Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Increased serum activities of the enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) occurred in 12 out of 19 patients with idiopathic parkinsonism when they were treated with the ergot derivative lergotrile at an oral dose varying from 50 to 150 mg daily. Hepatocellular injury was confirmed by microscopic examination of liver biopsies obtained from 3 of these patients when the serum activities of ALT and AST were appreciably elevated. Light microscopy revealed features of mild acute hepatocellular injury, and electron microscopy showed proliferation of the smooth endoplasmic reticulum and apparently unique mitochondrial changes in hepatocytes. This is the first report of pathological changes in the liver associated with the therapeutic use of an ergot derivative. The presence of a potentially reactive cyanide group in the lergotrile molecule could be causally related to the observed hepatocellular injury. It is suggested that serum ALT and AST activities should be monitored carefully when the therapeutic potential of any new ergot derivative is assessed.
 ...
PMID:Hepatocellular injury with distinctive mitochondrial changes induced by lergotrile mesylate: a dopaminergic ergot derivative. 3 55

Ovarian hyperstimulation syndrome (OHSS) is a potentially fatal condition associated with the therapeutic induction of ovulation in infertility. Liver function abnormality has been previously reported in four patients, one of whom had ultrastructural abnormalities on liver biopsy. This paper describes a patient presenting with severe OHSS 16 days after ovulation had been induced. Liver function abnormality was apparent 11 days later, with a sustained rise in alkaline phosphatase and aspartate aminotransferase (AST) which lasted up to 2 months. A liver biopsy performed during the second month of her protracted hospital admission showed marked zonal fatty change (acinar zone 1) and associated inflammation, with mitochondrial crystalline inclusions and rough endoplasmic reticulum dilatation on electron microscopy. This report discusses the clinical features and possible aetiological factors.
 ...
PMID:Liver abnormality in ovarian hyperstimulation syndrome. 198 4

The present investigation examines the possibility that Cd and ethanol have a significant toxicological interaction. This examination was warranted as exposure to either chemical is known to compromise human health. Inasmuch as both chemicals affect the morphology, biochemistry, and physiology of liver, it seemed reasonable to consider liver as a possible site of interaction. Specifically, the hypothesis that ethanol alters the hepatotoxic action of Cd was evaluated. Accordingly, male rats were injected iv with hepatotoxic (3.0 mg/kg) or lethal (4.5 mg/kg) dosages of Cd, 24 hr after single-dose ethanol administration (7 g/kg, po). Cd-induced hepatotoxicity was assessed by measuring the activities of alanine aminotransferase, aspartate aminotransferase, and sorbitol dehydrogenase in serum collected 10 hr after Cd injection. Lethality was assessed by recording the number of survivors over a 7-day period. Prior exposure to ethanol substantially reduced the lethal and hepatotoxic properties of Cd. Two mechanisms were evaluated in an effort to explain ethanol-induced suppression of Cd hepatotoxicity. Ethanol pretreatment was postulated to: (1) enhance Cd excretion in bile thereby decreasing hepatic Cd content and/or (2) reduce the interaction between Cd and target sites in liver such as organelles and cytosolic high-molecular-weight (HMW) proteins. The first proposed mechanism was incorrect as the biliary excretion of Cd was nearly abolished and the concentration of Cd in whole liver increased (33%) as a result of ethanol exposure. The second proposed mechanism was a plausible explanation of ethanol-induced suppression of Cd hepatotoxicity because ethanol pretreatment decreased (approximately 60%) the content of Cd in nuclei, mitochondria, and endoplasmic reticulum, and nearly eliminated the association of Cd with cytosolic HMW proteins. Reduction in the concentration of Cd in potential target sites of intoxication was caused by a metallothionein-promoted sequestration of Cd in cytosol.
 ...
PMID:Ethanol decreases cadmium hepatotoxicity in rats: possible role of hepatic metallothionein induction. 226 92

The clinical characteristics, laboratory results, and liver biopsy findings of seven workers with toxic liver injury associated with exposure to several solvents, including substantial levels of the widely used solvent dimethylformamide, are presented. Three patients had short exposure (less than 3 months), four long exposure (greater than 1 year). Among those with brief exposure, symptoms included anorexia, abdominal pain, and disulfiram-type reaction. Aminotransferases were markedly elevated with the ratio of alanine aminotransferase to aspartate aminotransferase always greater than 1. Liver biopsy showed focal hepatocellular necrosis and microvesicular steatosis with prominence of smooth endoplasmic reticulum, complex lysosomes, and pleomorphic mitochondria with crystalline inclusions. Among workers with long exposure, symptoms were minimal and enzyme elevations modest. Biopsies showed macrovesicular steatosis, pleomorphic mitochondria without crystalloids, and prominent smooth endoplasmic reticulum, but no evidence of persisting acute injury or fibrosis. Abnormal aminotransferases in both groups may persist for months after removal from exposure, but progression to cirrhosis in continually exposed workers was not observed. We conclude that exposure of these workers to solvents, chiefly dimethylformamide, may result in two variants of toxic liver injury with subtle clinical, laboratory, and morphological features. This may be readily overlooked if occupational history and biopsy histology are not carefully evaluated.
 ...
PMID:Clinical and pathological characteristics of hepatotoxicity associated with occupational exposure to dimethylformamide. 237 79

