Search

The authors examined the needs of digital information service web portal users. More specifically, the needs of Korean cultural portal users were examined as a case study. The conceptual framework of a web-based portal is that it is a complex, web-based service application with characteristics of information systems and service agents. In addition, the users’ reactions to the technology can impact the service quality. As such, a model that specifically measured cultural portal user needs was created by implementing data quality, service quality and technology adoption models. Through confirmatory factor analyses and model respecifications, the authors suggest a measurement model consisting of 5 first-level latent variables, with 19 observed variables. The measurement model confirmed the research hypothesis that data quality, service quality, and technology adoption models complement each other in assessing the needs of cultural portal users. [ABSTRACT FROM PUBLISHER]

Pharyngeal pH monitoring is the standard diagnostic approach for laryngopharyngeal reflux (LPR). However, the normal values for Asian populations are still unknown. We evaluated the results of ambulatory 24-h pharyngeal pH monitoring in healthy volunteers to determine the normal reference values in the Korean population. Thirty healthy subjects underwent ambulatory 24-h pharyngeal pH monitoring with glass electrodes positioned 1 cm above the upper esophageal sphincter and 5 cm above the lower esophageal sphincter, based on esophageal manometry after upper gastrointestinal endoscopy. LPR occurred in about one half of the healthy volunteers without any significant association with age, gender and body mass index. Pharyngeal acid reflux occurred mainly in the upright position. At the 95th and 90th percentile, after the exclusion of mealtimes, the upper limits of normal (ULN) for pharyngeal acid exposure were 0.41% and 0.18%. The ULNs for the number of pharyngeal acid events were 12.8 and 5.0. The corresponding ULNs for the esophagus were 5.1% and 3.8% and 62.7 and 32.6. The findings of this study help establish the reference standards for LPR in Korean patients. [ABSTRACT FROM AUTHOR]

Objectives: To examine the molecular mechanisms involved in the beta-lactam resistance of multidrug-resistant Proteus mirabilis isolates that showed an unusual synergy between imipenem and ceftazidime in a Korean hospital.Methods: Over an 11 month period, a total of 12 P. mirabilis isolates showing resistance to ampicillin, gentamicin, ceftazidime, cefotaxime, cefuroxime, cefalothin, cefepime, piperacillin, trimethoprim/sulfamethoxazole and ciprofloxacin, were recovered from the sputum and urine specimens of nine patients who were hospitalized in the neurosurgery ward. The extended-spectrum beta-lactamases were screened with a double disc synergy test using ceftazidime, cefotaxime, aztreonam, cefepime and clavulanate. The ESBL types were determined by PCR using specific primers for bla(TEM-1), bla(SHV-1), bla(CTX-M-1), bla(CTX-M-2), bla(CTX-M-8), bla(CTX-M-9), bla(PER-1), bla(GES-1), bla(VEB-1), bla(OXA-10) and bla(OXA-13) followed by sequencing. All the isolates underwent molecular typing by PFGE. The transferability was examined by conjugation.Results and Conclusions: All the isolates showed a marked synergy between the extended-spectrum cephalosporins and clavulanate together with an unusual synergy between cefoxitin and the cephalosporins (cefalothin, cefuroxime, ceftazidime, cefotaxime) and between imipenem, and ceftazidime and cefotaxime. Isoelectric focusing of the crude bacterial extracts showed a beta-lactamase band with a pI value of 5.4, which was inhibited by clavulanate. PCR and sequencing identified the gene to be bla(VEB-1). In addition, the aadB gene was detected, conferring aminoglycoside resistance. The resistance was not transferred by conjugation. The outbreak was of a clonal origin as shown by PFGE demonstrating an identical banding pattern. This is the first report of VEB-1-producing Enterobacteriaceae in Korea. [ABSTRACT FROM AUTHOR]

The constituents and antimicrobial activity of the essential oil from Acorus calamus were analysed. Methyl isoeugenol and cyclohexanone were identified as the major constituents of the essential oil. The essential oil was tested for antimicrobial activity against bacteria and yeast, and has shown strong antibiotic activities against most of the tested microbes, except Escherichia coli. The hexane extract has shown a similar pattern of antimicrobial activity as the essential oil. Methyl isoeugenol, the most abundant constituent in the essential oil, has also shown similar antimicrobial activity, except against Bacillus subtilis. The essential oil as well as the hexane extract and methyl isoeugenol have shown antimicrobial activity against Propionibacterium acne, which is known to be involved in acne vulgaris.

