Hepatitis viruses and hepatocellular carcinoma

Of the hepatitis viruses that have been identified and their pathological consequences characterised, three - hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV) - have been implicated as risk factors for hepatocellular carcinoma (HCC) in humans. Sufficient evidence is now available to justify the conclusions that chronic infection with HBV and HCV, but not HDV, are causes of HCC. Hepatocellular carcinogenesis is a complex step-wise process that evolves over many years, and the precise way(s) in which these two viruses induce malignant transformation remain uncertain. The observation that HBV DNA is integrated into cellular DNA in the great majority of, and perhaps all, HBV-related HCCs, whereas replicative intermediates of HCV do not insert into host DNA in HCVrelated HCC, makes it very likely that different pathogenic mechanisms operate in HBV- and HCV-induced HCC. Indeed, evidence is mounting that both direct and indirect mechanisms, and often the two together, are involved in the genesis of HBV-related HCC, but that HCV appears only to induce HCC indirectly by causing chronic necroinflammatory hepatic disease which in turn is responsible for tumour formation. There is some evidence that the two viruses may interact in the development of HCC, but this remains to be proven. Animal models - other members of the hepadnavirus family (to which HBV belongs) that also cause HCC in their respective animal hosts, and transgenic mice into which sequences of HBV DNA have been inserted - are proving useful in elucidating putative mechanisms of HBV-related hepatocellular carcinogenesis, but no models for studying HCV-induced HCC are yet available. Whatever the pathogenesis of HBV-induced and HCV-induced HCC, the viruses do not act alone but in conjunction with other environmental carcinogens and a number of host factors

Thyroxine-binding globulin, hyperthyroxinemia and hepatocellular carcinoma

To determine serum thyroxine-binding globulin (TBG) levels, we used radioimmunoassay, and compared the results obtained with other tests in 231 patients with chronic hepatitis B virus infection to evaluate its clinical implications. All of these patients were hepatitis B surface antigen (HBsAg)-positive. Among them, 38 patients had hepatocellular carcinoma (HCC), 18 had chronic persistent hepatitis, 70 had chronic lobular or active hepatitis (grouped as CAH), 31 had active cirrhosis (AC), 25 had inactive cirrhosis, 20 had decompensated cirrhosis, and 29 were “healthy” HBsAg carriers. Twenty-seven patients with acute hepatitis, 12 with cancer metastasis to the liver, and 81 normal adults served as disease or normal controls. The results showed that serum TBG level increased significantly in patients with CAH, AC, or HCC. Serum TBG did not correlate with albumin or bilirubin level, but correlated with alanine aminotransferase (ALT) positively in patients with CAH ( p < 0.001) and negatively in patients with HCC ( p < 0.01) (slope difference p < 0.05). Serial determination of serum TBG and ALT also showed parallel changes in 15 patients with CAH, but not in nine patients with HCC. In contrast, the fall and rise of serum TBG levels in patients with HCC coincided with tumor resection and recurrence. The data suggest that serum TBG elevation in patients with hepatitis activity is the result of hepatocellular damage, whereas that in patients with HCC is due to increased synthesis. Whether serum TBG elevation without concomitant rise of ALT could be used as a marker of HCC awaits further study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38358/1/1840130434_ftp.pd

Effects of Exogenous Antioxidants on Dietary Iron Overload

In dietary iron overload, excess hepatic iron promotes liver damage. The aim was to attenuate free radical-induced liver damage using vitamins. Four groups of 60 Wistar rats were studied: group 1 (control) was fed normal diet, group 2 (Fe) 2.5% pentacarbonyl iron (CI) followed by 0.5% Ferrocene, group 3 (Fe + V gp) CI, Ferrocene, plus vitamins A and E (42× and 10× RDA, respectively), group 4 (Fe – V gp) CI, Ferrocene diet, minus vitamins A and E. At 20 months, glutathione peroxidase (GPx), superoxide dismutase (SOD), Oxygen Radical Absorbance Capacity (ORAC), Ames mutagenicity test, AST, ALT and 4-hydroxynonenal (4-HNE) immunohistochemistry were measured. 8OHdG levels of the Fe + V and Fe – V groups were 346 ± 117 and 455 ± 151, ng/g w.wt, respectively. Fe + V and Fe – V differences were significant (p<0.005). A positive correlation between DNA damage and mutagenesis existed (p<0.005) within the iron-fed gps. AST levels for Fe + V and Fe – V groups were 134.6 ± 48.6 IU and 202.2 ± 50.5 IU, respectively. Similarly, ALT levels were 234.6 ± 48.3 IU and 329.0 ± 48.6 IU, respectively. However, Fe – V and Fe + V groups transaminases were statistically insignificant. 4-HNE was detected in Fe + V and Fe – V gp livers. Vitamins A and E could not prevent hepatic damage

A case-control study for differences among hepatitis B virus infections of genotypes A (subtypes Aa and Ae) and D

