Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clinical charts of 80 infants younger than 1 year who presented over a 14-year period (1986 to 2000) with acute liver failure (ALF), defined as prolonged prothrombin time greater than 17 seconds and decrease of clotting factor V plasma level below 50% of normal, were reviewed retrospectively. The main causes of ALF were inherited metabolic disorders in 42.5% of cases, including mitochondrial respiratory chain disorders in 17, type I hereditary tyrosinemia in 12, and urea cycle disorders in 2; neonatal hemochromatosis in 16% of cases; and acute viral hepatitis in 15% of cases (hepatitis B in 6, herpes virus type 6 in 4, and herpes simplex virus type 1 in 2). The cause of ALF remained undetermined in 16% of cases. A total of 19 (24%) infants survived without orthotopic liver transplantation; 38 (47%) infants died from sepsis, multiple organ failure, or because the underlying disease contraindicated orthotopic liver transplantation (12 [15%] infants), and 23 (29%) infants underwent orthotopic liver transplantation within 12 months from onset, 12 of whom are alive with a mean follow-up period of 5.2 years from orthotopic liver transplantation. We conclude that ALF during the first year of life is a severe condition with poor prognosis, despite the advent of liver transplantation.
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PMID:Acute liver failure in infancy: a 14-year experience of a pediatric liver transplantation center. 1174 17

Hepatocellular carcinoma (HCC) is the most common malignant tumor of males in the world, with an incidence of 1,000,000 new cases a year. It is endemic in Southeast Asia and Sub-Saharan Africa. Risk factors include chronic infection with hepatitis B virus (HBV) and hepatitis C virus (HCV), Aflatoxin B1 uptake, hemochromatosis, and alpha1 -antitripsin deficiency. Epidemiological studies provide evidence for the association of HCC with HBV infection. The incidence of HCC is high in regions hyperendemic for HBV. Chronic carrier state and maternal-infant transmission are important factors in the development of HCC. Evidence of direct oncogenic effect of H BV is well established, HCCs contain viral DNA sequences integrated into hepatocyte DNA that act as random insertional mutagens, and these sites are near genes involved in the control of proliferation and differentiation. The mechanism of hepatitis C virus in hepatocarcinogenesis is still imprecise but a high percentage of cases are related to this virus. Chronic alcohol consumption and cirrhosis are cofactors that increase the development of HCC in patients with chronic viral infection. In experimental carcinogenesis a multipotential element called oval cell proliferates in the early stages. The cellular events are accompanied by increased expression of several growth factors that enhance the survival of carcinogen-activated cells by suppressing apoptosis and increasing elements entering the cell cycle. Hepatic carcinogenesis is a complex process associated with accumulation of genetic and epigenetic changes that run through steps of initiation, promotion and progression. Activation of oncogenes of the "ras" family and others has been detected during chemically-induced HCC in rodents, but there is little evidence of such activation in human tumors. The role of tumor supressor genes such as retinoblastoma (RB) and P53 genes has been documented. Aflatoxin B1 that contaminates foods in endemic areas has a clear role in hepatocarcinogenesis. Metabolites of this toxin promote apurinic sites and G to T mutations in chromosomal DNA, the third base of codon 249 of the P53 gene is preferentially targeted to form aducts with aflatoxin B1, and this mutation has been specifically identified in HBV infection. Histological and cytological criteria for the diagnosis of HCC are well established and are based in architectural and cytological changes. An important issue is the diagnosis of liver "nodules" detected by image, from which small biopsies or aspiration material is obtained. Special studies such as reticulin, CD34, cytokeratin profile, and MOC-31 can be very useful for the differential diagnosis of primary and metastatic tumors. Telomerase activity has been found in HCC and negative in pericancerous tissue. It is more pronounced in poorly differentiated tumors and correlates with factors of clinical importance, such as prognosis and recurrences. Cells of well-differentiated HCC have an ultrastructural appearance similar to normal hepatocytes. During the process of dedifferentiation, there is progressive loss of organization of intracellular organelles. The cell cohesion is lost, intercellular gaps with microvilli appear, the sinusoids become capillarized, and reparative changes are seen in the spaces of Disse. A variety of inclusions, such as Mallory bodies, granular material, secondary lysosomes, and Dubin-Johnson pigment, have been described. Fibrolamellar carcinoma has a characteristic histological picture and ultrastructurally oncocytic features. Neuroendocrine granules and combination of HCC with bile duct carcinoma are seen by electron microscopy.
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PMID:Hepatocellular carcinoma: an update. 1178 14