Purpose: Bacteremia is a major infectious complication associated with mortality in liver transplant recipients. The causative organisms and clinical courses differ between medical centers due to variations in regional bacterial epidemiology and posttransplant care. Further, living donors in Korea contribute to 83% of liver transplants, and individualized data are required to improve survival rates., Patients and Methods: We retrospectively analyzed 104 subjects who had undergone living-donor liver transplant from 2005 to 2007., Results: Among the 144 consecutive living-donor liver transplant recipients, 24% (34/144) developed bacteremia, 32% (46/144) developed non-bacteremic infections, and 44% (64/144) did not develop any infectious complications. Forty episodes of bacteremia occurred in 34 recipients. The major sources of bacteremia were intravascular catheter (30%; 12/40), biliary tract (30%; 12/40), and abdomen (22.5%; 9/40). Gram-positive cocci were more common (57.5%; 23/40) than Gram-negative rods (32.5 %; 13/40) and fungi (10%; 4/40). The data revealed that the following factors were significantly different between the bacteremia, non-bacteremic infection, and no infection groups: age (p = 0.024), posttransplant hemodialysis (p = 0.002), ICU stay (p = 0.012), posttransplant hospitalization (p < 0.0001), and duration of catheterization (p < 0.0001). The risk factors for bacteremia were older than 55 years (odds ratio, 6.1; p = 0.003), catheterization for more than 22 days (odds ratio, 4.0; p = 0.009), UNOS class IIA (odds ratio, 6.6; p = 0.039), and posttransplant hemodialysis (odds ratio, 23.1; p = 0.001). One-year survival rates in the bacteremic, non-bacteremic infection, and no infection groups were 73.2%, 91.3%, and 93.5%, respectively., Conclusion: Early catheter removal and preservation of renal function should focus for improving survival after transplant.

Objectives: We investigated the occurrence and mechanism of amikacin resistance and its association with various beta-lactamase genes in Pseudomonas aeruginosa isolates., Methods: Of the total 250 consecutive, non-duplicated isolates of P. aeruginosa, 55 isolates showed amikacin resistance. PCR amplification of genes for aminoglycoside (AG)-modifying enzymes [aac(3)-I, aac(3)-II/VI, aac(3)-III/IV, aac(6')-I, aac(6')-II, ant(2'')-I, ant(4')-II and aph(3')-VI], 16S rRNA methylases (rmtA, rmtB, rmtC and armA) and class 1 integrons was performed. In addition, we analysed the association of AG resistance genes with various beta-lactamase genes., Results and Conclusions: In Korea, the amikacin resistance rate in P. aeruginosa was high (22%), and it varied among provinces (3.8% to 40%). Four types of AG-modifying enzyme genes [aph(3')-VI, ant(2'')-I, aac(6')-I and aac(3)-II/VI] were found in 48 isolates. Thirty-six strains harboured two or more types of enzymes, of which a combination of aph(3')-VI and ant(2'')-I was the most frequent (24/36 isolates, 66.7%). None harboured aac(3)-I, aac(3)-III/IV, aac(6')-II, ant(4')-II, rmtA, rmtB, rmtC or armA. Forty-two isolates co-harboured beta-lactamase genes (mostly bla(OXA-10)). A class 1 integron was detected in all but one, and all the ant(2'')-I and 26/29 bla(OXA-10) were found in it. In contrast, aph(3')-VI was not found to be associated with the class 1 integron. Considering the possibility of co-selection and dissemination, constant monitoring of resistance evolution is necessary.

Background and Objectives: The purpose of this study is to investigate characteristics of synchronous and metachronous cancer in gastric cancer and to suggest appropriate methods of treatment management., Methods: We reviewed 4,593 patients who underwent operations for gastric cancer at Seoul National University Hospital from 1999 to 2005. We selected those patients who had also been diagnosed with another primary cancer and classified patients into three groups according to the date of detection of another primary cancer. We analyzed their clinicopathological features., Results: The incidence of synchronous or metachronous cancer in addition to gastric cancer was 3.4%. The most common another primary cancer was colorectal cancer (20.1%), followed by lung cancer and liver cancer. The majority of synchronous cancers were operated on at the same time as gastric cancer. Eighty-five percent of the synchronous group and 45% of the post-metachronous group were detected by a routine checkup, without prior symptoms. There was no postoperative mortality and the overall 5-year survival rate was 69.4%., Conclusion: Synchronous cancer should be considered in the preoperative workup and combined resection should be applied whenever possible. Periodic examination for metachronous cancer is necessary during the postoperative period.

