Exogenous Nkx2-5 gene expression induces the expression of cardiac markers during P19 cell differentiation in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of homeobox gene Nkx2-5 in cardiac myogenesis.</p><p><b>METHODS</b>Two P19 cell lines, namely cells transfected with exogenous expression of Nkx2-5 gene and non-transfected cells, were cultured in suspension for 4 days to induce cell aggregation, and the cell aggregates were transferred to the Petri dish for further adherent culture. On days 4, 8, 12 and 16 of adherent culture, the expressions of α-sarcomeric actin (α-SA) and cardiac troponin T (cTnT) protein were detected by immunocytochemistry, and the mRNA expressions of GATA-4, α-myosin heavy chain (α-MHC) and atrial natriuretic factor (ANF) genes by RT-PCR.</p><p><b>RESULTS</b>In the transfected cells, α-SA and cTnT protein expressions were detected on days 8, 12 and 16 of adhere culture, and their expressions increased gradually with time. α-SA and cTnT expression was significantly higher on day 16 than on day 8 of culture (P<0.01). RT-PCR analysis of the transfected cell showed the presence of GATA-4 expression on day 4 of adherent culture, and the expression increased on days 8 and 12 but decreased on day 16. ANF and α-MHC expressions were found on days 8, 12, and 16, increasing gradually over time and showing significant differences from those on day 4 (P<0.05 or P<0.01). The expression of α-MHC was significantly higher on days 12 and 16 than on day 8 (P<0.05 or P<0.01), and ANF expression was significantly higher on day 16 than on days 8 and 12 (P<0.01). The non-transfected cells were negative for the expressions of all these genes.</p><p><b>CONCLUSION</b>Exogenous expression of Nkx2-5 gene can induce P19 cells to express cardiac markers in vitro.</p>

Study on excretion of pseudo-ginsenoside GQ / 中国中药杂志

<p><b>OBJECTIVE</b>To determine the pseudo-ginsenoside GQ (PGQ) in rat bile, feces and urine, and to study on the excretion of pseudo-ginsenoside GQ.</p><p><b>METHOD</b>Reverse phase high-performance liquid chromatography (RP-HPLC) method with an evaporative light-scattering detector (ELSD) was performed on Diamonsil C18 column (4.6 mm x 250 mm, 5 microm), and the mobile phase was consisted of methanol-water (24: 7) with flow rate of 1.0 mL x min(-1). ELSD parameters were set as follows: nitrogen gas pressure 3.0 bar, drift tube temperature 50 degrees C.</p><p><b>RESULT</b>The method fulfilled all the standard requirements of precision, accuracy and linearity. The main way of excretion of PGQ in rat administrated through sublingual vein was at the bile. The bile excretion ratio of PGQ was 41.60%, and feces excretion ratio was 9.97%. Only trace amount of PGQ was excreted in urine.</p><p><b>CONCLUSION</b>Almost all unchanged PGQ was excreted in bile, feces and urine.</p>

LC-ESI-MS metabolic profiling analysis of taxanes from the extracts of Taxus chinensis cell cultures / 药学学报

<p><b>AIM</b>To develop a rapid analytical method for small amount biological samples of taxanes by using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS) in small amount biological samples.</p><p><b>METHODS</b>A solution containing five given taxane constituents and the extract from cell cultures of Taxus chinensis were analysed separately. According to the performance of the given taxanes in ESI-MS/MS, run parameters of the mass spectrometer were optimized. Positive and negative electrospray modes were employed to simultaneously scan the cell cultures sample, and the full ion chromatogram and the molecular weight of individual peak were obtained. The qualitative analysis of taxanes was achieved by comparison of the retention time and molecular weight with those of the reference substances or was based on the interpretation of the MS/MS spectra of the analytes and the knowledge of the concerning genetic backgrounds of taxanes published in literatures.</p><p><b>RESULTS</b>The taxanes with several acetyl substituents tended to produce ammonium adduct ions peak, while multi-hydroxy taxanes were subject to give protonized molecular ion peaks in positive ion ESI-MS. Thirteen taxanes in cell samples were assigned. Eight compounds of them were identified to be 1 -acetyl-5, 7, 10-deacetyl-baccatin I (DAB-I, 1) , baccatin III (B-III, 3), baccatin VI (B-VI, 8), taxol (9), yunnanxane (10 ), taxuyunnanine C (Tc, 11), sinenxane B (12), sinenxane C (13), separately. For the other five constituents, character of taxane and the number of substituents were deduced.</p><p><b>CONCLUSION</b>The results confirm the feasibility of characterizing taxanes in biological samples by LC-ESI-MS analysis. The analytical methodology provided a rapid, conventional and reliable tool to study metabolic profiling of taxanes for structural elucidation in taxol biosynthesis.</p>