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At least 613 records · Page 34Linked to original sources
PubMed1999

Clinical features of hepatitis C-infected patients with persistently normal alanine transaminase levels in the Southwestern United States.

Approximately one third of patients with chronic hepatitis C virus (HCV) infection have normal alanine transaminase (ALT) levels. We studied the clinical, biochemical, virological, and histological features in patients with persistently normal ALT. A case-control study was conducted on 275 patients with chronic HCV infection, including 75 patients with persistently normal ALT and 200 patients with abnormal ALT. Persistently normal ALT was defined as 4 consecutive ALT values in each patient within a period of 12 months. The average age of the patients was 44 years (range 18 to 69 years). More non-Hispanic whites had persistently normal ALT. The mean serum ferritin level was significantly lower in patients with persistently normal ALT as compared with abnormal ALT (128 +/- 92 ng/mL and 224 +/- 128 ng/mL), respectively (P =.017). The mean HCV-RNA level was significantly lower in patients with persistently normal ALT as compared with abnormal ALT (12 x 10(5) +/- 2.8 x 10(6) copies/mL and 33 x 10(5) +/- 8.0 x 10(6)), respectively (P =.02). Histologically, patients with persistently normal ALT had less severe portal inflammation (P <.05), lobular inflammation (P =.003), piecemeal necrosis (P =.002), fibrosis (P <.05), lower prevalence of cirrhosis (P =.007), as well as a slower fibrosis progression rate (P <.001). Chronic hepatitis C patients with persistently normal ALT have low-activity grade and stage on liver biopsy. In these patients the hepatitis C RNA level was lower compared with abnormal ALT patients, which may explain the slower fibrosis progression rate.

Adult↗
PubMed1984

Transaminase inhibitors block glycolysis and G1 to S phase progression in chick embryo fibroblasts: reversal by alpha-keto acids.

Two transaminase inhibitors, aminooxyacetate and cycloserine, inhibited the initiation of insulin-stimulated DNA synthesis in chick embryo fibroblasts. This inhibition was overcome when pyruvate (4 mM), oxaloacetate (4 mM), or alpha-ketobutyrate (10 mM) was included in the culture medium with hormone and inhibitor. Aminooxyacetate also inhibited lactate production in insulin-treated cultures in the absence of added alpha-keto acid.

Acetates↗
PubMed1994

Factors associated with viremia and elevated transaminase levels in asymptomatic hepatitis D virus-infected risk groups.

To detect hepatitis D virus (HDV) RNA in asymptomatic HDV-infected risk groups, Northern blot hybridization was carried out using a strand-specific riboprobe. Univariate and multivariate analyses were carried out to evaluate factors associated with HDV viremia and elevated transaminase levels in these subjects. Two (15%) of 13 antibody to HDV (anti-HDV) -positive intravenous drug addicts, 15 (33%) of 45 anti-HDV positive prostitutes, and 6 (40%) of 15 anti-HDV positive brothel goers had detectable serum HDV RNA. Older age (> 31 years old) was negatively associated with HDV RNA (P < .04), while hepatitis B e antigen (HBeAg) was positively associated with it (P < .002) in univariate analysis. Only HBeAg was still significant in multivariate analysis (P < .05). Of the 76 asymptomatic anti-HDV positive case, 28 (37%) had mildly elevated serum ALT levels and only 5 (7%) had ALT levels more than twice normal (> 80 U/L). HBeAg (P < .05) and HDV RNA (P < .02) were two factors associated with ALT elevation in univariate analysis, and HDV RNA was the only significant factor in multivariate analysis (P < .005). In summary, active replication of HBV seemed to be of help for the assembly of HDV and viremia. However, active replication of HDV was associated mostly with mildly elevated ALT levels in these subjects. These cases may represent a particular group in the disease spectrum of HDV infection.

Adolescent↗
PubMed2006

Alanine transaminase levels in the year before pregnancy predict the risk of hepatitis C virus vertical transmission.

