OBJECTIVES: This study demonstrates the feasibility of using a modified mixture of experts (ME) model with repeated measured tumoural Ktrans value to perform an automatic diagnosis of responder based on perfusion magnetic resonance imaging (MRI) of rectal cancer. METHODS: The data used in this study was obtained from 39 patients with primary rectal carcinoma who were scheduled for preoperative chemoradiotherapy. The modified ME model is a joint modeling of the ME model via the linear mixed effect model. First, we considered two local experts and a gating network, and the modified expert network as a liner mixed effect model. Afterward, the finding estimates were obtained via the expectation-maximization algorithm. All computation was performed by R-2.15.2. RESULTS: We found that two experts have different patterns. The feature of expert 1 (n = 10) had a higher baseline value and a lower slope than expert 2 (n = 29). A comparison of the estimated experts and responder/non-responder groups according to T-downstaging criteria showed that expert 1 had a more effect treatment responder than expert 2. CONCLUSIONS: A novel feature of this study is that it is an extension of classical ME models in case of repeatedly measured data. The proposed model has the advantages of flexibility and adaptability for identifying distinct subgroups with various time patterns, and it can be applied to biomedical data which is measured repeatedly, such as time-course microarray data or cohort data. This method can assist physicians as important diagnostic decision making mechanism.
Chemoradiotherapy ; Cohort Studies ; Decision Making ; Humans ; Joints ; Magnetic Resonance Angiography ; Magnetic Resonance Imaging ; Perfusion ; Pliability ; Rectal Neoplasms

PURPOSE: There is increasing attention to smart-learning as a new education paradigm. The purpose of this study was to identify the level of intention to use smart-based Continuing Nurse Education (CNE) and factors influencing intention to use smart-based CNE. METHODS: Participants were 486 nurses from 14 organizations, including 12 hospitals, a nurses association, and an office of education. Data were collected from November 5 to 18, 2014 using self-report questionnaires. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation, and stepwise multiple regression. RESULTS: The mean score for intention to use smart-based CNE was 6.34 out of 10. The factors influencing intention to use smart-based CNE were nursing informatics competency, current unit career, and smartphone addiction. These variables explained 10% of variance in intention to use smart-based CNE. CONCLUSION: The findings of this study suggest that efforts to enhance the nursing informatics competency of nurses could increase usage rate of smart-based CNE. The CNE policy makers will find this study very useful and the findings of this study will help to provide insight into the best way to develop smart-based CNE.
Administrative Personnel ; Education* ; Education, Continuing ; Humans ; Intention* ; Nursing Informatics

BACKGROUND: Treatment of diabetic foot infection remains difficult, due partly to defective neutrophil functions. Granulocyte-colony stimulating factor (G-CSF) increases neutrophil counts in peripheral blood and enhances neutrophil functions in healthy peoples and patients with hematologic diseases. We performed this study to evaluate neutrophil functions in diabetic patients with foot infections and the effect of rhG-CSF on neutrophil functions in vitro. METHODS: Twelve patients with diabetic foot infections and 12 normal volunteers were enrolled. Venous blood was collected in heparin-containing tubes, and neutrophils were isolated immediately. The isolated neutrophils were incubated with rhG-CSF (50 ng/mL) for 20 minutes. Assays of superoxide anion production of neutrophils were based on the reduction of ferricytochrome C. Assays of phagocytosis by neutrophils were done using Staphylococcus aureus and the weighted phagocytic index (WPI) was calculated by counting the number of phagocytosing neutrophils on the slides. RESULTS: Superoxide anion production of neutrophils in diabetic patients was 4.7 (unit: nmol/2105cells/30min), which was significantly lower than that of controls (7.6) (P<0.05). rhG-CSF increased the superoxide anion production of neutrophils to 9.8 in diabetic patients and to 15.6 in the controls (P<0.05). WPI in diabetic patients was 0.77, which was not significantly different from that of the controls (0.69). WPI was increased significantly by rhG-CSF in diabetic patients (0.88) and in controls (0.79). CONCLUSION: rhG-CSF enhanced neutrophil functions in vitro, which were evaluated by superoxide anion production and phagocytosis in diabetic patients with foot infections. These results suggest that rhG-CSF can be useful in the treatment of diabetic foot infections.
Cytochromes c ; Diabetic Foot ; Foot* ; Granulocyte Colony-Stimulating Factor ; Healthy Volunteers ; Hematologic Diseases ; Humans* ; Neutrophils* ; Phagocytosis ; Staphylococcus aureus ; Superoxides

