Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.1 (aspartate aminotransferase)
21,665 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.
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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%.
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PMID:Serum lactic dehydrogenase in the differential diagnosis of acute hepatocellular injury. 796 56

To clarify the in vivo relevance of leukocyte-endothelial cell interactions in the manifestation of hepatic ischemia-reperfusion (I/R) injury, we studied leukocyte flow behavior in sinusoids and postsinusoidal venules of postischemic hepatic tissue in rats using intravital microscopy. Reperfusion following either 20 min (n = 9) or 60 min (n = 9) of left hepatic lobar ischemia resulted in a significant increase of the number of stagnant leukocytes in sinusoids and adherent cells in postsinusoidal venules compared with sham-operated controls (n = 10). Transmission electron microscopy revealed the extravasation of leukocytes from both sinusoids (into the space of Disse) and postsinusoidal venules. In parallel, hepatic I/R was associated with increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and reduced bile flow. Linear regression estimates revealed significant (P < 0.01) correlations between serum ALT (r = 0.76) and AST (r = 0.65) activities, bile flow (r = -0.62), and the number of adherent leukocytes in postsinusoidal venules. In contrast, parameters of hepatocellular integrity and function did not directly correlate with the number of stagnant leukocytes in liver sinusoids. We conclude that hepatic I/R induces accumulation, adherence, and extravasation of leukocytes in both hepatic sinusoids and postsinusoidal venules. However, the adherence of leukocytes to the endothelial lining of venules, rather than of sinusoids, may determine the manifestation of hepatocellular damage and liver dysfunction.
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PMID:Impact of leukocyte-endothelial cell interaction in hepatic ischemia-reperfusion injury. 797 40

This study investigated the effect of verapamil on prolonged and severe ischemic injury and elucidated the association of the calcium blocking action with cellular injury, assessing changes in hepatic calcium concentrations during ischemia and reperfusion in pigs. Hepatic ischemia was produced for 180 min by clamping both the hepatic artery and portal vein during temporary portacaval shunt performed before the induction of ischemia. Pigs were divided into two groups: the animals in the verapamil group (Group V, n = 6) received continuous administration of 0.025 mg/kg per min of verapamil intraportally for 20 min before ischemia. The control group (Group C) received nothing. A better survival rate was observed in Group V than in Group C (p < 0.01), but serum aspartate aminotransferase was higher in Group V after reperfusion (p < 0.05). There were no significant changes in hepatic calcium concentrations during ischemia in either group, but it increased immediately after reperfusion in both groups. However, no significant difference was found between the two groups. Recovery of the pyruvate/lactate ratio in Group V tended to be better after reperfusion compared to Group C (p = 0.08). These data suggest that the pre-ischemic administration of verapamil produced better survival in animals after prolonged normothermic ischemia. However, the reperfused liver suffered more severe damage in the first 6 h after reperfusion in the verapamil-treated animals. Moreover, there seemed to be very little blocking action of calcium influx. A reduced oxygen requirement may be involved in the protective action of verapamil on animal survival.
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PMID:Effect of verapamil on hepatic reperfusion injury after prolonged ischemia in pigs. 798 12

Hepatic ischemia-reperfusion (I/R) is characterized by circulatory and metabolic derangements, liver dysfunction, and tissue damage. However, little is known about the causative role of I/R-induced microcirculatory disturbance on the manifestation of postischemic reperfusion injury. Therefore, the intention of the study was to assess changes of hepatic microvascular perfusion (intravital fluorescence microscopy) as related to hepatic morphology (light/electron microscopy), hepatocellular integrity (serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities), and excretory function (bile flow). Sprague-Dawley rats were subjected to 20 minutes (group B, n = 9) and 60 minutes (group C, n = 9) of left hepatic lobar ischemia followed by 60 minutes of reperfusion. Sham-operated animals without ischemia served as controls (group A, n = 10). Lobar ischemia for 20 minutes followed by reperfusion resulted in a significant reduction of sinusoidal perfusion rate (93.9 +/- 1.4%; P < 0.05) and a decrease in erythrocyte flux (90.0 +/- 5.6%) when compared with controls (99.4 +/- 0.2 and 97.9 +/- 2.7%). This was accompanied by a significant increase of serum AST and ALT activities (P < 0.05) and a reduction of bile flow (P < 0.05). Prolongation of lobar ischemia (group C, 60 minutes) aggravated postischemic reperfusion injury (sinusoidal perfusion rate: 87.4 +/- 2.9%; erythrocyte flux: 62.1 +/- 8.4%) and was paralleled by severed hepatocellular damage. Electron microscopy of postischemic tissue demonstrated alteration of nonparenchymal cells (swelling of sinusoidal lining cells and widening of Disse's space) and substantial parenchymal cell damage (swelling of mitochondria, disarrangement of rough endoplasmatic reticulum, vacuolization, complete cytoplasmic degeneration). Initial postischemic increase in serum AST and ALT activities and reduction of bile flow directly correlated with the extent of microcirculatory failure (P < 0.01), ie, impairment of sinusoidal perfusion and decrease of erythrocyte flux, indicating the decisive role of microvascular perfusion failure for the manifestation of hepatic tissue damage and liver dysfunction.
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PMID:Hepatic microcirculatory perfusion failure is a determinant of liver dysfunction in warm ischemia-reperfusion. 799 45

