Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with obstructive jaundice (OJ) that requires surgery often have malnutrition associated with increased perioperative morbidity. This study investigated the factors influencing nutritional derangements in these patients. A series of 46 OJ patients were investigated prospectively (28 malignant tumors, 18 benign obstructions). A nutritional risk index of < 83.5 was used to define protein-calorie malnutrition. Liver function, cholecystokinin (CCK), tumor necrosis factor-alpha (TNFalpha), and endotoxin levels were determined. A multivariate analysis was performed, and an obstructive jaundice malnutrition index (OJMI) was obtained. Altogether, 22 (48%) OJ patients had malnutrition (33% with benign obstructions, 57% with malignant disease). Malnourished patients had higher serum bilirubin levels (258 +/- 120 vs. 154 +/- 62 mmol/L; p = 0.005), longer duration of jaundice (16 +/- 9 vs. 9 +/- 5 days; p = 0.03), and higher plasma levels of CCK (4.0 +/- 1.3 vs. 1.7 +/- 1.0 pmol/L; p = 0.005), alanine aminotransferase (ALT) (226 +/- 209 vs. 187 +/- 161 UI/L; p = 0.01), endotoxin (15 +/- 10 vs. 6.5 +/- 7.0 EU/L; p = 0.007), and TNFalpha (69 +/- 82 vs. 23 +/- 15 pg/ml; p = 0.008) than those without malnutrition. However, only serum bilirubin, CCK, ALT, and patient age were predictors for malnutrition by multivariate analysis. Malnutrition might be expected (95% confidence interval) in patients older than 68 years with increased bilirubin (> 290 mmol/L) and ALT (> 210 UI/L) levels that corresponded with an OJMI > 55. It was concluded that nutritional alterations in patients with obstructive jaundice were determined by the intensity of the biliary obstruction correlated with increased plasma CCK levels as well as with liver dysfunction and patient age.
 ...
PMID:Factors predicting nutritional derangements in patients with obstructive jaundice: multivariate analysis. 1134 90

Fatty livers are sensitive to lipopolysaccharide (LPS) damage. This study tests the hypothesis that this vulnerability occurs because protective, antiapoptotic mechanisms are not upregulated appropriately. Genetically obese, leptin-deficient ob/ob mice, a model for nonalcoholic fatty liver disease, and their lean litter mates were treated with a small dose of LPS. General measures of liver injury, early (i.e., cytochrome c release) and late (i.e., activation of caspase 3) events that occur during hepatocyte apoptosis, and various aspects of the signal transduction pathways that induce nuclear factor-kappaB (NF-kappaB) and several of its antiapoptotic transcriptional targets (e.g., inducible nitric oxide synthase, bfl-1, and bcl-xL) were compared. Within 0.5-6 h after LPS exposure, cytochrome c begins to accumulate in the cytosol of normal livers, and procaspase 3 cleavage increases. Coincident with these events, kinases (e.g., AKT and Erk-1 and -2) that result in the degradation of inhibitor kappa-B are activated; NF-kappaB activity is induced, and NF-kappaB-regulated gene products accumulate. Throughout this period, there is negligible histological evidence of liver damage, and serum alanine aminotransferase values barely increase over baseline values. Although ob/ob livers have significant histological liver injury and 11-fold greater serum alanine aminotransferase values than those of lean mice by 6 h post-LPS, they exhibit greater activation of AKT and Erk, more profound reductions in inhibitor kappa-B, enhanced activation of NF-kappaB, and greater induction of NF-kappaB-regulated genes. Consistent with this heightened antiapoptotic response, increases in cytochrome c and procaspase 3 cleavage products are inhibited. Together with evidence that ob/ob hepatocytes have a reduced ATP content and undergo increased lysis after in vitro exposure to tumor necrosis factor-alpha, these findings suggest that fatty livers are sensitive to LPS damage because of vulnerability to necrosis, rather than because of apoptosis.
 ...
PMID:Fatty liver vulnerability to endotoxin-induced damage despite NF-kappaB induction and inhibited caspase 3 activation. 1144 19

