Most gastric cancers are caused by infection with the common human bacterial pathogen, Helicobacter pylori. It is now accepted that gastric cancer can be prevented and virtually eliminated by H. pylori eradication and this knowledge was responsible for country-wide H. pylori eradication combined with secondary cancer prevention for those with residual risk that was introduced in Japan in 2013. Korea is a high H. pylori prevalence and high gastric cancer incidence country and a good candidate for a gastric cancer elimination program. The presence of an H. pylori infection is now considered as an indication for treatment of the infection. However, antimicrobial drug resistance is common among H. pylori in Korea making effective therapy problematic. Country-wide studies of the local and regional antimicrobial resistance patterns are needed to choose the most appropriate therapies. H. pylori and gastric cancer eradication can be both efficient and cost effective making it possible and practical to make Korea H. pylori and gastric cancer free. There is no reason to delay.

In women receiving evaluation for suspected ischemic symptoms, a "normal" diagnosis is five times more common than it is in men. These women are often labeled as having cardiac syndrome X, also known as microvascular angina (MVA). MVA is defined as angina pectoris caused by abnormalities of the small coronary arteries, and is characterized by effort chest pain and evidence of myocardial ischemia with a non-invasive stress test, although the coronary arteries can appear normal or near normal by angiography. MVA patients are often neglected due to the assumption of a good prognosis. However, MVA has important prognostic implications and a proper diagnosis is necessary in order to relieve the patients' symptoms and improve clinical outcomes. The coronary microvasculature cannot be directly imaged using coronary angiography, due to the small diameter of the vessels; therefore, the coronary microvascular must be assessed functionally. Treatment of MVA initially includes standard anti-ischemic drugs (${\beta}$-blockers, calcium antagonists, and nitrates), although control of symptoms is often insufficient. In this review, we discuss the pathophysiology, diagnosis, and treatment of MVA.

The complex interaction of molecules within a biological system constitutes a functional module. These modules are then acted upon by both internal and external factors, such as genetic and environmental stresses, which under certain conditions can manifest as complex disease phenotypes. Recent advances in high-throughput biological analyses, in combination with improved computational methods for data enrichment, functional annotation, and network visualization, have enabled a much deeper understanding of the mechanisms underlying important biological processes by identifying functional modules that are temporally and spatially perturbed in the context of disease development. Systems biology approaches such as these have produced compelling observations that would be impossible to replicate using classical methodologies, with greater insights expected as both the technology and methods improve in the coming years. Here, we examine the use of systems biology and network analysis in the study of a wide range of rheumatic diseases to better understand the underlying molecular and clinical features.

Background/Aims: The clinical outcome of patients with a partial virological response (PVR) to entecavir (ETV), in particular nucloes(t)ide analogue (NA)-experienced patients, has not been thoroughly investigated. The aim of the present study was to assess long-term outcomes in NA-naive and NA-experienced chronic hepatitis B patients with a PVR to ETV. Methods: Chronic hepatitis B patients treated with ETV (0.5 mg/day) for at least 1 year were enrolled retrospectively. PVR was defined as a decrease in hepatitis B virus (HBV) DNA titer of more than $2log_{10}\;IU/mL$, yet with residual serum HBV DNA, as determined by real time-polymerase chain reaction, at week 48 of ETV therapy. Results: A total of 202 patients (127 NA-naive and 75 NA-experienced, male 70.8%, antigen positive 53.2%, baseline serum HBV DNA $6.2{\pm}1.5log_{10}\;IU/mL$) were analyzed. Twenty-eight patients demonstrated a PVR. The PVR was associated with a high serum HBV DNA titer at baseline and at week 24. Virological response (< 60 IU/mL) was achieved in 46.2%, 61.5%, 77.6%, and 85% of patients with PVR at week 72, 96, 144, and 192, respectively. Resistance to antivirals developed in two NA-experienced patients. Failure of virological response (VR) in patients with PVR was associated with high levels of serum HBV DNA at week 48. Conclusions: Patients with PVR to ETV had favorable long-term virological outcomes. The low serum level of HBV DNA (< 200 IU/mL) at week 48 was associated with subsequent development of a VR in patients with PVR to ETV.

