Clinical features of re-emerging hepatitis A: an analysis of patients hospitalized during an urban epidemic in Korea

From April 2008 to November 2008, many cases of hepatitis A were reported in Seoul and Gyeonggi Province in Korea. Furthermore, the rate of severe or fulminant hepatitis have significantly increased during the latest epidemic (13.4% vs. 5.2%, p=0.044). Therefore, widespread use of vaccine is warranted to reduce the burden of hepatitis A in Korea.

Bacillus-derived poly-γ-glutamic acid attenuates allergic airway inflammation through a Toll-like receptor-4-dependent pathway in a murine model of asthma

BACKGROUND

Asthma is an inflammatory disease of the airways that is mediated by Th2 responses. Poly-γ-glutamic acid (γ-PGA) is an extracellular polymeric compound that is synthesized by Bacillus cells. Previously, we found that γ-PGA promoted Th1 cell development in a manner dependent on antigen-presenting cells, but inhibited Th2 cell development.

OBJECTIVE

To investigate the effect of γ-PGA on dendritic cells (DCs), and its potential for treating Th2-mediated allergic asthma.

METHODS

Wild-type, Toll-like receptor (TLR)-2 deficient, and TLR-4-defective mice were used. DCs derived from the bone marrow and extracted from the lung were stimulated with γ-PGA and assayed for the expression of signalling molecules, costimulatory molecules, and cytokines. Mice were sensitized and challenged with ovalbumin (OVA) to induce asthma. They were repeatedly injected intranasally with γ-PGA before and during the challenge period, and inflammation and structural remodelling of the airways were examined.

RESULTS

γ-PGA selectively signalled conventional DCs to activate NF-κB and mitogen-activated protein kinase, leading to the up-regulation of CD86, CD40, and IL-12, but not IL-10 and IL-6. These effects of γ-PGA were dependent on TLR-4 and independent of TLR-2. Importantly, the intranasal administration of γ-PGA to OVA-sensitized/challenged mice reduced the airway hyperresponsiveness and allergic inflammation such as leucocyte influx, goblet cell hyperplasia, eosinophilia, and Th2 cytokine production. In addition to lowered IgE titres, the treatment of mice with γ-PGA significantly reduced the multiplication and Th2 polarization of mediastinal lymph node T cells upon allergen-specific restimulation. These anti-asthmatic effects of γ-PGA were also abolished in TLR-4-defective mice.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data indicate that γ-PGA activates DCs to favour Th1 cell induction through a TLR-4-dependent pathway and alleviates pathologic symptoms in a Th2-biased asthmatic model. These findings highlight the potential of γ-PGA for the treatment of asthma and other allergic disease in which Th2 polarization plays an important role.

Therapeutic efficacy of chloroquine in Plasmodium vivax and the pvmdr1 polymorphisms in the Republic of Korea under mass chemoprophylaxis

Chemoprophylaxis with hydroxychloroquine (HCQ) and primaquine has been used in the Republic of Korea (ROK) Army since 1997. It may facilitate the development of chloroquine (CQ)-resistant strains of Plasmodium vivax. We investigated the therapeutic efficacy of HCQ and the pvmdr1 gene polymorphisms in P. vivax. From June to September 2006, 102 soldiers with vivax malaria near the demilitarized zone in Gyeonggi-do, ROK, were enrolled in the study. We determined the status of compliance of chemoprophylaxis. In 85 patients, therapeutic efficacy was monitored 28 days after standard HCQ treatment; 66 (64.7%) of 102 malaria patients had taken all chemoprolaxis with HCQ. In all patients enrolled in the therapeutic efficacy monitoring, parasitemia had not been observed since 3 days after standard HCQ treatment. However, the ubiquitous presence of the F1076L mutation of the pvmdr1 was observed. There was no evidence that the F1076L mutation of pvmdr1 could contribute to failure of HCQ treatment.

Immunotherapeutic restoration in HIV-infected individuals

While the development of combined active antiretroviral therapy (cART) has dramatically improved life expectancies and quality of life in HIV-infected individuals, long-term clinical problems, such as metabolic complications, remain important constraints of life-long cART. Complete immune restoration using only cART is normally unattainable even in cases of sufficient plasma viral suppression. The need for immunologic adjuncts that complement cART remains, because while cART alone may result in the complete recovery of peripheral net CD4+ T lymphocytes, it may not affect the reservoir of HIV-infected cells. Here, we review current immunotherapies for HIV infection, with a particular emphasis on recent advances in cytokine therapies, therapeutic immunization, monoclonal antibodies, immune-modulating drugs, nanotechnology-based approaches and radioimmunotherapy.

Steroid withdrawal in adult liver transplantation: occurrence at a single center

BACKGROUNDS

Steroids are the predominant immunosuppressive agent used after liver transplantation even though patients may experience steroid-related side effects.

AIMS

The objective of this study was to determine whether steroid use influenced the outcomes of liver transplantations.

METHODS

Three hundred forty-four adult patients underwent liver transplantation between May 2002 and December 2007. We reviewed the medical records of these patients, excluding those younger than 18 years old or those who died within the first month. The protocol withdrawal group (group 1) ceased steroid use within 5 months after transplantation, while the late withdrawal group (group 2) continued steroid use beyond this 5-month posttransplantation period.

