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1.  Visual working memory deficits in patients with Parkinson's disease are due to both reduced storage capacity and impaired ability to filter out irrelevant information 
Brain  2010;133(9):2677-2689.
Given that Parkinson's disease broadly affects frontostriatal circuitry, it is not surprising that the disorder is associated with a reduction of working memory. We tested whether this reduction is due to diminished storage capacity or impaired ability to exclude task-irrelevant items. Twenty-one medication-withdrawn patients and 28 age-matched control subjects performed a visuospatial memory task while their electroencephalograms were recorded. The task required them to remember the orientations of red rectangles within the half of the screen that was cued while ignoring all green rectangles. Behavioural and electroencephalogram measures indicated that patients with Parkinson's disease were impaired at filtering out distracters, and that they were able to hold fewer items in memory than control subjects. The results support recent suggestions that the basal ganglia help control access to working memory.
PMCID: PMC2929336  PMID: 20688815
Parkinson's disease; visual working memory; event-related potentials; selective attention; dopamine
2.  Comparison of Patients Starting Hemodialysis with Those Underwent Hemodialysis 15 Years Ago at the Same Dialysis Center in Korea 
Maintenance dialysis is made decreased the death rate of patients with end-stage renal disease; however, mortality is still high. The aim of this study was to identify the association between clinical parameters at the start of hemodialysis with survival and compare these findings with data from patients who underwent hemodialysis about 15 years ago at the same dialysis center.
We reviewed 117 patients who started hemodialysis between 2000 and 2004. We analyzed medical histories, laboratory findings, and clinical outcomes, and compared them with patients who started hemodialysis 15 years ago at the same center.
The proportion of elderly patients and those with diabetes increased from 17% and 18% in the previous study to 33% and 49% in this study, respectively. Elderly and patients with diabetes had much higher mortalities than their counterparts. Nevertheless, the overall survival rate (66% vs. 71% at 5 years) and survival of patients with diabetes improved (55% vs. 75% at 1.5 years). Common causes of death were infection and cardiovascular disease in the present study; however, inadequate dialysis accounted for 25% of deaths in the previous study.
The overall survival rate of patients undergoing hemodialysis has improved over the 15-year interval, even with an increased proportion of elderly patients and patients with diabetes. Adequate dialysis and further medical improvements could ameliorate mortality in patients undergoing dialysis.
PMCID: PMC2880693  PMID: 20526393
Renal dialysis; Mortality; Survival analysis
3.  The Korean urban rural elderly cohort study: study design and protocol 
BMC Geriatrics  2014;14:33.
Korea is one of the fastest aging countries and is expected to become a super-aged society within 12 years. The Korean Urban Rural Elderly (KURE) study was developed to evaluate the epidemiological characteristics and establish the prevention and management of major disorders of the elderly in Korea.
The KURE study is a community-based prospective cohort study on health, aging, and common geriatric disorders of Korean elderly persons aged at least 65 years. To construct a cohort reflecting both urban and rural areas, we selected 2 representative communities in the country. To establish multidisciplinary approaches to geriatric health, this study was performed by researchers in the divisions of geriatrics, preventive medicine, endocrinology, and sociology. The baseline examinations began in 2012; the study will follow more than 4,000 elderly Koreans over 10 years. The first and second follow-up health examinations will be performed every 4 years. Every 2 years after each health examination, inter-assessment interview will be conducted to improve participant retention.
The KURE study will provide longitudinal epidemiologic data on health, aging, and common geriatric disorders of the elderly in Korea. This is a comprehensive, multidisciplinary study of the elderly with respect to biological, physical, socio-economic, and environmental factors. The results of this study will contribute to improve public health and welfare policies for the aging society in Korea.
PMCID: PMC3995180  PMID: 24641351
Aging; Elderly; Cohort; Longitudinal study; Health
4.  Urokinase, urokinase receptor, and plasminogen activator inhibitor-1 expression on podocytes in immunoglobulin A glomerulonephritis 
The purpose of this study was to investigate the expression of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), and plasminogen activator inhibitor (PAI)-1 on podocytes in immunoglobulin A (IgA) glomerulonephritis (GN).
Renal biopsy specimens from 52 IgA GN patients were deparaffinized and subjected to immunohistochemical staining for uPA, PAI-1, and uPAR. The biopsies were classified into three groups according to the expression of uPA and uPAR on podocytes: uPA, uPAR, and a negative group. The prevalences of the variables of the Oxford classification for IgA GN were compared among the groups.
