Publications by authors named "Byung Sun Choi"

55 Publications

Risk of Nonalcoholic Fatty Liver Disease Is Associated with Urinary Phthalate Metabolites Levels in Adults with Subclinical Hypothyroidism: Korean National Environmental Health Survey (KoNEHS) 2012-2014.

Int J Environ Res Public Health 2022 03 10;19(6). Epub 2022 Mar 10.

Department of Convergence Science, College of Medicine, Catholic Kwandong University International St. Mary's Hospital, Incheon 22711, Korea.

Nonalcoholic fatty liver disease (NAFLD) is a condition of excess accumulation of fats in the liver. Thyroid dysfunction is commonly observed in adult populations with NAFLD. In subjects with thyroid dysfunction, phthalates, which are chemical compounds widely used to increase the flexibility of various plastic products, may increase the risk of NAFLD prevalence. Therefore, our study aimed to evaluate the relationship between the levels of urinary phthalate metabolites and the risk of NAFLD stratified by the levels of thyroid-stimulating hormone (TSH). Data ( = 2308) were obtained from the Korean National Environmental Health Survey II (2012-2014). Using the hepatic steatosis index, participants were classified into non-NAFLD (<30) and NAFLD (>36) groups. Participants with euthyroidism were defined as 0.45-4.5 mIU/L for serum TSH and normal thyroxine (T4) levels ( = 2125). Subclinical hypothyroidism (SCH) was defined as a higher TSH level (4.5-10 mIU/L) with normal total T4 levels in the serum ( = 183). A multivariate analysis was performed to assess the association of the urinary phthalate concentration with the risk of NAFLD after stratification based on the thyroid hormone levels. The levels of phthalate metabolites in urine were not significantly associated with NAFLD in adults with euthyroidism. However, a significant increased risk of NAFLD in those with SCH was observed in the fourth quartile of mono (2-ethyl-5-hydroxyhexyl) phthalate (odds ratio (OR) 13.59, 95% confidence interval (CI) 12.13-86.44), mono (2-ethyl-5-oxohexyl) phthalate (OR 8.55, 95% CI 1.20-60.53), mono-(2-ethyl-5-carboxypentyl) phthalate (OR 9.06, 95% CI 1.78-45.96), and mono-benzyl phthalate (OR 6.05, 95% CI 1.62-22.54) compared to those of the lowest quartile after being adjusted with covariates. In conclusion, the levels of phthalate metabolites in urine are positively associated with NAFLD in adults with SCH. More experimental studies are needed to clarify the risk of NAFLD caused by phthalate exposure in cases with poor thyroid function.
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http://dx.doi.org/10.3390/ijerph19063267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8949399PMC
March 2022

High-Resolution Knee Plain Radiography Image Synthesis Using Style Generative Adversarial Network Adaptive Discriminator Augmentation.

J Orthop Res 2022 Mar 16. Epub 2022 Mar 16.

Department of Orthopedic Surgery, Seoul National University Hospital, Jongno-gu, Korea.

In this retrospective study, 10,000 anteroposterior (AP) radiography of the knee from a single institution was used to create medical dataset that are more balanced and cheaper to create. Two types of convolutional networks were used, deep convolutional GAN (DCGAN) and Style GAN Adaptive Discriminator Augmentation (StyleGAN2-ADA). To verify the quality of generated images from StyleGAN2-ADA compared to real ones, the Visual Turing test was conducted by two computer vision experts, two orthopedic surgeons, and a musculoskeletal radiologist. For quantitative analysis, the Fréchet inception distance (FID), and principal component analysis (PCA) were used. Generated images reproduced the features of osteophytes, joint space narrowing, and sclerosis. Classification accuracy of the experts was 34, 43, 44, 57, and 50%. FID between the generated images and real ones was 2.96, which is significantly smaller than another medical dataset (BreCaHAD = 15.1). PCA showed that no significant difference existed between the PCs of the real and generated images (P > 0.05). At least 2000 images were required to make reliable images optimally. By performing PCA in latent space, we were able to control the desired PC that show a progression of arthritis. Using a GAN, we were able to generate knee X-ray images that accurately reflected the characteristics of the arthritis progression stage, which neither human experts, nor artificial intelligence could discern apart from the real images. In summary, our research opens up the potential to adopt a generative model to synthesize realistic anonymous images that can also solve data scarcity and class inequalities. This article is protected by copyright. All rights reserved.
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http://dx.doi.org/10.1002/jor.25325DOI Listing
March 2022

Exposure Levels and Contributing Factors of Various Arsenic Species and Their Health Effects on Korean Adults.

Arch Environ Contam Toxicol 2022 Apr 7;82(3):391-402. Epub 2022 Feb 7.

Department of Preventive Medicine, College of Medicine, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Korea.

Arsenic is a human carcinogen. Data on urinary arsenic species analyses of Koreans are limited. This study evaluated the arsenic exposure level, contributing factors, and health effects in Korean adults. Dietary intake information and urine samples were obtained from 2044 participants. Arsenic exposure was assessed based on urinary concentrations of arsenic species, such as inorganic arsenic, As(III) and As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AsB), using high-performance liquid chromatography with inductively coupled plasma mass spectrometry, followed by determination of biomarkers, malondialdehyde and c-peptide. The geometric mean concentrations were 30.9 μg/L for the sum of inorganic arsenic and their metabolites, and 84.7 μg/L for the total sum of arsenic measured. Urinary concentrations of arsenic species were influenced by age, inhabitant area (inland or coastal), and seafood intake, which was positively correlated with inorganic arsenic, DMA, and AsB. Rice intake was positively correlated with inorganic arsenic and its metabolites but not with AsB. Additionally, malondialdehyde and c-peptide levels were significantly associated with urinary concentrations of various arsenic species. Seafood and rice are major sources of organic/inorganic arsenic exposure in Korean adults; however, it is necessary to evaluate whether their overconsumption could have a potentially detrimental effect on human health.
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http://dx.doi.org/10.1007/s00244-022-00913-yDOI Listing
April 2022

Effect of Leg Length Discrepancy on Lateral Center-edge Angle Measurement.

J Pediatr Orthop 2022 Mar;42(3):e295-e300

Division of Paediatric Orthopaedics, Seoul National University College of Medicine, Seoul National University Children's Hospital, Jongno-gu, Seoul, Republic of Korea.

