A rapid and sensitive method based on biotin-avidin mediated competitive enzyme-linked immu nosorbent assay(BA-ELISA) was established for the determination of ketamine.The optimal concentration of coated antigen and anti-ketamine monoclonal antibody were found to be 2.0 and 10.2 mg/L.The concentra tions of biotinylated goat anti-mouse IgG(Biotin-IgG) and streptavidin-horseradish peroxidase(SA-HRP) were optimized and the optimum results were found to be 0.29 and 1.0 mg/L, respectively.The linear range of the presented method was from 0.1 to 1000 μg/L, and the limit of detection was found to be 0.03 μg/L.The recoveries of ketamine spiked in human serum and urine were between 94% and 102%.Comparing the result of traditional ELISA, the present BA-ELISA method had a lower detection limit for ketamine.The experimental results indicated that the present BA-ELISA method was specific and sensitive.

Objective　To determine the ultrastructural localization of P-gp, p53 protein, and Bcl-2 protein in lung cancer cells,their relation to multidrug resistance and possible mechanisms of action.　Methods　Expression of P-gp, p53, and Bcl-2 proteins was examined in 8 NSCLC surgical specimens and 7 SCLC bronchoscopically biopsied specimens using postembedding PAG immunolabelling technique for electron microscopy.　Results　P-gp was detected on the cell membrane and the periphery of endoplasmic reticulum(ER). P53 protein was observed not only in the nuclei associated with heterochromatin but also in the cytosol. Bcl-2 protein immunoreactivity was associated with mitochondria and ER. P-gp, p53, and Bcl-2 were detected in 5(33%), 9(60%), and 4(26.7%) out of the 15 samples examined，respectively. In 8 normal lung tissues, these three proteins were detected. Of 5 P-gp positive samples 4 were NSCLC, only 1 was SCLC after chemotherapy.　Conclusion　P-gp, p53, and Bcl-2 proteins are detectable immuno-electron microscopically in lung cancer cells. No correlation in expression existed between of p53 and P-gp, nor did that between p53 and Bcl-2. The plasma membrane localization of P-gp supports its action as a transmembrane drug efflux pump. P-gp may play a role in MDR in lung cancer.

Objective　To determine the ultrastructural localization of P-gp, p53 protein, and Bcl-2 protein in lung cancer cells,their relation to multidrug resistance and possible mechanisms of action.　Methods　Expression of P-gp, p53, and Bcl-2 proteins was examined in 8 NSCLC surgical specimens and 7 SCLC bronchoscopically biopsied specimens using postembedding PAG immunolabelling technique for electron microscopy.　Results　P-gp was detected on the cell membrane and the periphery of endoplasmic reticulum(ER). P53 protein was observed not only in the nuclei associated with heterochromatin but also in the cytosol. Bcl-2 protein immunoreactivity was associated with mitochondria and ER. P-gp, p53, and Bcl-2 were detected in 5(33%), 9(60%), and 4(26.7%) out of the 15 samples examined，respectively. In 8 normal lung tissues, these three proteins were detected. Of 5 P-gp positive samples 4 were NSCLC, only 1 was SCLC after chemotherapy.　Conclusion　P-gp, p53, and Bcl-2 proteins are detectable immuno-electron microscopically in lung cancer cells. No correlation in expression existed between of p53 and P-gp, nor did that between p53 and Bcl-2. The plasma membrane localization of P-gp supports its action as a transmembrane drug efflux pump. P-gp may play a role in MDR in lung cancer.