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Search Results: 1 - 10 of 28885 matches for " Sang-Oh Lee "
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Current concepts on cytomegalovirus infection after liver transplantation
Sang-Oh Lee, Raymund R Razonable
World Journal of Hepatology , 2010,
Abstract: Cytomegalovirus (CMV) is the most common viral pathogen that negatively impacts on the outcome of liver transplantation. CMV cause febrile illness often accompanied by bone marrow suppression, and in some cases, invades tissues including the transplanted allograft. In addition, CMV has been significantly associated with an increased predisposition to allograft rejection, accelerated hepatitis C recurrence, and other opportunistic infections, as well as reduced overall patient and allograft survival. To negate the adverse effects of CMV on outcome, its prevention, whether through antiviral prophylaxis or preemptive therapy, is regarded as an essential component to the medical management of liver transplant patients. Two recent guidelines have suggested that antiviral prophylaxis or preemptive therapy are similarly effective in preventing CMV disease in modest-risk CMV-seropositive liver transplant recipients, while antiviral prophylaxis is the preferred strategy over preemptive therapy for the prevention of CMV disease in high-risk recipients [CMV-seronegative recipients of liver allografts from CMV-seropositive donors (D+/R-)]. However, antiviral prophylaxis has only delayed the onset of CMV disease in many CMV D+/R- liver transplant recipients, and at least in one study, such occurrence of late-onset primary CMV disease was significantly associated with increased mortality after liver transplantation. Therefore, optimized strategies for prevention are needed, and aggressive treatment of CMV infection and disease should be pursued. The standard treatment of CMV disease consists of intravenous ganciclovir or oral valganciclovir, and if feasible, one should also reduce the degree of immunosuppression. In one recent controlled clinical trial, valganciclovir was found to be as effective and safe as intravenous ganciclovir for the treatment of mild to moderate CMV disease in solid organ (including liver) transplant recipients. In this article, the authors review the current state and the future perspectives of prevention and treatment of CMV disease after liver transplantation.
Acinetobacter baumannii Secretes Cytotoxic Outer Membrane Protein A via Outer Membrane Vesicles
Jong Sook Jin,Sang-Oh Kwon,Dong Chan Moon,Mamata Gurung,Jung Hwa Lee,Seung Il Kim,Je Chul Lee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017027
Abstract: Acinetobacter baumannii is an important nosocomial pathogen that causes a high morbidity and mortality rate in infected patients, but pathogenic mechanisms of this microorganism regarding the secretion and delivery of virulence factors to host cells have not been characterized. Gram-negative bacteria naturally secrete outer membrane vesicles (OMVs) that play a role in the delivery of virulence factors to host cells. A. baumannii has been shown to secrete OMVs when cultured in vitro, but the role of OMVs in A. baumannii pathogenesis is not well elucidated. In the present study, we evaluated the secretion and delivery of virulence factors of A. baumannii to host cells via the OMVs and assessed the cytotoxic activity of outer membrane protein A (AbOmpA) packaged in the OMVs. A. baumannii ATCC 19606T secreted OMVs during in vivo infection as well as in vitro cultures. Potential virulence factors, including AbOmpA and tissue-degrading enzymes, were associated with A. baumannii OMVs. A. baumannii OMVs interacted with lipid rafts in the plasma membranes and then delivered virulence factors to host cells. The OMVs from A. baumannii ATCC 19606T induced apoptosis of host cells, whereas this effect was not detected in the OMVs from the ΔompA mutant, thereby reflecting AbOmpA-dependent host cell death. The N-terminal region of AbOmpA22-170 was responsible for host cell death. In conclusion, the OMV-mediated delivery of virulence factors to host cells may well contribute to pathogenesis during A. baumannii infection.