On podocytes, uPA was positive in 11 cases and uPAR was positive in 38 cases; by contrast, PAI-1 was negative in all cases. Expression of both uPA and uPAR on podocytes was less frequently accompanied by tubulointerstitial fibrosis.
Our results suggest a possible protective effect of podocyte uPA/uPAR expression against interstitial fibrosis.
PMCID: PMC3956987  PMID: 24648800
Glomerulonephritis, IGA; Plasminogen activator inhibitor 1; Urokinase-type plasminogen activator; Receptors, urokinase plasminogen activator
5.  Taurine Alleviates the Progression of Diabetic Nephropathy in Type 2 Diabetic Rat Model 
The overexpression of vascular endothelial growth factor (VEGF) is known to be involved in the pathogenesis of diabetic nephropathy. In this study, the protective effects of taurine on diabetic nephropathy along with its underlying mechanism were investigated. Experimental animals were divided into three groups: LETO rats as normal group (n = 10), OLETF rats as diabetic control group (n = 10), and OLETF rats treated with taurine group (n = 10). We treated taurine (200 mg/kg/day) for 20 weeks and treated high glucose (HG, 30 mM) with or without taurine (30 mM) in mouse cultured podocyte. After taurine treatment, blood glucose level was decreased and insulin secretion was increased. Taurine significantly reduced albuminuria and ACR. Also it decreased glomerular volume, GBM thickness and increased open slit pore density through decreased VEGF and increased nephrin mRNA expressions in renal cortex. The antioxidant effects of taurine were confirmed by the reduction of urine MDA in taurine treated diabetic group. Also reactive oxygen species (ROS) levels were decreased in HG condition with taurine treated podocytes compared to without taurine. These results indicate that taurine lowers glucose level via increased insulin secretion and ameliorates the progression of diabetic nephropathy through antifibrotic and antioxidant effects in type 2 diabetes rat model.
PMCID: PMC3953422  PMID: 24707287
6.  The Effect of Dialysis Membrane Flux on Amino Acid Loss in Hemodialysis Patients 
Journal of Korean Medical Science  2007;22(4):598-603.
We examined whether high flux membranes (HF) may induce a greater loss of amino acids compared to low flux membranes (LF). Ten hemodialysis patients participated in this study. Pre- and post-hemodialysis plasma amino acid profiles were measured by reverse-phase high pressure liquid chromatography for both HF and LF. We measured the dialysate amino acid losses during hemodialysis. The reduction difference for plasma total amino acid (TAA), essential amino acid (EAA), and branch chained amino acid (BCAA) was not significantly different in comparisons between the two membranes. (HF vs. LF; TAA 66.85±30.56 vs. 53.78±41.28, p=0.12; EAA 14.79±17.16 vs. 17.97±28.69, p=0.12; BCAA 2.21±6.08 vs. 4.16±10.98 mg/L, p=0.13). For the HF, the reduction in plasma amino acid levels for TAA and EAA were statistically significant. Although it was not statistically significant, the dialysate losses of BCAA were greater than the reduction in plasma (plasma reduction vs. dialysate loss; HF 2.21±6.08 vs. 6.58±4.32, LF 4.16±10.98 vs. 7.96±3.25 mg/L). HF with large pores and a sieving coefficient do not influence dialysate amino acid losses. Hemodialysis itself may influence the dialysate amino acid losses and may have an effect on protein metabolism.
PMCID: PMC2693805  PMID: 17728495
Amino Acid; High Flux Membrane; Low Flux Membrane
7.  Pharmacokinetics of Glutathione and Its Metabolites in Normal Subjects 
Journal of Korean Medical Science  2005;20(5):721-726.
To determine the loading and maintenance dosage of glutathione (GSH) for patients suffering from reactive oxygen species (ROS) injury such as acute paraquat intoxication, a kinetic study of reduced GSH was performed in synchrony with that of cysteine (Cys), cystine (Cys2), and methionine (Met). Human subject's porticipitation was voluntary. The effective dose of Cys, Cys2, and Met against ROS in fibroblast cells generated by paraquat was assessed using laser scanning confocal microscopy. Both Cys and Met suppressed ROS in a dose-dependent manner at concentrations of 1-1,000 µM; the concentration required to suppress ROS by 50% was 10 µM for Cys and 50 µM for Met. Using metabolite kinetics with the assumption that Cys and Met are the metabolites of GSH, expected concentrations of Cys and Met of above 20 and 50 µM were estimated when GSH was administered at 50 mg/kg body weights every 205.4 min for Cys and 427.4 min for Met.
