Proceedings of The National Academy of Sciences, 1997
We have shown that coculture of bone marrow microvascular endothelial cells with hematopoietic pr... more We have shown that coculture of bone marrow microvascular endothelial cells with hematopoietic progenitor cells results in proliferation and differentiation of megakaryocytes. In these long-term cultures, bone marrow microvascular endothelial cell monolayers maintain their cellular integrity in the absence of exogenous endothelial growth factors. Because this interaction may involve paracrine secretion of cytokines, we evaluated megakaryocytic cells for secretion of vascular endothelial growth factor (VEGF). Megakaryocytes (CD41a ؉ ) were generated by ex vivo expansion of hematopoietic progenitor cells with kit-ligand and thrombopoietin for 10 days and further purified with immunomagnetic microbeads. Using reverse transcription-PCR, we showed that megakaryocytic cell lines (Dami, HEL) and purified megakaryocytes expressed mRNA of the three VEGF isoforms
Deep-vein thrombosis is a potentially life-threatening complication of total hip or knee replacem... more Deep-vein thrombosis is a potentially life-threatening complication of total hip or knee replacement. There are few data on the effectiveness and safety of warfarin as compared with low-molecular-weight heparin as prophylaxis against this problem. We therefore performed a randomized, double-blind trial in 1436 patients to evaluate the effectiveness and safety of low-molecular-weight heparin (given subcutaneously once daily) as compared with adjusted-dose warfarin to prevent venous thrombosis after hip or knee replacement. Treatment with the drugs was started postoperatively. The primary end point was deep-vein thrombosis as detected by contrast venography (performed a mean of 9.4 days after surgery in each group). Among the 1207 patients with interpretable venograms, 231 of 617 patients (37.4 percent) in the warfarin group and 185 of 590 patients (31.4 percent) in the low-molecular-weight-heparin group had deep-vein thrombosis (P = 0.03). The reduction in risk with low-molecular-weight heparin as compared with warfarin was 16 percent, and the absolute difference in the incidence of venous thrombosis was 6 percent in favor of low-molecular-weight heparin (95 percent confidence interval, 0.8 to 11.4 percent). The incidence of major bleeding was 1.2 percent (9 of 721 patients) in the warfarin group and 2.8 percent (20 of 715 patients) in the low-molecular-weight-heparin group (P = 0.04), and the absolute difference was 1.5 percent in favor of warfarin (95 percent confidence interval, 0.1 to 3.0 percent). Our data demonstrate that the small reduction in the incidence of venous thrombosis with low-molecular-weight heparin, as compared with warfarin, was offset by an increase in bleeding complications. Although the use of low-molecular-weight heparin is simpler, because it is administered subcutaneously without the need for monitoring, it may be more costly than warfarin. Warfarin is inexpensive, but the overall cost of its use is increased by the need to monitor the intensity of anticoagulation. At this time it is unclear which of these approaches is the most cost effective.
sets, the tacit constraints invoked by maximum likelihood also involve inequality restrictions on... more sets, the tacit constraints invoked by maximum likelihood also involve inequality restrictions on Slutsky terms. The empirical work presented in this study supports the contention that these implicit constraints play a major role in explaining the discrepancies in estimates found in the literature on men's labor supply.
Proceedings of The National Academy of Sciences, 1997
We have shown that coculture of bone marrow microvascular endothelial cells with hematopoietic pr... more We have shown that coculture of bone marrow microvascular endothelial cells with hematopoietic progenitor cells results in proliferation and differentiation of megakaryocytes. In these long-term cultures, bone marrow microvascular endothelial cell monolayers maintain their cellular integrity in the absence of exogenous endothelial growth factors. Because this interaction may involve paracrine secretion of cytokines, we evaluated megakaryocytic cells for secretion of vascular endothelial growth factor (VEGF). Megakaryocytes (CD41a ؉ ) were generated by ex vivo expansion of hematopoietic progenitor cells with kit-ligand and thrombopoietin for 10 days and further purified with immunomagnetic microbeads. Using reverse transcription-PCR, we showed that megakaryocytic cell lines (Dami, HEL) and purified megakaryocytes expressed mRNA of the three VEGF isoforms
Deep-vein thrombosis is a potentially life-threatening complication of total hip or knee replacem... more Deep-vein thrombosis is a potentially life-threatening complication of total hip or knee replacement. There are few data on the effectiveness and safety of warfarin as compared with low-molecular-weight heparin as prophylaxis against this problem. We therefore performed a randomized, double-blind trial in 1436 patients to evaluate the effectiveness and safety of low-molecular-weight heparin (given subcutaneously once daily) as compared with adjusted-dose warfarin to prevent venous thrombosis after hip or knee replacement. Treatment with the drugs was started postoperatively. The primary end point was deep-vein thrombosis as detected by contrast venography (performed a mean of 9.4 days after surgery in each group). Among the 1207 patients with interpretable venograms, 231 of 617 patients (37.4 percent) in the warfarin group and 185 of 590 patients (31.4 percent) in the low-molecular-weight-heparin group had deep-vein thrombosis (P = 0.03). The reduction in risk with low-molecular-weight heparin as compared with warfarin was 16 percent, and the absolute difference in the incidence of venous thrombosis was 6 percent in favor of low-molecular-weight heparin (95 percent confidence interval, 0.8 to 11.4 percent). The incidence of major bleeding was 1.2 percent (9 of 721 patients) in the warfarin group and 2.8 percent (20 of 715 patients) in the low-molecular-weight-heparin group (P = 0.04), and the absolute difference was 1.5 percent in favor of warfarin (95 percent confidence interval, 0.1 to 3.0 percent). Our data demonstrate that the small reduction in the incidence of venous thrombosis with low-molecular-weight heparin, as compared with warfarin, was offset by an increase in bleeding complications. Although the use of low-molecular-weight heparin is simpler, because it is administered subcutaneously without the need for monitoring, it may be more costly than warfarin. Warfarin is inexpensive, but the overall cost of its use is increased by the need to monitor the intensity of anticoagulation. At this time it is unclear which of these approaches is the most cost effective.
sets, the tacit constraints invoked by maximum likelihood also involve inequality restrictions on... more sets, the tacit constraints invoked by maximum likelihood also involve inequality restrictions on Slutsky terms. The empirical work presented in this study supports the contention that these implicit constraints play a major role in explaining the discrepancies in estimates found in the literature on men's labor supply.
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