The association of low muscle mass with soluble receptor for advanced glycation end products (sRAGE): The Korean Sarcopenic Obesity Study (KSOS).

BACKGROUND: Advanced glycation end products (AGEs) are accumulated with aging in various tissues of humans. The soluble receptor for AGEs (sRAGE) exerts a protective role against the development of aging-related chronic disorders by neutralizing the action of AGEs. We investigated the implication of sRAGE on low muscle mass in Asian men and women. METHODS: This cross-sectional study included a 390-participant, nondiabetic subcohort recruited within the framework of the Korean Sarcopenic Obesity Study, an ongoing prospective cohort study. Low muscle mass was defined based on the distribution of appendicular skeletal muscle mass divided by body mass index, as proposed by the Foundation for the National Institutes Sarcopenia Project. RESULTS: Serum sRAGE levels were significantly lower in participants with low muscle mass than in participants without low muscle mass (0.76 [0.60-1.00] ng/mL vs 0.87 [0.67-1.15] ng/mL, P = .005). In age- and sex-adjusted correlation analyses, appendicular skeletal muscle mass divided by body mass index was associated with sRAGE (r = 0.109, P = .037). Furthermore, decreased circulating levels of sRAGE are independently associated with low muscle mass (odds ratio = 0.254, P = .002) after adjusting for confounding factors, including insulin resistance and inflammatory markers. CONCLUSIONS: The present study shows that a low circulating level of sRAGE may be an independent risk factor for the presence of low muscle mass.

Relationships between sarcopenic obesity and insulin resistance, inflammation, and vitamin D status: the Korean Sarcopenic Obesity Study.

OBJECTIVE: It has been suggested that insulin resistance, low-grade inflammation and vitamin D deficiency are associated with obesity and sarcopenia. However, their relationships with sarcopenic obesity (SO) are unclear. We evaluated the impact of homoeostasis model assessment of insulin resistance (HOMA-IR), high-sensitivity C-reactive protein (hsCRP) and 25-hydroxyvitamin D (25[OH]D) levels on SO in Korean adults. STUDY SUBJECT/MEASUREMENTS: This study included 493 apparently healthy adults (180 men and 313 women) enrolled in the Korean Sarcopenic Obesity Study. Sarcopenia was defined as a skeletal muscle mass index (SMI) of 1 SD below the sex-specific mean value for a young reference group. Obesity was defined as a visceral fat area (VFA) ≥100 cm(2) . We classified the participants into four sarcopenia/obesity groups based on both SMI and VFA. RESULTS: The prevalence of SO was 17·8% in men and 24·9% in women. In women, the SO group had higher HOMA-IR and hsCRP levels compared with the non-SO group. In men, the 25[OH]D levels were significantly lower in the SO group than the non-SO group. Both hsCRP and HOMA-IR levels were negatively correlated with SMI and positively correlated with VFA in both men and women, whereas 25[OH]D levels were positively correlated with SMI in both men and women. Multiple binary logistic regression analysis showed that HOMA-IR and 25[OH]D levels were independently associated with SO in men, while HOMA-IR and hsCRP were significant factors predicting SO in women. CONCLUSION: Insulin resistance, inflammation and vitamin D deficiency were associated with SO in a Korean adult population.

The association of Klotho gene polymorphism with the mortality of patients on maintenance dialysis.