Background: In patients with leg length discrepancy (LLD) and consequent pelvic obliquity, either the longitudinal axis of the pelvis or a line perpendicular to the ground may be used as the longitudinal reference line for measuring the lateral center-edge angle (LCEA). We aimed to (1) systematically inspect which longitudinal reference line has been used for measuring the LCEA in previous studies; (2) evaluate the frequency of change in the radiographical classification of acetabular overcoverage or undercoverage per the longitudinal reference line; and (3) validate the trigonometric method, predicting the change in the LCEA according to the LLD.

Methods: Studies investigating the LCEA published between January 1976 and July 2019 in the MEDLINE database were categorized according to the longitudinal reference line used. Further, in a retrospective analysis of 238 patients surgically treated for LLD, the LCEA was first measured on standing pelvic radiographs using the longitudinal axis of the pelvis (pLCEA) and measured again using a line perpendicular to the ground (gLCEA). Femoral head coverage was categorized as undercoverage, normal, or overcoverage based on the pLCEA and gLCEA. The theoretically calculated difference between the pLCEA and gLCEA (dLCEA) as determined using a trigonometric method was compared with the dLCEA measured on radiographs.

Results: Of 229 previous studies, 188 did not specify the longitudinal reference line. The number of patients who were diagnosed with acetabular overcoverage using the pLCEA and gLCEA was one and fourteen, respectively (P<0.001). The number of patients who were diagnosed with acetabular undercoverage using the pLCEA and gLCEA was one and zero, respectively (P=1.000). There was no difference (P=0.433) between the theoretically calculated (9±5 degrees) and measured (9±5 degrees) dLCEAs.

Conclusions: The definition of the longitudinal reference line should be clarified when measuring the LCEA. The trigonometric method can accurately predict the change in the LCEA according to LLD in concentric hips without proximal femoral and pelvic deformities.

Level Of Evidence: Level IV-diagnostic study.
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http://dx.doi.org/10.1097/BPO.0000000000002034DOI Listing
March 2022

Three-dimensional printed polylactic acid scaffold integrated with BMP-2 laden hydrogel for precise bone regeneration.

Biomater Res 2021 Oct 27;25(1):35. Epub 2021 Oct 27.

Department of Orthopedic Surgery, SMG-SNU Boramae Medical Center, 39 Boramae Gil, Dongjak-Gu, Seoul, 156-707, South Korea.

Background: Critical bone defects remain challenges for clinicians, which cannot heal spontaneously and require medical intervention. Following the development of three-dimensional (3D) printing technology is widely used in bone tissue engineering for its outstanding customizability. The 3D printed scaffolds were usually accompanied with growth factors, such as bone morphometric protein 2 (BMP-2), whose effects have been widely investigated on bone regeneration. We previously fabricated and investigated the effect of a polylactic acid (PLA) cage/Biogel scaffold as a carrier of BMP-2. In this study, we furtherly investigated the effect of another shape of PLA cage/Biogel scaffold as a carrier of BMP-2 in a rat calvaria defect model and an ectopic ossification (EO) model.

Method: The PLA scaffold was printed with a basic commercial 3D printer, and the PLA scaffold was combined with gelatin and alginate-based Biogel and BMP-2 to induce bone regeneration. The experimental groups were divided into PLA scaffold, PLA scaffold with Biogel, PLA scaffold filled with BMP-2, and PLA scaffold with Biogel and BMP-2 and were tested both in vitro and in vivo. One-way ANOVA with Bonferroni post-hoc analysis was used to determine whether statistically significant difference exists between groups.

Result: The in vitro results showed the cage/Biogel scaffold released BMP-2 with an initial burst release and followed by a sustained slow-release pattern. The released BMP-2 maintained its osteoinductivity for at least 14 days. The in vivo results showed the cage/Biogel/BMP-2 group had the highest bone regeneration in the rat calvarial defect model and EO model. Especially, the bone regenerated more regularly in the EO model at the implanted sites, which indicated the cage/Biogel had an outstanding ability to control the shape of regenerated bone.

Conclusion: In conclusion, the 3D printed PLA cage/Biogel scaffold system was proved to be a proper carrier for BMP-2 that induced significant bone regeneration and induced bone formation following the designed shape.
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http://dx.doi.org/10.1186/s40824-021-00233-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8554986PMC
October 2021

Patterns and Distribution of Deep Vein Thrombosis and Its Effects on Clinical Outcomes After Opening-Wedge High Tibial Osteotomy.

Orthop J Sports Med 2021 Oct 20;9(10):23259671211030883. Epub 2021 Oct 20.

Department of Orthopedic Surgery, Seoul National University College of Medicine, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea.

Background: Although a few studies have reported the incidence of deep vein thrombosis (DVT) after opening-wedge high tibial osteotomy (OWHTO), previous studies focused only on symptomatic DVT. Information is lacking regarding the overall incidence of DVT after OWHTO, thrombus location, and the relationship between DVT and clinical outcome.

Purpose: To determine the overall incidence of DVT and classify the location of DVT after OWHTO. We also determined whether significant differences in clinical improvement exist in patients with and without DVT at 6 months and at 2 years after OWHTO.

Study Design: Case-control study; Level of evidence, 3.

Methods: This study included 46 patients (47 knees) who underwent OWHTO. All patients were instructed to perform knee range of motion exercises and partial weightbearing after drain removal. None of the patients received a chemoprophylaxis for DVT except intermittent pneumatic compression. DVT was diagnosed using 128-row multidetector computed tomography performed before discharge on the fourth postoperative day. The location was classified into 6 segments in the distal portion (muscular and axial veins) and proximal portion (popliteal, femoral, and common femoral veins and veins located above the iliac vein). International Knee Documentation Committee (IKDC) score was assessed preoperatively and postoperatively at 6 months, 1 year, and 2 years using a linear mixed model.

Results: Although the incidence of symptomatic DVT was 8.5% (n = 4), the overall incidence of early DVT was 44.7% (n = 21). All DVTs were located in the distal portion of the lower extremity vein, and 76.2% of the DVTs were located in an axial vein. The IKDC scores were 33.6 ± 7.2 and 35.3 ± 9.1 ( = .910) preoperatively, 38.1 ± 5.6 and 40.6 ± 8.4 ( = .531) at 6 months after surgery, and 44.8 ± 6.9 and 45.9 ± 11.4 ( = .786) at 2 years after surgery in patients without and those with DVT, respectively.

