Origin of the Thymidine Kinase Induced by Polyoma Virus in Productively Infected Cells

Cells of the 3T3 mouse line efficiently supported the multiplication of polyoma virus, and the infectious process was accompanied by a marked increase in thymidine kinase (TK) activity. Two lines of 5-bromodeoxyuridine-resistant 3T3 cells have been isolated. As expected, these cells incorporated practically no exogenous thymidine into their deoxyribonucleic acid (DNA) and contained negligible TK activity. Like the parental 3T3 cells, TK(-) lines were susceptible to productive infection by polyoma virus, but infection did not lead to an increase in TK activity. Since kinase activity did appear after infection with another virus (vaccinia) known to contain the gene(s) for that enzyme, it is concluded that TK is not one of the gene products of polyoma virus. As induction of cellular DNA synthesis by polyoma virus occurs normally when the TK(-) cells are infected in the stationary phase, TK cannot play a role in the determination of this phenomenon.     

A Tranquilizer-Anticholinergic Preparation in Functional Gastrointestinal Disorders: A Double-Blind Evaluation

Chlordiazepoxide plus clidinium bromide (Librax®) was evaluated and compared with a placebo by means of a random sample, double-blind crossover technique in 42 patients presenting ordinary functional gastrointestinal disorders.Results:• 73.9 percent excellent-to-good response to the active drug in patients receiving it before they received the placebo, compared with 44.5 percent in those who did not receive it until after the placebo period.• 58.9 percent excellent-to-good response to the active drug in patients who received it after the placebo period, as compared with 31.8 percent in those receiving the placebo last.• Overall clinical response 67.5 percent excellent-to-good with the active drug as compared with 37.5 percent with the placebo.• Excellent-to-good results in 12 follow-up patients receiving the known active drug.• Statistically significant symptomatic response in four of eight target symptoms.The tranquilizer-anticholinergic preparation used appeared to improve not only patient outlook and attitudes but to effectively relieve both the physiologic and psychic manifestations of common functional gastrointestinal disorders.     

Plasma Digoxin Concentrations in Patients with Atrial Fibrillation

Plasma digoxin concentrations were measured by radioimmunoassay in 116 patients with atrial fibrillation on long-term oral treatment with the drug, and in 23 patients with digoxin toxicity. The mean concentrations were 1·4 ng./ml. and 3·1 ng./ml., respectively. Though an overlap occurred between the therapeutic and toxic ranges, toxicity is unlikely to occur below a level of 2 ng./ml. Plasma concentration showed a poor correlation with resting heart rate during atrial fibrillation. In patients with good renal function, however, a significant correlation was found between oral dose and plasma concentration. No evidence was obtained for increased sensitivity to therapeutic concentrations of the drug in elderly subjects, but the doses required to achieve these concentrations tended to be less than in younger patients.     

Spectral Studies of Iron Coordination in Hemeprotein Complexes: Difference Spectroscopy below 250 mμ

In order to evaluate the feasibility of observing the spectral behavior of protein groups in the coordination sphere of the iron in hemeproteins, criteria are developed to determine whether or not the application of difference absorption spectroscopy to the study of complex formation will be successful. Absolute absorption spectra, 300-1100 mmu, from bacterial catalase complexes are displayed, and the infrared bands correlated with magnetic susceptibility values of similar complexes of other hemeproteins. Dissociation constants for the formation of cyanide and azide complexes of metmyoglobin, methemoglobin, bacterial catalase, and horseradish peroxidase are given. Difference spectra, 210-280 mmu, are displayed for cyanide and azide complexes of these hemeproteins. A band at 235-241 mmu is found in the difference spectra of all low-spin vs. high-spin complexes. The factors which favor the assignment of this band to a transition involving a histidine residue are presented.