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

We have recently demonstrated that endogenous H2O2 plays an important role in coronary autoregulation in vivo. However, the role of H2O2 during coronary ischemia-reperfusion (I/R) injury remains to be examined. In this study, we examined whether endogenous H2O2 also plays a protective role in coronary I/R injury in dogs in vivo. Canine subepicardial small coronary arteries (>or=100 microm) and arterioles (<100 microm) were continuously observed by an intravital microscope during coronary I/R (90/60 min) under cyclooxygenase blockade (n=50). Coronary vascular responses to endothelium-dependent vasodilators (ACh) were examined before and after I/R under the following seven conditions: control, nitric oxide (NO) synthase (NOS) inhibitor NG-monomethyl-L-arginine (L-NMMA), catalase (a decomposer of H2O2), 8-sulfophenyltheophylline (8-SPT, an adenosine receptor blocker), L-NMMA+catalase, L-NMMA+tetraethylammonium (TEA, an inhibitor of large-conductance Ca2+-sensitive potassium channels), and L-NMMA+catalase+8-SPT. Coronary I/R significantly impaired the coronary vasodilatation to ACh in both sized arteries (both P<0.01); L-NMMA reduced the small arterial vasodilatation (both P<0.01), whereas it increased (P<0.05) the ACh-induced coronary arteriolar vasodilatation associated with fluorescent H2O2 production after I/R. Catalase increased the small arterial vasodilatation (P<0.01) associated with fluorescent NO production and increased endothelial NOS expression, whereas it decreased the arteriolar response after I/R (P<0.01). L-NMMA+catalase, L-NMMA+TEA, or L-NMMA+catalase+8-SPT further decreased the coronary vasodilatation in both sized arteries (both, P<0.01). L-NMMA+catalase, L-NMMA+TEA, and L-NMMA+catalase+8-SPT significantly increased myocardial infarct area compared with the other four groups (control, L-NMMA, catalase, and 8-SPT; all, P<0.01). These results indicate that endogenous H2O2, in cooperation with NO, plays an important cardioprotective role in coronary I/R injury in vivo.
 ...
PMID:Cardioprotective role of endogenous hydrogen peroxide during ischemia-reperfusion injury in canine coronary microcirculation in vivo. 1664 91

Although hypothermia is one of the most powerful modulators that can reduce ischemic injury, the effects of hypothermia on the function of the cardiac autonomic nerves in vivo are not well understood. We examined the effects of hypothermia on the myocardial interstitial norepinephrine (NE) and ACh releases in response to acute myocardial ischemia and to efferent sympathetic or vagal nerve stimulation in anesthetized cats. We induced acute myocardial ischemia by coronary artery occlusion. Compared with normothermia (n = 8), hypothermia at 33 degrees C (n = 6) suppressed the ischemia-induced NE release [63 nM (SD 39) vs. 18 nM (SD 25), P < 0.01] and ACh release [11.6 nM (SD 7.6) vs. 2.4 nM (SD 1.3), P < 0.01] in the ischemic region. Under hypothermia, the coronary occlusion increased the ACh level from 0.67 nM (SD 0.44) to 6.0 nM (SD 6.0) (P < 0.05) and decreased the NE level from 0.63 nM (SD 0.19) to 0.40 nM (SD 0.25) (P < 0.05) in the nonischemic region. Hypothermia attenuated the nerve stimulation-induced NE release from 1.05 nM (SD 0.85) to 0.73 nM (SD 0.73) (P < 0.05, n = 6) and ACh release from 10.2 nM (SD 5.1) to 7.1 nM (SD 3.4) (P < 0.05, n = 5). In conclusion, hypothermia attenuated the ischemia-induced NE and ACh releases in the ischemic region. Moreover, hypothermia also attenuated the nerve stimulation-induced NE and ACh releases. The Bezold-Jarisch reflex evoked by the left anterior descending coronary artery occlusion, however, did not appear to be affected under hypothermia.
 ...
PMID:Hypothermia reduces ischemia- and stimulation-induced myocardial interstitial norepinephrine and acetylcholine releases. 1708 72

