Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cell wall of Streptococcus mitis biovar 1 strain SK137 contains the C-polysaccharide known as the common antigen of a closely related species Streptococcus pneumoniae, and a teichoic acid-like polysaccharide with a unique structure. The two polysaccharides are different entities and could be partially separated by gel chromatography. The structures of the two polysaccharides were determined by chemical methods and by NMR spectroscopy. The teichoic acid-like polymer has a heptasaccharide phosphate repeating unit with the following structure: The structure neither contains ribitol nor glycerol phosphate as classical teichoic acids do, thus we have used the expression teichoic acid-like for this polysaccharide. The following structure of the C-polysaccharide repeating unit was established: where AAT is 2-acetamido-4-amino-2,4, 6-trideoxy-D-galactose. It has a carbohydrate backbone identical to that of one of the two structures of C-polysaccharide previously identified in S. pneumoniae. C-polysaccharide of S. mitis is characterized by the presence, in each repeating unit, of two residues of phosphocholine and both galactosamine residues in the N-acetylated form. Immunochemical analysis showed that C-polysaccharide constitutes the Lancefield group O antigen. Studies using mAbs directed against the backbone and against the phosphocholine moiety of the C-polysaccharide revealed several different patterns of these epitopes among 95 S. mitis and Streptococcus oralis strains tested and the exclusive presence of the group O antigen in the majority of S. mitis biovar 1 strains.
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PMID:Structures of two cell wall-associated polysaccharides of a Streptococcus mitis biovar 1 strain. A unique teichoic acid-like polysaccharide and the group O antigen which is a C-polysaccharide in common with pneumococci. 1110 26

Birds have evolved alternate physiologic strategies to contend with dehydration, starvation, malnutrition, and reproduction. Basic anatomic and functional differences between birds and mammals impact clinical chemistry values and their evaluation. Interpretation of the results of standard biochemical analyses, including BUN, alanine aminotransferase, aspartate aminotransferase, creatine kinase, gamma glutamyltransferase, bilirubin, ammonia, alkaline phosphatase, cholesterol, bile acids, glucose, albumin, globulins, calcium, phosphorus, prealbumin (transthyretin), fibrinogen, iron, and ferritin, is reviewed and discussed in relation to these physiological differences. The use and interpretation of alternative analytes appropriate for avian species, such as uric acid, biliverdin, glutamate dehydrogenase, and galactose clearance, also are reviewed. Normal avian urine and appropriate use of urinalysis, an integral part of laboratory diagnosis in mammalian species that frequently is omitted from avian diagnostic protocols, is discussed.
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PMID:Clinical chemistry of companion avian species: a review. 1218 2

Incubation of 50 mM D-glucose with aspartate aminotransferase (AST, EC 2.6.1.1) preparations (purified pig heart enzyme or a rat liver 20,000 x g supernatant) at 25 degrees C had no effect on enzyme activity. 50 mM D-fructose or D-ribose gradually inhibited pig heart AST under the same conditions to zero activity after 14 days. 50 mM DL-glyceraldehyde decreased enzyme activity to zero after 6 days of incubation. The inhibition of pig heart AST by 50 mM D-fructose or D-ribose was marked even at a temperature of 4 degrees C but it was less pronounced than at 25 degrees C. There was no effect of 0.5 mM 2-oxoglutarate on AST activity during incubation, while the presence of 25 mM L-aspartate decreased it rapidly. 0.5 mM 2-oxoglutarate partly prevented inhibition of AST by D-ribose or D-fructose, while an analogous experiment with 25 mM aspartate resulted in a rapid decline similar to that in the absence of sugars.
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PMID:Inhibition of aspartate aminotransferase by glycation in vitro under various conditions. 1236 58

Streptococcus mitis strain SK598, which represents a subgroup of biovar 1, possesses a unique variant of the C-polysaccharide found in the cell wall of all strains of Streptococcus pneumoniae and in some strains of S. mitis. This new variant lacks the choline methyl groups in contrast to the previously characterized forms of C-polysaccharide, which all contain one or two choline residues per repeat. The following structure of the repeating unit of the SK598 polysaccharide was established: where AAT is 2-acetamido-4-amino-2,4,6-trideoxy-d-galactose. This structure is identical to the double choline-substituted form of C-polysaccharide, except that it is substituted with ethanolamine instead of choline. This extends the number of recognized C-polysaccharide variants to four.
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PMID:A unique variant of streptococcal group O-antigen (C-polysaccharide) that lacks phosphocholine. 1275 35