PMCID: PMC2779265  PMID: 16224142
Cysteine; Cystine; Glutathione; Methionine; Paraquat; Reactive Oxygen Species; Pharmacokinetics
8.  Negative Regulation of Osteoclast Precursor Differentiation by CD11b and β2 Integrin-BCL6 Signaling 
Negative regulation of osteoclastogenesis is important for bone homeostasis and prevention of excessive bone resorption in inflammatory and other diseases. Mechanisms that directly suppress osteoclastogenesis are not well understood. In this study we investigated regulation of osteoclast differentiation by the β2 integrin CD11b/CD18 that is expressed on myeloid lineage osteoclast precursors. CD11b-deficient mice exhibited decreased bone mass that was associated with increased osteoclast numbers and decreased bone formation. Accordingly, CD11b and β2 integrin signaling suppressed osteoclast differentiation by preventing RANKL-induced induction of the master regulator of osteoclastogenesis NFATc1 and of downstream osteoclast-related NFATc1 target genes. CD11b suppressed induction of NFATc1 by the complementary mechanisms of downregulation of RANK expression and induction of recruitment of the transcriptional repressor BCL6 to the NFATC1 gene. These findings identify CD11b as a negative regulator of the earliest stages of osteoclast differentiation, and provide an inducible mechanism by which environmental cues suppress osteoclastogenesis by activating a transcriptional repressor that makes genes refractory to osteoclastogenic signaling.
PMCID: PMC3522783  PMID: 22893614
osteoclast; signaling; integrin; CD11b; BCL6
9.  Comparison of Two Creatinine-Based Equations for Predicting Decline in Renal Function in Type 2 Diabetic Patients with Nephropathy in a Korean Population 
Aim. To compare two creatinine-based estimated glomerular filtration rate (eGFR) equations, the chronic kidney disease epidemiology collaboration (CKD-EPI) and the modification of diet in renal disease (MDRD), for predicting the risk of CKD progression in type 2 diabetic patients with nephropathy. Methods. A total of 707 type 2 diabetic patients with 24 hr urinary albumin excretion of more than 30 mg/day were retrospectively recruited and traced until doubling of baseline serum creatinine (SCr) levels was noted. Results. During the follow-up period (median, 2.4 years), the CKD-EPI equation reclassified 10.9% of all MDRD-estimated subjects: 9.1% to an earlier stage of CKD and 1.8% to a later stage of CKD. Overall, the prevalence of CKD (eGFR < 60 mL/min/1.73 m2) was lowered from 54% to 51.6% by applying the CKD-EPI equation. On Cox-regression analysis, both equations exhibited significant associations with an increased risk for doubling of SCr. However, only the CKD-EPI equation maintained a significant hazard ratio for doubling of SCr in earlier-stage CKD (eGFR ≥ 45 mL/min/1.73 m2), when compared to stage 1 CKD (eGFR ≥ 90 mL/min/1.73 m2). Conclusion. In regard to CKD progression, these results suggest that the CKD-EPI equation might more accurately stratify earlier-stage CKD among type 2 diabetic patients with nephropathy than the MDRD study equation.
PMCID: PMC3884626  PMID: 24454370
10.  Staphylococcus aureus Extracellular Vesicles Carry Biologically Active β-Lactamase 
Gram-positive bacteria naturally produce extracellular vesicles. However, little is known regarding the functions of Gram-positive bacterial extracellular vesicles, especially in the bacterial community. Here, we investigated the role of Staphylococcus aureus extracellular vesicles in interbacterial communication to cope with antibiotic stress. We found that S. aureus liberated BlaZ, a β-lactamase protein, via extracellular vesicles. These extracellular vesicles enabled other ampicillin-susceptible Gram-negative and Gram-positive bacteria to survive in the presence of ampicillin. However, S. aureus extracellular vesicles did not mediate the survival of tetracycline-, chloramphenicol-, or kanamycin-susceptible bacteria. Moreover, S. aureus extracellular vesicles did not contain the blaZ gene. In addition, the heat-treated S. aureus extracellular vesicles did not mediate the survival of ampicillin-susceptible bacteria. The β-lactamase activities of S. aureus soluble and extracellular vesicle-associated BlaZ were similar, but only the extracellular vesicle-associated BlaZ was resistant to protease digestion, which suggests that the enzymatic activity of BlaZ in extracellular vesicles is largely protected by the vesicle structure. Our observations provide evidence of the important role of S. aureus extracellular vesicles in antibiotic resistance, which allows the polymicrobial community to continue to evolve and prosper against antibiotics.
