Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ischemia-reperfusion injury in the rabbit ear is neutrophil (PMN)-mediated, and is significantly reduced by anti-adhesion agents directed against beta 2 integrins, P-selectin, or L-selectin. We further examined selectin-mediated adherence in this setting following the administration of soluble sialyl Lewis(x) (SLe(x)), the principal carbohydrate ligand for P-, L-, and E-selectin, at various times following reperfusion. Under constant ambient temperature conditions, the rabbit ear vascular supply was isolated and occluded with an atraumatic vascular clamp for 6 h, then allowed to reperfuse. Animals receiving i.v. SLe(x) (25 mg/kg bolus + 50 mg/kg infusion over 10 h) 1) at the time of reperfusion, 2) 1 h after reperfusion, 3) 4 h after reperfusion, or 4) 12 h after reperfusion were compared with control animals receiving either saline or sialyl lactosamine, an oligosaccharide structurally similar to SLe(x) but not involved in selectin recognition. Tissue injury was assessed by serial measurement of ear edema and by visual determination of ear necrosis over 7 days. Tissue edema and necrosis were significantly reduced in animals treated with SLe(x) immediately upon reperfusion or after a 1-h delay, but not in animals for whom SLe(x) administration was delayed by 4 or 12 h. Furthermore, SLe(x) administration alone had no effect on circulating leukocyte or PMN counts, or PMN expression of CD18 or L-selectin. We conclude that interruption of selectin-mediated adherence with soluble SLe(x) oligosaccharide attenuates reperfusion in the rabbit ear. The observation that SLe(x) is efficacious only if administered in the first hour after reperfusion suggests that the more immediately available P- and L-selectin participate in this PMN adhesion/injury process, whereas E-selectin, with its delayed endothelial expression, does not.
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PMID:Sialyl Lewis(x) oligosaccharide reduces ischemia-reperfusion injury in the rabbit ear. 756 Nov 10

P-selectin-mediated rolling is believed to be important in the recruitment of leukocytes to tissue after ischemia-reperfusion injury. The dorsal skin chamber was used to examine differences in the rolling and stable adhesion of circulating leukocytes in subcutaneous (SC) vessels of P-selectin-deficient and age-matched wild-type mice, both under basal conditions and after ischemia-reperfusion. Rolling in the postcapillary venules in SC tissue of P-selectin-deficient mice was significantly lower than that in wild-type mice under the basal conditions and post-ischemia-reperfusion (P < .05), but was not eliminated by the deletion of the P-selectin gene. No significant difference between P-selectin-deficient and wild-type mice in shear rate or leukocyte-endothelial adhesion was observed up to 24 hours after ischemia-reperfusion. These results show that P-selectin-mediated rolling is not a prerequisite for ischemia-reperfusion-induced leukocyte-endothelial adhesion in the skin.
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PMID:Rolling in P-selectin-deficient mice is reduced but not eliminated in the dorsal skin. 757 54

Leukocyte adherence to the endothelium after ischemia and reperfusion contributes to microvascular injury in most organs. The purpose of this study was to evaluate the leukocyte and endothelial cell adhesion molecules involved with ischemia-reperfusion (I/R)-induced pulmonary microvascular injury in the isolated rat lung. After 45 min of ischemia and 30 min of reperfusion, microvascular permeability was significantly increased and lung retention of leukocytes occurred. Pretreatment with monoclonal antibodies against the leukocyte adhesion molecule CD18 or the endothelial cell adhesion molecules intercellular adhesion molecule 1 and P-selectin significantly attenuated the I/R-induced permeability increase and lung sequestration of neutrophils, mononuclear leukocytes, and eosinophils. In contrast, immunoneutralization of the rat leukocyte adhesion molecule L-selectin neither protected against the I/R-induced permeability increase nor prevented lung sequestration of neutrophils and eosinophils. We conclude that leukocyte adherence in the pulmonary, microvasculature and subsequent permeability increase after I/R is dependent on the integrin CD18, its endothelial cell ligand intercellular adhesion molecule 1, and the endothelial cell rolling factor P-selectin but not the leukocyte rolling factor L-selectin.
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PMID:Adhesion molecules contribute to ischemia and reperfusion-induced injury in the isolated rat lung. 766 25

