Intrahospital transmission and infection control of Candida auris originating from a severely infected COVID-19 patient transferred abroad

BACKGROUND

Intrahospital spread of Candida auris, which survives tenaciously in many environments, can cause sustained colonization and infection. A large outbreak of C. auris was experienced in the intensive care units (ICUs) at the study hospital during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

The index patient with severe COVID-19, who was transferred from Vietnam in January 2022, developed C. auris candidaemia 10 days after hospitalization. From mid-June 2022 to January 2023, strengthened infection prevention and control (IPC) measures were implemented in three ICUs: (1) contact precautions and isolation (CPI) for C. auris-positive cases; (2) surveillance cultures including point-prevalence (N=718) for patients or close contacts or ICU-resident healthcare workers (HCWs); (3) intensive environmental disinfection with 10-fold diluted bleach; and (4) 2% chlorhexidine bathing for all ICU patients. Environmental cultures (ECx) on surfaces and shared objects (N=276) were conducted until early September 2022, when all ECx were negative.

RESULTS

Among 53 C. auris-positive patients between February 2022 and January 2023, invasive infections resulted in seven cases of candidaemia and one case of pneumonia. C. auris was isolated from reusable tympanic thermometers (TTMs) contaminated with earwax. The isolation rate of C. auris in ECx decreased from 6.8% in June 2022 to 2.0% in August 2022, and was no longer detected in TTMs. Colonization in HCWs was remarkably rare (0.5%). The number of C. auris-positive patients peaked in July (N=10) then decreased gradually. By January 2023, no C. auris were isolated in the ICU.

CONCLUSION

Aggressive IPC measures with CPI, ECx and surveillance, decontamination of TTMs, and bathing were effective in successfully controlling this C. auris outbreak.

Initial phase establishment of an in vitro method for developmental neurotoxicity test using Ki-67 in human neural progenitor cells

Building a precise alternative neurotoxicological test is of great importance to respond to societal and ethical requirements. In this study, a new developmental neurotoxicity test (DNT) was established with the human neural progenitor cell line. ReNcell CX cells were exposed to neurotoxic chemicals (aphidicolin, hydroxyurea, cytosine arabinoside, 5-fluorouracil, and ochratoxin A) or non-neurotoxic chemicals (sodium gluconate, sodium bicarbonate, penicillin G, and saccharin). Propidium iodide (PI) was used to evaluate cell viability. BrdU and Ki-76 were employed to determine cell proliferation. Based on the cell viability and proliferation, mathematical models were built by linear discriminant analysis. Furthermore, the neurotoxic-considered chemicals inhibited cell cycle progression at the protein level, supporting the biomolecular rationale for the predictive model. Overall, these results show that the new test method can be used to determine the potential developmental neurotoxicants or new drug candidates.

Analysis of Hepatitis C Virus Resistance-Associated Substitutions in Direct-Acting Antiviral Failure in South Korea Using Next-Generation Sequencing

Background/Aims

We analyzed resistance-associated substitutions (RAS) and retreatment outcomes in patients with chronic hepatitis C virus (HCV) infection who failed direct-acting antiviral agent (DAA) treatment in South Korea using next-generation sequencing (NGS).

Methods

Using prospectively collected data from the Korea HCV cohort study, 36 patients who failed DAA treatment were recruited from 10 centers between 2007 and 2020; 29 blood samples were available from 24 patients. RASs were analyzed using NGS.

Results

RAS was analyzed for 13 patients with genotype 1b, ten with genotype 2, and one with genotype 3a. The unsuccessful DAA regimens were daclatasvir+asunaprevir (n=11), sofosbuvir+ribavirin (n=9), ledipasvir/sofosbuvir (n=3), and glecaprevir/pibrentasvir (n=1). In patients with genotype 1b, NS3, NS5A, and NS5B RASs were detected in eight, seven, and seven out of ten patients at baseline and in four, six, and two out of six patients after DAA failure, respectively. Among ten patients with genotype 2, the only baseline RAS was NS3 Y56F, detected in one patient. NS5A F28C was detected after DAA failure in a patient with genotype 2 infection erroneously treated with daclatasvir+asunaprevir. After retreatment 16 patients had a 100% sustained virological response rate.

Conclusions

NS3 and NS5A RASs were commonly present at baseline, and there was an increasing trend of NS5A RAS after failed DAA treatment in genotype 1b. However, RAS was rarely present in patients with genotype 2 treated with sofosbuvir plus ribavirin. Despite baseline or treatment-emergent RAS, retreatment with pan-genotypic DAA was highly successful in Korea, encouraging active retreatment for unsuccessful DAA treatment.

Effectiveness of 4-Week Oral Taurine Treatment for Muscle Cramps in Patients with Liver Cirrhosis: A Single-Arm Pilot Study

PURPOSE

Painful muscle cramps are a common complication in liver cirrhosis patients, and no effective treatment is available. This pilot study aimed to evaluate whether taurine supplementation improves muscle cramps in Korean cirrhotic patients.

MATERIALS AND METHODS

Ten cirrhotic patients who experienced muscle cramps one or more times/week were enrolled in this prospective single-arm study and administered with an oral taurine solution (1 g/50 mL) thrice a day for 4 weeks. Taurine was discontinued for the subsequent 4 weeks. The frequency and intensity of muscle cramps were evaluated using a questionnaire at weeks 0, 2, 4, 6, and 8 after the start of treatment.

RESULTS

At baseline, the median frequency of muscle cramps was six times/week, and all patients had severe pain. Muscle cramp scores (frequency×intensity) decreased in seven patients by weeks 4 and 8 after treatment initiation. Compared to baseline muscle cramp scores [median 21, interquartile range (IQR): 8-84], median muscle cramp scores were lower at week 4 (6.5, IQR: 3-12, p=0.126) and week 8 (5, IQR: 1.5-56, p=0.066). All five patients whose baseline plasma taurine levels were below the normal limit showed increased taurine levels at week 4; 60% of them experienced improvements in their muscle cramps. Of the five patients with normal or higher taurine levels, 80% experienced an improvement in symptoms at week 4. The safety and tolerability of the 4-week taurine therapy were excellent.

CONCLUSION

Oral taurine therapy for 4 weeks improved muscle cramps safely in cirrhotic patients.

A Case of Autoimmune Hepatitis after Occupational Exposure to N,N-Dimethylformamide

N,N-dimethylformamide (DMF), a widely used solvent in the chemical industry, is known to induce toxic hepatitis. However, there have been no reported cases of DMF-associated autoimmune hepatitis. A 31-year-old healthy man working at a glove factory since July 2015 had intermittently put his bare hands into a diluted DMF solution for his first 15 days at work. After 2 months, he felt nausea, fatigue, and hand cramping, and a jaundice followed. His laboratory findings showed positive autoantibodies and elevated immunoglobulin G (IgG), and his liver biopsy pathology was typical of autoimmune hepatitis (AIH). Prednisolone and azathioprine therapy began, and he recovered rapidly without adverse events. Though his liver chemistry was normalized, the IgG level remained persistently upper normal range. His 2nd liver biopsy performed in April 2019 showed mild portal activity, and he was well under a low dose immunosuppressive therapy up to April 2020. This case warns of the hazard of occupational exposure to DMF, and clinicians should be aware of DMF-related AIH for timely initiation of immunosuppressive therapy.