PMCID: PMC3716153  PMID: 23529736
11.  Mice Deficient in Interferon-Gamma or Interferon-Gamma Receptor 1 Have Distinct Inflammatory Responses to Acute Viral Encephalomyelitis 
PLoS ONE  2013;8(10):e76412.
Interferon (IFN)-gamma is an important component of the immune response to viral infections that can have a role both in controlling virus replication and inducing inflammatory damage. To determine the role of IFN-gamma in fatal alphavirus encephalitis, we have compared the responses of wild type C57BL/6 (WTB6) mice with mice deficient in either IFN-gamma (GKO) or the alpha-chain of the IFN-gamma receptor (GRKO) after intranasal infection with a neuroadapted strain of sindbis virus. Mortalities of GKO and GRKO mice were similar to WTB6 mice. Both GKO and GRKO mice had delayed virus clearance from the brain and spinal cord, more infiltrating perforin+ cells and lower levels of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 mRNAs than WTB6 mice. However, inflammation was more intense in GRKO mice than WTB6 or GKO mice with more infiltrating CD3+ T cells, greater expression of major histocompatibility complex-II and higher levels of interleukin-17A mRNA. Fibroblasts from GRKO embryos did not develop an antiviral response after treatment with IFN-gamma, but showed increases in TNF-alpha, IL-6, CXCL9 and CXCL10 mRNAs although these increases developed more slowly and were less intense than those of WTB6 fibroblasts. These data indicate that both GKO and GRKO mice fail to develop an IFN-gamma-mediated antiviral response, but differ in regulation of the inflammatory response to infection. Therefore, GKO and GRKO cannot be considered equivalent when assessing the role of IFN-gamma in CNS viral infections.
PMCID: PMC3811984  PMID: 24204622
12.  PSMB9 Codon 60 Polymorphisms Have No Impact on the Activity of the Immunoproteasome Catalytic Subunit B1i Expressed in Multiple Types of Solid Cancer 
PLoS ONE  2013;8(9):e73732.
The proteasome is a key regulator of cellular protein homeostasis and is a clinically validated anticancer target. The immunoproteasome, a subtype of proteasome expressed mainly in hematopoietic cells, was initially recognized for its role in antigen presentation during the immune response. Recently, the immunoproteasome has been implicated in several disease conditions including cancer and autoimmune disorders, but many of the factors contributing to these pathological processes remain unknown. In particular, the codon 60 polymorphism of the PSMB9 gene encoding the β1i immunoproteasome catalytic subunit has been investigated in the context of a variety of diseases. Despite this, previous studies have so far reported inconsistent findings regarding the impact of this polymorphism on proteasome activity. Thus, we set out to investigate the impact of the PSMB9 codon 60 polymorphism on the expression and activity of the β1i immunoproteasome subunit in a panel of human cancer cell lines. The β1i-selective fluorogenic substrate Acetyl-Pro-Ala-Leu-7-amino-4-methylcoumarin was used to specifically measure β1i catalytic activity. Our results indicate that the codon 60 Arg/His polymorphism does not significantly alter the expression and activity of β1i among the cell lines tested. Additionally, we also examined the expression of β1i in clinical samples from colon and pancreatic cancer patients. Our immunohistochemical analyses showed that ∼70% of clinical colon cancer samples and ∼53% of pancreatic cancer samples have detectable β1i expression. Taken together, our results indicate that the β1i subunit of the immunoproteasome is frequently expressed in colon and pancreatic cancers but that the codon 60 genetic variants of β1i display similar catalytic activities and are unlikely to contribute to the significant inter-cell-line and inter-individual variabilities in the immunoproteasome activity.
PMCID: PMC3767749  PMID: 24040045
13.  Tofacitinib Prevents Radiographic Progression in Rheumatoid Arthritis 
Journal of Korean Medical Science  2013;28(8):1134-1138.
