• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.2
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• pp.124-134
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• 2005

To investigate the exposure effect of polynuclear aromatic hydrocarbons (PAHs), we measured airborne total PAHs as an external dose, urinary 1-hydroxypyrene (1-OHP) as an internal dose of PAHs exposure, and analyzed the relationship between urinary 1-OHP concentration and PAHs exposure. The study population contained 44 workers in steel-pipe coating and paint manufacture industries. The airborne PAHs was obtained during survey day, and urine were sampled at the end of shift. Personal information on age, body weight, height, eniployment duration, smoking habit, and alcohol consumption was obtained by a structured questionnaire. Airborne PAHs were analyzed by the gas chromatograph with mass selective detector. Urinary 1-OHP levels were analyzed by the high performance liquid chromatograph with ultraviolet wavelength detector. For statistical estimation, t-test, ${\chi}^2$-test, analysis of variance, correlation analysis, arid regression analysis were executed by SPSS/PC (Windows version 10). The mean of environmental total PAHs was $87.8{\pm}7.81{\mu}g/m^3$. The mean concentration ($526.5{\pm}2.85{\mu}g/m^3$) of workers in steel-pipe coating industries using coal tar enamel was the higher than that ($17.5{\pm}3.36{\mu}g/m^3$) of workers in paint manufacture industries using coal tar paint. The mean of urinary 1-OHP concentration ($51.63{\pm}3.144{\mu}\;mol/mol$ creatinine) of workers in steel-pipe coating industries was the higher than that ($2.33{\pm}4.709{\mu}\;mol/mol$ creatinine) of workers in paint manufacture industries. The mean of urinary 1-OHP concentration of smokers was the higher than that of non-smokers. There was significant correlation between the urinary concentration of 1-OHP and the environmental concentration of PAHs (r=O.S48, p<0.001), pyrene(r=0.859, p<0.001), and urinary cotinine (r=0.324, p<0.05). The regression equation between the urinary concentration of 1-OHP in ${\mu}g/g$ creatinine($C_{1-OHP}$) and airborne concentration of PAHs (or pyrene) in ${\mu}g/m^3$ ($C_{PAHs}$ or Cpyrene) is: Log ($C_{1-OHP}$)=-0.650+0.889×Log($C_{PAHs}$), where $R^2=0.694$ and n=38 for p<0.001.Log ($C_{1-OHP}$)=1.087+0.707${\times}$Log(Cpyrene), where $R^2=0.713$ and n=38 for p<0.001. From the results of stepwise multiple regression analysis about 1-OHP, significant independents were total PAHs and urinary cotinine (adjusted $R^2=0.743$, p<0.001). In this study, there were significant correlation between the urinary concentration of 1-OHP and the airborne concentration of PAHs. The urinary 1-OHP was effective index as a biomarker of airborne PAHs in workplace. But it was influenced by non-occupational PAHs source, smoking.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.224-239
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• 1994

In this study we examined several subjective symptoms in an exposed group and an unexposed group to perchloroethylene. The exposed group consists to 30 workers employed in 23 dry-cleaning establishments located in Chung Cheung Do, whereas the unexposed group consists of 42 officers employed in a certain university. This study was conducted from October, 1993 to March, 1994. Also we investigated personal exposure levels and area concentration of PCE, and performed hematological and biochemical examination in blood and urine samples from the exposed group. The results are : 1. The exposed group highly complains several subjective symptoms, particularly in neuropsychiatry, eye, respiratory system and digestive system, compared with the unexposed group. But complaint rates in the exposed group are not related with PCE exposure levels. 2. PCE exposure levels for all dry-cleaning establishment varied widely, from 0.18 to 37.58ppm. The mean exposure level for centers of chain was 16.85ppm, and for local laundries was 8.83ppm, while for self-service establishment it was 3.07ppm. Eighty three percent of the workers were exposed less than the half-level(25.0ppm) of the Korea 50.0ppm standard for eight-hour PCE exposure. Seventeen percent of them exceeded the half-level of the Korea TLV. 3. Statistical correlation exists between the work load(number of operation cycles of equipment and the mass of processed textiles) and the personal exposure levels to be observed. 4. In hematological examination the values of WBC, RBC, Hgb, Hct, MCV, MCH, MCHC and PLT in the exposed group were within normal ranges. In biochemical examination(GOT, GPT, ALP, U-A and LDH) most of the items were within normal ranges. From this surveys conducted on 23 dry-cleaning establishments, the complaint rates of the exposed group to PCE in several subjective symptoms were higher than those of the unexposed group, and PCE exposure levels in all dry-cleaning establishment were below the Koera standard 50.0ppm. In hematological and biochemical examination the significant abnormalities by occupational exposure to PCE were not observed. However, the workers employed in dry-cleaning establishments are always faced with risk, becauses they are also exposed to several organic solvents used to remove stains. Therefore, various measures to improve occupational environment in dry-cleaning establishment should be considered.

