Barrio

Publications and source records attributed to V Barrio.

14 recordsLinked to original sources
PubMed1995

Severe renal hypouricemia secondary to hyperbilirubinemia.

A 64-year-old man with alcoholic liver cirrhosis had a progressive decrease in the serum uric acid (UA) until it became undetectable, an increase renal UA clearance, mild glycosuria with normal serum glucose and a decrease in the tubular reabsorption of phosphate in association with cholestasis secondary to a gallbladder carcinoma. All these abnormalities returned to normal when the serum bilirubin levels decreased following surgical treatment. This clinical observation suggests that the reversible renal tubular transport defect was secondary to high levels of serum bilirubin.

Bilirubin↗
PubMed1990

Effect of calcitriol on insulin secretion in uraemia.

To evaluate the role of calcitriol on insulin secretion in uraemia, nine patients on maintenance haemodialysis, never treated with vitamin D nor with calcium-channel blockers, were studied. Baseline glucose, insulin, C peptide, calcium, intact PTH, and calcitriol serum values were measured, and after an oral load of 75 g glucose, insulin and C peptide were also determined at 15, 30, 45, 60, and 120 min. Following 14 days of treatment with oral calcitriol (0.5 microgram/day), the same study protocol was applied. Serum calcitriol values, which were low as expected, increased after therapy, but did not reach the values observed in healthy controls. Despite no change in total serum calcium, intact PTH values decreased significantly (182 vs 88.3 ng/ml, P less than 0.003). Baseline serum insulin was significantly increased after calcitriol (7.5 vs 35 microU/ml, P less than 0.001). Similarly, an enhancement in insulin secretion following calcitriol was observed at 15 min (34 vs 70, P less than 0.01) and 30 min (57 vs 96 microU/ml, P less than 0.01). Computation of the total area under the curve confirmed these results. Changes in C peptide profile paralleled those described for insulin. These data confirm that vitamin D modulates pancreatic beta-cell secretion and suggest that calcitriol may regulate insulin release in uraemic patients.

Adult↗
PubMed1989

Beta-2-microglobulin in the assessment of renal function in full term newborns following perinatal asphyxia.

In order to evaluate the clinical usefulness of serum and urinary beta 2 microglobulin (beta 2-m) determination as a marker of renal damage following perinatal asphyxia, twenty asphyxiated and twenty healthy full term newborns were studied. Renal function was monitored on the first and third day after birth by traditional tests such as creatinine (Cr), endogenous creatinine clearance (Ccr), and fractional Na excretion (FeNa), as well as by serum and urinary beta 2 microglobulin. The value of different tests for the diagnosis of oliguria and of acute renal failure was determined. Eleven asphyxiated neonates developed oliguria and five ARF in contrast to none of the controls. Both traditional tests of renal function, and determinations of beta 2-m with the exception of serum beta 2-m, were significantly different (p less than 0.01) between controls and asphyxiated neonates. When stratified analysis was performed, only serum cr, urinary beta 2-m/cr ratio, and Fe beta 2-m were able to discriminate oliguria from preserved diuresis on the first day of life. For ARF, only Ccr and Fe beta 2-m were different, again on the first day of life. Urinary beta 2-m/creatinine ratio and Fe beta 2-m appear to be more sensitive and specific for the early detection of proximal tubular renal dysfunction following perinatal asphyxia than usual tests of renal function.

Asphyxia Neonatorum↗
PubMed1989

Factors affecting beta 2-microglobulin plasma concentration during hemodialysis.

We studied ten patients on hemodialysis (HD) treated in sequence with cuprophan (CU), ethylenevinylalcohol (EVAL), polyacrylonitrile (A-69) and polysulphone (PSP) membrane dialyzers. beta 2-microglobulin (beta 2m) was measured by radioimmunoassay in plasma and dialysate samples. Plasma concentrations were corrected for changes in extracellular volume (ECV). We also studied adsorption in vitro by incubating the above membranes with I-125-labelled beta 2m. There were no changes in beta 2m plasma concentration after HD with CU dialyzers, but a significant decrease was observed with the other membranes tested. Filtration of beta 2m across the dialyzer was absent with CU and minimal with EVAL. However, large amounts were recovered from dialysate with the high-permeability dialyzers, AN-69 and PSP. In vitro studies showed that maximal adsorption capacity was obtained with AN-69 (13%) compared to 9% with CU, 4% with EVAL and 7% with PSP. In summary, beta 2m clearance with PSP is achieved through greater removal of this protein by mass transport across the membrane. The mechanism by which beta 2m is removed from blood during AN-69 dialysis seems to include both adsorption to and filtration by the membrane itself.

Adolescent↗
PubMed1988

Atrial natriuretic peptide inhibits angiotensin II-induced contraction of isolated glomeruli and cultured glomerular mesangial cells of rats: the role of calcium.

