Dialytic clearance of urea is efficient, but other small solutes normally secreted by the kidney may be cleared less efficiently. This study tested whether the high concentrations of these solutes in hemodialysis patients reflect a failure of passive diffusion methods to duplicate the efficacy of clearance by tubular secretion. We compared the plasma concentrations and clearance rates of four solutes normally cleared by tubular secretion with the plasma concentrations and clearance rates of urea and creatinine in patients receiving maintenance hemodialysis and normal subjects. The predialysis concentrations (relative to normal subjects) of unbound phenylacetylglutamine (122-fold), hippurate (108-fold), indoxyl sulfate (116-fold), and p-cresol sulfate (41-fold) were much greater than the concentrations of urea (5-fold) and creatinine (13-fold). The dialytic clearance rates (relative to normal subjects) of unbound phenylacetylglutamine (0.37-fold), hippurate (0.16-fold), indoxyl sulfate (0.21-fold), and p-cresol sulfate (0.39-fold) were much lower than the rates of urea (4.2-fold) and creatinine (1.3-fold). Mathematical modeling showed that prominent accumulation of the normally secreted solutes in hemodialysis patients could be accounted for by lower dialytic clearance relative to physiologic clearance combined with the intermittency of treatment. Whether or not more efficient removal of normally secreted solutes improves outcomes in dialysis patients remains to be tested.

The internal consistency, one-year stability, and cross-sectional and longitudinal correlates of a global life satisfaction measure, the Students' Life Satisfaction Scale (SLSS: Huebner, 1991a), were investigated. The SLSS and Behavior Assessment System for Children-Self-Report-Adolescent Form (BASC: Reynolds & Kamphaus, 1992) were both administered to a sample of high school students on two occasions separated by one year. Alpha coefficients indicated adequate internal consistency for research purposes. The one-year test-retest coefficient suggested moderate stability of adolescent reports. Cross-sectional and longitudinal patterns of correlations between the SLSS and BASC Adaptive and Clinical measures were consistent with expectations for the most part and suggested that SLSS scores have meaningful relations with important mental health variables. It was concluded that greater attention should be devoted to the study of life satisfaction in children and youth.

life satisfaction, measurement, adolescence,