Kyoung-Ho Lee

Smoking increases rheumatoid arthritis susceptibility in individuals carrying the HLA–DRB1 shared epitope, regardless of rheumatoid factor or anti–cyclic citrullinated peptide antibody status

OBJECTIVEnSmoking is associated with rheumatoid arthritis (RA) in individuals with the HLA-DRB1 shared epitope (SE). SE alleles have been shown to be predominantly associated with anti-cyclic citrullinated peptide (anti-CCP)-positive RA. These risk factors have not been identified for anti-CCP-negative RA. The aim of this study was to investigate whether SE-containing HLA-DRB1 alleles, smoking, or the combination of these factors contributes to the development of RA, depending on the presence or absence of serologic markers, in a Korean population.nnnMETHODSnAll of the patients with RA (n =1,482) and all of the control subjects (n = 1,119) were Korean. Four-digit HLA-DRB1 typing was performed by a conventional polymerase chain reaction-sequence-based typing method. Information about smoking history was obtained through a questionnaire. The patients with RA were tested for anti-CCP antibodies and rheumatoid factor (RF).nnnRESULTSnThe SE alleles had significant effects on anti-CCP antibody and RF formation. The DRB1*0901 allele was associated with the presence of anti-CCP antibodies (odds ratio [OR] 2.49) and RF (OR 2.09). SE alleles and smoking were associated with both anti-CCP-positive and anti-CCP-negative RA. The combination of smoking and double copies of the SE allele increased the risk of anti-CCP-positive RA 36.11-fold and increased the risk of anti-CCP-negative RA 12.29-fold, compared with the risk among nonsmokers not carrying SE alleles. Interactions between SE alleles and smoking were observed for both anti-CCP-positive and RF-positive RA, although the associations of RF-positive RA could be consequences of the underlying anti-CCP antibody status.nnnCONCLUSIONnWe demonstrated that the combination of SE alleles and smoking is associated with RA susceptibility regardless of anti-CCP antibody or RF status, but that the combination shows stronger effects in anti-CCP-positive/RF-positive patients with RA than in anti-CCP-negative/RF-negative patients with RA. The SE-smoking interactions were present in anti-CCP-positive and RF-positive RA.

Age estimation by occlusal tooth wear

The purpose of the present investigation was to test the accuracy of a new scoring system in recording tooth wear for age estimation. The material consisted of dental stone casts of 383 volunteers who had sound premolars and molars with normal occlusion. The degree of occlusal wear for all premolar and molar teeth was scored with the new system. The high intra- and inter-examiner concordances showed that the new score system was very reliable. The degree of tooth wear showed a significant positive correlation with age in each and every examined tooth of both males and females. Tooth wear scores of males were higher than those of females. Calculating tables for age estimation were designed and the accuracy of age estimation was obtained with the General Linear Models procedures. Our system could provide estimation of an individuals age within +/-3 years in 42.4% of males and 49.4% of females, within +/-5 years in 61.8% of males and 63.3% of females. When the subjects were divided into two age groups and data were re-treated, the accuracy of age estimation was increased. Collectively, it was shown that our new system for scoring tooth wear is a reliable and accurate method for age estimation.

Metals in Particulate Pollutants Affect Peak Expiratory Flow of Schoolchildren

Background The contribution of the metal components of particulate pollutants to acute respiratory effects has not been adequately evaluated. Moreover, little is known about the effects of genetic polymorphisms of xenobiotic metabolism on pulmonary function. Objectives This study was conducted to assess lung function decrement associated with metal components in particulate pollutants and genetic polymorphisms of glutathione S-transferase M1 and T1. Methods We studied 43 schoolchildren who were in the 3rd to 6th grades. Each student measured peak expiratory flow rate three times a day for 42 days. Particulate air concentrations were monitored every day, and the concentrations of iron, manganese, lead, zinc, and aluminum in the particles were measured. Glutathione S-transferase M1 and T1 genetic polymorphisms were determined using DNA extracted from participant buccal washings. We used a mixed linear regression model to estimate the association between peak expiratory flow rate and particulate air pollutants. Results We found significant reduction in the peak expiratory flow rate after the children’s exposure to particulate pollutants. The effect was shown most significantly 1 day after exposure to the ambient particles. Manganese and lead in the particles also reduced the peak expiratory flow rate. Genetic polymorphisms of glutathione S-transferase M1 and T1 did not significantly affect peak expiratory flow rate. Conclusions This study demonstrated that particulate pollutants and metals such as manganese and lead in the particles are associated with a decrement of peak expiratory flow rate. These effects were robust even with consideration of genetic polymorphisms of glutathione S-transferase.

