• Applied Microscopy
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• 제22권1호
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• pp.42-54
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• 1992

To understand the structural changes of the myocardial myocytes and endothelial cells in ischemic and reperfused heart, and to elucidate their roles in those conditions, the authors observed cat and rat myocardium ultrastructurally and evaluated them with morphometric techniques. In cat, mild ischemia and moderate degree reperfusion injury was induced by ligation of the anterior interventricular branch of left coronary artery and reperfusion. In rat, severe ischemia and irreversible reperfusion iniury was made using in vitro Langendorff techniques. In normal cat myocytes, the volume densities of cytoplasm, myofibrils, mitochondria, sarcoplasmic reticulum and T tubules were $0.11{\pm}0.013,\;0.51{\pm}0.096,\;0.25{\pm}0.082,\;0.09{\pm}0.008,\;0.02{\pm}0.010$ (Mean${\pm}$S.D.) respectively, and the myofibril/mitochondria ratio was $2.33{\pm}1.379$. The numerical density and average volume of mitochondria were $0.76{\pm}0.210/{\mu}m^3$ and $0.33{\pm}0.057{\mu}m^3$ respectively. In normal cat endothelial cells, the volume densities of cytoplasm, cytoplasmic vesicles, tubular systems (including endoplasmic reticulum and Golgi apparatus) and mitochondria were $0.43{\pm}0.023,\;0.28{\pm}0.007,\;0.22{\pm}0.021,\;0.03{\pm}0.014$ respectively. The mean thickness of endothelial cells was $230{\pm}45.2{\mu}m$. The numerical density and average volume of cytoplasmic vesicles were $508{\pm}55.0/{\mu}m^3,\;578{\pm}104.8nm^3$ respectively. In cat myocytes which received mild ischemic injury, the volume densities of organelles were not changed significantly in ischemic and reperfusion states. In reperfusion group myocytes, the numerical density of mitochondria was decreased significantly and the average volume was increased significantly. In endothelial cells, the volume density of tubular system in ischemic group and the average volume of cytoplasmic vesicles in reperfusion group were increased significantly. In rat myocytes which received severe ischemic injury, the volume density and average volume of mitochondria were increased significantly, and the volume density of sarcoplasmic reticulum and numerical density of mitochondria were decreased significantly in both ischemic and reperfusion groups. In ischemic and reperfused endothelial cells, the volume density and numerical density of cytoplasmic vesicles, the volume density of cytoplasm were decreased significantly. The volume densities of tubular system were increased significantly in both ischemic and reperfused groups. The volume density of mitochondria in ischemic group and the average volume of cytoplasmic vesicles in reperfusion group showed significant increase. The authors, based on the above observations, conclude that the mitochondria of myocytes and the cytoplasmic vesicles of endothelia are the first group of targets in ischemic and reperfusion injury and in this respect, the degree of ischemic insult is not significant. The role of myocyte mitochondria in reperfusion injury may be insignificant, but endothelial cells may contribute actively to reperfusion injury.

• Biomolecules & Therapeutics
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• 제13권3호
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• pp.127-132
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• 2005

We investigated whether ischemic preconditioning (IPC) protects liver against cold ischemic injury using isolated perfused rat liver. Rat livers were preconditioned by 5 minutes of ischemia and 5 minutes of reperfusion and preserved for 30 hours at $4^{\circ}C$ in University of Wisconsin solution. Livers were then reperfused for 120 minutes. Oxygen uptake and bile flow in ischemic livers markedly decreased during reperfusion. These decreases were prevented by IPC. Portal pressure was elevated in cold ischemic and reperfused livers and this elevation was prevented by IPC. Lactate dehydrogenase and purine nucleoside phosphorylase activities markedly increased during reperfusion. These increases were prevented by IPC. The ratio of reduced glutathione to glutathione disulfide was lower in ischemic livers. This decrease was prevented by IPe. Our findings suggest that IPC protects the liver against the deleterious effect of cold ischemia/reperfusion, and this protection is associated with the reduced oxidative stress.

