Angiotensin-converting enzyme inhibition attenuates renal platelet-derived growth factor gene expression and cell proliferation in subtotal nephrectomy

Cell proliferation, matrix accumulation and cell infiltration are characteristic features of progressive glomerulosclerosis and tubulointerstitial fibrosis. Platelet‐derived growth factor (PDGF), a cytokine which has proliferative, prosclerotic and chemokine properties, has been shown to be upregulated in the rat remnant kidney model. Inhibition of the renin–angiotensin system by angiotensin‐converting enzyme (ACE) inhibitors has a beneficial effect on renal function and morphology, but the effect of ACE inhibition on PDGF gene expression and PDGF‐mediated cellular proliferation in subtotal nephrectomy has not been studied in detail. Twelve rats were subtotally nephrectomized (STNx) and received either the ACE inhibitor perindopril or a placebo for 12 weeks. Five sham‐operated rats served as controls. Subtotal nephrectomy was associated with hypertension, proteinuria, elevated plasma creatinine and increased kidney weight. After 12 weeks, PDGF B‐chain mRNA was significantly upregulated in the glomeruli and tubulointerstitium of subtotally nephrectomized rats. ACE inhibition attenuated PDGF mRNA expression in association with a reduction in tubular and glomerular proliferation, as assessed by staining for proliferating cell nuclear antigen. In the context of the known in vitro and in vivo effects of PDGF, it is postulated that the renoprotective action of ACE inhibitors may be partially related to PDGF‐mediated antiproliferative mechanisms.     

Scoring and performance of analysis and interpretation of toxicologic cases assessed by external quality assurance.

Quantitative analysis of toxicology cases requires knowledgeable interpretation. We describe a scoring scheme that integrates analytical and interpretive performance for such cases using a reward/penalty scoring scheme. This scheme has been validated on cases circulated over the previous 5 years to volunteer participants in the UKNEQAS for Drug Assays Scheme. We have been able to identify a subset of poorly performing laboratories that should desist from toxicologic analysis and interpretation.     

Predictors of Compliance in Toddlers: Child Temperament, Maternal Personality, and Emotional Availability. Portions of the research were presented at the Conference on Human Development, Mobile, AL, March 6, 1998.

Fifty-one mother-toddler (15 to 31 months) dyads participated in a study on the predictors of compliance. Mothers completed two questionnaires: the Multidimensional Personality Questionnaire (Tellegen, 1982), a measure of maternal personality, and the Toddler Behavior Assessment Questionnaire (Goldsmith, 1987), a measure of child temperament. A free play period in the laboratory provided the observations for scoring the quality of the mother-toddler interactions with the Emotional Availability Scales (Biringen, Robinson, and Emde, 1993). The following clean-up task in which children were asked to help put the toys in the basket provided the observations for scoring compliance with maternal directives. Emotional availability was the strongest predictor of compliance, especially the maternal variables of sensitivity and structuring. Child temperament was also implicated, with high compliance toddlers perceived by their mothers to be less socially fearful and less prone to anger than their less compliant peers. The results are discussed in terms of the contribution of the mother-child emotional climate to the development of compliance.