The Cytogenetic Effects of Benzene and Toluene on Bone Marrow Cells in Rats

Roh, Jaehoon,Moon, Young Hahn,Kim, Kir-Young Yonsei University, College of Medicine 1987 Yonsei medical journal Vol.28 No.4

Effects Quantification of Symptoms in Upper Extremities Among Hospital Workers Using Video Display Terminals

Jaehoon Roh,Hyoung-Ryoul Kim(김형렬),Jong-uk Won,Jae-suk Song,Chi-Nyon Kim,Hyun-Soo Kim 대한산업의학회 2003 대한직업환경의학회 학술대회 논문집 Vol.30 No.-

인천지역 제조업 종사 근로자들의 진폐증

노재훈,안연순,김규상,정호근,황일순 大韓産業醫學會 1997 대한직업환경의학회지 Vol.9 No.4

Most of pneumoconiosis found in Korea can be categorized in coal worker's pneumoconiosis. However, in recent years, pneumoconiosis has been frequently found in the workers of manufacturing factories. Accordingly, this study was carried out to invstigate relationship of dust exposure history and development and progress of pneumoconiosis. Chest radiographs, history of dust exposure, and other data of 144 workers, who were diagnosed as suspected pneumoconiosis (0/1) or pneumoconiosis in special health examination center in Incheon from 1986 to 1996, were reviewed. The results were as follows; 1. According to the type of main exposure, most common type of exposure was foundry dust(93workers, 64.6%), followed by welding fume (16workers, 11.1%), talc dust, lime dust and etc. 2. Among 144 workers, the history of dust exposure was investigated in 86 workers. Mean ages of 86 workers at the present study, initial exposure to the dusts, and at the time of initial diagnosis as having pneumoconiosis were 52.1, 29.1 and 46.5 years, respectively. The mean duration of exposure was 17.3 years. 3. Comparing the type of main exposure with dust exposure history, initially exposed age of welders, foundry workers, workers exposed to coal dust and other dusts were 24.6, 30.7, 28.0 and 28.5 years, respectively. Ages at the time of diagnosis as having pneumoconiosis of welders, foundry workers, coal dust and other dusts were 41.3, 49.3, 46.4 and 44.1 years, respectively. The duration of exposure to main dust of welders, foundry workers, workers exposed to coal dust and other dusts were 16.8, 18.2, 13.3 and 11.6 years, respectively. Therefore initially exposed age was significant difference between the welders and the foundry workers(p<.05). Age which was diagnosed pneumoconiosis was significant difference between the welders, workers exposed to other dusts and the foundry workers (p<.01). And exposure duration of main dust was significant difference between the workers exposed to other dusts and foundry workers(p<.01) 4. Initially diagnosed X-ray category of the workers were category were category 0/1(76workers, 52.8%), 1/0(35workers, 24.3%). Therefore, workers' pneumoconiosis of manufacturing factories was mild, relatively. And there was no significant difference between initially diagnosed X-ray category of the workers and dust exposure history. 5. Among 97 workers, who could follow up more than 1 year, 60 workers (61.9%) were not changed, 24 workers (24.7%) were progressed, 13 workers (13.4%) were improved in their initially diagnosed X-ray category. Among 11 welders, initially diagnosed X-ray category of 5 welders (45.5%) were improved and of only 1 welder was progressed. But, among 19 workers exposed to other dusts, 10 (52.6%) workers were progressed and none of them were improved. 6. Among 53 workers, who were Initially diagnosed X-ray category was 0/1, 12 workers(22.6%) were progressed and 5 workers (9.4%) were improved in their initially diagnosed X-ray category. And among 40 workers, who were initially diagnosed X-ray category was 1, 12 workers (30.0%) were progressed and 7 workers (17.5%) were improved. Above results suggest that not a few workers of manufacturing factories have pneumoconiosis and their pneumoconiosis is progressed. Therefore, we have to prepare management plan and to study epidemiologic findings of pneumoconiosis with workers of manufacturing factories.

