A simple quantitative method for the determination of 3-fluorotyrosine substitution in proteins

A rapid quantitative method is described for determining 3-fluorotyrosine incorporation into proteins. Derivatives of tyrosine and 3-fluorotyrosine with o-phthalaldehyde are well separated from one another by a reverse-phase high-performance liquid chromatography system used for routine analyses of o-phthalaldehyde-amino acid derivatives. Since both amino acids are well resolved from all other derivatized amino acids, the method is useful for amino acid analyses of proteins. Determination of the fluorotyrosine content of proteins by this method involves a single separation step, is reproducible, and requires no corrections for stability or yield. Further, the o-phthalaldehyde derivatives of 5-fluorotryptophan, 2-fluorophenylalanine, 3-fluorophenylalanine, and 4-fluorophenylalanine can also be resolved. The method may be generally applicable to fluorinated aromatic amino acid-labeled proteins that are studied structurally and dynamically by nuclear magnetic resonance.

Differing degrees of susceptibility to experimental allergic encephalomyelitis among inbred strains of hamsters

Susceptibility to experimental allergic encephalomyelitis was examined in five highly inbred strains of hamsters. The frequency of disease was reproducible within a given strain, but differed remarkably from strain to strain. Two strains--Bio 15.16 and Bio 87.20--appeared to share similar major histocompatibility genes. Despite genetic similarities, susceptibility to acute paralytic EAE was remarkably different in the two strains. Strain 15.16 hamsters consistently developed acute paralysis 10-21 days after sensitization with heterologous nervous tissue and immunologic adjuvants. Strain 87.20 hamsters never developed disease acutely. Protection from EAE was not absolute, however, for some animals developed histopathologic evidence of EAE. Using alternative methods to induce EAE did not alter susceptibility in 87.20 hamsters. Genetic analysis of offspring of susceptible 15.16 and resistant 87.20 hamsters suggested that a single autosomal gene, unrelated to the major histocompatibility locus, accounted for differences in EAE susceptibility in these two strains. This gene had a more profound influence on clinical patterns of EAE than on histopathologic markers of disease.

Neuroticism and extraversion of female homosexuals

Analysis of whether differing sex-object choices by 46 female heterosexuals and 46 female homosexuals are associated with significant differences in scores on the Eysenck Personality Inventory indicated heterosexual women were higher on the Neuroticism scale. No differences were found on the Lie or Introversion/Extraversion scales. Neither group scored above or below what is considered to be normal T-ranges of 30 to 70 on any scale.

Fluorinated ligands as nuclear magnetic resonance probes of active-site nonequivalence in abortive ternary complexes of horse liver alcohol dehydrogenase

The interactions of the dimeric horse liver alcohol dehydrogenase (LADH) with ligands in two nonreactive ternary complexes have been examined by using nuclear magnetic resonance and fluorescence techniques. One complex contains the enzyme, NADH, and the abortive alcohol substrate p-(trifluoromethyl) benzyl alcohol. The trifluoromethyl group allows the bound environment and bound to free exchange kinetics of this alcohol to be examined by using 19F NMR. Binding isotherms of the coenzyme and the abortive substrate were examined by using fluorescence. Similar measurements were made with the enzyme, NADH, and the aldehyde analogue p-(trifluoromethyl) benzamide. For both complexes there was no evidence of cooperative equilibrium binding of any ligand. Careful measurements of the exchange kinetics of the fluorinated alcohol or amide when binding to the enzyme NADH complex using NMR techniques showed that a single lifetime describes the exchange of ligands from both subunits of the protein. These results appear to rule out any site-site interactions in this system and support the notion that the observed biphasic kinetics observed in transient reactions of LADH with NAD and alcohols is a property of a single site in this system.

Phase I study of ftorafur, an analog of 5-fluorouracil

Ftorafur, a furanyl analog of 5-fluorouracil (5-FU), is reported to be five to six times less toxic and possibly more effective in cancer of the breast and colon than 5-FU. The drug was synthesized, formulated, and utilized in toxicologic studies, and then in 24 patients with advanced incurable malignancies. When Ftorafur is given by intravenous push, it results in immediate flushing, dizziness, nausea, retching, and in some cases transient hypotension. These immediate side effects are largely eliminated by administering the drug slowly by infusion. In patients, 60 mg/kg of Ftorafur given i.v. daily for up to 10 days resulted in mild toxicity. However, 80 mg/kg given i.v. daily for 7 days resulted in severe toxicity, with nausea, vomiting, stomatitis, leukopenia, and thrombocytopenia. These studies confirm those of the Russian investigators as to toxicity and dosage, even with a different method of administration more convenient for therapy. Phase II studies are presently being carried out to compare the effectiveness of Ftorafur and 5-FU.

Personality characteristics of female homosexuals

Several writers have suggested that female homosexuals have personality profiles that differ from those of female heterosexuals, but these profiles are not pathological in nature. This hypothesis was tested on 46 “normal” female homosexuals using the California Psychological Inventory, Eysenck Personality Inventory, and Edwards Personal Preference Schedule. There was only a slight personality pattern difference between the groups and neither group showed a pathological personality patttern.