BACKGROUND: Reperfusion causes injury to the coronary artery endothelium primarily by neutrophil-mediated mechanisms. However, factors other than neutrophils may govern the extent of @entity296 . This study tests the hypothesis that gradual initiation of reflow will reduce reperfusion injury and preserve postischemic endothelial function. METHODS: In 16 anesthetized @entity235 , the left anterior descending artery was ligated for 60 minutes. In one group, reperfusion was initiated abruptly (abrupt, n = 8), whereas in the gradual reperfusion group (ramp, n = 8), flow was slowly initiated during the first 30 minutes of reperfusion. After reperfusion, coronary artery segments were isolated to assess postischemic endothelial function. RESULTS: Infarct size (area of @entity39 /area at risk) was significantly reduced in the ramp group (28.2% +/- 2.0%) compared with abrupt (41.6% +/- 1.4%). Neutrophil accumulation ( @entity20402 ) in the area at risk was significantly greater in the ramp group compared with abrupt (8.0 +/- 1.3 versus 3.5 +/- 0.8 U/g tissue). In isolated postischemic left anterior descending arterial rings, the concentration of @entity934 that elicited a response 50% of the maximum possible response was significantly greater in abrupt (-6.88 +/- 0.04 log [mol/L]) than ramp (-7.62 +/- 0.04 log [mol/L]) and control (-7.68 +/- 0.003 log [mol/L]), suggesting @entity409 . The concentration of @entity3365 that elicited a response 50% of the maximum possible response was similarly greater in abrupt (-7.24 +/- 0.03 log [mol/L]) versus ramp (-7.62 +/- 0.03 log [mol/L]) and control (-7.8 +/- 0.04 log [mol/L]). Smooth @entity121 (response to @entity11495 ) also occurred in the abrupt rings. CONCLUSIONS: Gradual reperfusion of an ischemic area reduces @entity1188 size and preserves endothelial function but paradoxically increases neutrophil accumulation within the area at risk.

Gradual reperfusion reduces XXXX size and endothelial injury but augments neutrophil accumulation.

@entity296 :: ('MESH:D009202', 'Disease') :: ['myocardial necrosis'] @entity20402 :: ('609986(Tax:9615)', 'Gene') :: ['myeloperoxidase'] @entity39 :: ('MESH:D009336', 'Disease') :: ['necrosis'] @entity235 :: ('9615', 'Species') :: ['dogs'] @entity409 :: ('MESH:D008107', 'Disease') :: ['endothelial dysfunction'] @entity1188 :: ('MESH:D007238', 'Disease') :: ['infarct'] @entity11495 :: ('MESH:D012977', 'Chemical') :: ['sodium nitrite'] @entity3365 :: ('MESH:D000001', 'Chemical') :: ['A23187'] @entity121 :: ('MESH:D009135', 'Disease') :: ['muscle dysfunction'] @entity934 :: ('MESH:D000109', 'Chemical') :: ['acetylcholine']
@entity1188 :: (MESH:D007238,Disease) :: ['infarct']
