Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The possibility of assessing the relationship of ultrasound (US)-detected abdominal lymphadenopathy with etiology, biochemical findings, and histologic data in patients with chronic liver disease was evaluated. US examination of the upper abdomen was performed in 321 consecutive patients with various chronic liver disorders and 56 control patients. The prevalence of lymphadenopathy in chronic liver disease was 38%. This prevalence varied according to etiology of liver disease, from 50% in chronic hepatitis C virus (HCV) to less than 10% in alcoholic cirrhosis and hepatitis B-virus (HBV)-related chronic liver disease. Patients with lymphadenopathy showed significantly higher serum levels of AST and ALT, as well as greater histopathological severity on liver biopsy specimens. In anti-HCV positive patients, there were no differences in the prevalence of lymphadenopathy according to HCV genotypes, whereas lymphadenopathy occurred less frequently in responders to interferon therapy than in nonresponders.
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PMID:Clinical significance of abdominal lymphadenopathy in chronic liver disease. 1197 9

Persistent elevation of aspartate aminotransferase (AST) activity in serum due to the presence of a macroenzyme form of AST (macro-AST) may lead to diagnostic confusion in many clinical conditions, particularly those associated with chronic liver disease. We describe a case of macro-AST arising in an adult female with a false-positive hepatitis C virus (HCV) RNA test result that was not accompanied by other biochemical or histologic evidence of liver disease. The presence of macro-AST in serum was confirmed utilizing size-exclusion, high performance liquid chromatography (HPLC) and Protein G-agarose beads to precipitate immune complexes of AST and immunoglobulin G followed by centrifugation and AST activity measurements in the supernatant. A brief review of the clinical enzymology of AST and methods used to quantify serum macro-AST activity is provided.
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PMID:Macro-aspartate aminotransferase in a female with antibodies to hepatitis C virus. 1244 76

Chronic liver disease is a major cause of morbidity and mortality in the United States. Although often used to detect liver disease, the prevalence and etiology of elevated aminotransferases are unknown. We analyzed data on adults ages 17 yr and older (N = 15,676) from the Third National Health and Nutrition Examination Survey (1988-1994). Participants were classified as having elevated aminotransferase levels if either aspartate aminotransferase or alanine aminotransferase was elevated above normal. Aminotransferase elevation was classified as "explained" if there was laboratory evidence of hepatitis B or C infection, iron overload, or if there was a history of alcohol consumption. Analyses were weighted to provide national estimates. The prevalence of aminotransferase elevation in the United States was 7.9%. Aminotransferase elevation was more common in men compared to women (9.3% vs 6.6%, p = 0.002), in Mexican Americans (14.9%) and non-Hispanic blacks (8.1%) compared to non-Hispanic whites (7.1%, p < 0.001). High alcohol consumption, hepatitis B or C infection and high transferrin saturation were found in only 31.0% of cases. Aminotransferase elevation was unexplained in the majority (69.0%). In both men and women, unexplained aminotransferase elevation was significantly associated with higher body mass index, waist circumference, triglycerides, fasting insulin, and lower HDL; and with type 2 diabetes and hypertension in women (all p < 0.05). Aminotransferase elevation was common in the United States, and the majority could not be unexplained by alcohol consumption, viral hepatitis or hemochromatosis. Unexplained aminotransferase elevation was strongly associated with adiposity and other features of the metabolic syndrome, and thus may represent nonalcoholic fatty liver disease.
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PMID:The prevalence and etiology of elevated aminotransferase levels in the United States. 1280 14

Hepatitis C virus (HCV) infection is a common cause of liver disease in thalassemia major patients in Western, especially Mediterranean, countries. Its significance in thalassemic patients from Southeast Asia has not been critically evaluated. In this report, we describe our study of the prevalence of HCV infection among Thai patients with thalassemia. The relationships of the infection to blood transfusion and the infection's effects on liver function have also been determined. Of the 104 patients studied, 21 (20.2%) tested positively by enzyme immunoassay for anti-HCV antibody, whereas only 2 patients (2%) had the hepatitis B surface antigen. There was no significant relationship between the presence of anti-HCV antibodies and the number and frequency of blood transfusions. In fact, 2 patients (10%) who tested positive for anti-HCV antibodies had never received transfusions. Patients with anti-HCV antibodies had significantly abnormal liver functions, such as higher levels of serum aspartate aminotransferase (SGOT) and alanine aminotransferase (SGPT) and lower levels of serum albumin, compared with patients without anti-HCV antibodies (P = .021, .017, and .004, respectively). However, there were also significant correlations between iron status as indicated by transferrin saturation or serum ferritin levels and SGOT, SGPT, and gamma-glutamyltransferase (GGT) levels. Moreover, abnormal liver function as represented by elevated levels of SGOT, SGPT, GGT, and serum alkaline phosphatase was observed more frequently in patients with iron overload than in patients with a lower degree of iron burden. The presence of HCV did not alter the effects of iron overload on liver function. The findings suggest that both HCV and iron overload are the main causes of abnormal liver function in Thai patients with thalassemia. The treatment of both problems, if coexisting in patients with thalassemia, is required to prevent progression to chronic liver disease.
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PMID:Prevalence and clinical significance of hepatitis C virus infection in Thai patients with thalassemia. 1468 98