Clinical features and prognosis of patients with idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease

<sec> <title>BACKGROUND</title> Idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) share common risk factors. They could therefore be expressed in a single patient. However, the prevalence, clinical characteristics and prognosis of individuals with comorbid IPF and COPD are not known. </sec> <sec> <title>METHOD</title> From 2003 to 2007, the Korean Interstitial Lung Disease Study Group created a register for idiopathic interstitial pneumonia using 2002 ATS/ERS (American Thoracic Society/European Respiratory Society) criteria. Of the 1546 IPF patients assessed, 143 had decreased lung function consistent with COPD (IPF-COPD). COPD was diagnosed based on age (≥40 years) and pulmonary function (forced expiratory volume in 1 sec [FEV₁]/forced vital capacity [FVC] ratio < 0.7). </sec> <sec> <title>RESULTS</title> The median age of the IPF-COPD group was 71.0 years (interquartile range 66.0-76.0); most patients were male (88.1%). FVC (%) was significantly higher in the IPF-COPD group; however, FEV₁ (%) was significantly lower in the IPF-COPD group (P < 0.001). Diffusing capacity of the lung for carbon monoxide (DL_CO) was not significantly different between the two groups. In survival analysis, age and FVC (%), but not COPD, were significantly associated with prognosis (respectively P = 0.003, 0.001 and 0.401). COPD severity was also not related to prognosis (P = 0.935). </sec> <sec> <title>CONCLUSION</title> The prevalence of IPF-COPD was estimated to be ∼9.2% among all IPF patients; prognosis of patients with IPF-COPD was not worse than those with IPF alone. </sec>.

Silver nanoparticles induce Egr-1-dependent psoriasin expression via the ERK and p38 pathways

BACKGROUND

Silver nanoparticles (Ag-NPs) can prevent bacterial infection and improve cutaneous wound healing owing to their antimicrobial activity. However, the mechanism of their antimicrobial activity is poorly understood.

AIM

To determine the mechanistic relationship between Ag-NP treatment and expression of psoriasin.

METHODS

Human epidermal keratinocytes, neonatal (HEKn) were used. Psoriasin mRNA expression was measured by reverse transcription PCR and real-time PCR. Western blotting was performed to verify expression of early growth response-1 (Egr-1) and psoriasin, and phosphorylation of mitogen-activated protein kinase (MAPK). Psoriasin promoter activity by Egr-1 was detected by a luciferase assay.

RESULTS

Treatment of HEKn with Ag-NPs induced psoriasin mRNA and protein expression. Upregulation of psoriasin promoter activity was also observed in the luciferase assay. Ag-NPs increased Egr-1 expression, promoter activity and nuclear translocation in HEKn. Psoriasin luciferase activity was increased in HEKn transfected with Egr-1 pcDNA 3.1. Ag-NPs activated MAPK pathways including the extracellular signal-regulated kinase (ERK), p38, and c-Jun-N-terminal kinase (JNK) pathways. The upregulation of Egr-1 expression by Ag-NP stimulation was inhibited by ERK and p38 inhibitors, but not by a JNK inhibitor. Psoriasin expression was reduced in Egr-1 small interfering RNA-transfected HEKn.

CONCLUSIONS

Ag-NP treatment induces upregulation of psoriasin expression through Egr-1 expression. We suggest that the ERK and p38 pathways are involved in Egr-1-dependent psoriasin expression.

Acute endophthalmitis after cataract surgery: 164 consecutive cases treated at a referral center in South Korea

PurposeTo identify prognostic factors in patients referred with endophthalmitis after cataract surgery, and to evaluate the efficacy of primary vitrectomy as an initial management.MethodsOver an eight-year study period, we retrospectively reviewed the medical records of 164 patients who were referred with endophthalmitis following cataract surgery. Treatment generally conformed to standard guidelines, although primary vitrectomy was performed in several eyes with a visual acuity of hand motion or better, depending on the patient's status. Using multivariate analysis, we analyzed outcomes to determine the effect on final visual outcome.ResultsA final visual acuity of ≥20/40 was achieved in 92/164 (56.1%) cases after treatment. Bacterial cultures showed bacterial growth in 89/164 cases (54.3%). Among the various baseline characteristics, old age (P=0.028), poor visual acuity at presentation (P=0.004), gram-negative bacterial infection (P=0.030), and short time between cataract surgery and signs of endophthalmitis (P=0.021) were associated with poor visual outcome. The visual outcome showed no significant difference, in terms of initial treatment feature, between the primary vitrectomy with intraocular antibiotics injection (IOAI) and IOAI-only groups. However, reintervention was significantly less frequent in the primary vitrectomy group than in the IOAI group (12.5 and 32.7%, respectively; P=0.002).ConclusionOld age, poor visual acuity at presentation, type of cultured organism (gram-negative bacteria), and early onset of endophthalmitis after cataract surgery were significantly related to poor visual outcome after endophthalmitis treatment. Primary vitrectomy may decrease the need for reintervention to control infection, although the treatment showed no benefits with regard to visual outcome.

A phase 3b study of sofosbuvir plus ribavirin in treatment-naive and treatment-experienced Korean patients chronically infected with genotype 2 hepatitis C virus

In Korea, patients with chronic hepatitis C virus (HCV) infection are typically treated with pegylated interferon-alpha plus ribavirin, but interferons are contraindicated in many patients and are often poorly tolerated, particularly by the elderly and those with advanced liver disease. No interferon-free treatment regimens are approved in Korea. Sofosbuvir is an oral nucleotide analog inhibitor of the HCV nonstructural 5B RNA polymerase. It is approved in the USA, European Union and Japan for treating a number of HCV genotypes, including genotype 2. Genotype 2 has a seroprevalence of 38-46% in Korea. This single-arm, phase 3b study (NCT02021643) examined the efficacy and safety of sofosbuvir plus ribavirin (12-week duration) in chronic genotype 2 HCV-infected treatment-naive and treatment-experienced Korean patients with and without cirrhosis. The proportion of patients with sustained virologic response 12 weeks after treatment discontinuation (SVR12) was 97% (125/129), with 96% (101/105) of treatment-naive and 100% (24/24) of treatment-experienced patients achieving SVR12. Two patients experienced virologic failure (n = 1, on-treatment failure; n = 1, relapse). No patient discontinued study treatment due to an adverse event (AE). The most common treatment-emergent AEs were headache (18%, 23/129) and pruritus (15%, 19/129). Few patients had grade 3 AEs (5%, 6/129) or grade 3 laboratory abnormalities (12%, 15/129). No grade 4 AE was reported. These data suggest that 12 weeks of treatment with the all-oral, interferon-free regimen of sofosbuvir plus ribavirin is effective and well tolerated in Korean patients with chronic genotype 2 HCV infection.

Modification to the accelerator of the NBI-1B ion source for improving the injection efficiency

Minimizing power loss of a neutral beam imposes modification of the accelerator of the ion source for further improvement of the beam optics. The beam optics can be improved by focusing beamlets. The injection efficiencies by the steering of ion beamlets are investigated numerically to find the optimum modification of the accelerator design of the NBI-1B ion source. The beam power loss was reduced by aperture displacement of three edge beamlets arrays considering power loadings on the beamline components. Successful testing and operation of the ion source at 60 keV/84% of injection efficiency led to the possibility of enhancing the system capability to a 2.4 MW power level at 100 keV/1.9 μP.

Role of protein kinase C-η in cigarette smoke extract-induced apoptosis in MRC-5-cells

Cigarette smoke (CS) is a major risk factor for emphysema, which causes cell death in structural cells of the lung by mechanisms that are still not completely understood. We demonstrated previously that CS extract (CSE) induces caspase activation in MRC-5 human lung fibroblasts, activated protein kinase C-η (PKC-η), and translocated PKC-η from the cytosol to the membrane. The objective of this study was to investigate the involvement of PKC-η activation in a CSE-induced extrinsic apoptotic pathway. We determined that CSE increases expression of caspase 3 and 8 cleavage in MRC-5 cells and overexpression of PKC-η significantly increased expression of caspase 3 and 8 cleavage compared with control LacZ-infected cells. In contrast, dominant negative (dn) PKC-η inhibited apoptosis in MRC-5 cells exposed to CSE and decreased expression of caspase 3 and 8 compared with control cells. Exposure to 10% CSE for >8 h significantly increased lactate dehydrogenase release in PKC-η-infected cells compared with LacZ-infected cells. Additionally, PKC-η-infected cells had an increased number of Hoechst 33342 stained nuclei compared with LacZ-infected cells, while dn PKC-η-infected cells exhibited fewer morphological changes than LacZ-infected cells under phase-contrast microscopy. In conclusion, PKC-η activation plays a pro-apoptotic role in CSE-induced extrinsic apoptotic pathway in MRC-5 cells. These results suggest that modulation of PKC-η may be a useful tool for regulating the extrinsic apoptosis of MRC-5 cells by CSE and may have therapeutic potential in the treatment of CS-induced lung injury.