Despite medical progress, high morbidity and mortality rates have persisted in patients with end-stage renal disease (ESRD). The role in atherosclerosis and cardiovascular disease of klotho, an aging process-related gene, has been highlighted. Genetic variation in klotho has been reported to be a risk factor for coronary artery disease and ischemic stroke. Regarding the significance of cardiovascular disease for the outcome of ESRD patients, we investigated whether genetic variation of klotho was associated with mortality in ESRD patients on hemodialysis. 478 patients on maintenance hemodialysis for more than 3 months at dialysis facilities affiliated with the Western Dialysis Physician Association were enrolled in September 2004. Patient survival was checked annually until September 2007. Genotypings of klotho in terms of G395A in the promoter region, C1818T in exon 4, and KL-VS was performed. 45 deaths (11.2%) occurred over 3 years. Mortality was higher in the GA+AA group than in the GG group (18.9% vs. 6.7%, respectively, p < 0.001). Kaplan-Meier analysis also revealed that the survival of the GA+AA group was worse than that of GG group (p = 0.002). Cox's proportional hazards regression analysis showed that age, A allele carrier status in G395A of klotho, hemoglobin, albumin and HDL cholesterol levels were the significant factors affecting survival of hemodialysis patients. The A allele of the G395A polymorphism of klotho may be associated with the risk of mortality in Korean hemodialysis patients. Age, hemoglobin, albumin and HDLC were also significant prognostic factors for survival in the present study.

Can the prostate risk calculator based on Western population be applied to Asian population?

BACKGROUND: We developed a korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy using clinical and laboratory data from a Korean male population (http://pcrc.korea.ac.kr). We compared its performance to prostate-specific antigen (PSA) testing and the Prostate Risk Calculator 3 (PRC 3) based on data from the Dutch part of European Randomized Study of Screening for Prostate Cancer (ERSPC), which predicts biopsy results for previously unscreened men. METHODS: Data were collected from 602 Korean men who were previously unscreened and underwent initial ten-core prostate biopsies. Multiple logistic regression analysis was performed to determine the significant predictors. Area under the receiver operating characteristic curve (AUC) and calibration plots of both calculators were evaluated. RESULTS: Prostate cancer (PCa) was detected in 172 (28.6%) men. Independent predictors of a positive biopsy included advanced age, elevated PSA levels, reduced volume of the transition zone, and abnormal digital rectal examination findings. The AUC of the KPCRC was higher than the PRC 3 and PSA alone on internal and external validation. Calibration plots of the KPCRC showed better performance than the other models on internal and external validation. Applying a cut-off of 10% of KPCRC implied that 251 of the 602 men (42%) would not have been biopsied and that 12 of the 172 PCa cases (7%) would not have been diagnosed. CONCLUSIONS: The KPCRC improves the performance of the PRC 3 and PSA testing in predicting Korean population's risk of PCa. It implies that Asian populations need their own risk calculators for PCa.

The differential relationship between fat mass and bone mineral density by gender and menopausal status.

Osteoporosis and obesity are important public health problems in an aging society. We investigated the differential impacts of fat on bone mineral density (BMD) according to gender and menopausal status. We analyzed the baseline data of an ongoing observational cohort study, including a total of 502 healthy subjects 20-88 years of age (144 men, 159 premenopausal women, 199 postmenopausal women). Body composition and fat mass were measured using computed tomography and dual energy X-ray absorptiometry (DXA). BMD was measured at lumbar spines using DXA. In men and postmenopausal women, there was no significant correlation between fat and bone parameters after adjusting for age and body weight. However, in premenopausal women, BMD had significant negative correlations with waist circumference, total fat area, subcutaneous fat area, appendicular fat mass and percentage fat mass after adjusting for age and body weight. Furthermore, only in premenopausal women, the subjects with the highest quartile of percentage fat mass had the lowest BMD even after adjusting for confounding factors including age, body weight, physical activity, alcohol use and smoking history. Multiple linear regression analysis showed that percentage fat mass was a significant negative decisive factor for BMD in premenopausal women. Our study showed the differential relationship between fat mass and BMD according to gender and menopausal status. Only in premenopausal women did fat mass have a significant negative effect on bone mass. This result suggests the importance of reducing fat mass in order to achieve peak bone mass in young adult women.

Rapid adaptation of robotic gastrectomy for gastric cancer by experienced laparoscopic surgeons.

