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)

Bacterial endotoxin (lipopolysaccharide; LPS) given to animals in large doses results in pronounced, midzonal liver injury. Exposure to smaller, non-injurious doses of LPS augments the toxicity of certain hepatotoxicants. This study was conducted to delineate the development of injury in a rat model of augmentation of aflatoxin B(1) (AFB(1)) hepatotoxicity by LPS. At large doses (i.e., > 1 mg/kg, ip), AFB(1) administration resulted in pronounced injury to the periportal regions of the liver. Male, Sprague-Dawley rats (250-350 g) were treated with 1 mg AFB(1)/kg, ip or its vehicle (0.5% DMSO/saline) and 4 h later with either E. coli LPS (7.4 x 106 EU/kg, iv) or its saline vehicle. Liver injury was assessed 6, 12, 24, 48, 72, or 96 h after AFB(1) administration. Hepatic parenchymal cell injury was evaluated as increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum and from histologic examination of liver sections. Biliary tract alterations were evaluated as increased concentration of serum bile acids and activities of gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), and 5'-nucleotidase (5'-ND) in serum. At all times and for all markers, injury in rats treated with either AFB(1) or LPS alone was absent or modest. In the AFB(1)/LPS cotreated group, hepatic parenchymal cell injury was pronounced by 24 h and had returned to control values by 72 h. The injury began in the periportal region and spread midzonally with time. Furthermore, changes in serum markers indicative of biliary tract alterations were evident by 12 h and had returned to control values by 72 h. Thus, the nature of the hepatic lesions suggested that LPS potentiated the effects of AFB(1) on both parenchymal and bile duct epithelial cells.
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PMID:Bacterial lipopolysaccharide exposure augments aflatoxin B(1)-induced liver injury. 1082 77

Dimethyl sulfoxide (DMSO) has previously been shown to have the ability to attenuate chloroform (CHCl(3))-induced liver injury in the naive rat even when administered 24 h after the toxicant. These studies were undertaken to determine if the protective action by late administration of DMSO is due to an inhibition of the bioactivation of CHCl(3). This was done by comparing the cytochrome P450 inhibitors, diallyl sulfide (DAS), and aminobenzotriazole (ABT) to DMSO for their protective efficacy when administered 24 h after CHCl(3) exposure. In addition, (14)CHCl(3) was utilized to measure the effect of DMSO and ABT on the covalent binding of CHCl(3) in the liver following their late administration. Male Sprague-Dawley rats (300-350 g) received 0.75 ml/kg CHCl(3) po. Twenty-four hours later, they received ip injection of 2 ml/kg DMSO, 100 mg/kg DAS, or 30 mg/kg ABT. Plasma ALT activities and quantitation of liver injury by light microscopy at 48 h after CHCl(3) dosing indicated that all three treatments were equally effective at protecting the liver. A detailed study of the time course of injury development indicated that the protective action of DMSO was occurring within 10 h of its administration. Therefore, in the radiolabel studies, rats were killed 24-34 h after receiving 0.75 ml/kg CHCl(3) (30 microCi/kg (14)CHCl(3)) po. Treatment with ABT at 24 h after (14)CHCl(3) dosing decreased the covalent binding of (14)C to hepatic protein by 35% and reduced the amount of (14)C in the blood by 50% by 10 h after its administration. DMSO treatment did not significantly affect any of these parameters. The lack of effect by late administration of DMSO on the covalent binding of CHCl(3) would indicate that DMSO may offer protection by mechanisms other than inhibition of the bioactivation of CHCl(3). These studies also indicate that specific cytochrome P450 inhibitors may be of benefit in clinical situations to help treat the delayed onset hepatitis that can result following poisoning with an organohalogen, even if the antidotes are administered a number of hours after the initial exposure.
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PMID:Hepatoprotection by dimethyl sulfoxide. III. Role of inhibition of the bioactivation and covalent bonding of chloroform. 1089 56