Vertical transmission is the most common route of hepatitis C virus (HCV) infection in children. Transmission risk factors have been described, but most risk factors can only be evaluated using expensive laboratory exams. The aim of the present study was to evaluate whether maternal alanine transaminase (ALT) levels before pregnancy correlate with HCV vertical transmission. Seventy-four transmitting and 403 nontransmitting mothers were evaluated. All mothers enrolled had two ALT determinations in the last year before pregnancy, at least 6 months apart. Mothers were divided into two groups: mothers with persistently normal serum ALT levels and mothers with abnormal ALT levels. In the second group both mothers with constantly raised or with fluctuating ALT levels (one normal and one raised determination) were included. ALT was defined as raised if higher than twice the upper limit of normal. Abnormal ALT levels were found in 39/74 (52.7%) HCV transmitting mothers and in 146/403 (32.6%) nontransmitting mothers (P = 0.008; relative risk 1.96; 95% confidence limits 1.19-3.23). The risk of transmission from mothers with constantly raised ALT levels was more evident than that from mothers with fluctuating ALT levels. Increased ALT levels may reflect a more severe liver disease and a higher viral load, factors known to be associated with vertical transmission. ALT determination, a simple, widely available and inexpensive test, may help in identifying mothers with an increased risk of HCV vertical transmission.

Alanine Transaminase↗
PubMed1994

Measurement of GABA following GABA-transaminase inhibition by gabaculine: a 1H and 31P NMR spectroscopic study of rat brain in vivo.

A selective 1H NMR spin-echo editing method was used to detect the 4-CH2 of GABA in rat brain in vivo before and after intravenous administration of the highly selective GABA transaminase inhibitor, gabaculine (3-amino-2,3-dihydrobenzoic acid-HCl; 100 mg/kg, intravenously). The effects of the inhibitor on high energy phosphates and pHi were determined by 31P NMR. GABA levels increased approximately linearly (r = 0.81 to 0.94; P < 0.0005) from 1.9 +/- 0.4 mumol/g (pre-gabaculine; mean +/- SD) to between 6 and 8 mumol/g after 4 hr at rates of accumulation of 1.1 to 2.9 mumol/hr/g. 1H NMR spectroscopic measurements of cerebral GABA and its rate of turnover offers a new approach in the study of GABA-mediated processes in vivo.

4-Aminobutyrate Transaminase↗
PubMed2005

In vitro GABA-transaminase inhibitory compounds from the root of Angelica dahurica.

The 80% aqueous MeOH extracts from the root of Angelica dahurica, found to inhibit the activities of GABA degradative enzymes GABA transaminase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH), were fractionated using EtOAc, n-BuOH and H2O. Repeated column chromatography for the EtOAc and n-BuOH fractions led to the isolation of two new coumarins, oxypeucedanin hydrate-3''-butyl ether and isopraeroside IV along with six known coumarins, isoimperatorin, imperatorin, phellopterin, oxypeucedanin hydrate, nodakenin and 3'-hydroxymarmesinin, and two polyacetylenes, falcarindiol and octadeca-1,9-dien-4,6-diyn-3,8,18-triol. Of the isolated pure compounds, imperatorin and falcarindiol inactivated the GABA-T activities in both time- and concentration-dependent manners. The kinetic studies showed that imperatorin and falcarindiol reacted with the GABA-T with a second-order rate constant of 2.3 +/- 0.2 mm(-1) min(-1) and 1.5 +/- 0.1 mm(-1) min(-1), respectively. It is postulated that imperatorin and falcarindiol are able to elevate the neurotransmitter GABA levels in the central nervous system by an inhibitory action on the GABA degradative enzyme GABA-T.

4-Aminobutyrate Transaminase↗
PubMed2002

Gamma-vinyl GABA, an irreversible inhibitor of GABA transaminase, alters the acquisition and expression of cocaine-induced sensitization in male rats.

We examined the effect of (+/-)-gamma-vinyl GABA (GVG, Vigabatrin), an irreversible inhibitor of the enzyme GABA transaminase, on the acquisition and expression of cocaine-induced sensitization in albino male Sprague-Dawley rats. Animals received a single injection of 1 ml/kg i.p. of 0.9% saline or 15 mg/kg i.p. of (-)-cocaine and locomotor activity was assessed using automated locomotor cages and stereotyped behaviors were scored using a 4-point rating scale (Day 1). Subsequently, animals were given 15 mg/kg i.p. of cocaine every 48 h in their home cage for 1 week (Days 3, 5, and 7) and then given no treatment for 1 week. A challenge injection of 15 mg/kg i.p. of cocaine, but not vehicle, produced a significant increase in locomotor activity and stereotyped behaviors on Day 15 compared to animals that received cocaine on Day 1. Administration of 75 mg/kg i.p. of GVG 2.5 h before the cocaine injections did not significantly alter the acquisition of cocaine-induced locomotor sensitization. However, 150 mg/kg i.p. of GVG significantly attenuated the acquisition of cocaine-induced locomotor sensitization. Administration of 150 mg/kg i.p. of GVG 2.5 h before the cocaine challenge injection on Day 15 significantly attenuated the expression of cocaine-induced locomotor sensitization. Acquisition and expression of cocaine-induced sensitization of stereotypy was also significantly attenuated by 150 mg/kg i.p. of GVG. Since sensitization may be one of the factors involved in relapse to drug use, the present results, in combination with previous findings that GVG blocks the rewarding and incentive motivating effects of cocaine, suggest that GVG might prove useful in the treatment of cocaine addiction.