To elucidate the suppressive effects of energy restriction on the inflammatory responses to lipopolysaccharide (LPS), mice were divided into a control group (fed 5.0 g diet/d; 71 kJ/d) and a 40% energy-restricted group (fed 3.0 g diet/d; 43 kJ/d) at 8-wk of age. Four weeks later, 25 microg of LPS was intraperitoneally injected. After the LPS injection, interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha were elevated in serums in the 40% energy-restricted mice and in the controls, but the extent of the elevation was significantly lower in the restricted group. The LPS-induced expression of inducible nitric oxide synthase in the liver was significantly suppressed by the energy restriction. In addition, the LPS-induced elevations of serum aspartate and alanine aminotransferase activities, which are indexes of hepatic injury, were also significantly attenuated in the restricted group. Moreover, the extent of LPS-induced alterations in hepatic structure was less in the restricted mice than in controls. Serum corticosterone level in the restricted mice was higher than that in the controls before LPS treatment (P < 0.05). Furthermore, after LPS injection, the significantly higher level of corticosterone was maintained in the restricted mice, although the LPS treatment significantly enhanced the level even in the control group. These results suggest that the extreme inflammatory responses to endotoxin are prevented in the 40% energy-restricted mice, and corticosterone participates in the preventive effects.
 ...
PMID:Inflammatory responses to lipopolysaccharide are suppressed in 40% energy-restricted mice. 1148 8

Macrophage-derived inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha), have been shown to play a central role in aggravation of acute pancreatitis (AP), but little is known about their roles in liver injury. We investigated the pathogenesis of the liver injury in AP and assessed the efficacy of arterial infusion of an antibiotic via the superior mesenteric artery (SMA). Infusion of saline (group A) or imipenem (group B) was started 6 hours after induction of AP in dogs by intraductal administration of autologous gallbladder bile. The survival rate in group B was significantly improved compared with group A. Serum alanine aminotransferase levels in peripheral blood and endotoxin levels in portal vein blood were both significantly higher at 18 hours in group A than in group B. When hepatocytes and Kupffer cells were isolated at 18 hours and cultured for 24 hours thereafter, there was significant exacerbation of the hepatocyte injury and significantly greater production of TNF-alpha in the coculture of hepatocytes and Kupffer cells in group A, indicating that the Kupffer cells had been activated. By contrast, both of these manifestations were significantly mitigated in group B. These findings suggest that TNF-alpha secreted by endotoxin-activated Kupffer cells contributes to liver injury in AP, and that SMA infusion of an antibiotic mitigates the liver injury by controlling endotoxin translocation.
 ...
PMID:Liver injury in acute pancreatitis and mitigation by continuous arterial infusion of an antibiotic via the superior mesenteric artery. 1148 23

Hepatic Kupffer cells and pulmonary alveolar macrophages together constitute a macrophage-axis involved in the regulation of regional and systemic inflammatory responses. Systemic inflammatory response syndrome induced by overproduced pro-inflammatory mediators is the major cause of adult respiratory distress syndrome. In the present study, we examined the anti-inflammatory role of nitric oxide (NO) in a rat model of acute lung injury induced by hepatic ischemia-reperfusion (HI/R). The left and median lobes of the liver were subjected to 30 min of ischemia by clamping the relevant branches of hepatic artery and portal vein, followed by a 4-h reperfusion achieved by removal of the vascular clamp. Four groups of animals were studied: sham control + saline; sham control + N(omega)-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg, i.v., 10 min before reperfusion); HI/R + saline; HI/R + L-NAME. Results show that (1) administration of L-NAME to rats subjected to HI/R decreased plasma NO levels; however, the attenuation of NO increased plasma alanine aminotransferase (ALT) activity and superoxide generation in the ischemic lobes of liver, compared to HI/R alone. (2) Inhibition of NO synthesis with L-NAME in rats subjected to HI/R also enhanced systemic inflammatory response as assessed by the increase in the number of circulating leukocytes and levels of plasma tumor necrosis factor-alpha (TNFalpha) and interleukin 1-beta (IL-1beta). (3) The overwhelming systemic inflammatory response induced by administration of L-NAME in rats subjected to HI/R also augmented pulmonary vascular permeability and superoxide generation in the lung tissue. (4) Pulmonary alveolar macrophages isolated from rats subjected to HI/R + L-NAME produced higher levels of TNFalpha and IL-1beta in the supernatant of culture medium than that of rats subjected to HI/R alone. (5) There were no differences between the groups of sham + saline and sham + L-NAME in terms of plasma NO levels and ALT activity, circulating leukocytes, superoxide generation in the liver and lung, lavage protein levels, and TNFalpha and IL-1beta levels in plasma and bronchoalveolar lavage fluid. Our results suggest that inhibition of NO synthesis by L-NAME in rats subjected to HI/R not only augments ischemic liver injury, but also enhances the systemic inflammatory response and exacerbates remote lung injury. The increase in TNFalpha and IL-1beta production by alveolar macrophages may, in part, account for L-NAME-induced enhancement of acute lung injury.
 ...
PMID:Inhibition of nitric oxide synthesis by L-name exacerbates acute lung injury induced by hepatic ischemia-reperfusion. 1153 Oct 23