OBJECTIVE: To determine whether quantitative perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) correlate with immunohistochemical markers of angiogenesis in rectal cancer. MATERIALS AND METHODS: Preoperative DCE-MRI was performed in 63 patients with rectal adenocarcinoma. Transendothelial volume transfer (Ktrans) and fractional volume of the extravascular-extracellular space (Ve) were measured by Interactive Data Language software in rectal cancer. After surgery, microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression scores were determined using immunohistochemical staining of rectal cancer specimens. Perfusion parameters (Ktrans, Ve) of DCE-MRI in rectal cancer were found to be correlated with MVD and VEGF expression scores by Spearman's rank coefficient analysis. T stage and N stage (negative or positive) were correlated with perfusion parameters and MVD. RESULTS: Significant correlation was not found between any DCE-MRI perfusion parameters and MVD (rs = -0.056 and p = 0.662 for Ktrans; rs = -0.103 and p = 0.416 for Ve), or between any DCE-MRI perfusion parameters and the VEGF expression score (rs = -0.042, p = 0.741 for Ktrans ; r = 0.086, p = 0.497 for Ve) in rectal cancer. TN stage showed no significant correlation with perfusion parameters or MVD (p > 0.05 for all). CONCLUSION: DCE-MRI perfusion parameters, Ktrans and Ve, correlated poorly with MVD and VEGF expression scores in rectal cancer, suggesting that these parameters do not simply denote static histological vascular properties.
Adult ; Aged ; Aged, 80 and over ; Contrast Media/*diagnostic use ; Female ; Follow-Up Studies ; Humans ; Immunohistochemistry ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Neoplasm Staging ; Neovascularization, Pathologic/diagnosis/metabolism ; Rectal Neoplasms/blood supply/*diagnosis/metabolism ; Retrospective Studies ; Tumor Markers, Biological/biosynthesis ; Vascular Endothelial Growth Factor A/*biosynthesis

OBJECTIVES: The mixture-of-experts (ME) network uses a modular type of neural network architecture optimized for supervised learning. This model has been applied to a variety of areas related to pattern classification and regression. In this research, we applied a ME model to classify hidden subgroups and test its significance by measuring the stiffness of the liver as associated with the development of liver cirrhosis. METHODS: The data used in this study was based on transient elastography (Fibroscan) by Kim et al. We enrolled 228 HBsAg-positive patients whose liver stiffness was measured by the Fibroscan system during six months. Statistical analysis was performed by R-2.13.0. RESULTS: A classical logistic regression model together with an expert model was used to describe and classify hidden subgroups. The performance of the proposed model was evaluated in terms of the classification accuracy, and the results confirmed that the proposed ME model has some potential in detecting liver cirrhosis. CONCLUSIONS: This method can be used as an important diagnostic decision support mechanism to assist physicians in the diagnosis of liver cirrhosis in patients.
Elasticity Imaging Techniques ; Humans ; Learning ; Liver ; Liver Cirrhosis ; Logistic Models

