First Case of Fungal Corneal Ulcer Caused by Pestalotiopsis mangiferae

Pestalotiopsis species are filamentous fungi that are known plant pathogens commonly isolated in tropical and subtropical regions. To the best of our knowledge, this is the first case of human infection caused by Pestalotiopsis mangiferae. An 80-year-old male farmer presented with ocular pain in the right eye. At initial presentation, slit-lamp examination showed a 3.0×2.5 mm-sized epithelial defect in the cornea of the right eye accompanied by corneal thinning. A KOH examination revealed spores, and consequently, treatment with voriconazole, ceftazidime, and moxifloxacin was initiated. One month later, a second KOH examination and fungal culture were performed. The results of the KOH examination indicated the presence of many hyphae, and fungus was isolated from the culture. Molecular identification revealed that the sequence had 100% similarity to P. mangiferae. The patient was treated with therapeutic penetrating keratoplasty. During follow-up in the outpatient clinic, signs of infection were not observed.

Isolation and Genetic Characterization of Orientia tsutsugamushi from Scrub Typhus Patients in Gyeongsangnam-do, Korea

Orientia tsutsugamushi (O. tsutsugamushi), which is endemic to an Asia-Pacific region, has increased its incidence and caused annually around 10 thousand patients infected with scrub typhus in Korea in the past several years. In the present study, we isolated 44 O. tsutsugamushi from the patients with febrile illness accompanied with or without an eschar in Gyeongsangnam-do, Korea. These isolates were characterized by genetic analysis of the major outer membrane protein, the 56-kDa type-specific antigen (tsa56), which is unique to O. tsutsugamushi. Two types of sequences of tsa56, designated by JJ1 and JJ2, were determined from 37 and 7 isolates of the 44 isolates, respectively. JJ1 and JJ2 showed 74.7~90.8% identity in nucleotide sequence and 66.1~90.5% identity in amino acid sequence with 33 reference strains except for Boryong and Kuroki. JJ1 and JJ2 had 100 and 99.9% nucleotide identity to Boryong strain, and 99.9 and 99.8% to Kuroki, which has been known to be similar to Boryong, respectively. In addition, they showed 77.9~ 81.4% nucleotide identity with the cluster of Gilliam-related genotypes, whereas they showed higher nucleotide identity (89.6~90.8%) with the cluster of Karp-related genotypes. To our knowledge, this is the first report to isolate O. tsutsugamushi and characterize their genotype as the Boryong in Jinju and West Gyeongsangnam-do, Korea, even though it has been reported that the Boryong was the predominant genotype in isolates from chiggers, domestic rodents, and patients in the southern part of Korea. Furthermore, our isolates could be useful source to study on the pathophysiology and epidemiology of scrub typhus in Korea.

Assessment of collagen antibody-induced arthritis in BALB/c mice using bioimaging analysis and histopathological examination / 한국실험동물학회지

The aim of this study was to examine the therapeutic potential of sulfasalazine and prednisolone in a mouse collagen antibody-induced arthritis (CAIA) model. Twenty-five male BALB/c mice were randomly divided into five groups: group 1 (G1): control, group 2 (G2): probe control, group 3 (G3): CAIA, group 4 (G4): CAIA+sulfasalazine (10 mg/kg, oral), and group 5 (G5): CAIA+prednisolone (100 mg/kg, oral). Fluorescence bioimaging was performed in vivo 24 and 48 h after treatment with a fluorescence probe (OsteoSense® 680 EX), and all mice were sacrificed. The hind knee joints were fixed in 10% neutral phosphate-buffered formalin, and micro-computed tomography (micro-CT) and histopathological analyses were performed. The paw thickness increased in a time-dependent manner in G3 mice, but trended toward a decrease in both G4 and G5 mice. Fluorescence intensity increased in G3 mice at 24 and 48 h after fluorescence probe treatment, but the fluorescence intensity in G4 and G5 mice was lower than that in G3. Micro-CT analyses showed that the joint surfaces of G3 mice had a rough and irregular articular appearance, but the occurrence of these irregularities was lower in G4 and G5. Hematoxylin and eosin and Safranin O-fast green staining confirmed that destruction of the cartilage and bony structures, synovial hyperplasia, and inflammatory cell infiltration all occurred in G3, and that the occurrence of these phenomena was lower in G4 and G5 than in G3. Taken together, these results suggest that sulfasalazine and prednisolone can reduce acute rheumatoid arthritis in mice.