Conclusion: The overall incidence of early DVT after OWHTO was 44.7%. DVT after OWHTO was found particularly around the osteotomy site (76.2%). Patients with DVT did not have inferior short-term clinical outcomes after surgery.
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http://dx.doi.org/10.1177/23259671211030883DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8532235PMC
October 2021

Mini-Screws-Only Fixation Method for Small Fragments of Medial Malleolus Fractures.

Clin Orthop Surg 2021 Sep 3;13(3):307-314. Epub 2021 Jun 3.

Department of Orthopedic Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.

Backgroud: Open reduction and internal fixation is the standard treatment for a displaced medial malleolus fracture (MMFx), achieving ankle stability and bony union to prevent post-traumatic arthritis. Previous fixation techniques including tension band wiring and unicortical screw fixation are not optimal for fixation of small fragments in MMFx due to their small size and poor manipulability. Here, we describe a novel surgical method using mini-screws only for fixation of small fragments in MMFx.

Methods: We conducted a retrospective consecutive study of patients who underwent surgery using mini-screws for small fragment MMFx between April 2013 and March 2018. We reviewed the patients' clinical characteristics and assessed the fracture features radiographically. Clinical outcomes were assessed by measuring the range of motion of both ankle joints and investigating symptomatic implants. We reviewed the radiographic outcomes of the medial malleolus and the functional outcomes using the Foot and Ankle Outcome Score (FAOS) at the last follow-up.

Results: Nine patients were included in the study. The minimal follow-up period was 27 months. There was no incidental bone breakage during the procedure. All MMFx healed without reduction loss, nonunion, or implant failure at the last follow-up. Two patients had mild osteoarthritic changes of the ankle joint. The mean FAOS score of the patients was 80.99 (range, 65.44-98.42). No patients required removal of the hardware.

Conclusions: Fixation of comminuted fractures of the medial malleolus using mini-screws for young adult patients is a straightforward and simple technique. Safe fixation of the anterior and posterior colliculi reduces the risk of implant irritation symptoms that necessitate implant removal.
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http://dx.doi.org/10.4055/cios20293DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8380529PMC
September 2021

Changes in the Occurrence of Gastrointestinal Infections after COVID-19 in Korea.

J Korean Med Sci 2021 Jun 21;36(24):e180. Epub 2021 Jun 21.

Department of Pediatrics, Chung-Ang University Hospital, Seoul, Korea.

Background: After the global epidemic of coronavirus disease 2019 (COVID-19), lifestyle changes to curb the spread of COVID-19 (e.g., wearing a mask, hand washing, and social distancing) have also affected the outbreak of other infectious diseases. However, few studies have been conducted on whether the incidence of gastrointestinal infections has changed over the past year with COVID-19. In this study, we examined how the incidence of gastrointestinal infections has changed since COVID-19 outbreak through open data.

Methods: We summarized the data on the several viruses and bacteria that cause gastrointestinal infections from the open data of the Korea Disease Control and Prevention Agency for 3 years from March 2018 to February 2021 (from Spring 2018 to Winter 2020). Moreover, we confirmed three most common legal gastrointestinal infectious pathogens from March 2016.

Results: From March 2020, when the COVID-19 epidemic was in full swing and social distancing and personal hygiene management were heavily emphasized, the incidence of infection from each virus was drastically decreased. The reduction rates compared to the averages of the last 2 years were as follows: total viruses 31.9%, norovirus 40.2%, group A rotavirus 31.8%, enteric adenovirus 13.4%, astrovirus 7.0%, and sapovirus 12.2%. Among bacterial pathogens, the infection rates of and did not decrease but rather increased in some periods when compared to the average of the last two years. The incidence of nontyphoidal , , or enteropathogenic somewhat decreased but not significantly compared to the previous two years.

Conclusion: The incidence of infection from gastrointestinal viruses, which are mainly caused by the fecal-to-oral route and require direct contact among people, was significantly reduced, whereas the incidence of bacterial pathogens, which have food-mediated transmission as the main cause of infection, did not decrease significantly.
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http://dx.doi.org/10.3346/jkms.2021.36.e180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8216988PMC
June 2021

Effects of Exposure to Lead and Cadmium on Health of Inhabitants of Abandoned Metal Mine Area in Korea.

Arch Environ Contam Toxicol 2021 Feb 6;80(2):490-498. Epub 2021 Feb 6.

College of Medicine, Chung-Ang University, Seoul, Korea.

People living near abandoned mines are at increased risk of exposure to toxic metals. We surveyed 4500 inhabitants with the mean age of 68.5 years old (male: 1768, female: 2732) living near 104 abandoned metal mines from 2013 to 2017 (the 2nd phase health survey in Korea). We conducted personal interviews, blood and urine sampling, and analyzed the concentrations of lead (Pb) and cadmium (Cd) in whole blood and Cd in urine using a graphite furnace atomic absorption spectrometer. The geometric means of blood Pb, blood Cd, and urine Cd were 2.27 μg/dL, 1.42 μg/L, and 1.66 μg/g creatinine, respectively. The level of metal exposure was lower than that reported from the first phase health survey in Korea (2008‒2011) but was higher than in the general population of Korea. Blood Pb was higher in males while blood Cd and urine Cd were significantly higher in females. Blood Pb was highest in the 40‒59 age group, while blood and urine Cd levels continuously increased until age 80 or older. The Cd levels in blood and urine were affected by consumption of locally produced rice and duration of residence near abandoned mines. Furthermore, negative correlations were observed between blood Pb and blood and urine Cd levels. Additionally, 252 of the 4500 subjects exceeded the thresholds of blood Cd or urine Cd levels. Together, these findings suggest that Cd has more sustainable and adverse health effects on the abandoned mine inhabitants, who are mostly aged. Therefore, continuous biomonitoring and risk assessment to environmental health risks are necessary for environmental pollution control and health promotion.
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http://dx.doi.org/10.1007/s00244-021-00813-7DOI Listing
February 2021

Internet gaming disorder and gaming disorder in the context of seeking and not seeking treatment for video-gaming.