Activin A induces ovine follicle stimulating hormone beta using -169/-58 bp of its promoter and a simple TATA box
Sang-oh Han, William L Miller
Reproductive Biology and Endocrinology , 2009, DOI: 10.1186/1477-7827-7-66
Abstract: Progressively longer deletions of ovine FSHBLuc were created between -4741/-195 bp. Deletions internal to this region were created also, but replaced with substitute DNA. The ovine FSHB TATA box region (-40/+3 bp) was replaced by thymidine kinase and rat prolactin minimal promoters, and substitutions were made in 3' intron/exon sequences. All constructs were tested for basal and activin A-induced expression in LbetaT2 cells.Successive 5' deletions progressively lowered fold-induction by activin A from 9.5 to zero, but progressively increased basal expression. Replacing deletions with substitute DNA showed no changes in basal expression or fold-induction. Induction by activin A was supported by the minimal rat prolactin promoter (TATA box) but not the thymidine kinase promoter (no TATA box). Replacement mutations in the 3' region did not decrease induction by activin A.The data show that specific ovine FSHB sequences 5' to -175 bp or 3' of the transcription start site are not required for induction by activin A. A minimal TATA box promoter supports induction by activin A, but the sequence between the TATA box and transcription start site seems unimportant.Follicle stimulating hormone (FSH) is made only in pituitary gonadotropes and stimulates gonads for normal reproductive function in females and males [1-3]. Transcription of the gene encoding FSH beta subunit (FSHB) is rate limiting for overall hormone production, and the most potent and influential direct inducer of FSH production is in the activin family [4,5]. Activin A is used to study FSHB regulation in most studies. Significant research has focused on classical Smad activation by activin A and its down-stream signals leading to FSHB expression, but the evidence for Smad involvement with ovine FSHB is not yet clear [6,7].A complementary approach to understanding activin A signaling is to identify promoter sequences required for induction. The standard approach for these studies is to analyze transient expressio
Association of Mannose-Binding Lectin 2 Gene Polymorphisms with Persistent Staphylococcus aureus Bacteremia
Yong Pil Chong, Ki-Ho Park, Eun Sil Kim, Mi-Na Kim, Sung-Han Kim, Sang-Oh Lee, Sang-Ho Choi, Jin-Yong Jeong, Jun Hee Woo, Yang Soo Kim
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0089139
Abstract: Objectives Mannose-binding lectin (MBL) is an important component of innate immunity. Structural and promoter polymorphisms in the MBL2 gene that are responsible for low MBL levels are associated with susceptibility to infectious diseases. The objective of this study was to investigate the association of serum MBL levels and MBL2 polymorphisms with persistent Staphylococcus aureus bacteremia (SAB) in adult Korean patients. Methods We conducted a case-control study nested in a prospective cohort of patients with SAB. The study compared 41 patients with persistent bacteremia (≥7 days) and 46 patients with resolving bacteremia (<3 days). In each subject, we genotyped six single-nucleotide polymorphisms in the promoter region (alleles H/L, X/Y, and P/Q) and exon 1 (alleles A/B, A/C, and A/D) of the MBL2 gene and measured serum MBL concentrations. We also compared MBL2 genotypes between SAB patients and healthy people. Results Patients with persistent bacteremia were significantly more likely to have low/deficient MBL-producing genotypes and resultant low serum MBL levels, than were patients with resolving bacteremia (P = 0.019 and P = 0.012, respectively). Independent risk factors for persistent bacteremia were metastatic infection (adjusted odds ratio [aOR], 34.7; 95% confidence interval [CI], 12.83–196.37; P = 0.003), methicillin resistance (aOR, 4.10; 95% CI, 3.19–29.57; P = 0.025), and low/deficient MBL-producing genotypes (aOR, 7.64; 95% CI, 4.12–63.39; P = 0.003). Such genotypes were significantly more common in patients with persistent bacteremia than in healthy people (OR, 2.09; 95% CI, 1.03–4.26; P = 0.040). Conclusions This is the first demonstration of an association of low MBL levels and MBL2 polymorphisms responsible for low or deficient MBL levels with persistent SAB. A combination of factors, including clinical and microbiological characteristics and host defense factors such as MBL levels, may together contribute to the development of persistent SAB.
Integrin Trafficking and Tumor Progression
Sejeong Shin,Laura Wolgamott,Sang-Oh Yoon
International Journal of Cell Biology , 2012, DOI: 10.1155/2012/516789
Abstract: Integrins are major mediators of cancer cell adhesion to extracellular matrix. Through this interaction, integrins play critical roles in cell migration, invasion, metastasis, and resistance to apoptosis during tumor progression. Recent studies highlight the importance of integrin trafficking, endocytosis and recycling, for the functions of integrins in cancer cells. Understanding the molecular mechanisms of integrin trafficking is pivotal for understanding tumor progression and for the development of anticancer drugs.
