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PubMed1990

Relationship between levels of aspartate aminotransferase in gingival crevicular fluid and gingival inflammation.

Data from several sources demonstrate that disease-active and disease-inactive periodontal pockets exist, but currently available diagnostic procedures do not permit identification of disease-active sites at any given point in time. Using the experimental gingivitis model, we have performed studies aimed at determining whether levels of the enzyme aspartate aminotransferase (AST) in gingival crevicular fluid correlate with the presence and extent of periodontal inflammation. Gingival inflammation was assessed using the Gingival Index and the Sulcular Bleeding Index, and enzyme activity was measured using a standard procedure. Our data reveal a statistically significant association between AST values and Gingival Index scores for spontaneously occurring lesions (p less than 0.02-0.04) and experimentally induced lesions (p less than 0.0001), as well as the extent of change in these values during developing experimental gingivitis (p less than 0.0001) and resolving experimental gingivitis (p less than 0.0001). The data demonstrate that AST levels can be used to assess the presence and extent of periodontal inflammation.

Adolescent↗
PubMed2002

Examination of the role of abdominal computed tomography in the evaluation of victims of trauma with increased aspartate aminotransferase in the era of focused abdominal sonography for trauma.

BACKGROUND: Current evaluation of patients with negative findings on a focused abdominal sonography for trauma scan and an isolated increase of admission hepatic enzymes includes abdominal computed tomography (CT). Many of these patients do not have clinically important hepatic injuries. The purpose of this study was to establish the admission aspartate aminotransferase (AST) level below which patients do not need an abdominal CT for injury evaluation and treatment. METHODS: Patients who were hemodynamically stable, had a focused abdominal sonography for trauma scan with negative findings, and an AST level greater than 200 IU/L were identified over a 1-year period. Medical records were reviewed for demographics, injuries sustained, mechanism, evaluation, interventions, and complications. RESULTS: A total of 67 patients, mostly with blunt trauma, were identified; 42 (63%) had an AST level < 360 IU/L, and 25 (37%) had an AST level > 360 IU/L. Patients with an AST level > 360 IU/L had a 88% chance of having any hepatic injury and a 44% chance of having an injury of grade III or greater (P =.0001). Patients with an AST level of < 360 IU/L only had a 14% chance of having a liver injury and no chance of having an injury of grade III or greater (P =.036). CONCLUSIONS: Clinically important hepatic injuries are not missed if an abdominal CT is only performed for patients with a focused abdominal sonography for trauma scan with negative findings and an AST level of > 360 IU/L. Eliminating unnecessary CT allows for more cost-effective use of resources.

Abdominal Injuries↗
PubMed2006

Hyaluronic acid and aspartate aminotransferase levels normalized by liver function can reflect sinusoidal impairment in chronic liver disease.

BACKGROUND/AIM: To evaluate the relationship between hyaluronic acid/aminopyrine breath test (HA/ABT) ratio and fibrosis score in chronic hepatitis, and between HA/ABT and clinical staging (child-turcotte-pugh'score, CTP; and model for end stage liver disease, MELD) in cirrhosis, as well as to evaluate the aspartate aminotransferase (AST)/ABT in relation to the HA/ABT. METHODS: We studied 48 patients with histologically proven chronic hepatitis C (CHC) and 35 patients with compensated cirrhosis (CIR). RESULTS: HA/ABT and AST/ABT showed a more significant correlation with the fibrosis score than HA or ABT or AST alone in the 48 CHC patients: r=0.568 (P<0.0001), r=0.610 (P<0.0001), r=0.450 (P=0.0021), r=-0.449 (P=0.0021), and r=0.472(P=0.0012), respectively. Progressive liver damage (fibrosis 1-2 vs fibrosis 3-6 vs cirrhosis) was significantly (P<0.05) reflected by both HA/ABT (mean+/-SEM: 4.0+/-0.9 vs 18.1+/-4.2 vs 149.9+/-33.1) and AST/ABT (6.3+/-1.8 vs 12.7+/-1.6 vs 42.1+/-14.6). A strong relationship was found between HA/ABT and AST/ABT (r=0.755 P<0.0001). In cirrhotic patients, the most significant relationship was observed between HA/ABT and CTP r=0.483 and P=0.0049, and MELD r=0.523 and P=0.0023. CONCLUSION: Considering that HA levels in chronic hepatitis depend on the progressive impairment of sinusoidal endothelial cells (SEC), related to progressive fibrosis, HA/ABT ratio would seem to be the most specific reflection of progressive impairment of the SEC. AST/ABT could be used as a possible surrogate of HA in identifying SEC impairment in chronic hepatitis.