Background/Aims: The aim of this study was to compare the risk of complications and outcome between infarct-related artery (IRA)-only revascularization and multivessel (MV) revascularization in patients with acute myocardial infarction (MI) with renal insufficiency and MV disease. Methods: A total of 1,031 acute MI patients with renal insufficiency and MV disease who were registered in the Korea Working Group on Myocardial Infarction were enrolled. They were divided into two groups (IRA-only revascularization group, n = 404; MV revascularization group, n = 627), and investigated the cumulative incidence of major adverse cardiac events (MACE) and the incidence of complications after percutaneous coronary intervention (PCI). Results: Complications after PCI occurred in 19.9% of all patients (206/1,031). Complications after PCI occurred more frequently in the MV revascularization group compared with the IRA-only revascularization group (20.1% [126/627] vs. 15.3% [62/404], respectively; p = 0.029]. The overall in-hospital mortality rate was 6.3%, and there was no significant difference between the groups (5.2% in the IRA-only revascularization group vs. 7.0% in the MV revascularization group; p = 0.241). The total incidence of MACE was 11.1%, and there was no significant difference between the groups (11.6% in the IRA-only revascularization group vs. 10.7% in the MV revascularization group; p = 0.636). Conclusions: The incidence of complications after PCI was significantly lower in the IRA-only revascularization group compared with the MV revascularization group. However, there were no significant difference in the 12-month outcomes between groups in patients with acute MI and renal insufficiency with MV disease.

Background/Aims: Cigarette smoking is the most common risk factor for chronic obstructive pulmonary disease (COPD). However, few studies of the attitudes toward COPD of smokers, the group at risk of developing this condition, have been conducted. The purpose of this study was to explore the awareness of and attitudes toward COPD of current smokers. Methods: The sample consisted of 502 individuals aged 45 and older from throughout Korea who smoked at least 10 packs of cigarettes per year. Telephone interviews using a structured questionnaire were conducted with respondents. Results: First, we evaluated the health status of subjects, finding that 45.4% considered themselves to be in good health. We also asked about COPD-related symptoms, and 60.6% of subjects reported such symptoms. However, only 1.2% of subjects had been diagnosed with or treated for COPD, only 0.4% spontaneously mentioned COPD as a respiratory disease, and only 26.5% recognized COPD as a respiratory disease after seeing a list of such diseases. Television ranked as the top source of information about COPD. The willingness of 45.0% of subjects to stop smoking increased after being informed about COPD. Conclusions: Despite having COPD-related symptoms, most smokers did not know that COPD is a respiratory disease. The attitudes of smokers toward COPD and smoking cessation varied according to socioeconomic status. In summary, a continuous effort to increase the awareness of COPD among smokers is needed. Additionally, strategies tailored according to different socioeconomic groups will also be necessary.

Background/Aims: Serum procalcitonin (PCT) levels are low in healthy individuals but are elevated in patients with a serious bacterial infection or sepsis. In this study, we examined the ability of serum PCT concentration to diagnose infections in end-stage renal disease (ESRD) patients, and sought to determine an appropriate threshold level. Methods: Serum PCT levels were measured in ESRD patients on antibiotic therapy for a suspected bacterial infection (ESRD infection [iESRD] group, n = 21), and compared with those of ESRD patients on hemodialysis with no sign of infection (ESRD control [cESRD] group, n = 20). Results: The mean serum PCT concentration of the iESRD group was significantly higher than in the cESRD group ($2.95{\pm}3.67ng/mL$ vs. $0.50{\pm}0.49ng/mL$, p = 0.006), but serum PCT concentrations did not correlate with severity of infection. The optimized threshold level derived for serum PCT was 0.75 ng/mL, rather than the currently used 0.5 ng/mL; this threshold demonstrated a sensitivity and specificity of 76.2% and 80.0% for infection and 100% and 60.6% for systemic inflammatory response syndrome, respectively, compared with the cutoff of 0.5 ng/mL. Conclusions: This study suggests that serum PCT at a cutoff value of 0.75 ng/mL is an appropriate indicator of infection in ESRD patients.