Two Cases of Bacteremia Due to Roseomonas mucosa

Roseomonas is a genus of pink-pigmented nonfermentative bacilli. These slow-growing, gram-negative cocobacilli form pink-colored colonies on sheep blood agar. They differ from other pink-pigmented nonfermenters, including Methylobacterium, in morphology, biochemical characteristics, and DNA sequence. Roseomonas strains are rarely isolated in clinical laboratories; therefore, we report two cases in order to improve our ability to identify these pathogens. We isolated two strains of Roseomonas mucosa from the venous blood cultures of two patients, an 84-yr-old woman with common bile duct obstruction and a 17-yr-old male with acute myeloid leukemia who had an indwelling central-venous catheter for chemotherapy. The isolated strains were confirmed as R. mucosa by 16S rRNA sequencing.

A Case of Trichosporon asahii Fungemia with Urinary Tract Infection as a Primary Focus / 대한임상미생물학회지

Since the report of disseminated trichosporonosis in 1970s, several cases of infection by various Trichosporon species in different clinical patients were published. We've isolated a strain of T. asahii from not only blood but also urine. We report 71 year-old male patient with Trichosporon asahii fungemia, who had renal stones. It was identified as T. asahii using conventional method and also confirmed by 18S rRNA gene sequencing. The patient was discharged without any complication, in which case only antibiotic agent was used without any antifungal one.

A Case of Alternaria alternata Keratitis Isolated from Corneal Tissue / 대한의진균학회지

A 71-year-old man presented with pain in the left eye that revealed a 3x3 mm deep corneal stromal infiltrate, with a 2x2 mm epithelial defect. The patient started topical moxifloxacin, voriconazole 2%, and natamycin for 2 weeks. However, the treatment was not effective and the corneal infiltration worsened. Subsequently, the patient underwent therapeutic penetrating keratoplasty. Thick brown/gray mold colonies on Potato Corn Meal Tween 80 agar was isolated from excised corneal tissue and on slide culture many septated, and club-shaped ascospores were revealed. Histological findings also showed numerous hyphae scattered in corneal tissue. A. alternata colonies were confirmed by 18S rRNA sequencing. Intracameral voriconazole was injected every other day for 2 weeks to eliminate remaining fungi on the deep corneal stroma. The remaining corneal infiltration was improved one month after the injection. During 5 months postoperative follow up, the infection did not recurred. In conclusion, deep corneal infection of A. alternata was effectively treated with intracameral voriconazole injection.

Association between Apolipoprotein E Genotype and Treatment Response in Chronic Hepatitis C / 대한임상미생물학회지

BACKGROUND: Hepatitis C virus (HCV) causes a chronic infection, resulting in progressive liver damage. Recent studies have described the protective effect of the apolipoprotein E (ApoE) genotype on liver damage in cases of HCV infection. Their findings were explained by the influence of the ApoE genotype on HCV pathology, which seems to be integrally linked to the process of HCV uptake into hepatocytes. We investigated whether specific ApoE genotypes were associated with the different clinical aspects of HCV infection in patients with chronic HCV. METHODS: From the whole blood of 196 chronic HCV hepatitis patients, the ApoE genotypes were determined by an allele-specific polymerase chain reaction. Several markers, including liver enzymes, platelet counts and HCV viral loads, as well as the radiologic findings, were investigated. In order to estimate the treatment outcome, the sustained virologic response (SVR), early virologic response (EVR) and end-of-treatment response (ETR) were determined according to the HCV viral loads. RESULTS: Based on genotyping, 15.8% (n=31) of the patients had the ApoE E4 allele (E2/E4, E3/E4, E4/E4), while 84.2% (n=165) were missing the ApoE E4 allele (E2/E2, E2/E3, E3/E3). Several clinical results of the E4-positive group, including liver enzymes, albumin, platelet counts, HCV viral loads and hepatic coarseness were not significantly different from those of E4-negative group. There were no differences in the SVR, EVR and ETR between patients with the ApoE E4 allele and those without the ApoE E4 allele. CONCLUSION: There was no significant effect of the ApoE genotype on the clinical aspects of HCV infection and the anti-viral response, including SVR, EVR and ETR, in chronic HCV hepatitis patients.