J Psychiatr Res 2020 10 7;129:31-39. Epub 2020 Jun 7.

Department of Psychiatry, Chung-Ang University Hospital, Seoul, Republic of Korea. Electronic address:

The aims of this study were to examine the relationship between Internet gaming disorder (IGD) and gaming disorder (GD) and the degree of concordance between treatment seeking for gaming and IGD/GD. One hundred gamers who sought treatment for their gaming were compared with one hundred gamers who never sought treatment and gamers who met IGD and/or GD criteria were compared with those who did not meet these criteria, regardless of their treatment-seeking status. These comparisons were made using semi-structured diagnostic interviews and self-report psychopathology and symptom measures. There was only a partial concordance between treatment seeking and IGD/GD because 61% of treatment-seeking gamers met the diagnostic criteria for IGD and 36% met the diagnostic criteria for GD. GD criteria were found to reflect a more intense, pathological pattern of gaming, associated with high rates of attention deficit/hyperactivity disorder (ADHD) and coping as the main reason for gaming. IGD criteria were found to refer to a broad, heterogeneous entity that encompasses a "spectrum" of gaming from risky/hazardous to pathological. These findings suggest that gamers may seek treatment for IGD/GD, a diagnostically subthreshold, risky gaming pattern (i.e., hazardous gaming) or for a gaming pattern that seems normal. A partial overlap between IGD and GD indicates that the two disorders as conceptualized by their respective criteria, should not be considered interchangeably. The relationship and extent of the conceptual overlap between ADHD and a gaming-related disorder, especially GD, merit further study.
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http://dx.doi.org/10.1016/j.jpsychires.2020.06.007DOI Listing
October 2020

Copper-zinc imbalance induces kidney tubule damage and oxidative stress in a population exposed to chronic environmental cadmium.

Int Arch Occup Environ Health 2020 04 15;93(3):337-344. Epub 2019 Nov 15.

Department of Preventive Medicine, College of Medicine, Chungbuk National University, 1 Chungdae-ro, Seowon-gu, Cheongju, 28644, Republic of Korea.

Purpose: This cross-sectional study aimed to assess the effect of environmental cadmium (Cd) exposure and essential metal imbalance on renal tubular damage and oxidative stress in 979 adults living in a Cd-polluted area near an abandoned copper (Cu) refinery.

Methods: We analyzed urinary Cd concentrations, renal tubular damage and oxidative stress markers, such as beta-2 microglobulin (β2-MG) and N-acetyl-β-D-glucosaminidase (NAG) activity and urine malondialdehyde (MDA) levels. The serum copper-to-zinc ratio (CZR) was used as an essential metal imbalance indicator. We divided the subjects into two Cd exposure groups based on the reference level of urinary Cd for renal dysfunction (2 μg/g creatinine).

Results: The geometric mean concentration of urinary Cd in all subjects was 2.25 μg/g creatinine. In both low and high Cd exposure groups, urinary Cd levels were positively correlated with urinary NAG activity, but not with serum CZR. After multivariate adjustment, serum CZR was strongly associated with urinary β2-MG levels in the low Cd exposure group (β = 1.360, P = 0.019) and was significantly associated with urinary MDA levels, regardless of Cd exposure level. In addition, the risk of renal tubular damage was significantly associated with urinary Cd level, particularly in the lowest or highest CZR tertile groups.

Conclusions: Essential metal imbalance may be a determinant of oxidative stress and renal tubular damage in a chronically Cd-exposed population, and proper zinc supplementation will be effective in preventing adverse health effects due to Cd exposure.
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http://dx.doi.org/10.1007/s00420-019-01490-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078142PMC
April 2020

Derivation of occupational exposure limits for multi-walled carbon nanotubes and graphene using subchronic inhalation toxicity data and a multi-path particle dosimetry model.

Toxicol Res (Camb) 2019 Jul 28;8(4):580-586. Epub 2019 May 28.

Department of Preventive Medicine , College of Medicine , Chung-Ang University , Seoul 06974 , Korea . Email: ; ; Tel: +82-2-820-5668.

In this study, we aimed to provide the recommended occupational exposure limits (OELs) for multi-walled carbon nanotubes (MWCNTs) and graphene nanomaterials based on data from a subchronic inhalation toxicity study using a lung dosimetry model. We used a no observed adverse effect level (NOAEL) of 0.98 mg m and 3.02 mg m in rats for MWCNTs and graphene, respectively. The NOAELs were obtained from a 13-week inhalation study in rats. The deposition fractions of MWCNTs and graphene in the respiratory tract of rats and humans were calculated by using the multi-path particle dosimetry model (MPPD model, v3.04). The deposition fraction in the alveolar region was 0.0527 and 0.0984 for MWCNTs and 0.0569 and 0.1043 for graphene in rats and human lungs, respectively. Then, the human equivalent exposure concentrations (HECs) of MWCNTs and graphene were calculated according to the method by the National Institute for Occupational Safety and Health (NIOSH). The HEC was estimated to be 0.17 mg m for MWCNTs and to be 0.54 mg m for graphene, which was relevant to the rat NOAEL of 0.98 mg m and 3.02 mg m for MWCNTs and graphene, respectively. Finally, we estimated the recommended OELs by applying uncertainty factors (UFs) to the HEC as follows: an UF of 3 for species differences (rats to humans), 2 for an experimental duration (subchronic to chronic), and 5 for inter-individual variations among workers. Thus, the OEL was estimated to be 6 μg m for MWCNTs and 18 μg m for graphene. These values could be useful in preventing the adverse health effects of nanoparticles in workers.
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http://dx.doi.org/10.1039/c9tx00026gDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6624975PMC
July 2019

MRI Assessment of Cerebral Small Vessel Disease in Patients with Spontaneous Intracerebral Hemorrhage.

Yonsei Med J 2019 Aug;60(8):774-781

Department of Preventive Medicine, Chung-Ang University College of Medicine, Seoul, Korea.

Purpose: Cerebral small vessel disease (SVD) is known to be associated with ischemic stroke, intracerebral hemorrhage (ICH), and cognitive impairment. In this retrospective observational study, we explored SVD markers on MRI relevant to spontaneous ICH.

