Résumé
A simple,rapid and sensitive upconversion immunochromatographic assay(UICA) was developed to detect imidaclothiz using NaYF4:Yb,Er upconversion nanoparticles(UCNPs) labeled with anti-imidaclothiz monoclonal antibody. The amino-modified UCNPs were conjugated with anti-imidaclothiz monoclonal antibody to prepare the UICA strip,which could realize the quantitative detection of imidaclothiz using a fluorescence photometer with an external 980 nm laser source. The working conditions of the UICA were systematically optimized, and the sensitivity, specificity, precision and accuracy were assessed by the studies of cross-reactivity (CR), spiked recovery and validation with HPLC. Under the optimal conditions (pH 8. 0, 0.3 mol/L NaCl,2.5% methanol and 0.2% PEG2000), the UICA could be completed in 25 min for the detection of imidaclothiz. The half-maximal inhibition concentration (IC50), limit of detection (IC10) and linear range (IC10-IC90) were 97.37 ng/mL,26.30 ng/mL and 26.30-363.08 ng/mL, respectively. The UICA had no CR with the analogues of imidaclothiz except for imidacloprid. The average spiked recoveries were 71.8%-97.2% with the relative standard deviations of 0.7%-10.7% in the matrices of paddy water, soil,pear,peach,wheat,cucumber,tomato and rice. The detection results of UICA for the authentic paddy water and pear samples were consistent with that of high performance liquid chromatography (HPLC).
Résumé
<p><b>OBJECTIVE</b>To investigate the role of endothelin-1 and its receptors on hypertrophy or proliferation of cultured cardial cells.</p><p><b>METHODS</b>Cardiomyocytes and cardiac fibroblasts were isolated by trypsin digestion method, DNA and protein synthesis were measured by 3H-dexyribonucleotidethymine (3H-TdR) and 3H-Leucine (3H-Leu) incorporation, while protein content was measured by Bradford method. Atrial natriuretic peptide (ANP) mRNA expression of cardiomyocyte was measured by reverse transcripted-polymerase chain reaction. Selective endothelin (ET) receptor subtype antagonists BQ123 and BQ788 were used to block ET(A) receptors (ET(A)R) and ET(B)R respectively and to observe the effects of the two receptors during cardiac hypertrophy.</p><p><b>RESULTS</b>ET-1 significantly increased the 3H-TdR and 3H-Leu incorporation rate of cardiomyocytes and cardiac fibroblasts in a dose-dependent manner and increased protein content. Furthermore, ET-1 promoted the ANP mRNA expression of cardiomyocyte. ET(A)R antagonist remarkably blocked these effects, while ET(B)R antagonist had no obvious effect.</p><p><b>CONCLUSIONS</b>ET-1 can induce the hypertrophy for cardiomyocytes and the proliferation for cardiac fibroblasts. These effects are mediated by ET(A)R.</p>