Distribution of Yeast and Mold Species Isolated from Clinical Specimens at 12 Hospitals in Korea during 2011 / 대한임상미생물학회지

BACKGROUND: The incidence of fungal infections varies among hospitals and between different time periods. We performed a nationwide survey in Korea to investigate the distribution of yeast and mold species recovered from clinical specimens. METHODS: The distributions of clinical isolates of yeast and mold species obtained from 12 university hospitals between January and December 2011 were evaluated relative to the hospital and specimen type. RESULTS: A total of 39,533 fungal isolates (37,847 yeast and 1,686 mold isolates) were obtained. C. albicans was the predominant species (49.4%) among the yeast isolates from all clinical specimens, followed by C. glabrata (7.2%) and C. tropicalis (6.5%). For 5,248 yeast isolates from sterile body fluids, blood was the most common source of yeasts (71.1%), followed by peritoneal fluid (9.4%). Although C. albicans was the predominant species at all but two hospitals, the rate of non-albicans Candida species varied from 71.2% to 40.1%, depending on the hospital. The yeast species recovered most frequently from the sterile body fluids was C. albicans (41.7%), followed by C. parapsilosis (17.8%) and C. glabrata (14.4%), while that from non-sterile sites was C. albicans (50.7%), followed by C. glabrata (6.0%) and C. tropicalis (5.5%). For mold-forming fungi, Aspergillus species (62.3%) were most common, followed by Trichophyton species (15.4%). Respiratory specimens were the most common source of molds (39.6%), followed by abscesses/wounds (28.4%) and tissues (17.5%). CONCLUSION: The rank order of distribution for different fungal species varied among hospitals and specimen types. Continual national surveillance programs are essential for identifying possible changes in fungal infection patterns.

Evaluation of an Automated Urine Flow Cytometer for Screening of Bacterial Contamination in Platelet Concentrates

BACKGROUND: Bacterial contamination of blood products, particularly of platelet concentrates (PCs), is a major risk factor for infections caused by blood transfusion. Various methods for the detection of bacterial contamination in PCs are available or are under investigation. We evaluated the usefulness of the Sysmex UF-1000i urine flow cytometer (Sysmex Medical Electronics Co, Japan) for screening of bacterial contamination in PCs. METHODS: The PCs were inoculated with various concentrations of bacteria (Staphylococcus aureus and Escherichia coli) and were analyzed with the urine flow cytometer for bacterial counts. All the samples were diluted with normal saline (1:10) before flow cytometric analysis in order to prevent interference by the turbidity due to platelets. RESULTS: For PCs inoculated with a high number (colony forming unit, CFU) of bacteria (105 CFU/mL), the bacterial counts were significantly higher than those for uninoculated PCs analyzed by the urine flow cytometer. However, bacterial counts for PCs inoculated with bacteria of 104 CFU/mL or less and those for uninoculated PCs were not significantly different. CONCLUSIONS: An automated urine flow cytometer evaluated in this study is easy to use, and the procedure is completed in less than 5 min. Moreover, the urine flow cytometer could detect approximately 105 CFU/mL of bacteria in PCs. Further validation studies are needed to assess the usefulness of this method for screening of bacterial contamination in PCs.

An Unusual Feature of Malaria: Exflagellated Microgametes of Malarial Parasites in Human Peripheral Blood / 대한임상미생물학회지

Exflagellation of the malaria parasite microgametocyte usually occurs in the gut cavity of Anopheles mosquitoes following an infective blood meal. Exflagellation is a very rare event in human blood. Due to its rarity, the appearance of this structure in a peripheral blood smear will easily create a diagnostic dilemma. We report a case of malaria with exflagellated microgametes in human blood that was initially mistaken for a double infection of Plasmodium and another blood flagellate. The patient was a 29-year-old Parkistani man presenting with fluctuating fever accompanied by chills and fatigue for 4 days. Initial peripheral blood smear examination showed a number of Plasmodium ring forms, trophozoites, and gametocytes. Additionally, several filamentous structures resembling blood flagellates were seen. With these features, an initial diagnostic impression of combined infection of malaria and blood flagellate was made. Later, we determined that these structures resembling blood flagellates were exflagellated microgametes of malarial parasite. Therefore, the knowledge that exflagellation may appear in human blood with Plasmodium species infection and being more familiar with differentiation of the morphologic features of other species infection can prevent further possible misinterpretation.

