Barbiturate dependence in mice: effects of continuous vs. discontinuous drug administration

Three groups of DBA/2J mice were continuously exposed for 3, 6 or 9 days to a milled diet containing phenobarbital. Two additional groups were given a discontinuous drug administration schedule with either one or two 24 h drug-free periods interpolated among the 6 or 9 days of phenobarbital consumption, respectively. The discontinuous schedule of drug administration significantly attenuated the development of physical dependence as determined by the severity of withdrawal symptoms. Functional tolerance development was also attenuated in a manner that closely paralleled the effects on physical dependence development. The 5 group means showed a perfect rank order correlation between functional tolerance and physical dependence development.

Controlled drug release from polymeric delivery devices. III: In vitro-in vivo correlation for intravaginal release of ethynodiol diacetate from silicone devices in rabbits

Forty female rabbits were implanted with silicone vaginal devices containing ethynodiol diacetate for up to 8 weeks. As predicted from in vitro studies, a Q - t1/2 (matrix-controlled) release profile was observed in vivo. The in vivo drug release profile was compared with in vitro data measured at three hydrodynamic conditions, and the diffusional resistance across the vaginal wall was estimated. Drug released from silicone devices yielded a prolonged plasma level when compared with data following intravaginal or intravenous administration of a solution dose. The rate constant for elimination was unchanged. The plasma concentration of the drug was related to the intravaginal drug release profile both theoretically and experimentally and was above the concentration required to inhibit fertilization.

The biological significance of mongolism

Professor Penrose turned his attention to the subject of mongolism at a very early stage in his professional career and retained an undiminished interest in all facets of the problem for more than 40 years. His first publication in this sphere was in 1931 (1) and was entitled ‘The creases on the minimal digit in mongolism’. The observations he made in this publication are typical of some of his later ones. It reflected a mind alert to useful detail, in this case the fact that in some mongols there is only one flexion crease on the fifth digit instead of two. This peculiarity rarely occurs in the normal population and therefore provides an additional diagnostic criterion for mongolism. Particularly at a time when chromosomal examination could not be undertaken, this direct simple observation helped in the clinical delineation of a condition which is not always easily recognized.

Temporary suppression of Streptococcus mutans in humans through topical application of vancomycin

Vancomycin, an antibiotic with desirable properties for oral usage, was applied in a 15% gel formulation to the teeth of children, and as a 1% paste to the teeth of young adults. Temporary suppression was observed in the presence of Streptococcus mutans, an organism which has been implicated in human dental caries.