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Biomedical subjects

M S Lee

Publications and source records attributed to M S Lee.

At least 19 recordsLinked to original sources

Emerging invasive liver abscess caused by K1 serotype Klebsiella pneumoniae in Korea.

OBJECTIVES: The high incidence of invasive liver abscess caused by Klebsiella pneumoniae in Taiwan, contrasted with the rareness of this disease in Western countries, has aroused special interest. There have been few detailed reports from other Asian countries. To investigate a current epidemiology of K. pneumoniae liver abscess in Korea and to determine K serotype distribution in K. pneumoniae strains causing liver abscess, we performed a nationwide prospective study. METHODS: Community-acquired, culture-proven liver abscess cases were enrolled between 2004 and 2005. Etiologies and clinical features were analyzed. K. pneumoniae isolates were serotyped according to K antigen. Meta-analysis was done to determine the time trend of the etiologies of liver abscess in Korea. RESULTS: Out of 371 cases collected prospectively, 290 (78.2%) were caused by K. pneumoniae. Most K. pneumoniae liver abscesses were monomicrobial. Diabetes mellitus was the most common underlying disease (39.9%). Distant metastatic infections were frequently observed (8.7%). magA PCR revealed that 95 (59.4%) out of 160 K. pneumoniae isolates belonged to the K1 serotype. CONCLUSIONS: Our study indicates that K. pneumoniae has emerged as a major etiologic agent of liver abscess in Korea, and these emerging infections seem to be attributable to invasive K. pneumoniae strains with capsular K1 serotype.

Aged↗

Characterization of Lactobacillus plantarum PH04, a potential probiotic bacterium with cholesterol-lowering effects.

The bacterium Lactobacillus plantarum PH04 was isolated from infant feces and tested positive for bile/acid tolerance and bile salt hydrolase activity. It was evaluated as a potential probiotic with cholesterol-lowering effect. Bile salt hydrolase activity was nine times greater in stationary phase than in exponential phase cells and increased when the cells were exposed to conjugated bile salts. L. plantarum PH04 was resistant to seven of nine antibiotics tested and did not produce beta-glucuronidase. L. plantarum PH04 was fed to hypercholesterolemic mice at numbers of 10(7) CFU per mouse per day for 14 days. Compared with a control group, the serum cholesterol and triglycerides were respectively 7 and 10% lower in the group fed L. plantarum PH04, and fecal lactic acid bacteria increased while no any significant differences (P<0.05) in body weight, visceral weigh index or bacteria translocation between two groups were observed. The results indicated that L. plantarum PH04 might be effective as a probiotic with cholesterol-lowering activities.

Amidohydrolases↗

Linezolid-associated toxic optic neuropathy.

The oxazolidinone antimicrobial linezolid is effective against gram-positive bacteria. Although maximal recommended therapy is 28 days, treatment durations greater than this are common. Linezolid may cause reversible optic neuropathy and irreversible peripheral neuropathy after months of treatment. Three cases of linezolid-induced optic and peripheral neuropathy are described, and previously reported cases of linezolid-induced optic neuropathy are reviewed. The mechanism of neural toxicity may be impairment of mitochondrial protein synthesis.

Acetamides↗

A novel triple purge strategy for eliminating chronic myelogenous leukemia (CML) cells from autografts.

Imatinib-refractory chronic myelogenous leukemia (CML) patients can experience long-term disease-free survival with myeloablative therapy and allogeneic hematopoietic cell transplantation; however, associated complications carry a significant risk of mortality. Transplantation of autologous hematopoietic cells has a reduced risk of complications, but residual tumor cells in the autograft may contribute to relapse. Development of methods for purging tumor cells that do not compromise the engraftment potential of the normal hematopoietic cells in the autograft has been a long-standing goal. Since primitive CML cells differentiate more rapidly in vitro than their normal counterparts and are also preferentially killed by mafosfamide and imatinib, we examined the purging effectiveness on CD34(+) CML cells using a strategy that combines a brief exposure to imatinib (0.5-1.0 microM for 72 h) and then mafosfamide (30-90 microg/ml for 30 min) followed by 2 weeks in culture with cytokines (100 ng/ml each of stem cell factor, granulocyte colony-stimulating factor and thrombopoietin). Treatment with 1.0 microM imatinib, 60 microg/ml mafosfamide and 14 days of culture with cytokines eliminated BCR-ABL(+) cells from chronic phase CML patient aphereses, while preserving normal progenitors. This novel purging strategy may offer a new approach to improving the effectiveness of autologous transplantation in imatinib-refractory CML patients.