• The Korean Society of Law and Medicine
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• v.19 no.1
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• pp.113-142
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• 2018

In recent years, there have been opinions in which physicians are liable to the revocation of their medical license if they are sentenced to above a certain level for criminal charges regardless of the types of offenses. Accordingly, a revised bill of law was submitted in the National Assembly, and related discussions are thus expected to commence. Considering the morality and ethics or the level of the rule of law that the general public expects of physicians, as well as the license revocation system in other professional sectors, it is assessed that medical license revocation due to criminal convictions of physicians is appropriate to some degree. However, if a poorly devised system is established based on unrefined inferences or emotional judgements, unexpected side-effects are likely to arise. With regard to serious criminal acts that society generally perceives as unacceptable, it can be assessed that the revocation of physicians' licenses would appropriately protect the general public from threats. However, given the life-saving characteristics of high-risk medical practices, higher malpractice exposures, and social values, it is difficult to assess charges of professional negligence resulting in death(or in injury) and minor offences in the same manner as anti-social criminal offences are handled. Physicians need to be treated the same as any other professions. At the same time, they are engaged in administering medical treatment to patients in the face of great risks as professionals. Under the circumstances, a discussion on the introduction of a more specific and empirical system is needed by considering the intrinsic characteristics of medical treatment and the need for an equitable health and medical policy. Accordingly, based on the above judgment and perception, this study explores the code of ethics for physicians and medical license revocation related to criminal offences at home and abroad, and examines various legislative alternatives appropriate for the Republic of Korea. In doing so, the purpose of the study is to contribute to the development of a reasonable system for handling criminal offences by physicians.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.47-52
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• 2018

Brain perfusion CT scanning is often employed usefully in clinical conditions as it accurately and promptly provides information about the perfusion state of patients having acute ischemic stroke with a lot of time constraints and allows them to receive proper treatment. Despite those strengths of it, it also has a serious weakness that Lens may be exposed to a lot of dose of radiation in it. In this study, as a way to reduce the dose of radiation to Lens in brain perfusion CT scanning, this researcher conducted an experiment with Bismuth shielding and change of patients' position. TLD (TLD-100) was placed on both lens using the phantom (PBU-50), and then, in total 4 positions, parallel to IOML, parallel to IOML (Bismuth shielding), parallel to SOML, and parallel to SOML (Bismuth shielding), brain perfusion scanning was done 5 times for each position, and dose to Lens were measured. Also, to examine how the picture quality changed in different positions, 4 areas of interest were designated in 4 spots, and then, CT number and noise changes were measured and compared. According to the results of conducting one-way ANOVA on the doses measured, as the significance probability was found to be 0.000, so there was difference found in the doses of radiation to crystalline lenses. According to the results of Duncan's post-hoc test, with the scanning of being parallel to IOML as the reference, the reduction of 89.16% and 89.66% was observed in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding) respectively, so the doses to Lens reduced significantly. Next, in the scanning of being parallel to IOML (Bismuth shielding), the reduction of 37.12% was found. According to the results, reduction in the doses of radiation was found the most significantly both in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding). With the limit of the equivalent dose to Lens as the reference, this researcher conducted comparison with the dose to occupational exposure and dose to Public exposure in the scanning of being parallel to IOML and found 39.47% and 394.73% respectively; however in the scanning of being parallel to SOML (Bismuth shielding), considerable reduction was found as 4.08% and 40.8% respectively. According to the results of evaluation on picture quality, every image was found to meet the evaluative standards of phantom scanning in terms of the measurement of CT numbers and noise. In conclusion, it would be the most useful way to reduce the dose of radiation to Lens to use shields in brain perfusion CT scanning and adjust patients' position so that their lens will not be in the field of radiation.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.23-30
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• 2018