Analysis of RAS mutation and PAX8/PPARγ rearrangements in follicular-derived thyroid neoplasms in a Korean population: frequency and ultrasound findings

OBJECTIVE

To investigate the frequency and ultrasonography (US) findings of RAS mutations and PAX8/PPARγ rearrangements between follicular thyroid adenomas (FTAs) and follicular thyroid carcinomas (FTCs) in a Korean population.

METHODS

RAS mutations and PAX8/PPARγ rearrangements in 56 FTAs and 35 FTCs were analyzed. We also analyzed the US findings of FTCs and FTAs.

RESULTS

16 nodules of 35 FTCs (45.7 %) and 19 nodules of 56 FTAs (33.9 %) harbored RAS mutations. Three FTCs and three FTAs showed two point mutations simultaneously. K-RAS codon 12-13 (n = 6, 31.6 %), N-RAS codon 61 (n = 5, 26.3 %), H-RAS codon 61 (n = 4, 21.1 %), K-RAS codon 61 (n = 3, 15.8 %), and N-RAS codon 12-13 (n = 1, 5.3 %) were found in FTCs, and N-RAS codon 61 (n = 10, 45 %), K-RAS codon 12-13 (n = 5, 22.7 %), H-RAS codon 61 (n = 5, 22.7 %), K-RAS codon 61 (n = 1, 4.5 %), and N-RAS codon 12-13 (n = 1, 4.5 %) were observed in FTAs. 4 of 56 (7.1 %) FTAs and 1 of 35 (2.9 %) FTCs represented PAX8/PPARγ rearrangements, respectively (P = 0.645). The absence of a hypoechoic rim (P = 0.021) and presence of calcifications (P = 0.049) were significantly associated with FTCs compared with FTAs.

CONCLUSIONS

RAS mutation frequency targeting the Korean population showed a 45.7 % in FTCs and 35.7 % in FTAs, and PAX8/PPARγ rearrangements were more frequently showed in FTAs. K-RAS codon 12-13 was the most common RAS mutation in FTCs, whereas N-RAS codon 61 was more frequent in FTAs. The presence of calcifications and absence of a hypoechoic rim showed more frequently in FTCs.

Safety and immunogenicity of therapeutic DNA vaccine with antiviral drug in chronic HBV patients and its immunogenicity in mice

BACKGROUND & AIMS

Here, we evaluated the safety and immunogenicity of hepatitis B virus (HBV) DNA vaccine, HB-110, in mice and Korean patients with chronic hepatitis B (CHB) undergoing adefovir dipivoxil (ADV) treatment.

METHODS

For animal study, mice (BALB/c or HBV transgenic) were immunized with mHB-110, and T-cell and antibody responses were evaluated. For clinical study, 27 patients randomly received either ADV alone or ADV in combination with HB-110. Liver function tests, serum HBV DNA levels and the presence of HBeAg/anti-HBe were analysed. T-cell responses were estimated by ELISPOT and FACS analysis.

RESULTS

mHB-110 induced higher T-cell and antibody responses than mHB-100 in mice. No adverse effects were observed by HB-110 cotreated with ADV. HBV-specific T-cell responses were induced in a portion of patients in medium to high dose of HB-110. Interestingly, HB-110 exhibited positive effects on ALT normalization and maintenance of HBeAg seroconversion. One patient, who received high dose of HB-110 exhibited HBeAg seroconversion during vaccination, which correlated with vaccine-induced T-cell responses without ALT elevation.

CONCLUSIONS

HB-110 was safe and tolerable in CHB patients. In contrast to results in animal models, HB-110 in Korean patients exhibited weaker capability of inducing HBV-specific T-cell responses and HBeAg seroconversion than HB-100 in Caucasian patients. As Asian patients, who are generally infected via vertical transmission, appeared to have higher level of immune tolerance than Caucasian, novel approaches for breaking immune tolerance rather than enhancing immunogenicity may be more urgently demanded to develop effective therapeutic HBV DNA vaccines.

The efficacy of moxifloxacin-containing triple therapy after standard triple, sequential, or concomitant therapy failure for Helicobacter pylori eradication in Korea

Background/Aims

Retreatment after initial treatment failure for Helicobacter pylori is very challenging. The purpose of this study was to evaluate the efficacies of moxifloxacin-containing triple and bismuth-containing quadruple therapy.

Methods

A total of 151 patients, who failed initial H. pylori treatment, were included in this retrospective cohort study. The initial regimens were standard triple, sequential, or concomitant therapy, and the efficacies of the two following second-line treatments were evaluated: 7-day moxifloxacin-containing triple therapy (rabeprazole 20 mg twice a day, amoxicillin 1,000 mg twice a day, and moxifloxacin 400 mg once daily) and 7-day bismuth-containing quadruple therapy (rabeprazole 20 mg twice a day, tetracycline 500 mg 4 times a day, metronidazole 500 mg 3 times a day, and tripotassium dicitrate bismuthate 300 mg 4 times a day).

Results

The overall eradication rates after moxifloxacin-containing triple therapy and bismuth-containing quadruple therapy were 69/110 (62.7%) and 32/41 (78%), respectively. Comparison of the two regimens was performed in the patients who failed standard triple therapy, and the results revealed eradication rates of 14/28 (50%) and 32/41 (78%), respectively (p=0.015). The frequency of noncompliance was not different between the two groups, and there were fewer adverse effects in the moxifloxacin-containing triple therapy group (2.8% vs 7.3%, p=0.204 and 25.7% vs 43.9%, p=0.031, respectively).

Conclusions

Moxifloxacin-containing triple therapy, a recommended second-line treatment for initial concomitant or sequential therapy failure, had insufficient efficacy.

Comparison of the effects of normal saline versus Plasmalyte on acid-base balance during living donor kidney transplantation using the Stewart and base excess methods

BACKGROUND

Ischemia-reperfusion injury is an inevitable consequence of kidney transplantation, leading to metabolic acidosis. This study compared the effects of normal saline (NS) and Plasmalyte on acid-base balance and electrolytes during living donor kidney transplantation using the Stewart and base excess (BE) methods.

METHODS

Patients were randomized to an NS group (n = 30) or a Plasmalyte group (n = 30). Arterial blood samples were collected for acid-base analysis after induction of anesthesia (T0), prior to clamping the iliac vein (T1), 10 minutes after reperfusion of the donated kidney (T2), and at the end of surgery (T3). In addition serum creatinine and 24-hour urine output were recorded on postoperative days 1,2, and 7. Over the first postoperative 7 days we recorded episodes of graft failure requiring dialysis.

RESULTS

Compared with the Plasmalyte group, the NS group showed significantly lower values of pH, BE, and effective strong ion differences during the postreperfusion period (T2 and T3). Chloride-related values (chloride [Cl(-)], free-water corrected Cl(-), BEcl) were significantly higher at T1, T2, and T3, indicating hyperchloremic rather than dilutional metabolic acidosis. Early postoperative graft functions in terms of serum creatinine, urine output, and graft failure requiring dialysis were not significantly different between the groups.

CONCLUSIONS

Both NS and Plamalyte can be used safely during uncomplicated living donor kidney transplantation. However, Plasmalyte more stably maintains acid-base and electrolyte balance compared with NS especially during the postreperfusion period.