Ten percent of patients who undergo resection for hepatocellular carcinoma (HCC) associated with chronic liver disease have no detectable cause for this underlying liver disease. Recent studies have shown that patients with cryptogenic chronic liver disease frequently have risk factors for nonalcoholic fatty liver disease (NAFLD). This study examines the incidence of risk factors for NAFLD in patients with chronic liver disease who underwent resection for HCC. Among 210 patients with chronic liver disease who underwent resection for HCC, 18 (8.6%) had no identifiable cause for the underlying liver disease. These patients were assessed for obesity, diabetes mellitus, and histological features of the tumor and the adjacent liver parenchyma. Comparisons were made with matched patients with alcohol- and chronic-viral-hepatitis-related HCC. The prevalence of obesity (50% vs. 17% vs. 14%), diabetes (56% vs. 17% vs. 11%), aspartate aminotransferase/alanine aminotransferase ratio<1 (50% vs. 19% vs. 17%), and steatosis>20% (61% vs. 17% vs. 19%) was significantly higher in patients with cryptogenic liver disease than in patients with alcohol abuse and chronic viral hepatitis (P<0.0001 for each). Well-differentiated tumors were significantly more common in patients with cryptogenic liver disease (89% vs. 64% in patients with alcohol-related HCC vs. 55% in patients with chronic viral hepatitis-related HCC, P<0.0001). In conclusion, the hypothesis that obesity and diabetes mellitus may be important risk factors for cryptogenic chronic liver disease in patients with HCC is supported by the analysis of surgically treated patients. Whether HCC is primarily related to obesity and diabetes mellitus or secondarily to a NAFLD-like parenchymal lesions remains to be clarified.
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PMID:Obesity and diabetes as a risk factor for hepatocellular carcinoma. 1476 43

HIV caregivers face many challenges following initiation of ART. The development of jaundice is uncommon but worrisome. In this case, two distinct and contrasting episodes of jaundice were observed. In the first instance, isolated elevation of the indirect bilirubin without elevation of the alkaline phosphatase was noted. The normal PT and serum aminotransferase levels indicate the absence of intrinsic liver dysfunction. Elevations in the indirect bilirubin may result from either impaired uptake/conjugation or excess production. The latter, usually from acquired hemolysis, may be a complication of an occult NHL. A work-up for this AIDS-related malignancy was not initiated since the caregivers recognized jaundice as a complication of IDV, which inhibits UDP-glucuronyl transferase and produces a Gilbert's-like syndrome. Physicians can expect to encounter this syndrome even more frequently with ATV. Experienced patients given RTV-boosted ATV have experienced elevations of unconjugated hyper-bilirubinemia in up to 45 percent of cases in clinical trials. However, such elevations do not reflect liver dysfunction and symptomatic jaundice requiring dosage reduction that occurred infrequently (7 to 8 percent of study patients). Counseling patients about this syndrome may promote adherence and prevent self-directed interruptions of ATV that compromise efficacy. The second case of jaundice provides a more formidable diagnostic challenge. The triad of LFT abnormalities (mild elevation of aminotransferases, normal PT, and marked cholestatic jaundice) implies an acute process that is mildly toxic to hepatocytes without affecting their synthetic function. The subacute nature of the patient's cholestatic jaundice suggests either intrahepatic infiltrative disease of the liver or extrahepatic obstruction of the biliary tree, most likely due to the patient's relatively modest level of pain and lack of fever. Despite LFT abnormalities occurring 17 months after a switch in his ART, cumulative drug-related toxicities must still be considered. Ritonavir can produce significant elevations in the AST/ALT, especially with pre-existing chronic liver disease as with hepatitis C virus coinfection. The NRTIs can produce hepatic steatosis, a result of mitochondrial toxicity and impaired fatty acid oxidation. However, jaundice and cholestasis are not typical of the latter syndrome. With a negative contrast CT that excludes parenchymal liver disease, investigation of the biliary tree to assess the presence of AIDS-related cholangitis was the next step. Performing a sphincterotomy or stent placement, and obtaining brushings or biopsy specimens to determine the extent of extrahepatic obstruction may help define a pathogen and be life-saving. The negative results of the ERCP justify the final diagnostic step, a liver biopsy to evaluate microscopic infiltrative disease that might not have been detected on contrast abdominal CT. Examples might include granulomatous disease (MAC), fungal etiologies (histoplasmosis), carcinomatosis (lymphoma, hepatoma, cholangiocarcinoma), and microvascular disease (bacillary angiomatosis). The failure to observe granulomatous inflammation in the liver does not exclude MAC infection, as MAC may involve other peri-aortic or mesenteric lymph nodes. This form of IRIS is unlikely given the abdominal CT findings, lack of systemic complaints, and extended persistence of liver aminotransferases. The nonspecific results of the liver biopsy are a common outcome in advanced AIDS patients with elevated alkaline phosphatase levels. Despite not having identified a pathogen, the biopsy establishes chronic liver disease and prompts re-evaluation and change of treatment to NFV. The subsequent normalization of the patient's aminotransferase levels suggests a prior adverse effect of LPV/r in the setting of unexplained, chronic liver disease. Most importantly, this case highlights the importance of HIV caregivers to review ART for safety when noting chronic liver dysfunction. Patients need to be counseled to minimize acetaminophen use, to consume alcohol in moderation, and to avoid behavior with risk for hepatitis C. Finally, all HIV patients should receive appropriate vaccination against hepatitis A and B if serology shows lack of protective immunity.
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PMID:Clinical vignette in antiretroviral therapy: jaundice. 1498 14

