The interaction of beta-cyclodextrin with etoposide studied by fluorescence spectroscopy / 药学学报

The fluorescence spectroscopy and UV spectroscopy have been used to monitor the inclusion phenomena of VP-16 with beta-cyclodextrin (beta-CD), together with studies concerning the effects of reaction time, temperature and concentration on this behavior. The results show that the fluorescence intensity increased when VP-16 and beta-CD forming a 1 : 1 inclusion complex, which indicate that beta-CD has fluorescence sensitizing effect on the VP-16. At 22 degrees C, the inclusion constant was 2.63 x 10(5) L x mol(-1) at pH 7.0. VP-16 has maximum emission wavelength at 316 nm under the optimum conditions. According to this, the quantitative micro-detection method of VP-16 by fluorescence spectrometry was established. The linear regression equation was y = 1.107 89 x 10(70 x + 95.898 1, with a correlation coefficient of 0.999 9. The detection limit was 2.094 x 10(-7) mol x L(-1).

The mechanism of JWA gene involved in oxidative stress of cells / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the mechanism of gene JWA involved in oxidative stress under hydrogen peroxide (H(2)O(2)) exposure.</p><p><b>METHODS</b>Both MCF-7 (human breast cancer cell line) and WI-38 (human embryo lung fibroblast cell line) cells were treated with 1 mmol/L of H(2)O(2) with or without pre-incubation of taurine (tau). Malondialdehyde (MDA) and glutathione (GSH) contents in supernatant of cell culture were measured; RT-PCR and Western blotting were carried out for evaluation of the expressions of JWA mRNA and protein respectively. Heat shock proteins (HSP27, HSP70 and HSP90) were also analyzed.</p><p><b>RESULTS</b>The contents of MDA before and after H(2)O(2) treatment in MCF-7 cells were (0.531 +/- 0.038), (0.674 +/- 0.410) mmol/L respectively, (P < 0.01), while those in WI-38 cells were (0.572 +/- 0.035), (0.683 +/- 0.028) mmol/L respectively, (P < 0.01). The contents of GSH before and after H(2)O(2) treatment in MCF-7 cells were (0.053 +/- 0.002), (0.044 +/- 0.002) g/L respectively, (P < 0.01), while those in WI-38 cells were (0.058 +/- 0.002), (0.050 +/- 0.002) g/L respectively, (P < 0.01). The expression of JWA mRNA was down regulated, at 6 h it decreased by 68.4%, while in WI-38 cells no obvious change found. JWA protein and HSP27 showed markedly increased after H(2)O(2) treatment in both cells but not in similar extent.</p><p><b>CONCLUSION</b>Oxidative stress signal pathways of JWA gene varied between cancer and non-cancer cell lines; JWA protein may have a similar function as HSP27 and act as an important signal molecule in H(2)O(2) induced cell injury.</p>