Epigenetic Regulation of Hepatitis B Virus Replication

Hepatitis B virus (HBV) is the most important cause of chronic viral hepatitis worldwide. The genome of HBV is 3.2 kb partially double-stranded DNA, which is translocated to the nuclei of infected hepatocytes and converted to complete double-stranded DNA, aka covalently closed circular DNA (cccDNA). Typical course of chronic HBV infection results in inactive carrier state with clearance of viral particles in the bloodstream. However, the cccDNA can be detected in the hepatocytes from inactive carriers by sensitive methods. It has been increasingly known that epigenetic mechanisms contribute to the control of HBV replication in the inactive stage of HBV infection. Histone modification and DNA methylation have been identified in the HBV cccDNA, leading to modification of transcriptional activity. The understanding of epigenetic control of transcription will shed light on the development of new therapeutic strategy against HBV cccDNA

Korean University Students' Awareness of Plagiarism in Summary Writings

The present study examines Korean university students' awareness of plagiarism in summary writings. Twenty nine university students were asked to write English summaries of an English source text. They were then given the instruction on what is plagiarism and why they should avoid it. Finally, they were again asked to write the second summary writings of the same source text. The degrees of exact copying in the first and second summaries were compared based on the meaningful unit. The results showed that a 3-hour class session, which mainly focused on the warnings against plagiarism, had an enormous effect on the reduction of the copying degree in students' summary writing. The students illustrated the ability to summarize the text in their own words in the second summaries. They mainly copied in the first summary because they lacked the understanding of the notion of plagiarism It was suggested that students should be informed of the concept of plagiarism and be trained to paraphrase and write in their own words

Electrogenic transport and K(+) ion channel expression by the human endolymphatic sac epithelium.

The endolymphatic sac (ES) is a cystic organ that is a part of the inner ear and is connected to the cochlea and vestibule. The ES is thought to be involved in inner ear ion homeostasis and fluid volume regulation for the maintenance of hearing and balance function. Many ion channels, transporters, and exchangers have been identified in the ES luminal epithelium, mainly in animal studies, but there has been no functional study investigating ion transport using human ES tissue. We designed the first functional experiments on electrogenic transport in human ES and investigated the contribution of K(+) channels in the electrogenic transport, which has been rarely identified, even in animal studies, using electrophysiological/pharmacological and molecular biological methods. As a result, we identified functional and molecular evidence for the essential participation of K(+) channels in the electrogenic transport of human ES epithelium. The identified K(+) channels involved in the electrogenic transport were KCNN2, KCNJ14, KCNK2, and KCNK6, and the K(+) transports via those channels are thought to play an important role in the maintenance of the unique ionic milieu of the inner ear fluid

Molecular Weight Dependent Glucose Lowering Effect of Low Molecular Weight Chitosan Oligosaccharide (GO2KA1) on Postprandial Blood Glucose Level in SD Rats Model

Abstract This research investigated the effect of enzymatically digested low molecular weight (MW) chitosan oligosaccharide on type 2 diabetes prevention. Three different chitosan oligosaccharide samples with varying MW were evaluated in vitro for inhibition of rat small intestinal α-glucosidase and porcine pancreatic α-amylase (GO2KA1; \u3c1000 Da, GO2KA2; 1000–10,000 Da, GO2KA3; MW \u3e 10,000 Da). The in vitro results showed that all tested samples had similar rat α-glucosidase inhibitory and porcine α-amylase inhibitory activity. Based on these observations, we decided to further investigate the effect of all three samples at a dose of 0.1 g/kg, on reducing postprandial blood glucose levels in Sprague-Dawley (SD) rat model after sucrose loading test. In the animal trial, all tested samples had postprandial blood glucose reduction effect, when compared to control, however GO2KA1 supplementation had the strongest effect. The glucose peak (Cmax) for GO2KA1 and control was 152 mg/dL and 193 mg/dL, respectively. The area under the blood glucose-time curve (AUC) for GO2KA1 and control was 262 h mg/dL and 305 h mg/dL, respectively. Furthermore, the time of peak plasma concentration of blood glucose (Tmax) for GO2KA1 was significantly delayed (0.9 h) compared to control (0.5 h). These results suggest that GO2KA1 could have a beneficial effect for blood glucose management relevant to diabetes prevention in normal and pre-diabetic individuals. The suggested mechanism of action is via inhibition of the carbohydrate hydrolysis enzyme α-glucosidase and since GO2KA1 (MW \u3c 1000 Da) had higher in vivo effect, we hypothesize that it is more readily absorbed and might exert further biological effect once it is absorbed in the blood stream, relevant to blood glucose management

Anti-malarial activity of 6-(8'Z-pentadecenyl)-salicylic acid from Viola websteri in mice