Tofacitinib, a novel Janus kinase inhibitor, may prevent structural damage in rheumatoid arthritis (RA). In this cohort study, we compared radiographic progression of hand joints between 21 RA patients who took tofacitinb for 18 months in a phase IIb and its extension study and 42 patients who took conventional disease modifying antirheumatic drugs (DMARDs), using simple erosion narrowing score. For tofacitinib group, changes before and after the treatment were also compared. The changes of erosion and sum scores were significantly less in tofacitinib than DMARDs group (for erosion, -0.60 ± 1.83 vs 0.51 ± 1.77, P = 0.038; for sum, -0.50 ± 1.72 vs 1.57 ± 4.13, P = 0.012). Joint space narrowing score (JSN) was also less in tofacitinib group (0.095 ± 0.58 vs 1.06 ± 2.60, P = 0.055). In tofacitinib group, yearly rates of both erosion and JSN were significantly decreased after administration of tofacitinib (For erosion, 0.62 ± 0.93 to -0.14 ± 0.48, P = 0.009; for JSN, 0.47 ± 0.64 to 0.03 ± 0.40, P = 0.032), as was change of sum score (1.09 ± 1.27 to -0.10 ± 0.63, P < 0.001). In conclusion, tofacitinib may prevent structural damage caused by RA.
PMCID: PMC3744699  PMID: 23960438
Arthritis, Rheumatoid; Radiographic Progression; Tofacitinib
14.  Incidence, Etiology, and Outcomes of Rhabdomyolysis in a Single Tertiary Referral Center 
Journal of Korean Medical Science  2013;28(8):1194-1199.
We have encountered numerous cases of rhabdomyolysis associated with acute pesticide intoxication; however, the cause, incidence, and treatment outcomes of rhabdomyolysis have not been studied. The current study involved 2,125 patients hospitalized with acute chemical poisoning. Based on clinical and laboratory parameters and treatment outcomes, we found that overall incidence of rhabdomyolysis in our hospital was 0.06% (93 of 143,830 patients admitted), but the incidence associated with acute pesticide intoxication was 1.8% (33 of 1,793 cases). The incidence of rhabdomyolysis after pesticide intoxication was significantly higher in men than in women (P = 0.010). The amount of pesticide ingested was significantly higher in rhabdomyolysis patients than that in those who did not develop rhabdomyolysis (mean ± SD, 114.1 ± 79.5 mL vs 74.1 ± 94.2 mL, P = 0.010). Our results show that pesticide intoxication is a frequent cause of rhabdomyolysis and is more common among men than women. The volume of pesticide ingested, and not the degree of human toxicity, is the main factor influencing the incidence of rhabdomyolysis.
PMCID: PMC3744708  PMID: 23960447
Acute Kidney Injury; Intoxication; Pesticides; Rhabdomyolysis; Surfactant
15.  Clinical characteristics and treatment responses of patients who developed tuberculosis following use of a tumor necrosis factor-α inhibitor 
Individuals being treated with tumor necrosis factor (TNF)-α inhibitors are at increased risk of developing tuberculosis (TB). We determined the clinical characteristics and treatment response of patients who developed TB after using TNF-α inhibitors.
Patients with TB detected within 12 months of the initiation of TNF-α inhibitor treatment were included, if seen from January 1, 2000 to August 31, 2011. We retrospectively reviewed the clinical records, results of bacteriological examinations, and radiographs of the included patients and the response to anti-TB treatment.
We indentified seven cases of TB in 457 patients treated with TNF-α inhibitors during the study period. TB developed a median of 123 days (range, 48 to 331) after the first dose of TNF-α inhibitor. Pulmonary TB, including TB pleuritis, was diagnosed in three patients and extrapulmonary TB in four. Favorable treatment outcomes were achieved in six of seven patients.
Among the TNF-α inhibitor users who contracted TB, extrapulmonary sites were common and the treatment response was satisfactory.
PMCID: PMC3604607  PMID: 23525649
Tumor necrosis factor-alpha; Tuberculosis; Mycobacterium
16.  Analysis of 18F-fluorodeoxyglucose positron emission tomography findings in patients with pituitary lesions 
Although magnetic resonance imaging (MRI) is a good visual modality for the evaluation of pituitary lesions, it has limited value in the diagnosis of mixed nodules and some cystic lesions. We evaluated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG PET) for patients with pituitary lesions.
18F-FDG PET and MRI were performed simultaneously in 32 consecutive patients with pituitary lesions. The relationships between FDG uptake patterns in PET and MRI findings were analyzed.