Novel Influenza A (H1N1) Infection in Immunocompromised Patients / 대한진단검사의학회지

BACKGROUND: Since April 2009, novel influenza A (H1N1) infection is spreading throughout the world. This infection might be fatal for immunocompromised patients who are at a potentially high risk of developing infectious complications. We investigated the detection rate and features of H1N1 infection in immunocompromised patients. METHODS: Between August 2009 and February 2010, we examined 8,112 subjects, including 390 immunocompromised patients, for H1N1. Swab samples were taken from the nose and throat of the participants. Real-time PCR was performed to identify H1N1 viral genes. RESULTS: Positive results were obtained in 2,953/8,112 (36.4%) subjects and 46/390 (11.8%) immunocompromised patients. H1N1 was identified in 8.7% patients with solid cancer, 12.9% patients with hematologic malignancy, 16.7% patients with chronic renal disease, and 14.5% patients with kidney transplantation. The mean cycle threshold (Ct) value of PCR was significantly lower (P<0.05) in patients with hematologic malignancy as compared to that in patients with chronic renal disease and control subjects. Four patients died due to respiratory complications. CONCLUSIONS: The detection rate of H1N1 was significantly lower in immunocompromised patients than in other patients. The Ct value of patients with hematologic malignancy was significantly lower than that of other immunocompromised patients and control subjects.

Comparison of Collagen-coated Polyethylene Terephthalate Disc Plate and Shell Vial Culture Method for the Isolation of Chlamydophila pneumoniae / 대한임상미생물학회지

BACKGROUND: Chlamydophila pneumoniae is one of the major respiratory infectious pathogens and can be accurately diagnosed by cell culturing. The author performed this study to compare the usefulness of the collagen-coated polyethylene terephthalate (PET) disc culture method and that of the shell vial method. METHODS: Twenty-nine sputums and 17 blood specimens collected from 46 patients for C. pneumoniae culture were inoculated into HeLa-229 cell monolayers cultured in shell vials and polyester plates. After incubation, they were stained using the indirect immunofluorescent method with genus-specific FITC-conjugated anti-chlamydia antibody. When both results were inconsistent, microimmunofluorescence results were used. RESULTS: HeLa-229 cells successfully formed monolayers in shell vials and collagen-coated PET plates in all cases. Positive inclusion bodies in HeLa-229 cells of shell vials and PET plates for C. pneumoniae culture were similarly stained with the indirect immunofluorescent method. Both methods showed consistent results with 20 positive and 22 negative cases. The total agreement between the PET plate and shell vial was excellent (91.3%, k=0.826). CONCLUSION: The collagen-coated PET disc culture method showed highly consistent results with that of the shell vial method, and no technical differences were experienced between the two methods. Therefore, the author concluded that the shell vial method could be replaced by the PET plate method for detection of C. pneumoniae.

Reducing Patient Waiting Time for the Outpatient Phlebotomy Service Using Six Sigma / 대한진단검사의학회지

BACKGROUND: One of the challenging issues of the outpatient phlebotomy services at most hospitals is that patients have a long wait. The outpatient phlebotomy team of Kyungpook National University Hospital applied six sigma breakthrough methodologies to reduce the patient waiting time. METHODS: The DMAIC (Define, Measure, Analyze, Improve, and Control) model was employed to approach the project. Two hundred patients visiting the outpatient phlebotomy section were asked to answer the questionnaires at inception of the study to ascertain root causes. After correction, we surveyed 285 patients for same questionnaires again to follow-up the effects. RESULTS: A defect was defined as extending patient waiting time so long and at the beginning of the project, the performance level was 2.61 sigma. Using fishbone diagram, all the possible reasons for extending patient waiting time were captured, and among them, 16 causes were proven to be statistically significant. Improvement plans including a new receptionist, automatic specimen transport system, and adding one phlebotomist were put into practice. As a result, the number of patients waited more than 5 min significantly decreased, and the performance level reached 3.0 sigma in December 2007 and finally 3.35 sigma in July 2008. CONCLUSIONS: Applying the six sigma, the performance level of waiting times for blood drawing exceeding five minutes were improved from 2.61 sigma to 3.35 sigma.

Ectopic expression of cyclooxygenase-2-induced dedifferentiation in articular chondrocytes

Cyclooxygenase-2 (COX-2) is known to modulate bone metabolism, including bone formation and resorption. Because cartilage serves as a template for endochondral bone formation and because cartilage development is initiated by the differentiation of mesenchymal cells into chondrocytes (Ahrens et al., 1977; Sandell and Adler, 1999; Solursh, 1989), it is of interest to know whether COX-2 expression affect chondrocyte differentiation. Therefore, we investigated the effects of COX-2 protein on differentiation in rabbit articular chondrocyte and chick limb bud mesenchymal cells. Overexpression of COX-2 protein was induced by the COX-2 cDNA transfection. Ectopic expression of COX-2 was sufficient to causes dedifferentiation in articular chondrocytes as determined by the expression of type II collagen via Alcian blue staining and Western blot. Also, COX-2 overexpression caused suppression of SOX-9 expression, a major transcription factor that regulates type II collagen expression, as indicated by the Western blot and RT-PCR. We further examined ectopic expression of COX-2 in chondrifying mesenchymal cells. As expected, COX-2 cDNA transfection blocked cartilage nodule formation as determined by Alcian blue staining. Our results collectively suggest that COX-2 overexpression causes dedifferentiation in articular chondrocytes and inhibits chondrogenic differentiation of mesenchymal cells.