BACKGROUND: Robotic surgery for gastric cancer patients has been increasing because of its many advantages over conventional laparoscopic surgery. Despite the suggestion that robotic surgery may lessen the learning curve for complex laparoscopic procedures, little is known about the learning curve for robotic gastrectomy. This study aimed to assess the learning curve of robotic gastrectomy for patients with cancer by analyzing the operation time. METHODS: The first 20 consecutive cases of robot-assisted distal gastrectomy with lymphadenectomy for gastric cancer performed by three experienced laparoscopic surgeons' using the da Vinci system were collected and reviewed. A nonlinear least-squares method was developed and used to analyze the learning curves. RESULTS: Overall, the mean operation time was 247.3 ± 45.7 min, depending on each surgeon's laparoscopic experience and the patient's characteristics. After control was used for confounding factors, the stabilized operation time decreased to 211.8 min. The operation time stabilized at 8.2 cases and was reduced 111.4 min from the first case. A stable operation time was reached in 9.6 cases by surgeon A, in 18.1 cases by surgeon B, and in 6 cases by surgeon C. The stable operation time was 149.2 min for surgeon A, 127.1 min for surgeon B, and 236.8 min for surgeon C, and the reduction in operation time from the first case to stabilization was 233 min for surgeon A, 76.7 min for surgeon B, and 154.6 min for surgeon C. CONCLUSIONS: Surgeons with sufficient experience in laparoscopic gastrectomy can rapidly overcome the learning curve for robotic gastrectomy. In addition, the surgeon's experience with laparoscopic gastrectomy affects the operation time after stabilization and the reduction in operation time.

Initial biopsy outcome prediction in Korean patients-comparison of a noble web-based Korean prostate cancer risk calculator versus prostate-specific antigen testing.

We developed and validated a novel Korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy in a Korean population. Data were collected from 602 Koreans who underwent initial prostate biopsies due to an increased level of prostate-specific antigen (PSA), a palpable nodule upon digital rectal examination (DRE), or a hypoechoic lesion upon transrectal ultrasound (TRUS). The clinical and laboratory variables were analyzed by simple and multiple logistic regression analysis. The area under the receiver operating characteristic curve (AUC) was computed to compare its performance to PSA testing alone. Prostate cancer was detected in 172 (28.6%) men. Independent predictors included age, DRE findings, PSA level, and prostate transitional zone volume. We developed the KPCRC using these variables. The AUC for the selected model was 0.91, and that of PSA testing alone was 0.83 (P < 0.001). The AUC for the selected model with an additional dataset was 0.79, and that of PSA testing alone was 0.73 (P = 0.004). The calculator is available on the website: http://pcrc.korea.ac.kr. The KPCRC improved the performance of PSA testing alone in predicting the risk of prostate cancer in a Korean population. This calculator would be a practical tool for physicians and patients.

Cutoff points of abdominal obesity indices in screening for non-alcoholic fatty liver disease in Asians.

BACKGROUND/AIMS: Abdominal obesity is associated with metabolic syndrome and non-alcoholic fatty liver disease (NAFLD). Although there have been many studies to determine the optimal cutoff points of waist circumference or visceral fat area in screening for metabolic syndrome, there have been no reports to establish adequate cutoff points of abdominal obesity indices in screening for NAFLD. Therefore, we examined the appropriate cutoff points of abdominal obesity indices associated with NAFLD in Korean men and women using receiver operating characteristic (ROC) curve analysis. Furthermore, we compared the usefulness of various abdominal obesity indices measured using computed tomography (CT), dual-energy X-ray absorptiometry (DXA) and anthropometric parameters for detecting NAFLD. METHODS: We analysed the baseline data of an ongoing prospective, observational cohort study, including a total of 456 healthy subjects 20-88 years of age. NAFLD was diagnosed by unenhanced CT using the liver attenuation index. RESULTS: All ROC curves of waist circumference, waist-to-height ratio, DXA-measured trunk fat mass and CT-measured visceral fat area were significantly above the diagonal line. There were no significant differences in the area under the curve values among these abdominal obesity indices in each gender. The appropriate cutoff point of waist circumference in screening for NAFLD was 89 cm for men and 84 cm for women and the optimal cutoff point of waist-to-height ratio was 0.52 for men and 0.53 for women with very high negative predictive values. CONCLUSIONS: The simple anthropometric parameters, such as waist circumference and waist-to-height ratio, are as useful as DXA and CT for predicting NAFLD in Korean adults.

