Flavonoids purified from parsley inhibit human blood platelet aggregation and adhesion to collagen under flow.

Introduction: Blood platelets are directly involved in both haemostatic and pathologic thrombotic processes, through their adhesion, secretion and aggregation. In this study, we investigated the effect of genins (aglycone flavonoids without sugar group) isolated from parsley (Petroselinum crispum) leaves in vitro on human platelet aggregation and adhesion to a collagen-coated surface under physiologic flow conditions.

Materials And Methods: The aggregation and adhesion studies were monitored after pre-incubation of platelets with genins.

The regulatory role of cell mechanics for migration of differentiating myeloid cells.

Migration of cells is important for tissue maintenance, immune response, and often altered in disease. While biochemical aspects, including cell adhesion, have been studied in detail, much less is known about the role of the mechanical properties of cells. Previous measurement methods rely on contact with artificial surfaces, which can convolute the results.

Ex vivo priming of endothelial progenitor cells with SDF-1 before transplantation could increase their proangiogenic potential.

Objective: As SDF-1 and its cognate receptor CXCR4 play a key role in the survival and mobilization of immature cells, we examined whether preconditioning of endothelial progenitor cells (EPCs) with SDF-1 could further promote their capacity to enhance angiogenesis.

Methods And Results: EPC exposure to 100 ng/mL SDF-1 for 30 min induced a proangiogenic phenotype, with cell migration and differentiation into vascular cords in Matrigel and increased their therapeutic potential in a nude mouse model of hindlimb ischemia. This pretreatment enhanced EPC adhesion to activated endothelium in physiological conditions of blood flow by stimulating integrin-mediated EPCs binding to endothelial cells.

Thrombospondin-1 (TSP-1) and TSP-1-derived heparin-binding peptides induce promyelocytic leukemia cell differentiation and apoptosis.

Thrombospondin-1 (TSP-1) is a multifunctional adhesive glycoprotein that is synthesized by several cell types and modulates cell growth and differentiation. In this study, we showed that the amount of TSP-1 secreted by two human leukemia cell lines, HL-60 and NB4, increased markedly during differentiation of these cells by all-trans retinoic acid (ATRA) (10(-7) M), reaching about 100 ng/10(6) cells after 3 days. Addition of purified TSP-1 alone (10(-9)-5 x 10(-8) M) to HL-60 or NB4 cell cultures dose-dependently inhibited cell growth and differentiation.

Spatial distribution patterns of interphase centromeres during retinoic acid-induced differentiation of promyelocytic leukemia cells.

Background: The pericentromeric heterochromatin is an important element for the regulation of gene silencing. Its spatial distribution during interphase appears to be cell-type specific. This study analyzes three-dimensional (3D) centromere distribution patterns during cellular differentiation along the neutrophil pathway.