Sirolimus is primarily used as a rescue agent in pediatric transplant recipients, particularly in cases of cyclosporine or tacrolimus toxicity. Preliminary data indicate a higher apparent oral clearance in younger children (4-10 years of age). Various drug interactions have been described between sirolimus and drugs that are substrates/inhibitors or inducers of CYP3A and the P-glycoprotein transporter. Close monitoring of trough sirolimus blood levels is therefore recommended for pediatric transplant recipients. In de novo adult kidney transplant recipients on triple therapy with cyclosporine, corticosteroids and sirolimus, a therapeutic window of 4-12 mug/l is recommended for sirolimus trough concentrations determined by HPLC or LC/MS-MS. In maintenance adult patients after conversion to a calcineurin inhibitor-free regimen, sirofirmis trough concentrations of 5-10 mug/l are proposed in combination with mycophenolate mofetil. These therapeutic ranges may also serve as a guide for pediatric renal transplant recipients.The concept Of C-2 monitoring still needs to be critically evaluated in pediatric patients. The crucial importance of achieving an adequate cyclosporine exposure early after transplantation has been demonstrated for adult transplant recipients. A cyclosporine concentration taken 2 h after dosing is a good surrogate marker of the AUC(0-4h) in adults. Various clinical studies have shown that in pediatric patients, the C-2 concentration shows a substantially better correlation with cyclosporine exposure compared to the trough level (CO). In an outcome study with pediatric renal transplant recipients, it could be demonstrated that the AUC(0-4h) was a predictor of acute rejection in the first 3 weeks after transplantation, whereas C-2 levels showed no significant association. Abbreviated AUC strategies may be preferable for optimization of CsA exposure in pediatric patients. (C) 2004 The Canadian Society of Clinical Chemists. All rights reserved.

PURPOSE To assess combined static-dynamic magnetic resonance (MR) urography in the evaluation of congenital urinary tract dilatation in infants and children. MATERIALS AND METHODS Sixty-two patients with urinary tract dilatation underwent prospective examination with combined static-dynamic MR urography. A combination examination involved use of a static T2-weighted three-dimensional inversion-recovery fast spin-echo sequence and a dynamic T1-weighted two-dimensional fast field-echo sequence with gadopentetate dimeglumine-DTPA and furosemide application. Twelve additional patients underwent examination with only static MR urography. Thus, both image quality and morphologic features were assessed in 74 patients with the use of MR urography. The results were compared with those of ultrasonography and, when available, conventional urography or surgery. In 62 patients, the dynamic sequence was used to calculate split renal function from renograms generated from parenchymal regions of interest and to assess urinary excretion from whole-kidney renograms. Results were compared with those of diuretic renal scintigraphy (DRS) for split function (Spearman rank correlation coefficient) and urinary excretion (kappa coefficient). RESULTS Stenoses at the ureteropelvic (n = 33) and ureterovesical (n = 31) junctions and within the ureter (n = 3) and nonstenotic dilatation (n = 23) were clearly depicted, while the normal urinary tract (n = 51) was depicted in its entirety in 47 of 51 examinations. Image quality was considered good or excellent in 95% of the kidney-ureter units. For split renal function, dynamic MR urography and DRS showed significant correlation (r = 0.92, P <.001). For urinary excretion, MR urography and DRS showed strong agreement (kappa = 0.67), with concordant classification of urinary excretion in 59 (81%) of 73 abnormal kidney-ureter units and in all 47 (100%) normal kidney-ureter units. CONCLUSION Combined static-dynamic MR urography provides high-quality depiction of the urinary tract in infants and children, while allowing accurate determination of single-kidney function and reliable evaluation of urinary excretion.

Bei 46 Kindern mit Harnwegsdilatation (14 Doppelnieren) wurden sta­tisch-dynamische MRU und Nierenszintigraphie durchgeführt. Die MRU besteht aus einer statischen Sequenz zur dreidimensionalen Darstellung der harnableitenden Wege und aus ei­ner dynamischen Sequenz nach i.v.-Injektion von Gd-DTPA zur Bestimmung von seitenge­trennter Nierenfunktion und Harnabfluß. Die MRU bildete das gesamte harnableitende Sy­stem exzellent ab mit eindeutiger Stenoselokalisation. Die mit MRU errechnete Nierenfunk­tion korrelierte hochsignifikant zum jeweiligen szintigraphisch ermittelten Ergebnis. Bei den Doppelnieren war die MRU in der Ermittlung der Partialorganfunktion der Szintigraphie überlegen. Harnabflußstörungen wurden tendentiell überschätzt. Besondere Vorteile der Me­thode liegen in der exakten Korrelation von Funktion und Morphologie.

Computer-assisted instruction (CAI) programs based on internet technologies, especially on the world wide web (WWW), provide new opportunities in medical education. The aim of this paper is to examine different aspects of such programs, which we call 'web-based training (WBT) programs', and to differentiate them from conventional CAI programs. First, we will distinguish five different interaction types: presentation; browsing; tutorial dialogue; drill and practice; and simulation. In contrast to conventional CAI, there are four architectural types of WBT programs: client-based; remote data and knowledge; distributed teaching; and server-based. We will discuss the implications of the different architectures for developing WBT software. WBT programs have to meet other requirements than conventional CAI programs. The most important tools and programming languages for developing WBT programs will be listed and assigned to the architecture types. For the future, we expect a trend from conventional CAI towards WBT programs.