ABSTRACT
The objective of this work was to develop a bioassay to quantify the antiplatelet aggregation activity of hirudo for quality evaluation and control. Antithrombin activity of hirudo extracted by high temperature decoction was determined by thrombin titration. Antiplatelet aggregation activity of hirudo was determined through pharmacodynamic experiments in vitro and in vivo using a bioassay we developed for quantifying inhibition of platelet aggregation. Methodological investigation was carried out and the titers of 12 batches of hirudo samples were determined. During the experiment, the disposal of animals is in accordance with the ethical standards of animal experiments. The results showed that the antithrombin activity of hirudo decocted at high temperature decreased significantly and almost lost its activity. Hirudo inhibited platelet aggregation and results in vivo and in vitro were consistent. These assays were employed to test 12 batches of hirudo. The results demonstrated that the biopotency of 12 batches was 113.49, 96.13, 121.22, 127.33, 83.48, 108.72, 131.41, 127.95, 76.90, 126.27, 132.89 and 573.53 U·mg-1. The method was reliable and reproducible and can be used to assess the quality of hirudo.
ABSTRACT
The study is aimed to investigate the effect of lamivudine on growth and metabolism of three intestinal characteristic bacteria (namely, Bifidobacterium adolescentis, Escherichia coli and Shigella dysenteriae). The growth condition of the three bacteria was quantitatively evaluated by microcalorimetry with four characteristic parameters of the thermal power-time curves, including the growth rate constant (k), thermal power (p), time to peak (t) and calorific value (Q). The results showed that the IC50 value of lamivudine on B. adolescentis was 200 microg x mL(-1), and the IC50 values of lamivudine on S. dysenteriae and E. coli were higher than 3 000 microg x mL(-1) and 6 000 microg x mL(1), respectively. Therefore, lamivudine made different inhibitory effects on the three bacteria, in which the B. adolescentis was most susceptible to lamivudine. This work showed that taking lamivudine chronically is likely to affect the balance of good flora in the intestinal tract, and might increase endotoxin release, leading to inflammation and disease progression in hepatopathy.