[Apoptosis-inducing Effect of 8-Bromo-7-Methoxychrysin on K562 cells].

This study was purposed to investigate the apoptosis-inducing effect of 8-bromo-7-methoxychrysin (BrMChR) on leukemia K562 cells as well as the variation of caspase-3 activity and phosphorylated Akt (p-Akt) expression of K562 cells during the process of apoptosis. MTT assay was used to determine the inhibitory effect of BrMChR on proliferation of K562 cells. Cell apoptosis was assayed by AO/EB staining under fluorescent microscope and flow cytometry with Annexin V-FITC/PI staining.

[The effect of ATRA-induced leukemic cell differentiation on Brd7 gene expression in leukemia cell lines].

This study was purposed to investigate the relationship between brd7 gene and differentiation of leukemia cells and the role of brd7 gene in differentiation of leukemia cells. The HL-60 and K562 cell lines were induced by all-trans retinoic acid (ATRA) for 7 days, then the cell morphologic change was observed under inverted microscope with Wright-Giema staining, the expression level of CD11b was detected by flow cytometry for evaluating cell differentiation level, the expression changes of BRD7 protein before inducing differentiation and in process of cell differentiation were determined by Western blot. The results showed that ATRA could inhibit the proliferation and induce differentiation of HL-60 cells, but no differentiation in K562 cells was induced by ATRA.

[Expression and activity of glycosylphosphatidylinositol-specific phospholipase d mRNA in bone marrow mononuclear cells isolated from patient with acute myeloid leukemia and their significance].

This study was purposed to investigate the expression and significance of glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) in bone marrow mononuclear cells (BMMNC) isolated from patients with acute myeloid leukemia (AML), GPI-PLD activity in BMMNC isolated from 78 patients with AML and 15 normal persons was measured by using GPI-anchored placental alkaline phosphatase (PLAP) as a substrate and Triton X-114 phase partitioning. The GPI-PLD mRNA expression was measured by semi-quantitive reverse transcription-polymerase chain reaction (RT-PCR). The results showed that the mRNA expression level and activity of GPI-PLD in BMMNC from de novo AML patients were 1.

[In vitro differentiation into megakaryocytes and generation of platelets from CD34+ cells of umbilical cord blood].

Objective: To induce hematopoietic progenitor/stem cells of umbilical cord blood to differentiate into mature megakaryocytes and platelets in vitro and to investigate the mechanism of production of platelets.

Methods: The CD34+ cells were sorted from umbilical cord blood by magnetic activated cell sorting (MACS) and then cultured in vitro with optimized medium to be differentiated into mature megakaryocytes and platelets. The cultured cells and the platelet-like particles were isolated from the culture and were checked by the fluorescence-activated cell sorter (FACS), immunohistochemistry assays, light microscope,electron microscope and platelet aggregation tests.

Effects of integrin alpha IIb(R995A) mutation on receptor affinity and pp125 (FAK) phosphorylation.

Objective: To investigate the role of cytoplasmic domain of integrin alpha IIb in platelet signal transduction.

Methods: Binding capacity of integrin alpha IIb(R995A) to antibody platelet activation complex-1 (PAC-1) and pp125 focal adhesion kinase (FAK) phosphorylation of cells were detected by flow cytometry, immune precipitation, and Western blotting.

Results: Without activation, wild-type alpha IIb beta3 Chinese hamster ovary (CHO) cells failed to bind to PAC-1, but mutant chimera alpha IIb(R995A)beta3 CHO cells were able to bind with PAC-1.

[Effect of the defect of integrin alpha II b beta 3 on the inside-out signal transduction in platelets].

Objective: To investigate the effect of the defect of integrin alpha II b beta 3 on the inside-out signal transduction in platelets.

Methods: The transfected cDNA, its expression and the ability of cells binding to PAC-1 and fibrinogen were investigated by RT-PCR, DNA sequence analysis, flow cytometry and Western blotting.

Results: The integrin alpha II b beta 3 level in the patients with Glanzmann's thrombasthenia was significantly lower than that of the normal subjects and the platelets of the patients failed to bind PAC-1 activated by ADP.