The incidence of hepatocellular carcinoma is increasing in many countries. The estimated number of new cases annually is over 500,000, and the yearly incidence comprises between 2.5 and 7% of patients with liver cirrhosis. The incidence varies between different geographic areas, being higher in developing areas; males are predominantly affected, with a 2:3 male/female ratio. The heterogeneous geographic distribution reflects the epidemiologic impact of the main etiologic factors and environmental risk, which are the hepatitis B (HBV) and hepatitis C (HCV) viruses. The percentage of cases of hepatocellular carcinoma attributable to HBV worldwide is 52.3% and is higher in Asia where the seroprevalence of HBsAg in the population is high. However, the vaccination campaign against this virus in some eastern countries has tended to lower the incidence of new cases of hepatocellular carcinoma. The percentage of cases of hepatocellular carcinoma attributable to HCV is 25%, and it is more prevalent in Japan, Spain, and Italy where the association between hepatocellular carcinoma and antibodies to HCV ranges between 50 and 70%. In most cases hepatocellular carcinoma develops in cirrhotic livers, where the persistent proliferation of liver cells represents the key factor of progression to hepatocellular carcinoma independent of the etiology. Another minor risk factor is aflatoxin B1 consumption, which is responsible for most cases of hepatocellular carcinoma in Africa, where the consumption of contaminated foods is common. Other known risk factors are some hereditary diseases, such as hemochromatosis, porphyria cutanea tarda, hereditary tyrosinemia, and alpha1 anti-trypsin deficiency. The natural history of hepatocellular carcinoma is heterogeneous and is influenced by nodule dimension, the mono- or plurifocality of lesions at diagnosis, the growth rate of the tumor, and the stage of the underlying cirrhosis. Available data to date suggest that tumor growth in a cirrhotic liver is variable and that the time in which a lesion in undetectable until it becomes 2 cm is between 4 and 12 months. Therefore, the suggested interval for surveillance screening with ultrasound in patients with liver cirrhosis has been set at 6 months. Patients who should benefit from screening programs are those who would be treated with curative therapy if diagnosed with hepatocellular carcinoma. Thus, the ideal target population should be limited to Child-Pugh's class A cirrhotic patients without significant comorbidity.
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PMID:Epidemiology, risk factors, and natural history of hepatocellular carcinoma. 1209 24

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in some areas of the world with an extremely poor prognosis. The major etiologic risk factors for HCC development include toxins (alcohol, aflatoxin B1), androgens and estrogens, hepatitis B virus (HBV) and hepatitis C virus (HCV) infection as well as various inherited metabolic disorders, such as alpha-1-antitrypsin deficiency and hemochromatosis. The molecular pathogenesis of HCC development is very complex and involves alterations in the structure or expression of several tumor suppressor genes, oncogenes and, possibly, mechanisms leading to a genetic instability due to mismatch repair deficiency or chromosomal instability and aneuploidy due to defective chromosomal segregation. Central to the molecular pathogenesis of HCCs are mutations of various genes and a genetic instability which in most cases result from chronic liver disease and the associated enhanced liver cell regeneration and mitotic activity. The prognosis of HCC patients is generally very poor. Most studies report a five year survival rate of less than 5% in symptomatic HCC patients. Furthermore, these tumors have been shown to be quite resistant to radio- or chemotherapy. Investigations of the natural history and clinical course of HCCs revealed long-term survival of patients only with small asymptomatic HCCs that could be treated surgically or by non-surgical interventions. Apart from exploring and refining new HCC treatment strategies, the implementation of existing and the development of novel measures to prevent HCC development are most important. Primary HCC prevention includes among others universal hepatitis B vaccination, antiviral therapy of patients with chronic hepatitis B or C, reduction of food contamination with aflatoxins, elimination of excessive alcohol etc. Also for some genetic diseases there is the potential for HCC prevention by identifying affected family members at risk, such as patients with precirrhotic hemochromatosis. Reduction of iron overload by phlebotomy has been shown to eliminate the progression hemochromatosis to liver cirrhosis and HCC. Preventive measures, therefore, should have a major impact on the incidence of HCCs in patients with acquired and inherited liver diseases. Further, the prevention of a local recurrence or the development of new HCC lesions in patients after successful surgical or non-surgical HCC treatment (secondary prevention) is of paramount importance and is expected to significantly improve disease-free and overall patient survival. Based on rapid scientific advances, molecular diagnosis, gene therapy and molecular prevention are becoming increasingly part of our patient management and will eventually complement and in part replace existing diagnostic, therapeutic and preventive strategies. Overall, this should result in a reduction of the incidence of HCCs, one of the most devastating malignancies worldwide.
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PMID:Molecular targets for prevention of hepatocellular carcinoma. 1214 24