• Archives of Plastic Surgery
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• 제44권5호
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• pp.384-389
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• 2017

Background The aim of this study was to investigate the effects of remote ischemic conditioning on ischemia-reperfusion injury in rat muscle flaps histopathologically and biochemically. Methods Thirty albino rats were divided into 5 groups. No procedure was performed in the rats in group 1, and only blood samples were taken. A gracilis muscle flap was elevated in all the other groups. Microclamps were applied to the vascular pedicle for 4 hours in order to achieve tissue ischemia. In group 2, no additional procedure was performed. In groups 3, 4, and 5, the right hind limb was used and 3 cycles of ischemia-reperfusion for 5 minutes each (total, 30 minutes) was applied with a latex tourniquet (remote ischemic conditioning). In group 3, this procedure was performed before flap elevation (remote ischemic preconditoning). In group 4, the procedure was performed 4 hours after flap ischemia (remote ischemic postconditioning). In group 5, the procedure was performed after the flap was elevated, during the muscle flap ischemia episode (remote ischemic perconditioning). Results The histopathological damage score in all remote conditioning ischemia groups was lower than in the ischemic-reperfusion group. The lowest histopathological damage score was observed in group 5 (remote ischemic perconditioning). Conclusions The nitric oxide levels were higher in the blood samples obtained from the remote ischemic perconditioning group. This study showed the effectiveness of remote ischemic conditioning procedures and compared their usefulness for preventing ischemiareperfusion injury in muscle flaps.

• Advances in Traditional Medicine
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• 제9권1호
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• pp.67-73
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• 2009

Temporary clamping of the portal triad is a common strategy to minimize bleeding during liver transplantation. Increasing evidences suggests that oxygen derived free radicals and reintroduction of oxygen in ischemic tissue lead to ischemic and reperfusion injury (I/R) and lead to apoptosis and necrosis. Adult Wistar rat subjected to 60 min of partial liver ischemia followed by three hour reperfusion. Eighteen Wister rats were divided into sham-operated control group (I) (n = 6), ischemia and reperfusion group (II) (n = 6), folic acid treated group (1 mg/kg body weight/daily by oral route for 7 days before induced ischemia reperfusion maneuver) (III) (n = 6). Apoptotic and necrotic hepatocytes, mitochondrial antioxidant enzymes were measured. Liver injury was assessed by alanine transaminases (ALT), aspartate transaminases (AST), liver histopathology and electron microscopy. An ischemic and reperfusion hepatocellular injury was indicated by increased serum-ALT, AST, histopathology and electron microscopy studies. Apoptotic and necrotic cells were increased which was revealed by flow cytometry in I/R group. Pre- treatment with folic acid significantly decreased serum -ALT, AST levels, apoptotic and necrotic cells after 1 h ischemia followed by 3 h of reperfusion. Histopathology and TEM studies showed markedly diminished hepatocellular injury in folic acid pretreated rats during the hepatic I/R, which reached a level comparable to saline-treated rat of sham operated group. On the basis of our findings it may be concluded that folic acid afforded significant protection from necrosis and apoptosis in I/R injury.

• The Korean Journal of Physiology and Pharmacology
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• 제11권2호
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• pp.45-55
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• 2007

We elucidated the effects of various components of ischemic medium on the outcome of simulated ischemia-reperfusion injury. Hypoxia for up to 12 hours induced neither apoptotic bodies nor LDH release. However, reoxygenation after 6 or 12 hours of hypoxia resulted in a marked LDH release along with morphological changes compatible with oncotic cell death. H9c2 cells were then subjected to 6 hours of simulated ischemia by exposing them to modified hypoxic glucose-free Krebs-Henseleit buffer. Lowered pH (pH 6.4) of simulated-ischemic buffer resulted in the generation of apoptotic bodies during ischemia, with no concomitant LDH release. The degree of reperfusion-induced LDH release was not affected by the pH of ischemic buffer. Removal of sodium bicarbonate from the simulated ischemic buffer markedly increased cellular damages during both the simulated ischemia and reperfusion. Addition of lactate to the simulated ischemic buffer increased apoptotic cell death during the simulated ischemia. Most importantly, concomitant acidosis and high lactate concentration in ischemic buffer augmented the reperfusion-induced oncotic cell death. These results confirmed the influences of acidosis, bicarbonate deprivation and lactate on the progression and outcome of the simulated ischemia-reperfusion, and also demonstrated that concomitant acidosis and high lactate concentration in simulated ischemic buffer contribute to the development of reperfusion injury.

