Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cardiopulmonary bypass is a planned support technique that results in a period of myocardial ischemia and reperfusion. In addition, it is associated with an inflammatory response likely involving endothelial cell activation. In previous studies, we showed that E-selectin and intercellular adhesion molecule-1 (ICAM-1) messenger ribonucleic acid (mRNA) are increased in human myocardium after cardiopulmonary bypass. We have now examined the expression of P-selectin mRNA by ribonuclease protection in paired atrial biopsy specimens from 12 patients before and after cardiopulmonary bypass. By means of immunocytochemistry, we have also examined the endothelial cell surface expression of P-selectin protein, as well as that of E-selectin and ICAM-1 in three additional patients. Patient ages ranged from 1 day to 8.5 years (median 12 months), and cardiopulmonary bypass times ranged from 46 to 196 minutes (median 144 minutes). By ribonuclease protection, there was marked variability in the expression of P-selectin in biopsy specimens before bypass. However, when compared with prebypass levels, P-selectin mRNA decreased modestly in 10 of 12 patients after bypass (median decrease 1.5-fold, p = 0.016). As seen with immunocytochemistry, P-selectin protein was distributed diffusely through the vascular bed on large vessels and small vessels before bypass but was virtually absent on capillaries in specimens taken after bypass. E-selectin, which was absent in prebypass biopsy specimens, was induced in one of the three specimens after bypass, but no change in ICAM-1 protein expression above baseline was noted. We also find that cultured human endothelial cells treated with tumor necrosis factor-alpha in doses which induce ICAM-1 mRNA simultaneously decrease their expression of P-selectin mRNA as compared with untreated cells. These observations suggest that endothelial P-selectin is transcriptionally downregulated after cardiopulmonary bypass at times when E-selectin and ICAM-1 are induced. Furthermore, we find that E-selectin and ICAM-1 are expressed at times and at sites where P-selectin is absent. Although it is possible that P-selectin may have been induced and lost at early times before reperfusion, these data suggest that endothelial P-selectin plays a limited role in the inflammatory response that ensues after cardiopulmonary bypass.
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PMID:P-selectin expression in myocardium of children undergoing cardiopulmonary bypass. 747 58

Activated endothelial cells up-regulate the expression of several molecules on their plasma membranes, including intercellular adhesion molecule-1 (ICAM-1). The role of heparin in regulating endothelial cell gene expression is unclear. We thus have investigated the ability of heparin to regulate ICAM- gene expression by using flow cytometry and the ribonuclease protection assay with human umbilical vein and aortic endothelial cells cultured in growth medium supplemented with 90 [microg/ml heparin (heparin-sufficient, HS) or in growth medium without added heparin (heparin-deficient, HD). We found that HD medium increased plasma membrane protein and mRNA for ICAM-1 but not for HLA-DR, even though both ICAM-1 and HLA-DR protein and mRNA were inducible by gamma interferon (IFN-gamma). In addition, phorbol ester and IFN-gamma increased the expression of plasma membrane ICAM-1 or ICAM-1 and HLA-DR, respectively, more in HD medium than in HS medium. We found that the HD-mediated increase of ICAM- mRNA was reversible by the addition of heparin, and that the half-life of ICAM-1 mRNA was the same in both HS- and HD-treated cells. Also, heparin was found to suppress increases in ICAM-1 mRNA at a concentration as low as 5 microg/ml. These findings indicate that heparin deficiency induces endothelial activation characterized by increased ICAM-1, and that such induction is not dependent on cytokines or endotoxin. The modulation of ICAM-1 expression by heparin appears to occur at the transcriptional level. Thus, heparin may have a role in regulating endothelial function by affecting the expression of ICAM-1, thereby impacting upon the trans-endothelial trafficking of leukocytes.
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PMID:Heparin regulates ICAM-1 expression in human endothelial cells: an example of non-cytokine-mediated endothelial activation. 975 31