The cardioprotective effects of an mAb to P-selectin designated mAb PB1.3 was examined in a feline model of myocardial ischemia (MI) and reperfusion. PB1.3 (1 mg/kg), administered after 80 min of ischemia (i.e., 10 min before reperfusion), significantly attenuated myocardial necrosis compared to a non-blocking mAb (NBP1.6) for P-selectin (15 +/- 3 vs 35 +/- 3% of area at risk, P < 0.01). Moreover, endothelial release of endothelium derived relaxing factor, as assessed by relaxation to acetylcholine, was also significantly preserved in ischemic-reperfused coronary arteries isolated from cats treated with mAb PB1.3 compared to mAb NBP1.6 (67 +/- 6 vs 11 +/- 3, P < 0.01). This endothelial preservation was directly related to reduced endothelial adherence of PMNs in ischemic-reperfused coronary arteries. Immunohistochemical localization of P-selectin was significantly upregulated in the cytoplasm of endothelial cells that lined coronary arteries and veins after 90 min of ischemia and 20 min of reperfusion. The principal site of intracytoplasmic expression was in venous vessels. mAb PB1.3 significantly decreased (P < 0.01) adherence of unstimulated PMNs to thrombin and histamine stimulated endothelial cells in a concentration-dependent manner in vitro. These results demonstrate that PMN adherence to endothelium by P-selectin is an important early consequence of reperfusion injury, and a specific monoclonal antibody to P-selectin exerts significant endothelial preservation and cardioprotection in myocardial ischemia and reperfusion.
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PMID:In vivo neutralization of P-selectin protects feline heart and endothelium in myocardial ischemia and reperfusion injury. 851 48

Neutrophil adherence and/or aggregation has been implicated in ischemia reperfusion injuries. We examined the role of P-selectin in PMN-mediated injury after reperfusion of the rabbit ear. The ear was partially amputated, and then reattached leaving the central artery and vein intact. To induce ischemia the central artery was then occluded. Treatment was at reperfusion with either saline or one of two murine P-selectin mAbs, designated PB1.3 and PNB1.6 mAb PB1.3 cross-reacts with rabbit P-selectin and prevents histamine-induced leukocyte rolling, whereas PNB1.6 does not. Using a peroxidase-antiperoxidase system P-selectin was detected in the ischemic ear, but not in the nonischemic ear. Ear volume increased to 5.3 times baseline in the saline-treated animals (n = 8), 6.6 times baseline in the nonblocking mAb PNB1.6-treated animals (n = 2), and 3.7 times baseline in the blocking mAb PB1.3-treated animals (n = 8). Estimated tissue necrosis of the combined saline- and PNB1.6-treated animals was 46 vs. 2.7% for the mAb PB1.3-treated animals. We conclude that: (a) P-selectin is expressed in ischemia reperfusion; (b) P-selectin participates in PMN-endothelial cell interactions in ischemia reperfusion; and (c) inhibiting P-selectin adhesion significantly reduces reperfusion injury.
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PMID:Anti-P-selectin monoclonal antibody attenuates reperfusion injury to the rabbit ear. 769 90

Adhesion molecules are responsible for PMN-endothelial cell interactions involved in both PMN-mediated endothelial injury (e.g., after ischemia-reperfusion injury) and PMN-mediated host defense against bacterial infection. Inhibition of PMN-endothelial adherence with CD18 and P-selectin mAb has been shown to ameliorate the tissue injury resulting from ischemia and reperfusion under a variety of experimental conditions. However, interference with PMN function may result in an increased risk of bacterial infection. Previous investigations suggest that CD18 blockade can lead to increased infectious risk. Little is known of the infectious risks associated with selectin blockade. We report the effects of P-selectin blockade (using mAb PB1.3) on bacteria-induced PMN emigration into the peritoneum and subcutaneous (s.c.) tissue in rabbits. Leukocyte and PMN emigration into the peritoneum 4 h after inoculation with 10 ml of 10(9) CFU/ml Escherichia coli was significant in saline-treated animals, and not different in animals pretreated with mAb PB1.3. Similarly, the incidence and severity of abscess formation 7 days after s.c. inoculation with Staphylococcus aureus (10(7), 10(8), or 10(9) CFU) was not increased in rabbits pretreated with mAb PB1.3 compared to saline. PMN emigration to the s.c. S. aureus was also similar in both saline and mAb PB1.3-treated animals, as determined by light microscopy. We conclude that P-selectin blockade with mAb PB1.3: 1) does not interfere with acute, E. coli-induced PMN emigration into the peritoneum, 2) does not increase the incidence or severity of S. aureus abscess formation in s.c. tissue, and 3) interferes less with PMN antibacterial host defense mechanisms than inhibition of CD18-mediated PMN adherence.
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PMID:P-selectin blockade does not impair leukocyte host defense against bacterial peritonitis and soft tissue infection in rabbits. 769 61

