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141.
Expression of tissue factor and factor VIIa/tissue factor inhibitor activity in endotoxin or phorbol ester stimulated U937 monocyte-like cells 总被引:5,自引:0,他引:5
Previously, unstimulated cells of the human monocytic tumor cell line U937 have been shown to possess a negligible cell-surface tissue factor (TF) activity, and to secrete a small amount of factor VIIa/tissue factor (VIIa/TF) inhibitor activity. On stimulation with endotoxin or with phorbol myristate acetate (PMA), TF of these cells is known to be increased approximately fourfold. In this report, we demonstrate that VIIa/TF inhibitor is also increased on stimulation of U937 cells with endotoxin (approximately equal to threefold) or with PMA (approximately equal to 20-fold). Notably, the secretion of the inhibitor persisted after the cell surface TF had started to decline. Further, when serum- free media from PMA stimulated cells was electrophoresed on a sodium dodecyl sulfate (SDS) gel, we eluted two inhibitor activity peaks corresponding to Mr approximately equal to 47,000 and Mr approximately equal to 36,000. The molecular weights of these peaks are similar to those obtained earlier from human plasma for this inhibitor(s). 相似文献
142.
The biological activity of the multifunctional cytokine interleukin-1 (IL-1) is mediated by its receptors. The aim of this study was to determine if an association exists between single nucleotide polymorphisms (SNPs) in the IL-1 type 1 and 2 receptor genes (IL1R1 and IL1R2) and the expression level of membrane-bound IL1Rs on subpopulations of mononuclear cells or serum levels of soluble IL-1 receptors. It was observed that healthy individuals with the genotype TT in SNP rs2234650:C>T had a lower percentage of intact CD14+ monocytes expressing IL1R1 on their surface. The SNP rs4141134:T>C in IL1R2 has also been associated with the percentage of intact CD3+ T cells expressing IL1R2. Furthermore, individuals carrying the CC allele of SNP rs4141134:T>C and the TT allele of SNP rs2071008:T>G in IL1R2 had a lower density of IL1R2s on the surface of CD14+ monocytes in lipopolysaccharide (LPS)-stimulated PBMC cultures. In summary, this study demonstrated that IL-1 receptor gene polymorphisms could be one of the factors influencing the expression of membrane-bound IL-1 receptors (IL1R) on immunocompetent cells. 相似文献
143.
To examine the appropriateness of the Food and Drug Administration's 10-year storage time for previously frozen red cells, 24-hour posttransfusion survival studies were performed, and the half-life of 3 units of autologous red cells that had been stored for 13.5, 14, and 17 years, respectively, was measured. The units had acceptable freeze-thaw-wash recovery (83.3-91.4%). When a 51Cr label was used for the previously frozen red cells and a simultaneous 52Cr label for freshly drawn autologous red cells was used as a comparison, it was seen that the previously frozen cells had normal 24-hour posttransfusion survival (75.1-88.4%) as well as normal half-life (23-33.7 days). These findings support further extension of the maximum allowable storage time for previously frozen red cells. 相似文献
144.
Fiona Heeman Denise Visser Maqsood Yaqub Sander Verfaillie Tessa Timmers Yolande AL Pijnenburg Wiesje M van der Flier Bart NM van Berckel Ronald Boellaard Adriaan A Lammertsma Sandeep SV Golla 《Journal of cerebral blood flow and metabolism》2023,43(3):369
Alzheimer’s disease is characterized by regional reductions in cerebral blood flow (CBF). Although the gold standard for measuring CBF is [15O]H2O PET, proxies of relative CBF, derived from the early distribution phase of amyloid and tau tracers, have gained attention. The present study assessed precision of [15O]H2O derived relative and absolute CBF, and compared precision of these measures with that of (relative) CBF proxies. Dynamic [15O]H2O, [18F]florbetapir and [18F]flortaucipir PET test-retest (TrT) datasets with eleven, nine and fourteen subjects, respectively, were included. Analyses were performed using an arterial input model and/or a simplified reference tissue model, depending on the data available. Relative CBF values (i.e. K1/K1′ and/or R1) were obtained using cerebellar cortex as reference tissue and TrT repeatability (i.e. precision) was calculated and compared between tracers, parameters and clinical groups. Relative CBF had significantly better TrT repeatability than absolute CBF derived from [15O]H2O (r = −0.53), while best TrT repeatability was observed for [18F]florbetapir and [18F]flortaucipir R1 (r = −0.23, r = −0.33). Furthermore, only R1 showed, better TrT repeatability for cognitively normal individuals. High precision of CBF proxies could be due to a compensatory effect of the extraction fraction, although changes in extraction fraction could also bias these proxies, but not the gold standard. 相似文献
145.