BACKGROUND: Enterococci have emerged in recent years as a frequent cause of life-threatening nosocomial infections. The emergence of vancomycin-resistant enterococci(VRE) presents as an increasingly important problem particularly in the treatment and the potential dissemination of vancomycin-resistance. The purpose of this study is to determine the phenotypes and genotypes of VRE isolated from five hospitals and to study the genetic relatedness among them. METHODS: Antimicrobial susceptibility patterns and amplification of vancomycin resistance genes were used for phenotyping and genotyping of 42 VRE isolates respectively. For 21 isolates with vanA or vanB gene, plasmid profiles and pulsed field gel electrophoresis(PFGE) patterns were analyzed for molecular epidemiologic study. RESULTS: Out of 42 isolates, 21 were identified as E. faecium, 6 as E. faecalis, 2 as E. avium, and 13 as E. casseliflavus. Phenotyping showed 14 isolates as VanA(33%), 7 as VanB(17%) and 21 as VanC(50 %). Genotyping resulted in 12 isolates as vanA(5 of E. faecalis and 7 of E. faecium) and 9 as vanB(all E. faecium). Genotyping results were concordant with phenotyping results except for the two E. faecium isolates of VanA which had vanB genotype. Intrahospital spread of the same strains was proven in three hospitals by plasmid profiles and PFGE analysis. CONCLUSION: The study demonstrated a considerable number of VRE isolates in Korea and intrahospital spread proven by molecular epidemiologic methods. Although VRE infection has been considered very rare in Korea, practical guidelines including restriction of vancomycin usage and surveillance, are warranted to prevent infection and dissemination of VRE.
Cross Infection ; Epidemiologic Methods ; Epidemiologic Studies ; Genotype ; Korea* ; Molecular Epidemiology* ; Phenotype ; Plasmids ; Vancomycin ; Vancomycin Resistance

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) has become a major pathogen of nosocomial infection. In Korea, incidence of MRSA is alarmingly high up to 70-80% of total S. aureus strains isolated from tertiary care hospitals. To investigate the mechanism of intra- and inter-hospital spread of MRSA, we evaluated the genetic relatedness of MRSA isolates recovered from 3 different hospitals in Korea. METHODS:30 MRSA isolates obtained from Samsung Medical Center(SMC), 37 MRSA isolates from Seoul National University Hospital (SNUH) and 40 MRSA isolates from Dankook University Hospital (DUH) were classified into clonal types on the basis of pulsed field gel electrophoresis(PFGE). RESULTS: Several PFGE patterns were predominant among the isolates from SMC(A-7/30[23.3%], B-6/30[20.0%], C-4/30[13.3%], G-3/30[10.0%]). The prevalent PFGE patterns were different between medical ICU(A-3/5[60.0%]) and newborn ICU(B-4/9[44.4%]). The major clone at SNUH was PFGE type A, which was identical with one of the dominant clones of SMC. The major clone at DUH was PFGE type B, which was identical with another dominant clone of SMC. Although MRSA strains from SMC, which caused clinical diseases belonged to major PFGE patterns more often than colonized strains, the association was not significant statistically. CONCLUSION: The presence of epidemic strains of MRSA suggests that epidemic MRSA clones may be originated from common sources and spread between different hospitals. Also, there may be virulence factors of stains or host factors, which could select specific strains.
Clone Cells ; Colon ; Coloring Agents ; Cross Infection ; Electrophoresis, Gel, Pulsed-Field ; Humans ; Incidence ; Infant, Newborn ; Korea* ; Methicillin Resistance* ; Methicillin-Resistant Staphylococcus aureus* ; Seoul ; Staphylococcus aureus ; Tertiary Healthcare ; Virulence Factors

This study was performed to evaluate the effect of granulocyte-colony stimulating factor on neutrophil functions in diabetic patients with active foot infections in vitro. Twelve diabetic patients with foot infections and 12 normal volunteers were enrolled. Neutrophils from peripheral blood were incubated with granulocyte colony-stimulating factor (G-CSF, 50 ng/mL) for 20 min. Superoxide production of neutrophils was measured by the reduction of ferricytochrome C. Neutrophil phagocytosis was assayed using Staphylococcus aureus and the weighted phagocytic index was calculated. Superoxide production of neutrophils in diabetic patients with foot infections was 7.7 (unit: nmol/2 x 10(5) cells/60 min), which was significantly lower than that in controls (12.0) (p<0.05). G-CSF increased neutrophil superoxide production to 12.1 in diabetic patients with foot infections and to 19.8 in controls (p<0.05 for each). Weighted phagocytic index in diabetic patients with foot infections was 0.77, which was not significantly different from that of the controls (0.69). Weighted phagocytic index was increased significantly by G-CSF to 0.88 in diabetic patients with foot infections and to 0.79 in controls (p<0.05 for each). In conclusion, G-CSF significantly enhanced neutrophil functions in diabetic patients with foot infections in vitro.
Adult ; Aged ; Bacterial Infections/immunology* ; Diabetes Mellitus/immunology* ; Female ; Foot Diseases/immunology* ; Granulocyte Colony Stimulating Factor, Recombinant/pharmacology* ; Human ; Male ; Middle Age ; Neutrophils/immunology ; Neutrophils/drug effects* ; Receptors, IgG/analysis ; Superoxides/metabolism