RNAi: A Recent Revolutionary Tool for Understanding of Basic Biology / 대한임상미생물학회지

RNA interference (RNAi) is a gene-silencing technology by which small double-stranded RNAs are used to target the degradation of RNA with complementary sequence. RNAi is found in a wide variety of organisms (Caenorhabditis elegans, insects, plants, microorganisms and animals). With RNAi, we have harnessed the gene function to be explored, revolutionized our ability to perform large-scale genetic screens, and even therapeutic potential.

ERK-1/-2 and p38 Kinase Oppositely Regulate 15-deoxy-delta(12,14)-prostaglandinJ2-Induced PPAR-gamma Activation That Mediates Dedifferentiation But Not Cyclooxygenase-2 Expression in Articular Chondrocytes

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a ligand-activated transcription factor and plays an important role in growth, differentiation, and inflammation in different tissues. In this study, we investigated the effects of 15d-PGJ2, a high-affinity ligand of PPAR-gamma, on dedifferentiation and on inflammatory responses such as COX-2 expression and PGE2 production in rabbit articular chondrocytes with a focus on ERK-1/-2, p38 kinase, and PPAR-gamma activation. We report here that 15d-PGJ2 induced dedifferentiation and/or COX-2 expression and subsequent PGE2 production. 15d-PGJ2 treatment stimulated activation of ERK-1/-2, p38 kinase, and PPAR-gamma. Inhibition of ERK-1/-2 with PD98059 recovered 15d-PGJ2-induced dedifferentiation and enhanced PPAR-gamma activation, whereas inhibition of p38 kinase with SB203580 potentiated dedifferentiation and partially blocked PPAR-gamma activation. Inhibition of ERK-1/-2 and p38 kinase abolished 15d-PGJ2-induced COX-2 expression and subsequent PGE2 production. Our findings collectively suggest that ERK-1/-2 and p38 kinase oppositely regulate 15d-PGJ2-induced dedifferentiation through a PPAR-gamma-dependent mechanism, whereas COX-2 expression and PGE2 production is regulated by ERK-1/-2 through a PPAR-gamma-independent mechanism but not p38 kinase in articular chondrocytes. Additionally, these data suggest that targeted modulation of the PPAR-gamma and mitogen-activated protein kinase pathway may offer a novel approach for therapeutic inhibition of joint tissue degradation.

15-Deoxy-delta 12,14-ProstaglandinJ2 Regulates Dedifferentiation through Peroxisome Proliferator-Activated Receptor-gamma-Dependent Pathway but Not COX-2 Expression in Articular Chondrocytes

Peroxisome proliferator-activated receptors-gamma (PPAR-gamma) is critical for phenotype determination at early differentiation stages of mesenchymal cells, whereas its physiological role is unclear. Therefore, we investigated the role of 15-deoxy-delta 12,14-prostaglandinJ2 (15d-PGJ2), the natural receptor ligand for PPAR-gamma, on dedifferentiation and inflammatory responses, such as COX-2 expression and PGE2 production, in articular chondrocytes. Our data indicate that the 15d-PGJ2 caused a loss of differentiated chondrocyte phenotype as demonstrated by inhibition of type II collagen and proteoglycan synthesis. 15d-PGJ2 also induced COX-2 expression and PGE2 production. The 15d-PGJ2-induced dedifferentiation effect seems to be dependent on PPAR-gamma activation, as the PPRE luciferase activity increased and PPAR-gamma antagonist, BADGE, abolished type II collagen expression. However, BADGE did not block 15d-PGJ2-induced COX-2 expression. Collectively, our findings suggest that PPAR-gamma-dependent and -independent mechanisms of 15d-PGJ2-induced dedifferentiation and inflammatory responses in articular chondrocytes, respectively. Additionally, these data suggest that targeted modulation of the PPAR-gamma pathway may offer a novel approach for therapeutic inhibition of joint tissue degradation.

