Occupational Lung Disease Institute

Korea, South Korea

Occupational Lung Disease Institute

Korea, South Korea
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Sung M.-S.,Chonnam National University | Yoon J.-H.,Occupational Lung Disease Institute | Park S.-W.,Chonnam National University
Journal of Glaucoma | Year: 2014

Purpose: To evaluate the diagnostic validity of macular ganglion cell-inner plexiform layer (mGCIPL) thickness deviation map algorithm using Cirrus high definition-optical coherence tomography to discriminate between normal controls and patients with preperimetric or early glaucoma.Patients and Methods: Seventy-two normal controls, 37 patients with preperimetric glaucoma and 70 patients with early glaucoma were enrolled. mGCIPL thickness and peripapillary retinal nerve fiber layer (pRNFL) thickness were measured by Cirrus high definition-optical coherence tomography. Areas showing abnormal color coding were obtained by customized Image J software calculating the number of abnormal superpixels at 1% and 5% level in each deviation map of measurements (GCIPL-DM1, GCIPLDM5, RNFL-DM1, RNFL-DM5). The area under the receiver operating characteristic curve (AROC) of each parameter was calculated to provide diagnostic ability between normal controls and patients with preperimetric or early glaucoma.Results: AROCs of the deviation map algorithms were higher than those of other parameters. Parameter with the best AROC was the GCIPL-DM5 (0.920 and 0.968) in both preperimetric and early glaucoma. The sensitivities of the GCIPL-DM5 at 80% and 95% specificities were 92% and 68% in preperimetric glaucoma and 98% and 90% in early glaucoma, respectively. Pairwise comparisons between AROCs of parameters from deviation map algorithms did not show statistically significant differences.Conclusions: mGCIPL thickness deviation map showed good diagnostic ability in detecting preperimetric and early glaucoma, and it was comparable with pRNFL thickness deviation map. Our findings suggest that it can be an important parameter in detecting subtle glaucomatous structural change. Copyright © 2013 by Lippincott Williams & Wilkins.


Lee K.-H.,Seoul National University | Jung H.-J.,Catholic Kwandong University | Park D.-U.,Korea University | Ryu S.-H.,Korea University | And 5 more authors.
PLoS ONE | Year: 2015

Objective: The purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM. Methods: A total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014. Respirable EC/OC samples were quantified using the thermal optical transmittance method. BC and PM 2.5 were measured using real-time monitors, an aethalometer and a laser photometer. All results were statistically analyzed for occupational and environmental variables to identify the exposure determinants of DPM. Results: The geometric mean of EC, OC, TC, BC and PM 2.5 concentrations were 4.8, 39.6, 44.8, 9.1 and 62.0 μg/m3, respectively. EC concentrations were significantly correlated with the concentrations of OC, TC and BC, but not with those of PM 2.5. The exposures of the MHW collectors to EC, OC, and TC were higher than those of the drivers (p<0.05). Workers of trucks meeting Euro 3 emission standard had higher exposures to EC, OC, TC and PM 2.5 than those working on Euro 4 trucks (p<0.05). Multiple regression analysis revealed that the job task, European engine emission standard, and average driving speed were the most influential factors in determining worker exposure. Conclusions: We assessed MHW workers' exposure to DPM using parallel sampling of five possible indicators. Of these five indicators, EC was shown to be the most useful indicator of DPM exposure for MHW workers, and the job task, European emission standard, and average driving speed were the main determinants of EC exposure. Copyright: © 2015 Lee et al.


PubMed | Catholic Kwandong University, Occupational Safety & Health Research Institute, Seoul National University, Keimyung University and 3 more.
Type: Journal Article | Journal: PloS one | Year: 2015

The purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM.A total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014. Respirable EC/OC samples were quantified using the thermal optical transmittance method. BC and PM 2.5 were measured using real-time monitors, an aethalometer and a laser photometer. All results were statistically analyzed for occupational and environmental variables to identify the exposure determinants of DPM.The geometric mean of EC, OC, TC, BC and PM 2.5 concentrations were 4.8, 39.6, 44.8, 9.1 and 62.0 g/m3, respectively. EC concentrations were significantly correlated with the concentrations of OC, TC and BC, but not with those of PM 2.5. The exposures of the MHW collectors to EC, OC, and TC were higher than those of the drivers (p<0.05). Workers of trucks meeting Euro 3 emission standard had higher exposures to EC, OC, TC and PM 2.5 than those working on Euro 4 trucks (p<0.05). Multiple regression analysis revealed that the job task, European engine emission standard, and average driving speed were the most influential factors in determining worker exposure.We assessed MHW workers exposure to DPM using parallel sampling of five possible indicators. Of these five indicators, EC was shown to be the most useful indicator of DPM exposure for MHW workers, and the job task, European emission standard, and average driving speed were the main determinants of EC exposure.