RESULTS

All patients were classified according to the onset of steroid withdrawal (group 1: n = 243; group 2: n = 99). The incidences of biopsy-confirmed and treated acute rejection episodes (ARE) at 12 and 24 months posttransplantation were 7.8% and 12.3% in group 1, but 25.3% and 27.3% in group 2, respectively (P = .001). The incidence of hepatitis B virus (HBV) recurrence in group 2 was higher than that in group 1 (P = .007). The HBV-free survival rates at 1 and 2 years posttransplantation were 99.0% and 97.1% in group 1 and 96.1% and 92.1% in group 2, respectively. New-onset diabetes, avascular necrosis of the femoral head, corticosteroid-resistant ARE, hepatocellular carcinoma recurrence, as well as graft and patient survivals did not differ between the two groups.

CONCLUSIONS

Acute rejection episodes and HBV recurrence occurred less frequently when steroids were discontinued within 5 months after liver transplantation.

Antimicrobial resistance of enterococci isolated from mastitic bovine milk samples in Korea

The aim of this study was to determine the antimicrobial resistance of various species of enterococci isolated from mastitic bovine milk samples. A total of 105 enterococci isolates were examined: Enterococcus faecalis (n = 47), Enterococcus faecium (n = 39), Enterococcus gallinarum (n = 6), Enterococcus avium (n = 6), Enterococcus hirae (n = 5) and Enterococcus durans (n = 2). All the isolates were susceptible to ampicillin, gentamicin and vancomycin, and only a single E. hirae isolate was resistant to ampicillin. In general, the most frequently observed resistance among the enterococcal isolates was to tetracycline (69.5%), followed by penicillin (64.7%), erythromycin (57.1%) and cephalothin (44.7%). A similar antimicrobial resistance pattern was observed among individual species except E. durans, which exhibited only tetracycline resistance. Resistance observed among isolates of E. hirae and E. gallinarum was almost as high as E. faecium and E. faecalis. Of 105 isolates, only six (5.7%) strains of E. faecium were susceptible to all the antimicrobials tested and about 52% (55/105) showed resistance to more than three antimicrobials. The most common multiple resistance pattern was penicillin, tetracycline and erythromycin, which was observed in 32 of 105 (30.4%) isolates. This study demonstrates that enterococcal isolates belonging to minor species showed antimicrobial resistance rates as high as those of E. faecium and E. faecalis, and that monitoring of antimicrobial resistance should not be restricted only to those two major species.

Novel microcantilever design for versatile mass sensor application

This study presents a new microcantilever design for versatile mass sensor application. The novel comb-type cantilever provides a sensitive microcantilever structure for normal sensor application, and its sensing responses are compared with those of a commercial cantilever. While the comb-type cantilever has a similar total surface area to the commercial cantilever, there is a distinct difference in the design of the regional surface area. The results for a static charge interaction, used to compare the sensitivity of normal sensor applications, show a significant resonant frequency change for the comb-type cantilever when compared with that for the commercial cantilever, indicating the importance of the large surface area in the highly sensitive cantilever region. Thus, a schematic structure of a microcantilever for fabricating a highly sensitive mass sensor is proposed.

Molecular inflammation as an underlying mechanism of the aging process and age-related diseases

Aging is a biological process characterized by time-dependent functional declines that are influenced by changes in redox status and by oxidative stress-induced inflammatory reactions. An organism's pro-inflammatory status may underlie the aging process and age-related diseases. In this review, we explore the molecular basis of low-grade, unresolved, subclinical inflammation as a major risk factor for exacerbating the aging process and age-related diseases. We focus on the redox-sensitive transcription factors, NF-κB and FOXO, which play essential roles in the expression of pro-inflammatory mediators and anti-oxidant enzymes, respectively. Major players in molecular inflammation are discussed with respect to the age-related up-regulation of pro-inflammatory cytokines and adhesion molecules, cyclo-oxygenase-2, lipoxygenase, and inducible nitric oxide synthase. The molecular inflammation hypothesis proposed by our laboratory is briefly described to give further molecular insights into the intricate interplay among redox balance, pro-inflammatory gene activation, and chronic age-related inflammatory diseases. The final section discusses calorie restriction as an aging-retarding intervention that also exhibits extraordinarily effective anti-inflammatory activity by modulating GSH redox, NF-κB, SIRT1, PPARs, and FOXOs.

Hard X-ray microbeam lithography using a Fresnel zone plate with a long focal length

Focused hard X-ray microbeams for use in X-ray nanolithography have been investigated. A 7.5 keV X-ray beam generated at an undulator was focused to about 3 µm using a Fresnel zone plate fabricated on silicon. The focused X-ray beam retains a high degree of collimation owing to the long focal length of the zone plate, which greatly facilitates hard X-ray nanoscale lithography. The focused X-ray microbeam was successfully utilized to fabricate patterns with features as small as 100 nm on a photoresist.

The characteristics of metallo-β-lactamase-producing gram-negative bacilli isolated from sputum and urine: a single center experience in Korea

Metallo-β-lactamase (MBL) production usually results in high-level resistance to most β-lactams, and a rapid spread of MBL producing major gram-negative pathogens is a matter of particular concern worldwide. However, clinical data are scarce and most studies compared MBL producer (MP) with MBL non-producer (MNP) strains which included carbapenem susceptible isolates. Therefore, we collected clinical data of patients in whom imipenem-nonsusceptible Pseudomonas aeruginosa (PA) and Acinetobacter baumannii (AB) were isolated from sputum or urine, and investigated MBL production and the risk factors related with MBL acquisition. The antimicrobial susceptibility patterns were also compared between MPs and imipenem-nonsusceptible MNPs (INMNP). Among the 176 imipenem-nonsusceptible isolates, 12 MPs (6.8%) were identified. There was no identifiable risk factor that contributed to the acquisition of MPs when compared to INMNPs, and case-fatalities were not different between the two groups. The percentage of susceptible isolates was higher among MPs for piperacilin/tazobactam and fluoroquinolones while that of ceftazidime was higher in INMNPs (p < 0.05). As regards to aztreonam, which has been known to be a uniquely stable β-lactam against MBLs, susceptibility was preserved in only two isolates (16.7%) among MPs, and was not higher than that of INMNPs (23.2%). In conclusion, the contribution of MBLs to imipenem non-susceptibility in PA/ABs isolated from sputum and urine was relatively limited, and there was no significant risk factor associated with acquisition of MPs compared with INMNPs. However, limited susceptibility to aztreonam implies that MPs may hold additional resistance mechanisms, such as extended spectrum β-lactamases, AmpC β-lactamases, or other non-enzymatic mechanisms.

