Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to determine whether the administration of free radical antagonists, immediately before and during the early minutes of reperfusion, improves muscle survival 24 hr after a period of ischemia. Rabbit rectus femoris muscles were isolated, made ischemic for 3 1/2 hr and treated with either desferrioxamine (DFX), an Fe3+ chelator, superoxide dismutase and catalase (SOD & CAT), which quench superoxide and hydrogen peroxide, or allopurinol, an inhibitor of xanthine oxidase (XO). After 24 hr reperfusion, muscle viability (+/-s.e.m.), measured by the nitro blue tetrazolium (NBT) vital staining technique, was 41.6 +/- 11.3% for saline-treated ischemic controls, 30.6 +/- 7.6% for DFX-treated, 46.7 +/- 10.3% for SOD & CAT-treated, and 43.3 +/- 9.5% for allopurinol-treated muscles. None of the treated groups differed significantly from the ischemic control group. Tissue myeloperoxidase, ATP and reduced glutathione levels, and plasma lactate dehydrogenase (LDH) and aspartate transaminase (AST) levels were increased by ischemia and reperfusion in all groups, but the changes did not differ between the treatment groups. Levels of XO in the rabbit muscle were determined and found to be very low in both normal and postischemic muscle. As XO is the target enzyme of allopurinol, its absence provides a basis for the lack of effect of this agent. However, it is not clear why DFX and SOD & CAT had no protective effect.
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PMID:Influence of postischemic administration of oxyradical antagonists on ischemic injury to rabbit skeletal muscle. 939 70

Medium osmolarity sensitively regulates Kupffer cell functions like phagocytosis and prostaglandin (PG) and cytokine production. Betaine and taurine, recently identified as osmolytes in liver cells, interfere with these effects. Because Kupffer cell activation is an important pathogenic mechanism in ischemia-reoxygenation injury, the influence of osmolarity and osmolytes was investigated in a rat liver perfusion model of warm ischemia. Livers were perfused with different medium osmolarities for 60 to 90 minutes in the absence of oxygen, followed by another 90 minutes of reoxygenation. Lactate dehydrogenase (LDH) leakage into the effluent perfusate during the hypoxic and the reoxygenation period was eight- to 10-fold higher with a medium osmolarity of 385 mosmol/L than in normo-osmolarity, and further decreased with hypo-osmolar perfusion buffer. Betaine and taurine addition to the perfusate in near physiological concentrations decreased hypoxia-reoxygenation-induced LDH leakage, aspartate transaminase (AST) leakage, and perfusion pressure increase in hyperosmolar and normo-osmolar perfusions. Stimulation of PGD2, PGE2, thromboxane B2 (TXB2), and tumor necrosis factor alpha (TNF-alpha) release, as well as induction of carbon uptake by the liver during reoxygenation, were suppressed by betaine and taurine, pointing to an interference of these osmolytes with Kupffer cell function. In contrast, endothelial cell function as assessed by hyaluronic acid (HA) uptake was not influenced. It is concluded that warm ischemia-reoxygenation injury in rat liver is aggravated by hyperosmolarity and attenuated by hypo-osmolarity. The osmolytes betaine and taurine have a protective effect, presumably by inhibition of Kupffer cell activation.
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PMID:Cytoprotection by the osmolytes betaine and taurine in ischemia-reoxygenation injury in the perfused rat liver. 939 98