벤지딘 염산염 및 염료 제조 근로자들의 피부 노출 평가

노재훈,김치년,송재석,염혜경,원종욱 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.1

This study is performed to evaluate usefulness of dermal measurement of benzidine and benzidine based dye as one of the occupational exposure assessment method for these compounds. We selected one benzidine manufacturing factory and one dye manufacturing factory in Inchen area. Eleven workers were for benzidine manufacturing factory and twenty four for dye. We analyzed relationships among air level, amount on skin and concentration of urinary metabolites for these compounds. Airborne levels of benzidine and dye were measured by NIOSH 5509, 5013 methods. Amount of these compounds on skin was measured with skin wipe method. Concentration of benzidine metabolites in urine was measured by High Performance Liquid Chromatography after alkaline hydrolysis. The amount of benzidine on hand skin was 25.05(-233.2) ng/㎠, and the amount of the neck was 2.01(-11.9) ng/㎠ in the benzidine dihydrochloride manufacturing factory. The amount of benzidine on hand and neck skin has positive correlation with concentration of urinary monoacetyl benzidin(r=0.644, p<0.05). The amount of benzidine based dye on hand skin was 55.75(-457.7) ng/㎠, and the amount of the neck skin was 18(-284.7) ng/㎠ in benzidine based dye manufacturing factory. The amount of dye on hand and neck skin has positive correlation with concentration of urinary benzidine for dye workers(r=0.467, p<0.05). When assessing the exposure of workers who deal with benzidine, the amount of benzidine on skin should be measured for an accurate exposure assessment.

CRISPR-Cas9-mediated generation of obese and diabetic mouse models

Roh, Jae-il,Lee, Junghoon,Park, Seong Uk,Kang, Young-Shin,Lee, Jaehoon,Oh, Ah-Reum,Choi, Dong Joon,Cha, Ji-Young,Lee, Han-Woong KINOKUNIYA CO LTD 2018 EXPERIMENTAL ANIMALS Vol.67 No.2

<P>Mouse models of obesity (<I>ob</I>/<I>ob</I>) and diabetes (<I>db</I>/<I>db</I>) in which the leptin (<I>Lep</I>) and leptin receptor (<I>Lepr</I>) genes have been mutated, respectively, have contributed to a better understanding of human obesity and type 2 diabetes and to the prevention, diagnosis, and treatment of these metabolic diseases. In this study, we report the first CRISPR-Cas9-induced <I>Lep</I> and <I>Lepr</I> knockout (KO) mouse models by co-microinjection of Cas9 mRNA and sgRNAs that specifically targeted <I>Lep</I> or <I>Lepr</I> in C57BL/6J embryos. Our newly established <I>Lep</I> and <I>Lepr</I> KO mouse models showed phenotypic disorders nearly identical to those found in <I>ob</I>/<I>ob</I> and <I>db</I>/<I>db</I> mice, such as an increase in body weight, hyperglycemia, and hepatic steatosis. Thus, Cas9-generated <I>Lep</I> and <I>Lepr</I> KO mouse lines will be easier for genotyping, to maintain the lines, and to use for future obesity and diabetes research.</P>

Influence of External Pressure on the Performance of Quantum Dot Solar Cells

Kim, Jaehoon,Jeong, Byeong Guk,Roh, Heebum,Song, Jiyun,Park, Myeongjin,Lee, Doh C.,Bae, Wan Ki,Lee, Changhee American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.36

<P>We report the influence of post-treatment via the external pressure on the device performance of quantum dot (QD) solar cells. The structural: analysis together with optical and electrical characterization on QD solids reveal that the external,pressure compacts QD active layers by removing the mesoscopic voids and enhances the charge carrier transport-along QD solids leading to significant increase in J(SC) of QD solar cells. Increasing the external pressure, by contrast, accompanies reduction in FE and V-OC, yielding the trade-off relationship among J(SC), and FF and V-OC in PCE of devices. Optimization at the external pressure in the present study at 1.4-1.6 MPa enables us to achieve over 10% increase in PCE of QD solar cells. The approach and results show that the control over the organization of QDs is the key for the-charge transport properties in ensemble and also offer simple yet effective; mean to enhance the electrical performance of transistors and solar cells using QDs.</P>

Transgenic overexpression of p23 induces spontaneous hydronephrosis in mice

Lee, Jaehoon,Kim, Hye Jin,Moon, Jung Ah,Sung, Young Hoon,Baek, In‐,Jeoung,Roh, Jae‐,il,Ha, Na Young,Kim, Seung‐,Yeon,Bahk, Young Yil,Lee, Jong Eun,Yoo, Tae Hyun,Lee, Han‐,Woong Blackwell Publishing Ltd 2011 International journal of experimental pathology Vol.92 No.4