Materials And Methods: The ICH group consisted of 150 consecutive patients with a first primary parenchymal ICH, and the control group consisted of 271 age- and sex-matched individuals who underwent brain MRI in a health care center. We compared cerebral microbleeds (CMBs), white matter hyperintensities (WMHs), enlarged perivascular space (EPVS), and lacunae in the ICH and control groups.

Results: A total of 1278 CMB lesions were identified in 121 of the 150 patients in the ICH group (80.6%), while 77 CMB lesions were found in 32 of the 271 individuals in the control group (11.8%). WMH and EPVS were more severe and lacunae were more frequent in the ICH patients than in the control group. When receiver operating characteristic (ROC) curves were plotted, number of CMBs most significantly predicted ICH. All imaging markers were significantly associated with ICH in every age group. The location of CMBs coincided with the location of ICH, and ICH volume correlated with CMB count.

Conclusion: All MRI markers for SVD were worse in ICH patients than in healthy controls, and these markers were prominent even in young ICH patients. Lacunae, WMH, EPVS, and CMB should be considered as factors related with spontaneous ICH.
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http://dx.doi.org/10.3349/ymj.2019.60.8.774DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6660438PMC
August 2019

Recovery from acute kidney injury as a potent predictor of survival and good neurological outcome at discharge after out-of-hospital cardiac arrest.

Crit Care 2019 Jul 15;23(1):256. Epub 2019 Jul 15.

Department of Emergency Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.

Background: Acute kidney injury (AKI) after out-of-hospital cardiac arrest (OHCA) is a well-known predictor for mortality. However, the natural course of AKI including recovery rate after OHCA is uncertain. This study investigated the clinical course of AKI after OHCA and determined whether recovery from AKI impacted the outcomes of OHCA.

Methods: This retrospective multicentre cohort study included adult OHCA patients treated with targeted temperature management (TTM) between January 2016 and December 2017. AKI was diagnosed using the Kidney Disease: Improving Global Outcomes criteria. The primary outcome was the recovery rate after AKI and its association with survival and good neurological outcome at discharge.

Results: A total of 3697 OHCA patients from six hospitals were screened and 275 were finally included. AKI developed in 175/275 (64%) patients and 69/175 (39%) patients recovered from AKI. In most cases, AKI developed within three days of return of spontaneous circulation [155/175 (89%), median time to AKI development 1 (1-2) day] and patients recovered within seven days of return of spontaneous circulation [59/69 (86%), median time to AKI recovery 3 (2-7) days]. Duration of AKI was significantly longer in the AKI non-recovery group than in the AKI recovery group [5 (2-9) vs. 1 (1-5) days; P < 0.001]. Most patients were diagnosed with AKI stage 1 initially [120/175 (69%)]. However, the number of stage 3 AKI patients increased from 30/175 (17%) to 77/175 (44%) after the initial diagnosis of AKI. The rate of survival discharge was significantly higher in the AKI recovery group than in the AKI non-recovery group [45/69 (65%) vs. 17/106 (16%); P < 0.001]. Recovery from AKI was a potent predictor of survival and good neurological outcome at discharge in the multivariate analysis (adjusted odds ratio, 8.308; 95% confidence interval, 3.120-22.123; P < 0.001 and adjusted odds ratio, 36.822; 95% confidence interval, 4.097-330.926; P = 0.001).

Conclusions: In our cohort of adult OHCA patients treated with TTM (n = 275), the recovery rate from AKI after OHCA was 39%, and recovery from AKI was a potent predictor of survival and good neurological outcome at discharge.
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http://dx.doi.org/10.1186/s13054-019-2535-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6632185PMC
July 2019

Effect of dietary patterns on the blood/urine concentration of the selected toxic metals (Cd, Hg, Pb) in Korean children.

Food Sci Biotechnol 2018 Aug 24;27(4):1227-1237. Epub 2018 Feb 24.

2Department of Preventive Medicine, School of Medicine, Kangwon National University, Chun-Cheon, Korea.

This study was aimed to examine the association the blood/urinary concentration of toxic metal (Hg, Pb, and Cd) with children's dietary patterns. This cross-sectional study included 1026 school children aged 8-17 years. Dietary patterns were defined using factor loading scores for 108 foods from a Semi-Quantitative Food Frequency Questionnaire. A high blood Hg level was found in boys with a high score in the 'fish' pattern ( = 0.02), and in girls with a high score in 'fruit' pattern ( = 0.04). The concentration of Pb was related to the 'imprudent' pattern in high school boys ( = 0.02). The effect of the 'vegetable' pattern on high excretion of urinary Cd was observed in low grade elementary ( = 0.04) and middle school students ( < 0.0001), and the effect of the 'fruit' pattern on the urinary Cd was observed in high grade elementary school students ( = 0.02). This study suggests that the concentration of selected toxic metals in blood/urine could be affected by children's dietary pattern.
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http://dx.doi.org/10.1007/s10068-018-0336-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6085261PMC
August 2018

Analysis of seasonal tendencies in pediatric Henoch-Schönlein purpura and comparison with outbreak of infectious diseases.

Medicine (Baltimore) 2018 Sep;97(36):e12217

Department of Pediatrics Department of Pediatrics, College of Medicine Department of Preventive Medicine, College of Medicine, Chung-Ang University, Seoul, Korea.

Henoch-Schönlein purpura (HSP) is one of the most common vasculitis in children. This study was aimed at identifying seasonal trends and epidemiologic features of pediatric HSP patients through public data to analyze the correlation of HSP and prevalence of a specific respiratory or enteric virus.We extracted information on pediatric HSP patients categorized into 4 age groups and data on 8 respiratory and 4 enteric viruses were extracted from national data. We used the decomposition of time series analysis and correlation analysis to identify the incidence of HSP and the prevalence of each virus.From 2013 to 2016, 16,940 patients under the age of 18 were diagnosed with HSP in Korea, 6203 (36.6%) were diagnosed with HSP in middle childhood. Spring had the largest number of patients (5252, 31.0%), and summer had the smallest number of patients (3224, 19.0%). The largest and smallest number of cases occurred in March (1949, 11.5%) and August (959, 5.7%), respectively. However, among the adolescents, more patients were diagnosed in the summer (985, 24.8%) than in the fall (760, 19.1%). The positive detection counts of most viruses showed apparent seasonal variations. Depending on the age group, the epidemic patterns of influenza and rotaviruses were temporally and statistically similar to that of HSP.We have confirmed that the occurrence of pediatric HSP in Korea shows a seasonal tendency, which is age-dependent and related to exposure to infectious agents and suggest some respiratory or enteric viruses may play an important role in pathophysiology.
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http://dx.doi.org/10.1097/MD.0000000000012217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6133644PMC
September 2018

Lead, Mercury, and Cadmium Exposure in the Korean General Population.