Urinary PAH Metabolites Influenced by Genetic Polymorphisms of GSTM1 in Male Hospital Incinerator Workers

Urinary PAH Metabolites Influenced by Genetic Polymorphisms of GSTM1 in male Hospital Incinerator Workers: Kyoung Ho Lee, et al. Department of Preventive Medicine, Seoul National University College of Medicine, Institute for Environmental Medicine, SNURC Korea—Hospital waste incinerator workers are exposed to various pyrolysis products including polycyclic aromatic hydrocarbons (PAHs). We evaluated their exposure by assessing urinary 1‐hydroxypyrene glucuronide (1‐OHPG), as an internal dose of PAH exposure. The potential effect of genetic polymorphisms of GSTM1/ T1 involved in PAH metabolisms was also investigated. Pre‐ and post‐shift samples were collected from 28 hospital incinerator workers. Urinary 1‐OHPG was assayed by synchronous fluorescence spectroscopy (SFS) after immunoaffinity purification with the monoclonal antibody 8E11. Genotypes of GSTM1/T1 were assessed by PCR‐based methods. Information on smoking habits and use of personal protective equipment were collected by means of a self‐administered questionnaire. The Mann‐Whitney test was used to compare group means of these biomarkers. Urinary 1‐OHPG levels were similar in pre‐ and post‐shift urine samples. The arithmetic mean concentrations of urinary 1‐OHPG were 0.16 ± 0.04 µmol/mol creatinine pre‐shift and 0.19 ± 0.09 µmol/mol creatinine post‐shift, but urinary 1‐OHPG levels were significantly higher in individuals with the GSTM1 null genotype than with the GSTM1 present genotype (p=0.05, by Mann‐Whitney test). Our results suggest that the urinary 1‐OHPG levels in hospital waste incinerator workers may be modified by the GSTM1 genotype, but these findings remain to be confirmed in future studies involving larger sample sizes.

Numerical simulation in converging channel flow of the fluid M1 using an integral constitutive equation

Abstract Numerical simulations have been undertaken for the flow of test fluid M1 passing through the converging channel system designed to measure the extensional viscosity of polymeric liquids. The constitutive equation is an integral-type K-BKZ model with three relaxation times. The simulations have been performed for the full range of experimental measurements in this system, where the extensional deformation is dominant and the deformation rates are very high. Stable solutions have been obtained for the whole range even though the apparent shear rates reach 1300s−1. Results concerning wall pressure difference between two pressure taps are compared with the experimental data measured from the pressure signals. The simulations are in good agreement with the experiments for the low range of flow rates at 21°C and for all flow rates at 30 and 40°C. The discrepancies at high flow rates for the lower temperature are apparently due to the appearance of a stationary bubble in the experiments that may have altered the pressure measurements. The pressure and stress distributions from the simulations show the flow characteristics of the converging channel system, which are difficult to verify by using experimental methods. The specially designed converging channel geometry makes the fluid M1 deform at a constant rate of extensional deformation near the centreline within the constant strainrate section but only at low flow rates, and its normal stresses increase exponentially and then slowly relax in the subsequent cylindrical section. The extensional viscosity of fluid M1 obtained by simulations has been compared with the value from the experimental results. A more appropriate method of measuring extensional viscosity is recommended from the stress analysis in the converging channel flow field.

Association by Spatial Interpolation between Ozone Levels and Lung Function of Residents at an Industrial Complex in South Korea.

Spatial interpolation is employed to improve exposure estimates and to assess adverse health effects associated with environmental risk factors. Since various studies have reported that high ozone (O3) concentrations can give rise to adverse effects on respiratory symptoms and lung function, we investigated the association between O3 levels and lung function using a variety of spatial interpolation techniques and evaluated how different methods for estimating exposure may influence health results for a cohort from an industrial complex (Gwangyang Bay) in South Korea in 2009. To estimate daily concentrations of O3 in each subject, four different methods were used, which include simple averaging, nearest neighbor, inverse distance weighting, and kriging. Also, to compare the association between O3 levels and lung function by age-groups, we explored ozone’s impacts on three age-related groups: children (9–14 years), adults (15–64 years), and the elderly (≥65 years). The overall change of effect size on lung function in each age group tended to show similar patterns for lag and methods for estimating exposure. A significant negative association was only observed between O3 levels and FVC and FEV1 for most of the lag and methods in children. The largest effect of O3 levels was found at the average for the lung function test day and last 2 days (0–2 days). In conclusions, the spatial interpolation methods may benefit in providing individual-level exposure with appropriate temporal resolution from ambient monitors. However, time-activity patterns of residents, monitoring site locations, methodological choices, and other factors should be considered to minimize exposure misclassification.

