Type 1 and type 2 T-cell profiles in idiopathic thrombocytopenic purpura.

Background And Objectives: Adult idiopathic thrombocytopenic purpura (ITP) is a chronic acquired organ-specific autoimmune hemorrhagic disease characterized by the production of antibodies against antigens on the membranes of platelet, resulting in enhanced Fc-mediated destruction of the platelets by macrophages in the reticuloendothelial system. Dysfunctional cellular immunity is considered important in the pathophysiology of ITP. The aim of this study was to explore the profile of type1 and type2 T cells in chronic ITP patients.

Production of a monoclonal antibody against SARS-CoV spike protein with single intrasplenic immunization of plasmid DNA.

Severe acute respiratory syndrome (SARS) is a highly infectious disease caused by a novel coronavirus (SARS-CoV). Specific monoclonal antibodies (mAbs) against the SARS-CoV are vital for early diagnosis and pathological studies of SARS. Direct intrasplenic inoculation of plasmid DNA encoding antigen is an effective and fast approach to generate specific mAb when the protein antigen is difficult to prepare or dangerous in use.

Multi-dysfunctional pathophysiology in ITP.

Idiopathic thrombocytopenic purpura (ITP) is an organ-specific autoimmune disorder characterized by a low platelet count and mucocutaneous bleeding. The decrease of platelets is caused by increased autoantibodies against self-antigens, particularly IgG antibodies against GPIIb/IIIa. The production of these autoantibodies by B cells depends on a number of cellular mechanisms that form a network of modulation, with T cells playing a pivotal role in pathophysiology.

Kinetic expression of platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) during embryonic stem cell differentiation.

Platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) is widely used as a marker during vasculogenesis and angiogenesis from embryonic stem (ES) cells. However, the expression of PECAM-1 isoforms in ES cells has not been determined. The present study was designed to determine the role of PECAM-1 isoforms during in vitro endothelial differentiation of ES cells.

Bone marrow stromal cells transduced with human hemangiopoietin gene support hematopoiesis in vitro.

Background And Objectives: The aim of this study was to construct a eukaryotic expression vector containing human hemangiopoietin (hHAPO) gene and express it in mouse bone marrow stromal cell line HESS-5, then support hematopoiesis in vitro with gene-modified HESS-5 (hHAPO-HESS-5).

Design And Methods: The polymerase chain reaction (PCR) products of HAPO were digested with BamHI and BgII. Then the HAPO gene segment obtained was again cloned into pIRES2-EGFP to construct recombinant eukaryotic expression vector HAPO-pIRES2-EGFP.

Comparison of cell-suspension and explant culture of rabbit limbal epithelial cells.

Currently, most investigators directly use limbal explants to culture corneal epithelial cells. However, it has not been identified that limbal stem cells do readily migrate from the limbal explants onto culture plate or amniotic membrane carrier. In this study a cell-suspension culture system for rabbit limbal stem cells was developed and compared with the direct explant method in the aspect of stem cells content in the culture system.

Survivin and leukemia.

Survivin is a unique member of the inhibitor-of-apoptosis family. Survivin plays a role in the proliferation and survival of normal hematopoietic cells. Survivin expression is aberrantly enhanced in most cancers and hematopoietic malignancies.

Early down-regulation of Bcl-xL expression during megakaryocytic differentiation of thrombopoietin-induced CD34+ bone marrow cells in essential thrombocythemia.

Background And Objectives: Essential thrombocythemia (ET) is a chronic myeloproliferative disorder with abnormal megakaryocyte/platelet production. Recent studies have found that Bcl-xL, as a member of the bcl-2 family of proteins that inhibit apoptosis, is essential in megakaryocytic differentiation. In this study the expression of Bcl-xL was evaluated during megakaryocytic differentiation in ET patients.

Reversal of P-glycoprotein-mediated multidrug resistance with small interference RNA (siRNA) in leukemia cells.

The multidrug resistance (MDR) mediated by P-glycoprotein (P-gp), the MDR1 gene product, is one of the major obstacles in leukemia treatment. The present study was designed to explore a MDR1-targeted small interfering RNA (si-MDR1) approach for reversal of P-gp-mediated MDR in the MDR human leukemia cell line k562/A02. It was found that si-MDR1 significantly inhibited MDR1 expression at both mRNA and protein levels.

Transient pancytopenia preceding T lineage acute lymphoblastic leukemia.