Excessive apoptosis has been implicated in a number of acute and chronic human diseases. The activation of caspases has been shown to be critical for the apoptotic process. The objective of this investigation was to evaluate the beneficial effects and mechanism of action of the caspase-8 inhibitor IETD-CHO and the caspase-3 inhibitor DEVD-CHO against tumor necrosis factor (TNF)-induced hepatocellular apoptosis in vivo and compare these results to effects of the same inhibitors against Fas-induced apoptosis. Treatment of C3Heb/FeJ mice with 700 mg/kg galactosamine/100 microg/kg endotoxin induced parenchymal apoptosis (indicated by caspase-3 activation and morphology) and severe liver injury (indicated by the increase in plasma alanine aminotransferase activities and histology) at 7 h. Treatment with IETD-CHO or DEVD-CHO (10 mg/kg at 3, 4.5, and 5.5 h) significantly attenuated caspase-3 activation and liver injury. Western analysis showed that DEVD-CHO had no effect while IETD-CHO substantially reduced procaspase-3 and procaspase-9 processing. On the other hand, caspase-3 activation and liver injury by the anti-Fas antibody Jo-2 was completely prevented by a single dose of DEVD-CHO and, as previously shown, by IETD-CHO at 90 min. Both inhibitors prevented procaspase-3 and procaspase-9 processing. Thus, there are fundamental differences in the efficacy of caspase inhibitors in these two models. We conclude that Fas may rely exclusively on caspase-8 activation and mitochondria to activate caspase-3, which can process more procaspase-8 and thus propagate the amplification of the apoptotic signal. TNF can activate a similar signaling pathway. However, alternative signaling mechanisms seem to exist, which can compensate if the main pathway is blocked.
 ...
PMID:Differential protection with inhibitors of caspase-8 and caspase-3 in murine models of tumor necrosis factor and Fas receptor-mediated hepatocellular apoptosis. 1155 23

We evaluated the efficacy of ONO-4819, a newly developed agonist of a prostaglandin receptor subtype (EP4), on experimental model of acute liver injury in rats. Acute liver injury was induced by simultaneous intraperitoneal (i.p.) administration of D-galactosamine (GalN, 1 g/kg body weight) and lipopolysaccharide (LPS, 100 mg/kg body weight). The rats received a single intraperitoneal injection of ONO-4819 (0.2 mg/kg body weight) or physiological saline immediately after GalN/LPS administration. Submassive hepatic necrosis with marked elevation of serum total bilirubin, serum aspartate aminotransferase and serum alanine aminotransferase levels developed 24 h after GalN/LPS administration. The administration of ONO-4819 significantly inhibited the development of submassive hepatic necrosis and inhibited the elevation in levels of biochemical markers that indicate liver function. In addition, the apoptotic index of hepatocytes assessed by the TUNEL method was significantly lower in rats treated with ONO-4819 than in the control. Although serum levels of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and interleukin-8 (IL-8) were markedly elevated after GalN/LPS administration, ONO-4819 significantly inhibited the elevation of those of TNF-alpha and IFN-gamma but not that of IL-8. The beneficial effect of ONO-4819 for acute liver injury was similar at doses of 0.1, 0.05 and 0.01 mg/kg body weight. These results suggest that the EP4 agonist, ONO-4819, may have a protective effect against experimental liver injury in rats through the suppression of inflammatory cytokines.
 ...
PMID:A novel prostaglandin E receptor subtype agonist, 0N0-4819, attenuates acute experimental liver injury in rats. 1167 10

Oltipraz is a cancer chemopreventive agent active against a wide variety of chemical carcinogens. In spite of the intense chemoprevention and toxicology studies on oltipraz, no information is available on its antifibrotic efficacy. In the present study, the effects of oltipraz on dimethylnitrosamine (DMN)-induced liver fibrogenesis were assessed in rats. As part of mechanistic studies, the expression of transforming growth factor-beta1 (TGF-beta1) and tumor necrosis factor-alpha (TNF-alpha) was monitored. Treatment of rats with DMN (10 microl/kg body weight, i.p., three times per week for 4 weeks) resulted in marked increases in plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (gamma-GT) activities. DMN also caused an increase in the plasma bilirubin content, whereas total plasma protein and albumin levels were rather decreased. Oltipraz (50 mg/kg body weight, p.o., three times per week for 4 weeks) inhibited the increases in plasma ALT, AST, gamma-GT and bilirubin by DMN. DMN increased liver fibrosis as histopathologically assessed by Van Gieson's staining and Masson's trichrome staining (fibrosis score, 3.7; Knodell score, 16), which was reduced by oltipraz treatment (fibrosis score, 2.5; Knodell score, 8.0). Reverse transcription-polymerase chain reaction analysis revealed that oltipraz inhibited an increase in the TGF-beta1 mRNA by DMN. Oltipraz was also active in reducing the production of plasma TNF-alpha by DMN or lipopolysaccharide (LPS), which would contribute to its cytoprotective effect. These results demonstrated that oltipraz inhibited hepatocyte injury and impairment of liver function induced by DMN, and reduces DMN-induced liver fibrosis possibly through suppression of TGF-beta1 and TNF-alpha production.
 ...
PMID:Inhibition of dimethylnitrosamine-induced liver fibrosis by [5-(2-pyrazinyl)-4-methyl-1,2-dithiol-3-thione] (oltipraz) in rats: suppression of transforming growth factor-beta1 and tumor necrosis factor-alpha expression. 1180 29

