The relationships between drug dosage per injection and response rate, and drug dosage per injection and total daily drug intake were ascertained in Rhesus monkeys which self-administered cocaine, pipradrol, methylphenidate and phenmetrazine intravenously. The study demonstrated the monkeys would selfadminister all of these compounds over a wide range of dosages. Furthermore, the magnitude of reinforcement, i.e., dosage per injection, and the rate of responding in self-administering these compounds were inversely related. However, total daily drug intake was independent of the dosage per injection over a wide range of dosages. The results indicate that either the subjects can compensate for large changes in unit dosage so that daily drug intake remains stable or that a direct effect of these compounds functions in limiting their self-administration.

A progressive decrease was observed in the 5-methyldeoxycytidine content of hepatic DNA in male F344 rats fed with a hepatocarcinogenic methyl-deficient diet. The same dietary regimen resulted in altered hepatic contents of S-adenosylmethionine, the methyl-donating species, and S-adenosylhomocysteine, an inhibitor of DNA methylase. The data indicate that this carcinogenic dietary manipulation is sufficient to alter a possible regulatory process, DNA methylation.

The effects of acute and chronic chlorpromazine treatment on psychomotor stimulant self-administration behavior in the Rhesus monkey were determined. Chlorpromazine treatment significantly increased the frequency of self-administration of cocaine, pipradrol, phenmetrazine, d-amphetamine and methyIphenidate. The basis of this effect was thought to either be due to an antagonism of the reinforcing effect of these compounds or an antagonism of those actions of the psychomotor stimulants which may function in limiting their selfadministration.

Objectives. To determine the value of employing the Learning and Study Strategies Inventory (LASSI), Defining Issues Test (DIT), and Watson-Glaser Critical Thinking Appraisal (WGCTA) in predictive models for first-year pharmacy student academic performance. Methods. Six years of pharmacy student admission and progression data were evaluated. Additional predictive validity offered by these variables over a model of prepharmacy grade point average and pharmacy college admission test (PCAT) score was examined. Results. None of the 3 measures offered the ability to predict first-semester or first-year academic performance over and above GPA and PCAT. Conclusions. The LASSI, DIT, and WGCTA do not appear to assess abilities that are directly related to academic performance; however, these instruments may be useful in assessing other student attributes that are highly desirable for the practice of pharmacy.

This population-based case-control study was designed to investigate risk indicators for the occurrence of the birth defect craniosynostosis in Colorado. A total of 173 children who underwent craniectomy for craniosynostosis and 759 children without craniosynostosis were included in the study. Multivariable logistic regression analysis of birth certificate data showed that male sex (odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.1-2.2), maternal five-year age "increase" (OR = 1.3, 95% CI = 1.1-1.5), plural birth (OR = 3.0, 95% CI = 1.2-7.1) and black maternal race (OR = 0.0, 95 per cent CI = 0.0-0.6) were independently associated with craniosynostosis. There was a weak positive association between craniosynostosis and the altitude of the town closest to the maternal residence, but no association was found with maternal education, marital status, number of previous births, or previous pregnancy termination. The association of craniosynostosis with plural birth is consistent with the hypothesis of fetal head constraint.