We used electron microscopy (EM) to analyze 52 biopsy samples from 22 patients who were receiving long-term weekly oral doses of methotrexate (MTX) for the treatment of rheumatoid arthritis. Forty-eight biopsy samples were obtained after 2-6 years of continuous treatment, and 4 samples were obtained before treatment was begun. Specimens were graded for neutral fat, secondary and tertiary lysosomes, and smooth endoplasmic reticulum (SER) in hepatocytes, and for collagen in the perisinusoidal space (Disse's space). We examined the correlations between the EM findings and the light microscopic (LM) findings in the same biopsy specimens, and between the EM findings and the results of simultaneous monthly measures of aspartate transaminase, alkaline phosphatase, bilirubin, and albumin levels, as well as history of alcohol consumption before MTX treatment and monthly assessments of clinical status during the course of treatment. The presence of collagen was minimally increased in these sequential biopsy samples, whereas fat, lysosomes, and SER were decreased. The SER decrease was statistically significant. EM findings of collagen in the space of Disse did not correlate with early fibrotic changes observed with LM. Thus, after as long as 6 years of weekly oral treatment with MTX, hepatic ultrastructural changes are minimal and are not clinically significant. The use of EM for sequential biopsy studies allows the quantitation of long-term hepatic changes that may be more limited than the impression gained after LM analysis.
 ...
PMID:Electron microscopic analysis of sequential liver biopsy samples from patients with rheumatoid arthritis. Correlation with light microscopic findings. 280 23

Livers of rats between the 16th gestational and 100th postnatal day of age were subjected to quantitative biochemical and electron microscope, morphometric analyses. The amount of total mitochondrial protein per gram of liver remained at 34% of the adult level throughout the last 4 days of gestation but this was the period of rapid rise in the levels of cytochrome c oxidase, aspartate aminotransferase, and glutamate dehydrogenase in mitochondria; the nuclear fraction also acquired some glutamate dehydrogenase but lost most of it during postnatal development. During early postnatal life the amount of mitochondrial protein rose in parallel with the levels of cytochrome c oxidase and glutamate dehydrogenase but the upsurges of glutaminase and, later, of ornithine aminotransferase were accompanied by relatively little change in total mitochondrial protein. The surface area of rough endoplasmic reticulum per unit volume of hepatocyte cytoplasm (S(v) (RER)) did not change significantly throughout the period of development studied. From the 16th day of gestation to term the surface area of smooth ER (S(v) (SER)), the volume occupied by mitochondria (V(v) (MT)) and their number (N(v) (MT)) remained at 30, 66, and 45% of their adult values, respectively. V(v) (MT) and N(v) (MT) attained their maximal levels by the 2nd postnatal day and S(v) (SER) between days 2 and 12. Mitochondria of adult liver are thus smaller and contain more protein per unit volume than do those of fetal liver. After the 12th postnatal day, hepatocytes treble their size; they acquire more cytoplasm with additional enzymes but without further change in organelle concentration. The data reveal several distinct phases in the differentiation of hepatocytes. Each phase can be characterized by the extent to which the quantity and composition of various subcellular compartments evolve.
 ...
PMID:Subcellular morphometric and biochemical analysis of developing rat hepatocytes. 434 89

Two isozymes of aspartate aminotransferase have been demonstrated biochemically. One isozyme is found in the mitochondrial fraction of the cytoplasm, the other ("soluble") in the supernatant. Both isozymes can be demonstrated by the cytochemical technique of Lee and Torack, as reported in the preceding report. Aldehyde fixation rapidly inactivates both isozymes, especially the soluble one. Inactivation can be delayed by addition of ketoglutarate to the fixative. The ketoglutarate probably competes with the fixative for the active site of the enzyme, thus protecting that region of the molecule. This enables adequate tissue preservation with enough remaining enzymatic activity to be demonstrated by the precipitation of oxaloacetate as the lead salt from a medium containing alpha-ketoglutaric acid aspartic acid, and lead nitrate. Electron-opaque material was found not only in mitochondria but, as the result of substrate protection, on the plasma membranes of many cells including erythrocytes and bacteria, the limiting membrane of peroxisomes, and the transverse tubular system of striated muscle. Occasional centrioles, neurotubules, tubules in the tails of spermatozoa, the A-I band junction in myofibrils of striated muscle, and the ground substance between cisternae of endoplasmic reticulum in intestinal goblet cells also showed precipitate. In all cases, replacement of L-aspartic acid by D-aspartic acid in the medium resulted in unstained sections. The sensitivity of extramitochondrial sites to fixation, the need of ketoglutarate as an agent for protecting the enzymatic activity during the fixation process, and the known presence of only soluble isozyme in erythrocytes indicate that enzymatic activity at these sites can be attributed to the soluble isozyme. Localization of the soluble isozyme on the plasma membrane may be related to possible involvement in depolarization phenomena, amino acid transport, or synthesis of plasma membrane-bound mucopolysaccharides.
 ...
PMID:The ultrastructural localization of the isozymes of aspartate aminotransferase in murine tissues. 553 35