<p>Abstract</p> <p>Background</p> <p>Petroleum ether extracts of <it>Viola websteri </it>Hemsl (Violaceae) were reported to have anti-plasmodial activity against <it>Plasmodium falciparum in vitro</it>, with this activity being largely attributable to 6-(8'Z-pentadecenyl)-salicylic acid (6-SA).</p> <p>Methods</p> <p>The schizontocidal activity of 6-SA on early <it>Plasmodium berghei </it>infections was evaluated in a four-day test. The possible 'repository' activity of 6-SA was assessed using the method described by Peters. The median lethal dose (LD₅₀) of 6-SA, when given intraperitoneally, was also determined using uninfected ICR mice and the method of Lorke.</p> <p>Results</p> <p>In the present study, 6-SA was found to have anti-malarial activity <it>in vivo</it>, when tested against <it>P. berghei </it>in mice. 6-SA at 5, 10 and 25 mg/kg·day exhibited a significant blood schizontocidal activity in four-day early infections, repository evaluations and established infections with a significant mean survival time comparable to that of the standard drug, chloroquine (5 mg/kg·day).</p> <p>Conclusion</p> <p>6-SA possesses a moderate anti-malarial activity that could be exploited for malaria therapy.</p

Preparation of polylactide-co-glycolide nanoparticles incorporating celecoxib and their antitumor activity against brain tumor cells

Tae-Ho Kim1*, Young-Il Jeong2*, Shu-Guang Jin2, Jian Pei2, Tae-Young Jung1, Kyung-Sub Moon1, In-Young Kim1, Sam-Suk Kang1, Shin Jung1,21Department of Neurosurgery, 2Brain Tumor Research Laboratory, Chonnam National University Research Institute of Medical Science, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Republic of Korea *These authors contributed equally to this work. Background: Celecoxib, a cyclo-oxygenase (COX)-2 inhibitor, has been reported to mediate growth inhibitory effects and to induce apoptosis in various cancer cell lines. In this study, we examined the potential effects of celecoxib on glioma cell proliferation, migration, and inhibition of COX-2 expression in vitro. Methods: Celecoxib was incorporated into poly DL-lactide-co-glycolide (PLGA) nanoparticles for antitumor drug delivery. Results: PLGA nanoparticles incorporating celecoxib had spherical shapes and their particle sizes were in the range of 50&amp;ndash;200 nm. Drug-loading efficiency was not significantly changed according to the solvent used, except for acetone. Celecoxib was released from the PLGA nanoparticles for more than 2 days, and the higher the drug content, the longer the duration of drug release. PLGA nanoparticles incorporating celecoxib showed cytotoxicity against U87MG tumor cells similar to that of celecoxib administered alone. Furthermore, celecoxib did not affect the degree of migration of U87MG cells. PLGA nanoparticles incorporating celecoxib showed dose-dependent cytotoxicity similar to that of celecoxib alone in C6 rat glioma cells. Western blot assay of the C6 cells showed that neither celecoxib alone nor PLGA nanoparticles incorporating celecoxib affected COX-2 expression. Conclusion: PLGA nanoparticles incorporating celecoxib had antitumor activity similar to that of celecoxib alone, even though these particles did not affect the degree of migration or COX-2 expression in the tumor cells. Keywords: celecoxib, cyclo-oxygenase-2, PLGA nanoparticles, glioma, antitumor activit

Rapid quantification of DNA methylation through dNMP analysis following bisulfite-PCR

We report a novel method for rapid quantification of the degree of DNA methylation of a specific gene. Our method combined bisulfite-mediated PCR and quantification of deoxyribonucleoside monophosphate (dNMP) contents in the PCR product through capillary electrophoresis. A specific bisulfite-PCR product was enzymatically hydrolyzed to dNMP monomers which were quantitatively analyzed through subsequent capillary electrophoresis. PCR following bisulfite treatment converts unmethylated cytosines to thymines while leaving methyl-cytosines unchanged. Then the ratio of cytosine to thymine determined by capillary electrophoresis represents the ratio of methyl-cytosine to cytosine in genomic locus of interest. Pure oligonucleotides with known sequences were processed in parallel as standards for normalization of dNMP peaks in capillary electrophoresis. Sources of quantification uncertainty such as carryovers of dNTPs or primers and incomplete hydrolysis were examined and ruled out. When the method was applied to samples with known methylation levels (by bisulfite-mediated sequencing) as a validation, deviations were within ±5%. After bisulfite-PCR, the analytical procedure can be completed within 1.5 h

Crystallization and preliminary X-ray crystallographic studies of the ice-binding protein from the Antarctic yeast Leucosporidium sp. AY30. Corrigendum

A correction to the article by Park et al. [(2011). Acta Cryst. F67, 800–802]