Cigarette smoke condensates from all cigarettes tested were found to be potent inducers of AHH enzyme in cultured human lymphocytes and, with the exception of Kent Lights and Carlton CSC's, all were found to be toxic under the experiment conditions. Most of the AHH inducing activity was found in basic and neutral fractions of the lAl standard cigarettes. A radiometric assay of BP metabolites in cultured human lymphocytes was developed in which we were able to separate the primary metabolites and the secondary metabolites from the parent compound (BP) by neutral alumnia HPLC. The primary metabolites were further separated by a selective enzyme hydrolysis and/or reverse phase HPLC.

Purification of lipase from Pseudomonas aeruginosa (from both a washed cell suspension and crude culture supernatant as the enzyme source) was performed utilizing affinity chromatography. Affinity chromatography was carried out using n-dodecylamine bound to Sepharose 4B. Chromatography of the concentrated crude culture supernatant resulted in a 65 to 95 fold purification with 5.8% recovery. Washed cells collected from a ten hour culture suspended in water also produced enzyme. Activity of the washed cell suspension supernatant was found to be 4.5 fold higher than the activity of the culture supernatant. A thirty percent recovery was obtained using the washed cell suspension supernatant. The washed cell suspension provides a cleaner preparation for use with the dodecylamine-agarose chromatography in purifying the enzyme.

Thirty-one rats were trained on a differential reinforcement of low rate schedule. After responding had stabilized, animals were injected with methylphenidate, twice weekly, presession. Methylphenidate produced dose-dependent increases in response rates and decreases in reinforcements. Repetition of these doses produced a reduced drug effect, and a third administration of the 10 mg/kg dose further reduced the drug effect. Subsequently, the effects of daily and intermittent administration were determined for this dose. Daily methylphenidate, pre-session, produced tolerance to the behavioral effects of methylphenidate and cross-tolerance to the amphetamines. Twice-weekly methylphenidate, pre-session, produced partial tolerance to methylphenidate and partial cross-tolerance to the amphetamines. Thus, periodic exposure to the behaviorally disruptive effects of a drug of the amphetamine class reduces the effects of subsequent exposure.

Histidine-rich protein from newborn rat epidermis has been further characterized. Polyacrylamide gel electrophoresis in 8 M urea demonstrated dissociation of the protein, a possible oligomeric series, and one major band with two minor bands of the, pH 5.0 precipitate. Amino acid analysis correlated well with previous analyses (except for lower levels of histidine), while the amino acids of high content increased with purification. Sedimentation coefficients and molecular weights determined by ultracentribfugation of all monomers and the residual tissue in histidine-rich protein were in agreement with estimates from gel filtration chromatography. Lower values were obtained for keratohyalin granule proteins. Isoelectric focusing indicated diisoelectric properties of the protein. A molecular model of deamidation is presented in an attempt to explain this property.