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At least 775 records · Page 43Linked to original sources
PubMed2005

Marked elevation in serum transaminases: an atypical presentation of choledocholithiasis.

BACKGROUND: Choledocholithiasis causes elevations in levels of alkaline phosphatase out of proportion to aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Isolated marked elevation in AST and ALT levels over 1,000 IU/L has been reported infrequently in patients with choledocholithiasis. METHODS: The charts of 18 patients who presented between 1971 and 2002 with documented choledocholithiasis and AST or ALT levels greater than 1,000 IU/L were retrospectively reviewed. An extensive work-up for coexisting disease processes to account for the abnormal AST and ALT levels was negative. RESULTS: Eighteen patients (16 women, 16 Hispanics, age 38 +/- 3 yr) presented with symptoms of choledocholithiasis and marked transaminase elevation. Peak levels of AST and ALT were 1,062 +/- 129 and 1,119 +/- 90, respectively. Following successful management of gallstone disease, AST and ALT levels fell rapidly to 129 +/- 22 and 268 +/- 61, respectively, within 3-14 days. There was also a concomitant improvement in the levels of bilirubin and alkaline phosphatase. CONCLUSIONS: In the absence of other hepatobiliary or pancreatic disease, choledocholithiasis can result in elevations in AST and/or ALT greater than 1,000 IU/L. These levels fall markedly once the gallstone disease is appropriately managed.

Adult↗
PubMed1989

Use of the ferritin/alanine aspartate transaminase ratio as an iron overload marker independent of liver cell damage.

To define an iron overload index independent of liver cell damage, the mean annual levels of alanine aspartate transaminase (ALAT) and serum ferritin and their ratios were determined. Ferritin/ALAT ratio values were compared between two groups of patients with acute or chronic hepatitis without iron overload, and one group of thalassaemic patients with iron overload. The two groups without iron overload exhibited ferritin/ALAT ratio values of 2 and 1.2 respectively; a ratio value higher than 10 was always observed in those patients with iron overload. The ferritin/ALAT ratio is correlated with the degree of iron overload. This ratio increases in regularly-transfused patients without chelation treatment. It generally remains stable or decreases after initiation of iron chelation therapy. The ferritin/ALAT ratio thus appears useful in the follow-up of patients subjected to a long-term transfusional treatment particularly when acute or chronic liver cell damage may interfere with iron overload by increasing serum ferritin values.

Alanine Transaminase↗
PubMed1998

Viremia in chronic hepatitis C patients evaluated by the Amplicor RT-PCR, a nested RT-PCR, and transaminase levels.

A commercially available kit, Amplicor, was compared with a locally developed nested reverse-transcriptase (RT) PCR for qualitative detection of HCV-RNA. Sixty-one serum samples from sixty-one patients with liver disease, and 60 samples from 60 hemophiliacs without symptoms, but known to have been heavily exposed to hepatitis C virus, were investigated. There was a high degree of concordance between the two diagnostic tests (97%), the Amplicor kit being slightly more sensitive than the in-house PCR, when evaluated using serial dilutions of samples showing discrepant results. The relationship between viremia and abnormal ALT levels was studied in the two groups of patients. Among those with chronic liver disease, 8.3% of patients with viremia had normal ALT levels, whereas transaminases were normal in 20% of hemophiliacs with viremia. This points to ALT as being a poor marker of ongoing viral replication.

Adolescent↗
PubMed1967

Failure of cycloheximide to induce tyrosine transaminase in the anesthetized rat.

It was recently reported that cycloheximide, an inhibitor of protein synthesis, induces tyrosine transaminase in the liver of adrenalectomized rats. We have been unable to confirm this effect in the anesthetized animal and our data show that cycloheximide inhibits the induction caused by hydrocortisone in adrenalectomized rats or by stress in intact rats.

Adrenalectomy↗
PubMed1968

Tyrosine-alpha-ketoglutarate transaminase: induction by epinephrine and adenosine-3',5'-cyclic phosphate.

Epinephrine and the N6-O2'-dibutyryl analog of adenosine-3', 5'-cyclic phosphate both are effective inducers of tyrosine-alpha-ketoglutarate transaminase in explants of fetal rat liver maintained in organ culture. Combinations of these inducers with each other and with hydrocortisone, another inducer, yielded results which suggest that cyclic adenylic acid is an intermediate in the induction by epinephrine and that the mechanism by which it induces is different from that by which hydrocortisone operates.