T-cell hyporesponsiveness may lead to chronicity of hepatitis C virus (HCV) infection. We evaluated whether interferon (IFN)-gamma injection can bring a Th1-dominant environment to patients with chronic hepatitis C. Seventeen patients with genotype 1b received natural IFN-alpha 5MU daily for the first 2 weeks and three times a week for the next 22 weeks followed by natural IFN-gamma 1 MU daily for 2 weeks. In 4 of 17 patients (23.5%), alanine aminotransferase (ALT) was normalized and 3 of these 4 patients (75.0%) cleared HCV RNA. beta2 microglobulin (BMG), neopterin and soluble (s) Fas increased with IFN-alpha and increased more with IFN-gamma. Serum interleukin (IL)-12, CD4 and CD8 remained unchanged with IFN-alpha but increased after IFN-alpha was replaced by IFN-gamma. IL-10 was not changed either with IFN-alpha or gamma. Productions of IL-2, IFN-gamma and tumor necrosis factor (TNF)-alpha by peripheral blood mononuclear cells did not change by IFN-alpha therapy, however, they were enhanced at the end of IFN-gamma therapy. Productions of IL-2 and 4 were unaffected. These results show that some immune parameters become Th1-dominant by additional IFN-gamma in patients with chronic hepatitis C. Combination of these two IFNs should be explored.
 ...
PMID:Interferon-gamma brings additive anti-viral environment when combined with interferon-alpha in patients with chronic hepatitis C. 1180 30

Although ethanol is known to sensitize hepatocytes to tumor necrosis factor (TNF) lethality, the mechanisms involved remain controversial. Recently, others have shown that adding TNFalpha to cultures of ethanol-pretreated hepatocytes provokes the mitochondrial permeability transition, cytochrome c release, procaspase 3 activation, and apoptosis. Although this demonstrates that ethanol can sensitize hepatocytes to TNF-mediated apoptosis, the hepatic inflammation and ballooning hepatocyte degeneration that typify alcohol-induced liver injury suggest that other mechanisms might predominate in vivo. To evaluate this possibility, acute responses to lipopolysaccharide (LPS), a potent inducer of TNFalpha, were compared in mice that had been fed either an ethanol-containing or control diet for 5 weeks. Despite enhanced induction of cytokines such as interleukin (IL)-10, IL-15, and IL-6 that protect hepatocytes from apoptosis, ethanol-fed mice exhibited a 4-5-fold increase in serum alanine aminotransferase after LPS, confirming increased liver injury. Six h post-LPS histology also differed notably in the two groups, with control livers demonstrating only scattered apoptotic hepatocytes, whereas ethanol-exposed livers had large foci of ballooned hepatocytes, inflammation, and scattered hemorrhage. No caspase 3 activity was noted during the initial 6 h after LPS in ethanol-fed mice, but this tripled by 1.5 h after LPS in controls. Procaspase 8 cleavage and activity of the apoptosis-associated kinase, Jun N-terminal kinase, were also greater in controls. In contrast, ethanol exposure did not inhibit activation of cytoprotective mitogen-activated protein kinases and AKT or attenuate induction of the anti-apoptotic factors NF-kappaB and inducible nitric oxide synthase. Consistent with these responses, neither cytochrome c release, an early apoptotic response, nor hepatic oligonucleosomal DNA fragmentation, the ultimate consequence of apoptosis, was increased by ethanol. Thus, ethanol exacerbates TNF-related hepatotoxicity in vivo without enhancing caspase 3-dependent apoptosis.
 ...
PMID:Chronic ethanol exposure potentiates lipopolysaccharide liver injury despite inhibiting Jun N-terminal kinase and caspase 3 activation. 1181 69


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