Background/Aims: New definitions of acute kidney injury (AKI) have recently emerged. Some studies have suggested that duration of AKI is an additional predictive parameter for mortality. Here, we evaluated whether AKI duration was predictive of long-term mortality in patients with hospital-acquired acute kidney injury (HAAKI). Methods: We prospectively enrolled patients who developed HAAKI at an urban university hospital, from September 2007 to August 2008 and followed them until December 2011. Patients were divided into two groups by duration of the AKI (1 to 5 days vs. ${\geq}6days$), and long-term mortality was compared. Results: HAAKI developed in 1.2% of patients during the enrollment period. The median follow-up period was 240 days (interquartile range, 53 to 1,428). In 42.3% of patients (n = 52), the AKI lasted 1 to 5 days, while it lasted ${\geq}6days$ in 57.7% (n = 71). Survival analysis showed that a longer duration of AKI increased the risk of death. Long-term survival was significantly different in the two groups. Conclusions: The duration of AKI influenced mortality rates in hospitalized patients. Thus, AKI duration is a parameter affecting mortality in HAAKI.

Background/Aims: BK virus (BKV) has been associated with late-onset hemorrhagic cystitis (HC) in recipients of hematopoietic stem cell transplantation (HSCT). Cidofovir has been used at higher doses (3 to 5 mg/kg/wk) with probenecid prophylaxis; however, cidofovir may result in nephrotoxicity or cytopenia at high doses. Methods: Allogeneic HSCT recipients with BKV-associated HC are treated with 1 mg/kg intravenous cidofovir weekly at our institution. A microbiological response was defined as at least a one log reduction in urinary BKV viral load, and a clinical response was defined as improvement in symptoms and stability or reduction in cystitis grade. Results: Eight patients received a median of 4 weekly (range, 2 to 11) doses of cidofovir. HC occurred a median 69 days (range, 16 to 311) after allogeneic HSCT. A clinical response was detected in 7/8 patients (86%), and 4/5 (80%) had a measurable microbiological response. One patient died of uncontrolled graft-versus-host disease; therefore, we could not measure the clinical response to HC treatment. One microbiological non-responder had a stable BKV viral load with clinical improvement. Only three patients showed transient grade 2 serum creatinine toxicities, which resolved after completion of concomitant calcineurin inhibitor treatment. Conclusions: Weekly intravenous low-dose cidofovir without probenecid appears to be a safe and effective treatment option for patients with BKV-associated HC.

Background/Aims: Providencia species frequently colonize urinary catheters and cause urinary tract infections (UTIs); however, bacteremia is uncommon and not well understood. We investigated the clinical features of Providencia bacteremia and the antibiotic susceptibility of Providencia species. Methods: We identified cases of Providencia bacteremia from May 2001 to April 2013 at a tertiary care hospital. The medical records of pertinent patients were reviewed. Results: Fourteen cases of Providencia bacteremia occurred; the incidence rate was 0.41 per 10,000 admissions. The median age of the patients was 64.5 years. Eleven cases (78.6%) were nosocomial infections and nine cases (64.3%) were polymicrobial bacteremia. The most common underlying conditions were cerebrovascular/neurologic disease (n = 10) and an indwelling urinary catheter (n = 10, 71.4%). A UTI was the most common source of bacteremia (n = 5, 35.7%). The overall mortality rate was 29% (n = 4); in each case, death occurred within 4 days of the onset of bacteremia. Primary bacteremia was more fatal than other types of bacteremia (mortality rate, 75% [3/4] vs. 10% [1/10], p = 0.041). The underlying disease severity, Acute Physiologic and Chronic Health Evaluation II scores, and Pitt bacteremia scores were significantly higher in nonsurvivors ( p = 0.016, p =0.004, and p = 0.002, respectively). Susceptibility to cefepime, imipenem, and piperacillin/tazobactam was noted in 100%, 86%, and 86% of the isolates, respectively. Conclusions: Providencia bacteremia occurred frequently in elderly patients with cerebrovascular or neurologic disease. Although Providencia bacteremia is uncommon, it can be rapidly fatal and polymicrobial. These characteristics suggest that the selection of appropriate antibiotic therapy could be complicated in Providencia bacteremia.