Lysophosphatidic acid augments human hepatocellular carcinoma cell invasion through LPA1 receptor and MMP-9 expression

Lysophosphatidic acid (LPA), produced extracellularly by autotaxin (ATX), has diverse biological activities implicated in tumor initiation and progression, including increasing cell survival, angiogenesis, invasion and metastasis. ATX, LPA and the matrix metalloproteinase (MMP)-9 have all been implicated in hepatocellular carcinoma (HCC) invasion and metastasis. We, thus sought to determine whether ATX with subsequent LPA production and action, including induction of MMP-9 could provide a unifying mechanism. ATX transcripts and LPA receptor type 1 (LPA1) protein are elevated in HCC compared with normal tissues. Silencing or pharmacological inhibition of LPA1 significantly attenuated LPA-induced MMP-9 expression and HCC cell invasion. Further, reducing MMP-9 activity or expression significantly inhibits LPA-induced HCC cell invasion, demonstrating that MMP-9 is downstream of LPA1. Inhibition of phosphoinositide-3 kinase (PI3K) signaling or dominant-negative mutants of protein kinase Cδ and p38 mitogen-activated protein kinase (MAPK) abrogated LPA-induced MMP-9 expression and subsequent invasion. We thus demonstrate a mechanistic cascade of ATX-producing LPA with LPA activating LPA1 and inducing MMP-9 through coordinate activation of the PI3K and the p38 MPAK signaling cascades, providing novel biomarkers and potential therapeutic targets for HCC.

Risk factors for device-associated infection related to organisational characteristics of intensive care units: findings from the Korean Nosocomial Infections Surveillance System

Device-associated infections (DAIs) have been the major causes of morbidity and mortality of patients in intensive care units (ICUs). This study evaluated the risk factors for DAIs in ICUs. Ninety-six medical or surgical ICUs of 56 hospitals participated in the Korean Nosocomial Infections Surveillance System between July 2007 and June 2008. The occurrence of catheter-associated urinary tract infection (CAUTI), central line-associated bloodstream infection (CABSI), and ventilator-associated pneumonia (VAP) were monitored and DAI rates were calculated. Data associated with ICU characteristics were collected and Poisson regression was used for statistical analysis. Rates of CAUTI, CABSI, and VAP were 3.87 per 1000 urinary catheter days, 2.23 per 1000 central line days, and 1.89 per 1000 mechanical ventilator days, respectively. Rates of CAUTI were higher in ICUs in Seoul (P=0.032) and ICUs of major teaching hospitals (P=0.010). The ICUs of university-affiliated hospitals showed lower CAUTI rates (P=0.013). CABSI rates were higher in Seoul (P=0.001) and in medical ICUs (P=0.026). VAP rates were lower in ICUs of hospitals with more than 900 beds compared with hospitals with 400-699 beds (P=0.026). VAP rates were higher in surgical ICUs (P<0.0001) and increased 1.13-fold with each 100-unit increase in beds per infection control professional (P=0.003). The organisational and institutional characteristics of ICUs may influence DAI rates and there is a need for improvement in the incidence of VAP, CAUTI or CABSI.

The effect of cytomegalovirus antigenemia titer on the efficacy of preemptive therapy for the prevention of cytomegalovirus disease after kidney transplantation

There is some controversy regarding the exact cytomegalovirus (CMV) antigenemia titer that should be used as a guideline for preemptive anti-CMV therapy. We performed 634 consecutive kidney transplantations between January 2000 and June 2007. Preemptive therapy employed intravenous gancyclovir treatment when the CMV antigenemia titer was >or=50/4x10(5) leukocytes after kidney transplantation. The 634 recipients were allocated into 2 groups according to the peak CMV antegenemia: group A, CMV antigenemia titer<50/4x10(5) (n=550); and group B, >or=50/40x10(5) (n=84). Among the 634 recipients, 264 were positive for CMV antigenemia, and 61 developed symptomatic CMV infections. The incidence of symptomatic CMV infections in group B was significantly higher than in group A. Two cases in both groups developed tissue-proven CMV disease: group A CMV colitis and CMV nephritis, and group B, 2 cases of CMV colitis. Graft and patient survival rates in groups A and B at 5 years posttransplantation were not different. The authors concluded that a CMV antigenemia titer of >or=50/4x10(5) leukocytes can be considered an appropriate guideline for preemptive anti-CMV therapy.

Patients with unresectable hepatocellular carcinoma beyond Milan criteria: should we perform transarterial chemoembolization or liver transplantation?