This study was designed to examine the role of Kupffer cells in polymorphonuclear neutrophils (PMN) activation and infiltration after severe total hepatic ischemia. Male rats pretreated with either normal saline (NS group; n = 58) or gadolinium chloride (7 mg/kg; GC group, n = 57) for 2 days were subjected to 90 min total hepatic ischemia. In addition to 7-day survival rate, aspartate aminotransferase (AST), PMN liver infiltration, plasma myeloperoxidase (MPO), and interleukin-1 (IL-1) levels were serially measured from the end of ischemia to 360 min after reperfusion. Survival rate of the GC group significantly improved to 67% (P < 0.01), whereas that of the NS group remained at 20%. Extremely high AST levels (5,372 +/- 231 IU/liter) were obtained in the NS group, which correlated with the degree of hepatic necrosis. Very high IL-1 (270.3 +/- 91.2 pg/ml) and MPO (1.7 +/- 0.4 U/ml) levels were also seen in the NS group. The GC group significantly inhibited increases in AST, IL-1, and MPO levels as well as PMN infiltration in the liver compared to the NS group (P < 0.05). Our study demonstrated that Kupffer cell activation has an important role in the development of reperfusion injury after total hepatic ischemia through IL-1 release, and PMN activation and infiltration.
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PMID:Role of Kupffer cells in neutrophil activation and infiltration following total hepatic ischemia and reperfusion. 805 66

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.
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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)
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PMID:Donor criteria in hepatic transplantation. 814 13

Although the liver is relatively resistant to normothermic ischemia, prolonged periods of inflow occlusion have produced evidence of hepatocyte injury. We have developed an animal model of liver ischemia using the pig and maintaining subtotal inflow (hepatic artery and portal vein) occlusion, allowing mesenteric portal decompression via patent portal veins through the caudate lobe, obviating the need for portosystemic shunting. This produced biochemical [aspartate transaminase (AST), lactate dehydrogenase (LDH)] and histopathologic evidence, using a microscopic grading system, of hepatocyte necrosis after 2 hr of normothermic ischemia. By administration of prostaglandin E1 (PGE1) prior to and during inflow occlusion, we have produced a statistically significant reduction in LDH (1085.9 +/- 413.5 U/liter compared to 669.1 +/- 161.4 U/liter) and AST (236.5 +/- 80.4 U/liter compared to 85.1 +/- 39.7 U/liter) (P < 0.05) between control and PGE1 animals 24 hr after reperfusion. Moreover, using the blinded microscopic grading system for hepatocellular necrosis, we have found significantly less (2.86 +/- 0.90 compared to 1.57 +/- 1.13, P < 0.01) necrosis when control and PGE1 animals were compared. Our experimental model supports the hypothesis that PGE1 exerts a cytoprotective effect during prolonged normothermic hepatic ischemia but does not aid in elucidating a mechanism for this effect.
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PMID:Evidence for cytoprotection by prostaglandin E1 with normothermic hepatic ischemia. 815 23

Cardiopulmonary and other organ dysfunction often occurs after operation on the descending thoracic aorta. Though there are multiple causes of organ dysfunction in this setting, free radical injury may play a prominent role. Xanthine oxidoreductase, an enzyme that generates oxidants after exposure to ischemia, could be released from ischemic liver and intestine during reperfusion. To test this hypothesis, we created aortic occlusion in eight rabbits for 40 minutes by inflation of a 4F Fogarty balloon catheter in the descending thoracic aorta. Eight sham-operated rabbits served as a control group. Two hours of reperfusion followed removal of the balloon catheter. Hemodynamic and acid-base status were maintained near baseline values during reperfusion. Plasma samples were obtained for determination of the activity of the hepatocellular enzymes xanthine oxidoreductase, aspartate aminotransferase, alanine transferase, and lactate dehydrogenase. Plasma xanthine oxidoreductase activity increased significantly (p < 0.001) during reperfusion (729 +/- 140 microU/ml, mean +/- standard error of the mean) compared with baseline (132 +/- 18 microM/mL). The other enzymes followed a similar pattern of release. We report the release of xanthine oxidoreductase in an animal model that simulates the situation of human thoracic aorta operations. The oxidants produced by the circulating xanthine oxidoreductase observed during reperfusion would likely be toxic to vascular endothelium, potentially contributing to multiple organ dysfunction.
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PMID:Xanthine oxidoreductase release after descending thoracic aorta occlusion and reperfusion in rabbits. 817 64


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