Adenine Nucleotides↗
PubMed1968

Tyrosine transaminase: development of daily rhythm in liver of neonatal rat.

The development of the 24-hour rhythm in tyrosine transaminase activity was studied in the liver of the neonatal rat. A recognizable rhythm appears within 48 hours after birth, but it is opposite in phase to that observed in the adult rat. The reversal of the adult pattern occurs 21 to 23 days after birth and may represent a response to a change both in the eating pattern and in the amount of protein eaten.

Animals↗
PubMed2005

Use of enrichment culture for directed evolution of the Vibrio fluvialis JS17 omega-transaminase, which is resistant to product inhibition by aliphatic ketones.

A novel high-throughput screening method that overcame product inhibition was used to isolate a mutant omega-transaminase from Vibrio fluvialis JS17. An enzyme library was generated using error-prone PCR mutagenesis and then enriched on minimal medium containing 2-aminoheptane as the sole nitrogen source and 2-butanone as an inhibitory ketone. An identified mutant enzyme, omega-TAmla, showed significantly reduced product inhibition by aliphatic ketone. The product inhibition constants of the mutant with 2-butanone and 2-heptanone were 6- and 4.5-fold higher than those of the wild type, respectively. Using omega-TAmla (50 U/ml) overexpressed in Escherichia coli BL21, 150 mM 2-aminoheptane was successfully resolved to (R)-2-aminoheptane (enantiomeric excess, >99%) with 53% conversion with an enantioselectivity of >100.

Amines↗
PubMed1971

Phenylalanine and tyrosine biosynthesis in Escherichia coli K-12: mutants derepressed for 3-deoxy-D-arabinoheptulosonic acid 7-phosphate synthetase (phe), 3-deoxy-D-arabinoheptulosonic acid 7-phosphate synthetase (tyr), chorismate mutase T-prephenate dehydrogenase, and transaminase A.

Mutant strains of Escherichia coli have been isolated in which the synthesis of 3-deoxy-d-arabinoheptulosonic acid 7-phosphate (DAHP) synthetase (phe) is derepressed, in addition to those enzymes of tyrosine biosynthesis previously shown to be controlled by the gene tyrR. The major enzyme of the terminal pathway of phenylalanine biosynthesis chorismate mutase-prephenate dehydratase is not derepressed in these strains. Genetic analysis of the mutants shows that the mutation or mutations causing derepression map close to previously reported tyrR mutations. A study of one of the mutations has shown it to be recessive to the wild-type allele in a diploid strain. It is proposed that the tyrR gene product is involved in the regulation of the synthesis of DAHP synthetase (phe) as well as the synthesis of DAHP synthetase (tyr), chorismate mutase-prephenate dehydrogenase, and transaminase A.

Aldehyde-Lyases↗
PubMed1973

Close linkage of the genes serC (for phosphohydroxy pyruvate transaminase) and serS (for seryl-transfer ribonucleic acid synthetase) in Escherichia coli K-12.

Escherichia coli strain K28, isolated after nitrosoguanidine mutagenesis, was found to be auxotrophic for serine. It was also temperature sensitive for growth as a result of producing an altered seryl-transfer ribonucleic acid (tRNA) synthetase (EC 6.1.1.11, l-serine: tRNA ligase [AMP]). The auxotrophy was caused by a mutation in the structural gene for phosphohydroxy-pyruvate transaminase (serC), which was distinct from, but closely linked to, the structural gene for seryl-tRNA synthetase (serS). We conclude that the relevant genes are in the order gal-serS-serC-aroA.

Amino Acyl-tRNA Synthetases↗
PubMed2003

Effect of tumour necrosis factor alpha antagonists on serum transaminases and viraemia in patients with rheumatoid arthritis and chronic hepatitis C infection.

