Spreading Shape and Area Regulate the Osteogenesis of Mesenchymal Stem Cells

BACKGROUND: Mesenchymal stem cells (MSCs) have strong self-renewal ability and multiple differentiation potential. Some studies confirmed that spreading shape and area of single MSCs influence cell differentiation, but few studies focused on the effect of the circularity of cell shape on the osteogenic differentiation of MSCs with a confined area during osteogenic process.METHODS: In the present study, MSCs were seeded on a micropatterned island with a spreading area lower than that of a freely spreading area. The patterns had circularities of 1.0 or 0.4, respectively, and areas of 314, 628, or 1256 µm² . After the cells were grown on a micropatterned surface for 1 or 3 days, cell apoptosis and F-actin were stained and analyzed. In addition, the expression of β-catenin and three osteogenic differentiation markers were immunofluorescently stained and analyzed, respectively.RESULTS: Of these MSCs, the ones with star-like shapes and large areas promoted the expression of osteogenic differentiation markers and the survival of cells. The expression of F-actin and its cytosolic distribution or orientation also correlated with the spreading shape and area. When actin polymerization was inhibited by cytochalasin D, the shape-regulated differentiation and apoptosis of MSCs with the confined spreading area were abolished.CONCLUSION: This study demonstrated that a spreading shape of low circularity and a larger spreading area are beneficial to the survival and osteogenic differentiation of individual MSCs, which may be regulated through the cytosolic expression and distribution of F-actin.

Evaluation of an automated morphological analysis system in white blood cell identificaton / 中华检验医学杂志

Objective To evaluate the clinical performance of an automated image analysis systems named CellaVision DM96 in classifying White Blood Cells.Methods A total of 2267 peripheral blood samples (male 1 235, female 1 034, average age 46) were obtained from outpatient and inpatient in Peking Union Medical College Hospital ( PUMCH ) . These samples were selected to evaluate the precision, sensitivity, specificity and the analytical error of the system.We first evaluated the coincidence rate of reclassification and manual microscopy.On the base of favourable coincidence rate, we then evaluated the correlations between the pre-classification and reclassification of segmented neutrophil, band neutrophil, lymphocyte, monocyte, eosinophile, basophile, blast cell, promyelocyte, myelocyte, metamyelocyte, plasma cell and reactive lymphocyte.Results The sensitivity and specificity of pre-classification of White Blood Cell were 46% -100% and 24%-92%, respectively.When studied on the cell level, the total coincidence rate of pre-classification was 88%.And the coincidence rates of pre-classification and reclassification of White Blood Cell were 6%-95% and 25%-100%, respectively.When assessed on the sample level, the coincidence rates of pre-classification and reclassification of leukocytes were 64%-98%and 84%-100%, respectively.The correlations of pre-classification and reclassification of leukocytes in order from high to low were: lymphocyte, segmented neutrophil, eosinophile, band neutrophil, monocyte, basophile, when r were 0.943 9, 0.915 2, 0.785 4, 0.775 6, 0.676 2 and 0.289 1, respectively.The correlations between reclassification and manual microscopy of White Blood Cell were higher than those between pre-classification and manual microscopy.Order from high to low was: eosinophile, segmented neutrophil, lymphocyte, monocyte, band neutrophil, basophile.And r were 0.972 1, 0.968 5, 0.957 0, 0.831 9, 0.800 6 and 0.648 7, respectively.The ability of this automated image analysis systems at pre-classification in distinguishing between band cell and segment cell, atypical lymphocyte and normal lymphocyte was not good. Conclusion The performance of reclassification was better than pre-classification.The reclassification can be substitute for the microscopy inspection, and be used in the Clinical practice.