Patients with unresectable, beyond Milan criteria, hepatocellular carcinoma (HCC) invariably undergo palliative transarterial chemoembolization (TACE). The aim of this study was to compare the outcomes of conventional TACE versus liver transplantation (LT) in unresectable (beyond Milan criteria) HCC. Twelve patients underwent LT and 86 TACE for unresectable, beyond Milan criteria HCC. The inclusion criteria were a single tumor<or=6.5 cm or <or=5 tumors and all tumors<or=5 cm based on initial radiologic findings. We excluded patients with double primary cancers, age>60 years, vascular invasion, or extrahepatic spread. Survival rates were calculated using the Kaplan-Meier method. Multivariate analysis showed that TACE was a prognostic factor for survival (hazard ratio, 16.66, P=.000). The LT group showed significantly better survival than the TACE cohort. Two cases (16.7%) in the LT group recurred at a median time of 13.5 months. Survival rates at 1, 3, and 5 years were 100%, 88.9%, and 76.2% in the LT group, and 85.6%, 45.6%, and 21.4% in the TACE group, respectively. Patients with unresectable, beyond Milan criteria HCC should be given the option to receive LDLT, because LT offers a significantly better likelihood of survival than TACE.

Living donor liver transplantation in Budd-Chiari syndrome: a single-center experience

Budd-Chiari syndrome (BCS), which is characterized by hepatic venous outflow obstruction due to occlusion of the major hepatic vein and/or the inferior vena cava (IVC), is rare. Traditionally, a caval resection is advocated for these patients; however, such a maneuver renders living donor liver transplantation (LDLT) impossible. We encountered BCS in 4/377 LDLT patients during a 5-year period (January 2003 to December 2007). This report examine the various surgical modifications in these 4 patients, who underwent to LDLT for BCS. Resection of right hepatic vein (RHV) with an adjacent fibrotic part of the IVC with direct anastomosis of the graft RHV to the IVC was performed in 2 patients. One patient underwent retrohepatic IVC excision and reconstruction with a cryopreserved autologous IVC graft. The fourth patient, with a preexisting mesoatrial shunt for BCS, underwent conversion of this to a RHV atrial shunt. Graft and patient survivals were 100%. There were few complications in either donors or recipients. LDLT for BCS can be performed safely with adequate venous drainage techniques and with anticoagulant therapy and good follow-up for early diagnosis and treatment of recurrence leading to excellent long-term results.

Risk factors for posttransplant lymphoproliferative disorder in pediatric liver transplant recipients with cytomegalovirus antigenemia

Epstein-Barr virus (EBV) infections, associated with posttransplant lymphoproliferative disorder (PTLD) are known to develop in cytomegalovirus (CMV)-infected transplant recipients due to the indirect effects of CMV. This study evaluated risk factors for PTLD among pediatric liver transplant recipients with CMV infections. We reviewed the medical records of 119 patients<or=18 years old who underwent liver transplantation between September 1996 and April 2009. Sixty-six subjects (55.5%) displayed CMV antigenemia during the study period; 15 (12.6%) developed PTLD. Of these, 10 developed PTLD after CMV antigenemia. The other patients (n=5) were excluded due to negative CMV antigenemia. The incidence of PTLD influenced by CMV infection was not significantly different from the incidence of PTLD without underlying CMV (P=.258). There were no differences in age, gender, antiviral prophylaxis, type of liver transplantation, or acute rejection episodes in the incidence of between patients with versus without PTLD. EBV but not CMV high-risk groups were a predictor for the development of PTLD (P=.035). CMV syndrome, tissue-invasive CMV disease, and CMV peak titer were not associated with an increased risk of PTLD. The primary risk factor for PTLD was EBV high-risk patients (donor positive/recipient negative). CMV disease was not associated with PTLD in pediatric liver transplant recipients with CMV infections.

New cfiA variant and novel insertion sequence elements in carbapenem-resistant Bacteroides fragilis isolates from Korea

Of 276 nonduplicate Bacteroides fragilis clinical isolates recovered from 1997 to 2004, 3 were resistant to carbapenem. cepA and cfiA alleles were detected by polymerase chain reaction in 240 (87.0%) and 11 (4.0%) of the isolates, respectively. Insertion sequence (IS) elements were found only in the 3 carbapenem-resistant B. fragilis isolates, which produced metallo-beta-lactamase at a level detectable by UV spectrophotometry. Sequence analysis showed 1 new cfiA variant, cfiA(11), and 2 novel IS elements. The cfiA(11) gene revealed 5 amino acid substitutions compared to cfiA, with 97.6% amino acid identity. The transposase, terminal inverted repeat sequence, and target site duplication sequence of the 2 novel IS elements were unique. This study reconfirmed the correlation between ISs and carbapenem resistance in B. fragilis.

Novel anti-apoptotic mechanism of A20 through targeting ASK1 to suppress TNF-induced JNK activation

The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis.

Disseminated Mycobacterium kansasii infection associated with skin lesions: a case report and comprehensive review of the literature

Mycobacteruim kansasii occasionally causes disseminated infection with poor outcome in immunocompromised patients. We report the first case of disseminated M. kansasii infection associated with multiple skin lesions in a 48-yr-old male with myelodysplastic syndrome. The patient continuously had taken glucocorticoid during 21 months and had multiple skin lesions developed before 9 months without complete resolution until admission. Skin and mediastinoscopic paratracheal lymph node (LN) biopsies showed necrotizing granuloma with many acid-fast bacilli. M. kansasii was cultured from skin, sputum, and paratracheal LNs. The patient had been treated successfully with isoniazid, rifampin, ethmabutol, and clarithromycin, but died due to small bowel obstruction. Our case emphasizes that chronic skin lesions can lead to severe, disseminated M. kansasii infection in an immunocompromised patient. All available cases of disseminated M. kansasii infection in non HIV-infected patients reported since 1953 are comprehensively reviewed.