Acute aflatoxin B1 (AFB1)-induced hepatotoxicity was assessed in vivo in male Sprague-Dawley rats (150-300 g) using magnetic resonance imaging (MRI). MRI results were compared to serum enzyme levels, histology and electron microscopy. Twenty-four hours following intraperitoneal delivery of AFB1 (3 mg/kg body weight in a saline/dimethyl sulfoxide (DMSO; 0.03 ml/kg body weight) solution), regions of damage, characterised by increased proton signal intensities in T2-weighted images, were observed in the vicinity of the hepatic portal vein (HPV) and in the right medial regions of the liver. Image analysis of regions of apparent damage around the HPV and right medial regions, following 24 h of AFB1 exposure, indicated statistically significant (P<0.05) increases in proton image signal intensities, when compared to saline/DMSO-treated rats. No significant difference in proton image signal intensities were observed 1-2 h following AFB1 exposure. Twenty-four hours following AFB1 exposure, histopathological assessment was characterised by portal/central vein/artery congestion, sinusoid congestion, nuclear pyknosis and karyolysis, and hepatocyte vacuolation; electron microscopy (EM) examination indicated nuclear debris, swollen cytoplasmic compartments, vacuolation, and the disappearance of the smooth endoplasmic reticulum, and elevated levels of serum aspartate aminotransferase and alanine aminotransferase were found to be significantly different (P<0.01) than controls.
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PMID:Non-invasive in vivo magnetic resonance imaging assessment of acute aflatoxin B1 hepatotoxicity in rats. 1091 31

Exposure to small, noninjurious doses of the inflammagen, bacterial endotoxin (lipopolysaccharide, LPS) augments the toxicity of certain hepatotoxicants including aflatoxin B(1) (AFB(1)). Mediators of inflammation, in particular neutrophils (PMNs), are responsible for tissue injury in a variety of animal models. This study was conducted to examine the role of PMNs in the pathogenesis of hepatic injury after AFB(1)/LPS cotreatment. Male, Sprague-Dawley rats (250-350 g) were treated with either 1 mg AFB(1)/kg, ip or its vehicle (0.5% DMSO/saline), and 4 h later with either E. coli LPS (7. 4 x 10(6) EU/kg, iv) or its saline vehicle. Over a course of 6 to 96 h after AFB(1) administration, rats were killed and livers were stained immunohistochemically for PMNs. LPS resulted in an increase in PMN accumulation in the liver that preceded the onset of liver injury. To assess if PMNs contributed to the pathogenesis, an anti-PMN antibody was administered to reduce PMN numbers in blood and liver, and injury was evaluated. Hepatic parenchymal cell injury was evaluated as increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in serum and from histologic examination of liver sections. Biliary tract alterations were evaluated as increased concentration of serum bile acids and activities of gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), and 5'-nucleotidase (5'-ND) in serum. Neutrophil depletion protected against hepatic parenchymal cell injury caused by AFB(1)/LPS cotreatment but not against markers of biliary tract injury. This suggests that LPS augments AFB(1) hepatotoxicity through two mechanisms: one of which is PMN-dependent, and another that is not.
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PMID:Lipopolysaccharide augments aflatoxin B(1)-induced liver injury through neutrophil-dependent and -independent mechanisms. 1105 57

Troglitazone is a peroxisome proliferator-activated receptor-gamma agonist that has been shown to halt mesangium expansion in experimental models of type 2 diabetes mellitus and to act directly on rat mesangial cells. Because glutamine serves as the precursor for cellular biosynthetic processes, we asked whether troglitazone would inhibit mesangial cell glutamine metabolism under these conditions. Confluent monolayers of rat mesangial cells were incubated in RPMI medium in the presence of troglitazone or vehicle (DMSO). Troglitazone effected a dose-dependent reduction in glutamine utilization and in alanine formation, associated with a decrease in monolayer collagen-glycosaminoglycan content. Despite the reduced glutamine uptake, ammonium formation did not decrease, consistent with increased glutamate flux through the deamination pathway. Assayable activity of the alanine aminotransferase decreased by 63%, whereas assayable glutamate dehydrogenase remained unchanged. In control monolayers, the sum of ammonium plus alanine plus glutamate nitrogen released accounted for <75% of the glutamine nitrogen uptake. In troglitazone-treated monolayers, all of the glutamine nitrogen taken up could be accounted for as ammonium nitrogen released into the medium. These results are consonant with troglitazone reducing glutamine metabolism and specifically the transamination pathway in rat mesangial cells associated with a reduction in collagen-glycosaminoglycan content.
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PMID:Troglitazone inhibits glutamine metabolism in rat mesangial cells. 1173 5