To evaluate the effect of patient size on effective dose and image quality for Digital Chest Tomosynthesis(DTS) using additional 0.3 mm copper filtration. Eighty artificial nodules were placed in the thorax phantom("Lungman," Kyoto Kagaku, Japan), and Digital Chest Tomosynthesis(DTS) images of the phantom were acquired both with and without added 0.3 mm Cu filtration. To simulate patients of three sizes: small, average size and oversize, one or two 20-mm-thick layer of PMMA(polymethyl methacrylatek) blocks were placed on the phantom. The Effective dose was calculated using Monte Carlo simulations. Two evaluations of image quality methods have been employed. Three readers counted the number of nodules detected in the lung, and the measured contrast-to-noise ratios(CNRs) were used. Data were analyzed statistically. The ED reduced $26{\mu}Sv$ in a phantom, $33{\mu}Sv$ in one 20-mm-thick layer of PMMA block placed on the phantom, and $48{\mu}Sv$ in two 20-mm-thick layer of PMMA blocks placed on the phantom. The Effective dose(ED) differences between DTS with and without filtration were significant(p<0.05). In particular, when we used two 20-mm-thick layer of PMMA blocks placed on the phantom, the ED was significantly reduced by 36% compared with those without additional filtration. Nodule detection sensitivities were not different between with and without added filtration. Differences of CNRs were statistically insignificant(p>0.05). Use of additional filtration allows a considerable dose reduction during Digital Chest Tomosynthesis(DTS) without loss of image quality. In particular, additional filtration showed outstanding result for effective dose reduction on two 20-mm-thick layer of PMMA blocks placed on the phantom. It applies to overweight patients.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.547-553
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• 2017

In the current medical field, lead is widely used as a radiation shield. However, the lead weight is very heavy, so wearing protective clothing such as apron is difficult to wear for long periods of time and there is a problem with the danger of lethal toxicity in humans. Recently, many studies have been conducted to develop substitute materials of lead to resolve these problems. As a substitute materials for lead, barium(Ba) and iodine(I) have excellent shielding ability. But, It has characteristics emitting characteristic X-rays from the energy area near 30 keV. For patients or radiation workers, shielding materials is often made into contact with the human body. Therefore, the characteristic X-rays generated by the shielding material are directly exposured in the human body, which increases the risk of increasing radiation absorbed dose. In this study, we have developed the FLUKA transport code, one of the most suitable elements of radiation transport codes, to remove the characteristic X-rays generated by barium or iodine. We have verified the reliability of the shielding fraction of the structure of the structure shielding by comparing with the MCPDX simulations conducted as a prior study. Using the MCNPX and FLUKA, the double layer shielding structures with the various thickness combination consisting of barium sulphate ($BaSO_4$) and bismuth oxide($Bi_2O_3$) are designed. The accuracy of the type shown in IEC 61331-1 was geometrically identical to the simulation. In addition, the transmission spectrum and absorbed dose of the shielding material for the successive x-rays of 120 kVp spectra were compared with lead. In results, $0.3mm-BaSO_4/0.3mm-Bi_2O_3$ and $0.1mm-BaSO_4/0.5mm-Bi_2O_3$ structures have been absorbed in both 33 keV and 37 keV characteristic X-rays. In addition, for high-energy X-rays greater than 90 keV, the shielding efficiency was shown close to lead. Also, the transport code of the FLUKA's photon transport code was showed cut-off on low-energy X-rays(below 33keV) and is limited to computerized X-rays of the low-energy X-rays. But, In high-energy areas above 40 keV, the relative error with MCNPX was found to be highly reliable within 6 %.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.10a
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• pp.137-146
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• 1995

