Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.1 (aspartate aminotransferase)
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To determine the frequency of liver profile abnormalities in hereditary hemochromatosis, we under took a retrospective survey in 100 patients, all of whom had undergone liver biopsy. Liver histology was compared with the biochemical profile, which included aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, bilirubin and albumin determinations. Mild abnormalities in the AST and ALT levels were seen in more than 65% of patients. Patients with cirrhosis had significantly greater elevations in AST, ALT, and alkaline phosphatase, and a significant decrease in albumin (p less than 0.05). Proband cases had more frequent abnormalities than discovered cases within families. Accordingly, we find that mild abnormalities in the biochemical liver profile are common in hemochromatosis and suggest that patients with an unexplained abnormality in the liver profile should be screened for hemochromatosis with a serum ferritin and transferrin saturation.
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PMID:Biochemical liver profile in hemochromatosis. A survey of 100 patients. 206 47

To determine whether physicians in an academic medical center excluded hemochromatosis as a diagnosis in a population of patients with mildly elevated liver enzyme values, we reviewed 100 charts of patients with both aspartate aminotransferase and alkaline phosphatase levels that were less than twice the upper limit of normal. We analyzed each chart to determine if hemochromatosis would have been excluded by a subsequent workup. Those patients who did not have a complete workup were assigned to one of three categories: (1) no mention was made of abnormal liver enzyme values; (2) liver enzyme values were ascribed to some condition other then hemochromatosis and no definitive workup was done; and (3) the condition of the patient was so poor that assessment did not seem indicated. Ninety of 100 patients were not given a workup to exclude hemochromatosis. Physicians often ignore mild elevations in liver enzyme values.
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PMID:Pursuing mild elevations of liver enzyme values to exclude hemochromatosis. 223 55

Iron overload is a major cause of morbidity and mortality in thalassemia major patients. All chronic liver diseases may be associated with such endocrine symptoms as diabetes mellitus, testicular failure or hypothyroidism. We studied 15 thalassemic patients (12 men and 3 women; age range: 10-50 years, mean: 22.5 years). All patients received blood transfusions, but only some were treated with iron chelation. Seven patients were splenectomized. MRI was performed with an 0.5 T superconducting magnet, using SE T1- and T2-weighted and IR sequences. We used these data with Bloch's equation to calculate T1 and T2 values. Quantitative analysis was made by calculating signal intensity and relaxation times in 8 hepatic regions of interest: marked reduction in hepatic signal intensity and a negative relationship between T1 and serum ferritin (r = 0.646, p < 0.01) and between T2 and serum ferritin (r = 0.688, p < 0.01) were observed. Moreover, a negative relationship was found between hepatic signal intensity and aspartic aminotransferase (r = 0.524, p < 0.05). Our results confirm the value of MRI in the diagnosis and evaluation of hepatic iron overload but an accurate quantitative analysis can be made only when hepatic iron levels are between 1 and 2 mg/g of liver. Even though it is below statistical significance, the negative relationship between signal intensity and aspartic aminotransferase suggests that hepatic hemochromatosis can influence pituitary-thyroid axis and interfere with peripheral hormone metabolism.
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PMID:[Secondary hepatic hemochromatosis: diagnosis and quantification with 0.5 T magnetic resonance. Value and limitations]. 829 5

Hemochromatosis is one of the most frequent genetic diseases among the white populations, affecting one in three hundred persons. Its diagnosis has been radically transformed by the discovery of the HFE gene. In a given individual, the diagnosis can, from now on, be ascertained on the sole association of a plasma transferrin saturation (TS) over 45% and homozygosity for the C282Y mutation. Liver biopsy is only required to search for cirrhosis whenever there is hepatomegaly and/or serum ferritin >1000 ng/ml and/or elevated serum AST. Family screening is mandatory, primarily centered on the siblings. The treatment remains based on venesection therapy which improves many features of the disease (one of the most refractory, however, being the joint signs) and permits normal life expectancy provided the diagnosis is established prior to the development of cirrhosis or of insulin-dependent diabetes. In view of the prevalence, the non-invasive diagnosis, the spontaneous severity and the efficacy of a very simple therapy, hemochromatosis should benefit from population screening. This screening could be based, first, on the assessment of transferrin saturation, followed - when elevated - by the search for the C282Y mutation. The discovery of the HFE gene has also paved the road for the individualization of other types of iron overload syndromes which are not HFE-related.
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PMID:Clinical aspects of hemochromatosis. 1109 95