Yoon J.-H.,Occupational Lung Disease Institute | Kim B.,Occupational Lung Disease Institute | Choi B.-S.,Occupational Lung Disease Institute | Park S.Y.,Occupational Lung Disease Institute | And 3 more authors.
Safety and Health at Work | Year: 2013

Here, we present a case of lung cancer in a 48-year-old male horse trainer. To the best of our knowledge, this is the first such case report to include an exposure assessment of respirable crystalline silica (RCS) as a quartz. The trainer had no family history of lung cancer. Although he had a 15 pack/year cigarette-smoking history, he had stopped smoking 12 years prior to his diagnosis. For the past 23 years, he had performed longeing, and trained 7-12 horses per day on longeing arena surfaces covered by recycled sands, the same surfaces used in race tracks. We investigated his workplace RCS exposure, and found it to be the likely cause of his lung cancer. The 8-hour time weight average range of RCS was 0.020 to 0.086 mg/m3 in the longeing arena. Horse trainers are exposed to RCS from the sand in longeing arenas, and the exposure level is high enough to have epidemiological ramifications for the occupational risk of lung cancer. Copyright © 2013 by Safety and Health at Work (SH@W).


Yoon J.-H.,Occupational Lung Disease Institute | Yoon J.-H.,Yonsei University | Junger W.,State University of Rio de Janeiro | Kim B.-W.,Occupational Lung Disease Institute | And 2 more authors.
Safety and Health at Work | Year: 2012

Previous studies on the vast increase in suicide mortality in Southeast Asia have indicated that suicide rates increase in parallel with a rise in unemployment or during periods of economic recession. This paper examines the effects of economic recession on suicidal rates amongst agriculture, fisheries, and forestry workers in Korea. Monthly time-series gross domestic product (GDP) data were linked with suicidal rates gathered from the cause of death records between 1993-2008. Data were analyzed using generalized additive models to analyze trends, while a polynomial lag model was used to assess the unconstrained time lag effects of changes in GDP on suicidal rate. We found that there were significant inverse correlations between changes in GDP and suicide for a time lag of one to four months after the occurrence of economic event. Furthermore, it was evident that the overall relative risks of suicide were high enough to bring about social concern. Copyright © 2012 by Safety and Health at Work (SH@W).


Oh S.,Ministry of Employment and Labor | Oh S.,Catholic University of Korea | Kim B.,Occupational Lung Disease Institute | Kim H.,Catholic University of Korea
Industrial Health | Year: 2014

Silica nanoparticles (SNPs) are widely used all around the world and it is necessary to evaluate appropriate risk management measures. An initial step in this process is to assess worker exposures in their current situation. The objective of this study was to compare concentrations and morphologic characteristics of fumed (FS) and sol-gel silica nanoparticles (SS) in two manufacturing facilities. The number concentration (NC) and particle size were measured by a real-time instrument. Airborne nanoparticles were subsequently analyzed using a TEM/EDS. SNPs were discharged into the air only during the packing process, which was the last manufacturing step in both the manufacturing facilities studied. In the FS packing process, the geometric mean (GM) NC in the personal samples was 57,000 particles/cm3. The geometric mean diameter (GMD) measured by the SMPS was 64 nm. Due to the high-temperature formation process, the particles exhibited a sintering coagulation. In the SS packing process that includes a manual jet mill operation, the GM NC was calculated to be 72,000 particles/cm3with an assumption of 1,000,000 particles/cm3when the upper limit is exceeded (5% of total measure). The particles from SS process had a sphericalshaped morphology with GMD measured by SMPS of 94 nm. © 2014 National Institute of Occupational Safety and Health.