Advanced gastric cancer in the middle one-third of the stomach: Should surgeons perform total gastrectomy?

BACKGROUND AND OBJECTIVES: To determine which optimal surgical procedure for middle-third advanced gastric cancer (AGC) based on comparative study of the long-term prognosis between total gastrectomy (TG) and distal gastrectomy (DG). METHODS: Between March 1993 and December 2005, 402 patients with middle-third AGC who underwent gastric resection were enrolled in this study. We analyzed the long-term prognosis according to the length of the proximal resection margin (PRM) and the extent of gastric resection, and determined independent prognostic factors. RESULTS: TG was performed in 244 patients (60.7%) and DG was performed in 158 patients (39.3%). There were no significant differences in the 5-year survival rates according to the length of PRM. The 5-year survival rates of patients who underwent DG were significantly higher than the rates of the patients who underwent TG in curative cases (67.8% vs. 58.4%, P = 0.037). Nevertheless, there was no significant difference in the stage-stratified survival rates according to the extent of gastric resection. Multivariate analysis revealed that surgical curability, extent of lymphadenectomy, and stage were independent prognostic factors. CONCLUSION: If curative resection can be performed, the long-term prognosis of patients with middle-third AGC was not affected by the length of PRM or the extent of gastric resection.

Analysis of callus pattern of tibia lengthening in achondroplasia and a novel method of regeneration assessment using pixel values.

OBJECTIVE: To relate morphology of new bone formation to outcome after tibial lengthening performed in patients with achondroplasia. MATERIAL AND METHODS: A retrospective analysis of 60 tibial segments in 30 achondroplasia patients was performed. There were 22 female patients and eight male patients, with a mean age of 9.8 years. New bone formation was classified by shape, homogeneity and density. Pixel values in relation to original bone were measured using a picture-archiving communication system (PACS). Clinical outcome was described by the external fixator and maturation indices. RESULTS: Mean lengthening was 9.2 cm (range 3-12.7 cm). The mean external fixator index was 23.4 (range 15.1-50). The mean maturation index was 12.3 days/cm (range 6-40 days/cm). Homogeneous pathways were associated with the best clinical results (fixator index 20.4, maturation index 10.8), followed by heterogeneous pathway (external fixator index 26.5, maturation index 16.8) and radiolucent pathway (fixator index 31.2, maturation index 21.4). Both cylindrical (external fixator index 25.2, maturation index 14.5) and concave (external fixator index 26.6, maturation index 16.3) callus shapes were favourable. Mineralization of new bone became equal to that of normal bone within 16 weeks (mean) for homogeneous pathway, 12 weeks for heterogeneous pathway and 32 weeks for lucent pathway. CONCLUSION: The type of new bone formation seen on radiographs is related to clinical outcome, with homogeneous pathways being the most favourable ones.

Factors influencing the severity of menopause symptoms in Korean post-menopausal women.

We have relatively limited knowledge of symptomatic aspects of the postmenopause, rather than perimenopause. We tried to determine the factors associated with experiencing menopausal symptoms by Korean postmenopausal women. A total of 657 Korean women who underwent a natural menopause completed multiple questionnaires, which included questions regarding their attitudes to menopause, depressive symptoms, state anxiety, self-esteem, dyadic relationships, sociodemographic variables, and 11-item Menopause Rating Scale (MRS). Multiple regression analyses were performed to collectively examine the relative impact of each independent variable on the quality of life, as determined by the MRS. Decreased severity of menopausal symptoms was associated with more time spent in education, an employed status, a history of pregnancy, longer postmenopausal duration, positive attitudes to menopause, higher state anxiety, heightened self-esteem, and higher dyadic consensus. Increased severity of menopausal symptoms was also associated with absence of a partner, alcohol consumption, a history of hormone replacement therapy, a history of probable premenstrual dysphoric disorder, and increased severity of depressive symptoms. Sociodemographic characteristics, lifestyle factors, premenstrual dysphoric disorder, attitudes to menopause, a dyadic relationship with a partner, and the inner psychological status can be associated with the severity of menopause symptoms specifically in Korean postmenopausal women.