Adult↗
PubMed1977

[Aspartate aminotransferase activities in renal tissue during experimental and human chronic pyelonephritis].

This study belongs to a series of comparative biochemical and semiquantitative-histological investigations in renal tissue fractions of pyelonephritis patients (human PN) and of different types of experimental pyelonephritis (experimental PN). The experiments aim at more detailed knowledge on the interrelationship of intermediary cell metabolism and histopathological changes during the different phases of human and experimental PN. The results concerning acid and alkaline phosphatase activities as well as concerning glutaminase I and glutamic dehydrogenase activities were earlier reported (Exp. Path. vols. 8, 9, 10 and 12). In the present study the author has analyzed the activities of aspartate aminotransferase (E.C.2.6.1.1. AspAT) the synonym of which is glutamic oxaloacetic transaminase (GOT).

Animals↗
PubMed2003

Aspartate aminotransferase activity in gingival crevicular fluid during orthodontic treatment. A controlled short-term longitudinal study.

BACKGROUND: During orthodontic tooth movement, the early response of periodontal tissues to mechanical stress involves an acute inflammatory response, with a sequence characterized by periods of activation, resorption, reversal, and formation in both tension and compression sites. This study used a longitudinal design to examine aspartate aminotransferase (AST) activity in gingival crevicular fluid (GCF) in order to assess whether AST in GCF has potential as a possible diagnostic aid to monitor tooth movement and tissue response during orthodontic treatment. METHODS: Eighteen patients (mean age, 16.1 years) participated in the study. An upper first molar from each patient undergoing treatment for distal movement served as the test tooth (TT), with its contralateral (CC) and antagonist (AC) first molars used as controls. The CC was included in the orthodontic appliance, but was not subjected to the orthodontic force; the AC was free from any orthodontic appliance. The GCF around the experimental teeth was collected from both mesial and distal tooth sites immediately before appliance activation, 1 hour after, and weekly over the following 4 weeks. Clinical gingival condition was evaluated at baseline and at the end of the experimental period. AST activity was determined spectrophotometrically at 30 degrees C, and the results were expressed as total AST activity (mU/sample). RESULTS: Throughout the experiment, AST levels were significantly elevated in all sites from the TT and CC groups compared to the AC group where, conversely, AST activity remained at the baseline level. However, enzyme levels in the TT group were significantly greater than in the CCs at tension sites on day 14, and in compression sites on days 7 and 14. Moreover, AST activity from the TT group was significantly greater in compression sites than in tension sites on day 7; this was not observed for the CCs. CONCLUSIONS: Our results suggest that AST levels in GCF reflect the biological activity which occurs in the periodontium during controlled occlusal trauma and, therefore, should be further evaluated as a diagnostic tool for monitoring correct orthodontic tooth movement in clinical practice.

Adolescent↗
PubMed1991

Aspartate aminotransferase, malate dehydrogenase, and pyruvate carboxylase activities in rat cerebral synaptic and nonsynaptic mitochondria: effects of in vitro treatment with ammonia, hyperammonemia and hepatic encephalopathy.

The effects of in vitro treatment with ammonium chloride, hepatic encephalopathy (HE) due to thioacetamide (TAA) induced liver failure and chronic hyperammonemia produced by i.p. administration of ammonium acetate on the activity of the two malate-aspartate shuttle enzymes: aspartate aminotransferase (AAT), malate dehydrogenase (MDH), and on the pyruvate carboxylase (PC) activity were examined in synaptic and nonsynaptic mitochondria from rat brain. With regard to the shuttle enzymes the response to ammonium ions in vitro (3mM NH4Cl) was observed in nonsynaptic mitochondria only, and was manifested by a 27% decrease of AAT activity and a 16% decrease in MDH activity. By contrast, both in vivo conditions primarily affected the synaptic mitochondrial enzymes: TAA-induced HE produced a 26% decrease of synaptic mitochondrial AAT and a 50% decrease of synaptic mitochondrial MDH. Hyperammonemia inhibited synaptic mitochondrial AAT by 30% and synaptic mitochondrial MDH by 45%. HE produced no effect at all in nonsynaptic mitochondria while hyperammonemia produced a 30% increase in the AAT activity, but no changes in MDH. All the experimental conditions affected the nonsynaptic mitochondria PC: ammonium chloride in vitro produced a 20% decrease, TAA-induced HE--a 30% decrease, whereas hyperammonemia inhibited the enzyme by 53%. The PC activity in synaptic mitochondria was very low (about 2% of that measured in nonsynaptic mitochondria), which is consistent with the primarily astrocytic localization of the enzyme.

