Sung-Woon Cho

Gabapentin reduces rectal mechanosensitivity and increases rectal compliance in patients with diarrhoea‐predominant irritable bowel syndrome

Background : Gabapentin has been shown to reduce elements of central sensitization in human experimental hyperalgesia. It remains uninvestigated whether gabapentin has beneficial effects for irritable bowel syndrome associated with visceral hypersensitivity.

Effect of virological response on post-treatment durability of lamivudine-induced HBeAg seroconversion.

Lamivudine‐induced HBeAg seroconversion may not be durable in Korean patients with hepatitis B virus (HBV) infection. It is unknown whether virological response during lamivudine treatment affects the post‐treatment outcome. We retrospectively analysed 124 consecutive HBeAg‐positive chronic hepatitis B (CHB) patients treated with lamivudine. Lamivudine was given at a dose of 100 mg per day. HBV DNA levels in sera obtained before and during therapy were measured by the Digene Hybrid Capture II assay and Digene Ultrasensitive Hybrid Capture II assay, respectively. HBeAg seroconversion was achieved in 42 of the 124 patients (33.8%) treated with lamivudine. Mean duration of treatment in HBeAg seroconverters was 12.86 ± 4.44 months. During the follow‐up period, the cumulative relapse rates at 3 months and 6 months post‐treatment in 42 patients with HBeAg seroconversion were 40.5% and 57.4%, respectively. Among 31 seroconverted patients whose sera were available at the second month of treatment, HBV DNA remained at > 4.7 × 103 genomes/mL in 15 patients and decreased to < 4.7 × 103 genomes/mL in the remaining 16 patients. HBV DNA levels at the second month of treatment was not related with relapse after discontinuation of treatment (66.7% vs. 43.8%, P= 0.2). At the time of HBeAg seroconversion, HBV DNA remained at > 4.7 × 103 genomes/mL in five patients and decreased to < 4.7 × 103 genomes/mL in the remaining 37 patients. Relapse rates were increased in patients who remained at > 4.7 × 103 genomes/mL compared with patients with HBV DNA levels < 4.7 × 103 genomes/mL (100% vs. 51.4%, P < 0.001). Thus, monitoring of serum HBV DNA at the time of HBeAg seroconversion may be helpful for predicting relapse in patients with lamivudine‐induced HBeAg seroconversion.

Factors that affect the diagnostic accuracy of liver fibrosis measurement by Fibroscan in patients with chronic hepatitis B

Aliment Pharmacol Ther 2010; 32: 498–505

Low efficacy of entecavir therapy in adefovir-refractory hepatitis B patients with prior lamivudine resistance

Summary.  We determined the virologic response, incidence of entecavir resistance, and evolution of lamivudine and adefovir‐resistant mutants during entecavir (ETV) therapy in adefovir‐refractory patients with prior lamivudine resistance. Forty adefovir‐refractory chronic hepatitis B patients with prior lamivudine resistance who had received entecavir for ≥6 months were included and monitored for virologic response and entecavir resistance. Ten per cent of patients achieved HBV DNA < 50 copies/mL by PCR after 24 weeks of ETV therapy, and an initial virologic response was observed in 12 of 40 patients (30%). Higher pretreatment ALT (P = 0.039) and the presence of the rtL180M mutation (P = 0.038) were associated with an initial virologic response. During a mean follow‐up of 11.4 months, four patients (10%) experienced virologic breakthrough, while ETV‐resistant mutants were detected in six patients (15%). YMDD and adefovir‐resistant mutants were detected in 57 and 35% of patients at baseline, respectively. At 48 weeks of therapy, 96 and 4% of patients had YMDD and adefovir‐resistant mutants, respectively. These data suggest an early development of ETV resistance and low antiviral response during ETV therapy in adefovir‐refractory patients with prior lamivudine resistance.

Effect of long-term administration of rebamipide on Helicobacter pylori infection in mice.

Background : It has been suggested that chronic, persistent, uncontrolled inflammations in the stomach could provide the basic step for the beginning of carcinogenesis. One of the potential clinical applications of rebamipide is the inhibition of the immunoinflammatory response in gastric mucosa imposed by Helicobacter pylori.