Comparison of genotypic resistance mutations in treatment-naive HIV type 1-infected patients in Korea and China

Seventy-six treatment-naive human immunodeficiency virus (HIV)-1-infected patients were recruited from Korea and China to evaluate transmitted drug resistance (TDR). Although no major TDR was observed within the study population, some resistance-associated mutations in the reverse transcriptase region were observed (V118I 9.2%, V179D 7.9%). The frequencies of resistance-associated mutations in NNRTI (V179D) and PI minor mutations were higher in Korean patients compared with Chinese patients (13.6% vs. 0%, 45.5% vs. 12.5%, p < 0.05). Although unique clustering was observed in phylogenetic analyses according to geographic sources, cautious monitoring is recommended due to increasing TDR reports in this area where the population shares close geographic and cultural aspects.

Prevalence of and clinical factors associated with lipoatrophy in HIV-infected Koreans receiving highly active antiretroviral therapy

Lipoatrophy is the long-term adverse effects developed in human immunodeficiency virus (HIV)-1-infected subjects receiving highly active antiretroviral therapy (HAART). This cross-sectional study aimed to evaluate the prevalence of and clinical factors associated with lipoatrophy in HIV-infected Koreans receiving HAART for more than 6 months. Lipoatrophy was diagnosed by concordance between physical examination and history taking performed by a single physician. Various covariates were examined, including diabetes mellitus (DM), lipid profiles after HAART, and HAART regimen and duration. Among total 144 patients (6 females and 138 males), 35 patients (24.3%) were diagnosed with lipoatrophy. The prevalence of lipoatrophy was significantly higher in females than that in males [83.3% (5/6) vs. 21.7% (30/138), p = 0.010] and higher in patients with DM than patients without DM [66.7% (4/6 DM) vs. 22.5% (31/138 non-DM), p = 0.030], or in patients with high total cholesterol levels than patients with low total cholesterol levels [31.9% (23/72 patients with high cholesterol) vs. 16.7% (12/72 patients with low cholesterol), p = 0.035]. Moreover, patients with stavudine treatment history (> 12 months) had a higher prevalence of lipoatrophy than patients who never received stavudine [50.0% (15/30) vs. 16.5% (17/103), p < 0.001]. In the multivariate logistic analysis, stavudine treatment for > 12 months (OR, 3.67; p = 0.011) and being female (OR, 24.93; p = 0.009) are independently associated with lipoatrophy. In conclusion, the prevalence of lipoatrophy in HIV-infected Koreans receiving HAART is not uncommon. Limited use of stavudine and regular monitoring are warranted to reduce lipoatrophy.

Antiretroviral genotypic resistance mutations in HIV-1 infected Korean patients with virologic failure

Resistance assays are useful in guiding decisions for patients experiencing virologic failure (VF) during highly-active antiretroviral therapy (HAART). We investigated antiretroviral resistance mutations in 41 Korean human immunodeficiency virus type 1 (HIV-1) infected patients with VF and observed immunologic/virologic response 6 months after HAART regimen change. Mean HAART duration prior to resistance assay was 45.3+/-27.5 months and commonly prescribed HAART regimens were zidovudine/lamivudine/nelfinavir (22.0%) and zidovudine/lamivudine/efavirenz (19.5%). Forty patients (97.6%) revealed intermediate to high-level resistance to equal or more than 2 antiretroviral drugs among prescribed HAART regimen. M184V/I mutation was observed in 36 patients (87.7%) followed by T215Y/F (41.5%) and M46I/L (34%). Six months after resistance assay and HAART regimen change, median CD4+ T cell count increased from 168 cells/microL (interquartile range [IQR], 62-253) to 276 cells/microL (IQR, 153-381) and log viral load decreased from 4.65 copies/mL (IQR, 4.18-5.00) to 1.91 copies/mL (IQR, 1.10-3.60) (P<0.001 for both values). The number of patients who accomplished viral load <400 copies/mL was 26 (63.4%) at 6 months follow-up. In conclusion, many Korean HIV-1 infected patients with VF are harboring strains with multiple resistance mutations and immunologic/virologic parameters are improved significantly after genotypic resistance assay and HAART regimen change.

Serum retinol-binding protein 4 correlates with obesity, insulin resistance, and dyslipidemia in HIV-infected subjects receiving highly active antiretroviral therapy

Highly active antiretroviral therapy (HAART) contributes to the development of metabolic complications including dyslipidemia, insulin resistance (IR), and lipodystrophy (LD). Recent studies reported that retinol-binding protein 4 (RBP4) is associated with IR, dyslipidemia, and obesity in non-HIV-infected populations. The aim of this study was to evaluate the associations between RBP4 and LD or metabolic abnormalities in HIV-infected subjects receiving HAART. We performed a cross-sectional study with 113 HIV-infected subjects receiving HAART for more than 6 months. Body composition and abdominal fat were measured by bioelectrical impedance analysis and ultrasonography, and fasting serum RBP4 was measured by enzyme-linked immunosorbent assay. Retinol-binding protein 4 levels in subjects with LD were similar to those without LD (P = .839). Retinol-binding protein 4 had significantly positive correlations with waist circumference (r = 0.298, P = .002), waist-to-hip ratio (r = 0.336, P = .001), body mass index (r = 0.310, P = .002), total body fat mass (r = 0.323, P = .001), total cholesterol (r = 0.188, P = .048), log (triglyceride) (r = 0.269, P = .004), and log (homeostasis model assessment of IR) (r = 0.207, P = .036), and negative correlations with quantitative insulin sensitivity check index (r = -0.209, P = .034) after adjustment for age and sex. In stepwise multivariate linear regression analysis, waist-to-hip ratio was the most significant independent predictor of increased RBP4 (standardized beta = .351, P = .001). These results suggest that serum RBP4 is associated with obesity, IR, and dyslipidemia in HIV-infected subjects receiving HAART.

