The ECG and transmembrane action potentials of the ventricular cells of 40 albino rabbits at various heart rates under natural breathing were simultaneously recorded. After statistical analysis of the records of 126 units, quantitative relationships between action potential durations (APDs) and heart rates were found and regression equations were obtained by linear regression. In order to eliminate the effect of heart rates on APDs, the correction formulas on APDs were also worked out. After correction the effect of sinus cycle length (SCL) on APDs could be eliminated.
This study has provided a practical method for the study of the effect of different agents on the APDs of ventricular cells under more natural condition. Though the regression equations and correction formulas can only be applied in rabbits under natural breathing, this method might be adopted to work out the corresponding regression equations and correction formulas for other experimental animals. Therefore it has practical significance in a rather broad field.
Our previous reports described the anti-arrhythmic and hypotensive actions of dauricine (Dau), an alkaloid isolated from Menispermum dauricum DC. In the present paper we made a study of its effects on isoproterenol and calcium-mediated dose-response relationships and on the electro-mechanical activity in cat papillary muscles, and compared its actions with those of tetrandrine and/or verapamil, propranolol, quinidine. The results obtained are summarized as follows.
| 1. | Dau 8 x 10-5 M shifted the isoprenaline dose-response curve to the right with decrease of its maximum effect, in which it resembled tetrandrine 10-5 M, verapamil 5 x 10-7 M, but differed from propranolol. |
| 2. | Dau, like tetrandrine and verapamil, showed dualism in calcium antagonism. |
| 3. | Effect of Dau on the electro-mechanical activity: It depressed and widened the R wave, prolonged R-T interval of the surface electrogram of cat papillary muscles, and its inotropic action was analogous to that of tetrandrine. Dau seemed to possess not only calcium antagonistic, but also “quinidine-like” action. |
20 patients with insulin-dependent diabetes mellitus have been grafted with short-term cultured islet tissue of several fetal pancreases intramuscularly (7 cases) and intraperitoneally (13 cases). After transplantation, all of them took specially prepared traditional Chinese medicine daily and except 7 recipients one dose of antihuman thymocyte globulin as immunosuppressive therapy. Before transplantation, their daily insulin requirements ranged from 40 to 84 u but diabetes was mostly not well controlled. After transplantation, all but one recipients had good transplanting effect. The daily insulin requirements of these 19 efficiently transplanted diabetics had been reduced by 30–90 % in comparison with those before transplantation, in 13 of which the daily insulin requirements had been reduced by more than 50% (5 cases more than 80 %), while their fasting plasma glucose levels, except a few, remained normal or even subnormal. In some patients the postprandial plasma glucose levels remained less than 150 mg/d1. 2 patients had become noninsulin-dependent for a short time. 19 successfully transplanted diabetics have been followed up for 2 –11 months after transplantation, and their islet grafts are all working well without any sign of rejection.