Background/aims: p53 gene plays an important role in cell cycle control in response to DNA damage which may increase the probability of mutations leading to carcinogenesis. The role of p53 gene polymorphisms [codon 72 (exon 4) and 16-bp duplication (intron 3)] as potential markers indicating cancer risk remains inconclusive, and the data on gastric cancer are very limited. The aim of this study was to assess the role of p53 gene polymorphisms in the risk of gastric cancer and in the determination of genetic susceptibility to gastric cancer in Koreans., Methods: We analysed p53 genotypes using a polymerase chain reaction-based restriction fragment length polymorphism assay in a population-based case-control study in 120 gastric cancer patients and 145 cancer-free controls in Koreans., Results: There was no specific genotype of p53 gene polymorphism in the gastric cancer patients compared to cancer-free controls. In p53 codon 72 and 16-bp duplication polymorphisms, the frequency and distribution of genotypes showed no statistical significance (p=0.7125 and p=0.1659). There was no difference in genotype by histologic subtypes, location of lesion, and age. However, the genotypic distribution in the patient subgroups with a history of heavy cigarette smoking of p53 16-bp duplication polymorphism were significantly different from those of cancer-free controls (p=0.0079)., Conclusions: The p53 codon 72 and 16-bp duplication polymorphisms were not associated with the increased risk of gastric cancer and did not seem to contribute to gastric cancer susceptibility among Koreans. It is possible that p53 16-bp duplication polymorphism modulates the risk of smoking-induced gastric cancer development in Koreans. In order to clarify the associations between specific genotypes and gastric cancer risk, the evaluations of these polymorphisms in other ethnic backgrounds with larger number of patients would be needed.

Background/aims: Diabetes is one of the risk factors of gallstone diseases. Many studies found a positive association between insulin and gallstones in individuals with diabetes. However, this association is unclear in non-diabetes. So we conducted a case-control study for the evaluation of the association between gallstone diseases and fasting serum insulin level, insulin resistance in non-diabetic Korean general population., Methods: This study was a prospective case-control study on 118 Korean subjects which included clinical examination, abdominal ultrasound, and blood chemistries. Serum fasting insulin level were determined by radioimmunoassay and concentrations of cholesterol, glucose, and triglycerides by standard enzymatic colorimetric methods. Insulin resistance was determined by the homeostasis model assessment (HOMA-IR). Body mass index (BMI), percentage of body fat, and waist hip ratio were also measured., Results: We studied 118 subjects with no clinical evidence of diabetes mellitus and serum glucose <126 mg/dL. Compared with controls (n=89), cases (n=29) had higher levels of serum insulin, glucose, triglyceride levels, and BMI. In t-test and chi-square test for variables, the association between gallstone disease and serum insulin, HOMA-IR index, and BMI were statistically significant (p<0.05). In multiple logistic regression analysis, gallstone disease risk increased with the level of serum insulin (p=0.024, odds ratio=1.376) and HOMA-IR index (p=0.013, odds ratio=2.006)., Conclusions: We suggest that hyperinsulinemia and insulin resistance could be associated with gallstone formation in individuals without clinical diagnosis of diabetes mellitus and with normal serum glucose level.

Extended-spectrum beta-lactamase-producing E. coli were recovered from 16 patients in a neurosurgical intensive care unit; surveillance cultures revealed that the organism could be transmitted through the contaminated environment and the hands of health care personnel. All isolates from the patients, environment, and health care personnel showed the same pulsed-field gel electrophoresis pattern. Isoelectric focusing, PCR analysis,and sequencing demonstrated that this E. coli harbored CTX-M-15 and OXA-30 beta-lactamases that were transferred by conjugation. This is the first report of nosocomial transmission caused by E. coli that harbor the combination of CTX-M-15 and OXA-30. This can be a threat because the organisms can hydrolyze cefotaxime, ceftazidime, and cefepime.

Primaquine is used for relapses caused by vivax malaria hypnozoites. No studies on the pharmacokinetics of primaquine (PMQ) has been reported in Korean patients. In our study, thirty vivax malaria patients were given 15 mg primaquine daily for 14 days after 3 days of chloroquine treatment. Plasma samples were taken at intervals after each daily dose of PMQ for 3 days. Plasma concentrations of PMQ and carboxyprimaquine (CPMQ), the major metabolite of primaquine, were measured by HPLC. The PMQ concentrations reached a maximum of 0.28+/-0.18 microg/mL at 1.5 h after the first dose. The maximum concentration of CPMQ was 0.32+/-0.13 microg/mL at 4 h. Higher drug concentrations with repeated dosing were observed for CPMQ, but not for the parent drug, PMQ. The elimination half-life was 3.76+/-1.8 h and 15.7+/-12.2 h, for PMQ and CPMQ, respectively. Large variation in the plasma concentrations of both drugs was observed. Overall, PMQ is absorbed and metabolized rapidly after oral administration. It was noted that the mean peak plasma concentration of PMQ was significantly higher and that of CPMQ was lower in our patients compared to other studies. This suggests a potential difference of inter-ethnic groups, which warrants further investigations.