Ammonia↗
PubMed2003

2H, 13C, and 15N kinetic isotope effects on the reaction of the ammonia-rescued K258A mutant of aspartate aminotransferase.

Deuterium isotope effects at C2 of aspartate and heavy atom isotope effects at C2, C3, and the amino group of aspartate were determined for the reaction of the lysine-258 to alanine mutant of Escherichia coli rescued with exogenous ammonia. We were able to calculate an (15)N intrinsic isotope effect of 1.034. The intrinsic (13)C isotope effect at C3 is 1.0060, and the (13)C isotope effect at C2 is 1.0016. These isotope effects reveal that collapse of the carbinolamine (or gem-diamine) to give the final product is the rate-determining step in this system. Furthermore, these results indicate that lysine-258 is critical to the catalysis of the final breakdown to give product, and in fact this step is more strongly affected by mutation of lysine-258 than the deprotonation of the external aldimine.

Ammonia↗
PubMed1993

Muscle histopathology and plasma aspartate aminotransferase, creatine kinase and myoglobin changes with exercise in horses with recurrent exertional rhabdomyolysis.

Six horses with a history of recurrent exertional rhabdomyolysis (RER) (Horses A-F) and 7 control horses performed a submaximal and later a near-maximal treadmill exercise test. Blood samples were obtained before, during and after exercise and muscle biopsies were taken before and after exercise. At rest, plasma aspartate aminotransferase (AST) activities in horses with RER were above 95% confidence intervals for control horses. During submaximal exercise, 3 horses with RER (A, B and C) had much greater increases in plasma AST, creatine kinase (CK) and myoglobin concentrations than did Horses D, E and F and control horses. Clinical signs of muscle stiffness and pain were only obvious in Horse A. During near-maximal exercise, only Horse C showed a substantial increase in CK activity and myoglobin concentrations without any associated clinical signs of rhabdomyolysis. Muscle biopsies from Horses A, B and C contained necrotic type II fibres which, on electron microscopic examination, contained disrupted myofibrils and swollen mitochondria. These results suggest that, in RER, subclinical episodes of muscle fibre necrosis and associated increases in plasma AST, CK and myoglobin occur with exercise more frequently than could be detected clinically. Furthermore, the pattern of increase in muscle enzymes and myoglobin concentrations in the 6 horses with RER suggested that the high plasma AST and CK activities commonly observed at rest in symptom-free Standardbred horses are probably a result of repeated subclinical episodes of rhabdomyolysis after exercise, rather than leakage due to abnormal sarcolemmal permeability.

Animals↗
PubMed1997

In situ detection of myocardial infarction in pig by measurements of aspartate aminotransferase (ASAT) activity in the interstitial fluid.

Microdialysis probes permeable to large molecules (m.w. cut-off > 200 kD) were introduced into the myocardium of anaesthetized pigs in order to evaluate their potential for early detection of myocardial ischaemia and enzyme markers for infarction. The left anterior descending coronary artery was occluded for 30 min and the myocardium was reperfused for 3 h. The concentrations of aspartate aminotransferase (ASAT), lactate, glucose and selected free amino acids were measured. The levels in the interstitium of ischaemic and non-ischaemic myocardium were compared with those in plasma from the coronary sinus as well as from a peripheral vein. Twelve probes were inserted in six pigs and withdrawn after 8-72 hours of sampling. No complications occurred. Simultaneous 100% increase of ASAT and lactate was found in myocardial dialysates after 30 min of ischaemia. ASAT activity remained at that level until the end of reperfusion. The plasma peak ASAT level was not attained until after 3 h. Glutamate was the only amino acid which increased significantly in the myocardial interstitium during ischaemia, peaking after 30 min of reperfusion. Dialysates from the unaffected myocardium showed no effects on lactate, ASAT or glutamate. The use of myocardial microdialysis for pre- and postoperative recordings in man is discussed.

Amino Acids↗
PubMed1979

Enzymic memory. Steady state kinetic and physical studies with ascorbate oxidase and aspartate aminotransferase.