The association of hyperglycemia and markers of hepatic dysfunction with dextrose infusion rates in Korean patients receiving total parenteral nutrition (TPN) was studied. A retrospective study of 122 patients with normal glucose levels and liver function tests (LFTs) was conducted. Pharmacy and medical records of all patients who received TPN from three university-affiliated teaching hospitals in Korea between January 1998 and December 1999 were reviewed. Each patient was categorized as receiving dextrose at (1) < or = 5 or > 5 mg/kg/min and (2) < or = 4, 4.1-5, 5.1-6, or > 6 mg/kg/min. Fifty-five patients received dextrose at a rate of > 5 mg/kg/min for 15.1 +/- 12.8 days and 67 patients at a rate of < or = 5 mg/kg/min for 10.1 +/- 6.8 days. Two patients in each group did not have follow-up glucose levels. Of the 53 patients in the > 5 mg/kg/min group, 16 exhibited hyperglycemia, compared with 21 of the 65 receiving lower rates of dextrose infusion. Elevated aspartate transaminase was the most common abnormal LFT value in both groups (25% and 29% in the < or = 5- and > 5-mg/kg/min groups, respectively). In the group receiving dextrose at > 5 mg/kg/min, 22.2% had two hepatic enzyme levels elevated concurrently, while 18.5% had two hepatic enzyme levels elevated in the group receiving dextrose at < or = 5 mg/kg/min. Regression analysis revealed that duration of TPN and dextrose infusion rate were positively correlated with blood glucose levels and that duration of TPN was positively correlated with abnormal LFT values. A retrospective study of Korean patients revealed no significant difference in the risk of hyperglycemia or hepatic dysfunction between those receiving < or = 5 and > 5 mg/kg/min dextrose infusion in their TPN.
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PMID:Association of hyperglycemia and markers of hepatic dysfunction with dextrose infusion rates in Korean patients receiving total parenteral nutrition. 1450 12

Controversy exists over whether the predominant cell death of hepatocytes is due to apoptosis or necrosis after ischemia/reperfusion injury. In this study we investigated the predominant cell death of hepatocytes after cold ischemia/reperfusion injury using the Annexin V-based assay, and evaluated the anti-apoptotic effect of ascorbic acid 2-glucoside (AA-2G) added to the University of Wisconsin solution (UW solution) in rat liver transplantation. The retrieved liver was preserved in 4 UW solution for 24 h, and then transplanted orthotopically to the syngeneic Wistar recipient. The animals were divided into 2 groups, a control group (n=10), in which liver grafts were preserved in UW solution (4), and an AA-2G group (n=10), in which liver grafts were preserved in UW solution (4) with AA-2G (100 ug/ml). The serum AST level 4 h after reperfusion in the control group was significantly suppressed in the AA-2G group, and the bile production of the liver graft in the AA-2G group was well recovered. The mean survival time in the AA-2G group was significantly improved compared with that in the control group. Annexin-V and Propidium iodide staining 4 h after reperfusion showed a significantly higher percentage of viable hepatocytes in the AA-2G group compared with the control group (93.4 +/- 2.0 vs. 80.3 +- 2.1%, P<0.05). In the control group, the main cell death of hepatocytes was apoptosis (early apoptosis: 10.0 +- 4.7%, late apoptosis: 6.4 +/- 1.7%). The addition of AA-2G to the UW solution significantly inhibited both early and late apoptotic cell death 4 h after reperfusion (early apoptosis: 0.98 +/- 0.88%, late apoptosis: 2.2 +/- 1.1%). The expression of caspase 9 in the immunostaining of the liver graft was suppressed in the AA-2G group compared with in the control group. Our study using the Annexin V-based assay provided evidence that the predominant cell death of hepatocytes was apoptosis after 24 h cold ischemia/reperfusion injury in rat liver transplantation. The addition of AA-2G to the UW solution attenuated 24 h cold ischemia/reperfusion injury by inhibiting the apoptosis of hepatocytes.
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PMID:Annexin V assay-proven anti-apoptotic effect of ascorbic acid 2-glucoside after cold ischemia/reperfusion injury in rat liver transplantation. 1467 98