Of 24 patients with piuitary adenomas, 19 (79.2%) showed increased uptake of 18F-FDG in the pituitary gland on PET scans. All patients with pituitary macroadenomas showed increased 18F-FDG uptake on PET scans. Meanwhile, only five (50%) of the 10 patients with pituitary microadenomas showed positive PET scans. Interestingly, of two patients with no abnormal MRI findings, one showed increased 18F-FDG uptake on PET. For positive 18F-FDG uptake, maximum standardized uptake values (SUVmax) > 2.4 had 94.7% sensitivity and 100% specificity. In addition, SUVmax increased in proportion to the size of pituitary adenomas. Most cystic lesions did not show 18F-FDG uptake on PET scans.
About 80% of pituitary adenomas showed positivity on PET scans, and SUVmax was related to the size of the adenomas. PET may be used as an ancillary tool for detection and differentiation of pituitary lesions.
PMCID: PMC3543965  PMID: 23346000
Pituitary; Positron-emission tomography; Magnetic resonance imaging
18.  Peroxisome proliferator-activated receptor δ agonist attenuates hepatic steatosis by anti-inflammatory mechanism 
Experimental & Molecular Medicine  2012;44(10):578-585.
Although peroxisome proliferator receptor (PPAR)-α and PPAR-γ agonist have been developed as chemical tools to uncover biological roles for the PPARs such as lipid and carbohydrate metabolism, PPAR-δ has not been fully investigated. In this study, we examined the effects of the PPAR-δ agonist GW0742 on fatty liver changes and inflammatory markers. We investigated the effects of PPAR-δ agonist GW0742 on fatty liver changes in OLETF rats. Intrahepatic triglyceride contents and expression of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and monocyte chemo-attractant protein-1 (MCP-1) and also, PPAR-γ coactivator (PGC)-1α gene were evaluated in liver tissues of OLETF rats and HepG2 cells after GW0742 treatment. The level of TNF-α and MCP-1 was also examined in supernatant of Raw264. 7 cell culture. To address the effects of GW0742 on insulin signaling, we performed in vitro study with AML12 mouse hepatocytes. Rats treated with GW0742 (10 mg/kg/day) from 26 to 36 weeks showed improvement in fatty infiltration of the liver. In liver tissues, mRNA expressions of TNF-α, MCP-1, and PGC-1α were significantly decreased in diabetic rats treated with GW0742 compared to diabetic control rats. We also observed that GW0742 had inhibitory effects on palmitic acid-induced fatty accumulation and inflammatory markers in HepG2 and Raw264.7 cells. The expression level of Akt and IRS-1 was significantly increased by treatment with GW0742. The PPAR-δ agonist may attenuate hepatic fat accumulation through anti-inflammatory mechanism, reducing hepatic PGC-1α gene expression, and improvement of insulin signaling.
PMCID: PMC3490079  PMID: 22824914
diabetes mellitus; fatty liver; GW0742; inflammation; monocyte chemo-attractant protein-1; PPAR δ; PPARGC1A protein, human; tumor necrosis factor-α
19.  Prediction of Microbial Infection of Cultured Cells Using DNA Microarray Gene-Expression Profiles of Host Responses 
Journal of Korean Medical Science  2012;27(10):1129-1136.
Infection by microorganisms may cause fatally erroneous interpretations in the biologic researches based on cell culture. The contamination by microorganism in the cell culture is quite frequent (5% to 35%). However, current approaches to identify the presence of contamination have many limitations such as high cost of time and labor, and difficulty in interpreting the result. In this paper, we propose a model to predict cell infection, using a microarray technique which gives an overview of the whole genome profile. By analysis of 62 microarray expression profiles under various experimental conditions altering cell type, source of infection and collection time, we discovered 5 marker genes, NM_005298, NM_016408, NM_014588, S76389, and NM_001853. In addition, we discovered two of these genes, S76389, and NM_001853, are involved in a Mycolplasma-specific infection process. We also suggest models to predict the source of infection, cell type or time after infection. We implemented a web based prediction tool in microarray data, named Prediction of Microbial Infection (
PMCID: PMC3468746  PMID: 23091307
Prediction Model; Microbial Infection; DNA Microarray; Mycoplasma
20.  Atorvastatin inhibits osteoclastogenesis by decreasing the expression of RANKL in the synoviocytes of rheumatoid arthritis 
Arthritis Research & Therapy  2012;14(4):R187.