Enzymic memory is a kinetic phenomenon observable in double displacement mechanisms. The defining feature of enzymic memory is the occurrence of different rates of transfer for a common transferable group from the substituted enzymes obtained with different donor substrates. Memory behavior was previously demonstrated for both the bovine and human liver rhodaneses (EC 2.8.1.1). Steady state kinetic tests for enzymic memory have now been done with ascorbate oxidase (EC 1.10.3.3) and aspartate aminotransferase (EC 2.6.1.1). The results were positive with ascorbate oxidase, which showed an oxygen reactivity ratio of 1:20:300 for the reduced enzymes obtained with reductate, araboascorbate, and ascorbate, respectively. Results were negative for the aminotransferase tested with the alternate donors glutamate and cysteine sulfinate, with oxaloacetate as the common acceptor. The structural basis of the ascorbate oxidase results was probed by comparison of both the ultraviolet absorption and fluorescence spectra of the oxidized enzyme with those of the reduced forms obtained with ascorbate and reductate. The results are consistent with a conformational basis for the memory phenomenon.

Animals↗
PubMed2004

GFP-labelled Rubisco and aspartate aminotransferase are present in plastid stromules and traffic between plastids.

Plastid stromules are membrane-bound protrusions of the plastid envelope that contain soluble stroma. Stromules are often found connecting plastids within a cell and fluorescence recovery after photobleaching (FRAP) experiments have demonstrated that green fluorescent protein (GFP) can move between plastids via these connections. In this report, the ability of endogenous plastid proteins to travel through stromules was investigated. The motility of GFP-labelled plastid aspartate aminotransferase and the Rubisco small subunit was studied in stromules by FRAP. Both fusion proteins assemble into protein complexes that appear to behave similarly to their endogenous counterparts. In addition, both enzymes are capable of trafficking between plastids via stromules.

Arabidopsis↗
PubMed1991

Effect of pyridoxine-deficiency on degradation of cytosolic aspartate aminotransferase in rat liver lysosomes.

Highly purified lysosomes were isolated from the livers of control and pyridoxine-deficient rats. The calculation of the lysosomal protein contents indicated that the livers of both groups of rats contain virtually the same amounts of the lysosomal proteins (12.0 and 13.0 mg lysosomal proteins/g liver proteins for the control and pyridoxine-deficient rats, respectively). The immunoblotting of the lysosomal proteins with anti-cytosolic aspartate aminotransferase (cAspAT) showed 46 kDa band, corresponding to the subunit molecular weight of cAspAT, as well as the bands representing degradative intermediates of cAspAT. The relative amounts of the immuno-reactive substances were estimated by scanning the immuno-stained bands and measuring the densitometric tracings. It was found that the lysosomes in the pyridoxine-deficient rat liver contain almost twice as much cAspAT and its degradative intermediates as those in the control rat liver. On the basis of these observations, it was concluded that the increased rate of degradation of cAspAT in the liver of the pyridoxine-deficient rats is brought about by the increased rate of sequestration of cAspAT into lysosomes.

Animals↗
PubMed1975

Initial expression of the genes for fructose 1,6-diphosphatase, malic enzyme, and aspartate aminotransferase in Japanese quail and chicken--quail hybrid embryos.

The initial appearance of a number of enzymes involved in gluconeogenesis was investigated in the early embryogenesis of the Japanese quail (Coturnix coturnix japonica), the domestic chicken (Gallus gallus domesticus), and chicken-quail hybrids. Starch gel electrophoresis and enzyme-specific stains revealed genetic differences between muscle and liver fructose 1,6-diphosphatase (FDPase) as well as malic enzyme (ME) and mitochondrial aspartate aminotransferase (AAT) isozymes of the two species. ME and AAT were present in unfertilized unincubated eggs, indicating maternal storage of these enzymes. The initial expression of the paternally inherited genes in the hybrid occurred before oviposition in the case of ME, and between 12 and 18 hr incubation in the case of AAT. Initial expression of both parental sets of genes for FDPase occurred synchronously between 16 and 24 hr in the hybrid, corresponding to the time of initial appearance of this enzyme in the quail and chicken. Glucose 6-phosphate administration at 0 hr was found to cause no prevention or delay of initial enzyme activation. These results are interpreted in terms of early patterns of enzyme activation regulation and nutrition in the avian embryo.

Animals↗
PubMed1993

A developmental study of lactate dehydrogenase isozyme and aspartate aminotransferase activity in organotypic rat hippocampal slice cultures and primary cultures of mouse neocortical and cerebellar neurons.