Clinical characteristics and outcomes of acute hepatitis a in Korea: a nationwide multicenter study

The aim of this study was to investigate the clinical characteristics of acute hepatitis A during a recent outbreak in Korea. Data of patients diagnosed with acute hepatitis A from 2007 to 2009 were collected from 21 tertiary hospitals retrospectively. Their demographic, clinical, and serological characteristics and their clinical outcomes were analyzed. A total of 4,218 patients (mean age 33.3 yr) were included. The median duration of admission was 9 days. The mean of the highest ALT level was 2,963 IU/L, total bilirubin was 7.3 mg/dL, prothrombin time INR was 1.3. HBsAg was positive in 3.7%, and anti-HCV positive in 0.7%. Renal insufficiency occurred in 2.7%, hepatic failure in 0.9%, relapsing hepatitis in 0.7%, and cholestatic hepatitis in 1.9% of the patients. Nineteen patients (0.45%) died or were transplanted. Complications of renal failure or prolonged cholestasis were more frequent in patients older than 30 yr. In conclusion, most patients with acute hepatitis A recover uneventfully, however, complication rates are higher in patients older than 30 yr than younger patients. Preventive strategies including universal vaccination in infants and active immunization of hepatitis A to adult population should be considered for prevention of community-wide outbreaks of hepatitis A in Korea.

Development progresses of radio frequency ion source for neutral beam injector in fusion devices

A large-area RF (radio frequency)-driven ion source is being developed in Germany for the heating and current drive of an ITER device. Negative hydrogen ion sources are the major components of neutral beam injection systems in future large-scale fusion experiments such as ITER and DEMO. RF ion sources for the production of positive hydrogen (deuterium) ions have been successfully developed for the neutral beam heating systems at IPP (Max-Planck-Institute for Plasma Physics) in Germany. The first long-pulse ion source has been developed successfully with a magnetic bucket plasma generator including a filament heating structure for the first NBI system of the KSTAR tokamak. There is a development plan for an RF ion source at KAERI to extract the positive ions, which can be applied for the KSTAR NBI system and to extract the negative ions for future fusion devices such as the Fusion Neutron Source and Korea-DEMO. The characteristics of RF-driven plasmas and the uniformity of the plasma parameters in the test-RF ion source were investigated initially using an electrostatic probe.

Improvement of a plasma uniformity of the 2nd ion source of KSTAR neutral beam injector

The 2nd ion source of KSTAR (Korea Superconducting Tokamak Advanced Research) NBI (Neutral Beam Injector) had been developed and operated since last year. A calorimetric analysis revealed that the heat load of the back plate of the ion source is relatively higher than that of the 1st ion source of KSTAR NBI. The spatial plasma uniformity of the ion source is not good. Therefore, we intended to identify factors affecting the uniformity of a plasma density and improve it. We estimated the effects of a direction of filament current and a magnetic field configuration of the plasma generator on the plasma uniformity. We also verified that the operation conditions of an ion source could change a uniformity of the plasma density of an ion source.

Telomere length, TERT and shelterin complex proteins in hepatocellular carcinomas expressing "stemness"-related markers

BACKGROUND & AIMS

Hepatocellular carcinomas (HCCs) expressing "stemness"-related markers have been associated with aggressive biological behavior and poor prognosis. We examined the relationship between "stemness"-related protein expression and telomere length, hTERT and shelterin complex protein expression and chromosomal instability.

METHODS

Quantitative fluorescent in situ hybridization for telomere length, immunohistochemistry for K19, EpCAM, CD133, c-kit, HepPar1, hTERT, TRF1, TRF2, POT1, RAP1 and TPP1, and TUNEL assay were performed in 137 HCCs, and array comparative genomic hybridization was performed with 24 HCCs.

RESULTS

Telomeres were significantly longer in HCCs expressing "stemness"-related proteins (K19: p < 0.001, EpCAM: p = 0.002, CD133: p = 0.002). On analyzing different tumor cells within EpCAM-expressing HCCs, EpCAM-positive tumor cells showed longer telomeres (1.329 ± 0.246) compared to EpCAM-negative tumor cells (0.996 ± 0.381) within the same HCCs (p = 0.031). Telomeres were significantly longer in HCCs expressing hTERT (p = 0.048) and RAP1 proteins (p = 0.031). K19-expressing HCCs expressed hTERT (p = 0.002), TRF2 (p = 0.001) and TPP1 (p = 0.013) more frequently compared to K19-negative HCCs. EpCAM-positivity was associated with more frequent hTERT (p = 0.028), TPP1 (p = 0.017), TRF2 (p = 0.027) and POT1 (p = 0.004) expression. Copy number alterations were more frequent in K19 and EpCAM-expressing HCCs compared to HCCs without these markers (K19: p = 0.038, EpCAM: p = 0.009). HCCs with longer telomeres were associated with a shorter overall (p = 0.019) and disease-free survivals (p = 0.049), and decreased disease-free survivals were seen in TRF2-positive HCCs (p = 0.018).

CONCLUSIONS

HCCs expressing "stemness"-related proteins are characterized by increased telomere length, increased expression of hTERT and shelterin complex proteins, and increased chromosomal instability compared to conventional HCCs. Longer telomeres and TRF2 expression in HCCs are associated with poor patient outcomes.

Mitochondrial modulation decreases the bortezomib-resistance in multiple myeloma cells

Multiple myeloma (MM) is an incurable hematological malignancy that causes most patients to eventually relapse and die from their disease. The 20S proteasome inhibitor bortezomib has emerged as an effective drug for MM treatment; however, intrinsic and acquired resistance to bortezomib has already been observed in MM patients. We evaluated the involvement of mitochondria in resistance to bortezomib-induced cell death in two different MM cell lines (bortezomib-resistant KMS20 cells and bortezomib-sensitive KMS28BM cells). Indices of mitochondrial function, including membrane potential, oxygen consumption rate and adenosine-5'-triphosphate and mitochondrial Ca(2+) concentrations, were positively correlated with drug resistance of KMS cell lines. Mitochondrial genes including CYPD, SOD2 and MCU were differentially expressed in KMS cells. Thus, changes in the expression of these genes lead to changes in mitochondrial activity and in bortezomib susceptibility or resistance, and their combined effect contributes to differential sensitivity or resistance of MM cells to bortezomib. In support of this finding, coadministration of bortezomib and 2-methoxyestradiol, a SOD inhibitor, rendered KMS20 cells sensitive to apoptosis. Our results provide new insight into therapeutic modalities for MM patients. Studying mitochondrial activity and specific mitochondrial gene expression in fresh MM specimens might help predict resistance to proapoptotic chemotherapies and inform clinical decision-making.

Clinical outcomes of two-week sequential and concomitant therapies for Helicobacter pylori eradication: a randomized pilot study

BACKGROUND

The eradication rate with PPI-based standard triple therapy for Helicobacter pylori infection has fallen considerably. One recent innovation is sequential therapy with PPI and three antibiotics, but the complexity of this regimen may reduce its usability. Concomitant administration of nonbismuth quadruple drugs (concomitant therapy) is also an effective treatment strategy. To investigate which regimen is a reasonable choice for Korean population, we performed two pilot studies with sequential and concomitant therapies.

METHODS

A total of 164 patients with proven H. pylori infection randomly received 14 days of sequential (n = 86) or concomitant (n = 78) therapies. The sequential group received 20 mg rabeprazole and 1 g amoxicillin (first week), followed by 20 mg rabeprazole, 500 mg clarithromycin, and 500 mg metronidazole (second week). The concomitant group received 20 mg rabeprazole, 1 g amoxicillin, 500 mg clarithromycin, and 500 mg metronidazole for 2 weeks. All drugs were administered BID. Helicobacter pylori status was confirmed 4 weeks later, after completion of treatment by (13) C-urea breath test.

RESULTS

The intention-to-treat and per-protocol eradication rates were 75.6% (95% CI, 66.3-84.9) and 76.8% (95% CI, 67.1-85.5) in the sequential group, and 80.8% (95% CI, 71.8-88.5) and 81.3% (95% CI, 71.6-90.7) in the concomitant group. There were no significant between-group differences, in regard to the eradication rates, compliance, or side effects. The most common side effects were bitter taste, epigastric soreness, and diarrhea.

CONCLUSIONS

Two-week concomitant and sequential therapies showed suboptimal efficacies. However, considering high antibiotics resistance, either of these two regimens may be a reasonable choice for Korean population.