We examined the contractile effect of angiotensin II on isolated rat glomeruli and cultured glomerular mesangial cells, as well as the possible involvement of calcium in this contraction. In addition, the effect of rat atrial natriuretic peptide (ANP) on angiotensin II-induced contraction was studied. Computer-assisted image analysis was used to measure glomerular cross-sectional area and planar mesangial cell surface area in several experimental conditions. Angiotensin II induced a decrease in glomerular cross-sectional area and planar mesangial cell surface area that was both time and dose dependent. This effect was partially blocked by preincubation with verapamil or TMB-8, the latter compound being more effective. Incubation with ANP prevented angiotensin II-induced reduction of glomerular cross-sectional area and planar mesangial cell surface area and reversed contraction in mesangial cells. Incubation with TMB-8 impaired the effect of ANP. These data suggest that angiotensin II could exert part of its physiologic effects in the kidney through calcium-dependent mesangial and glomerular contraction. ANP inhibited this contraction, possibly explaining some of its renal effects.

Angiotensin II↗
PubMed1987

Atrial natriuretic peptide inhibits glomerular contraction induced by angiotensin II and platelet activating factor.

Isolated rat glomeruli were incubated with angiotensin II, PAF and atrial natriuretic peptide (ANP). Angiotensin II and PAF produced a significant glomerular contraction as evidenced by the decrease in glomerular cross-sectional area. The addition of ANP abolished this effect. These results suggest that ANP could modulate glomerular filtration rate, not only by inducing changes in intrarenal hemodynamics, but also by preventing the effect of some hormones on the filtration surface and subsequently on the ultrafiltration coefficient.

Angiotensin II↗
PubMed1987

Adenosine induces a calcium-dependent glomerular contraction.

Glomeruli isolated from rat kidney cortex were incubated with adenosine in the presence or absence of verapamil and calcium and their change in cross-sectional area was recorded. Adenosine induced a 10% decrease in glomerular cross-sectional area. This decrease was blocked by verapamil or a calcium-free medium. The results suggest that the effect of adenosine in the kidney could be due to glomerular constriction, and that this constriction depends on the entry of calcium into glomerular cells.

Adenosine↗
PubMed1987

Changes in glomerular cross-sectional area induced by platelet activating factor.

Isolated glomeruli from normal rats were incubated with platelet-activating factor 10(-6) M at variable incubation times (8, 15, 30 and 45 min) and with different concentrations (0 to 10(-6) M) for 20 min. In addition, the platelet-activating factor effect (10(-6) or 10(-8) M, 20 min) was tested in the presence of BN-52021 (10 or 50 micrograms/ml), verapamil (10(-5) M), acetylsalicylate of lysine (10(-3) M), and in a free-calcium media with EGTA 2 mM. Glomerular microphotographs were taken before and 20 min after adding the substances, and glomerular cross-sectional area was measured using a computerised technique. Platelet-activating factor induced a significant time-dependent reduction in glomerular cross-sectional area, from a concentration of 10(-8) M. BN-52021, verapamil, and the free-calcium media inhibited platelet-activating factor-induced reduction of glomerular cross-sectional area, but acetylsalicylate of lysine did not. Platelet-activating factor-induced reduction in glomerular cross-sectional area seems to be dependent on the interaction of platelet-activating factor with a specific glomerular receptor, with a subsequent modification of the intracellular concentration of calcium. Arachidonic acid metabolites from the cyclo-oxygenase pathway do not seem to be involved in these phenomena. Results suggest that platelet-activating factor could modulate glomerular filtration rate not only by inducing changes in systemic or intrarenal haemodynamics, but also by modifying the filtration surface, thus reducing the Kf.

Animals↗
PubMedDate not supplied

Beta-2-microglobulin as an index of renal function after cardiopulmonary bypass surgery in children.

In order to evaluate the clinical usefulness of serum and urinary beta-2-microglobulin (beta 2-m) determination as a marker of renal damage following cardiopulmonary bypass surgery (CPB), 37 children, with an age range of 6 months to 13 years undergoing CPB under hypothermia and cardioplegia for congenital malformations, were studied. Renal function was monitored at baseline and on the first and third day after CPB by traditional tests such as creatinine (Cr), endogenous creatinine clearance (Ccr), and fractional sodium excretion (FeNa), as well as by serum and urinary beta 2-m measured by radioimmunosorbent assay. Data were analyzed for the group as a whole and after stratification for the presence of acute renal failure (ARF) defined by an increase in Cr greater than 0.5 mg/dl and/or FeNa greater than 2% and of renal hypoperfusion which was considered in case of hypotension resistant to volume repletion and/or dopamine infusion and of oliguria (less than 1.0 ml/kg/h). The incidence of ARF was 18.9%, mortality 21.7% and among those who developed ARF, 71.4%. Although Cr and FeNa increased significantly on the first postoperative day, values returned to baseline thereafter, probably because of the high mortality rate observed among those who developed ARF and were therefore lost to follow-up. In contrast, Ccr was significantly decreased during the whole study. Even though serum beta 2-m displayed a similar profile to Cr and FeNa returning to baseline by the third day, urinary and fractional excretion of beta 2-m were significantly increased at any time of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