NICHE DYNAMICS OF KOREAN CIVIC ORGANIZATIONS: 1981~2003

This study tried to examine the development of civic organizations in Korea in terms of their changing membership niche. Based on the idea of Blau space proposed by McPherson ( , 2004 , we applied the theory of organization ecology We measured and examined the trend of niche width of civic organizations to see if growth in numbers of civic organizations was accompanied by the expansion of niche width. The results show that width of membership niche have increased in terms of occupation but not in terms of educational background. The results for the age niche are mixed in that the membership niche of labor union and vocation organizatio

Niche Dynamics of Korean Civic Organizations : 1981~2003

This study tried to examine the development of civic organizations in Korea in terms of their changing membership niche. Based on the idea of Blau space proposed by McPherson (1984, 2004), we applied the theory of organization ecology (Hannan and Freeman, 1989; Caroll and Hannan, 2000) to the development of Korean civic organizations. We measured and examined the trend of niche width of civic organizations to see if growth in numbers of civic organizations was accompanied by the expansion of niche width. The results show that width of membership niche have increased in terms of occupation but not in terms of educational background. The results for the age niche are mixed in that the membership niche of labor union and vocation organization expanded while that of ryonko and religious organization shrank over time. we also calculated the degree of niche overlap over time and examined the trend. The results show non-linear trend of initial rise and slight decline toward the end of observation period. The rise of niche overlap implies that civic organizations face potential competition for recruiting members

Clinical Characteristics and Risk Factors for Nosocomial Candidemia in Medical Intensive Care Units: Experience in a Single Hospital in Korea for 6.6 Years

The aim of this study was to determine candidemia incidence among patients in a medical intensive-care unit (MICU) and the associated mortality rate and to identify risk factors associated with candidemia. We retrospectively performed a 1:3 matched case-control study of MICU patients with candidemia. Controls were matched for sex, age, and Acute Physiology and Chronic Health Evaluation (APACHE) II score. Candidemia incidence was 9.1 per 1,000 admissions. The most common pathogen was Candida albicans. Crude mortality was 96% among candidemia patients and 52% among controls (P<0.001). Mortality differed significantly between the groups according to Kaplan-Meier survival analysis (P=0.024). Multivariate analysis identified the following independent risk factors for candidemia: central venous catheterization (odds ratio [OR] = 3.2, 95% confidence interval [CI]=1.2-9.0), previous steroid therapy (OR=4.7, 95% CI=1.8-12.1), blood transfusion during the same admission period (OR=6.3, 95% CI=2.4-16.7), and hepatic failure upon MICU admission (OR=6.9, 95% CI=1.7-28.4). In conclusion, we identify an additional independent risk factor for candidemia, the presence of hepatic failure on MICU admission. Therefore, increased awareness of risk factors, including hepatic failure, is necessary for the management of candidemia

Intrahepatic extramedullary hematopoiesis mimicking a hypervascular hepatic neoplasm on dynamic- and SPIO-enhanced MRI

We present a rare case of a focal intrahepatic extramedullary hematopoiesis (EMH) that mimicked a hypervascular hepatic neoplasm in a 33-year-old woman with idiopathic myelofibrosis. The lesion showed homogeneous and persistent enhancement on both contrast-enhanced CT and gadolinium-enhanced dynamic MR imaging. The lesion did not demonstrate an apparent signal drop on a T2-weighted sequence following administration of a superparamagnetic iron-oxide agent (SHU 555A). A hepatocellular adenoma was the initial radiological diagnosis. To the best of our knowledge, this is the first report of a histopathologically proven intrahepatic EMH evaluated with dynamic- and SPIO-enhanced MRI

Frequency and clinical implications of the isolation of rare nontuberculous mycobacteria

Background: To date, more than 125 species of nontuberculous mycobacteria (NTM) have been identified. In this study, we investigated the frequency and clinical implication of the rarely isolated NTM from respiratory specimens. Methods: Patients with NTM isolated from their respiratory specimens between July 1, 2010 and June 31, 2012 were screened for inclusion. Rare NTM were defined as those NTM not falling within the group of eight NTM species commonly identified at our institution: Mycobacterium avium, M. intracellulare, M. abscessus, M. massiliense, M. fortuitum, M. kansasii, M. gordonae, and M. peregrinum. Clinical, radiographic and microbiological data from patients with rare NTM were reviewed and analyzed. Results: During the study period, 73 rare NTM were isolated from the respiratory specimens of 68 patients. Among these, M. conceptionense was the most common (nine patients, 12.3%). The median age of the 68 patients with rare NTM was 68 years, while 39 of the patients were male. Rare NTM were isolated only once in majority of patient (64 patients, 94.1%). Among the four patients from whom rare NTM were isolated two or more times, only two showed radiographic aggravation caused by rare NTM during the follow-up period. Conclusions: Most of the rarely identified NTM species were isolated from respiratory specimens only once per patient, without concomitant clinical aggravation. Clinicians could therefore observe such patients closely without invasive work-ups or treatment, provided the patients do not have decreased host immunity towards mycobacteriaPeer Reviewe

High-intensity Focused Ultrasound Ablation of Soft-tissue Tumors and Assessment of Treatment Response with Multiparametric Magnetic Resonance Imaging: Preliminary Study Using Rabbit VX2 Tumor Model

BackgroundHigh-intensity focused ultrasound (HIFU) is an emerging technique for noninvasive ablative treatment. However, HIFU has rarely been performed for the treatment of soft-tissue tumors. Thus, we aimed to assess the feasibility and safety of performing extracorporeal HIFU for the treatment of soft-tissue tumor. The treatment response was assessed using functional magnetic resonance imaging (MRI) techniques.Materials and methodsIn the rabbit VX2 intramuscular tumor model, HIFU was performed using an extracorporeal HIFU device (YDME FEP-BY02) by varying the electric power from 50 to 400 W, with the other parameters being fixed. The HIFU beam was insonated to one layer of focal spots having a depth of 8 mm. The degree of ablation was evaluated by histological examination and functional MRI techniques including dynamic contrast-enhanced MRI (DCE-MRI) and apparent diffusion coefficient (ADC) map. The presence of skin burn was also evaluated.ResultsApplying HIFU with an electric power of 200 W discretely produced the ablation zone without skin burn as planned before treatment (maximal depth: 8–9 mm), which shows the suitability of using HIFU (with 200 W electric power) for the treatment of soft-tissue tumors. By contrast, HIFU with an electric power of 100 W produced an ill-marginated ablation zone with internal residual tumor foci, and HIFU with 300–400 W produced ablation zones with a maximum depth of 13–24 mm, which far exceeded the planned depth and caused skin burn. Perfusion maps of DCE-MRI demonstrated the devascularized ablation zone more conspicuously than conventional contrast-enhanced T1-weighted images, and ADC map demonstrated the surrounding edema or granulation tissue better than conventional T2-weighted images.ConclusionExtracorporeal HIFU treatment for soft-tissue tumor may be a feasible approach with adjustment of input energy level. For post-treatment assessment, functional MRI techniques including DCE-MRI and ADC map may be useful and complementary to conventional MRI