DNA microarray-based identification of bacterial and fungal pathogens in bloodstream infections

The accurate and rapid identification of pathogens in blood is a major challenge in clinical pathogen diagnostics because of the high mortality of sepsis. Here we report the development of DNA microarray for the identification of pathogens causing bloodstream infections. Species-specific and bacteria- and fungi-broad-ranged probes were designed to identify 50 bacteria and 7 fungi. The specificities and sensitivities of the selected probes were successfully validated by applying reference strains. To assess the performance of the DNA microarray in a clinical setting, blind tests were performed using 112 blood culture specimens that showed preliminary presence of pathogenic microorganisms by culture-based method, resulting in the correct identification of pathogens in 104 samples showing the sensitivity of 93%. In addition, closely-related species could be discriminated by the distinct hybridization patterns. This DNA microarray-based pathogen diagnosis takes approximately 10 h starting from a positive blood culture, considerably reducing time required to sufficiently identify pathogens by subsequent agar-culture and biochemical tests which requires altogether at least 1-3 days. Also, the amount of sample required for the identification of pathogens is much less than that required for biochemical assays. Thus, the DNA microarray reported here should be useful for the effective identification of microbial pathogens in blood cultures from septicemic patients.

Blood stream infections by Candida glabrata and Candida krusei: a single-center experience

BACKGROUND/AIMS

The increasing incidence of Candida glabrata and Candida krusei infections is a significant problem because they are generally more resistant to fluconazole. We compared the risk factors associated with C. glabrata and C. krusei fungemia with Candida albicans fungemia and examined the clinical manifestations and prognostic factors associated with candidemia.

METHODS

We retrospectively reviewed demographic data, risk factors, clinical manifestations, and outcomes associated with C. glabrata and C. krusei fungemia at a tertiary-care teaching hospital during a 10-years period from 1997 to 2006.

RESULTS

During the study period, there were 497 fungemia episodes. C. glabrata fungemia accounted for 23 episodes and C. krusei fungemia accounted for 8. Complete medical records were available for 27 of these episodes and form the basis of this study. Compared to 54 episodes of C. albicans fungemia, renal insufficiency and prior fluconazole prophylaxis were associated with development of C. glabrata or C. krusei fungemia. The overall mortality was 67%. The fungemia-related mortality of C. glabrata and C. krusei was higher than that of C. albicans (52 vs. 26%, p=0.021). Empirical antifungal therapy did not decrease the crude mortality. Multiple logistic regression analysis showed that high APACHE II scores, catheter maintenance, and shock were independently associated with an increased risk of death.

CONCLUSIONS

Renal insufficiency and prior fluconazole prophylaxis were associated with the development of C. glabrata or C. krusei fungemia. Fungemia-related mortality of C. glabrata or C. krusei was higher than that of C. albicans. Outcomes appeared to be related to catheter removal, APACHE II scores, and shock.

Pharmacokinetics of indinavir in Koreans and Caucasians

We evaluated whether the pharmacokinetic parameters of indinavir differ in Koreans and Caucasians. Indinavir was administered orally to 8 healthy Koreans and 4 healthy Caucasians, and plasma indinavir levels were quantified by high performance liquid chromatography. No significant differences were observed in terms of its pharmacokinetic parameters; however, the AUC difference between the 2 groups may be significant for larger sample sizes.

Incidence and risk factors of infection in a single cohort of 110 adults with systemic lupus erythematosus

Infection is a major cause of mortality in patients with systemic lupus erythematosus (SLE). This study describes infectious complications in SLE patients and analyzes the risk factors for infection at the time of SLE diagnosis and during the course of SLE in a case-control study. Of 110 patients enrolled, 42 (38%) had at least 1 episode of infectious disease. The incidence of infectious disease was 4.4/100 patient-years (py) with a total follow-up duration of 954 y. In multivariate analysis, independent predictors of infection at the time of SLE diagnosis were an SLE disease activity index (SLEDAI) > 12 (p = 0.01), C3 levels < 90 mg/dl (p = 0.01) and positive anti-ds DNA antibodies (p < 0.01). Frequent flare-ups (p = 0.04) and follow-up duration > or =8 y (p = 0.023) were also significant risk factors for infectious diseases. It is mandatory to closely observe SLE patients with risk factors for developing infectious diseases.

Associations of the variation in the porcine myogenin gene with muscle fibre characteristics, lean meat production and meat quality traits

Pig breeding is aimed at improving lean meat production ability as well as meat quality, and muscle fibre characteristics may be important for enhancing these traits. Therefore, new molecular markers have been demanded for selecting lean meat production ability and meat quality in live animals. Myogenin belongs to the MyoD gene family, and is a candidate gene responsible for muscle fibre characteristics. We identified a new single nucleotide polymorphism (SNP) site in the 5' upstream region of the myogenin gene (nucleotides C and T). A total of 252 pigs of three breeds were genotyped by polymerase chain reaction-restriction fragment length polymorphism using BspCNI. Additionally, they were genotyped for the previously detected MspI site in the 3'-flanking region (alleles A and B). The CCBB diplotype had the highest frequency over breeds, followed by TCBB and CCAB. The other diplotypes were not found in studied pigs. Association analysis performed for the markers found that the TCBB diplotype has desirable effects on the total number of fibres (p < 0.002), fibre cross-sectional area (p < 0.06), and loin eye area (p < 0.001) than the other diplotypes. Moreover, the diplotype had the highest muscle pH value (p < 0.07) and all meat quality traits were near the upper limit of the normal range as a reddish pink, firm and non-exudative (RFN) pork. Therefore, we suggest that selection for the myogenin diplotypes could improve total muscle fibre number, size and lean meat production ability with good meat quality.