The purpose of this study was to assess the antifungal activity and renal and hepatic toxicity of amphotericin B lipid complex (ABLC; Abelcet) following co-administration of Caspofungin to rats infected with Aspergillus fumigatus. Aspergillus fumigatus inoculum (1.3-2.3 x 10(7) colony forming units [CFU]) was injected via the jugular vein; 48 h later male albino Sprague-Dawley rats (350-400 g) were administered either a single intravenous (i.v.) dose of Fungizone(R) (1 mg AmpB/kg), ABLC (1 or 5 mg AmpB/kg), or an equivalent volume of normal saline (NS) (vehicle control) once daily for 4 days. Rats were further randomized into groups to receive 3 mg/kg Caspofungin or physiologic saline i.v. once daily for 4 days. To assess antifungal activity, brain, lung, heart, liver, spleen, and kidney sections were homogenized with NS (2 mL; 1 g of each tissue/mL) and a 0.1-mL aliquot was spread plated onto a Sabouraud dextrose agar plate. The plates were incubated for 48 h at 37 degrees C, at which time the numbers of CFU were determined and corrected for tissue weight. To assess renal and hepatic toxicity, serum creatinine and aspartate aminotransferase levels were determined. Fungizone and ABLC at a dosing regimen of 1 mg/kg i.v. once daily for four consecutive days and Caspofungin at a dosing regimen of 3 mg/kg i.v. once daily for four consecutive days had similar effectiveness in decreasing the total number of Aspergillus fumigatus CFUs found in all organs analyzed compared to non-treated controls. A combination of ABLC (1 mg/kg i.v. x 4 days) and Caspofungin (3 mg/kg i.v. x 4 days) significantly decreased the total number of Aspergillus fumigatus CFUs found in all organs analyzed compared to Caspofungin alone and non-treated controls. ABLC at a dosing regiment of 5 mg/kg i.v. once daily for four consecutive days was more effective in decreasing the total number of Aspergillus fumigatus CFUs found in all organs analyzed compared to Fungizone or ABLC alone at 1 mg/kg and Caspofungin alone at 3 mg/kg. However, a combination of ABLC (5 mg/kg i.v. x 4 days) and Caspofungin (3 mg/kg i.v. x 4 days) was not more effective than ABLC at 5 mg/kg or the combination of ABLC at 1 mg/kg and Caspofungin 3 mg/kg in reducing the total number of Aspergillus fumigatus CFUs compared to controls. Except for non-treated infected control rats, none of the treatment groups tested displayed a greater than 50% increase in serum creatinine concentrations from baseline. In addition, only ABLC at a dosing regimen of 1 mg/kg i.v. once daily for four consecutive days displayed a greater than 50% increase in AST concentration from baseline. Taken together, these findings suggest that ABLC at 5 mg/kg once daily x 4 days appears to be the best therapeutic choice in this animal model.
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PMID:Assessing the antifungal activity and toxicity profile of amphotericin B lipid complex (ABLC; Abelcet) in combination with caspofungin in experimental systemic aspergillosis. 1512 98

Cytotoxicity and apoptosis are common problems in the isolation and storage of human hepatocytes. In vitro environments of hepatocytes during cell infusion may be critical to reducing cellular damage and enhancing cell viability. We examined the effects of donor liver histology (40-50% steatosis vs. normal), incubation time, temperature, and three solutions for infusion on banked primary human hepatocytes, by studying: trypan blue exclusion, AST release, LDH release, MTT assay, detection of DNA ladder, and a hepatocyte proliferation assay. In addition, the microstructure functions of the endoplasmic reticulum and mitochondria of the intact hepatocytes were determined by measuring correlates of UGT 1A1 and cytochrome P-450 3A (CYP3A4) activity. In general, hepatocyte viability decreased significantly within 60 min after thawing. Cells suspended in 5% dextrose lactated Ringers solution (D5LR) maintained greater cell viability. Hepatocytes from normal liver donors showed less AST and LDH enzyme leak in comparison with cells from fatty liver donors. Mild hypothermic temperature (32 degrees C) inhibited cellular damage that otherwise significantly increased at 60 min. Hepatocytes did not proliferate until 12 h from thaw, regardless of supernatant or conditions of suspension. CYP3A4 activity and a marker for UGT 1A1 activity in hepatocytes from normal donor livers were higher than those from steatotic donor livers. These findings suggest that hepatocytes suspended for infusion after isolation from normal liver donors have normal biological functions and less cellular damage/necrosis in contrast with those isolated from fatty liver donors. These damages are inhibited significantly by maintaining hepatocytes at a mild hypothermic temperature (32 degrees C). D5LR alone maintained the best cell viability for up to 60 min. Media of D5LR + adenosine and HMM were able to partially inhibit hepatocyte apoptosis in hepatocytes from steatotic livers.
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PMID:Optimization of conditions for clinical human hepatocyte infusion. 1564 38

