Treatment of premenstrual dysphoric disorder with sertraline during the luteal phase: a randomized, double-blind, placebo-controlled crossover trial.

BACKGROUND: The authors designed a randomized, double-blind, crossover study to assess the efficacy of sertraline in the treatment of premenstrual dysphoric disorder (PMDD) when given only during the luteal phase of the menstrual cycle. METHOD: Thirty-one subjects were selected for a 7-month study period that included an initial 2 months of screening, 2 months of treatment with placebo or sertraline, 1 washout month, and 2 months of crossover treatment with either placebo or sertraline. Eleven subjects completed the study. Symptoms were monitored with daily reports using the Calendar of Premenstrual Experience (COPE). For each study phase, premenstrual COPE scores (7 days prior to menses) were examined using repeated measures analysis of variance. Scores were logarithmically transformed. Comparison of baseline scores between the luteal and follicular phases was examined using the paired t test. RESULTS: Analysis of COPE results during the treatment periods of the luteal phase showed a significant treatment effect, with higher scores during the placebo cycles compared with the sertraline-treated cycles (p = .0052 behavioral, p = .014 physical). CONCLUSION: This study is the first to demonstrate a significant response to a serotonin selective reuptake inhibitor used only during the luteal phase. The authors point out the importance of this finding both in terms of economic cost of patients as well as how it may add to the growing understanding of the etiology of PMDD.

Creatinine, lactam and cyclic peptide formation by the action of C2N2 on creatine, omega-amino acids and peptides.

Cyanogen, C2N2, affords a means to drive intramolecular conversion of ammonium salts to amides. Unlike other carboxyl activating agents, such as carbodiimides, used in peptide syntheses expressly to drive intermolecular condensations to form amide (peptide) bonds, C2N2 appears restricted to driving only intramolecular condensations. Rates decreased as a function of solvent composition as follows: organic much greater than 70%-80% aqueous organic much greater than 50% aqueous organic greater than H2O. Temperature dependence was also a function of solvent composition. Rates did not strongly reflect steric constraints with beta-lactams and epsilon-lactams forming at comparable rates to rates for gamma- and delta-lactam formation; likewise L-Leu-L-Leu cyclized at about the same rate as L-Leu-D-Leu. Pro-Pro is well documented as having a salt-bridged structure in a variety of solvents where it cyclized extremely rapidly. The reaction is proposed to be dependent on reaction of C2N2 with salt-bridges on the basis of 1) its preponderant if not exclusively intramolecular nature, 2) its solvent dependence, 3) its temperature dependence and 4) the conversion of known salt-bridged structures to amides. This reaction is a model for the observed rapid reaction of salt bridges in proteins.

Quantitative effects of respired helium and oxygen mixtures on gas flow using conventional oxygen masks.

A model lung system with a variable artificial constriction was used to quantify the changes in flow produced by the addition of helium to the gas mixture in the system. The tracheal concentration of helium obtained when administering 79% helium/21% oxygen to the system via conventional, disposable face masks was determined using a resuscitation dummy. The greatest proportion of the increase in flow through the orifice occurred at concentrations of helium up to 40%. A tracheal concentration of 40% helium could be obtained with all oxygen masks at fresh gas flow rates greater than 8 litres/minute. These findings will help to rationalise the administration of 79% helium/21% oxygen to patients with upper respiratory tract obstruction.

The genetic control of the molybdoflavoproteins in Aspergillus nidulans. IV. A comparison between purine hydroxylase I and II.

The purine hydroxylases I and II of Aspergillus nidulans [previously called xanthine dehydrogenases I and II: Scazzocchio, Holl and Foguelman, Eur. J. Biochem. 36, 428--445 (1973)] have been studied in crude extracts. The two enzymes differ in their substrate specificities, purine hydroxylase II being able to accept nicotinate as a substrate and unable to hydroxylate xanthine. The kinetics of inhibition with allopurinol and oxypurinol are also different, the two analogues being pseudo-irreversible inhibitors of purine hydroxylase I, while allopurinol is a competitive inhibitor of purine hydroxylase II and oxypurinol shows anti-competitive inhibition. Differences in electro-phoretic mobility and molecular size are also shown. We have failed to show the formation of hybrid purine hydroxylase I/II molecules. While a common evolutionary origin of the purine hydroxylases could be postulated, the data reveal a considerable divergence.