J Korean Med Sci 2018 Jan 8;33(2):e9. Epub 2018 Jan 8.

Department of Preventive Medicine, College of Medicine, Chung-Ang University, Seoul, Korea.

Background: Lead (Pb), mercury (Hg), and cadmium (Cd) are well-known environmental pollutants. They are unnecessary in the biological processes of humans. This study was performed to estimate the representative background exposure levels to the metals by measuring concentrations in whole blood of the Korean general population.

Methods: This population-based cross-sectional study included 4,000 subjects (1,886 males and 2,114 females) 0-83 years of age in 2010 and 2011. Adult subjects (≥ 19 years of age) were collected by sex- and age-stratified probability method, and preschool- and school-aged subjects were recruited by a cluster sampling method. Written consent was provided prior to blood sampling. Pb and Cd blood concentrations were determined by a flameless atomic absorption spectrophotometry, and blood Hg was analyzed by a direct Hg analyzer.

Results: The geometric mean, median and 95th percentile of blood Pb was 1.82 μg/dL, 1.83 μg/dL, and 3.78 μg/dL, respectively. The respective values were 2.92 μg/L, 2.87 μg/L, 9.12 μg/L for Hg, and 0.56 μg/L, 0.59 μg/L, 2.20 μg/L for Cd. Blood Pb and Hg were higher in males than in females, but no sex difference was observed, respectively, in subjects 0-4 years of age for Pb and in subjects less than 20 years for Hg. However, blood Cd was higher in females than in males and no sex difference was observed in subjects < 30 years of age.

Conclusion: This study provides representative data of human exposure to Pb, Hg, and Cd covering whole age groups of the general population in Korea.
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http://dx.doi.org/10.3346/jkms.2018.33.e9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5729657PMC
January 2018

Dramatic psychiatric and behavioral symptoms following a subthalamic lesion.

J Clin Neurosci 2018 Jan 4;47:154-156. Epub 2017 Nov 4.

Department of Neurology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea. Electronic address:

Neuropsychiatric symptoms have been well documented after subthalamic nucleus deep brain stimulation (STN-DBS), but those following a subthalamic lesion have been rarely reported. Herein, we present a 43-year-old woman with sudden-onset dramatic psychiatric and behavioral symptoms with hemiballism. Brain magnetic resonance imaging (MRI) with fluid attenuated inversion recovery (FLAIR) sequence during the acute phase demonstrated extensive hyperintensity in the left STN and adjacent regions. Contrast-enhanced MRI showed no abnormal areas of enhancement. Magnetic resonance venography (MRV) was normal. Routine blood and cerebrospinal fluid (CSF) tests were not remarkable. Autoimmune antibodies showed no significant results. A gradual recovery of both psychiatric and behavioral symptoms and hemiballism was observed with steroid and symptomatic treatment. Our case is unique in dramatic neuropsychiatric symptoms following a subthalamic lesion. We would like to point out that severe neuropsychiatric symptoms can occur in the patients with subthalamic lesions, and can be a troubling feature in their management.
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http://dx.doi.org/10.1016/j.jocn.2017.10.051DOI Listing
January 2018

Low-Level Environmental Cadmium Exposure Induces Kidney Tubule Damage in the General Population of Korean Adults.

Arch Environ Contam Toxicol 2017 Oct 17;73(3):401-409. Epub 2017 Aug 17.

Department of Preventive Medicine, College of Medicine, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, 156-756, Korea.

Cadmium (Cd) is the most potent nephrotoxic heavy metal and may affect bone; it also has a long biological half-life in the human body. This study was designed to assess the effect of environmental low-level Cd exposure on kidney function and bone in the general population. The subjects of this cross-sectional study were 1907 healthy Korean adults who had not been exposed to Cd occupationally. We analyzed the concentrations of Cd in the urine, markers of renal tubule damage, such as β-microglobulin (β-MG) and N-acetyl-β-D-glucosaminidase (NAG) activity in the urine, calculated the estimated glomerular filtration rate (eGFR) using serum creatinine, and measured bone mineral density (BMD). Also, we analyzed malondialdehyde (MDA) levels in the urine. The geometric mean concentration of Cd in urine was higher in women (1.36 μg/g creatinine) than in men (0.82 μg/g creatinine). Urinary Cd was significantly positively correlated with urinary β-MG and NAG activity, whereas it was negatively correlated with eGFR and BMD. The risk of renal tubule damage was significantly associated with urine Cd level, and the association remained significant after controlling for various confounding variables. However, no association was observed between urinary Cd level and glomerular dysfunction or bone damage. The concentration of MDA was increased with urinary Cd level in a dose-dependent manner. These findings suggest that low-level environmental Cd exposure may cause microscopic damage to renal tubules through oxidative stress but might not impair kidney glomeruli or bones.
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http://dx.doi.org/10.1007/s00244-017-0443-4DOI Listing
October 2017

Exome-wide association study identifies genetic polymorphisms of C12orf51, MYL2, and ALDH2 associated with blood lead levels in the general Korean population.

Environ Health 2017 02 17;16(1):11. Epub 2017 Feb 17.

Department of Preventive Medicine, College of Medicine, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, Chungbuk, 28644, Korea.

Background: Lead (Pb) is a ubiquitous toxic metal present in the environment that poses adverse health effects to humans. Inter-individual variation in blood Pb levels is affected by various factors, including genetic makeup. However, limited data are available on the association between genetic variation and blood Pb levels. The purpose of this study was to identify the genetic markers associated with blood Pb levels in the Korean population.