Our previous studies have described the protective effects of hepatoprotective agents against liver injury elicited by chloroform even when given 24 h after the toxicant, at a time when the liver injury is taking place and rapidly developing. However, the mechanisms involved in this protection remain unknown. The cytoprotective mechanism of these hepatoprotectants such as DMSO, may be due to a dramatic shift in the production of prostaglandins that are responsible for controlling the degree of inflammatory response that can affect blood flow in the liver. In this study, NS-398, a specific COX-2 inhibitor, and indomethacin, a COX-1 and COX-2 inhibitor, were administered 24 h after chloroform dosing to determine their effect on liver injury in Sprague-Dawley rats. The extent of necrosis was evaluated by H&E staining, while injury to hepatocytes was evaluated by measuring plasma levels of alanine transaminase (ALT). Both COX inhibitors, indomethacin and NS-398, prevented an increase in (ALT) at 48 h after initial toxicant insult and attenuated further liver necrosis. No changes in cellular proliferative activity occurred in all the treatment groups, which indicates that protection from the Cyclooxygenase (COX) inhibitors did not have an effect on regeneration of cells at 32 and 48 h. These results indicate COX inhibitors provide a significant protective effect on liver cells against CHCl(3) injury and may provide further insight into therapeutic interventions against hepatotoxicants.
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PMID:Late administration of COX-2 inhibitors minimize hepatic necrosis in chloroform induced liver injury. 1250 47

The purpose of this study was to establish a set of techniques for cryopreservation of platelets with dimethylsulphoxide (DMSO) to insure high quality of cryopreserved platelet. The methods were as following: (1) DMSO was filtered in stead of being sterilized before infusion into the bag with platelets. (2) The whole blood was centrifuged immediately after blood collection and the attached tube was tied on the top of the bucket. (3) The related centrifugal force was 480 x g, the accelerating and braking grades of the centrifuge for acceleration and deceleration were 9 and 4 respectively. (4) The flow rate of platelet rich plasma (PRP) could not be too high, 80 - 100 ml PRP should be harvested at 1 minute or so. The infusion rate of DMSO into the PRP was 1 ml/min. After the infusion of DMSO, the PRP bag must be put into the -80 degrees C ultra low freezer at once to make the product to be freezed as soon as possible. The cryopreserved platelet should be thawed in the cycling warm water at the temperature of 38 - 40 degrees C. (5) After thawing of platelet, the platelet, red blood cell and white blood cell were counted, and the bacteria culturing, tests for HBsAg, anti-HCV, anti-HIV, TP and ALT were carried out. The results showed that altogether 14 800 units of cryopreserved platelets were prepared including 80 units collected with blood cell separator, of which quality control was accomplished in 300 units. The manually collected platelet mean count >/= 2.4 x 10(10)/unit, while the apheresis platelet count >/= 2.5 x 10(11)/unit. The yield was over 70%. The contaminated red and white blood cells were </= 1 x 10(9) and </= 1 x 10(7)/unit respectively. All the bacteria cultures were negative, while tests for HBsAg, anti-HCV, anti-HIV and TP were negative too. The ALT values were all in normal range. The transfusion of cryopreserved platelets showed obvious effect of haemostasis. In conclusion, the cryopreserved platelets prepared with this method were of high quality and efficaciousness in haemostasis clinically.
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PMID:[Effects of preparation and quality control of cryopreserved platelets]. 1536 45