Statins, hydroxymethylglutaryl-coenzyme A reductase inhibitors, have been reported to have antiinflammatory and/or immunomodulatory effects and prophylactic and therapeutic effects in collagen-induced arthritis, an experimental model of rheumatoid arthritis (RA). The authors undertook to determine the effect of atorvastatin on the expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) in RA fibroblast-like synoviocytes (FLSs), to identify the mechanisms responsible for these effects, and to determine whether the statin inhibits osteoclastogenesis.
FLSs isolated from five RA patients were cultured in the presence of 20 ng/ml of tumor necrosis factor-α (TNF-α) with or without atorvastatin. RANKL expressions were assayed with Western blotting and enzyme-linked immunosorbent assay. RANKL, RANK, and OPG expression were assayed with reverse transcription-polymerase chain reaction (RT-PCR). Osteoclast formation was assayed by counting cells after staining for tartrate-resistant acid phosphatase in cocultures of peripheral blood mononuclear cells (PBMCs) and RA FLSs.
Atorvastatin inhibited the expression of RANKL in RA FLSs in a dose-dependent manner, and the suppression of RANKL was prevented by mevalonate. However, OPG expression was not affected by atorvastatin in RA FLSs, and atorvastatin did not affect RANK expression in CD14+ cells. Conversely, atorvastatin suppressed TNF-α-induced p38 phosphorylation in RA FLSs and significantly reduced TRAP-positive multinucleated osteoclast formation in the coculture of PBMCs and RA FLSs.
These results suggest that atorvastatin inhibits osteoclastogenesis and bone destruction in RA patients.
PMCID: PMC3580583  PMID: 22901757
21.  Role of Plasma Exchange in ABO-incompatible Kidney Transplantation 
Annals of Laboratory Medicine  2012;32(4):283-288.
In the past, ABO incompatibility was an absolute contraindication for solid organ transplantation. However, multiple recent trials have suggested strategies for overcoming the reactions between graft antigens and recipient antibodies that cause graft rejection. In this study, we determined the usefulness of plasma exchange (PE) for removing anti-A/B antibodies that cause hyperacute/acute humoral graft rejection in patients undergoing ABO-incompatible kidney transplantation.
In our study, 12 patients underwent ABO-incompatible kidney transplantation. All recipients received pre-transplantation conditioning by PE or intravenous immunoglobulin (IVIG) administration. After pre-transplantation conditioning, anti-A/B antibody titers were evaluated, and transplantation was performed when the titer was below 1:8. To assess the transplantation outcome, anti-A/B antibody titers, creatinine level, estimated glomerular filtration rate (eGFR), and proteinuria levels were measured.
Anti-A/B antibody titers were below 1:8 in all patients at the time of transplantation. eGFR measured on post-transplant day 14 showed that 10 patients had immediate recovery of graft function, while 2 patients had slow recovery of graft function. Short-term outcomes of ABO-incompatible kidney transplantation (measured as creatinine levels) after reducing anti-A/B antibody titers were similar to those of ABO-compatible kidney transplantation. After transplantation, the anti-A/B antibody titers were below 1:8 in 7 patients, but the remaining 5 patients required post-transplantation PE and IVIG treatment to prevent antigen-antibody reactions.
With the increasing demand for kidney donations, interest in overcoming the ABO incompatibility barrier has increased. PE may be an important breakthrough in increasing the availability of kidneys for transplantation.
PMCID: PMC3384810  PMID: 22779070
Plasma exchange; ABO blood-group system; Blood group incompatibility; Kidney transplantation
22.  Serum Elastin-Derived Peptides and Anti-Elastin Antibody in Patients with Systemic Sclerosis 
Journal of Korean Medical Science  2012;27(5):484-488.
The elastin metabolism in systemic sclerosis (SSc) has been known to be abnormal. The authors investigated relationship between the clinical manifestations of systemic sclerosis (SSc) and serum levels of soluble elastin-derived peptide (S-EDP) and anti-elastin antibodies. Serum samples were obtained from 79 patients with SSc and 79 age- and sex-matched healthy controls. Concentrations of serum S-EDP and anti-elastin antibodies were measured by ELISA. The serum concentrations of S-EDP in SSc patients were significantly higher than in healthy controls (median, 144.44 ng/mL vs 79.59 ng/mL, P < 0.001). Serum EDP concentrations were found to be correlated with disease duration in SSc (P = 0.002) and particularly in diffuse cutaneous SSc (P = 0.005). Levels of anti-elastin antibodies were found to be more elevated in SSc patients than in healthy controls (median, 0.222 U vs 0.191 U, P = 0.049), more increased in diffuse cutaneous SSc than limited cutaneous SSc (median, 0.368 U vs 0.204 U, P = 0.031). In addition, levels of anti-elastin antibodies were also found to be negatively associated with presence of anti-centromere antibody (P = 0.023). The S-EDP levels were not found to be correlated with levels of anti-elastin antibodies. The increased S-EDP and anti-elastin antibody levels and association with clinical and laboratory characteristics may reflect the abnormal metabolism in SSc.