This study deals with the polyviewed expression of the altered contractility of the isolated ileum of the guinea-pig after ischemia/superfusion (I/S). Intestinal ischemia was produced by clamping the superior mesenteric artery for 40, 80 or 160 min. Ischemic and non-ischemic segments taken from the same guinea-pig were mounted for tension recording in organ baths and superfused (120 min) with an oxygenated Krebs-bicarbonate solution. Data were analyzed by means of the Polyview System software, which allows detecting simultaneously several events of one response. Histopathological changes in myenteric neurons were also examined. We found that ischemia in situ followed by superfusion in vitro (reoxygenation) severely reduces the spontaneous intestine contractile activity, and significantly decreases the maximal contractile response to ACh and to electrical field stimulation (EFS), the maximal rate of tension, and the sensitivity of the tissue to EFS. In addition, these ischemic intestines respond with a long-lasting contracture when electrical stimulation was started at supramaximal voltage. Functional alterations were time dependent. Neurons exhibited features of necrosis. These results provide clear evidence of detrimental effects of I/S on intestine contractile function. Digital analysis allows quantification of additional parameters important for evaluation of functional changes after I/S and of the degree of neuroprotection.
 ...
PMID:Polyviewed expression of the altered contractility of the guinea-pig ileum after ischemia in situ and superfusion in vitro. 1762 97

We report the case of a 32-year-old man who presented at the emergency department with severe chest pressure, left arm pain, and dizziness. These symptoms were described as intermittent, occurring after exercise and at rest. He had undergone several stress tests during the past 8 years, but no objective evidence of ischemia was produced. His history of hyperlipidemia and increasing frequency of symptoms prompted us to perform coronary angiography, which showed a single coronary artery with an ostium at the right sinus of Valsalva. The vessel had an initial, mixed common trunk that gave rise to both the right coronary artery proper and to the left coronary artery. The left main trunk followed a prepulmonic course. The anatomic features were eventually confirmed by computed tomographic angiography. The left main stem had a fixed 50% to 60% area narrowing, at baseline study. A treadmill stress myocardial perfusion study showed no evidence of ischemia. The patient was referred to a 2nd facility, where intravascular ultrasonography, at baseline, revealed 63% left main narrowing without evidence of atherosclerosis. Acetylcholine provocation demonstrated worsening of the stenosis to about 80%, with reproduction of angina and ST-segment depression, which indicated that medical management of spasm might provide symptomatic relief.
 ...
PMID:Single coronary artery with prepulmonic coursing left main coronary artery manifesting as prinzmetal's angina. 1817 28

Deficits in cholinergic function have been postulated to cause delirium and cognitive decline. This review examines current understanding of the cholinergic deficiency hypothesis in delirium by synthesizing evidence on potential pathophysiological pathways. Acetylcholine synthesis involves various precursors, enzymes, and receptors, and dysfunction in these components can lead to delirium. Insults to the brain, like ischemia and immunological stressors, can precipitously alter acetylcholine levels. Imbalances between cholinergic and other neurotransmitter pathways may result in delirium. Furthermore, genetic, enzymatic, and immunological overlaps exist between delirium and dementia related to the cholinergic pathway. Important areas for future research include identifying biomarkers, determining genetic contributions, and evaluating response to cholinergic drugs in delirium. Understanding how the cholinergic pathway relates to delirium may yield innovative approaches in the diagnosis, prevention, and treatment of this common, costly, and morbid condition.
 ...
PMID:Cholinergic deficiency hypothesis in delirium: a synthesis of current evidence. 1869 33