Association of a microRNA-323b polymorphism with the persistence of hepatitis B virus infection by the enhancement of viral replication

Recent studies have shown that some mammalian microRNAs (miRNAs) play a role in antiviral defence. However, little is known about the role of miRNA‐323b in hepatitis B virus (HBV)‐host interaction. We explored whether single nucleotide polymorphism (SNP) of miRNA‐323b affects HBV replication in a Korean HBV cohort. Genotyping was performed in a total of 1439 subjects composed of 404 spontaneously recovered (SR) subjects as normal controls and 1035 chronic carriers (CC) of HBV who were further classified into 313 patients with chronic hepatitis, 305 patients with liver cirrhosis and 417 patients with hepatocellular carcinoma. To confirm the effect of SNP of miRNA‐323b on HBV replication in vitro, HepAD38 cells were transfected with miRNA‐323b wild type or miRNA‐323b SNP plasmid vectors, and HBV replication was induced for 5 days. HBV DNA was isolated and quantified using real‐time PCR. The polymorphism rs56103835C>T in the pre‐miRNA region of miRNA‐323b revealed significant minor allele frequency (0.273). rs56103835C>T SNP showed significantly affect persistence of HBV in CC group compared with SR group (OR = 1.29, P = 0.009 in a codominant model; OR = 1.29, P = 0.03 in a dominant model; and OR = 1.78, P = 0.03 in a recessive model). In vitro, the total intracellular HBV DNA content was significantly reduced by miRNA‐323b wild‐type plasmid vector transfection (P = 0.014). The polymorphism of miRNA‐323b was significantly associated with persistence of HBV by the enhancement of HBV replication (P = 0.021). Our findings provide a novel perspective on the role SNP of miRNAs in host–virus interactions in HBV infection.

Angular dependences of SiO2 etch rates in C4F6/O2/Ar and C4F6/CH2F2/O2/Ar plasmas

The angular dependences of SiO2 etch rates for C4F6/O2/Ar and C4F6/CH2F2/O2/Ar plasmas were investigated using a Faraday cage system. In the absence of CH2F2, the steady-state fluorocarbon film that formed on the SiO2 surface was thin enough (<10 A) for ions to penetrate through the film. The normalized etch yield (NEY) curve in this case showed a maximum value of 1.74 at an ion-incident angle of 70°, illustrating that physical sputtering was a major contributor to the SiO2 etching. The addition of CH2F2 to C4F6/O2/Ar plasmas produced thicker and more etch-resistant fluorocarbon films, leading to a decrease in the ion energy transfer depth through the steady-state films. This implies that physical sputtering was suppressed when CH2F2 was present in the plasma, demonstrated by a decrease in the maximum NEY and the ion-incident angle at the maximum NEY.

Fabrication of Slanted Cu Nanopillars with Uniform Arrays

Slanted Cu nanopillars with uniform arrays were fabricated using slanted Si channel structures as templates. A slanted plasma etching technique was employed, utilizing a Faraday cage system for the formation of these slanted channel structures. The angle of the slanted channel structures was accurately controlled because ions entering the Faraday cage maintained their direction. After the slanted channel structures were formed, they were filled with Cu by electroless deposition. Chemical mechanical polishing was then used to remove the excess Cu film and the SiO2 masks. Finally, the remaining poly Si of the channel structures was removed by wet chemical etching. This work offers a novel method for the fabrication of slanted metal nanostructures with uniform arrays covering a large area.

Angular dependences of Si 3 N 4 etch rates and SiO 2 -to-Si 3 N 4 etch selectivity in C 4 F 6 /Ar/O 2 /CH 2 F 2 plasmas

Si<inf>3</inf>N<inf>4</inf> films are usually used as a protecting layer of a poly silicon gate during the etching of a contact hole. An increase in the etch rates of Si<inf>3</inf>N<inf>4</inf> at its curved surface lowers the etch selectivity of SiO<inf>2</inf> with respect to Si<inf>3</inf>N<inf>4</inf> [1, 2], resulting in device failure. Therefore, it is important to control the angular dependence of Si<inf>3</inf>N<inf>4</inf> etch rates and SiO<inf>2</inf>-to-Si<inf>3</inf>N<inf>4</inf> etch selectivity. In this work, the angular dependences of the Si<inf>3</inf>N<inf>4</inf> etch rate and SiO<inf>2</inf>-to-Si<inf>3</inf>N<inf>4</inf> etch selectivity in a C<inf>4</inf>F<inf>6</inf>/Ar/O<inf>2</inf>/CH<inf>2</inf>F<inf>2</inf> plasma were investigated using a speciallydesigned Faraday cage system. The Faraday cage allowed one to control the ion-incident angles. Etching was conducted by varying the ratio of CH<inf>2</inf>F<inf>2</inf> flow rate to study a role of steadystate fluorocarbon films formed on the surface of the Si<inf>3</inf>N<inf>4</inf> substrate during etching.