ABSTRACT
Huperzine A is a potent,reversible,and blood-brain barrier permeable acetylcholinesterase irhibitor.The aim of this study was to compare the pharmacokinetics,tolerability,and bioavailability of two formulations with the established reference formulation of huperzine A in a fasting,healthy Chinese male population.This was a randomized,single-dose,3-period,6-sequence crossover study.The plasma concentrations of huperzine A were determined by liquid chromatography tandem mass spectrometry.Tolerability was assessed based on subject interview,vital sign monitoring,physical examination,and routine blood and urine tests.The mean (SD) pharmacokinetic parameters of the reference drug were Cmax,1.550 (0.528) ng/mL;t1/2,12.092 (1.898) h;AUC0-72h,17.550 (3.794) ng.h/mL.Those of the test formulation A and test formulation B were Cmax,1.412 (0.467),1.521 (0.608) ng/mL;t1/2,12.073 (2.068),12.271 (1.678) h;AUC0-72h,15.286 (3.434) ng.h/mL,15.673 (3.586) ng.h/mL.The 90％ confidence intervals for the AUC0-72h and Cmax were between 0.80 and 1.25.No adverse events were reported by the subjects or found with results of clinical laboratory test.The test and reference products met the regulatory criteria for bioequivalence in these fasting,healthy Chinese male volunteers.All three formulations appeared to be well tolerated.
ABSTRACT
The clinically applied value of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery using real-time myocardial contrast echo-cardiography (RT-MCE) combined with two-dimensional strain echocardiography was assessed.Twenty patients underwent intravenous RT-MCE by intravenous injections of Sono Vue before and after coronary artery bypass surgery. Two-dimensional images were recorded from the left ventricular four-chamber view, two-chamber view and the apical view before, and two weeks and three months af-ter coronary artery bypass surgery, and the peak systolic longitudinal strain was measured. The results showed that myocardial perfusion was significantly increased after coronary artery bypass surgery in about 71.6% segments. In the group that myocardial perfusion was improved, the peak systolic longitu-dinal strain three months after bypass surgery was significantly higher than that before operation [(-15.78±5.91)% vs (-10.45±8.31)%, P<0.05]. However, the parameters did not change in the group without myocardial perfusion improvement [(-10.33±6.53)% vs (-9.41±6.09)%, P>0.05]. It was con-cluded that whether or not the improvement of myocardial perfusion can mirror the recovery trend of regional systolic function, two-dimensional strain echocardiography can observe dynamic change of re-gional systolic function. The combination of myocardial perfusion with two-dimensional strain echocar-diography can more accurately assess the curative effectiveness of coronary artery bypass surgery.
ABSTRACT
This study evaluated the application of quantitative tissue velocity imaging (QTVI) in assessing regional myocardial systolic and diastolic functions in dogs with acute subendocardial ischemia. Animal models of subendocardial ischemia were established by injecting microspheres (about 300 μm in diameter) into the proximal end of left circumflex coronary artery in 11 hybrid dogs through cannulation. Before and after embolization, two-dimensional echocardiography, QTVI and real-time myocardial contrast echocardiography (RT-MCE) via intravenous infusion of self-made microbubbles, were performed, respectively. The systolic segmental wall thickening and subendocardial myocardial longitudinal velocities of risk segments before and after embolization were compared by using paired t analysis. The regional myocardial video intensity versus contrast time could be fitted to an exponential function: y=A-(1-exp-β-t), in which the product of A and β provides a measure of myocardial blood flow. RT-MCE showed that subendocardial normalized A.β was decreased markedly from 0.99±0.19 to 0.35±0.11 (P<0.05) in 28 left ventricular (LV) myocardial segments after embolization, including 6 basal and 9 middle segments of lateral wall (LW), 8 middle segments of posterior wall (PW) and 5 middle segments of inferior wall (IW). However, there was no statistically significant difference in subepicardial layer before and after embolization. Accordingly, the ratio of A.β of subendocardial myocardium to subepicardial myocardium in these segments was significantly decreased from 1.10±0.10 to 0.31±0.07 (P<0.05). Although the systolic wall thickening did not change 5 min after the embolization in these ischemic segments (29%+_3% vs 31%±5%, P>0.05), the longitudinal peak systolic velocities (Vs) and early-diastolic peak velocities (Ve) recorded by QTVI were declined significantly (P<0.05). Moreover, the subendocardial velocity curves during isovolumic relaxation predominantly showed positive waves, whereas they mainly showed negative waves before the embolization. This study demonstrates that QTVI can more sensitively and accurately detect abnormal regional myocardial function and post-systolic systole causedby acute subendocardial ischemia.