The present study was performed to investigate the subacute effect of alpha-cypermethrin (alpha-CP) in rats. Alfacypermethrin a synthetic pyrethroid insecticide, dissolved in dimethyl sulfoxide (DMSO) and oral LD50 was investigated after administering orally different doses in rats and was determined as 145 mg/kg. Other groups of rats were given repeated daily oral dose (1/10 LD50) of alpha-CP for 30 days. The animals were sacrificed on 31st day. Activities of various enzymes, cytochrome P450 and b5 contents in liver, hepatic antioxidant status, tissue residue concentration, haemogram and pathological changes were studied. It increased the serum aminotransaminases (AST, ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) activities and blood glucose level significantly. alpha-CP decreased RBC count, PCV and Hb level significantly. It significantly decreased cytochrome P450 in liver. Residues were present in different tissues. It increased malondialdehyde (MDA) level, while decreased the activities of catalase (CAT), superoxide dismutase (SOD) and glycogen level in liver significantly. Mild to moderate histological alterations were observed in lungs, liver, stomach, kidneys, testes and cerebellum. So repeated daily oral doses of alpha-CP at 1/10LD50 altered the biochemical parameters, decreased cytochrome P450 content, antioxidant status, which correlated with histopathological changes of tissues.
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PMID:Repeated dose toxicity of alfa-cypermethrin in rats. 1536 39

We investigated the effect of raxofelast on lipid peroxidation inhibition in mice exposed to chronic ethanol. Female C57BL/6 mice were fed a modified Lieber-DeCarli liquid ethanol (ETOH) or control diet (sham ETOH) for up to 14 days. Animals were assigned to receive either raxofelast (20 mg/kg/day i.p.) or its vehicle (DMSO:NaCl 0.9% 1:1, v:v; 1 ml/kg i.p.). Serum alanine aminotransferase (ALT), plasma and liver triglyceride levels, hepatic malondialdehyde (MDA), reduced glutathione (GSH) concentrations, liver gene expression of Toll-like receptor-4 (TLR-4), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and intercellular adhesion molecule-1 (ICAM-1) were studied at the end of the study. A histological evaluation of liver damage was also carried out. Raxofelast, an analog of vitamin E, blunted the increased hepatic nuclear factor-kappaB activity, reduced serum ALT, plasma and liver triglycerides, lowered hepatic MDA levels, prevented liver GSH depletion and decreased TLR-4, TNF-alpha, IL-6 and ICAM-1 hepatic gene expression. Furthermore raxofelast ameliorated liver damage. Our results suggest that raxofelast blunts the inflammatory cascade and organ damage during chronic ethanol exposure.
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PMID:Protective effects of antioxidant raxofelast in alcohol-induced liver disease in mice. 1562 48

The effects of melatonin and dimethylsulfoxide (DMSO) on liver and brain oxidative stress, hepatic failure and blood urea nitrogen (BUN) level changes produced by a single dose of thioacetamide (TAA) in Wistar rats were studies. A dose of either melatonin (3 mg kg(-1)day(-1)) or DMSO (2 g kg(-1)day(-1)) was injected for 3 days before and for 2 days after the administration of TAA (150 mg kg(-1) i.p.). Blood samples were taken from the neck vascular in order to determine ammonium, BUN and liver enzymes. We estimated lipid peroxidation products, reduced glutathione (GSH) content and catalase activity in liver and brain homogenates. TAA caused significant increases in ammonium and in the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) enzymes, while it decreased BUN values. TAA also increased lipid peroxidation product levels, but reduced GSH content and catalase activity in the liver and brain. Both melatonin and DMSO, although melatonin more significantly, decreased the intensity of the changes produced by the administration of TAA alone. Furthermore, melatonin alone or combined with TAA increased the BUN levels and decreased the ammonia values compared with control animals. These results support the antioxidative and neuro-/hepato-protective action of melatonin and a lesser action of DMSO. Likewise, these data seem to support the hypothesis of an effect of melatonin on urea synthesis.
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PMID:Hepato- and neurotoxicity induced by thioacetamide: protective effects of melatonin and dimethylsulfoxide. 1589 75


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