Transient pancytopenia preceding acute lymphoblastic leukemia (pre-ALL) is a rare occurrence usually affecting children with subsequent development of B lineage ALL. We report a case of pre-ALL characterized by a T cell immunophenotype and abnormal karyotype t (11; 14) (q10; q10). The patient achieved a transient complete remission after initial therapy, but relapsed within a few months and died of leukemic encephalopathy.

HI44a, an anti-CD44 monoclonal antibody, induces differentiation and apoptosis of human acute myeloid leukemia cells.

CD44 is a cell surface antigen that expresses on leukemia blasts from most acute myeloid leukemia (AML) patients. It has been reported that ligation of CD44 with some specific anti-CD44 monoclonal antibodies can reverse the differentiation blockage of leukemia cell lines. In this study, the differentiation and apoptosis-inducing effects of HI44a, another anti-CD44 monoclonal antibody (IgG2a), were investigated on leukemia cells obtained from 31 patients with AML-M2, AML-M3, AML-M4 or AML-M5.

No association of the plasminogen activator inhibitor-1 promoter 4G/5G polymorphism with inhibitor level during basal transcription in vitro.

Plasminogen activator inhibitor type 1 (PAI-1) has been shown to be an independent risk factor for coronary artery disease, myocardial infarction, and cerebrovascular events. Previous studies on variations in plasma PAI-1 levels and associations between PAI-1 levels and PAI-1 genotypes have suggested that PAI-1 expression maybe regulated in a genotype-specific manner by insulin, hypertriglyceridemic very low-density lipoprotein, and lipoprotein. We investigated whether basal transcription of the PAI-1 gene also is regulated in a genotype-specific manner.

Enhancement of neovascularization with cord blood CD133+ cell-derived endothelial progenitor cell transplantation.

The endothelial progenitor cells (EPCs) are responsible for postnatal vasculogenesis in physiological and pathological neovascularization and have been used for attenuating ischemic diseases. However, EPCs from umbilical cord blood (CB) were not well understood and the homing mechanisms of EPCs remain unclear. To determine the potential application of CB-derived EPCs, we established a culture system to induce the differentiation of CB cells into EPCs.

Intraspinal transplantation of CD34+ human umbilical cord blood cells after spinal cord hemisection injury improves functional recovery in adult rats.

The present study was designed to compare the functional outcome of the intraspinal transplantation of CD34+ human umbilical cord blood (CB) cells with that of human bone marrow stromal (BMS) cells in adult rats with spinal cord injury. Sixty adult Wistar rats were subjected to left spinal cord hemisection, and then divided into three groups randomly. The control group received an injection of PBS without cells, while the two other groups of rats received a transplantation of 5 x 10(5) CD34+ CB or BMS cells, respectively.

Platelet factor 4 enhances the adhesion of normal and leukemic hematopoietic stem/progenitor cells to endothelial cells.

Platelet factor 4 (PF4) is a growth regulator of hematopoietic stem/progenitor cells (HSPCs), but its role in modulating the adhesive property of normal and leukemic cells remains unclear. We used CD34(+) cord blood cells, KG1a cell line, human umbilical vein endothelial cells (HUVECs) and a transformed HUVECs ECV-304 cells to study the effect of PF4 on cell adhesion. When CD34(+) cord blood cells were cultured either in fibronectin-coated (FN) culture plate or over the layer of HUVECs for 2h, a concentration-dependent increase of the number of adhered cells was observed in the culture containing PF4.

Serum leptin levels in patients with idiopathic thrombocytopenic purpura.

Objectives: The purpose of this study was to evaluate serum leptin levels in idiopathic thrombocytopenic purpura (ITP), in order to determine the influence of leptin on the pathogenesis of ITP.

Subjects And Methods: Forty-six untreated patients with chronic ITP were compared with 40 healthy people of similar age, sex and body mass index (BMI). Serum leptin levels (ng/mL) were measured by enzyme-linked immunosorbent assay (ELISA).

Hemangiopoietin inhibits apoptosis of MO7e leukemia cells through phosphatidylinositol 3-kinase-AKT pathway.

Hemangiopoietin (HAPO) is a growth factor that significantly stimulates proliferation and survival of the primitive cells of hematopoietic and endothelial lineages. To determine the mechanism of action of HAPO, the anti-apoptotic activity and signal transduction pathway of HAPO were investigated using a factor-dependent leukemia cell line, the MO7e cells. Recombinant human HAPO (rhHAPO) was produced in Escherichia coli and purified by a series of column chromatography with a purity of more than 95%.