4-Aminobutyrate Transaminase↗
PubMed1998

Identification of a familial mutation associated with GABA-transaminase deficiency disease.

GABA-transaminase (GABA-T) deficiency disease is a rare recessive disorder characterized by abnormal development, seizures, and high levels of GABA in serum and cerebrospinal fluid. Although some patients are the offspring of consanguineous marriages, most are not. To identify the molecular basis of this disease, we have determined the sequence of human GABA-T cDNA. We have compared the GABA-T cDNA sequences in cultured cells derived from six healthy controls with those from a GABA-T-deficient patient and both parents. Our data indicate that GABA-T deficiency disease may result from an allele that encodes an R220K substitution.

4-Aminobutyrate Transaminase↗
PubMed1994

A rapid, high-yield purification of L-alanine:4,5-dioxovalerate transaminase from rat kidney mitochondria using an improved enzyme assay method.

The present report documents an improved enzyme assay method for the mammalian L-alanine:4,5-dioxovalerate transaminase which is of significant utility in work with crude tissue homogenates, cell cultures, or purified enzyme preparations. We also describe a new and rapid purification procedure for this enzyme from rat kidney mitochondria. The three-step procedure involves the use of digitonin and lubrol for mitochondrial matrix preparation and L-alanine-Sepharose 4B column chromatography followed by gel filtration on Sepharose 6B. By this procedure it is possible to obtain a highly purified enzyme preparation in a relatively short time with a 37.5% yield.

Animals↗
PubMed1996

Nitrogen metabolism in actinorhizal nodules of Alnus glutinosa: expression of glutamine synthetase and acetylornithine transaminase.

Two nodule cDNA clones representing genes involved in Alnus glutinosa nitrogen metabolism were analysed. ag11 encoded glutamine synthetase (GS), the enzyme responsible for ammonium assimilation, while ag118 encoded acetylornithine transaminase (AOTA), an enzyme involved in the biosynthesis of citrulline, the nitrogen transport form in Alnus. GS mRNA was found at highest levels in root nodules, where it was present in the infected cells as well as in the cells of the pericycle of the vascular system. AOTA transcripts were found at high levels in nodules, confined to the infected cells, suggesting that in nodules of A. glutinosa, citrulline biosynthesis takes place mainly in the infected cells.

Actinomycetales↗
PubMed1988

Abundant GABAergic innervation of rat posterior pituitary revealed by inhibition of GABA-transaminase.

An antibody against gamma-aminobutyric acid (GABA) was used to identify GABAergic elements immunocytochemically in the rat posterior pituitary. In order to increase the intracellular concentration of GABA, rats were treated with the GABA-transaminase inhibitor gamma-vinyl-GABA (GVG). Light-microscopic observations of Vibratome and semithin sections revealed the presence of numerous immunoreactive nerve fibers throughout the neural lobe; the mean number and length of these fibers increased by 90% after GVG treatment. Electron microscopy demonstrated the immunostained axons to be of small diameter. The reaction product was confined to small vesicles. No immunostaining occurred in pituicytes. The richness of the GABAergic innervation of the neural lobe contrasts with previous reports using antibodies against glutamate decarboxylase and supports the idea that GABA participates in the presynaptic control of neurosecretion.

4-Aminobutyrate Transaminase↗
PubMed1990

Microphotometric determination of enzymes in brain sections. II. GABA transaminase.