In this study, it was tested whether lead intoxication could change thiamine content and the thiamine related biochemical factor such as activity of transketolase in the brain, and whether the changes of the myelin composition :s well as the seizure threshold induced by lead intoxication in rats be related to these changes of thiamine status and thiamine related biochemical factors. In addition, it was also tested whether administration of excessive thiamine can reverse the toxic manifestation of lead in lead intoxicated animals. Five groups of Wistar rats were prepared: 1)Control group, 2)lead treated group, 3)thiamine treated group, 4)lead plus thiamine treated group and 5)thiamine deficiency group. Each group of animals was divided into three subgroups based on ages: 3, 7 and 10 weeks of age subgroups. Lead concentration, thiamine content, the activity of transketolase and myelin composition in brain areas and threshold of electric shock seizure were tested in each group. Lead concentrations in all brain regions of lead treated group were higher than those of control group, and those of lead plus thiamine treated group were significantly lower than those of lead treated group. Thiamine contents in the brain regions of lead treated group were significantly lower than those of control group, and those of lead plus thiamine treated group were recovered back to those of control group. Activities of transketolase of lead treated group were significantly lower than those of control group, while those of lead plus thiamine treated group were recovered back to those of control group. The cases of which was observed with the concomitant changes of thiamine content and transketolase activity in myelin content or constituent of all the brain regions tested were total amount of myelin protein in the cerebellum of 3 week old rats, and phospholipid in the cerebellum of 3 week old rats and the telencephalon of 16 week old rats. Thresholds of the electroshock seizure of lead-treated group and thiamine-deficient group in 3, 7 week old rats were significantly lower than those of control group, while those of the lead plus thiamine-treated group were similar to those of control group. Changes of the electroshock seizure threshold induced by lead intoxication were observed in 3 week and 7 week old animals with the concomitant decrement of thiamine content in all the brain regions tested. These observations were reversed by the supplementation with thiamine to those animals. However, the changes of seizure threshold induced by lead intoxication corelated with the changes of thiamine contents as well as. transketolase due to lead intoxication. The changes of myelin phospholipid as one of myelin composition and those of myelin Protein content only in the cerebellum of 3 week old rats correlated with the changes of the seizure threshold as well as thiamine content due to lead intoxication. The results from the present study may indicate that neurotoxicity of lead in rats may be mediated at least in part through the changes of thiamine status. Such changes of thiamine status may induce the changes of myelin composition such as myelin phospholipid and those of myelin protein content especially in the cerebellum of 3 week old rats which may eventually affect the threshold of seizure.

• Journal of Plant Biotechnology
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• v.41 no.3
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• pp.146-158
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• 2014