Short-term ex vivo expansion sustains the homing-related properties of umbilical cord blood hematopoietic stem and progenitor cells.

Background And Objectives: The homing of stem cells to the bone marrow microenvironment following transplantation is a specific movement eventually leading to the stem cells lodging in specialized niches of hematopoiesis. The present study was designed to develop an ex vivo expansion system capable of preserving the homing potential of hematopoietic stem/progenitor cells (HSPC).

Design And Methods: Umbilical cord blood (UCB) CD34+ cells were expanded in QBSF-60 serum-free medium with a simple early-acting combination of cytokines and were re-selected from the expanded products at different time points.

Autologous transplantation of peripheral blood stem cells as an effective therapeutic approach for severe arteriosclerosis obliterans of lower extremities.

Treatment of severe arteriosclerosis obliterans of lower extremities (ASOLE) remains a clinical challenge. To develop a more effective approach, we evaluated the clinical efficacy of autologous transplantation of mobilized peripheral blood stem cells (PBSCs) in 5 patients with ASOLE. The patients received recombinant human granulocyte colony-stimulating factor (rhG-CSF, 600 micro g/day) for 5 consecutive days.

Hemangiopoietin, a novel human growth factor for the primitive cells of both hematopoietic and endothelial cell lineages.

The cells of hematopoietic and vascular endothelial cell lineages are believed to share a common precursor, termed hemangioblast. However, the existence of a growth factor acting relatively specifically on hemangioblasts remains unclear. Here we report the identification of hemangiopoietin (HAPO), a novel growth factor acting on both hematopoietic and endothelial cell lineages.

Inhibition of K562 leukemia angiogenesis and growth by expression of antisense vascular endothelial growth factor (VEGF) sequence.

Vascular endothelial growth factor (VEGF), a major angiogenic factor, plays a key role in the growth of solid tumor. Recently, expression of VEGF and its receptors has been found on leukemic cells as well as on endothelial cells. VEGF may fulfill a fundamental role in promoting tumor angiogenesis and proliferation by stimulating both endothelial cells and leukemic cells.

Suppression of tumor growth by viral vector-mediated gene transfer of N-terminal truncated platelet factor 4.

Platelet factor four (PF4), an inhibitor of endothelial cell proliferation in vitro, inhibits angiogenesis and tumor growth in vivo in experimental animals. The present study was designed to determine whether gene therapy-mediated expression of a form of PF4 lacking 16 amino acids of N-terminus from tumor cells could inhibit angiogenesis and tumor growth in vivo. Two replication-defective recombinant retroviral vectors were constructed.

Treatment of acute promyelocytic leukemia and other hematologic malignancies with arsenic trioxide: review of clinical and basic studies.

Acute promyelocytic leukemia (APL) is now the most potentially curable subtype of acute myeloid leukemia in adults because of the introduction of novel approaches in the management of this disease. All-trans-retinoic acid (ATRA)-based therapy is now the first-choice treatment of patients presenting with de novo APL, and clinical studies have shown that nearly all patients who receive ATRA therapy achieve complete remission. However, approximately 20% to 30% of APL patients eventually have relapses with resistance to further ATRA treatment.

Adenovirus-mediated gene therapy with an antiangiogenic fragment of thrombospondin-1 inhibits human leukemia xenograft growth in nude mice.

Recent investigations support the idea that angiogenesis is involved in the pathophysiology of leukemia. Within a given microenvironment, the angiogenic response is regulated by a delicate balance of angiogenesis inducers and inhibitors. Thrombospondin-1 (TSP-1) is a multifunctional extracellular glycoprotein showing angiostatic properties in multiple in vitro and in vivo assays.

HGF receptor up-regulation contributes to the angiogenic phenotype of human endothelial cells and promotes angiogenesis in vitro.

Hepatocyte growth factor (HGF) is a mesenchyme-derived pleiotropic growth factor and a powerful stimulator of angiogenesis, which acts on cells by binding to the c-met receptor. The exact role of the endogenous HGF/c-met system in one or more steps of the angiogenic process is not completely understood. To contribute to this question we used immunocytochemical analysis, Western blotting, and reverse transcription-polymerase chain reaction to study the expression of c-met in endothelial cells cultured in different growth conditions.