Comparison between Statistical Models and Machine Learning Methods on Classification for Highly Imbalanced Multiclass Kidney Data.

This study aims to compare the classification performance of statistical models on highly imbalanced kidney data. The health examination cohort database provided by the National Health Insurance Service in Korea is utilized to build models with various machine learning methods. The glomerular filtration rate (GFR) is used to diagnose chronic kidney disease (CKD). It is calculated using the Modification of Diet in Renal Disease method and classified into five stages (1, 2, 3A and 3B, 4, and 5). Different CKD stages based on the estimated GFR are considered as six classes of the response variable. This study utilizes two representative generalized linear models for classification, namely, multinomial logistic regression (multinomial LR) and ordinal logistic regression (ordinal LR), as well as two machine learning models, namely, random forest (RF) and autoencoder (AE). The classification performance of the four models is compared in terms of accuracy, sensitivity, specificity, precision, and F1-Measure. To find the best model that classifies CKD stages correctly, the data are divided into a 10-fold dataset with the same rate for each CKD stage. Results indicate that RF and AE show better performance in accuracy than the multinomial and ordinal LR models when classifying the response variable. However, when a highly imbalanced dataset is modeled, the accuracy of the model performance can distort the actual performance. This occurs because accuracy is high even if a statistical model classifies a minority class into a majority class. To solve this problem in performance interpretation, we not only consider accuracy from the confusion matrix but also sensitivity, specificity, precision, and F-1 measure for each class. To present classification performance with a single value for each model, we calculate the macro-average and micro-weighted values for each model. We conclude that AE is the best model classifying CKD stages correctly for all performance indices.

Testing Lack of Symmetry in Spatial-Temporal Processes.

Symmetry and separability of spatial-temporal covariances are the main assumptions that are frequently taken for granted in most applications because of the simplicity of constructing covariance structure. However, many studies in environmental sciences show that real data have complex spatial-temporal dependency structures resulting from lack of symmetry or violation of other standard assumptions of the covariance function. In this study, we propose new formal tests for lack of symmetry by using spectral representations of the spatial-temporal covariance functions. The advantage of the proposed tests is that classical analysis of variance (ANOVA) models can be used for detecting lack of symmetry inherent in spatial-temporal processes. We evaluate the performance of the tests with simulation studies and we apply them to air pollution data.

Comparisons of three different methods for defining sarcopenia: An aspect of cardiometabolic risk.

Appraisal of muscle mass is important when considering the serious consequences of sarcopenia in an aging society. However, the associations between sarcopenia and its clinical outcomes might vary according to the method applied in its diagnosis. We compared the relationships between cardiometabolic risk parameters and sarcopenia defined according to three different diagnostic methods using dual-energy X-ray absorptiometry (DXA) and computed tomography (CT). Appendicular skeletal muscle mass (ASM) adjusted by height squared and BMI (ASM/height2 and ASM/BMI) measured using DXA and thigh muscle cross-sectional area (tmCSA) adjusted by weight (tmCSA/weight) measured using CT were used as indices of muscle mass. Sarcopenia was defined as two standard deviations below either the mean ASM/height2, ASM/BMI, or tmCSA/weight of a young reference group. ASM/BMI and tmCSA/weight showed a negative relationship with several components of metabolic syndrome and HOMA-IR, whereas ASM/height2 was positively associated with theses cardiometabolic risk factors. Logistic regression analyses demonstrated that ASM/BMI-defined sarcopenia was significantly associated with increased HOMA-IR (P = 0.01) and prevalence of visceral obesity (P = 0.03) and metabolic syndrome (P = 0.025), while ASM/height2- and tmCSA/weight-defined sarcopenia were not. ASM/BMI-defined sarcopenia exhibits a closer relationship with cardiometabolic risk factors than does ASM/height2- or tmCSA/weight-defined sarcopenia.