The aim of the present study was to examine the predictive accuracy of noninvasive clinical and biochemical variables associated with cirrhosis among patients with C282Y homozygous hemochromatosis. Sixteen clinical and laboratory variables were recorded at the time of diagnosis in 193 Canadian C282Y homozygous patients. All patients underwent percutaneous liver biopsy and 27 (14%) had biopsy specimen-proven cirrhosis. Prediction of cirrhosis was assessed first by univariate regression analysis. Variables significantly related to cirrhosis were then evaluated by stepwise linear multivariate regression. Receiver operating characteristic curve analysis of the most informative variables from multivariate analysis was then used to devise a clinically applicable index for the noninvasive prediction of cirrhosis. This index was then validated in 162 C282Y homozygous patients in France. Ferritin, blood platelets, and aspartate transaminase (AST) level were selected for the clinical index. The combination of ferritin levels of 1,000 microg/L or greater, platelet levels of 200 x 10(9)/L or less, and AST levels above the upper limit of normal led to a correct diagnosis of cirrhosis in 77% of Canadian patients. In the French patients, this led to a correct diagnosis of cirrhosis in 90%. In conclusion, in C282Y homozygous patients, a combination of easily measured laboratory variables (ferritin, platelets, AST) can be used to make the diagnosis of cirrhosis in approximately 81% of cases, reducing the need for liver biopsy.
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PMID:Noninvasive prediction of cirrhosis in C282Y-linked hemochromatosis. 1219 60

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

The availability of serum blood chemistries for screening both symptomatic and asymptomatic patients has resulted in a marked increase in the number of abnormal liver chemistry tests that must be interpreted by physicians. Usually the first step in the evaluation of a patient with elevated liver enzymes is to repeat the test to confirm the result. If the result is still abnormal, it seems wise to differentiate between a predominant "necrotic pattern" of liver chemistry, as indicated by an elevation of ALT- or AST-activity or a predominant "cholestatic pattern", as indicated by elevated activities of g-GT and alkaline phosphatase. In patients with elevated serum amino transferases hepatic diseases should be excluded primarily with non-invasive serologic tests. The most common causes of elevated amino transferase levels are chronic hepatitis B and C, autoimmunhepatitis, non-alcoholic steatohepatitis, hemochromatosis, Wilson-disease and (only recently recognized) celiac sprue. In the case of a dominant "cholestatic pattern", primary biliary cirrhosis, primary sclerosing cholangitis, but also drugs and granulomatose hepatitis must be excluded. If non-invasive serologic studies remain inconclusive, ultrasound, mini-laparoscopy and liver biopsy will help to establish the final diagnoses.
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PMID:[The patient with slightly increased liver function tests]. 1574 78

Liver function tests include biochemical parameters (AST, ALT, GGT or Alkaline phosphatase), bilirubin and albumin levels and coagulation tests as prothrombin activity. These tests are commonly used in the routine screening even in symptomatic as in asymptomatic patients, and the right evaluation of the results is of vital importance. Cytolytic elevation in serum aminotransferases: In mild chronic elevation pharmacological toxicity, viral hepatitis, alcoholic and non-alcoholic fatty liver disease and hemochromatosis, should be excluded. Cholestatic elevation os serum enzymes: The first option should be to establish the origin of the alkaline phosphatase elevation, with the evaluation of the GGT levels to confirm the hepatic origin. The next step should be to distinguish the presence of an extrahepatic (biliary obstruction) or intrahepatic (PBC, PSC, drugs, etc) cholestasis, in these cases the most important test should be the abdominal ultrasound, in order to evaluate the biliary system. Hyperbilirubinemia: Non conjugated hyperbilirubinemia (hemolysis, ineffective erythropoiesis, Gilbert or Criggler-Najjar syndromes) and conjugated hyperbilirubinemia, an unusual situation in which Rotor and Dubin-Johnson Syndromes should be considered. The evaluation of albumin and prothrombin levels evaluates the hepatic function per se, allowing to differentiate between acute and chronic diseases. At present, there are not prospective studies to evaluate the efficacy of the liver function tests. To carry out a complete medical history, an appropriate physical examination and the appropriate application of non-invasive diagnostic tests (serology, iron levels, autoimmunity or abdominal ultrasound) allow to perform a right diagnosis in most patients, making more complex tests, including liver biopsy, secondary.
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PMID:[Utility of analytical parameters in the diagnosis of liver disease]. 1737 60