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver disease in the United States. The histologic spectrum of NAFLD ranges from steatosis liver alone to nonalcoholic steatohepatitis (NASH), which is the most serious form of NAFLD. NASH is a progressive fibrotic disease, in which cirrhosis and liver-related death occur in up to 20% and 12%, respectively, over a 10-year period. NASH-associated cirrhosis also can develop into subacute liver failure, progress to hepatocellular carcinoma, and reoccur post-transplantation. In contrast, steatosis alone has a more benign clinical course, although progression to cirrhosis has occurred in 3% of these patients. The major risk factors for fibrosis include diabetes or obesity, an aspartate aminotransferase/alanine aminotransferase ratio of greater than 1, age older than 50, and hepatic histology.
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PMID:The clinical features, diagnosis and natural history of nonalcoholic fatty liver disease. 1533 Oct 61

Laboratory tests for the noninvasive diagnosis of liver fibrosis were studied extensively in the past. However, no test is yet accepted to replace liver biopsy as the gold standard. The establishment of widely accepted semiquantitative histologic scoring systems for the grading and staging of chronic liver disease (e.g., Ishak, Metavir and Scheuer) was paralleled by a significant upturn of research in circulating markers of liver fibrosis. We are now experiencing the renaissance of standard clinical chemistry markers, which are assembled to multiparameter scores (e.g., aspartate aminotransferase-to-platelet ratio index, FibroTest, Forns' index). These scores still require comprehensive evaluation in comparison with histology. Better understanding of the pathophysiology of liver fibrosis provided new options regarding circulating markers of hepatic matrix metabolism (e.g., hyaluronic acid, laminin, matrix metalloproteinase-2, aminoterminal propeptide of procollagen type III and tissue inhibitors of metalloproteinases-1). Several promising studies have been published to date. Thus, a redefinition of the role of liver biopsy is expected in the foreseeable future.
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PMID:Noninvasive diagnosis of fibrosis in chronic liver disease. 1534 64

Fascioliasis is a cause of hepatic disease. Hepatitis B and C viruses are important causative factors in chronic liver disease. In this study, the frequency of hepatitis B (HBV) and/or hepatitis C (HCV) in cases of chronic human fascioliasis is studied. Egg count, indirect haemagglutination test (IHAT), haemoglobin level, total leucocyte and eosinophil counts, serum bilirubin, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and acid phosphatase (ACP) are performed. Serum gamma-glutamyltransferase (GGT), arylsulphatase (ASA) and lipid peroxide levels are determined. Results showed that levels of the latter group of enzymes were increased significantly in cases of chronic fascioliasis. Therefore, determination of GGT, ASA and lipid peroxide should be added to the list of liver function test used to diagnose this disease. Hepatitis B was not detected in any of the 27 chronic fascioliasis patients studied, while HCV was found in only two (7%) cases. However, greater disturbance of biochemical parameters was seen in patients with combined fascioliasis and HCV infection.
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PMID:Human chronic fascioliasis: a possible cause of unexplained abnormal liver tests. 1564 15

Hepatitis C virus (HCV) is the leading cause of chronic liver disease worldwide with a prevalence of approximately 14% in Egypt. IL-10 is a cytokine produced by Th2 cells. It down-regulates the proinflammatory response and modulates hepatic fibrogenesis. IL-12 is produced by antigen presenting cells. It promotes Th1 cell response and has many antiviral properties. Data concerning the Th-1/Th-2 balance in chronic hepatitis C (CH-C) are rather conflicting. Using ELISA, we assessed serum IL-10 and IL-12p40 levels in 66 Egyptian patients with HCV-related liver illness (CH-C, cirrhosis, and HCC), and their relationship to disease activity. Our results showed that spontaneous IL-10 was undetectable in patients with CH-C, HCC or controls. Only 5/22 (23%) of patients with cirrhosis showed detectable levels of IL-10. IL-12p40 was elevated in the patient groups compared to controls (p= 0.01, p= 0.01, p= 0.05 in CH-C, cirrhosis and HCC, respectively). The presence of IL-12p40 was associated with HCV level of viremia and serum AST. Serum ALT level was significantly associated with the level of IL-12p40. IL-12p40 was unrelated to liver histology or fibrosis. We concluded that in the Egyptian patients an augmentation of IL-12p40 and a suppression of IL-10 are both found. Whether this pattern is related to HCV genotype 4, or to the presence of schistosomiasis would need to be further investigated.
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PMID:IL-10 and IL-12p40 in Egyptian patients with HCV-related chronic liver disease. 1571 17


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