The tetrazolium salt procedure of van Gelder (1965) for the demonstration of GABA transaminase (GABAT; the most important GABA degrading enzyme) was adapted for microphotometric measurements of GABAT activities in brain sections using the hippocampus of rats as selected brain region. The final incubation medium consisted of 50 mM GABA, 5 mM alpha-ketoglutarate, 7 mM NAD, 10 mM sodium azide, 6 mM nitroblue tetrazolium chloride, 20 mM malonate and 15% polyvinyl alcohol in 0.05 M Hepes buffer; the final pH was 8.0. There was a linear relationship between GABAT activity and section thickness up to 14 microns and between GABAT activity and reaction time at least up to 20 min (kinetic and end-point measurements). Phenazine methosulfate as an exogenous electron carrier and pyridoxal-5-phosphate as coenzyme of GABAT did not enhance the demonstrable GABAT activities, whereas sodium azide as a blocker of the respiratory chain resulted in an increase of demonstrable enzyme activities. A coreaction of succinate dehydrogenase was excluded by the use of malonate (competitive inhibitor). Using the incubation medium described GABAT activities were demonstrated via the endogenous enzymes succinic semialdehyde dehydrogenase and NADH tetrazolium reductase which were shown to be not rate limiting and seems to be similarly localized as GABAT.

4-Aminobutyrate Transaminase↗
PubMed1975

Red cell glutamic-pyruvic transaminase gene frequencies in the region of the Po Delta (Ferrara, northern Italy).

The red cell glutamic-pyruvic transaminase phenotype has been determined in 294 individuals from the region of the Po delta (Ferrera, northern Italy). No correlation with past malarial morbidity has been detected. The gene frequencies found in this survey are similar to those reported for other Caucasian populations. One GPT3/GPT1 individual has been found.

Alanine Transaminase↗
PubMed1975

Phenotypic distributions of red cell glutamate-pyruvate transaminase (E.C.2.6.1.2) isoenzymes in British and New York populations.

1444 persons of British nationality living in London, and 294 Caucasians, 258 Negroes, 310 Hispanic persons, and 151 Chinese persons living in New York were tested for glutamate-pyruvate transaminase phenotype. The Gpt1 frequency in the British population was found to be 0.5277, the Gpt2 frequency was 0.4716, and two GPT 3-2 persons were found. The Gpt1 frequencies in the New York population were: 0.4834 in Chinese; 0.5226 in Hispanic persons; 0.8101 in Negroes; and 0.5306 in Caucasians. Two Caucasians possessed the GPT 3-2 phenotype.

Alanine Transaminase↗
PubMed1976

Glutamic pyruvic transaminase and esterase D types in the Asian-Pacific area.

More than 11000 blood samples have been examined for glutamicpyruvic transaminase (GPT) and almost 9000 for Esterase D(EsD) in the Asian-Pacific area; GPT3 and GPT6 were detected in several population groups in New Guinea, Singapore and some Pacific islands. No previously undescribed alleles were found in either system.

Alanine Transaminase↗
PubMed1977

Studies on glutamic-oxalacetic (GOT) and glutamic-pyruvic (GPT) transaminases of swine kidney worm Stephanurus dentatus (Diesing, 1839). I. Assay and general properties.

Biochemical studies on the two transaminases GOT and GPT of swine kidney worm Stephanurus dentatus have been made. GOT has been found much more active than GPT. Enzyme activities are based on the formation of oxaloacetate (GOT) or pyruvate (GPT) from aspartic acid and alanine respectively with oxoglutarate. A linear relationship is observed between the enzyme concentration and activity. GOT shows a maximum activity at pH 8.0 and Michaelis constant 9 X 10(-3) M for male and 2.9 X 10(-3) M for female. GPT has an optimum pH of 7.5 and a Michaelis constant 19 X 10(-3) M for male and 8 X 10(-3) M for female. The optimum temperature for both GOT and GPT was 60 degrees C.

Alanine Transaminase↗
PubMed1980

Genetic and biochemical studies on glutamate-pyruvate transaminase from Drosophila melanogaster.

We have used electrophoretic variants of glutamate-pyruvate transaminase (GPT, E.C., 2.6.1.2) in Drosophila melanogaster to genetically map the structural gene to position 42.6 on the X chromosome. By pseudodominance tests over several deficiencies we have localized it cytogenetically to the interval 11Fl-2 to 12Al-2. The sedimentation constant (s20,w) of the native enzyme was determined in sucrose density gradients to be 5.9 and the native molecular weight approximately 87,000. The similarity in physical properties to mammalian enzymes suggests that the enzyme may also be dimeric in D. melanogaster.

Alanine Transaminase↗