Hepatocellular carcinoma (HCC) is the most common hepatic malignancy worldwide. The primary risk factor for the development of HCC is cirrhosis. Even patients without cirrhosis who develop HCC are typically found to have some underlying hepatic abnormality, such as steatohepatitis or chronic viral hepatitis. Although cirrhosis of any cause increases the risk of developing HCC, cirrhosis associated with chronic hepatitis B or C virus infection or hemochromatosis carries the greatest risk. Additional factors such as patient age and sex, duration and severity of liver disease, concurrent alcohol or aflatoxin exposure, liver histology, and alpha-fetoprotein levels also contribute to the relative risk of developing HCC. Vaccination programs aimed at preventing hepatitis B virus infection have been very successful in lowering the incidence of HCC in some areas of the world. Interferon-based therapy, which may control the inflammatory activity in chronic hepatitis C, also holds promise in preventing HCC. Other novel chemopreventative agents, such as glycyrrhizin and polyprenoic acid, may also have a role in preventing HCC, but they require further study before they can be recommended for widespread use.
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PMID:Hepatocellular carcinoma: the high-risk patient. 1239 10

Chromogranin A is a cellular marker forneuroendocrine tumors. Elevated levels of chromogranin A are also found in patients with cancers of epithelial origin when neuroendocrine differentiation occurs, which is associated with a poor prognosis. We investigated the prevalence of serum levels of chromogranin A in patients with primary liver cancer. Seventy-nine patients (65 males, mean age 67.6 years, range 48-88 years) with liver cirrhosis and hepatocellular carcinoma were studied. The etiology of cirrhosis was identified as due to hepatitis C virus infection in 47 patients, to hepatitis C virus and alcohol in 7, to alcohol alone in 14, to hepatitis C and B virus in 2, and to hepatitis B virus alone in 4. Of the remaining patients, 2 suffered from hemochromatosis and 3 had cryptogenic cirrhosis. According to the Child-Pugh's score, 54 patients belonged to class A, 22 to class B, and 3 to class C. The concentration of chromogranin A was measured in serum with a commercial solid-phase two-site immunoradiometric assay. Elevated serum levels of chromogranin A were found in 32 of 79 patients (43%). Levels over 600 ng/ml were present in 7 of 76 patients (9.2%), all of whom had very high serum levels of alpha-fetoprotein. Hence, elevated serum levels of chromogranin A are present in over one third of patients with hepatocellular carcinoma. It is therefore possible that some hepatocellular carcinomas could acquire a neuroendocrine differentiation. We propose further studies to ascertain whether serum levels of chromogranin A are useful as a prognostic marker for hepatocellular carcinoma as in prostate cancer.
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PMID:Elevated serum chromogranin A in patients with hepatocellular carcinoma. 1244 8