Antigens, CD↗

Diagnostic yield of advanced colorectal neoplasia at colonoscopy, according to indications: an investigation from the Korean Association for the Study of Intestinal Diseases (KASID).

BACKGROUND AND STUDY AIMS: The factors that more accurately predict the detection of colorectal cancers and adenomas at colonoscopy are different. We conducted a prospective multicenter study to evaluate which indications were most closely associated with advanced colorectal neoplasm (CRN), including colorectal cancer, in a group of patients undergoing colonoscopy. PATIENTS AND METHODS: The 17 468 patients were enrolled in this study between July 2003 and March 2004, from 11 tertiary medical centers in Korea. They were recruited according to 11 itemized colonoscopic indications. The term "advanced adenoma" refers here to tubular adenomas of diameter of 11 mm or more, or to tubulovillous, villous, or severely dysplastic adenomas, irrespective of their size. Cancer was defined as the invasion of malignant cells beyond the muscularis mucosa. Advanced CRN was defined as advanced adenoma or invasive cancer. RESULTS: Advanced CRN was found in 1227/17 307 patients (1176 advanced adenomas plus 51 carcinomas, 7.1 %). According to univariate and multivariate analysis, the factors associated with advanced CRN included age >60 years (odds ratio (OR) 2.1, 95 % confidence interval (CI) 1.8 - 2.4, P < 0.0001), male gender (OR 2.1, 95 %CI 1.7 - 2.7, P < 0.0001), referral for colonoscopy from primary care physician (OR 3.1, 95 %CI 2.5 - 3.7, P < 0.0001), and several other indications (OR 1.8, 95 %CI 1.5 - 2.3, P < 0.001). The yield of colonoscopy for advanced CRN was lower (2.2 %) than expected in patients with iron-deficiency anemia (OR 0.5, 95 %CI 0.2 - 0.9, P = 0.03). CONCLUSIONS: Age, gender, and referral for colonoscopy from primary care physician constituted important independent predictors of advanced CRN in patients undergoing colonoscopy.

Adenoma↗

Percutaneous coronary intervention in unprotected left main disease: a status report.

Percutaneous coronary intervention (PCI) of the unprotected left main (LM) artery is currently not recommended as a routine procedure based on the history of inferior outcomes of LM percutaneous transluminal coronary angioplasty and bare metal stenting. Instead, surgical revascularization (coronary artery bypass grafting, CABG) is considered to be the gold standard. There is renewed interest in LM-PCI because of improved outcomes of PCI utilizing drug eluting stents (DES) in multiple randomized trials. Several single-center non-randomized registries have evaluated the role of DES for LM-PCI. Data suggest a low mortality and target vessel failure of ostial LM or mid-shaft lesions in contrast to bifurcation lesions, which frequently require complex dual stenting techniques. The complex PCI in the bifurcation is associated with the increased occurrence of target vessel failure ranging from 2% and 38%. The rate of target vessel failure in bifurcation lesions is less in patients in whom the circumflex ostium is not involved so that single cross over stent is suitable. Current recommendations call for a follow-up angiography at 4-6 months to detect LM restenosis prior to a potentially fatal clinical event. The question of the duration of dual antiplatelet therapy in patients who underwent LM-PCI is unanswered. More registry data and randomized trials are needed before unprotected LM-PCI can be routinely offered to patients as an alternative to CABG.

Angioplasty, Balloon, Coronary↗

Corticospinal disinhibition in paroxysmal kinesigenic dyskinesia.

OBJECTIVE: To investigate the underlying mechanism responsible for paroxysmal kinesigenic dyskinesia (PKD). METHODS: We performed a transcranial magnetic stimulation (TMS) study in 12 drug-naïve patients with PKD and 10 healthy volunteers. TMS parameters included resting motor threshold, recruitment curve of motor evoked potential amplitudes, short intracortical inhibition and facilitation, long intracortical inhibition (LICI), and silent period. We also measured compound muscle action potential. RESULTS: LICI, representing GABA-mediated inhibition, was significantly reduced in the patients (P = 0.033), while results for all other TMS parameters tested were comparable between the two groups. CONCLUSIONS AND SIGNIFICANCE: These results suggest that a specific type of corticospinal inhibitory mechanism is impaired in patients with PKD.

Action Potentials↗

Inhibition of nitric oxide can ameliorate apoptosis and modulate matrix protein gene expression in bacteria infected chondrocytes in vitro.