The aim of this study was to evaluate the tolerance of normothermic liver ischemia with different degrees of hepatic function in cirrhotic rats. Liver cirrhosis was induced by administering carbon tetrachloride (CCl4) in water solution to male Wistar rats. Hepatic function was graded using the plasma levels of antithrombin III, albumin, and bilirubin and the presence of ascites. Rats were distributed in four groups: noncirrhotic (control group), compensated cirrhosis (group A), decompensated cirrhosis (group B), and decompensated cirrhosis with ascites (group C). Groups A, B, and C were significantly different in all four parameters studied (P < .003). Subtotal liver ischemia was performed for periods of 0, 30, 45, 60, and 75 minutes. At the end of the procedure, the nonischemic lobes were resected. Postoperative evolution of alanine aminotransferase, aspartate aminotransferase, and bilirubin levels was also recorded. Survival rates after the same periods of ischemia were statistically different (P < .05): control group, 7 of 7 after 45 minutes (100%), 7 of 7 after 60 minutes (100%), and 4 of 9 after 75 minutes (44%); group A, 7 of 7 after 45 minutes (100%) and 1 of 7 after 60 minutes (14%); group B, 7 of 7 after 0 minutes (100%), 5 of 7 after 30 minutes (71%), and 1 of 7 after 45 minutes (14%); and group C, 0 of 5 after 0 minutes (0%) and 1 of 7 after 30 minutes (14%). No differences were found in the postoperative course of transaminases. However, bilirubin levels found 24 hours and 7 days after ischemia were significantly greater in cirrhotic rats, and this was directly related to the degree of hepatic insufficiency (P < .001). Histological examination of the livers exposed to CCl4 showed features of liver cirrhosis with ductal proliferation. The ischemia time tolerated by cirrhotic rat livers is shorter than the time tolerated by normal rats. Tolerance to hilar vascular occlusion depends on the degree of hepatic insufficiency. Rats with decompensated cirrhosis and ascites do not tolerate any surgical procedure.
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PMID:Vascular occlusion in hepatic resections in cirrhotic rat livers: an experimental study in rats. 940 63

Prevention of cellular damage after warm ischemia is of major importance in liver transplantation. In this study, we determined the extent to which lipid peroxides contribute to the pathogenesis of hepatic cell damage induced by transient warm ischemia with subsequent reperfusion. In addition, the function and immunohistochemical features of glutathione peroxidase, a potent physiological lipid peroxide scavenger of the liver, was assessed. Reperfusion following 15 or 30 minutes of warm ischemia resulted in a significant elevation in serum and liver lipid peroxidase (LPO) levels. In addition, necrosis of the hepatic periportal area accompanied with remarkable rises in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were observed. In contrast, 30 min of ischemia without reperfusion caused minimal hepatocellular damage. The adverse changes after ischemia/reperfusion were minimized by pretreatment with superoxide dismutase (SOD). These results indicate that increased lipid peroxidation by production of radicals after reperfusion caused the liver cell damage. After ischemia/reperfusion, liver glutathione peroxidase (GSH-PO) activity was significantly decreased and its location altered in the damaged liver. These findings suggest that GSH-PO contributes significantly to the protection against hepatic reperfusion injuries.
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PMID:Alterations in glutathione peroxidase activity following reperfusion injury to rat liver. 960 29

Lung injury often occurs after hepatoenteric ischemia, with xanthine oxidase (XO, an oxidant-generating enzyme), released from reperfusing liver and intestines, mediating a significant component of this injury. Since pentastarch administration decreases intestinal reperfusion injury, we determined whether resuscitation with PentaLyte (a pentastarch-containing solution) would decrease hepatoenteric reperfusion injury, xanthine oxidase release, and concomitant lung injury after aortic occlusion- reperfusion. Aortic occlusion was established in rabbits for 40 min, and was followed by 3 h of reperfusion, during which either PentaLyte or lactated Ringer's solution-based resuscitation was administered. Sham-operated animals served as controls. Hepatoenteric reperfusion injury, as manifested by release of the enzyme aspartate aminotransferase and decreased gastric intramucosal pH, was significantly (p < 0.0167) attenuated by PentaLyte administration after aortic occlusion-reperfusion, as compared with its occurrence in animals given lactated Ringer's solution. The release of XO after aortic occlusion-reperfusion was 4-fold smaller after PentaLyte administration than after resuscitation with lactated Ringer's solution (p < 0.05). Pulmonary injury, as defined by an increase in bronchoalveolar lavage fluid (BALF) protein content and lactate dehydrogenase (LDH) activity, was 4-fold less after PentaLyte administration following aortic occlusion-reperfusion than after administration of lactated Ringer's solution (p < 0.05). We conclude that remote pulmonary injury is significantly decreased by concomitant PentaLyte-mediated reduction of hepatoenteric reperfusion injury and XO release.
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PMID:PentaLyte decreases lung injury after aortic occlusion-reperfusion. 962 Sep 36