<P><B>Summary</B></P><P>p23 is a cochaperone of heat shock protein 90 and also interacts functionally with numerous steroid receptors and kinases. However, the <I>in vivo</I> roles of p23 remain unclear. To explore its <I>in vivo</I> function, we generated the transgenic (TG) mice ubiquitously overexpressing p23. The p23 TG mice spontaneously developed kidney abnormalities closely resembling human hydronephrosis. Consistently, kidney functions deteriorate significantly in the p23 TG mice compared to their wild‐type (WT) littermates. Furthermore, the expression of target genes for aryl hydrocarbon receptor (AhR), such as cytochrome P450, family 1, subfamily A, polypeptide 1 (Cyp1A1) and cytochrome P450, family 1, subfamily B, polypeptide 1 (Cyp1B1), were induced in the kidneys of the p23 TG mice. These results indicate that the overexpression of p23 contributes to the development of hydronephrosis through the upregulation of the AhR pathway <I>in vivo.</I></P>

Exendin-4 Improves Nonalcoholic Fatty Liver Disease by Regulating Glucose Transporter 4 Expression in ob/ob Mice

Seok Kim,Jaehoon Jung,Hwajin Kim,Rok Won Heo,Chin-ok Yi,Jung Eun Lee,Byeong Tak Jeon,Won-Ho Kim,Jong Ryeal Hahm,Gu Seob Roh 대한생리학회-대한약리학회 2014 The Korean Journal of Physiology & Pharmacology Vol.18 No.4

Exendin-4 (Ex-4), a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been known to reverse hepatic steatosis in ob/ob mice. Although many studies have evaluated molecular targets of Ex-4, its mechanism of action on hepatic steatosis and fibrosis has not fully been determined. In the liver, glucose transporter 4 (GLUT4) is mainly expressed in hepatocytes, endothelial cells and hepatic stellate cells (HSCs). In the present study, the effects of Ex-4 on GLUT4 expression were determined in the liver of ob/ob mice. Ob/ob mice were treated with Ex-4 for 10 weeks. Serum metabolic parameters, hepatic triglyceride levels, and liver tissues were evaluated for hepatic steatosis. The weights of the whole body and liver in ob/ob mice were reduced by long-term Ex-4 treatment. Serum metabolic parameters, hepatic steatosis, and hepatic fibrosis in ob/ob mice were reduced by Ex-4. Particularly, Ex-4 improved hepatic steatosis by enhancing GLUT4 via GLP-1R activation in ob/ob mice. Ex-4 treatment also inhibited hepatic fibrosis by decreasing expression of connective tissue growth factor in HSCs of ob/ob mice. Our data suggest that GLP-1 agonists exert a protective effect on hepatic steatosis and fibrosis in obesity and type 2 diabetes.

Molecular biomarkers of occupational lung cancer

Talaska, Glenn,Roh, Jaehoon,Zhou, Qing Yonsei University, College of Medicine 1996 Yonsei medical journal Vol.37 No.1

Comparison of the relative performance efficiencies of melt-blown and glass fiber filter media for managing fine particles

Hwang, Sungho,Roh, Jaehoon,Park, Wha Me Informa UK (TaylorFrancis) 2018 AEROSOL SCIENCE AND TECHNOLOGY Vol.52 No.4

<P>The purpose of this study was to compare the performance efficiency of melt-blown and currently used glass fiber filter media under the same environmental conditions. To evaluate filter efficiency, filter class was determined according to ISO and European standards (EN 1822-1:2009) using an automated filter tester (0.3m size), taking into account particle filtration, fractional efficiency for negative pressure devices, and consumption of electrical power. The average fractional efficiency, quality factor (QF), fractional efficiency by dust loading amount, pressure by dust loading amount, and QF by dust loading amount were higher in the case of melt-blown media than in the case of glass fiber filters. The fractional efficiency of hydrocharged melt-blown filters was higher than that of uncharged media. Based on performance efficiency, melt-blown filters are more effective high efficiency particulate air filters than glass fiber media.Copyright (c) 2018 American Association for Aerosol Research</P>