Influence of Inuloprebiotic Supplementation of the Diets of Broiler Chickens on Shelf-Life and Quality Characteristics of Meat
Park Sang-Oh,Park Byung-Sung
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2011.1336.1341
Abstract: In the present study, as an alternative to antibiotics in broiler diets, microencapsulated-inuloprebiotics extracted from Korean Jerusalem artichoke was manufactured as a natural antimicrobial agents and added to broiler diets after which the quality and storability of chicken meat were investigated. A total of 360, 1 day old Ross 308 broiler chicks were randomly assigned to 3 treatment groups that were each replicated 4 times. The broilers were then divided into T1 (control), T2 (Avilamycin 8 g ton-1) and T3 (inuloprebiotics 250 g ton-1). The pH, water holding capacity and water content of chicken meat was significantly higher in T3 than T1 and T2. Additionally, the L* value (lightness) and b* value (yellowness) of the meat was significantly higher in T3 than T1 and T2. The TBARS value during low temperature storage of chicken thighs was significantly lower in T3 than T1 and T2. Finally, the sensory evaluation scores of the cooked chicken meat were significantly higher in T3 than T1 and T2. The results of this study suggest that the addition of inuloprebiotics as an alternative for antibiotics to broiler diets can greatly improve the quality and the storability of chicken meat.
Effects of Grain Larvae Extracts on Hepatotoxicity and Blood Lipid in Obese Rats
Park Byung-Sung,Park Sang-Oh
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2012.988.994
Abstract: The purpose of this study was to evaluate the effect of the ethanol extract from the grain larvae (GLE: Grain Larvae Ethanol extract) on the blood lipid level of high-fat diet-induced obese rats (Experiment I) and on the protective effect of liver damage in rats that were given intraperitoneal injections of Chlorotetracycline (CCl4) and alcohol (Experiment II). For Experiment I, 27 male rats (SDS strain) were randomized into three treatment groups: NC (Normal Control group fed with chow diet without the administration of GLE), HO (High-fat diet induced Obese group) and HOE (High-fat diet induced Obese rats administered orally with GLE 5.0 mg/100 g body weight). For Experiment II, 45 male rats (SDS strain) were randomized into five treatment groups: T1 (control group), T2 (intraperitoneal injection of CCl4), T3 (oral administration of GLE combined with intraperitoneal injection of CCl4), T4 (combined administration of GLE and alcohol) and T5 (intraperitoneal injection of alcohol combined with oral administration of GLE). Compared with HO, the levels of triglyceride, total cholesterol and LDL-cholesterol in blood decreased significantly in HOE while the HDL-cholesterol level showed a significant increase (p<0.05). Concentrations of AST, ALT, γ-GTP and bilirubin in blood significantly decreased in T3 and T5 groups with oral administration of GLE, compared with T2 and T4 groups (p<0.05). In rats in T3 and T5 groups, recovery of liver tissue cells from damage that had been induced by intraperitoneal injections of CCl4 (T2) and alcohol (T4) could be observed.
Effect of Dietary Microencapsulated-Inulin on Carcass Characteristics and Growth Performance in Broiler Chickens
Park Sang-Oh,Park Byung-Sung
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2011.1342.1349
Abstract: In the present study, we investigated the effect of Microencapsulated-Inulin (MCI) in feed on the improvement of the growth performance in broilers using MCI prepared from Korean Jerusalem artichoke as a natural antibacterial growth promoter. After sex identification, 320 male Ross 308 broilers were randomly allotted to treatment groups and fed for 35 days. Treatment groups consisted of T1 (no supplementation; control), T2 (avilamycin, 8 g ton-1), T3 (MCI, 200 g ton-1) and T4 (MCI, 250 g ton-1). The growth performance and the dressing percentage were higher in broilers in groups T3 and T4 than in broilers in groups T1 and T2; statistical significance in the differences among the treatment groups was verified. The weights of breast and thigh muscles were significantly higher in broilers in T3 and T4 than in T1 and T2 and abdominal fat was significantly lower in broilers in T3 and T4 than in T1 and T2 with a decrease of 19.08-23.30%. The levels of blood immunoglobulins, IgG, IgM, IgA and weights of thymus and bursa of fabricius were significantly greater in T3 and T4 compared with T1 and T2 with an increase of IgG, IgM and IgA being 125.1-168.5, 100.5-170.5 and 103.0-125.3%, respectively. The colony counts of the beneficial intestinal microorganisms, Bifidobacteria and Lactobacillus were significantly greater in T3 and T4 than in T1 and T2 but the counts of harmful E. coli and Salmonella were significantly less in T3 and T4 than in T1 and T2. The supplementation of broiler feed with 200 g ton-1 microencapsulated-inulin can significantly improve the productivity of broiler chickens.
