青蒿琥酯皮肤擦剂在小鼠和兔体内的药代动力学研究

将青蒿琥酯溶于苯二甲酸二甲酯,加适量氨酮制成皮肤擦剂。给兔脱毛后,皮肤涂抹此擦剂25mg/kg后,血药浓度达峰时间平均为2 h,峰浓度平均为1.80μg/ml。药物在兔体内平均驻留时间为3.54 h,清除半衰期约为2.46 h。给小鼠脱毛皮肤涂抹擦剂6.7,31.3和71.4 mg/kg,血药浓度在给药后0.5～4 h达高峰,峰浓度分别为0.82,2.05和7.11μg/ml,体内药物平均驻留时间为3.39,2.79及3.54 h,清除半衰期为2.35,1.93及2.45 h。可见,给兔及小鼠皮肤擦剂后,青蒿琥酯吸收良好,血药浓度维持时间较长。     

Mediation by B1 and B2 receptors of vasodepressor responses to intravenously administered kinins in anaesthetized dogs.

1. Vasodepressor responses to intravenous (i.v.) injection of bradykinin (BK) and des-Arg9-BK, a selective B1 kinin receptor agonist, were characterized following i.v. pretreatment with selective B1 ([Leu8]-des-Arg9-BK) and B2 (Hoe 140) kinin receptor antagonists in anaesthetized dogs. 2. Des-Arg9-BK (0.05-3.3 nmol kg-1) produced dose-dependent decreases in mean arterial blood pressure with a ED50 0.4 nmol kg-1. The vasodepressor effects evoked by des-Arg9-BK (0.6 nmol kg-1) and BK (0.2 nmol kg-1) were greater after i.v. and i.a. injections, respectively. 3. The vasodepressor response to BK (0.6 nmol kg-1) but not to des-Arg9-BK (0.6 nmol kg-1) was significantly (P < 0.001) blocked by pretreatment with the B2 receptor antagonist, Hoe 140. 4. The vasodepressor response to des-Arg9-BK (0.6 nmol kg-1) but not to BK (0.6 nmol kg-1) was significantly (P < 0.001) reduced by pretreatment with the selective B1 receptor antagonist, [Leu8]-des-Arg9-BK. Although both B1 and B2 receptor antagonists caused a transient fall in blood pressure, their inhibitory action was unlikely to be related to a desensitization mechanism. 5. Inhibition of prostaglandin synthesis with indomethacin prevented the vasodepressor response induced by arachidonic acid (1 mg kg-1, i.v.) but not that to BK or des-Arg9-BK (0.6 nmol kg-1). 6. These results suggest, firstly, that the vasodepressor responses to i.v. BK and des-Arg9-BK are mediated by the activation of B2 and B1 receptors, respectively; secondly, that prostaglandins are not involved in the vasodepressor responses to kinins.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epicardial distribution of ST segment and T wave changes produced by stimulation of intrathoracic ganglia or cardiopulmonary nerves in dogs

Sixty-three ventricular epicardial electrograms were recorded simultaneously in 8 atropinized dogs during stimulation of acutely decentralized intrathoracic autonomic ganglia or cardiopulmonary nerves. Three variables were measured: (1) isochronal maps representing the epicardial activation sequence, (2) maps depicting changes in areas under the QRS complex and T wave (regional inhomogeneity of repolarization), and (3) local and total QT intervals. Neural stimulations did not alter the activation sequence but induced changes in the magnitude and polarity of the ST segments and T waves as well as in QRST areas. Stimulation of the same neural structure in different dogs induced electrical changes with different amplitudes and in different regions of the ventricles, except for the ventral lateral cardiopulmonary nerve which usually affected the dorsal wall of the left ventricle. Greatest changes occurred when the right recurrent, left intermediate medial, left caudal pole, left ventral lateral cardiopulmonary nerves and stellate ganglia were stimulated. Local QT durations either decreased or did not change, whereas total QT duration as measured using a root-mean-square signal did not change, indicating the regional nature of repolarization changes. Taken together, these data indicate that intrathoracic efferent sympathetic neurons can induce regional inhomogeneity of repolarization without prolonging the total QT interval.     

Contribution of glucose tolerance and plasma insulin levels to the relationships between body fat distribution and plasma lipoprotein levels in women.

Numerous interrelated metabolic and morphological variables such as plasma insulin levels, glucose tolerance and abdominal obesity are associated with changes in plasma lipoprotein levels. The present study was undertaken to differentiate, using a multivariate approach, the respective contributions of plasma glucose and insulin levels, obesity and regional adipose tissue distribution to the variance in plasma lipoproteins. The study group was composed of 69 healthy premenopausal women (age 35.4 +/- 5.0 years (mean +/- s.d.); percent body fat 40.7 +/- 10.1). Indices of carbohydrate metabolism showed significant univariate correlations with triglyceride (TG) and/or cholesterol (CHOL) content of plasma VLDL, LDL and HDL (P less than 0.05). Multivariate analyses indicated that the explained variance in plasma VLDL-TG (R2 x 100 = 44 percent, P less than 0.05) and LDL-apoprotein (apo) B levels (R2 x 100 = 33.1 percent, P less than 0.08) was entirely accounted for by indices of carbohydrate metabolism and body fat distribution, whereas total body fatness added no significant contribution to these models. Multivariate analyses also revealed that the best possible regression model to predict the variation in plasma HDL2-CHOL levels only included computed tomography-derived deep abdominal adipose tissue area (P less than 0.0001). All other variables were unable to further improve the explained variance in plasma HDL2-CHOL levels. In partial correlation analyses, indices of carbohydrate metabolism and the waist-to-hip circumference ratio (WHR) remained significantly correlated with plasma VLDL-TG and LDL-apo B levels after adjustment of VLDL-TG and LDL-apo B for either insulin and glucose levels, or for the WHR (P less than 0.08). After correcting for deep abdominal fat accumulation, no significant correlation was observed between indices of carbohydrate metabolism and plasma HDL2-CHOL levels whereas deep abdominal fat showed significant correlations with HDL2-CHOL levels (P less than 0.05) after correction for indices of carbohydrate metabolism. These results suggest that both disturbances in glucose-insulin homeostasis and abdominal obesity are significantly associated with changes in plasma VLDL-TG and LDL-apo B levels and that these associations are partly independent from each other. These results also indicate that mechanisms other than disturbances in glucose homeostasis and hyperinsulinemia are responsible for the association between the level of deep abdominal fat and plasma HDL2-CHOL levels.