Development and External Validation of the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer: Comparison with Two Western Risk Calculators in an Asian Cohort.

PURPOSE: We developed the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer (KPCRC-HG) that predicts the probability of prostate cancer (PC) of Gleason score 7 or higher at the initial prostate biopsy in a Korean cohort (http://acl.snu.ac.kr/PCRC/RISC/). In addition, KPCRC-HG was validated and compared with internet-based Western risk calculators in a validation cohort. MATERIALS AND METHODS: Using a logistic regression model, KPCRC-HG was developed based on the data from 602 previously unscreened Korean men who underwent initial prostate biopsies. Using 2,313 cases in a validation cohort, KPCRC-HG was compared with the European Randomized Study of Screening for PC Risk Calculator for high-grade cancer (ERSPCRC-HG) and the Prostate Cancer Prevention Trial Risk Calculator 2.0 for high-grade cancer (PCPTRC-HG). The predictive accuracy was assessed using the area under the receiver operating characteristic curve (AUC) and calibration plots. RESULTS: PC was detected in 172 (28.6%) men, 120 (19.9%) of whom had PC of Gleason score 7 or higher. Independent predictors included prostate-specific antigen levels, digital rectal examination findings, transrectal ultrasound findings, and prostate volume. The AUC of the KPCRC-HG (0.84) was higher than that of the PCPTRC-HG (0.79, p<0.001) but not different from that of the ERSPCRC-HG (0.83) on external validation. Calibration plots also revealed better performance of KPCRC-HG and ERSPCRC-HG than that of PCPTRC-HG on external validation. At a cut-off of 5% for KPCRC-HG, 253 of the 2,313 men (11%) would not have been biopsied, and 14 of the 614 PC cases with Gleason score 7 or higher (2%) would not have been diagnosed. CONCLUSIONS: KPCRC-HG is the first web-based high-grade prostate cancer prediction model in Korea. It had higher predictive accuracy than PCPTRC-HG in a Korean population and showed similar performance with ERSPCRC-HG in a Korean population. This prediction model could help avoid unnecessary biopsy and reduce overdiagnosis and overtreatment in clinical settings.

High Incidence of Breast Cancer in Light-Polluted Areas with Spatial Effects in Korea.

We have reported a high prevalence of breast cancer in light-polluted areas in Korea. However, it is necessary to analyze the spatial effects of light polluted areas on breast cancer because light pollution levels are correlated with region proximity to central urbanized areas in studied cities. In this study, we applied a spatial regression method (an intrinsic conditional autoregressive [iCAR] model) to analyze the relationship between the incidence of breast cancer and artificial light at night (ALAN) levels in 25 regions including central city, urbanized, and rural areas. By Poisson regression analysis, there was a significant correlation between ALAN, alcohol consumption rates, and the incidence of breast cancer. We also found significant spatial effects between ALAN and the incidence of breast cancer, with an increase in the deviance information criterion (DIC) from 374.3 to 348.6 and an increase in R2 from 0.574 to 0.667. Therefore, spatial analysis (an iCAR model) is more appropriate for assessing ALAN effects on breast cancer. To our knowledge, this study is the first to show spatial effects of light pollution on breast cancer, despite the limitations of an ecological study. We suggest that a decrease in ALAN could reduce breast cancer more than expected because of spatial effects.

High prevalence of breast cancer in light polluted areas in urban and rural regions of South Korea: An ecologic study on the treatment prevalence of female cancers based on National Health Insurance data.

It has been reported that excessive artificial light at night (ALAN) could harm human health since it disturbs the natural bio-rhythm and sleep. Such conditions can lead to various diseases, including cancer. In this study, we have evaluated the association between ALAN and prevalence rates of cancer in females on a regional basis, after adjusting for other risk factors, including obesity, smoking, alcohol consumption rates and PM10 levels. The prevalence rates for breast cancer were found to be significantly associated with ALAN in urban and rural areas. Furthermore, no association was found with ALAN in female lung, liver, cervical, gastric and colon cancer. Despite the limitations of performing ecological studies, this report suggests that ALAN might be a risk factor for breast cancer, even in rural areas.

