Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.109 (AST)
 6,066 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protective effect of metipranolol on renal ischemia has recently been demonstrated in our laboratory. The aim of present work was to investigate the effect of this drug on a model of total hepatic ischemia. Inosine was chosen as a comparative agent. Metipranolol (1 mg.kg-1) or inosine (160 mg.kg-1) were given i.v. to rats 15 min prior to inducing of 30-min lasting hepatic ischemia. The animals were followed up for 90 min after the end of ischemia. Pretreatment with inosine almost removed the harmful effect of ischemia on bile flow. Pretreatment with metipranolol slightly minimized the post-ischemic bile flow fall, this effect having been statistically significant only at 30. min of postischemic period. Neither inosine, nor metipranolol administration influenced significantly the ALT or AST plasma activity 90 min after release of hepatic vessels occlusion.
 ...
PMID:The effect of metipranolol and inosine on total hepatic ischemia of rats in vivo. 790 75

Acute hepatocellular injury, whether due to viral hepatitis, hepatic ischemia, or drug hepatotoxicity, results in elevated levels of serum aminotransferases (AST and ALT). Serum lactate dehydrogenase (LD) is reported to be markedly elevated in ischemic hepatitis. Thus, comparisons of the degree of elevation of serum levels of LD, ALT, and AST may be helpful in the differential diagnosis of acute liver injury. To study this, we reviewed serum enzyme patterns early in the course of acute liver injury in patients with acute viral hepatitis A and B (n = 51), ischemic hepatitis (n = 20), and acetaminophen injury (n = 26). All patients had serum ALT and/or AST at least five times the upper limit of normal. For a given ALT and AST level, LD was higher in ischemic hepatitis and acetaminophen injury than in viral hepatitis. The mean ALT/LD ratio for acute viral hepatitis was 4.65, for ischemic hepatitis 0.87, and for acetaminophen injury 1.46. Mean ALT/LD ratio for viral hepatitis was significantly higher (p < 0.0001) than for the other two groups combined. An ALT/LD ratio of 1.5 differentiated acute viral hepatitis from ischemic hepatitis and acetaminophen injury with a sensitivity of 94% and a specificity of 84%.
 ...
PMID:Serum lactic dehydrogenase in the differential diagnosis of acute hepatocellular injury. 796 56

Glycine has been shown to decrease membrane injury in isolated cells due to hypoxia or cold ischemia. The mechanisms of action of glycine are not known, but glycine may be useful in organ preservation solutions or in treating recipients of liver transplantation. In this study the isolated, perfused rabbit liver was used to measure how glycine affected liver performance after 48-h preservation in University of Wisconsin (UW) solution without added glutathione. UW solution is less effective for 48-h liver preservation when glutathione is omitted. Rabbit livers stored for 48 h without glutathione show a large increase in enzyme release (LDH and AST) from the liver and a reduction in bile production. The addition of 15 mM glycine to UW solution, in place of glutathione, did not improve bile production or reduce enzyme release. However, infusion of 10 mM glycine into the reperfused liver lowered LDH release significantly (from 2383 +/- 562 units/100 g to 1426 +/- 286 units/100 g) during the initial reperfusion of the 48-h preserved liver. Hepatamine, a parenteral nutrition solution containing glycine, as well as other amino acids, was also effective in lowering LDH release from the preserved liver. Although glycine reduced LDH release, it did not decrease the amount of AST released from the liver, nor did it improve bile production. Thus, we conclude that glycine, either in UW solution or given to the liver upon reperfusion, has no significantly beneficial effect as tested in this model. Further testing of glycine, however, should be conducted in an orthotopic transplant model in the rat or dog.
 ...
PMID:Effect of glycine on isolated, perfused rabbit livers following 48-hour preservation in University of Wisconsin solution without glutathione. 806 Apr 69

The early outcome of 201 liver grafts transplanted consecutively between September 1988 and November 1991 was investigated retrospectively. Donors were categorized according to their hospitalization periods in an intensive care unit (ICU) prior to harvesting, their causes of death, and the variables generally believed to be critical in liver donation, such as arterial hypotension (n = 69; 34.3%), cardiopulmonary resuscitation (n = 20; 9.9%), elevated serum-aminotransferases (s-AT) (n = 11; 5.5%), or an age over 50 years (n = 16; 8.0%). Ninety-one donors (45.3%) spent less than 24 h in an ICU; 29 donors (14.4%) and 14 donors (7.0%) had hospitalization periods generally considered critical of 4-6 days and more than 6 days, respectively. The most common causes of death were subarachnoidal bleeding (n = 70; 34.8%), isolated head injuries (n = 68; 33.8%), and polytraumata (n = 33; 16.4%). The postischemic hepatocellular damage was evaluated comparing peak post-transplant s-AT, which did not differ significantly between groups; nor did donor and recipient ages or cold ischemia times. Fourteen grafts (7.0%) showed a reversible preservation injury presenting with post-transplant s-AT elevated above 2000 IU/l. Five cases (2.5%) of a primary non-functioning graft (PNF) underwent early retransplantation successfully. Serum-aminotransferases (AST: 4944 +/- 2280 IU/l; ATL: 3186 +/- 1918 IU/l) were significantly (P < 0.01) elevated as compared to primary functioning grafts (AST: 699 +/- 935 IU/l; ALT: 620 +/- 701 IU/l). The donor structure of both groups reflected the distribution of variables in the entire collective. No significant overrepresentations were observed.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Donor criteria in hepatic transplantation. 814 13