BACKGROUND AND OBJECTIVES: This study aimed to confirm the effects of traditional holidays on the incidence and outcomes of out-of-hospital cardiac arrest (OHCA) in South Korea. METHODS: We studied 95,066 OHCAs of cardiac cause from a nationwide, prospective study from the Korea OHCA Registry from January 2012 to December 2016. We compared the incidence of OHCA, in-hospital mortality, and neurologic outcomes between traditional holidays, Seollal (Lunar New Year's Day) and Chuseok (Korean Thanksgiving Day), and other day types (weekday, weekend, and public holiday). RESULTS: OHCA occurred more frequently on traditional holidays than on the other days. The median OHCA incidence were 51.0 (interquartile range [IQR], 44.0–58.0), 53.0 (IQR, 46.0–60.5), 52.5 (IQR, 45.3–59.8), and 60.0 (IQR, 52.0–69.0) cases/day on weekday, weekend, public holiday, and traditional holiday, respectively (p<0.001). The OHCA occurred more often at home rather than in public place, lesser bystander cardiopulmonary resuscitation (CPR) was performed, and the rate of cessation of CPR within 20 minutes without recovery of spontaneous circulation was higher on traditional holiday. After multivariable adjustment, traditional holiday was associated with higher in-hospital mortality (adjusted hazard ratio [HR], 1.339; 95% confidence interval [CI], 1.058–1.704; p=0.016) but better neurologic outcomes (adjusted HR, 0.503; 95% CI, 0.281–0.894; p=0.020) than weekdays. CONCLUSIONS The incidence of OHCAs was associated with day types in a year. It occurred more frequently on traditional holidays than on other day types. It was associated with higher in-hospital mortality and favorable neurologic outcomes than weekday.

BACKGROUND AND OBJECTIVES: This study aimed to confirm the effects of traditional holidays on the incidence and outcomes of out-of-hospital cardiac arrest (OHCA) in South Korea. METHODS: We studied 95,066 OHCAs of cardiac cause from a nationwide, prospective study from the Korea OHCA Registry from January 2012 to December 2016. We compared the incidence of OHCA, in-hospital mortality, and neurologic outcomes between traditional holidays, Seollal (Lunar New Year's Day) and Chuseok (Korean Thanksgiving Day), and other day types (weekday, weekend, and public holiday). RESULTS: OHCA occurred more frequently on traditional holidays than on the other days. The median OHCA incidence were 51.0 (interquartile range [IQR], 44.0–58.0), 53.0 (IQR, 46.0–60.5), 52.5 (IQR, 45.3–59.8), and 60.0 (IQR, 52.0–69.0) cases/day on weekday, weekend, public holiday, and traditional holiday, respectively (p<0.001). The OHCA occurred more often at home rather than in public place, lesser bystander cardiopulmonary resuscitation (CPR) was performed, and the rate of cessation of CPR within 20 minutes without recovery of spontaneous circulation was higher on traditional holiday. After multivariable adjustment, traditional holiday was associated with higher in-hospital mortality (adjusted hazard ratio [HR], 1.339; 95% confidence interval [CI], 1.058–1.704; p=0.016) but better neurologic outcomes (adjusted HR, 0.503; 95% CI, 0.281–0.894; p=0.020) than weekdays. CONCLUSIONS: The incidence of OHCAs was associated with day types in a year. It occurred more frequently on traditional holidays than on other day types. It was associated with higher in-hospital mortality and favorable neurologic outcomes than weekday.
Cardiopulmonary Resuscitation ; Epidemiology ; Heart Arrest ; Holidays ; Hospital Mortality ; Incidence ; Korea ; Mortality ; Out-of-Hospital Cardiac Arrest ; Prospective Studies