The efficacy of adefovir plus entecavir combination therapy in patients with chronic hepatitis B refractory to both lamivudine and adefovir

BACKGROUND

The efficacy of adefovir (ADV) plus entecavir (ETV) combination in patients with chronic hepatitis B (CHB) who developed multidrug refractoriness had not been fully evaluated. We aimed to evaluate the efficacy of ADV plus ETV as compared to that of lamivudine (LAM) plus ADV in the patients with antiviral refractoriness to sequential LAM monotherapy and then ADV monotherapy.

METHODS

Twenty-seven patients were treated with a combination of ADV plus ETV and 63 patients were treated with a combination of LAM plus ADV. The virological and biochemical parameters were compared between the two groups, retrospectively.

RESULTS

Treatment with a combination of ADV plus ETV produced significantly superior virological response than that of a combination of LAM plus ADV. At 12 months, the HBV DNA declined more in the ADV plus ETV group than in the LAM plus ADV (-4.52 ± 1.956 vs. -2.65 ± 1.723 log 10 IU/mL; p = 0.001). The rate of a complete response at 12 months was greater in the ADV plus ETV group than that in the LAM plus ADV group (63.16 vs. 14.81 %, p < 0.001).

CONCLUSION

In the patients with CHB refractory to both LAM and ADV, the response to ADV plus ETV was significantly superior compared to that of the LAM plus ADV in suppressing HBV DNA. The result indicates that ADV plus ETV can be used as a bridging therapy in the patients with refractoriness to both LAM and ADV, especially in the areas where tenofovir is not yet available.

Incidence and risk factors of irritable bowel syndrome in community subjects with culture-proven bacterial gastroenteritis

BACKGROUND/AIMS

The aim of this study was to investigate the incidence and risk factors of irritable bowel syndrome (IBS) in community subjects with culture-proven bacterial gastroenteritis.

METHODS

This was a prospective, community-based, cohort study, which followed patients with a recent history of culture-proven bacterial gastroenteritis. IBS was diagnosed with the use of the Rome II criteria at 3 and 6 months after bacterial dysentery.

RESULTS

Sixty five cases were included and completed the 6 month follow-up. Thirty four cases (52.3%) were female. Salmonella was the pathogen most frequently identified and seen in 41 patients (63.1%). The cumulative incidence of IBS among patients with microbiologically proven bacterial gastroenteritis within a community was 9.2% and 12.3% at 3 and 6 months of follow-up, respectively. The duration of initial diarrhea (≥ 7 days) was associated with an increased risk for the development of IBS (aOR, 14.50 [95% CI, 1.38-152.72]; p=0.022).

CONCLUSIONS

Our study suggests that the incidence of IBS among patients with culture-proven bacterial gastroenteritis within a community is similar to that reported among Western populations. A large, prospective study is encouraged to confirm our results and to evaluate the influence of the microbial species on the epidemiology of IBS in Asian populations.

Eradication of Helicobacter pylori reduces metachronous gastric cancer after endoscopic resection of early gastric cancer

BACKGROUND/AIMS

Although some studies have shown improvement of precancerous lesions and a decrease of metachronous gastric cancer after eradication of H. pylori, this is still controversial.

METHODOLOGY

We identified 74 patients with early gastric cancer and who had their H. pylori eradicated after undergoing endoscopic resection between September, 2003 and September, 2010. The endoscopic biopsy specimens, campylobacter-like organism test and urea breath test were reviewed. Relapse of gastric cancer was assessed from medical records.

RESULTS

Among the 74 patients, 61 (82.4%) were successfully eradicated. The mean duration of follow-up was 27.2±18.7 months. H. pylori colonization, neutrophil infiltration, mononuclear cell infiltration and intestinal metaplasia decreased after eradication (all p<0.05). For all the patients, metachronous gastric cancer showed a decrease in the eradicated group, but this did not reach statistical significance (odds ratio: 0.36, 95% CI: 0.08-1.70, p=0.189). However, when restricted to those who were followed-up for more than 18 months, metachronous gastric cancer was significantly decreased in the eradicated group (odds ratio: 0.108, 95% CI: 0.016-0.726, p=0.035).

CONCLUSIONS

Eradication of H. pylori decreased precancerous lesions, and when following-up for more than 18 months, eradication also reduced metachronous gastric cancer.

Higher prevalence of obesity in gastric cardia adenocarcinoma compared to gastric non-cardia adenocarcinoma

BACKGROUND AND AIMS

Obesity is one of the main risk factors for gastric cardia adenocarcinoma (GCA) in the West. Also, recent studies have suggested that GCA is distinct from distal stomach tumor, with differing risk factors, tumor characteristics, and biological behavior. The objective of our research was to evaluate the relationship between obesity and GCA compared to non-cardia adenocarcinoma.

MATERIALS AND METHODS

A total of 298 patients who were diagnosed with gastric adenocarcinoma and underwent surgery at Seoul National University Bundang Hospital were evaluated. Ninety-one cases were GCA, and 207 cases were non-cardiac adenocarcinoma. Obesity was estimated by body mass index (BMI, kg/m(2)). The degree of obesity was determined by using BMI <18.5, 18.5-23.9, 24-27.9, and ≥ 28 (kg/m(2)) as the cut-off points for underweight, normal weight, overweight, and obese, respectively. Association with obesity was estimated by odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Obesity was more prevalent in patients with GCA at the time of diagnosis for gastric cancer. Among obese persons with a BMI of 28 kg/m(2) or higher, the OR was 3.937 (95% CI, 1.492-10.389; p = 0.006) for GCA compared to non-cardia adenocarcinoma. For overweight individuals, the OR was 2.194 (95% CI, 1.118-4.305; p = 0.022). Multivariate analysis of age, Helicobacter pylori infection, smoking, stage, and BMI with logistic regression was performed. BMI was an independent risk factor for GCA (OR, 1.123; 95% CI, 1.037-1.217; p = 0.004).

CONCLUSION

Obesity was more prevalent in patients with GCA compared to that in patients with gastric non-cardia adenocarcinoma. Also, BMI was an independent risk factor for GCA.

[Clinical characteristics of patients diagnosed as peptic ulcer disease in the third referral center in 2007]

BACKGROUND/AIMS

In spite of the improvement of medical treatment for the peptic ulcer disease (PUD), PUD is still one of the common upper gastrointestinal diseases. The purpose of this study was to evaluate the risk factors and general characteristics of Korean patients diagnosed as PUD at a single third referral center.

METHODS

A total of 310 patients, diagnosed as PUD through endoscopy during one year of 2007 at Seoul National University Bundang Hospital were, retrospectively, evaluated regarding age, gender, Helicobacter pylori (H. pylori) positivity, clinical manifestations, comorbidities and medications. In addition, PUD was analyzed in the aspect of ulcer location, type of visit, gastrointestinal bleeding, and age.

RESULTS

The mean age was 61.5 years old (48.1% over 65) and 208 (66.7%) patients were men. The rate of H. pylori infection was 47.8%, and any ulcerogenic medication history such as antiplatelet agents and NSAIDs was found to be 21.0% (65 patients). The rate of idiopathic peptic ulcer without evidence of H. pylori and NSAIDs was found to be 40.6% (126 patients). Among 310 PUD patients, bleeding symptoms such as melena, hematemesis and hematochezia occurred in 110 patients (35.5%).

CONCLUSIONS

PUD was more prevalent in the elderly patients and frequently associated with bleeding. Substantial proportion of PUD patients had neither H. pylori infection nor history of ulcerogenic medications, suggesting of increasing prevalence of idiopathic PUD.