Bacterial infection stimulates nitric oxide (NO) production in chondrocytes. However, the role of NO in chondrocyte apoptosis after infection remains unclear. The purpose of the study was to test if inhibition of NO could ameliorate apoptosis and modulate matrix protein gene expression in bacteria-infected chondrocytes. It was shown that pre-treating chondrocytes with L-NAME (1 mM) significantly decreased the release of NO (from 72 to 14 microM) and the extent of apoptosis (from 52.9% to 18.9%). Pre-treatment with L-NAME also counteracted the bacteria-induced downregulation of Type II collagen (from 26% to 79%) and aggrecan (from 63% to 105%) mRNA levels. Inhibition of NO after the induction of infection could not decrease the extent of apoptosis and modulate matrix protein gene expression. The results of this study support the hypothesis that NO has an important role in bacteria-induced chondrocyte apoptosis. Pre-treatment but not post-treatment could ameliorate the extent of apoptosis and reestablish the cartilage matrix protein gene expression. This study suggests that in addition to NO, other mechanisms may be responsible for the sustained destruction of articular cartilage in the post-infectious arthropathy.

Apoptosis↗

A more persistent tolerance to islet allografts through bone marrow transplantation in minimal nonmyeloablative conditioning therapy.

INTRODUCTION: Islet transplantation is a therapeutic approach to prevent diabetes complications. However, the side effects of the required lifelong immunosuppressive regimens to prevent graft rejection restrict the impact of type 1 diabetes. One strategy to overcome these limitations is tolerance induction and graft acceptance through hematopoietic chimerism. In this study we investigated whether tolerance to major histocompatibility complex (MHC) and minor-disparate islet allografts could be induced by minimal nonmyeloablative conditioning and whether more persistent donor-specific islet allografts were accepted if the grafts were implanted with simultaneous bone marrow cells. METHODS: The donor and recipient mice were BALB/c(H-2(b)) and C57BL/6(H-2(d)), respectively. In group 1 streptozotocin-induced diabetic C57BL/6(H-2(d)) mice received only 500 islets of BALB/c(H-2(b)). Group 2 recipients conditioned with antilymphocyte serum, 100 cGy total body irradiation and cyclophosphamide were given islet cells of BALB/c(H-2(b)), but group 3 were simultaneously given 30 x 10(6) BALB/c(H-2(b)) mice BMCs and islet cells similar to group 2. RESULTS: We obtained 5% to 6% allogeneic donor chimerism and 60% graft survival at 80 days after islet transplantation in group 3. We observed lymphocyte infiltration around the islet without destruction of endocrine cells and the presence of strong insulin/glucagon-stained cells in group 3. CONCLUSION: This minimal nonmyeloablative conditioning therapy induced donor chimerism and immune tolerance between MHC- and minor-disparate (BALB/c-->C57BL/6) mice and long-term islet graft survival was obtained through cotransplantation of bone marrow cells.

Animals↗

Management of malignant stricture of the esophagogastric junction with a newly designed self-expanding metal stent with an antireflux mechanism.

BACKGROUND AND STUDY AIMS: When stents are placed across the esophagogastric junction for palliative treatment of malignant strictures, they may lead to esophagogastric reflux. The aim of this study was to compare the effectiveness of a newly designed antireflux stent with that of a standard open stent and a currently available antireflux stent (Dostent) in preventing gastroesophageal reflux symptoms in patients with inoperable cancer at the esophagogastric junction. PATIENTS AND METHODS: Thirty-six consecutive patients with cancer at the esophagogastric junction were randomly assigned to undergo placement of a newly designed antireflux stent (n = 12), a Dostent (n = 12), or a standard open stent (n = 12). Technical and clinical success, dysphagia score, reflux symptoms, complications and ambulatory 24-h esophageal pH monitoring were assessed. RESULTS: The technical success rates were 100 %. After 1 week, dysphagia had improved in all patient groups ( P < 0.05), but the degree of improvement did not differ between the three groups. The DeMeester score was significantly lower in the group with the newly designed antireflux stent than in the other groups. The fraction of the total recording time during which esophageal pH was below 4 was 3.14 +/- 5.78 % using the newly designed antireflux stent, in comparison with 29.25 +/- 15.41 % in the Dostent group and 15.01 +/- 11.72 % in the standard open stent group ( P < 0.001). Fewer reflux episodes occurred with the newly designed antireflux stent than with the Dostent or standard open stent. There were no complications with any of the three stents. CONCLUSIONS: The newly designed antireflux stent is effective in relieving dysphagia caused by malignant cancer at the esophagogastric junction. The newly designed antireflux stent is significantly more effective in preventing gastroesophageal reflux than currently available antireflux stents.

Aged↗

Prospective study of the effectiveness of percutaneous transhepatic photodynamic therapy for advanced bile duct cancer and the role of intraductal ultrasonography in response assessment.