Sivelestat, a neutrophil elastase inhibitor, has been shown to attenuate pulmonary injury during ischemia and reperfusion by improving microcirculation and may be effective as a cardioprotective agent. Isolated rat hearts were Langendorff-perfused (constant pressure, 75 mmHg) with oxygenated Krebs-Henseleit bicarbonate buffer (KHB). The optimal sivelestat concentration at 19 micromol/l was revealed because left ventricular developed pressure (LVDP) recovery in 19 micromol/l sivelestat was highest among 0.19, 1.9, 19, 190, and 1900 micromol/l sivelestat (26+/-10, 33+/-7, 56+/-5*, 35+/-2, and 15+/-5%, respectively; *P<0.01). In order to examine the optimal administration timing, sivelestat was administered at pre- and post-ischemic phases. LVDP recovery and troponin-T were observed in pre-, post-ischemic sivelestat groups and control. After 60 min-reperfusion, LVDP recoveries were 42+/-10*, 45+/-19*, and 14+/-5%, respectively (*P<0.01 compared to control), and troponin-T values were 4+/-1, 2+/-1**, and 8+/-2, respectively (**P<0.05 compared to control). Acetylcholine-induced increase in coronary flow was also investigated to examine the sivelestat's cardioprotective mechanism. Ischemia-reperfusion (I/R) impaired the acetylcholine-induced increase in coronary flow (maximal changes: sham, 125+/-11%; I/R, 98+/-3; P<0.01) and this impairment was attenuated by sivelestat-perfusion at reperfusion (maximal change: 112+/-7%; P<0.05 vs. I/R). Sivelestat attenuates coronary endothelial ischemia-reperfusion injury and improves myocardial protection even when administered at the reperfusion period. This suggests a role for sivelestat in the preservation of coronary endothelial function enhancing myocardial protection.
 ...
PMID:Sivelestat reduces myocardial ischemia and reperfusion injury in rat hearts even when administered after onset of myocardial ischemia. 1927 53

This study investigated the feasibility and effects of organ bath to be used for detection of bronchial function of non-heart-beating donor (NHBD) lung after 1-h warm ischemia. Sixteen Swedish pigs were divided into two groups randomly: heart-beating donor (HBD) group and NHBD with 1-h warm ischemia (NHBD-1 h) group. The bronchial rings whose lengths and inner diameters were both 1.5 mm were obtained from isolated left lungs of all the pigs. Acetylcholine, arachidonic acid natrium and papaverine were used to test and compare the contractile and relaxant function of bronchial smooth muscles and epithelium-dependent relaxation (EpiDR) response between HBD and NHBD-1 h groups. The results showed that there was no significant difference in the values of bronchial precontraction between HBD and NHBD-1 h groups (5.18+/-0.07 vs 5.10+/-0.11 mN, P>0.05). No significant difference in the values of EpiDR responses between HBD and NHBD-1 h groups (1.26+/-0.05 vs 1.23+/-0.07 mN, P>0.05) was observed either. During the process of EpiDR induction, the rings had no spontaneous relaxation in two groups. In addition, papaverine solution completely relaxed the bronchial smooth muscles of all bronchial rings. It was concluded that after warm ischemia for 1 h, the contractile and relaxant abilities of bronchial smooth muscles, and the epithelium-dependent adjustment both kept intact. Organ bath model could be a liable and scientific way to evaluate the bronchial function of NHBD lung.
 ...
PMID:Detection of bronchial function of NHBD lung following one-h warm ischemia by organ bath model. 1951 18

The aim of the present study was to evaluate the effects of sildenafil on endothelium-dependent mesenteric artery vasorelaxation and nonadrenergic noncholinergic (NANC) ileal responses in an experimental rat intestinal ischemia-reperfusion (I/R) model. The superior mesenteric artery was occluded for 45 min of ischemia and then the clamp was removed for 60 min of reperfusion. Sildenafil (1 mg/kg, i.v.) or saline was administered prior to surgery in the I/R and sham-operated groups. Acetylcholine-induced relaxation of the mesenteric arteries, which were precontracted via submaximal phenylephrine, decreased markedly after I/R. Sildenafil pretreatment reversed the acetylcholine-induced relaxation. In the ileum, NANC responses were significantly attenuated following I/R, which were increased by sildenafil pretreatment. These results indicate that pretreatment with sildenafil prevented both endothelial dysfunction in the mesenteric artery and impairment of ileal NANC responses in a rat intestinal I/R model.
 ...
PMID:Endothelial dysfunction in the mesenteric artery and disturbed nonadrenergic noncholinergic relaxation of the ileum due to intestinal ischemia-reperfusion can be prevented by sildenafil. 1954 5