Methods: The study subjects consisted of 1,483 healthy adults with no history of occupational exposure to Pb. We measured blood Pb levels and calculated probable daily intake of Pb according to dietary data collected using 24-hour recall. We conducted exome-wide association screening using Illumina Human Exome-12v1.2 platform (n = 500) and a replication analysis using VeraCode Goldengate assay (n = 1,483).

Results: Among the 244,770 single nucleotide polymorphisms (SNPs) tested, 12 SNPs associated with blood Pb level were identified, with suggestive significance level (P < 1 × 10). In the Goldengate assay for replication, three SNPs (C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671) were associated with statistically suggestively significant differences in blood Pb levels. When stratified by drinking status, a potential association of C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 with blood Pb level was observed only in drinkers. A marginally significant gene-environment interaction between ALDH2 rs671 and alcohol consumption was observed in relation to blood Pb levels. The effects of the three suggestively significant SNPs on blood Pb levels was dependent on daily calcium intake amounts.

Conclusions: This exome-wide association study indicated that C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 polymorphisms are linked to blood Pb levels in the Korean population. Our results suggest that these three SNPs are involved in the determination of Pb levels in Koreans via the regulation of alcohol drinking behavior, and that their negative effects may be compensated by appropriate calcium intake.
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http://dx.doi.org/10.1186/s12940-017-0220-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5316181PMC
February 2017

Urinary arsenic species concentration in residents living near abandoned metal mines in South Korea.

Ann Occup Environ Med 2016 22;28:67. Epub 2016 Nov 22.

Heavy Metal Exposure Environmental Health Center, Dong-A University, Busan, Korea ; Department of Preventive Medicine, College of Medicine, Dong-A University, 26, Daesingongwon-ro, Seo-gu, Busan, Korea.

Background: Arsenic is a carcinogenic heavy metal that has a species-dependent health effects and abandoned metal mines are a source of significant arsenic exposure. Therefore, the aims of this study were to analyze urinary arsenic species and their concentration in residents living near abandoned metal mines and to monitor the environmental health effects of abandoned metal mines in Korea.

Methods: This study was performed in 2014 to assess urinary arsenic excretion patterns of residents living near abandoned metal mines in South Korea. Demographic data such as gender, age, mine working history, period of residency, dietary patterns, smoking and alcohol use, and type of potable water consumed were obtaining using a questionnaire. Informed consent was also obtained from all study subjects ( = 119). Urinary arsenic species were quantified using high performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP/MS).

Results: The geometric mean of urinary arsenic (sum of dimethylarsinic acid, monomethylarsonic acid, As, and As) concentration was determined to be 131.98 μg/L (geometric mean; 95% CI, 116.72-149.23) while urinary inorganic arsenic (As and As) concentration was 0.81 μg/L (95% CI, 0.53-1.23). 66.3% ( = 79) and 21.8% ( = 26) of these samples exceeded ATSDR reference values for urinary arsenic (>100 μg/L) and inorganic arsenic (>10 μg/L), respectively. Mean urinary arsenic concentrations (geometric mean, GM) were higher in women then in men, and increased with age. Of the five regions evaluated, while four regions had inorganic arsenic concentrations less than 0.40 μg/L, one region showed a significantly higher concentration (GM 15.48 μg/L; 95% CI, 7.51-31.91) which investigates further studies to identify etiological factors.

Conclusion: We propose that the observed elevation in urinary arsenic concentration in residents living near abandoned metal mines may be due to environmental contamination from the abandoned metal mine.

Trial Registration: Not Applicable (We do not have health care intervention on human participants).
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http://dx.doi.org/10.1186/s40557-016-0150-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5120503PMC
November 2016

Rivastigmine patch reduces the incidence of postoperative delirium in older patients with cognitive impairment.

Int J Geriatr Psychiatry 2017 Oct 26;32(10):1079-1084. Epub 2016 Aug 26.

Department of Orthopaedic Surgery, College of Medicine, Chung-Ang University, Seoul, South Korea.

Objective: To date, data regarding the efficacy of acetylcholinesterase inhibitors in preventing postoperative delirium (POD) are inconsistent and conflicting. Older individuals with cognitive dysfunction are thought to show POD more frequently. Our aim was to study the effectiveness of rivastigmine prophylaxis on the incidence, severity, and risk factors for POD in older patients with cognitive impairment undergoing hip fracture surgery.

Methods: Of 62 older patients with cognitive impairment about to undergo surgery after a hip fracture, 31 were randomly assigned to receive a rivastigmine patch from 3 days before to 7 days after the operation (Group I), and the other 31 did not receive a rivastigmine patch (Group II). The two groups were compared with regard to incidence and severity of delirium on postoperative days 2 or 3 and 7. Multivariate logistic regression analysis was performed to assess factors associated with POD.

Results: Postoperative delirium occurred in five Group I patients and 14 Group II patients (p = 0.013). The mean severity of delirium in the two groups as determined by the Delirium Rating Scale was 2.2 and 6.2 respectively (p = 0.033). The odds ratio for POD was 0.259 (95% CI: 0.074-0.905, p = 0.034) after adjusting for American Society of Anesthesiologists score (p = 0.058), age (p = 0.203), and gender (p = 0.560). There were no rivastigmine-related perioperative complications.

Conclusion: Perioperative rivastigmine patch application could reduce the occurrence of POD in older patients with low cognitive status. Copyright © 2016 John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/gps.4569DOI Listing
October 2017

Allele Frequencies of the Single Nucleotide Polymorphisms Related to the Body Burden of Heavy Metals in the Korean Population and Their Ethnic Differences.

Toxicol Res 2016 Jul 30;32(3):195-205. Epub 2016 Jul 30.

Department of Preventive Medicine, Dankook University College of Medicine, Cheonan, Korea.