BACKGROUND AND STUDY AIMS: We evaluated the therapeutic effects of percutaneous transhepatic photodynamic therapy (PDT) in patients with advanced bile duct cancer. The utility of intraductal ultrasonography (IDUS) for the assessment of responses and for regular follow up after PDT was also examined. METHODS: Percutaneous transhepatic biliary drainage (PTBD) was initiated before PDT. Following dilation and maturation of the PTBD tract, percutaneous PDT was performed. Intraluminal photoactivation was carried out using percutaneous cholangioscopy 2 days after intravenous application of a hematoporphyrin derivative. All patients were additionally provided with percutaneous bile duct drainage catheters after PDT. IDUS was conducted monthly to measure the thickness of the tumor mass before and after PDT. RESULTS: 24 patients with advanced cholangiocarcinomas (Bismuth IIIa, n = 4; IIIb, n = 10; IV, n = 10) were treated with PDT. At 3 months after PDT, the mean thickness of the tumor mass had decreased from 8.7 +/- 3.7 mm to 5.8 +/- 2.0 mm (P < 0.01). At 4 months after PDT, the thickness of the mass had increased to 7.0 +/- 3.7 mm. Quality of life indices improved dramatically and remained stable 1 month after PDT; the Karnofsky index increased from 39.1 +/- 11.36 to 58.2 +/- 22.72 points (P = 0.003). The 30-day mortality rate was 0 %, and the median survival time was 558 +/- 178.8 days (current range 62 - 810 days). CONCLUSIONS: PDT using percutaneous cholangioscopy is safe and effective for advanced hilar cholangiocarcinoma, and seems to prolong survival. IDUS is useful for evaluating changes in the thickness of the tumor mass after PDT.

Adult↗

Effects of Qi therapy (external Qigong) on symptoms of advanced cancer: a single case study.

The aim of this study was to examine the effectiveness of Qi therapy (external Qigong) in the management of symptoms of advanced cancer in a man. We used a single case study design to evaluate the effectiveness of Qi therapy (external Qigong) in a 35-year-old man with advanced cancer (Stage IV) involving metastases in the stomach, lung and bone (Karnofsky performance scale: KPS, 40: requires special care and assistance, disabled). Treatment involved six days of pre-assessment, eight treatment sessions on alternate days over 16 days, and a two-week follow-up phase. A visual analogue scale (VAS) was used to assess the patient's self-reported symptoms of cancer over the intervention and follow-up periods. Following treatment, VAS scores' analysis revealed beneficial effects on pain, vomiting, dyspnoea, fatigue, anorexia, insomnia, daily activity and psychological calmness. These improvements were maintained over the two-week follow-up phase. After the first Qi therapy session, the patient discontinued medication and could sit by himself; after the fourth session, the patient was able to walk and use the toilet without assistance (improvement in KPS: 70: care for self, unable to perform normal activity or to do active work). Although limited by the single case study approach, our results support previous studies on this topic and provide reasons to conduct controlled clinical trials.

Adult↗

Characterization of a bacteriocin produced by Enterococcus faecium GM-1 isolated from an infant.

AIM: To partially characterize the bacteriocin produced by the GM-1 strain of Enterococcus faecium, isolated from the faeces of a newborn human infant. METHODS AND RESULTS: The bacteriocin produced by E. faecium GM-1 showed a broad spectrum of activity against indicator strains of Escherichia coli, Staphylococcus aureus, Vibrio spp., Salmonella typhimurium, Listeria monocytogenes, Lactobacillus acidophilus, and Streptococcus thermophilus. Treatment of the GM-1 bacteriocin with proteolytic enzymes reduced its inhibitory activities. The bacteriocin was stable at 100 degrees C for 20 min and displayed inhibitory activity at neutral pH. The optimal production of bacteriocin from E. faecium GM-1 was obtained when the culture conditions were pH 6.0-6.5 and 35-40 degrees C. The inhibitory activity of the bacteriocin was not substantially changed by the use of different carbon sources in the media, except when galactose was substituted for glucose. The use of a sole nitrogen source caused a decrease in inhibitory activity. A bacteriocin gene similar to enterocin P was identified from the total DNA of E. faecium GM-1 by PCR and direct sequencing methods. CONCLUSION: E. faecium GM-1, which was isolated from the faeces of a newborn baby, produces an enterocin P-like bacteriocin with inhibitory activity against Gram-positive and Gram-negative bacteria, including food-borne pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: E. faecium GM-1, isolated from infant faeces, produces a new bacteriocin that is similar to enterocin P. This bacteriocin is heat stable and has a broad antibacterial spectrum that includes both Gram-positive and Gram-negative bacteria.

Amino Acid Sequence↗