Nonalcoholic fatty liver disease is associated with coronary artery calcification

Nonalcoholic fatty liver disease (NAFLD) is related to risk factors of coronary artery disease, such as dyslipidemia, diabetes, and metabolic syndrome, which are closely linked with visceral adiposity. The aim of this study was to investigate whether NAFLD was associated with coronary artery calcification (CAC), which is used as a surrogate marker for coronary atherosclerosis independent of computed tomography (CT)-measured visceral adiposity. Out of 5,648 subjects who visited one of our health screening centers between 2003 and 2008, we enrolled 4,023 subjects (mean age, 56.9 ± 9.4 years; 60.7% males) without known liver disease or a history of ischemic heart disease. CAC score was evaluated using the Agatston method. On univariate analysis, the presence of CAC (score >0) was significantly associated with age, sex, body mass index, aspartate aminotransferase, alanine aminotransferase, high-density lipoprotein cholesterol, triglycerides, and increased risk of diabetes, hypertension, smoking, and NAFLD. Increasing CAC scores (0, <10, 10-100, ≥ 100) were associated with higher prevalence of NAFLD (odds ratio [OR], 1.84; 95% confidence interval [CI], 1.61-2.10; P<0.001). Multivariable ordinal regression analysis was adjusted for traditional risk factors, and CT-measured visceral adipose tissue area in a subgroup of subjects showed that the increased CAC scores were significantly associated with the presence of NAFLD (OR, 1.28, 95% CI, 1.04-1.59; P = 0.023) independent of visceral adiposity.

CONCLUSION

Patients with NAFLD are at increased risk for coronary atherosclerosis independent of classical coronary risk factors, including visceral adiposity. These data suggest that NAFLD might be an independent risk factor for coronary artery disease.

Comparison of cystatin C- and creatinine-based estimation of glomerular filtration rate according to glycaemic status in Type 2 diabetes

AIMS

The influence of hyperglycaemia on the performance of glomerular filtration rate (GFR) estimating equations remains to be determined. We compared the performance of creatinine-based GFR with cystatin C-based GFR in patients with Type 2 diabetes according to glycaemic status.

METHODS

In a cross-sectional study of 210 patients with Type 2 diabetes, we staged glycaemic status by HbA(1c) tertiles [HbA(1c) ≤ 75 mmol/mol (9.0%) (n = 70), HbA(1c) 76-95 mmol/mol (9.1-10.8%) (n = 70), HbA(1c) >95 mmol/mol (10.8%) (n = 70)] and measured GFR. Isotopic GFR was measured using renal dynamic imaging with (99m) Tc-diethylene-triamine-penta-acetic acid. Estimated GFR (eGFR) was measured using creatinine-based formulae (Cockcroft-Gault-eGFR, the Modification of Diet in Renal Disease equation-eGFR and the Chronic Kidney Disease Epidemiology Collaboration formula-eGFR) and a cystatin C-based formula (cystatin C-eGFR).

RESULTS

The isotopic GFR of all patients was 93.1 ± 34.1 ml min(-1) 1.73 m(-2). All methods for estimating GFR underestimated isotopic GFR [Cockcroft-Gault-eGFR (68.8 ± 38.6 ml min(-1) 1.73 m(-2) ) (P < 0.05), Modification of Diet in Renal Disease-eGFR (74.8 ± 31.3 ml min(-1) 1.73 m(-2) ) (P < 0.05), Chronic Kidney Disease Epidemiology Collaboration-eGFR (72.9 ± 26.6 ml min(-1) 1.73 m(-2)) (P < 0.05) and cystatin C-eGFR (83.5 ± 33.2 ml min(-1) 1.73 m(-2)) (P < 0.05)]. In all patient groups, cystatin C-eGFR was less biased and more accurate than the creatinine-based formulae, especially in the group with HbA(1c) > 95 mmol/mol (10.8%) where there was no difference between cystatin C-eGFR and isotopic GFR.

CONCLUSIONS

Performance of cystatin C-eGFR was superior to creatinine-based GFR in patients with Type 2 diabetes with HbA(1c) >95 mmol/mol (10.8%).

Pretreatment serum HBsAg-to-HBV DNA ratio predicts a virologic response to entecavir in chronic hepatitis B

Background/Aims

Decay of hepatitis B surface antigen (HBsAg) titers has previously been shown to be predictive of a virologic response (VR), especially during peginterferon-alpha therapy. However, the role of HBsAg levels in predicting a VR to nucleos(t)ide analog therapy has not yet been established. In this study we sought to determine whether the VR can be predicted from HBsAg titers in nucleos(t)ide-naïve chronic hepatitis B (CHB) patients treated with entecavir.

Methods

CHB patients who started entecavir as an initial antiviral therapy were enrolled in this study. Serum hepatitis B virus (HBV) DNA, HBsAg, and alanine aminotransferase levels were measured every 3 months during treatment. A VR was defined as undetectable serum HBV DNA titer by real-time PCR assay (<60 IU/mL).

Results

Fifty-two patients were enrolled, and the median duration of treatment was 26 months (range 7-35 months). Forty-five patients achieved a VR; the cumulative VR rates at 3, 6, 12, and 24 months were 40%, 71.2%, 81.5%, and 88%, respectively. Baseline HBV DNA levels were significantly lower in patients with VR, whereas the HBsAg levels did not differ significantly between patients with or without VR. In a univariate analysis the cumulative VR rate was significantly higher in HBeAg negative patients and patients with an HBsAg/HBV DNA ratio above 0.56. However, in a multivariate analysis only an HBsAg/HBV DNA ratio above 0.56 was an independent predictor of VR (P=0.003). The area under the receiver operating characteristic curve was larger for the HBsAg/HBV DNA ratio than for either HBV DNA or HBsAg.

Conclusions

Pretreatment HBsAg/HBV DNA ratio can predict a long-term VR to entecavir therapy in nucleos(t)ide-naïve CHB patients.

Coinfection of hepatitis A virus genotype IA and IIIA complicated with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive immunoglobulin M anti-hepatitis E virus: a case report

A 37-year-old male presented with fever and jaundice was diagnosed as hepatitis A complicated with progressive cholestasis and severe autoimmune hemolytic anemia. He was treated with high-dose prednisolone (1.5 mg/kg), and eventually recovered. His initial serum contained genotype IA hepatitis A virus (HAV), which was subsequently replaced by genotype IIIA HAV. Moreover, at the time of development of hemolytic anemia, he became positive for immunoglobulin M (IgM) anti-hepatitis E virus (HEV). We detected HAV antigens in the liver biopsy specimen, while we detected neither HEV antigen in the liver nor HEV RNA in his serum. This is the first report of hepatitis A coinfected with two different genotypes manifesting with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive IgM anti-HEV.

Modification of fullerene nanocolumn structure by accelerated C60 ions

Crystalline C60 and amorphous graphite-like films of nanocolumn arrays fabricated by glancing angle deposition of C60 fullerene at substrate temperatures of -425 K were studied by transmission electron microscopy (TEM) and atomic-force microscopy (AFM). Characteristic dimension of columns is 200-400 nm. We used co-deposition of C60 molecules and accelerated C60 ions to modify the structure and properties of nanocolumn arrays. Influence of incidence angle for C60 ions on formation of film morphology was revealed. Raman spectrum analysis showed that amorphous carbon nanocolumns consist of nanographite areas with average size of -1.5 nm. The films have high conductivity (close to graphite) and have no mechanical stresses. The carbon films were applied in all-solid-state rechargeable thin-film battery as an anode layer. The nanocolumn amorphous carbon film as anode electrode showed the discharge capacity of about 50 microAh cm(-2)microm(-1) and good cycling ability over 100 times in full cell system.

Dissemination of ceftazidime-resistant Acinetobacter baumannii clonal complex 92 in Korea

AIMS

This study was performed to describe the epidemiological traits of ceftazidime-resistant Acinetobacter baumannii clinical isolates from Korea.