There are two subtypes of hepatitis B virus genotype A (HBV/A) and they are provisionally designated Aa (a standing for Africa/Asia) and Ae (e for Europe). In a case-control study, 78 HBV/Aa, 78HBV/Ae, and 78HBV/D carriers from several countries were compared. The prevalence of HBe antigen (HBeAg) in serum was significantly lower in carriers of HBV/Aa than in carriers of HBV/Ae (31% vs. 49%; P = .033), with a difference more obvious in the carriers aged 30 years or younger (34% vs. 67%; P = .029). HBV DNA levels in the carriers of HBV/Aa (median, 3.46 log copies/mL; 95% CI, 2.93-3.95) were significantly lower than those of carriers of HBV/Ae (6.09 log copies/mL; 95% CI, 4.24-7.64) or of carriers of HBV/D (5.48 log copies/mL; 95% CI, 4.06-7.02), regardless of the HBeAg status (P &lt; .001). The most specific and frequent substitutions in 54 HBV/Aa isolates were double substitutions for T1809 (100%) and T1812 (96%) immediately upstream of the precore initiation codon, which would interfere with the translation of HBeAg in HBV/Aa infections. They were not detected in 57 HBV/Ae or 61 HBV/D isolates examined. The double mutation in the core promoter (T1762/A1764) was more frequent in both HBV/Aa (50%) and HBV/Ae (44%) than in HBV/D isolates (25%; P &lt; .01), whereas the precore mutation (A1896) occurred in HBV/D isolates only (48%; P &lt; .0001). In conclusion, the clearance of HBeAg from serum may occur by different mechanisms in HBV/Aa, HBV/Ae, and HBV/D infections, which may influence clinical manifestations in the Western countries where both genotypes A and D are prevalent

The distribution of pond snail communities across a landscape: separating out the influence of spatial position from local habitat quality for ponds in south-east Northumberland, UK

Ponds support a rich biodiversity because the heterogeneity of individual ponds creates, at the landscape scale, a diversity of habitats for wildlife. The distribution of pond animals and plants will be influenced by both the local conditions within a pond and the spatial distribution of ponds across the landscape. Separating out the local from the spatial is difficult because the two are often linked. Pond snails are likely to be affected by both local conditions, e.g. water hardness, and spatial patterns, e.g. distance between ponds, but studies of snail communities struggle distinguishing between the two. In this study, communities of snails were recorded from 52 ponds in a biogeographically coherent landscape in north-east England. The distribution of snail communities was compared to local environments characterised by the macrophyte communities within each pond and to the spatial pattern of ponds throughout the landscape. Mantel tests were used to partial out the local versus the landscape respective influences. Snail communities became more similar in ponds that were closer together and in ponds with similar macrophyte communities as both the local and the landscape scale were important for this group of animals. Data were collected from several types of ponds, including those created on nature reserves specifically for wildlife, old field ponds (at least 150 years old) primarily created for watering livestock and subsidence ponds outside protected areas or amongst coastal dunes. No one pond type supported all the species. Larger, deeper ponds on nature reserves had the highest numbers of species within individual ponds but shallow, temporary sites on farm land supported a distinct temporary water fauna. The conservation of pond snails in this region requires a diversity of pond types rather than one idealised type and ponds scattered throughout the area at a variety of sites, not just concentrated on nature reserves

Viral expression and molecular profiling in liver tissue versus microdissected hepatocytes in hepatitis B virus - associated hepatocellular carcinoma

Abstract Background The molecular mechanisms whereby hepatitis B virus (HBV) induces hepatocellular carcinoma (HCC) remain elusive. We used genomic and molecular techniques to investigate host-virus interactions by studying multiple areas of the same liver from patients with HCC. Methods We compared the gene signature of whole liver tissue (WLT) versus laser capture-microdissected (LCM) hepatocytes along with the intrahepatic expression of HBV. Gene expression profiling was performed on up to 17 WLT specimens obtained at various distances from the tumor center from individual livers of 11 patients with HCC and on selected LCM samples. HBV markers in liver and serum were determined by real-time polymerase chain reaction (PCR) and confocal immunofluorescence. Results Analysis of 5 areas of the liver showed a sharp change in gene expression between the immediate perilesional area and tumor periphery that correlated with a significant decrease in the intrahepatic expression of HB surface antigen (HBsAg). The tumor was characterized by a large preponderance of down-regulated genes, mostly involved in the metabolism of lipids and fatty acids, glucose, amino acids and drugs, with down-regulation of pathways involved in the activation of PXR/RXR and PPARα/RXRα nuclear receptors, comprising PGC-1α and FOXO1, two key regulators critically involved not only in the metabolic functions of the liver but also in the life cycle of HBV, acting as essential transcription factors for viral gene expression. These findings were confirmed by gene expression of microdissected hepatocytes. Moreover, LCM of malignant hepatocytes also revealed up-regulation of unique genes associated with cancer and signaling pathways, including two novel HCC-associated cancer testis antigen genes, NUF2 and TTK. Conclusions Integrated gene expression profiling of whole liver tissue with that of microdissected hepatocytes demonstrated that HBV-associated HCC is characterized by a metabolism switch-off and by a significant reduction in HBsAg. LCM proved to be a critical tool to validate gene signatures associated with HCC and to identify genes that may play a role in hepatocarcinogenesis, opening new perspectives for the discovery of novel diagnostic markers and therapeutic targets

IMILAST: a community effort to intercompare extratropical cyclone detection and tracking algorithms

The variability of results from different automated methods of detection and tracking of extratropical cyclones is assessed in order to identify uncertainties related to the choice of method. Fifteen international teams applied their own algorithms to the same dataset—the period 1989–2009 of interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERAInterim) data. This experiment is part of the community project Intercomparison of Mid Latitude Storm Diagnostics (IMILAST; see www.proclim.ch/imilast/index.html). The spread of results for cyclone frequency, intensity, life cycle, and track location is presented to illustrate the impact of using different methods. Globally, methods agree well for geographical distribution in large oceanic regions, interannual variability of cyclone numbers, geographical patterns of strong trends, and distribution shape for many life cycle characteristics. In contrast, the largest disparities exist for the total numbers of cyclones, the detection of weak cyclones, and distribution in some densely populated regions. Consistency between methods is better for strong cyclones than for shallow ones. Two case studies of relatively large, intense cyclones reveal that the identification of the most intense part of the life cycle of these events is robust between methods, but considerable differences exist during the development and the dissolution phases

Multifactor effects and evidence of potential interaction between complement factor H Y402H and LOC387715 A69S in age-related macular degeneration

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