Alpha-1-antitrypsin deficiency (AATD) is a genetic disorder that manifests as pulmonary emphysema, liver cirrhosis and, rarely, as the skin disease panniculitis, and is characterized by low serum levels of AAT, the main protease inhibitor (PI) in human serum. The prevalence in Western Europe and in the USA is estimated at approximately 1 in 2,500 and 1 : 5,000 newborns, and is highly dependent on the Scandinavian descent within the population. The most common deficiency alleles in North Europe are PI Z and PI S, and the majority of individuals with severe AATD are PI type ZZ. The clinical manifestations may widely vary between patients, ranging from asymptomatic in some to fatal liver or lung disease in others. Type ZZ and SZ AATD are risk factors for the development of respiratory symptoms (dyspnoea, coughing), early onset emphysema, and airflow obstruction early in adult life. Environmental factors such as cigarette smoking, and dust exposure are additional risk factors and have been linked to an accelerated progression of this condition. Type ZZ AATD may also lead to the development of acute or chronic liver disease in childhood or adulthood: prolonged jaundice after birth with conjugated hyperbilirubinemia and abnormal liver enzymes are characteristic clinical signs. Cirrhotic liver failure may occur around age 50. In very rare cases, necrotizing panniculitis and secondary vasculitis may occur. AATD is caused by mutations in the SERPINA1 gene encoding AAT, and is inherited as an autosomal recessive trait. The diagnosis can be established by detection of low serum levels of AAT and isoelectric focusing. Differential diagnoses should exclude bleeding disorders or jaundice, viral infection, hemochromatosis, Wilson's disease and autoimmune hepatitis. For treatment of lung disease, intravenous alpha-1-antitrypsin augmentation therapy, annual flu vaccination and a pneumococcal vaccine every 5 years are recommended. Relief of breathlessness may be obtained with long-acting bronchodilators and inhaled corticosteroids. The end-stage liver and lung disease can be treated by organ transplantation. In AATD patients with cirrhosis, prognosis is generally grave.
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PMID:Hereditary alpha-1-antitrypsin deficiency and its clinical consequences. 1856 11

A 58-year-old female patient was transferred by her general practitioner with fatigue, nausea and icterus which had begun 2 weeks prior to admission. Laboratory results revealed acute hepatitis (ALAT [alanine aminotransferase] 3,871 U/l, ASAT [aspartate aminotransferase] 2,004 U/l, bilirubin 6.7 mg/dl, gamma-GT [gamma-glutamyl transferase] 503 U/l). The patient's medical history included genetic hemochromatosis (without cirrhosis). Hepatitis A to C, infection with herpesviruses or Leptospira interrogans were excluded by serologic and molecular biological tests. There was no diagnostic evidence for underlying autoimmune or additional metabolic liver disease. Due to a trip to Africa 5 months earlier, the patient was tested for hepatitis E, leading to positive anti-hepatitis E-IgM and negative anti-hepatitis E-IgG. PCR (polymerase chain reaction) detection of hepatitis E virus (HEV) was positive as well. In conclusion, acute HEV infection was diagnosed. After close reconsideration, the nonfitting incubation period precluded a travel-associated infection. Additionally, there was no evidence for current HEV infections within the patient's social environment, so that a zoonotic origin has to be discussed.
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PMID:[Rare acute hepatitis in a female patient with hemochromatosis: a zoonosis?]. 2045 55


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