METHODS AND RESULTS

Antimicrobial susceptibilities were determined by disk diffusion assay. PCR experiments were performed to detect genes encoding extended-spectrum β-lactamases and metallo-β-lactamases. Detection of ISAba1 upstream of the bla(ADC) gene was also performed by PCR amplification. The genetic organization of the bla(PER-1) gene was investigated by PCR mapping and sequencing of the regions surrounding the gene. Multilocus sequence typing was performed using seven housekeeping genes. A. baumannii isolates of clonal complex (CC) 92 exhibited a higher resistance rate (286/289, 99%) against ceftazidime compared to A. baumannii isolates of non-CC92 (7/87, 8%). Amongst 286 ceftazidime-resistant isolates of CC92, 100 (35%) isolates carried the bla(PER-1) gene, while none of the 87 isolates of non-CC92 carried the gene. The bla(ADC) gene associated with an ISAba1 element was detected in 98% (281/286) of ceftazidime-resistant isolates of CC92 and in all seven ceftazidime-resistant isolates of non-CC92. The bla(PER-1) gene was located on a transposon, Tn1213 (ISPa12-bla(PER-1) -Δgst-ISPa13), in 95 isolates and on a complex class 1 integron (orf513-bla(PER-1) -putative ABC transporter gene) in five isolates. Southern blot experiments confirmed the chromosomal location of the bla(PER-1) gene.

CONCLUSIONS

Acinetobacter baumannii CC92 which has acquired ceftazidime resistance by the production of PER-1 extended-spectrum β-lactamases and/or the overproduction of Acinetobacter-derived cephalosporinase is widely disseminated in Korea.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study shows the mechanisms of acquiring ceftazidime resistance in A. baumannii and the epidemiological traits of ceftazidime-resistant A. baumannii isolates from Korea.

[Effects of proton pump inhibitors in asthmatics with gastroesophageal reflux disease]

BACKGROUND/AIMS

Gastroesophageal reflux disease (GERD) is common in asthma patients. Proton pump inhibitor (PPI) therapy improves symptoms of asthma in some patients. The objective of this study was to investigate endoscopic findings of GERD in asthma patients and to assess the effect of gastric acid suppression with the PPIs on symptom improvement and pulmonary function.

METHODS

From 105 consecutive patients with GERD symptoms during follow up for asthma, 45 patients were enrolled. Patients enrolled to this study were asked about GERD symptoms before and after treating with PPI. Endoscopic findings were described according to Los Angeles classification. The improvement of asthma symptoms and follow-up pulmonary function test were investigated after administration of PPIs.

RESULTS

Esophageal symptoms such as heartburn and acid reflux were present in 25 patients (55.6%), and patients without esophageal symptoms were 20 (44.4%). The degree of endoscopic abnormality was not significantly different between groups with or without esophageal symptoms. The improvement of symptoms was seen in 44 patients (97.8%) except 1 patient after administration of PPIs. The number of patients classified to the low-dose group was 7 patients (15.6%) and that of patients classified to the standard-dose group was 38 patients (84.4%). The follow-up pulmonary function test, peak expiratory flow rate (L/sec) was improved in 3 patients (3 of 7, 42.9%) of the low-dose group, and in 24 patients (24 of 38, 63.2%) of the standard-dose group. The improvement of ventilatory function was not significantly different according to dose of PPIs.

CONCLUSIONS

Treatment with PPIs is expected to improve subjective symptoms and ventilatory function in asthma patients.

First neutral beam injection experiments on KSTAR tokamak

The first neutral beam (NB) injection system of the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak was partially completed in 2010 with only 1∕3 of its full design capability, and NB heating experiments were carried out during the 2010 KSTAR operation campaign. The ion source is composed of a JAEA bucket plasma generator and a KAERI large multi-aperture accelerator assembly, which is designed to deliver a 1.5 MW, NB power of deuterium at 95 keV. Before the beam injection experiments, discharge, and beam extraction characteristics of the ion source were investigated. The ion source has good beam optics in a broad range of beam perveance. The optimum perveance is 1.1-1.3 μP, and the minimum beam divergence angle measured by the Doppler shift spectroscopy is 0.8°. The ion species ratio is D(+):D(2)(+):D(3)(+) = 75:20:5 at beam current density of 85 mA/cm(2). The arc efficiency is more than 1.0 A∕kW. In the 2010 KSTAR campaign, a deuterium NB power of 0.7-1.5 MW was successfully injected into the KSTAR plasma with a beam energy of 70-90 keV. L-H transitions were observed within a wide range of beam powers relative to a threshold value. The edge pedestal formation in the T(i) and T(e) profiles was verified through CES and electron cyclotron emission diagnostics. In every deuterium NB injection, a burst of D-D neutrons was recorded, and increases in the ion temperature and plasma stored energy were found.

[Primary antibiotic resistance of Helicobacter pylori strains and eradication rate according to gastroduodenal disease in Korea]

BACKGROUND/AIMS

This study was performed to evaluate whether the prevalence rates of primary antibiotic resistance in Helicobacter pylori (H. pylori) isolates and the eradication rate of H. pylori could be different between cancer and non-cancer patients.

METHODS

H. pylori were isolated from gastric mucosal biopsy specimens obtained from 269 Koreans, who did not have any eradication therapy history and were diagnosed as one of the following diseases; chronic gastritis, benign gastric ulcer, duodenal ulcer or gastric cancer. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, ciprofloxacin, levofloxacin and moxifloxacin were examined with the agar dilution method. In addition, eradication rate of H. pylori was evaluated.

RESULTS

There was no significant difference in the primary antibiotic resistance to above eight antibiotics among chronic gastritis, peptic ulcer disease and gastric cancer. Furthermore there was no difference of antibiotic resistance between cancer and non-cancer patients, and there was no difference of eradication rate of H. pylori according to disease.

CONCLUSIONS

Primary antibiotic resistance and H. pylori eradication rate were not different between cancer and non-cancer patients.

A nationwide seroprevalence of total antibody to hepatitis A virus from 2005 to 2009: age and area-adjusted prevalence rates

Background/Aims

Recent outbreak of hepatitis A in Korea is clearly related to the epidemiological shift of hepatitis A virus (HAV). However, nationwide seroprevalence data have been limited. This study estimated the nationwide, age- and area-adjusted anti-HAV prevalence from 2005 to 2009.

Methods

Retrospective analysis of the results of total anti-HAV test in 25,140 cases which were requested by 1,699 medical institutions throughout the nation to Seoul Clinical Laboratory from Jan. 1 2005 to Dec. 31 2009 was performed. The estimated seroprevalence was adjusted by area and age of the standard population based on the 2005 Census data from Korea National Statistical Office.

Results

The area-adjusted anti-HAV prevalence in the children younger than 10 years were 33.4% in 2005 and 69.9% in 2009. The most susceptible age groups to HAV infection during the last 5 years were teenagers and the young adults in their age of twenties. The area-adjusted seroprevalence in 2009 were 11.9% in the age group of 20-29 years, 23.4% in the age group of 10-19 years, 48.4% in the age group of 30-39 years. The population in 40-49 years showed geographically different seroprevalence with the lowest rate in Seoul (80%).

Conclusions

The most susceptible age group to HAV infection is 10-29 years, while the young children less than 10 years showed about 70% seropositivity. The changing seroepidemiology should be monitored continuously for the proper vaccination and patient care.

Development of a plasma generator for a long pulse ion source for neutral beam injectors

A plasma generator for a long pulse H(+)/D(+) ion source has been developed. The plasma generator was designed to produce 65 A H(+)/D(+) beams at an energy of 120 keV from an ion extraction area of 12 cm in width and 45 cm in length. Configuration of the plasma generator is a multi-cusp bucket type with SmCo permanent magnets. Dimension of a plasma chamber is 25 cm in width, 59 cm in length, and 32.5 cm in depth. The plasma generator was designed and fabricated at Japan Atomic Energy Agency. Source plasma generation and beam extraction tests for hydrogen coupling with an accelerator of the KSTAR ion source have been performed at the KSTAR neutral beam test stand under the agreement of Japan-Korea collaborative experiment. Spatial uniformity of the source plasma at the extraction region was measured using Langmuir probes and ±7% of the deviation from an averaged ion saturation current density was obtained. A long pulse test of the plasma generation up to 200 s with an arc discharge power of 70 kW has been successfully demonstrated. The arc discharge power satisfies the requirement of the beam production for the KSTAR NBI. A 70 keV, 41 A, 5 s hydrogen ion beam has been extracted with a high arc efficiency of 0.9 -1.1 A/kW at a beam extraction experiment. A deuteron yield of 77% was measured even at a low beam current density of 73 mA/cm(2).