To identify the metallo-beta-lactamases (MBLs) prevalent in Korea, a total of 130 clinical isolates of Pseudomonas aeruginosa and Acinetobacter baumannii (99 P. aeruginosa and 31 A. baumannii) with a reduced susceptibility to imipenem (IPM) and/or ceftazidime (CAZ) was subjected to PCR analyses with primers specific to bla(IMP-1), bla(VIM-1), and bla(VIM-2). In addition, inhibitor-potentiated disk diffusion methods (IPD) using two kinds of substrate-inhibitor combinations (ceftazidime-2-mercaptopropionic acid (2MPA) and imipenem-EDTA) were investigated. Thirty-three isolates (29 P. aeruginosa and 4 A. baumannii) carried bla(VIM-2) and two P. aeruginosa isolates harbored bla(IMP-1). The enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) pattern revealed that many of the VIM-2-producing P. aeruginosa isolates were clonally related, whereas the A. baumannii isolates were diverse. The inhibitor-potentiated disk diffusion test using imipenem-EDTA was highly sensitive and specific for detecting the VIM-2 producer. These results suggest that VIM-2 is an important MBL in P. aeruginosa and A. baumannii in the Korean hospital of this study and that the IMP-1-producing P. aeruginosa has also emerged. Screening for MBLs and strict infection control for these isolates will contribute to prevent further spread of resistance.

Gemifloxacin is an enhanced-affinity fluoroquinolone with broad-spectrum antibacterial activity. In Korea, resistant bacteria are relatively more prevalent than in other industrialized countries. In this study, we studied the in vitro activities of gemifloxacin, gatifloxacin, moxifloxacin, levofloxacin, ciprofloxacin, and other commonly used antimicrobial agents against 1,689 bacterial strains isolated at four Korean university hospitals during 1999-2000. Minimum inhibitory concentrations (MICs) were determined using the agar dilution method of National Committee for Clinical Laboratory Standards. Gemifloxacin had the lowest MICs for the respiratory pathogens: 90% of Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae were inhibited by 0.06, 0.03, and 0.03 mg/L, respectively. Gemifloxacin was more active than the other fluoroquinolones against methicillin-susceptible Staphylococcus aureus, coagulase-negative staphylococci, streptococci, and Enterococcus faecalis. The MIC90s of gemifloxacin for Klebsiella oxytoca, Proteus vulgaris, and non-typhoidal Salmonella spp. were 0.25, 1.0, and 0.12 mg/L, respectively, while those for other Gram-negative bacilli were 4-64 mg/L. In conclusion, gemifloxacin was the most active among the comparative agents against Gram-positive species, including respiratory pathogens isolated in Korea.

A nested PCR and direct sequencing methods were used to define human immunodeficiency virus type 1(HIV-1) reverse transcriptase codons 41 to 219 in DNA from 127 peripheral blood mononuclear cell samples obtained from 35 patients treated with nucleoside reverse transcriptase inhibitors (NRTI). The follow-up period after the initiation of NRTI therapy was 61.8 +/- 31 months (mean and standard deviation). In addition to NRTI therapy, 32 of 35 patients were simultaneously treated with Korean red ginseng. The annual decrease in the CD4(+) T-cell count over 5 years was 13.2/microl. Twenty-eight (80%) of the 35 patients had mutations conferring resistance to NRTI. The frequencies of K70R, T215S/Y/F (i.e., mutation of T at codon 215 to S, Y, or F), D67N/E, K219Q, T69N/S/A, M41L, and L210W mutations conferring resistance to zidovudine were 57.6, 36.4, 36.4, 27.2, 24.2, 21.2, and 12.1%, respectively. Mutations conferring resistance to didanosine and lamivudine were detected in 2 (L74V and M184I; 14.2%) of 11 patients tested and in 4 (M184V; 57%) of 7 patients tested, respectively. In particular, the frequency of T69N/S/A increased sharply after more than 48 months of zidovudine monotherapy. However, Q151M was not detected. As the first report on the frequency of NRTI resistance mutations in Korea, our data suggest that genotypic antiretroviral drug testing should be considered for the design of better drug regimens to improve the management of HIV-1-infected patients.