Diagnosis and species identification of mycobacterial infections by polymerase chain reaction-restriction fragment length polymorphism analysis of sterile body fluids

BACKGROUND/AIMS

The development of effective, accurate, and rapid diagnostic methods for Mycobacterium infection and mycobacterial species identification is required. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) is an easy, rapid and inexpensive technique for identifying Mycobacterium spp.

METHODS

We performed PCR-RFLP to detect and identify Mycobacterium spp. from 10 sterile body fluids, including ascites, cerebrospinal fluid, pleural fluid, synovial fluid, and peritoneal dialysis fluid. Clinical samples were collected from patients with diagnoses of definite, probable or suspected mycobacterial infection. The conserved RNA polymerase genes of Mycobacterium spp. were amplified by PCR.

RESULTS

The amplified 360-bp region of rpoB was digested with the restriction enzyme MspI or HaeIII. The PCR-RFLP results for the clinical samples were identical to those for M. tuberculosis, M. fortuitum, M. intracellulare, and M. avium. In addition, the results of the PCR-RFLP were identical to those obtained by DNA sequencing.

CONCLUSIONS

PCR-RFLP analysis of sterile body fluids may be a useful method for the diagnosis of mycobacterial infections and for the differentiation of mycobacterial species.

High-throughput identification of clinically important bacterial pathogens using DNA microarray

Rapid and accurate detection of pathogenic bacteria is important for the treatment of patients with suitable antibiotics. Here we report the development of a diagnostic DNA microarray for the high-throughput identification of 39 pathogenic bacteria selected based on their high prevalence rate and/or difficulty of cultivation. The 23S ribosomal DNA and 16S-23S rDNA intergenic spacer region were used as target DNAs for pathogen detection. Universal- and species-specific probes were designed based on the unique and common sites within the target DNA sequences. New target DNA sequences were determined for the detection of 19 bacterial pathogens. The usefulness of the designed probes was validated using 39 reference bacteria and also with 515 clinical isolates from various clinical samples including blood, stool, pus, sputum, urine and cerebrospinal fluid. The DNA microarray developed in this study allowed efficient detection of bacterial pathogens with the specificities of 100%. The sensitivities were 100% as well except for the two pathogens, Enterobacter cloacae (75%) and Enterococcus faecium (85%). These results suggest that the DNA microarray-based assay developed in this study outperforms current diagnostic systems with respect to sensitivity, specificity, and high-throughput detection, and thus should be useful in pathogen diagnosis in the clinical setting.

5,7-dihydroxy-3,4,6-trimethoxyflavone inhibits the inflammatory effects induced by Bacteroides fragilis enterotoxin via dissociating the complex of heat shock protein 90 and I kappaB alpha and I kappaB kinase-gamma in intestinal epithelial cell culture

Enterotoxin produced by enterotoxigenic Bacteroides fragilis (BFT) has been associated with mucosal inflammation and diarrhoeal diseases. In this study, the anti-inflammatory molecular mechanism of 5,7-dihydroxy-3,4,6-trimethoxyflavone (eupatilin) was characterized in an HT-29 intestinal epithelial cell line stimulated with BFT. Pre-treatment of HT-29 cells with eupatilin decreased the production significantly of both interleukin (IL)-8 and prostaglandin E(2) induced by BFT in a dose-dependent manner. BFT-activated nuclear factor-kappaB (NF-kappaB) signals in HT-29 cells and pretreatment with eupatilin suppressed NF-kappaB activation that resulted in the significant inhibition of IL-8 and cyclo-oxygenase-2 expression. BFT-induced phosphorylation of both I kappaB alpha and I kappaB kinase (IKK) signals was prevented in eupatilin-pretreated HT-29 cells. Transfection of siRNA for IKK-alpha and IKK-beta decreased the production of IL-8 and prostaglandin E(2); however, the transfection of IKK-beta siRNA showed a more significant reduction of BFT-induced I kappaB alpha phosphorylation compared with that of IKK-alpha siRNA. In addition, herbimycin A, a specific inhibitor of heat shock protein 90 (Hsp90), decreased the BFT-induced activation of IKK and NF-kappaB, suggesting that Hsp90 is associated with a pathway of IKK-NF-kappaB-IL-8/cyclo-oxygenase-2 gene signalling. Furthermore, eupatilin dissociated the complex between Hsp90 and IKK-gamma in BFT-stimulated HT-29 cells. These results suggest that eupatilin can suppress the NF-kappaB signalling pathway by targeting the Hsp90-IKK-gamma complex in intestinal epithelial cells and may attenuate BFT-induced inflammatory responses.

