Objective To explore the method for differentiation induction of leukemia cells into dendritic cells(DC) by A23187 in vitro. Methods Chronic myeloid leukemia K562 cells were cultured with A23187 or cytokine to induce differentiation and form DC. The morphologic features of cells were observed under inverted microscope, the changes of DC surface marks were determined by flow cytometry and RT-PCR, the ability to stimulate lymphocyte proliferation was tested by MTT colorimetry. Results Under the condition of the does (385 ng/ml) of A23187 for four days, some of K562 cells were found in typical dendritic appearance.The expression of DC markers CD1a,CD83 ,HLA-DR,CD86 and CD80 was 6.65 ±2.70,7.37 ±2.40,6.24 ±4.29, 21.60 ± 3.84, 18.52 ± 4.48 repectively, and increased obviously compared with the negative control group(2.80 ±0.52,1.85 ±0.56,2.25 ±0.47,6.69 ±0.83,9.96 ±3.53). The differences had statistical significance (P < 0.05). K562 cells derived from DC acquired the ability to stimulate lymphocyte proliferation.Conclusion A23187 can induce the leukemia cells differenntiation into activated DC-like cells rapidly.

Objective To explore colloidal gold method used to detect fecal occult blood tests(FOB)detection capability and establish the laboratory standard operation of detecting FOB limit of blank(LOB),limit of detection (LOD)and quantifica-tion limit (LOQ)according to the CLSI document《Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures;Approved Guideline-Second Edition》(EP17-A2),in order to reduce the false negative rate of the weakly positive samples,and to provide a way of quantitative detection for qualitative detection of colloidal gold method.Methods Detected series of solution of hemoglobin made of dissolved fresh whole blood with the ELISA kit of human free hemoglobin,and es-tablished the standard curve of detection of FOB with colloidal gold method.Detected the blank samples and a series of low concentration samples with the colloidal gold test strip of FOB and measured the color bands by the Nato Checker710.The quantitative results obtained were statistically analysised by SPSS 1 9.0 and calculated blank limit,detection limit and quanti-fication limit.Results The LOB,LOD and LOD were 99.01,340.48 and 354.9 ng/ml according to the methods in CLSI EP1 7-A2 ducument.Conclusion The detection limits established by CLSI EP1 7-A2 document was more scientific in j udge-ment positive or negative to FOB than which used naked eye and can meet the clinical laboratory and clinical doctor require-ment better.Clinical laboratories should be strictly in detection limits of reagents in order to ensure their effectiveness,and should be generaly to other tests based on colloidal gold method.