The compact multi-band internal chip antenna

This paper suggests a miniature internal chip antenna with quad band for operating at multi-band handset applications, including global system for mobile communication (GSM), digital communication system (DCS), personal communication system (PCS), and universal mobile telecommunication system (UMTS) band. The proposed antenna can be easily placed in practical handsets because of the small size of 28.3 times 5.1 times 3.2 mm3 . The electrical and structural characteristics of the proposed antenna make it attractive for use in mobile handset applications.

Indoor levels of volatile organic compounds and formaldehyde from emission sources at elderly care centers in Korea.

The objective of this study is to characterize indoor and outdoor levels of volatile organic compounds (VOCs) and formaldehyde (HCHO) and identify indoor emission sources in thirty elderly care centers (ECCs) located in the Seoul metropolitan city and Gyeonggi province in Korea. Air monitoring samples from indoor and outdoor environments were collected from January to December in 2007. Statistical analyses of indoor and outdoor VOCs and HCHO levels in three rooms (a bedroom, living, and dining rooms) of each ECC were performed, and these were compared to identify environmental factors associated with an increase of indoor pollution levels. Total volatile organic compounds (TVOC) levels were significantly (p<0.05) different between indoor (230.7±1.7 μg/m3) and outdoor (137.8±1.9 μg/m3) environments, with an I/O ratio of 1.67. The indoor HCHO level (20.1±1.6 μg/m3) was significantly (p<0.05) higher than the outdoor level (8.1±1.9 μg/m3), with an I/O ratio of 2.48. Indoor VOCs and HCHO levels in the bedrooms were significantly (p<0.05) higher than those in the living and dining rooms. Furthermore, indoor levels of VOCs and HCHO at ECCs were significantly (p<0.05) different depending on environmental factors such as the use of carpet, paint, and wooden furniture. In multiple regression analysis, indoor VOCs and HCHO levels at ECCs were significantly (p<0.05) correlated with two micro-environmental factors: the use of carpet and paint. This study confirmed that indoor VOCs and HCHO levels were significantly higher than those in outdoor environments. These air pollutants were mainly emitted from indoor sources, such as carpet, paint, and construction materials at the ECCs in Korea.

Effects of Environmental Air Pollution on Pulmonary Function Level of Residents in Korean Industrial Complexes

This study aims to identify environmental air pollution adversely affecting pulmonary function among a community-based general population living in Korean industrial complexes. A total of 1963 residents participated in a pulmonary function test (PFT). The sample population consisted of an exposed group (n = 1487) living within a radius of 5 km of industrial complexes and a control group (n = 476) living over a radius of 10 km from the industrial complexes in Gwangyang and Yeosu cities. PFT results were calculated for each resident of the study population. On-site questionnaire surveys with face-to-face interviews were also conducted to collect more detailed information on personal lifestyles, medical history, exposure to air pollution, and respiratory disease and related symptoms. A total of 486 measured samples were collected by eight automated air-monitoring stations installed in four counties of Gwangyang and four counties of Yeosu in South Korea from January 2006 to February 2007. Mean levels of SO2 (0.012 ppm), CO (0.648 ppm), NO2 (0.02 ppm), O3 (0.034 ppm), and PM10 (43.07 μg/m3), collected within a radius of 5 km, were significantly higher than those collected over a radius of 10 km from Gwangyang and Yeosu industrial complexes. Prevalence odds ratio (OR) of abnormal pulmonary function in the exposed group of residents (<5 km) was elevated at 1.24 (95% CI 0.71–1.96), but not statistically significant (p > 0.05). In multiple linear regression analysis, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) levels significantly declined as SO2, CO, and O3 levels increased when adjusting for age, sex, body mass index (BMI), alcohol, smoking, secondhand smoke, and respiratory disease and related symptoms (n = 1963) (p < 0.05). These results suggest that exposure to air pollution affects pulmonary function levels of residents living in Korean industrial complexes.