[Blood-brain barrier. II. Kinetics of distribution of 3H-parahydroxyamphetamine in brain structures after intravenous administration in the rat]

Intravenously injected parahydroxyamphetamine hardly penetrates into the Central Nervous System, since, 5 minutes after injection, the tissue to plamsa concentration ratio for brain and cerebrospinal fluid amounts to 0,67 and 0,35 respectively. Its concentration in muscle is 5 times higher than in plasma. In the brain, the molecule is preferentialy taken up by the corpus striatum and the hypothalamus. Thus, parahydroxylation of amphetamine inhibits the penetration of the molecule into the brain and suppresses its cortical fixation. These characteristics could explain why this parahydroxylated amine has no psychotropic action.

Studies on the developmental cycle of Chlamydia trachomatis: isolation and characterization of the initial bodies

The initial bodies which develop in the inclusion bodies of trachoma agent (Chlamydia trachomatis) were separated from the infected cells nuclei and cytoplasmic components by zone centrifugation in sucrose gradients. The initial bodies are the site of the agent's ribonucleic acid synthesis and serve as precursors to the elementary bodies. The conversion of the initial bodies to elementary bodies is through a process which resembles binary fission. The effects of antibiotics on the development of the trachoma agent initial bodies revealed that rifampin prevented and hydroxyurea affected the formation of the initial bodies. Penicillin led to the formation of structures larger than the initial bodies.