Publications by authors named "Richard Hann"

Winter snow from four glacial sites on Svalbard was analyzed for atmospheric deposition of 36 organochlorine pesticides (OCPs) and 7 industrial compounds (OCICs) by GC-high-resolution MS. Thirteen of the OCPs and all OCICs were detected at all sites. Sampling sites are 230 km apart from west to east, but are at varying elevations, ranging from 700 to 1202 m a.

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Prospective and longitudinal epidemiological evidence is needed to assess the association between telomere length and risk of hepatocellular carcinoma (HCC). In 323 cancer-free Korean-American HBV patients with 1-year exclusion window (followed for >1 year and did not develop HCC within 1 year), we measured the relative telomere length (RTL) in baseline serum DNAs and conducted extensive prospective and longitudinal analyses to assess RTL-HCC relationship. We found that long baseline RTL conferred an increased HCC risk compared to short RTL [hazard ratio (HR) = 4.

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We collected 27 tree bark samples near Sauget, IL, where 373 000 mt of polychlorinated biphenyls (PCB) was produced between 1936 and 1977 and 10 245 mt was incinerated from 1971 to 1977. Our goal was observe PCB distribution and apparent movement to residential sites, where 24 of 27 samples were collected. Only one of several waste sites was accessible for sampling.

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Recent studies have demonstrated a potential link between circulating cell-free mitochondrial DNA (mtDNA) content and cancers. However, there is no study evaluating the association between circulating mtDNA as a non-invasive marker of hepatocellular carcinoma (HCC) risk. We conducted a nested case-control study to determine circulating mtDNA content in serum samples from 116 HBV-related HCC cases and 232 frequency-matched cancer-free HBV controls, and evaluate the retrospective association between mtDNA content and HCC risk using logistic regression and their temporal relationship using a mixed effects model.

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Background And Aims: Accumulating evidence has indicated that variations of mitochondrial DNA (mtDNA) content may affect the susceptibility to hepatocellular carcinoma (HCC). However, no study has been conducted to evaluate the association of circulating mtDNA content and the risk of liver cirrhosis, a leading cause of HCC.

Methods: We conducted a nested case-control study including 136 cirrhotic hepatitis B virus (HBV) cases and 136 frequency-matched non-cirrhotic HBV controls.

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Background And Aim: APRI (aspartate aminotransferase [AST] to platelet ratio index) is widely used to assess fibrosis and cirrhosis risk, especially in hepatitis C virus (HCV)-infected patients. Few studies have evaluated APRI and hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) risk. Prospective evidence is needed to assess whether APRI predicts HCC risk in HBV patients.

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The ultimate goal of antiviral therapy for chronic hepatitis B (CHB) is prevention of hepatocellular carcinoma (HCC). Earlier we reported favorable effects of antiviral therapy on survival of HCC patients following curative tumor ablation (Int J Cancer online 14 April 2010; doi: 10.1002/ijc.

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Background: Serum liver enzymes are frequently tested in clinics to aid disease diagnosis. Large observational studies indicated that these enzymes might predict cancer risk and mortality. However, no prospective study has reported on their relationships with the risk of HBV-related hepatocellular carcinoma (HCC).

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Background & Aims: Previous studies have indicated that telomere length is associated with altered risk of various tumours including hepatitis B virus (HBV)-related hepatocellular carcinoma. However, the association between telomere length and the risk of cirrhosis has not been reported.

Methods: In this nested case-control study, we used real-time quantitative PCR to determine the relative telomere length (RTL) in serum DNA samples from 100 HBV-related cirrhosis cases and 100 frequency-matched HBV controls, and evaluated the associations between RTL and cirrhosis risk by logistic regression analyses.

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Background And Aims: Telomere length has emerged as a promising risk predictor of various cancers including hepatocellular carcinoma (HCC). However, the majority of studies in this area measured telomere length in hepatocytes and one in lymphocytes with conflicting results. Moreover, no studies have been reported on using circulating DNA telomere length as a non-invasive HCC biomarker.

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Background: Although serum level of alpha-fetoprotein (AFP) has long been used to complement imaging tests in the screening and diagnosis of hepatocellular carcinoma (HCC), whether it can be used as a predictive marker of long-term risk for developing HCC in patients with hepatitis B virus (HBV) has not been extensively evaluated and thus remains controversial.

Methods: We retrospectively conducted a clinic-based longitudinal cohort study including 617 Korean American patients with HBV who had been followed for up to 22 years (median follow-up time, 6.2 years) to evaluate the association between baseline serum AFP level and the long-term risk of HCC.

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Nicotinic acetylcholine receptors (AChRs) are pentameric proteins that form agonist-gated cation channels through the plasma membrane. AChR agonists and antagonists are potential candidates for the treatment of neurodegenerative diseases. Cembranoids are naturally occurring diterpenoids that contain a 14-carbon ring.

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Objectives: During the past decades, the influx of immigrants from hepatitis B virus (HBV) endemic regions has brought significant changes in the prevalence of HBV-associated liver diseases and hepatocellular carcinoma (HCC) in the United States. Our program, which was intended to identify those in need of hepatitis B vaccination, helped us to learn of the natural history of HBV infection in Korean Americans.

Methods: Between November of 1988 and May 1990, we screened 6,130 Korean Americans in the eastern United States for HBV infection.

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The alpha-conotoxins MI and GI display stronger affinities for the alphagamma agonist site on the Torpedo californica electrocyte nicotinic acetylcholine receptor (ACHR) than for the alphadelta agonist site, while alpha-conotoxin SI binds with the same affinity to both sites. Prior studies reported that the arginine at position 9 on GI and the tyrosine at position 111 on the receptor gamma subunit were responsible for the stronger alphagamma affinities of GI and MI, respectively. This study was undertaken to determine if the alpha-conotoxin midchain cationic residues interact with Torpedo gammaY111.

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