ABSTRACT
Both enantiomers of quinacrine and the racemic form of the drug showed equal activity in vitro against chloroquine-sensitive and -resistant strains of Plasmodium falciparum, without detectable stereoselectivity. This contrasts with observations on chloroquine, where a similar lack of stereoselectivity in vitro is accompanied by a 10-fold loss of activity against the resistant strain. The observed in vivo differences reported for the enantiomers of chloroquine and the observations on the optically active metabolites of chloroquine and quinacrine may therefore be ascribed to a difference in the pharmacokinetics of their enantiomers.
Subject(s)
Antimalarials/pharmacology , Plasmodium falciparum/drug effects , Quinacrine/pharmacology , Animals , Chloroquine/pharmacology , Drug Resistance/genetics , Plasmodium falciparum/genetics , Quinacrine/pharmacokinetics , StereoisomerismABSTRACT
Enzymic hydroxylation of 4-ethylphenol by (a) Pseudomonas putida and (b) highly purified p-cresol methylhydroxylase gave optically active 1-(4'-hydroxyphenyl)-ethanol. The products were transformed into the phenolic methyl ethers and shown to contain 69.5% and 65.6%, respectively, of the (S)-(-)-isomer. The stereochemistry of the reaction is discussed in terms of three distinct steps occurring at the active site of the enzyme.
Subject(s)
Ethanol/analogs & derivatives , Mixed Function Oxygenases/metabolism , Phenols/metabolism , Phenylethyl Alcohol/analogs & derivatives , Hydroxylation , Molecular Conformation , Phenylethyl Alcohol/metabolism , Pseudomonas/metabolism , StereoisomerismABSTRACT
High kilovoltage technique in chest radiography increases the visualization of the air-soft tissue boundaries of the mediastinum. The pulmonary-soft tissue interfaces account for pre- and paravertebral lines. The paravertebral and pleural-azygos-esophageal, central, posterior, and anterior lines of pleural contact are described, and displacement, deformities, and separation of the pleural reflections are illustrated.