Recent studies suggest a crucial role played by mitochondria in the pathogenesis of ischemia-reperfusion injury. This study was conducted to clarify the role of trimetazidine, a cellular anti-ischemic agent, on mitochondria isolated from rat liver subjected to 120-min normothermic ischemia followed by 30-min reperfusion. Rats were divided into groups, pretreated with different doses of trimetazidine (5, 10 and 20 mg/kg/day) or saline and subjected to the ischemia-reperfusion process; another group served as the sham-operated controls. Alanine aminotransferase and aspartate aminotransferase activities and hepatocyte ATP content, bile flow and mitochondrial functions were assessed. Ischemia-reperfusion caused membrane leakage from hepatocytes and a decrease in ATP content and in bile flow. These effects were well correlated with alterations in mitochondrial function, namely, decrease in ATP synthesis, NAD(P)H level and mitochondrial membrane potential and generation of mitochondrial permeability transition. The pretreatment of rats with trimetazidine prevented these ischemia-reperfusion deleterious effects at both the cellular and mitochondrial level in a dose-dependent manner. It is concluded that trimetazidine at an optimal dosage of 10 mg/kg/day protects mitochondria against the deleterious effects of ischemia-reperfusion. This protective effect appears to be the key factor through which this drug exerts its cytoprotective activity.
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PMID:Trimetazidine counteracts the hepatic injury associated with ischemia-reperfusion by preserving mitochondrial function. 965 37

Liver transplantation (Ltx) has become a routine procedure for patients with end-stage liver disease. Despite ongoing progress on short- and long-term graft survival, primary dysfunction (PDF) remains a major problem. PDF is significantly associated with the duration of cold ischemia- and, possibly, with reperfusion-related injury. Nitric oxide (NO) has many physiological functions and plays an important role in modulating tissue injury. However, the mechanism of NO action in ischemia/reperfusion injury after Ltx is thus far unknown. In this study we investigated the role of inducable NO synthase (iNOS) in the liver after preservation with UW solution using the orthotopic Ltx model in the rat. Male Brown Norway rats were used for the Ltx procedure. After donor hepatectomy, livers were stored on ice-cold UW solution for 24 or 40 h and subsequently transplanted. A control group consisted of rats with Ltx after less than 1 h storage. Post-transplant blood samples were taken at 48 h to determine standard parameters for liver injury (aspartate transaminase, lactate dehydrogenase). Liver biopsies were obtained for detection of expression of iNOS (western blot) 24 and 48 h post-transplant. We observed that a preservation time of 24 h in UW solution presents no problem for graft survival after Ltx in rats with some brain function and in healthy animals. After 40 h preservation, liver damage is obvious and graft survival reduced, indicating the limits of cold storage may be within reach. With longer preservation times, more NOs was detected in liver tissue. This finding suggests that NO has a role in ischemia/reperfusion-related injury. Current intervention with NOS inhibitors will reveal whether NO has a negative or a positive effect on graft survival after Ltx.
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PMID:Extended preservation and effect of nitric oxide production in liver transplantation. 966 72

