Biomedical subjects

E Balzar

Publications and source records attributed to E Balzar.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Ciclosporin monitoring in kidney-transplanted children: high-performance liquid chromatography versus radioimmunoassay.

Due to large individual differences in absorption, utilization and metabolism of the predominantly used drug ciclosporin (CsA) for selective immunosuppression in kidney graft recipients, therapeutic blood levels (immunosuppression/toxicity) can be maintained only by frequent measurements of the CsA concentrations in blood samples and dosage readjustments. The purpose of the present study was to investigate the usefulness of a high-performance liquid chromatography (HPLC) method for native CsA and a radioimmunoassay (RIA) method for CsA and metabolites measuring simultaneously using both HPLC and RIA and creatinine serum levels (Crea) in whole blood samples from 19 kidney-transplanted children over a 3-year observation period. By comparison of the results of HPLC, RIA and Crea determinations (n = 1,284) we found a highly variable metabolization rate (RIA/HPLC ratio) of 5.25 +/- 2.33 (range 1.37-12.9). No direct correlation was found between changes in RIA/HPLC ratios and kidney function, rejection and infection periods. Dosage/HPLC and dosage/RIA showed no significant correlation. A higher correlation between HPLC, Crea and nephrotoxicity was found than between RIA and Crea. Because of rapid and large variations of CsA metabolization rates in young allograft recipients, we recommend measurements of CsA blood concentrations with any HPLC method specific for unchanged drug, since CsA metabolites detected by RIA, at least those which are most abundant, have less immunosuppressive and toxic effects.

Adolescent↗

PubMedDate not supplied

Neopterin and interferon gamma serum levels in renal allograft recipients.

In the follow-up of children receiving renal allografts the early differential diagnosis of infections and rejection episodes is the main problem. Serum levels of neopterin (N), a pteridine released from stimulated macrophages, was determined by radioimmunoassay. Also interferon-gamma (IF) serum levels, a marker of T lymphocyte activity, were determined with an immunoradiometric assay in 19 kidney-transplanted children. Both, infections and rejection episodes, are accompanied by distinct increases in N. The IF are elevated 1-3 days earlier than N, the median values during infections being significantly (p less than or equal to 0.001) higher than those during rejection crises. The routine measurement of N and IF allow the simple, quick and reliable monitoring of the immune status, which seems to be of a high relevance for the daily monitoring of transplant recipients.

Adolescent↗

PubMedDate not supplied

Estimation of total creatinine clearance is unreliable in children on peritoneal dialysis.

OBJECTIVE: To test the reliability of creatinine clearance in children on peritoneal dialysis (PD). DESIGN: Longitudinal, case-controlled. SETTING: Routine clinic visits at the pediatric dialysis unit of the Universitätskinderklinik of Vienna. PATIENTS: Eleven children (2-13 years, 10-55 kg) with end-stage renal disease on PD. INTERVENTIONS: Creatinine clearance (CCr) was determined by measuring creatinine excretion (ECr) over 24 hours in both dialysate and urine. Each child had three to five separate measurements of their CCr. At the same time we also calculated the Schwartz formula clearance from the patient's height and serum creatinine, using a modified correlate. MAIN OUTCOME MEASURES: Reliability of CCr was assessed by two approaches. First, we compared each serial measurement with the mean value for each patient and thereby assessed the "intramethodical" variability. Second, we compared each CCr with the simultaneous formula clearance and assessed the "intermethodical" disagreement. RESULTS: Twenty-seven percent of the measurements of CCr were classified as unreliable based on a comparison with the mean value for each patient. Reliability was closely correlated with residual renal function (p < 0.01); only 12% of the measurements in the anuric patients were classified as unreliable (vs 31% in the patients with residual renal function). The simultaneous formula clearance was less variable than the CCr. The formula clearance had a sensitivity of 93% and a specificity of 60% for detecting unreliable values of CCr. CONCLUSION: Estimation of total CCr is unreliable in pediatric patients on PD. A simultaneous formula clearance can be used to detect which values are unreliable.

Case-Control Studies↗