Effect of pentisomide (CM 7857) on myocardial excitation, conduction, repolarization, and refractoriness. An electrophysiological study in humans

The electrophysiological effects of pentisomide upon the intact human heart were evaluated using programmed stimulation and recording of intracardiac monophasic action potentials (MAP) in 17 patients with various ventricular arrhythmias. After i.v. administration of pentisomide, 85-135 mg, the atrial-His interval increased by 8 +/- 12 ms (p less than 0.05) during sinus rhythm and by 13 +/- 21 ms (p less than 0.05) at atrial pacing of 600 ms cycle length (600 ms pacing). The His-ventricular interval also increased by 6 +/- 10 ms during sinus rhythm (p less than 0.05) and by 5 +/- 9 ms at 600 ms pacing (NS). The QRS duration prolonged by 9 +/- 10 ms (p less than 0.01) and 6 +/- 8 ms (p less than 0.01) during 600 and 500 ms ventricular pacing, respectively. The right ventricular MAP duration to 90% repolarization was significantly shortened, by 20 +/- 21 ms (p less than 0.01) during sinus rhythm, by 16 +/- 17 ms (p less than 0.01) at 600 ms ventricular pacing, and by 11 +/- 16 ms (p less than 0.01) at 500 ms ventricular pacing. The corrected QT interval was shortened by 21 +/- 28 ms (p less than 0.01). The present study supports that pentisomide is a class-I antiarrhythmic agent with a marked effect on depolarization (action of class Ia and Ic) and on repolarization (action of class Ib). This unique combination of cellular electrophysiological properties indicates that the clinical antiarrhythmic efficacy of pentisomide may differ from that of hitherto available antiarrhythmic drugs.

Measurement of the refractive index and thermal refractive index coefficients of Nd:YAP crystal

The principal refractive indices of yttrium aluminate crystal doping with 1-wt.% neodymium (Nd:YAP) have been measured by a minimum deviation method for the wavelengths 0.5398, 0.6328, and 1.0795 microm in the temperature range of 289-435 K. The thermal refractive index coefficients have been obtained at these wavelengths, and they are all positive and slightly decrease with increased wavelength. The constants of the single term Sellmeier equation are also given for the 273-420 K temperature range. These constants are in linear relationship with temperature in the 4 x 10(-3) error range.

The genetic polymorphism of complement component C81 (alpha-gamma) in two Chinese populations

The genetic polymorphism of the complement component C81 (alpha-gamma) in two Chinese populations (Beijing and Guangzhou) were investigated, using isoelectric focusing followed by an immunoblotting technique. Three common and two rare phenotypes were observed. The homozygote phenotype C81 A1 ascribed to a rare allele C81*A1 was newly detected. The frequencies calculated for the two common alleles were as follows: C81*A = 0.5674, C81*B = 0.4255 for the Beijing population; C81*A = 0.5117, C81*B = 0.4785 for the Guangzhou population. The gene frequencies of the two common alleles of C81 in both Chinese populations were similar to those for the other ethnic groups thus far reported, and there is no statistically significant difference between the Beijing and the Guangzhou populations.