Kim B.,Occupational Lung Disease Institute | Kim H.,Catholic University of Korea | Yu I.J.,Hoseo University
Industrial Health | Year: 2014

Nanosilica is one of the most widely used nanomaterials across the world. However, their assessment data on the occupational exposure to nanoparticles is insufficient. The present study performed an exposure monitoring in workplace environments where synthetic powders are prepared using fumed nanosilica. Furthermore, after it was observed during exposure monitoring that nanoparticles were emitted through leakage in a vacuum cleaner (even with a HEPA-flter installed in it), the properties of the leaked nanoparticles were also investigated. Workers were exposed to high-concentration nanosilica emitted into the air while pouring it into a container or transferring the container. The use of a vacuum cleaner with a leak (caused by an inadequate sealing) was found to be the origin of nanosilica dispersion in the indoor air. While the particle size of the nanosilica that emitted into the air (during the handling of nanosilica by a worker) was mostly over 100 nm or several microns (μm) due to the coagulation of particles, the size of nanosilica that leaked out of vacuum cleaner was almost similar to the primary size (mode diameter 11.5 nm). Analysis of area samples resulted in 20% (60% in terms of peak concentration) less than the analysis of the personals sample. © 2014 National Institute of Occupational Safety and Health.


PubMed | Yonsei University, Affiliated Hospital, M&D Inc. and Occupational Lung Disease Institute
Type: Journal Article | Journal: Journal of microbiology (Seoul, Korea) | Year: 2015

Drug resistance in Mycobacterium leprae is a significant problem in countries where leprosy is endemic. A sensitive, specific, and high-throughput reverse blot hybridization assay (REBA) for the detection of genotypic resistance to rifampicin (RIF) was designed and evaluated. It has been shown that resistance to RIF in M. leprae involves mutations in the rpoB gene encoding the -subunit of the RNA polymerase. The PCR-REBA simultaneously detects both 6 wild-type regions and 5 different mutations (507 AGC, 513 GTG, 516 TAT, 531 ATG, and 531 TTC) including the most prevalent mutations at positions 507 and 531. Thirty-one clinical isolates provided by Korea Institute of Hansen-s Disease were analyzed by PCR-REBA with RIF resistance of rpoB gene. As a result, missense mutations at codons 507 AGC and 531 ATG with 2-nucleotide substitutions were found in one sample, and a missense mutation at codon 516 TAT and WT6 (deletion of 530-534) was found in another sample. These cases were confirmed by DNA sequence analysis. This rapid, simple, and highly sensitive assay provides a practical alternative to sequencing for genotypic evaluation of RIF resistance in M. leprae.


PubMed | Occupational Lung Disease Institute
Type: Journal Article | Journal: Industrial health | Year: 2014

Nanosilica is one of the most widely used nanomaterials across the world. However, their assessment data on the occupational exposure to nanoparticles is insufficient. The present study performed an exposure monitoring in workplace environments where synthetic powders are prepared using fumed nanosilica. Furthermore, after it was observed during exposure monitoring that nanoparticles were emitted through leakage in a vacuum cleaner (even with a HEPA-filter installed in it), the properties of the leaked nanoparticles were also investigated. Workers were exposed to high-concentration nanosilica emitted into the air while pouring it into a container or transferring the container. The use of a vacuum cleaner with a leak (caused by an inadequate sealing) was found to be the origin of nanosilica dispersion in the indoor air. While the particle size of the nanosilica that emitted into the air (during the handling of nanosilica by a worker) was mostly over 100nm or several microns (m) due to the coagulation of particles, the size of nanosilica that leaked out of vacuum cleaner was almost similar to the primary size (mode diameter 11.5nm). Analysis of area samples resulted in 20% (60% in terms of peak concentration) less than the analysis of the personals sample.


PubMed | Occupational Lung Disease Institute
Type: Journal Article | Journal: Safety and health at work | Year: 2013

Here, we present a case of lung cancer in a 48-year-old male horse trainer. To the best of our knowledge, this is the first such case report to include an exposure assessment of respirable crystalline silica (RCS) as a quartz. The trainer had no family history of lung cancer. Although he had a 15 pack/year cigarette-smoking history, he had stopped smoking 12 years prior to his diagnosis. For the past 23 years, he had performed longeing, and trained 7-12 horses per day on longeing arena surfaces covered by recycled sands, the same surfaces used in race tracks. We investigated his workplace RCS exposure, and found it to be the likely cause of his lung cancer. The 8-hour time weight average range of RCS was 0.020 to 0.086 mg/m(3) in the longeing arena. Horse trainers are exposed to RCS from the sand in longeing arenas, and the exposure level is high enough to have epidemiological ramifications for the occupational risk of lung cancer.

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