Camelina sativa that belongs to Brassicaceae family is an emerging oilseed crop. Camelina seeds contain approximately 40% storage oils per seed dry weight, which are useful for human and animal diets and industrial applications. Microsomal delta-12 fatty acid desaturase2 (FAD2) catalyzes the conversion of oleic acid to linoleic acid. The polymorphisms of FAD2 genes are correlated with the levels of oleic acids in seed oils. Microsomal delta-12 fatty acid desaturase2 (FAD2) catalyzes the conversion of oleic acid to linoleic acid. The polymorphisms of FAD2 genes are correlated with the levels of oleic acids in seed oils. In this study, three CsFAD2 genes (CsFAD2-1, CsFAD2-2 and CsFAD2-3.1) were isolated from developing seeds of Camelina sativa (L.) cv. CAME. The nucleotide and deduced amino acid sequences of three CsFAD2 genes were compared with those from dicotyledon and monocotyledon plants including Camelina cultivars Sunesone and SRS933. Three histidine motifs (HECGH, HRRHH, and HVAHH) required for FAD activity and a hydrophobic valine or isoleucine residue, which is a SNP (single nucleotide polymorphism) marker related with enzyme activity are well conserved in three CsFAD2s. The expressions of CsFAD2-1 and CsFAD2-3.1 were ubiquitously detected in various Camelina organs, whereas the CsFAD2-2 transcripts were predominantly detected in flowers and developing seeds. The contents of oleic acids decreased, whereas the amounts of linoleic acid increased in dry seeds of transgenic fad2-2 lines expressing each CsFAD2 gene compared with fad2-2 mutant, indicating that three CsFAD2 genes are functionally active. The isolated CsFAD2 genes might be applicable in metabolic engineering of storage oils with high oleic acids in oilseed crops.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.180-187
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• 2016

Purpose: This study described the post-exposure prophylaxis (PEP) and secondary varicella infection in children inadvertently exposed to varicella zoster virus (VZV) in the hospital. Methods: We retrospectively analyzed data from patients with VZV infection who were initially not properly isolated, as well as children exposed to VZV at the Seoul National University Children's Hospital between January 2010 and December 2015. The PEP measures were determined by the presence of immunity to VZV and immunocompromising conditions. Patient clinical information was reviewed via medical records. Results: Among 147 children hospitalized between 2010 and 2015, 13 inadvertent exposures were notified due to VZV infection. Five index children had a history of VZV vaccination. Eighty-six children were exposed in multi-occupancy rooms and 62.8% (54/86) were immune to VZV. The PEP measures administered to 27 exposed patients included varicella zoster immunoglobulin and VZV vaccination. Four children developed secondary varicella, which was linked to a single index patient, including one child who did not receive PEP and three of the 27 children who received PEP. The rates of secondary varicella and prophylaxis failure were 4.7% (4/85) and 11.1% (3/27), respectively. The secondary varicella rates were 1.9% (1/54) and 9.7% (3/31) among immunocompetent and immunocompromised children, respectively. Conclusions: Delayed diagnosis of VZV infection can lead to unexpected exposure and place susceptible children and immunocompromised patients at risk for developing varicella. The appropriateness of the current PEP strategy based on VZV immunity may require re-evaluation.

• Pediatric Infection and Vaccine
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• v.26 no.3
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• pp.148-160
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• 2019

Purpose: This study aimed to investigate the molecular epidemiology of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak at a newborn nursery and neonatal intensive care unit (NICU). Methods: During the outbreak, from August to September 2017, MRSA isolates collected from neonates and medical staff underwent genotyping and screened for virulence factors. Antibiotic susceptibilities were tested. Results: During the study period, 41 neonates were admitted at the nursery (n=27) and NICU (n=14). Of these, 7 had MRSA infections (skin infection [n=6] and sepsis [n=1]) and 4 were colonized with MRSA. Associated medical staff (n=32) were screened; three were nasal MRSA carriers. Staphylococcal chromosomal cassette mec (SCCmec) type II, sequence type (ST) 89, spa type t375 was found to be the skin infection outbreak causing strain, with multi-drug resistance including low-level mupirocin resistance. SCCmec type IVa, ST 72, and a novel spa type designated t17879, was the cause of MRSA sepsis. Many different types of MRSA were colonized on the neonates; however, SCCmec type IVa, ST 72, spa type t664 was colonized in both neonates and a NICU nurse. All MRSA isolates from colonized infants were positive for the Panton-Valentine leukocidin (PVL) toxin gene. Conclusions: The strain causing an outbreak of skin infections had multi-drug resistance. Also, MRSA colonized in the neonates were found to carry the PVL toxin gene. Because different strains are present during an outbreak, molecular epidemiologic studies are important to identify the outbreak strain and colonized strains which aid in effective control and prevention of future MRSA outbreaks.