[Risk factors for development and recurrence of peptic ulcer disease]

BACKGROUND/AIMS

Peptic ulcer disease (PUD) is one of the common gastrointestinal diseases, and its medical management has been developed so much that the incidence of its serious complications, such as bleeding and perforation, are declining significantly. Its prevalence in Korea is not definitely decreased, probably due to increasing proportion of elderly patients and their rising usage of non-steroidal anti-inflammatory drugs (NSAIDs) and aspirin. This study was conducted to identify the risk factors for development and recurrence of peptic ulcer disease in Korea.

METHODS

From 2003 to 2008, upper gastrointestinal endoscopy and detailed personal questionnaires were performed for patients who visited Department of Gastroenterology at Seoul National University Bundang Hospital. In total, 475 PUD patients and 335 non-ulcer dyspepsia patients were included. The results of questionnaires and repeated upper gastrointestinal endoscopy at initial diagnosis time and follow-up periods were analyzed.

RESULTS

Multivariable analysis showed that male, H. pylori infection, NSAIDs use and smoking were risk factors for the development of PUD. The use of proton pump inhibitors (PPIs) and H2 receptor antagonists has significantly reduced the risk of PUD in patients who had taken NSAIDs and/or aspirin. H. pylori infection was found as the only risk factor for the recurrence of PUD.

CONCLUSIONS

For the old patients who are taking drugs, such as NSAIDs and aspirin, concomitant use of PPIs or H2 receptor antagonists should be considered to protect from the development of PUD. H. pylori eradication has been confirmed again to be essential for the treatment of PUD patients infected with H. pylori.

Relatively scaled ECE temperature profiles of KSTAR plasmas

A scheme to obtain relatively scaled profiles of electron cyclotron emission (ECE) temperature directly from uncalibrated raw radiometer data is proposed and has been tested for the 2009 campaign KSTAR plasmas. The proposed method utilizes a position controlled system to move the plasma adiabatically and compares ECE radiometer channels at the same relative radial positions assuming the profile consistency during the adiabatic change. This scaling method is an alternative solution when an absolute calibration is unreliable or too time consuming. The application to the two dimensional ECE imaging data, wherein calibration is extremely difficult, may also prove to be useful.

Calibration of electron cyclotron emission radiometer for KSTAR

We developed and installed an electron cyclotron emission radiometer for taking measurements of Korea Superconducting Tokamak Advanced Research (KSTAR) plasma. In order to precisely measure the absolute value of electron temperatures, a calibration measurement of the whole radiometer system was performed, which confirmed that the radiometer has an acceptably linear output signal for changes in input temperature. It was also found that the output power level predicted by a theoretical calculation agrees with that obtained by the calibration measurement. We also showed that the system displays acceptable noise-temperature performance around 0.23 eV.

Electron cyclotron emission diagnostics on KSTAR tokamak

A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.

Diagnostics for first plasma and development plan on KSTAR

The first plasma with target values of the plasma current and the pulse duration was finally achieved on June 13, 2008 in the Korea Superconducting Tokamak Advanced Research (KSTAR). The diagnostic systems played an important role in achieving successful first plasma operation for the KSTAR tokamak. The employed plasma diagnostic systems for the KSTAR first plasma including the magnetic diagnostics, millimeter-wave interferometer, inspection illuminator, H(alpha), visible spectrometer, filterscope, and electron cyclotron emission (ECE) radiometer have provided the main plasma parameters, which are essential for the plasma generation, control, and physics understanding. Improvements to the first diagnostic systems and additional diagnostics including an x-ray imaging crystal spectrometer, reflectometer, ECE radiometer, resistive bolometer, and soft x-ray array are scheduled to be added for the next KSTAR experimental campaign in 2009.

[Efficacy and predictors of the virologic response to entecavir therapy in nucleoside-naive patients with chronic hepatitis B]

BACKGROUND/AIMS

The aim of this study was to elucidate the antiviral efficacy and the predictors of entecavir treatment in nucleoside-naive chronic hepatitis B patients.

METHODS

A total of 160 patients treated with entecavir (0.5 mg daily) for at least 24 weeks were consecutively enrolled. The virologic response (HBV DNA<2,000 copies/mL), biochemical response (ALT< or = upper limit of normal), and virologic breakthrough (>1 log(10) copies/mL increase in HBV DNA level above nadir on two consecutive occasions) were retrospectively analyzed.

RESULTS

The mean follow-up duration was 58.8 weeks, and 85 patients (53.1%) showed HBeAg positivity. The median pretreatment levels of serum ALT and HBV DNA were 99 IU/L and 7.6 log(10) copies/mL, respectively. The cumulative rates at 12, 24, 48, and 72 weeks were 37.5%, 68.1%, 87.4%, and 95.8%, respectively, for the virologic response; 40.0%, 66.2%, 84.5%, and 92.7% for the biochemical response; 10.6%, 18.8%, 27.0%, and 34.5% for HBeAg loss; and 3.5%, 7.1%, 9.0%, and 13.2% for HBeAg seroconversion. There was no case of virologic breakthrough. An absence of HBeAg and a low serum HBV DNA level (<8 log(10) copies/mL) at baseline were significant predictors of the virologic response in a multivariate analysis (P<0.01).

CONCLUSIONS

Entecavir therapy showed excellent efficacy in nucleoside-naive chronic hepatitis B patients. The predictors of a virologic response were an absence of HBeAg and a low baseline HBV DNA level.

Comparison of risk factors and clinical responses to proton pump inhibitors in patients with erosive oesophagitis and non-erosive reflux disease

BACKGROUND

There has been no report on the response to proton pump inhibitor (PPI) therapy and on-demand or the relapse rate of non-erosive reflux disease (NERD) and erosive oesophagitis in Korea.

AIM

To compare the risk factors, clinical symptoms and PPI responses between patients with erosive oesophagitis and NERD patients.

METHODS

A survey was performed prospectively in the erosive oesophagitis (205 patients) and NERD group (200 patients). Clinical symptoms, risk factors and PPI responses were analysed. On-demand therapy and the relapse rate of GERD symptoms were investigated during a one-year follow-up.

RESULTS

BMI > or = 25 (OR 3.0, 95% CI 1.1-8.3), alcohol use (OR 2.9, 95% CI 1.0-8.3), hiatal hernia (OR 5.0, 95% CI 1.2-20) and triglyceride > or =150 mg/dL (OR 4.0, 95% CI 1.7-10) were more common in the erosive oesophagitis group than in the NERD group by multivariate analysis. The ratio of oesophageal to extra-oesophageal symptoms was higher in the erosive oesophagitis group compared with the NERD group (P < 0.001). The PPI response rates at 8 weeks were different (P = 0.02); refractory rates were higher in the NERD group (16.7%) compared with the erosive oesophagitis group (6.0%). However, there was no significant difference between the two groups in on-demand therapy or the relapse rate.

CONCLUSION

These results suggest that the underlying pathogenic mechanisms of erosive oesophagitis and NERD are distinct.

The rapid growth of vertically aligned carbon nanotubes using laser heating

Growth of densely packed vertically aligned carbon nanotubes (VA-CNTs) using laser-induced chemical vapor deposition with visible laser (lambda = 532 nm) irradiation at room temperature is reported. Using a multiple-catalyst layer (Fe/Al/Cr) on quartz as the substrate and an acetylene-hydrogen mixture as the precursor gas, VA-CNT pillars with 60 microm height and 4 microm diameter were grown at a high rate of around 1 microm s(-1) with good reproducibility. It is demonstrated that the fabrication of uniform pillar arrays of VA-CNTs can be achieved with a single irradiation for each pillar using LCVD with no annealing or preprocessing of the substrate. Here, laser fast heating is considered the primary mechanism facilitating the growth of VA-CNT pillars. Field emission characteristics of an array of VA-CNT pillars were then examined to investigate their potential application in vacuum electronic devices.