Vulnerabilities to Temperature Effects on Acute Myocardial Infarction Hospital Admissions in South Korea.

Most previous studies have focused on the association between acute myocardial function (AMI) and temperature by gender and age. Recently, however, concern has also arisen about those most susceptible to the effects of temperature according to socioeconomic status (SES). The objective of this study was to determine the effect of heat and cold on hospital admissions for AMI by subpopulations (gender, age, living area, and individual SES) in South Korea. The Korea National Health Insurance (KNHI) database was used to examine the effect of heat and cold on hospital admissions for AMI during 2004-2012. We analyzed the increase in AMI hospital admissions both above and below a threshold temperature using Poisson generalized additive models (GAMs) for hot, cold, and warm weather. The Medicaid group, the lowest SES group, had a significantly higher RR of 1.37 (95% CI: 1.07-1.76) for heat and 1.11 (95% CI: 1.04-1.20) for cold among subgroups, while also showing distinctly higher risk curves than NHI for both hot and cold weather. In additions, females, older age group, and those living in urban areas had higher risks from hot and cold temperatures than males, younger age group, and those living in rural areas.

Lessons learned from a comparative analysis of surgical outcomes of and learning curves for laparoscopy-assisted distal gastrectomy.

PURPOSE: Before expanding our indications for laparoscopic gastrectomy to advanced gastric cancer and adopting reduced port laparoscopic gastrectomy, we analyzed and audited the outcomes of laparoscopy-assisted distal gastrectomy (LADG) for adenocarcinoma; this was done during the adoptive period at our institution through the comparative analysis of short-term surgical outcomes and learning curves (LCs) of two surgeons with different careers. MATERIALS AND METHODS: A detailed comparative analysis of the LCs and surgical outcomes was done for the respective first 95 and 111 LADGs performed by two surgeons between July, 2006 and June, 2011. The LCs were fitted by using the non-linear ordinary least squares estimation method. RESULTS: The postoperative morbidity and mortality rates were 14.6% and 0.0%, respectively, and there was no significant difference in the morbidity rates (12.6% vs. 16.2%, P=0.467). More than 25 lymph nodes were retrieved by each surgeon during LADG procedures. The LCs of both surgeons were distinct. In this study, a stable plateau of the LC was not achieved by both surgeons even after performing 90 LADGs. CONCLUSIONS: Regardless of the experience with gastrectomy or laparoscopic surgery for other organs, or the age of surgeon, the outcome was quite acceptable; the learning process differ according to the surgeon's experience and individual characteristics.

Short-term effect of temperature on daily emergency visits for acute myocardial infarction with threshold temperatures.

BACKGROUND: The relationship between temperature and myocardial infarction has not been fully explained. In this study, we identified the threshold temperature and examined the relationship between temperature and emergency admissions due to MI in Korea. METHODS: Poisson generalized additive model analyses were used to assess the short-term effects of temperature (mean, maximum, minimum, diurnal) on MI emergency visits, after controlling for meteorological variable and air pollution (PM10, NO2). We defined the threshold temperature when the inflection point showed a statistically significant difference in the regression coefficients of the generalized additive models (GAMs) analysis. The analysis was performed on the following subgroups: geographical region, gender, age (<75 years or ≥ 75 years), and MI status (STEMI or non-STEMI). RESULTS: The threshold temperatures during heat exposure were for the maximum temperature as 25.5-31.5°C and for the mean temperature as 27.5-28.5°C. The threshold temperatures during cold exposure were for the minimum temperature as -2.5-1.5°C. Relative risks (RRs) of emergency visits above hot temperature thresholds ranged from 1.02 to 1.30 and those below cold temperature thresholds ranged from 1.01 to 1.05. We also observed increased RRs ranged from 1.02 to 1.65 of emergency visits when temperatures changes on a single day or on successive days. CONCLUSIONS: We found a relationship between temperature and MI occurrence during both heat and cold exposure at the threshold temperature. Diurnal temperature or temperature change on successive days also increased MI risk.