S-Adenosylmethionine (SAMe) and N-acetylcysteine (NAC), two agents with known benefit for reducing hepatic injury, were used to treat ischemic injury in a rat liver perfusion model. We compared cold ischemic injury with sequential periods of cold and warm ischemia that equate to episodes during the storage and implantation of liver grafts. The additional period of 20 min warm ischemia after 24 hr cold ischemia profoundly impaired initial (15 min) mean blood flow (1.8 +/- 0.1 vs. 2.7 +/- 0.4 ml/min/g liver for cold ischemia, P < 0.001) and bile flow (2.31 +/- 0.74 vs. 10.6 +/- 3.96 mg/hr/g liver for cold ischemia, P < 0.001) and increased the oxygen extraction ratio (OER) (0.53 +/- 0.03 vs. 0.29 +/- 0.08 for cold ischemia, P < 0.01) and acid release from glycolysis (0.18 +/- 0.02 vs. 0.11 +/- 0.02 mmol/g liver for cold ischemia, P < 0.05). Impairment of blood flow, bile flow, and OER was sustained throughout the 3-hr perfusion. In the same model, SAMe restored hepatic blood flow to control values when administered to the donor, included in the UW, and added as a bolus to the perfusate on reperfusion. SAMe also improved OER (P < 0.001 vs. sequential cold and warm ischemia) and initial bile flow (9.63 +/- 2.01 mg/hr/g liver, P < 0.01), returning values to control levels by 3 hr. SAMe reduced the initial release of glucose upon reperfusion (P < 0.01) and improved subsequent glucose uptake, but corresponding benefits on enzyme release from damaged hepatocytes (AST) or endothelial cells (purine nucleoside phosphorylase) were not observed. Equimolar concentrations of NAC induced transitory improvements in blood and bile flow but these were not sustained beyond 30 min of reperfusion.
 ...
PMID:Evidence that S-adenosylmethionine and N-acetylcysteine reduce injury from sequential cold and warm ischemia in the isolated perfused rat liver. 817 41

Reactive oxygen metabolites generated from xanthine oxidase play an important role in the pathogenesis of ischemia-induced tissue injury. In a hemorrhagic shock model of ischemia-reperfusion, the intracellular enzyme xanthine oxidase was released into the vasculature. This intravascular source of superoxide (O2.-) and hydrogen peroxide (H2O2) interacted reversibly with glycosaminoglycans of vascular endothelium and markedly concentrated xanthine oxidase at cell surfaces, enhancing its ability to produce extensive damage to remote tissues. Rats were made hypotensive by hemorrhage, maintained for 2h, and reinfused with shed blood. Blood samples were obtained prior to hemorrhage and 15, 30, 60, and 90 min after reperfusion for determination of xanthine oxidase (XO), lactate dehydrogenase (LDH), and alanine transaminase (AST). These enzymes were not significantly elevated in control animals. Reperfusion after hemorrhage-induced ischemia resulted in significantly elevated AST and LDH in both low heparin (100 U/h) and high heparin (1000 U/h) groups. Xanthine oxidase was detected in the circulation only after 90 min reperfusion in the low heparin group and was elevated during the entire reperfusion period in the high heparin group. Studies with cultured vascular endothelium showed significant heparin-reversible binding of XO to cellular glycosaminoglycans. These results suggest that XO can gain access to the circulation following ischemia, where it then binds to the vascular endothelial cells to produce site-specific oxidant injury to organs remote from the site of XO release.
 ...
PMID:Xanthine oxidase activity in the circulation of rats following hemorrhagic shock. 822 22

Lipid peroxidation may play a major role in the loss of liver graft viability after prolonged cold ischemia and reperfusion injury. The lazaroid compound U74006F is a potent inhibitor of lipid peroxidation, and this study was designed to evaluate the efficacy of this compound in preventing cold ischemia-reperfusion damage in three different models: pig endothelial cells in culture, ex vivo isolated pig liver perfusion and orthotopic transplantation of syngeneic rat livers. The addition of U74006F to University of Wisconsin preservation solution significantly prolonged endothelial cell viability after 48 and 72 hr of cold ischemia and reoxygenation (p < 0.01). Donor pigs were injected with vehicle or U74006F (4.5 mg/kg) before liver harvest. After 24 hr of cold storage in University of Wisconsin solution, the livers were perfused with pig blood for 180 min in an isolation chamber. Measurements of liver function parameters, including AST, ALT, bile production, superoxide anion and phospholipase A2 release, were assessed every 60 min. Although bile production was similar in the U74006F-treated and control groups, significant decreases of AST and ALT levels (p < 0.01) in the perfusate of the livers from treated donors were observed. In addition, the U74006F group displayed significantly reduced release of superoxide anion and phospholipase A2 compared with these parameters in the untreated group (p < 0.05 and p < 0.01, respectively). In the last model, donor rats were treated with U74006F before harvest; the rat liver grafts were preserved in cold University of Wisconsin solution for 24 hr and then transplanted into recipient rats.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Protective effect of the lazaroid U74006F in cold ischemia-reperfusion injury of the liver. 829 99

