ABSTRACT
The study aims to develop a rapid, sensitive and specified method of liquid chromatography with heated electrospray ionization tandem mass spectrometry (LC-HESI/MS/MS) for simultaneous determination of amlodipine, benazepril and benazeprilat in human plasma using amlodipine-d4 and ubenimex as internal standards (ISs). Selected reaction monitoring (SRM) with heated electrospray ionization (HESI) was used in the positive mode for mass spectrometric detection. Analytes and ISs were extracted from plasma by simple protein precipitation. The reconstituted samples were chromatographed on a C18 (100 mm x 4.6 mm, 5 microm) column with mixture of methanol-acetonitrile-5 mmol.L- ammonium acetate-formic acid (30 : 30 : 40 : 0.1) as mobile phase at a flow rate of 0.6 mL.min-1. The standard curves were demonstrated to be linear in the range of 0.02 to 6.00 ng.mL-1 for amlodipine, 0.2 to 1,500 ng.mL-1 for benazepril and benazeprilat with r2>0.99 for each analyte. The lower limit of quantitation was identifiable and reproducible at 0.02, 0.2 and 0.2 ng mL-1 for amlodipine, benazepril and benazeprilat, respectively. The intra-day and inter-day precision and accuracy results were within the acceptable limit across all concentrations. The plasma samples were stable after four freeze-thaw cycles and being stored for 93 days at -20 degrees C. The method was applied to a pharmacokinetic study of a fixed-dose combination of amlodipine and benazepril on Chinese healthy volunteers.
ABSTRACT
<p><b>BACKGROUND</b>Gefitinib, a selective inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, has been approved effective in local advanced or metastatic non-small cell lung cancer (NSCLC), with the equivalent response rate to that of chemotherapy in Asian patients. Asian ethnicity, gender, smoking history, adenocarcinoma histology were remarkably associated with gefitinib response and survival. However, predictive factors of gefitinib response and survival are still unclear in Asian population. In this study, we retrospectively reviewed the data of 153 Chinese NSCLC patients who received a single agent of gefitinib with the purpose of identifying the potential predictive factors of gefitinib response and survival.</p><p><b>METHODS</b>Tumor response, survival and the clinicopathologic factors of 153 NSCLC patients treated between November of 2003 and June of 2004 were collected retrospectively from the multicenter clinical trial in China. Pearson Chi-square test and Logistic regression test were performed respectively as univariate and multivariate analyses of gefitinib response. Overall survivals between groups with different predictive factors were compared by log-rank tests. Multivariate analysis was performed to identify factors that independently predict for survival.</p><p><b>RESULTS</b>A total of 153 patients were included in this analysis. Objective response rate was statistically significant higher in patients with younger age (≤65 years) and longer interval from diagnosis to gefitinib treatment (≥6 months) in multivariate analysis (P < 0.05). The median follow-up duration was 10.0 months (0.5-16.8). The median survival was 10.3 months (95% CI: 8.1-12.6) and 1-year survival was 44.1%. Significant independent predictive factors associated with longer survival in multivariate analysis were good performance status (score 0-1), controlled disease (CR+PR+SD) to most recent chemotherapy and controlled disease to gefitinib (P < 0.05).</p><p><b>CONCLUSIONS</b>Gefitinib is effective in local advanced or metastatic NSCLC patients who failed to chemotherapy in Chinese population. In Chinese NSCLC population, younger age (≤65 years) and longer interval from diagnosis to gefitinib treatment (≥6 months) were predictive factors in multivariate analysis for gefitinib response; good performance status (score 0-1), controlled disease to most recent chemotherapy and controlled disease to gefitinib were independent prognostic factors for survival.</p>
ABSTRACT
Aim To purify L-amino acid oxidase(LAAO) from the venom of Naja atra and study its effect on endothelial cells.Methods The NAV-LAAO was purified by ion-exchange chromatography and affinity chromatography.The MTT assay and Western blot were used to detect the viability and apoptosis of HUVEC.The tubule-forming was used to study the angiogenesis of cells.Results The NAV-LAAO was purified successfully from the venom of Naja atra.The molecular weight of NAV-LAAO was determined to be 58 ku by SDS-PAGE.NAV-LAAO effectively inhibited the growth and tubule-forming of HUVEC,and the 50% inhibitory concentration(IC50) was 21.42 mg?L-1.Compared with control,the levels of caspase-3 and caspase-8 increased in HUVEC treated with NAV-LAAO.Conclusions The NAV-LAAO is purified successfully from Naja atra venom by ion-exchange chromatography and affinity chromatography.The NAV-LAAO inhibits the growth and tubule-forming capacity of HUVEC in a dose-dependent manner.