Usefulness of Cellular Analysis of Bronchoalveolar Lavage Fluid for Predicting the Etiology of Pneumonia in Critically Ill Patients
Sang-Ho Choi, Sang-Bum Hong, Hyo-Lim Hong, Sung-Han Kim, Jin Won Huh, Heungsup Sung, Sang-Oh Lee, Mi-Na Kim, Jin-Yong Jeong, Chae-Man Lim, Yang Soo Kim, Jun Hee Woo, Younsuck Koh
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0097346
Abstract: Background The usefulness of bronchoalveolar lavage (BAL) fluid cellular analysis in pneumonia has not been adequately evaluated. This study investigated the ability of cellular analysis of BAL fluid to differentially diagnose bacterial pneumonia from viral pneumonia in adult patients who are admitted to intensive care unit. Methods BAL fluid cellular analysis was evaluated in 47 adult patients who underwent bronchoscopic BAL following less than 24 hours of antimicrobial agent exposure. The abilities of BAL fluid total white blood cell (WBC) counts and differential cell counts to differentiate between bacterial and viral pneumonia were evaluated using receiver operating characteristic (ROC) curve analysis. Results Bacterial pneumonia (n = 24) and viral pneumonia (n = 23) were frequently associated with neutrophilic pleocytosis in BAL fluid. BAL fluid median total WBC count (2,815/μL vs. 300/μL, P<0.001) and percentage of neutrophils (80.5% vs. 54.0%, P = 0.02) were significantly higher in the bacterial pneumonia group than in the viral pneumonia group. In ROC curve analysis, BAL fluid total WBC count showed the best discrimination, with an area under the curve of 0.855 (95% CI, 0.750–0.960). BAL fluid total WBC count ≥510/μL had a sensitivity of 83.3%, specificity of 78.3%, positive likelihood ratio (PLR) of 3.83, and negative likelihood ratio (NLR) of 0.21. When analyzed in combination with serum procalcitonin or C-reactive protein, sensitivity was 95.8%, specificity was 95.7%, PLR was 8.63, and NLR was 0.07. BAL fluid total WBC count ≥510/μL was an independent predictor of bacterial pneumonia with an adjusted odds ratio of 13.5 in multiple logistic regression analysis. Conclusions Cellular analysis of BAL fluid can aid early differential diagnosis of bacterial pneumonia from viral pneumonia in critically ill patients.
Viral Infection Is Not Uncommon in Adult Patients with Severe Hospital-Acquired Pneumonia
Hyo-Lim Hong, Sang-Bum Hong, Gwang-Beom Ko, Jin Won Huh, Heungsup Sung, Kyung-Hyun Do, Sung-Han Kim, Sang-Oh Lee, Mi-Na Kim, Jin-Yong Jeong, Chae-Man Lim, Yang Soo Kim, Jun Hee Woo, Younsuck Koh, Sang-Ho Choi
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095865
Abstract: Background Viral pathogens have not generally been regarded as important causes of severe hospital-acquired pneumonia (HAP), except in patients with hematologic malignancy or transplant recipients. We investigated the role and distribution of viruses in adult with severe HAP who required intensive care. Methods From March 2010 to February 2012, adult patients with severe HAP required admission to the intensive care unit (ICU), 28-bed medical ICU in a tertiary care hospital, were prospectively enrolled. Respiratory viruses were detected using multiplex reverse-transcription polymerase chain reaction and/or shell vial culture. Results A total of 262 patients were enrolled and 107 patients (40.8%) underwent bronchoscopic BAL for etiologic diagnosis. One hundred and fifty-six patients (59.5%) had bacterial infections and 59 patients (22.5%) had viral infections. Viruses were detected in BAL fluid specimens of 37 patients (62.7%, 37/59). The most commonly identified viruses were respiratory syncytial virus and parainfluenza virus (both 27.1%, 16/59), followed by rhinovirus (25.4%, 15/59), and influenza virus (16.9%, 10/59). Twenty-one patients (8.0%, 21/262) had bacterial-viral coinfections and Staphylococcus aureus was the most commonly coexisting bacteria (n = 10). Viral infection in non-immunocompromised patients was not uncommon (11.1%, 16/143), although it was not as frequent as that in immunocompromised patients (36.4%, 43/119). Non-immunocompromised patients were significantly older than immunocompromised patients and had significantly higher rates of underlying chronic obstructive pulmonary disease, tuberculous destroyed lung and chronic kidney disease. The 28 day mortalities of patients with bacterial infections, viral infections and bacterial-viral coinfections were not significantly different (29.5%, 35.6% and 19.0%, respectively; p = 0.321). Conclusions Viral pathogens are not uncommon in adult patients with severe HAP who required ICU admission. Since viral pathogens may cause severe HAP and could be a potential source of viral transmission, further investigation is required to delineate the role of viral pathogens in severe HAP.
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