The number of clinical liver transplants that can be performed is limited by the availability of suitable donor organs. If it were possible to harvest and use livers after cardiac arrest, the supply could be improved. The mechanisms of damage in warm ischemia are not yet well understood and the consequences of transplanting a liver that is unable to provide immediate life-support are unacceptable. This study aims to identify areas for more detailed study in an attempt to improve the quality of livers harvested after significant warm ischemia, and to select acceptable organs for transplantation. Porcine livers were subjected to 75 min of warm ischemia and then perfused at 37 degrees C for 3 hr, during which period biochemical monitoring was carried out. At the end of the perfusion, histological and transmission electron microscopical studies were made. Large amounts of the intracellular enzymes ALT, AST, and LDH were released into the perfusate during the first 30 min of perfusion, but this--and the further amounts released during the subsequent 2.5 hr--was influenced by the composition of the perfusate. The inclusion of the substrates fructose and oleate, plus amino acids, substantially reduced this release and also improved the ability of the livers to metabolize ammonia. Oxygen free-radical scavengers had a significant, but smaller, beneficial effect. Electron microscopy confirmed the value of perfusion in improving cell morphology, and the additional value of including metabolic substrates. This study shows that hepatocellular structure and function can be improved by appropriate perfusion methods that also provide a simple means of monitoring some important functions. Both metabolic support and neutralization of oxygen free-radical action have a role to play in this approach to rendering ischemically injured livers acceptable for clinical use.
 ...
PMID:The possibility of resuscitating livers after warm ischemic injury. 833 57

Between September 1988 and November 1991, 201 donor hepatectomies and transplantations were performed. Fifty-four livers (26.9%) were harvested by other teams and shipped for transplantation; 147 livers (73.1%) were procured by teams from our transplant center. Comparing the maximal postoperative serum-aminotransferases (s-AT), we evaluated the postischemic damage of shipped organs (AST 951 +/- 931 IU/l; ALT 820 +/- 666 IU/l) and nonshipped organs (AST 753 +/- 1256 IU/l; ALT 636 +/- 896 IU/l); this did not differ significantly. Donor-related factors, such as critical parameters (i.e., cardiac arrest, arterial hypotension, age over 50 years, or elevated preoperative s-AT), length of stay in the intensive care unit before harvesting, and cause of death showed similar patterns in both groups. The mean cold ischemia time in the group of shipped livers (12 h 10 min +/- 4 h 22 min) and in the nonshipped livers (10 h 6 min +/- 3 h 53 min) did not differ significantly. Five cases (2.5%) of a primary non-functioning graft presenting with significantly (P < 0.001) elevated s-AT (AST 4944 +/- 2280 IU/l; ALT 3186 +/- 1918 IU/l) necessitated an early retransplantation. One organ was shipped and four organs were nonshipped, thus corresponding to their portion of all grafts. These data indicate that the transplantation of shipped livers is a safe procedure procedure, provided that procurement is done by experienced centers.
 ...
PMID:Transplantation of shipped donor livers. 834 65

Cell damage within the sinusoidal lining of human liver grafts during transplantation is an early event that is critical in ischemia-reperfusion injury and probably plays a key role in primary liver dysfunction after transplantation. No simple biochemical marker for sinusoidal injury is currently available. Because creatine kinase activity has been described in heart endothelial cells, we hypothesized that release of this enzyme might serve as an index of sinusoidal injury. To test this hypothesis, we used several in vivo and in vitro experimental models. Occlusion of the rat hepatic pedicle in situ for 60 min (normothermic ischemia) induced a significant increase in serum creatine kinase levels relative to those in laparotomized controls (2,530 +/- 530 vs. 389 +/- 64 IU/L, mean +/- SEM; p < 0.005). In the isolated perfused rat liver, 60-min ischemia induced early (< or = 3 min) creatine kinase and AST release (0.87 +/- 0.14 vs. 0.08 +/- 0.01 IU/min/gm liver, respectively). A similar phenomenon was observed after 24-hr or 48-hr hypothermic conservation in University of Wisconsin solution. Electrophoretic analysis and immunoinhibition studies showed that creatine kinase activity comprised creatine kinase-BB (approximately 50%) and mitochondrial creatine kinase. Trypan blue infusion showed a loss of viability in sinusoidal cells, whereas hepatocytes were relatively spared. Finally, murine sinusoidal cells were isolated, cultured and then lysed by a freeze-thaw cycle and sonication. Creatine kinase activity was found in endothelial cells (creatine kinase-BB), Kupffer cells (creatine kinase-BB) and Ito cells (creatine kinase-MM). Creatine kinase-BB was not found in hepatocytes, but mitochondrial creatine kinase was detected.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Creatine kinase-BB: a marker of liver sinusoidal damage in ischemia-reperfusion. 827 65


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