Neutrophils have been implicated as the cause of vascular injury that can lead to organ dysfunction and organ failure following a variety of initiating events. In particular, neutrophils have been shown to be necessary for vascular or tissue damage to occur in ischemia-reperfusion injuries of some organs and in the generalized ischemia-reperfusion injury resulting from hemorrhagic shock. Adherence of neurotrophils to endothelium or homotypic aggregation of neutrophils is thought to be necessary for injuries of this type to occur and these cell-cell interactions are mediated by adhesion molecules on both endothelial cells and leukocytes. In our completed studies, monoclonal antibodies that recognize functional epitopes of the leukocyte CD11/CD18 provided protection from ischemia-reperfusion injury. In addition, preliminary studies investigating leukocyte L-selectin and endothelial P-selectin appear to provide protection from ischemia-reperfusion injury.
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PMID:Monoclonal antibodies to leukocyte and endothelial adhesion molecules attenuate ischemia-reperfusion injury. 825 Aug 13

Leukocytes can produce vascular injury following ischemia and reperfusion of tissue resulting in thrombosis, edema and necrosis. Leukocyte adhesion to endothelial cells allows formation of a protected microenvironment where inflammatory molecules can exceed anti-inflammatory molecules thus resulting in injury. Blocking adherence with monoclonal antibodies to adherence molecules can prevent reperfusion injury to a variety of organs. In particular, antibodies to CD18 and P-selectin have been shown to be effective in ameliorating injury.
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PMID:The role of adhesion molecules in reperfusion injury. 831 35

Elevated levels of shear stress that occur in stenotic arteries may induce platelet aggregation and initiate thrombosis. Shear-induced platelet aggregation (SIPA) was studied in groups of ischemic stroke patients and normal subjects using a viscometric-flow cytometric technique. Twenty-three patients who sustained an ischemic stroke that was not of cardiac origin were included in this study, and were classified either as atherosclerotic (n = 15) or as lacunar (n = 8) stroke patients. The results show that shear stresses at the levels which occur in arteries partially occluded by atherosclerosis or vascular spasm strongly activate and aggregate platelets, and this response is much more pronounced in non-lacunar stroke patients who had documented atherosclerotic disease of their cerebral vessels. SIPA is not affected by the time of blood drawing after the onset of stroke suggesting that these platelet abnormalities are not transient but chronic. Furthermore, the extent of platelet activation detected by an anti-P-selectin monoclonal antibody and the proportion of neutrophil-platelet aggregates circulating in vivo are significantly higher in the atherosclerotic stroke patients studied at least one month after the onset of stroke. The results indicate that the enhanced platelet responses observed in atherosclerotic stroke patients are not consequences of ischemia, and therefore both platelet activation and elevated SIPA may be considered as important risk factors for stroke. The methodology developed in this work may be useful for characterization of platelet reactivity, and may contribute to our understanding of thrombotic mechanisms.
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PMID:Shear-induced platelet aggregation in normal subjects and stroke patients. 860 18

Reperfusion of the infarcted canine myocardium after 1 hour of ischemia is associated with an acute inflammatory infiltrate at the border of the infarct. In this paper, we demonstrate that early margination and emigration of neutrophils originate in thin-walled (approximately 5 micrometers) venous cisterns that average 200 micrometers in length and vary from 10 to 70 micrometers in width and show strong constitutive expression of both ICAM-1 and P-selectin; this class of vessels (venous cisterns) appears to be a unique feature in heart. A monoclonal antibody (SG8H6) with specificity for canine neutrophils was developed that allowed much more sensitive immunohistochemical detection of neutrophils in tissue and allowed us to follow tissue infiltration with time. Samples from 1 hour of reperfusion revealed dense margination and substantial emigration of neutrophils associated with the venous cisterns and collecting venules. By 2 hours, there was intense local emigration to the extravascular space between cardiac myocytes. By 3 hours, the infiltrate extended deeper into the infarct, and there was a continuous border zone of neutrophil infiltration that overlapped a region where intact cardiac myocytes strongly expressed ICAM-1 mRNA and extended into the necrotic tissue. At later times, neutrophil migration into infarcted tissue continued to progress. Neutrophil transmigration into reperfused myocardium is more extensive than previously described, and its extravascular distribution during early reperfusion is primarily in the viable border zone of the myocardium where myocyte ICAM-1 mRNA is found. These data are compatible with the hypothesis that extravascular neutrophils may participate in reperfusion injury.
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PMID:Acute inflammatory reaction after myocardial ischemic injury and reperfusion. Development and use of a neutrophil-specific antibody. 866 81


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