3',4'-dihydroxyflavonol (DiOHF) is a potent antioxidant that reduces infarct size following myocardial ischaemia-reperfusion. Since oxidative stress induced by myocardial ischaemia-reperfusion impairs endothelium-dependent vasodilatation, we investigated whether DiOHF preserved coronary endothelial function following ischemia-reperfusion. One week after surgery conscious, instrumented sheep were subjected to 1h of myocardial ischaemia followed by 7 days reperfusion. Immediately before reperfusion, sheep were injected with DiOHF (2mg/kg iv, n=4) or vehicle (dimethyl sulphoxide, n=4). Coronary vascular responses to the endothelium-dependent vasodilator acetylcholine (ACh, 0.05-10.0 microg/kg/min iv), sodium nitroprusside and phenylephrine were determined. After ischaemia-reperfusion, dP/dt(max) decreased from 1511+/-93 to 1094+/-53 mmHg/s, P<0.05) at 24h in the vehicle group, but by 7 days had returned towards baseline (1347+/-91 mmHg/s). DiOHF prevented the fall in dP/dt(max). Coronary conductance (CC) was increased (+34+/-4%) by 10 microg/kg ACh given before ischaemia, but this vasodilatation was significantly reduced after 24h and 7 days of reperfusion (+7+/-2%, +15+/-2%, respectively, both P<0.05). DiOHF partially preserved the coronary vasodilator response to ACh after 24h reperfusion (basal 37+/-7%, 24h 18+/-5%), and after 7 days reperfusion the response had recovered (31+/-7%). DiOHF significantly decreased infarct size, expressed as a percentage of area-at-risk, by 40% after 7 days reperfusion (vehicle 80+/-7%, DiOHF 46+/-11%, P<0.05). A single administration of DiOHF, during ischaemia and just prior to reperfusion, reduced infarct size, preserved ventricular contractility and caused a sustained protection against coronary endothelial dysfunction, with all these beneficial actions being preserved for 7 days reperfusion.
 ...
PMID:3',4'-Dihydroxyflavonol improves post-ischaemic coronary endothelial function following 7days reperfusion in sheep. 1982 72

In this study, two enantiomers of the drug, L-nebivolol and racemic nebivolol, were used to measure and compare their ability to prevent endothelial dysfunction, disturbed ileal contractility, and ileal injury induced by I/R. The superior mesenteric artery of male Sprague-Dawley rats was occluded for 45 min to induce ischemia, and then the clamp was removed for 60-min reperfusion. Drugs or saline were administered prior to the surgical procedure in the I/R and sham-operated groups. Vasodilation in the third branch of the mesenteric artery was evaluated with a myograph system. Isometric contractions of the ileal segments in response to acetylcholine or electrical field stimulation (EFS) (120 V, 2-ms pulse duration for 5 s, 1-20 Hz) were recorded on a polygraph. Additionally, the ileal segments were examined histopathologically. Acetylcholine-induced relaxation of the mesenteric artery, precontracted by submaximal phenylephrine, markedly decreased after I/R. L-nebivolol pretreatment reversed this relaxation, but racemic nebivolol did not. Contractions induced by both acetylcholine and EFS were significantly reduced after I/R. L-nebivolol, but not racemic nebivolol, prevented this reduction in the acetylcholine-induced contractions. I/R-induced reduction was prevented by L-nebivolol only in response to EFS of 20 Hz. Intestinal I/R caused severe ischemic injury in the rat ileum, which was prevented by L-nebivolol, but not racemic nebivolol. Control responses were not affected by L-nebivolol or racemic nebivolol. These results suggest that L-nebivolol had a protective effect against both endothelial dysfunction of the mesenteric artery and ileal injury induced by intestinal I/R; however, similar effects were not observed for racemic nebivolol.
 ...
PMID:Nebivolol has protective effect against endothelial and ileal dysfunction due to I/R. 1992 53


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>