• Journal of Chest Surgery
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• 제21권5호
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• pp.803-815
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• 1988

The present experiments were performed to confirm the hypothesis that xanthine oxidase[XOD], as a source and mechanism of oxygen radical production, plays an important role in the genesis of the reperfusion injury of ischemic myocardium. The experimental ischemic-reperfusion injury was induced in isolated, Langendorff preparations of rat hearts by 60 min. Of global ischemia with aortic clamping followed by 20 min. of reperfusion with oxygenated Krebs-Henseleit solution[pH 7.4, 37*C]. The results were as follows: 1. The releases of creatine phosphokinase and a lipid peroxidation product, malondialdehyde[MDA] into the coronary effluent were abruptly increased upon reperfusion of ischemic hearts. The increases of the enzyme and MDA were suppressed significantly in the hearts removed from rats pretreated with allopurinol, a specific XOD inhibitor[20mg/kg, oral, 24 hrs and 2 hrs before study]. This effect of allopurinol was comparable to that of oxygen radical scavengers, superoxide dismutase[5, 000U] and catalase[12, 500 U]. 2. The increased SOD-inhibitable reduction of ferricytochrome C, which was infused to the hearts starting with reperfusion, was significantly suppressed in allopurinol pretreated hearts. 3. Activities of myocardial XOD were compared in the normal control hearts and the ischemic ones. Total enzyme activities were not different in both hearts. However, comparing with the control, the ischemic ones showed higher activity in 0-form and lower activities in D-form and D/O-form. 4. In the ischemic hearts, phenylmethylsulfonyl fluoride, a serine protease inhibitor, prevented significantly the increase of 0-form and the decreases of D and D/O-form, while thiol reagents did not affect the changes of the enzyme. 5. The increase of 0-form and the decreases of D and D/0-form were not significant in both calcium-free perfused and pimozide, a calmodulin inhibitor, treated ischemic hearts. 6. The SOD-inhibitable reduction of ferricytochrome C were suppressed by PMSF and pimozide treatment as well as by calcium-free perfusion. It is suggested from these results that in the ischemic rat myocardium, xanthine oxidase is converted to oxygen radical producing 0-form by calcium, calmodulin-dependent proteolysis and plays a contributing role in the genesis of ischemic-reperfusion injury by producing oxygen free radicals.

• 대한약리학회지
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• 제32권2호
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• pp.201-209
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• 1996

Restoration of the blood flow after a period of ischemia is accompanied by generation of toxic oxygen radicals. This phenomenon may account for the occurrence of reperfusion-mediated tissue injury in ischemic hearts. In in vitro studies, although oxygen radicals can be generated from a variety of sources, including xanthine oxidase system, activated leucocytes, mitochondria and others, the most important source and mechanism of oxygen radical production in the post-ischemic reperfused hearts is unclear. In the present study, we tested the hypothesis that the respiratory chain of mitochondria might be an important source of oxygen radicals which are responsible for the development of the reperfusion injury of ischemic hearts. Langendorff-perfused, isolated rat hearts were subjected to 30 min of global ischemia at $37^{\circ}C$, followed by reperfusion. Amytal, a reversible inhibitor of mitochondrial respiration, was employed to assess the mitochondrial contributions to the development of the reperfusion injury. Intact mitochonria were isolated from the control and the post-ischemic reperfused hearts. Mitochondrial oxygen radical generation was measured by chemiluminescence method and the oxidative tissue damage was estimated by measuring a lipid peroxidation product, malondialdehyde(MDA). To evaluate the extent of the reperfusion injury, post-ischemic functional recovery and lactate dehydrogenase(LDH) release were assessed and compared in Amytal-treated and -untreated hearts. Upon reperfusion of the ischemic hearts, MDA release into the coronary effluent was markedly increased. MDA content of mitochondria isolated from the post-ischemic reperfused hearts was increased to 152% of preischemic value, whereas minimal change was observed in extramitochondrial fraction. The generation of superoxide anion was increased about twice in mitochondria from the reperfused hearts than in those from the control hearts. Amytal inhibited the mitochondrial superoxide generation significantly and also suppressed MDA production in the reperfused hearts. Additionally, Amytal prevented the contractile dysfunction and the increased release of LDH observed in the reperfused hearts. In conclusion, these results indicate that the respiratory chain of mitochondria may be an important source of oxygen radical formation in post-ischemic reperfused hearts, and that oxygen radicals originating from the mitochondria may contribute to the development of myocardial reperfusion injury.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권4호
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• pp.287-294
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• 2006