PMCID: PMC3342537  PMID: 22563211
Elastin; Elastin-Derived Peptide; Systemic Sclerosis
23.  Malignant Melanoma of Unknown Primary Origin Presenting as Cardiac Metastasis 
Korean Circulation Journal  2012;42(4):278-280.
Malignant melanoma has a very high propensity to metastasize to the heart. However, melanoma may sometimes present as a metastatic lesion in the absence of a primary lesion, which are called melanomas of unknown primary origin. We report a case in which a patient presented with a metastatic maligant melanoma in the right atrium with pericardial effusion and without a primary origin.
PMCID: PMC3341426  PMID: 22563342
Melanoma; Neoplasma, unknown primary; Unknown primary; Heart neoplasms
24.  Glucagon‐like peptide‐1 secretion by direct stimulation of L cells with luminal sugar vs non‐nutritive sweetener 
Aims/Introduction:  Oral ingestion of carbohydrate triggers secretion of glucagon‐like peptide (GLP)‐1, which inhibits the postprandial rise in blood glucose levels. However, the mechanism of carbohydrate‐induced GLP‐1 secretion from enteroendocrine L cells remains unclear. In the present study, GLP‐1 secretion was examined by meal tolerance tests of healthy Japanese volunteers.
Materials and Methods:  Twenty‐one healthy Japanese men participated in the study. The meal tolerance test was performed with modified nutrient compositions, with or without pretreatment with the α‐glucosidase inhibitor acarbose, or with substitution of sucrose with an equivalent dose of sweeteners in the meal. Blood concentrations of glucose, insulin, GLP‐1, and apolipoprotein (Apo) B‐48 were measured.
Results:  GLP‐1 secretion started concomitant with the increase in blood glucose levels 10 min after meal ingestion. Insulin secretion started at 5 min, before the increase in blood glucose levels, reflecting the contribution of direct nutrient stimulation on the former parameter and neural regulation in the latter. Carbohydrate retention in the gut lumen induced by acarbose pretreatment extended postprandial GLP‐1 secretion and negated the increase in serum ApoB‐48 levels. GLP‐1 secretion was markedly decreased by a reduction in the amount of sucrose in the meal and was not restored by an equivalent dose of sweeteners used to compensate for the sweet taste.
Conclusions:  The results indicate that direct stimulation of L cells with sugar, but not sweetener, is required for carbohydrate‐induced GLP‐1 secretion. In addition, inhibition of digestion of dietary carbohydrate by α‐glucosidase inhibitors may prevent postprandial hyperglycemia by increasing GLP‐1 secretion and by inhibiting glucose absorption. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00163.x, 2011)
PMCID: PMC4020733  PMID: 24843559
Acarbose; Apolipoprotein B‐48; Glucagon‐like peptide‐1
25.  Therapeutic Effects of Autologous Tumor-Derived Nanovesicles on Melanoma Growth and Metastasis 
PLoS ONE  2012;7(3):e33330.
Cancer vaccines with optimal tumor-associated antigens show promise for anti-tumor immunotherapy. Recently, nano-sized vesicles, such as exosomes derived from tumors, were suggested as potential antigen candidates, although the total yield of exosomes is not sufficient for clinical applications. In the present study, we developed a new vaccine strategy based on nano-sized vesicles derived from primary autologous tumors. Through homogenization and sonication of tumor tissues, we achieved high yields of vesicle-bound antigens. These nanovesicles were enriched with antigenic membrane targets but lacked nuclear autoantigens. Furthermore, these nanovesicles together with adjuvant activated dendritic cells in vitro, and induced effective anti-tumor immune responses in both primary and metastatic melanoma mouse models. Therefore, autologous tumor-derived nanovesicles may represent a novel source of antigens with high-level immunogenicity for use in acellular vaccines without compromising safety. Our strategy is cost-effective and can be applied to patient-specific cancer therapeutic vaccination.
PMCID: PMC3305328  PMID: 22438914

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