Primary hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. However, the viral-chemical etiology as well as molecular mechanisms of HCC pathogenesis remains largely unknown. Recent studies in our laboratory have identified several potential factors that may contribute to the pathogenesis of HCC. Oxidative stress and chronic inflammation have been linked to an increased risk of liver cancer. For example, oxyradical overload diseases such as Wilson disease and hemochromatosis result in the generation of oxygen/nitrogen species that can cause mutations in the p53 tumor suppressor gene. The Hepatitis B virus X gene (HBx), a viral transactivator with oncogenic potentials, has been shown to bind to and inactivate p53-mediated apoptosis. HBx mutants derived from HCC have a diminished ability to act as a transactivator. However, they still retain the ability to bind to and abrogate p53-mediated apoptosis. The comparison of gene expression profiles between HBx-expressing primary human hepatocytes and HBV-infected liver samples by cDNA microarrays indicate a unique alteration of a subset of oncogenes and tumor suppressor genes including p53. Our studies implicate both viral and endogenous chemical processes in the etiology of HCC, and p53 may be a common target for the inactivation during liver carcinogenesis.
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PMID:Molecular pathogenesis of human hepatocellular carcinoma. 1250 83

Primary hepatocellular carcinoma (HCC) is one of the most common malignancies and has the fourth highest mortality rate worldwide. The major risk factors, including chronic infections with the hepatitis B or C virus, are exposure to dietary aflatoxin B1(AFB1), vinyl chloride, or alcohol consumption. Southern China and sub-Saharan Africa have the highest dietary AFB1 exposure, making it and hepatitis B virus (HBV) the major causes of cancer mortality in these geographic areas. Recent studies have discovered genetic and epigenetic changes involved in the molecular pathogenesis of HCC, including somatic mutations in the p53 tumor suppressor gene (TP53). AFB1 induces typical G:C to T:A transversions at the third base in codon 249 of p53. Chronic active hepatitis B and C (HCV) infection, and further inflammatory and oxyradical disorders including Wilson disease (WD) or hemochromatosis, generate reactive oxygen/nitrogen species that can damage DNA and mutate the p53 gene. The X gene of HBV (HBx) is the most common open reading frame integrated into the host genome in HCC. The integrated HBx is frequently mutated and has a diminished ability to function as a transcriptional cotransactivator and to activate the NF-kappa B pathway. However, the mutant HBx proteins still retain their ability to bind to and abrogate p53-mediated apoptosis. In summary, both viruses and chemicals are implicated in the etiology and molecular pathogenesis of HCC. The resultant molecular changes in the ras and Wnt signal-transduction pathways, and the p53 and Rb tumor suppressor pathways significantly contribute to liver carcinogenesis
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PMID:TP53 and liver carcinogenesis. 1261 6

A number of factors, including increased iron stores and alcohol consumption, are known to be associated with the development of porphyria cutanea tarda (PCT) in susceptible individuals. Recent reports have described a significant association between inheritance of the C282Y and H63D mutations in the HFE gene, associated with genetic hemochromatosis (GH) and PCT. A strong association between hepatitis C virus infection and PCT has also been demonstrated, while case reports record a link between human immunodeficiency virus (HIV) and PCT. We have investigated the frequency of these factors in a racially-mixed population of patients with PCT in Cape Town, South Africa. 57 patients with PCT drawn from three ethnic groups were screened for the presence of the C282Y and H63D mutations linked to GH, and the prevalences were compared with corresponding healthy control populations. The seroprevalence of markers for HCV, hepatitis B (HBV) and HIV infection were examined in 28 of these. In the control populations, we found that both the C282Y and H63D mutations are highly prevalent in South Africans of European origin. In a population of mixed or Asian origin, the C282Y mutation is very rare whereas the H63D mutation is common. Neither mutation was encountered in any African subject. Both mutations are associated with PCT, but the association is dependent on the ethnic origins of the population to which the patient belongs. In contrast to other studies, HCV infection is numerically unimportant in PCT in our patients. HIV infection is increasingly encountered in our patients with PCT, but the strength of the association cannot be determined in view of the high background prevalence of HIV infection in some sectors of the South African population. The contribution of specific risk factors may be heavily dependent on the population from which patients are drawn, and care should be taken in extrapolating from observations in one racial or geographic population to any other.
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PMID:Porphyria cutanea tarda: the etiological importance of mutations in the HFE gene and viral infection is population-dependent. 1269 43

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


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