BACKGROUND: Tumour necrosis factor alpha (TNF alpha) antagonists are effective for the treatment of rheumatoid arthritis (RA), but concerns remain about the safety of these agents in the presence of chronic infections, including hepatitis C virus (HCV) infection. OBJECTIVE: To examine the influence of treatment with TNF alpha antagonists on levels of HCV viraemia and serum transaminases in patients with RA and HCV. METHODS: In a retrospective survey the course of 16 HCV infected patients with RA who had received the TNF alpha antagonists etanercept or infliximab was analysed. Eight additional patients with RA and HCV were also enrolled into a three month prospective trial of etanercept. Serum concentrations of albumin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and HCV were followed. RESULTS: Viraemia was measured in 22 patients receiving a TNF alpha antagonist at the start of treatment and after 1-34 months (median 9 months follow up). Twenty four patients had serial tests of liver related enzymes and albumin. None of the differences between liver related tests at baseline and at follow up achieved significance (p>0.05). Similarly, the mean HCV measurement at 1-3, 4-6, 7-12, and 13-34 months did not differ significantly from baseline (p>0.05). CONCLUSION: In this study, liver related blood tests and HCV viral load measurements did not change substantially. These findings suggest that TNF alpha antagonists merit further study for the treatment of RA in HCV infected patients. Larger and longer term studies are still needed.

Adult↗
PubMed1973

Comparison of two-point (AutoAnalyzer II) with kinetic methods for transaminase assay.

The general performance of the Technicon AutoAnalyzer II method for the routine estimation of serum aspartate and alanine transaminase has been assessed and compared with that of the LKB reaction rate analyser. The results of the two methods correlate, there is little difference in precision, and running costs are comparable. Some of the relative advantages of the two types of analysis are discussed.

Alanine Transaminase↗
PubMed1990

Serum alanine transaminase (ALT) reference ranges estimated from blood donors.

It has been suggested that an increase in serum alanine transaminase (ALT) activity in blood donors may identify infection with non-A, non-B hepatitis. To facilitate identification of such donors, the reference range for ALT was measured on a Technicon SMAC 1 Analyser, using serum from 364 blood donors and 567 plasmapheresis donors. The distribution of ALT activities displayed a positive skewness, and so both logarithmic transformation and subsequent calculation of mean and standard deviation as well as non-parametric analysis were used to obtain best estimates of reference ranges for men and women, 5-65 IU/1 and 5-35 IU/1, respectively. ALT activities were found to be higher in plasmapheresis donors than in normal blood donors of both sexes, and it is postulated that this difference may be related to the increased frequency of donation in the former group.

Alanine Transaminase↗
PubMed1979

Bromine in blood, EEG and transaminases in methyl bromide workers.

In 33 methyl bromide users, slight electroencephalographic changes (in 10 subjects) and a small increase in serum transaminases were found which could be related to bromine concentration in blood. No relationship was found with subjective symptoms, general neurological examination or the results of serum protein electrophoresis.

Adult↗
PubMed1975

Glutamic-pyruvic transaminase activity related to red blood cell age.

Red blood cell glutamic-pyruvic transaminase (GPT) phenotypes and catalytic activities were studied in normal subjects and in patients with various hemolytic syndromes associated with reticulocytosis. To assess the effect of cell age of GPT activity, young cells were separated from older cells by centrifugation, and the catalytic activities were compared. In normal blood, there was a progressive fall in GPT activity from the top layer (younger cells) to the bottom layer (older cells), with a mean ratio of 1.90 plus or minus 0.42. Similarly, in the blood of patients with reticulocytosis, the enzyme activity of the reticulocyte-rich layer was higher than that of the layer containing older cells (mean ratio 1.94 plus or minus 0.95).

Alanine Transaminase↗
PubMed1979

alpha-Ketoisocaproate stimulates branched-chain amino acid transaminase in kidney and muscle.

We have reported that branched-chain amino acid transaminase (BATase) activity of isolated rat kidney is stimulated by perfusion with alpha-ketoisocaproate (KL). This study examines the mechanism of this effect in kidney and documents that stimulation occurs in intact skeletal muscle. Increased activity was not attributable to synthesis of enzyme because it occurred in the presence of cycloheximide. The in vivo degradation rate of BATase estimated from sequential measurements of activity following intravenous cycloheximide was longer than 90 min, whereas during in vitro perfusion stimulation could be detected within 5 min. Incubation of supernatant from kidney homogenate with KL stimulated BATase; incubation with alpha-keto-beta-methylvalerate (KI), alpha-ketoisovalerate (KV), leucine (leu), or isovaleryl CoA did not. Perfusion of rat hindquarter with KL increased muscle BATase activity; perfusion with acetoacetate, KI, KV, or leu did not. Again, cycloheximide studies indicated a direct effect of KL on muscle BATase. These findings suggest that alpha-ketoisocaproate can increase BATase activity and thus may be involved in regulation of its activity.

Amino Acids, Branched-Chain↗