Low prevalence of drug-resistant HIV-1 in patients newly diagnosed with early stage of HIV infection in Korea

There is a concern that the widespread use of antiretroviral drugs to treat HIV infections may result in the increased transmission of a drug-resistant virus. Drug resistance testing before initiating treatment among newly diagnosed HIV patients is helpful in the design of initial regimens. Although HIV infected patients have been increasing in Korea, the transmission rate of drug-resistant HIV is unknown. The aim of this study was to determine the prevalence of antiretroviral drug resistance-associated mutations in patients newly diagnosed as early stage of HIV infection in Korea. We defined patients with early HIV infections as those with confirmed diagnoses who had an indeterminate Western blot. We performed genotypic resistance testing in 66 HIV-1 subjects at an early HIV infection stage who were identified between March 2002 and June 2005. Two of the 66 subjects with early HIV infections showed major mutations associated with resistance. Major mutations by themselves reduce susceptibility to one or more drugs and occur commonly during virological failure. Minor mutations have little or no effect on susceptibility and occur only after other drug-resistance mutations. The resistant mutation of reverse-transcriptase gene was found at E44D, and the major resistant mutation of protease gene was found at M46L. Minor protease resistance mutations were seen in 52 cases. Genetic subtype analysis revealed that all subjects were infected with HIV-1 subtype B. In conclusion, the prevalence of drug-resistant HIV-1 in patients newly diagnosed with HIV in its early infection stage is not high in Korea.

Clinical features and prognostic factors of anaerobic infections: a 7-year retrospective study

BACKGROUND/AIMS

Risk factors for mortality resulting from anaerobic infection are incompletely defined. The clinical significance of a broad range of pathogenic obligate anaerobic organisms was examined, and factors independently associated with mortality were identified in patients with clinically significant anaerobic infections.

METHODS

The medical records of 1,050 patients with anaerobic infections were retrospectively reviewed at Severance Hospital in Seoul, Korea.

RESULTS

The mean age of the patients was 54.1+/-16.8 years, and 57.7% were men. Overall, 320 (30.5%) patients with case-defined illness experienced pain at the affected site, and 230 (21.9%) experienced pus flow from lesions. Ten (1.4%) patients presented with shock, and 80.3% of the clinically significant cases were polymicrobial anaerobic infections. The mean number of pathogens, including aerobic and anaerobic bacteria, was 3.7+/-1.0 (minimum 1, maximum 5), and the number of anaerobic organisms was 1.0+/-0.3 in each specimen. The major pathogens by rank were the Bacteroides fragilis group, which accounted for 41.8% of anaerobic infections, followed by Clostridium spp. (11.8%), Prevotella spp. (9.4%), and Peptostreptococcus spp. (8.4%). Escherichia coli (17.5%), Staphylococcus aureus (7.5%), and Klebsiella pneumoniae (7.5%) were common concomitant aerobic organisms. The overall crude mortality rate resulting from anaerobic infection was 29.7%. Among the determining factors associated with mortality, liver disease (p=0.003) and old age (p=0.005) were significant in multivariate analysis.

CONCLUSIONS

Anaerobic infection is polymicrobial and has a significant role in morbidity and mortality. Underlying liver disease was associated with poor prognosis in anaerobic infection.

Factors associated with HIV-1 proviral DNA loads in patients with undetectable plasma RNA load

To evaluate factors associated with human immunodeficiency virus type 1 (HIV-1) proviral DNA load, we conducted a cross-sectional study of 36 chronically HIV-1-infected individuals with undetectable plasma viral RNA. We used real-time polymerase chain reaction to determine the number of HIV-1 proviral DNA copies per 10(6) peripheral blood mononuclear cells. The mean level of plasma viral RNA when the CD4+ T cell count was above 500 cells/microL without highly active antiretroviral therapy (HAART) was significantly associated with proviral DNA load at the time of undetectable plasma HIV RNA with HAART. Strategies to reduce the level of plasma viral RNA when patients' CD4+ T cell counts are above 500 cells/microL without HAART could help reduce HIV-1 proviral DNA load.

[Microorganisms isolated from blood cultures and their antimicrobial susceptibility patterns at a university hospital during 1994-2003]

BACKGROUND

Blood culture is important for the determination of the etiologic agent of bacteremia. Analysis of blood culture results and antimicrobial susceptibility trend can provide clinicians with relevant information for the empirical treatment of patients.

METHODS

The species and antimicrobial susceptibility of the isolates from blood cultures at the Severance Hospital during 1994-2003 were analysed. Blood specimens were cultured for 7 days using tryptic soy broth and thioglycollate medium. Identification of organism was based on conventional methods or commercial kit systems. Antimicrobial susceptibility was tested by a disk diffusion method.

RESULTS

Of 536,916 blood specimens cultured, 24,877 (4.6%) from 13,102 patients were positive. Among the isolates, 93.1% were aerobic or facultative anaerobic bacteria, 3.3% anaerobes, and 3.6% fungi. Escherichia coli was isolated most frequently, followed by Staphylococcus aureus, alpha-hemolytic Streptococcus, Enterococcus spp., and Klebsiella pneumoniae. The proportion of patients with Enterococcus faecium and K. pneumoniae gradually increased during this study. Enterococcus, S. aureus and alpha-hemolytic Streptococcus were frequently isolated from the age group of less than 2 yr. E. coli, Enterococcus spp., K. pneumoniae and S. aureus from the age group of over 50 yr. Oxacillin-resistant S. aureus decreased, whereas vancomycin-resistant E. faecium and imipenemresistant Pseudomonas aeruginosa and Acinetobacter baumannii increased.

CONCLUSIONS

E. coli was the most common cause of bacteremia and S. aureus, alpha-hemolytic Streptococcus, and K. pneumoniae were frequently isolated pathogens. The bacteremia due to Enterococcus, K. pneumoniae, fungi, vancomycin-resistant E. faecium, and imipenem-resistant P. aeruginosa and A. baumannii gradually increased during this period.