Interleukin-1 (IL-1) and tumor necrosis factor (TNF) are cytokines commonly associated with inflammatory conditions such as hepatic injury after ischemia-reperfusion. FR167653 has been characterized as a potent suppressant of IL-1beta and TNF-alpha production. In this study, we evaluated the effect of FR167653 in an extended liver resection with ischemia in a dog model. The right portal pedicle was clamped for 60 minutes, while the left portal branch was patent to avoid portal congestion. Following reperfusion, 75% of the liver (including the right central, quadrate, left central, left lateral, and papillary lobes) were resected. Animals were divided into two groups: a control group (n = 10), and a FR-treated group (n = 6) in which FR167653 was administered via the portal vein. Hepatic venous blood was collected to measure alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), purine nucleoside phosphorylase (PNP), and hyaluronic acid (HA) levels, and IL-1beta expression was also measured by reverse-transcriptase polymerase chain reaction (RT-PCR). ALT, AST, LDH, PNP, and HA levels after reperfusion were significantly lower (P < .05) in the FR-treated group than in the control group, and the FR-treated group showed inhibited IL-1beta expression. Liver tissue blood flow, measured by a laser Doppler flow meter, was kept higher in the FR-treated group than in the control group. Histologically, tissue damage was mild in the FR-treated group. The 2-day survival rate was statistically better (P < .05) in the FR-treated group than in the control group. We conclude that FR167653 provides a protective effect for liver parenchyma and sinusoidal endothelial cells in extended liver resection with ischemia.
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PMID:The effects of FR167653 in extended liver resection with ischemia in dogs. 969 12

The decreased tolerance of steatotic livers to warm ischemia complicates liver surgery. The efficacy of heat shock preconditioning in steatotic livers to lessen ischemia-reperfusion injury was studied in rats. Steatotic liver was produced in Lewis rats with a choline-deficient diet. Rats with steatotic livers were divided into a heat shock preconditioned group (group HS) and a control group (group C). All rats received 45 min of hepatic warm ischemia. Survival rates and changes in biochemical and histological parameters were compared in both groups. Heat shock protein 72 (HSP72) was produced only in group HS. The 7-day survival of the rats after warm ischemic intervention was significantly better in group HS (13/15) than in group C (5/15) (P < 0.01). The concentration of ATP in liver tissue (n = 10, P < 0.01) and serum levels of aspartate aminotransferase (n = 10, P < 0.05), alanine aminotransferase (n = 10, P < 0.01), and lactic dehydrogenase (n = 10, P < 0.01) at 40 min reperfusion were also significantly better in group HS than in group C. Histological examination at 40 min reperfusion showed severe sinusoidal congestion, hepatocyte necrosis, and increased positivity to 4-hydroxy-2-nonenal-modified proteins in group C livers; these signs were markedly suppressed in group HS livers. The data indicate that heat shock preconditioning provides the steatotic rat liver with significant tolerance to warm ischemia-reperfusion injury.
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PMID:Heat shock preconditioning ameliorates liver injury following normothermic ischemia-reperfusion in steatotic rat livers. 973 39

Intracellular-type electrolyte solutions were introduced into organ preservation to prevent K+ efflux and Na+ and Cl- influx into cells and cell swelling during cold ischemia. We studied cation accumulation in the interstitial space by microdialysis, during rat liver cold storage and after flush-out with high-K+ and low-K+ solutions. The effect of Na+ and K+ on graft function and survival was studied in an isolated perfused liver model and an orthotopic transplantation model after rat liver storage in iso-osmolar high-K+ and low-K+ solutions. After 24 hours of cold ischemia [Na+]o dropped from 136 +/- 2 mmol/L to 91.8 +/- 1.1 mmol/L, and [K+]o increased from 5.9 +/- 0.1 mmol/L to 12.2 +/- 1.6 mmol/L (P < .001 vs. control). [Na+]o and [K+]o after flush-out did not equilibrate with [Na+]sol and [K+]sol after 24 hours of cold storage. Rat livers preserved in low-K+ solutions produced significantly more bile during isolated reperfusion and released less alanine transaminase, aspartate transaminase, and lactate dehydrogenase into the reperfusion medium than high-K+ solutions. Rat liver survival after 14 hours of preservation was higher in low-K+ solutions (13 of 13) than in high-K+ solutions (7 of 13). Those studies indicate that during cold storage of rat livers, transmembraneous Na+-K+ sodium-potassium exchange might not follow the 3:2 stochiometry of a sole sodium-potassium exchange via Na+-K+ sodium-potassium adenosine triphosphatase (ATPase), and that low-K+ solutions might improve graft function and survival after rat liver preservation.
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PMID:Interstitial accumulation of Na+ and K+ during flush-out and cold storage of rat livers: implications for graft survival. 979 18


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