The hepatoprotective activity of flavonol glycosides rich fraction (F-2), prepared from 70% alcohol extract of the aerial parts of V. calcarata Desf., was evaluated in a rat model with a liver injury induced by daily oral administration of CCl4 (100 mg/kg, b.w) for four weeks. Treatment of the animals with F-2 using a dose of (25 mg/kg, b.w) during the induction of hepatic damage by CCl4 significantly reduced the indices of liver injuries. The hepatoprotective effects of F-2 significantly reduced the elevated levels of the following serum enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). The antioxidant activity of F-2 markedly ameliorated the antioxidant parameters including glutathione (GSH) content, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), plasma catalase (CAT) and packed erythrocytes glucose-6-phosphate dehydrogenase (G6PDH) to be comparable with normal control levels. In addition, it normalized liver malondialdehyde (MDA) levels and creatinine concentration. Chromatographic purification of F-2 resulted in the isolation of two flavonol glycosides that rarely occur in the plant kingdom, identified as quercetin-3, 5-di-O-beta-D-diglucoside (5) and kaempferol-3, 5-di-O-beta-D-diglucoside (4) in addition to the three known compounds identified as quercetin-3-O-alpha-L-rhamnosyl- (1-->6)-beta-D-glucoside [rutin, 3], quercetin-3-O-beta-D-glucoside [isoquercitrin, 2] and kaempferol-3-O-beta-D-glucoside [astragalin, 1]. These compounds were identified based on interpretation of their physical, chemical, and spectral data. Moreover, the spectrophotometric estimation of the flavonoids content revealed that the aerial parts of the plant contain an appreciable amount of flavonoids (0.89%) calculated as rutin. The data obtained from this study revealed that the flavonol glycosides of F-2 protect the rat liver from hepatic damage induced by CCl4 through inhibition of lipid peroxidation caused by CCl4 reactive free radicals.
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PMID:Hepatoprotective effect of flavonol glycosides rich fraction from Egyptian Vicia calcarata Desf. against CCl4-induced liver damage in rats. 1611 93

One of the most remarkable achievements of in vivo NMR spectroscopy has been the detection of rapid enzyme-catalyzed exchange reactions using phosphorus-31 magnetic resonance spectroscopy-based magnetization transfer experiments. In this paper, we report, for the first time, the in vivo carbon magnetization transfer (CMT) effect and in vivo detection of the CMT effects of the alpha-ketoglutarate <--> glutamate and the oxaloacetate <--> aspartate reactions, both of which are catalyzed by aspartate aminotransferase. By saturating the carbonyl carbon of alpha-ketoglutarate at 206 ppm in alpha-chloralose anesthetized adult rat brain, the unidirectional glutamate --> alpha-ketoglutarate flux was determined to be 78 +/- 9 mumol/g/min (mean +/- SD, n = 11) following i.v. infusion of [1,6-(13)C(2)]D-glucose. Contribution from aspartate aminotransferase-catalyzed partial reactions to the observed CMT effects was emphasized. Because of the large chemical shift separation between the alpha-carbons of the amino acids and the carbonyl carbons of the corresponding cognate keto acids, the spillover of the saturation radiofrequency pulses to the alpha-carbon resonances was negligible. The results indicate that the magnetization transfer effects of aspartate aminotransferase-catalyzed reactions can be used as new biomarkers accessible to non-invasive in vivo magnetic resonance spectroscopy techniques.
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PMID:In vivo carbon-13 magnetization transfer effect. Detection of aspartate aminotransferase reaction. 1627 Mar 28


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