TT Virus (TTV) Infection in General Population, Chronic Liver Diseases, Hemodialysis, and Transfused Patients / 대한임상미생물학회지

BACKGROUND: TT virus (TTV), isolated initially from a Japanese patient with posttransfusion hepatitis of unknown etiology, was suggested to be a new causative agent of hepatitis. However, it has been found to infect both healthy and diseased individuals and numerous studies have raised questions about its pathogenic role in hepatitis. In order to study its prevalence and clinical impact on hepatitis, we assessed the frequency of TTV DNA. METHODS: Serum samples were obtained from 60 cases of the controls, 77 cases of chronic liver diseases, 44 cases of hemodialyzed patients, and 65 cases of transfused patients. TTV DNA was detected using nested polymerase chain reaction and alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatitis B surface antigen (HBsAg) were measured. RESULTS: TTV DNA was detected in 41.7% of the controls, 51.9% of patients with chronic liver diseases, 68.2% of hemodialyzed patients and 61.5% of transfused patients. Comparison between patients with or without TTV revealed no significant differences in AST, ALT, and HBsAg test results. CONCLUSION: The prevalance of TTV infection in patients with chronic liver diseases was similar to that in the controls. TTV infection was not related to abnormal liver function findings and HBsAg positivity. We found no relationship between TTV infection and chronic liver diseases.

Src Kinase Regulates Nitric Oxide-induced Dedifferentiation and Cyclooxygenase-2 Expression in Articular Chondrocytes via p38 Kinase-dependent Pathway

BACKGROUND: Nitric oxide (NO) in articular chondrocytes regulates dedifferentiation and inflammatory responses by modulating MAP kinases. In this study, we investigated whether the Src kinase in chondrocytes regulates NO-induced dedifferentiation and cyclooxygenase-2 (COX-2) expression. METHODS: Primary chondrocytes were treated with various concentrations of SNP for 24 h. The COX-2 and type II collagen expression levels were determined by immunoblot analysis, and prostaglandin E(2) (PGE(2)) was determined by using a PGE(2) assay kit. Expression and distribution of p-Caveolin and COX-2 in rabbit articular chondrocytes and cartilage explants were determined by immunohistochemical staining and immunocytochemical staining, respectively. RESULTS: SNP treatment stimulated Src kinase activation in a dose-dependent manner in articular chondrocytes. The Src kinase inhibitors PP2 [4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine], a significantly blocked SNP-induced p38 kinase and caveolin-1 activation in a dose-dependent manner. Therefore, to determine whether Src kinase activation is associated with dedifferentiation and/or COX-2 expression and PGE(2) production. As expected, PP2 potentiated SNP-stimulated dedifferentiation, but completely blocked both COX-2 expression and PGE2 production. And also, levels of p-Caveolin and COX-2 protein expression were increased in SNP-treated primary chondrocytes and osteoarthritic and rheumatoid arthritic cartilage, suggesting that p-Caveolin may play a role in the inflammatory responses of arthritic cartilage. CONCLUSION: Our previously studies indicated that NO caused dedifferentiation and COX-2 expression is regulated by p38 kinase through caveolin-1 (1). Therefore, our results collectively suggest that Src kinase regulates NO-induced dedifferentiation and COX-2 expression in chondrocytes via p38 kinase in association with caveolin-1.

In Vitro Antimicrobial Activities of Silver Nanoparticles (NANOVER) against Clinical Isolates / 대한임상미생물학회지

BACKGROUND: Silver has extensive and powerful antimicrobial activities and silver-containing materials have been widely used in many medical fields. Recently nanoparticulate silver was developed and it is superior to other types of silver in the antimicrobial activity and cytotoxicity. There have been no data from Korea on its antimicrobial activity, and we evaluated the antimicrobial activity of NANOVER against common clinical isolates. METHODS: Minimum inhibitory concentrations (MICs) of NANOVER for clinical isolates were determined using the agar dilution method of Clinical and Laboratory Standard Institute. A total of 45 isolates were tested including 4 reference strains (Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC 29212), 5 strains of methicillin-resistant S.aureus (MRSA), 7 strains of methicillin-sensitive S. aureus (MSSA), 14 strains of E.coli,and 15 strains of P. aeruginosa. RESULTS: The MICs of S.aureus to NANOVER were under 12.5 microgram/mL regardless of the methicillin sensitivity or resistance. The other isolates showed the MICs under 12.5 to 6.25 microgram/mL. CONCLUSION: NANOVER has strong and extensive antimicrobial activities to common clinical isolates including those resistant to other antimicrobials.