Growth factors increase retroviral transduction but decrease clonogenic potential of umbilical cord blood CD34+ cells.

Background And Objective: The feasibility of gene marking or gene therapy protocols making use of purified CD34+ cells greatly depends on the efficiency of their stable transduction. The great potential of umbilical cord blood as a source of CD34+ cells combined with the availability of advanced cell purification procedures prompted us to evaluate whether incubation with growth factors might influence the type of cells effectively transduced by retroviral vectors.

Design And Methods: Isolated, at least 95% pure, CD34+ cells were infected with the LXSN murine retrovirus carrying the neomycin-resistance gene.

von Willebrand factor: biological function and molecular defects.

The human von Willebrand factor (vWF) plays a pivotal role in the mechanisms of blood clotting and platelet thrombus formation; it also binds and stabilizes factor VIII procoagulant protein. The biological functions of vWF are dependent on distinct molecular domains responsible for the specificity and affinity for ligands. The multimeric structure of vWF provides an array of binding sites that allow multivalent interactions, thus supporting the formation of stable platelet aggregates at the site of vascular injury, particularly under flow conditions characterized by high shear stress.

Platelet antibody detection in pediatric immune thrombocytopenic purpura: evaluation of three screening methods.

Background And Objectives: Immune thrombocytopenic purpura (ITP) is a common hematologic disorder, two forms of which occur in children. The detection of circulating platelet antibodies is helpful in diagnosis.

Materials And Methods: We evaluated three different immunological methods for detecting platelet antibodies in the serum of children with ITP.

[Platelet hyperaggregation induced by an antiplatelet monoclonal antibody in a female patient with essential thrombocythemia of childhood].

Essential thrombocythemia (ET) is a chronic myeloproliferative disease, rarely observed in pediatric age, characterized by a persistently increased platelet count. Abnormalities of platelet function observed in ET patients may be, at least in part, responsible for the thrombohemorrhagic complications. The authors report about a pediatric patient affected by ET, showing an abnormal platelet response following stimulation by anti-platelet monoclonal antibody.