Background/Aims: We sought to increase our understanding of the rhinitis-asthma relationship and improve strategies for the treatment of patients with these diseases. The aim of this study was to identify a connection between upper airway inflammation and lower airway responsiveness. Methods: We counted eosinophils on nasal smears, and performed spirometry, allergic skin tests, and methacholine challenge tests in 308 schoolchildren plus a questionnaire on respiratory symptoms. The methacholine concentration causing a 20% fall in forced expiratory volume in 1 second ($PC_{20}$ < 25 mg/mL) was used as the threshold of bronchial hyperresponsiveness (BHR). Results: In total, 26% of subjects had positive nasal eosinophils on a smear, and 46.2% of subjects had BHR at < 25 mg/mL methacholine $PC_{20}$. Nasal symptoms were higher in subjects with than without nasal eosinophils (p = 0.012). Asthma symptoms did not differ between subjects with and without nasal eosinophils. Nasal eosinophils were higher in subjects with atopy than those without (p = 0.006), and there was no difference in $PC_{20}$ methacholine according to atopy ($15.5{\pm}1.07$ vs. $17.5{\pm}0.62$; p > 0.05). No difference in BHR was detected when comparing subjects with and without nasal eosinophils. There were significant differences in the $PC_{20}$ between subjects with greater than 50% nasal eosinophils and without nasal eosinophils ($11.01{\pm}2.92mg/mL$ vs. $17.38{\pm}0.61mg/mL$; p < 0.001). Conclusions: These findings demonstrated that nasal eosinophilic inflammation might contribute to lower airway responsiveness in schoolchildren, based on an epidemiological survey.

Background/Aims: We investigated whether transthoracic echocardiographysuspected pulmonary hypertension (PH) affects survival in systemic lupus erythematosus (SLE) patients and examined factors associated with PH occurrence and survival. Methods: This retrospective single-center study included 154 Korean SLE patients fulfilling the American College of Rheumatology criteria (January 1995 to June 2013). Student t test, Mann-Whitney U test, Kaplan-Meier curves, and log-rank tests were used for comparisons. Results: A total of 35 SLE patients with PH (SLE/PH+) and 119 without PH (SLE/PH-) were analyzed. Higher percentages of interstitial lung disease, Raynaud's phenomenon (RP), World Health Organization functional classification III/IV, and cardiomegaly were found in SLE/PH+ compared to SLE/PH-. Furthermore, the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index was significantly higher in SLE/PH+ ($2.46{\pm}1.245$ vs. $1.00{\pm}1.235$), whereas survival rates were significantly higher in SLE/PH- in log-rank tests (p = 0.001). In multivariate analysis, the adjusted mortality hazard ratio (HR) for SLE/PH+ patients was 3.10. Subgroup analysis demonstrated a higher percentage of lupus nephritis in the SLE/PH+ patients who died (p = 0.039) and low complement-3 levels (p = 0.007). In univariate analysis, the mortality HR for SLE/PH+ patients with lupus nephritis was 4.62, whereas the presence of RP decreased the mortality risk in multivariate analysis; adjusted HR, 0.10. Conclusions: PH is an independent factor predicting survival in SLE patients. The presence of lupus nephritis resulted in an increased trend for mortality, whereas coexistence of RP was associated with a better survival prognosis in SLE/PH+ patients.

Background/Aims: To compare the clinical characteristics and outcomes of systemic lupus erythematosus between male and female Korean patients. Methods: A retrospective analysis was performed at a single tertiary hospital from August 1994 to May 2010. Male patients were matched with two to three female patients based on age and disease duration. Organ damage was assessed using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index (SLICC/ACR DI). Results: Fifty-three male patients were compared with 150 female patients. Renal disorders were found more frequently in male patients at disease onset (p < 0.001); the adjusted odds ratio (OR) demonstrated a significant sex preponderance for renal manifestations (OR, 3.26; 95% confidence interval [CI], 1.62 to 6.57). Diffuse proliferative lupus nephritis and end-stage renal disease requiring dialysis during the disease course were more prevalent in male patients (p = 0.025 and p < 0.001, respectively). The risk for requiring long-term dialysis was significantly higher in male than in female patients (OR, 4.02; 95% CI, 1.07 to 15.06), as was the mean SLICC/ACR DI ($1.55{\pm}1.35$ vs. $1.02{\pm}1.57$, respectively; p = 0.028). Conclusions: Our data demonstrate that Korean patients with lupus have characteristics similar to those of cohorts reported previously. Male patients had significantly higher incidences of renal manifestations and organ damage.