The development of enzyme activity and isozyme distribution of lactate dehydrogenase (LDH) was studied in murine organotypic hippocampal slice cultures and dissociated cultures of neocortical neurons and cerebellar granule cells and compared with that of the respective brain regions in vivo. In the hippocampal slice cultures and the hippocampus in vivo, the activity of aspartate aminotransferase (AAT) was also measured. During development in culture the specific activity of LDH increased in all types of cultures reaching values similar to that found in the corresponding brain areas in vivo. However, significant differences in the isozyme distribution were observed between the preparations in vitro and in vivo. During development in vivo, the LDH isozyme pattern changed from a preferential M-subunit composition to a preferential H-subunit composition regardless of the brain area. This shift was not observed in the respective cultures where the M4-isozyme prevailed at all culture periods examined accounting for 30-45% of the total LDH activity. The cultured cerebellar granule cells did not express the H4-isozyme at all, while in the hippocampal slice cultures and the cultured neo-cortical neurons this isozyme accounted for about 5% of the total LDH activity. The activity of AAT in the hippocampal organotypic slice cultures increased considerably during the culture period in parallel with the increase in AAT activity during postnatal development of hippocampus in vivo. The activity of AAT in the slice cultures was, however, consistently lower than the corresponding activity in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Relationship between gingival crevicular fluid levels of aspartate aminotransferase and active tissue destruction in treated chronic periodontitis patients.

Data from several sources demonstrate that disease-active and disease-inactive periodontal pockets exist, and that disease progression occurs in bursts of activity. Currently used diagnostic procedures do not distinguish between disease-active and disease-inactive sites at any given point in time. We report the results of studies aimed at determining whether levels of the enzyme aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) are associated with disease activity as assessed by the level of gingival inflammation and probing attachment loss. 25 previously treated periodontitis patients participating in a quarterly recall maintenance program, who had experienced recurrent periodontal deterioration, served as experimental subjects. Patients were evaluated at 3-month intervals for 2 years. Values for plaque index, gingival index, and probing attachment level were recorded, and 30-second samples of gingival fluid harvested from the mesiobuccal aspect of the 4 first molars and the distal of the 4 lateral incisors. GCF volume was measured using a Periotron 6000, and AST activity was measured by a standard method. Sites were ranked in a hierarchy based on the degree of certainty of attachment loss as well as the severity of gingival inflammation, and the relationship of the values to AST levels was determined. Three models were used to analyze the resulting data, and all led to the same conclusion. Maximum enzyme level was significantly elevated at sites with confirmed disease activity as assessed by attachment loss, with maximum AST levels 725 units higher at these sites, on average, than at other sites (p less than 0.0001). Our data support the idea that an objective diagnostic test, based on levels of AST in GCF, that distinguishes between disease-active and disease-inactive sites may be possible.

Aspartate Aminotransferases↗
PubMed1979

Similarities between cysteinesulphinate transaminase and aspartate aminotransferase.

A method for the purification of two cysteinesulphinate transaminases, A and B (EC 2.6.1), is described. These enzymes catalyse the conversion of cysteinesulphinic acid to beta-sulphinyl pyruvate. The final preparations are homogeneous by polyacrylamide gel electrophoresis, sodium dodecyl sulphate-polyacrylamide gel electrophoresis and isoelectrofocusing. The molecular weight of the subunits is 41 000 for cysteinesulphinate transaminase A and 43 400 for B. Both enzymes are unspecific, as L-asparate, L-glutamate and L-cysteic acid serve as substrates in addition to L-cysteinesulphinic acid. Cysteinesulphinate transaminase A has a Km of 9.8 mM for cysteinesulphinic acid and 0.25 mM for aspartic acid, whereas the B enzyme has a Km of 6.5 mM for cysteinesulphinic acid and 1.4 mM for aspartic acid. The Vmax values of the A and B enzymes are respectively 7.1 and 6.2 mmol h-1 mg-1 protein for aspartic acid and 45 and 9.3 mmol h-1 mg-1 protein for cysteinesulphinic acid. Both enzymes exhibit maximum activity at pH 8.6. A high specific activity is found in optimal conditions for these two transaminases, the pI values being 9.06 and 5.70 for cysteinesulphinate transaminase A and B respectively. These results have been compared with those already obtained for purified aspartate aminotransferase. Similarities in the pathways of taurine and gamma-aminobutyric acid (GABA) metabolism are discussed.

Aging↗