Vascular thrombosis and ischemic necrosis still remain the most significant threats to the survival of free flaps. To date, neutrophils have been implicated in the pathogenesis of postischemic injury. Several studies have demonstrated that modulating the neutrophil response to ischemia-reperfusion injury can decrease the extent of the injury. In addition, some authors noticed that mast cell counts were also increased in flaps exposed to state of ischemia/reperfusion. So, we designed to evaluate the role of mast cells in ischemia/reperfusion by blocking histamine and to compare the effect of L-arginine, a nitric oxide precursor which is known to prevent neutrophil-mediated tissue injury. Epigastric island skin flaps were elevated in 30 rats and rendered ischemic. Thirty minutes prior to reperfusion, the rats were treated with intraperitoneal saline, diphenhydramine, cimetidine, and L-arginine. The necrosis rate of flap at 7 days, the number of neutrophils and mast cells at 20 hours were evaluated. In conclusion, histamine receptor blockers as well as L-arginine significantly decreased flap necrosis in a rat skin island ischemia-reperfusion flap model, but the protective effect was not significantly different in both agent groups.

• Advances in Traditional Medicine
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• 제9권4호
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• pp.292-302
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• 2009

Ischemia/reperfusion injury, which is commonly seen in the field of renal surgery or transplantation, is a major cause of acute renal failure. Previous studies showed that antioxidant treatments attenuated renal ischemia/reperfusion injury. The objective of this study was to examine the role of hesperidin in modulating reactive oxygen species induced inflammation and apoptosis after renal ischemia/reperfusion injury. Rats were subjected to right nephrectomy, 15 days later 45 min of renal ischemia and 24 h reperfusion with or without treatment with hesperidin. Renal function, inflammation and apoptosis were compared at 24 h after reperfusion injury. Hesperidin improved the renal dysfunction and reduced inflammation and apoptosis after ischemia/reperfusion injury. In conclusion, hesperidin shows potent anti-apoptotic and antiinflammatory properties due to antioxidant property. These findings may have major implications in the treatment of human ischemic acute renal failure.

• Journal of Korean Biological Nursing Science
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• 제23권3호
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• pp.217-226
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• 2021

Purpose: The aim of this study was to investigate the risk factors for brain reperfusion injury in ischemic stroke patients and to analyze the clinical outcomes. Methods: A retrospective study was conducted in 168 patients who underwent mechanical thrombectomy. The data were analyzed using descriptive statistics, t-test, Mann-Whitney U test, Chi-Square test, Fisher's exact test, and logistic regression with IBM SPSS/WIN 24.0. Results: Brain reperfusion injury occurred in 67 patients (39.9%) with a low favored outcome (𝛘²=6.01, p=.014). On multivariable analysis, blood urea nitrogen (Odds ratio [OR]=1.14, 95% Confidence interval [CI]=1.06-1.23), aphasia (OR=6.16, CI=1.62-23.40), anosognosia (OR=4.84, CI=1.13-20.79), presence of both aphasia and anosognosia (OR=7.33, CI=1.20-44.60), and time required to achieve targeted blood pressure (OR=1.00, CI=1.00-1.00) were identified as risk factors for brain reperfusion injury. A statistically significant difference was detected in clinical outcomes, including hemorrhagic transformation (𝛘²=6.32, p=.012), intensive care unit length of stay (Z=-2.08, p=.038), National Institute of Health Stroke scale score at discharge (Z=-3.14, p=.002), and modified Rankin Scale score at discharge (Z=-2.93, p=.003). Conclusion: This study identified the risk factors and presented the clinical outcomes of brain reperfusion injury. It is necessary to consider these risk factors for evaluating the patients and to establish nursing interventions and strategies.