Feeder pigs weighing 12 to 15 kg each were given a single oral dose of aflatoxin, 1.2 mg/kg of body weight. Liver-specific serum enzyme activities were compared with gross, microscopic, and ultrastructural hepatic changes in individual pigs euthanatized at 24, 48, and 72 hours after they were given aflatoxin. The greater the morphologic change in liver of the treated pigs, the greater the increase in liver-specific serum enzyme activities. Isocitric dehydrogenase, alkaline phosphatase, sorbitol dehydrogenase, and aspartate aminotransferase activities increased in 6 of 8 treated pigs by 24 hours. Increase in gamma-glutamyl transpeptidase activity was not significant. Microscopic and ultrastructural changes in centrilobular hepatocytes included glycogen deletion, mitochondrial and endoplasmic reticulum swelling, membrane disruption, and nuclear fragmentation at 24 hours. The centrilobular areas had marked extravasation of erythrocytes at 24 hours without basal lamina changes. At 72 hours, the centrilobular hepatocytes had increased lipid vacuoles and acceptable amounts of glycogen. Marked infiltrations of monocytes, plasma cells, and lymphocytes were also present at this time.
 ...
PMID:Acute aflatoxicosis in swine: clinical pathology, histopathology, and electron microscopy. 612 94

Heroin abusers are frequently found to have abnormal liver function tests and hepatic histology. Hepatitis viruses A, B, and NANB, other drugs or drug contaminants and excessive alcohol consumption are factors thought to contribute. One hundred and sixteen heroin abusers attending a London treatment centre were studied. Sixty two (53%) had a raised aspartate transaminase. This was not explained by current infection with hepatitis A and B, cytomegalo or Epstein-Barr viruses, excessive alcohol consumption (greater than 80 g/day) or concomitant drug taking. Abnormal liver function tests were as frequent in those with markers of current or past HBV infection as those without and there was evidence that both HBV infection and the cause of the abnormal liver function tests were acquired in the first few years of intravenous drug abuse. Liver biopsies from eight patients showed chronic hepatitis with a mild lobular and portal inflammatory infiltrate, fatty change and prominent sinusoidal cells. Electron microscopy showed cytoplasmic trilaminar tubular structures and dense fused membranes in dilated endoplasmic reticulum. These clinical, biochemical, serological, and histological features would suggest a major role for NANB virus infection in the aetiology of hepatitis in heroin abusers.
 ...
PMID:Clinical, biochemical, serological, histological and ultrastructural features of liver disease in drug abusers. 642 58

Pretreatment with Zn is known to produce tolerance to several toxic effects of Cd. This study was designed to determine if zinc pretreatment decreased Cd-induced lethality and hepatotoxicity. Rats given 4.0 mg Cd/kg, iv, died within 10 to 20 hr while there was no mortality in rats pretreated with Zn (12 mg Zn/kg, sc, 48 and 24 hr prior to Cd challenge). Ten hr after Cd, plasma aspartate aminotransferase and sorbitol dehydrogenase activities were markedly elevated and extensive histopathologic lesions of the liver were evident in control rats while such injury was not evident in Zn-pretreated rats. To examine the mechanism of this tolerance, distribution of Cd to 14 organs and the subcellular distribution in 6 organs (liver, kidneys, intestines, heart, spleen, and testes) was determined in control and Zn-pretreated rats. Two hours after challenge (3.5 mg Cd/kg, iv, 7 microCi 109Cd/mg Cd), the distribution of Cd to the liver markedly increased after Zn pretreatment without concomitant decreases in other tissues. Zn pretreatment resulted in distribution of more Cd to hepatic cytosol and less associated with endoplasmic reticulum. Gel filtration chromatography indicated that most cytosolic Cd was bound to metallothionein. These data suggest that Zn pretreatment reduces Cd-induced hepatotoxicity which prevents the lethal effects of Cd possibly by altering the hepatic subcellular distribution of Cd.
 ...
PMID:Zinc-induced tolerance to cadmium hepatotoxicity. 674 Jun 79


1 2 3 4 5 6 7 8 9 Next >>