This study was performed to select single nucleotide polymorphisms (SNPs) related to the body burden of heavy metals in Koreans, to provide Korean allele frequencies of selected SNPs, and to assess the difference in allele frequencies with other ethnicities. The candidate-gene approach method and genome-wide association screening were used to select SNPs related to the body burden of heavy metals. Genotyping analysis of the final 192 SNPs selected was performed on 1,483 subjects using the VeraCode Goldengate assay. Allele frequencies differences and genetic differentiations between the Korean population and Chinese (CHB), Japanese (JPT), Caucasian (CEU), and African (YIR) populations were tested by Fisher's exact test and fixation index (F ST), respectively. The Korean population was genetically similar to the CHB and JPT populations (F ST < 0.05, for all SNPs in both populations). However, a significant difference in the allele frequencies between the Korean and CEU and YIR populations were observed in 99 SNPs (60.7%) and 120 SNPs (73.6%), respectively. Ten (6.1%) and 26 (16.0%) SNPs had genetic differentiation (F ST > 0.05) among the Korean-CEU and Korean-YIR comparisons, respectively. The SNP with the largest F ST value between the Korean and African populations was cystathionine-β-synthase rs234709 (F ST: KOR-YIR, 0.309; KOR-CEU, 0.064). Our study suggests that interethnic differences exist in SNPs associated with heavy metals of Koreans, and it should be considered in future studies that address ethnic differences in heavy-metal concentrations in the body and genetic susceptibility to the body burden of heavy metals.
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http://dx.doi.org/10.5487/TR.2016.32.3.195DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4946415PMC
July 2016

Environmental Exposure to Arsenic, Lead, and Cadmium in People Living near Janghang Copper Smelter in Korea.

J Korean Med Sci 2016 Apr 22;31(4):489-96. Epub 2016 Feb 22.

Department of Preventive Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea .

Concentrations of heavy metals exceed safety thresholds in the soil near Janghang Copper Refinery, a smelter in Korea that operated from 1936 to 1989. This study was conducted to evaluate the level of exposure to toxic metals and the potential effect on health in people living near the smelter. The study included 572 adults living within 4 km of the smelter and compared them with 413 controls group of people living similar lifestyles in a rural area approximately 15 km from the smelter. Urinary arsenic (As) level did not decrease according to the distance from the smelter, regardless of gender and working history in smelters and mines. However, in subjects who had no occupational exposure to toxic metals, blood lead (Pb) and cadmium (Cd) and urinary Cd decreased according to the distance from the smelter, both in men and women. Additionally, the distance from the smelter was a determinant factor for a decrease of As, Pb, and Cd in multiple regression models, respectively. On the other hands, urinary Cd was a risk factor for renal tubular dysfunction in populations living near the smelter. These results suggest that Janghang copper smelter was a main contamination source of As, Pb, and Cd, and populations living near the smelter suffered some adverse health effects as a consequence. The local population should be advised to make efforts to reduce exposure to environmental contaminants, in order to minimize potential health effects, and to pay close attention to any health problems possibly related to toxic metal exposure.
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http://dx.doi.org/10.3346/jkms.2016.31.4.489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4810329PMC
April 2016

Arsenic levels in the groundwater of Korea and the urinary excretion among contaminated area.

J Expo Sci Environ Epidemiol 2016 09 6;26(5):458-63. Epub 2016 Apr 6.

College of Pharmacy, Seoul National University, Seoul, South Korea.

Drinking water is a main source of human exposure to arsenic. Hence, the determination of arsenic in groundwater is essential to assess its impact on public health. Here, we report arsenic levels in the groundwater of 722 sites covering all six major provinces of Korea. Water was sampled in two occasions (summer, 722 sites and winter, 636 sites) and the arsenic levels were measured with highly sensitive inductively coupled plasma-mass spectrometry method (limit of detection, 0.1 μg/l) to encompass the current drinking water standard (<10 μg/l). Seasonal variation was negligible, but the geographical difference was prominent. Total arsenic in groundwater ranged from 0.1 to 48.4 μg/l. A 88.0-89.0% of sites were <2.0 μg/l and the remaining ones generally did not exceed 10 μg/l (6.4-7.0%, 2.0-4.9 μg/l; 2.4-3.0%, 5.0-9.9 μg/l). However, some areas (1.0-9.2%) exhibited >10 μg/l. Notably, urinary arsenic excretion of people around these regions was markedly higher compared with non-contaminated areas (<5 μg/l) (79.7±5.2 μg/g (N=122) vs 68.4±5.4 μg/g (N=65) creatinine, P=0.052). All stratified analysis also revealed higher urinary excretion, where a statistically significant difference was noted for non-smokers (85.9±12.7 vs 54.0±6.3, P=0.030), suggesting that arsenic-contaminated groundwater may contribute to its systemic exposure.
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http://dx.doi.org/10.1038/jes.2016.16DOI Listing
September 2016

Estimation of Total and Inorganic Arsenic Intake from the Diet in Korean Adults.

Arch Environ Contam Toxicol 2016 May 26;70(4):647-56. Epub 2015 Dec 26.

Department of Preventive Medicine, College of Medicine, Chung-Ang University, 221 Heukseok-Dong, Dongjak-Gu, Seoul, 156-756, Korea.

Arsenic (As) is a major environmental pollutant and a known human carcinogen that is widely distributed in the air, soil, and water. General population is mainly exposed to As through drinking water and food from the contaminated water and soil. Arsenic in drinking water is generally well controlled now. This study was performed to estimate total and inorganic As intake and to determine the major contributing source in the Korean adult diet. The study subjects were 2117 healthy adults (922 males and 1195 females) who had not been occupationally exposed to As. Total dietary intake was studied using the 24-h recall method, which included 138 specific food items. The estimates of total As and inorganic As intake were based on total and inorganic As contents in each food item consumed during the last 24 h. Daily dietary intake was estimated to be 1373.6 g. Total As intake was estimated to be 145.4 µg As/day. Total dietary As intake was correlated with consumption of fish/shellfish, seaweeds, and grains. Approximately 87% of total dietary As intake was attributed to seafood, such as 105.5 µg As/day from fish/shellfish and 20.5 µg As/day from seaweeds. Inorganic As intake was estimated to be 10.4 µg As per day. Inorganic As intake was mainly provided by grains (6.4 µg As/day), followed by seaweeds and fish/shellfish. Our results indicate that seafood and grains are the main As dietary sources in Korean adults and that dietary As exposure may be associated with individual dietary habits and environmental As contamination among countries.
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http://dx.doi.org/10.1007/s00244-015-0257-1DOI Listing
May 2016

Extensive evaluation of DNA polymerase performance for highly degraded human DNA samples.

Forensic Sci Int 2015 Jun 13;251:171-8. Epub 2015 Apr 13.

Institute for Medical Sciences, College of Medicine, Chung-Ang University, Seoul 156-756, Republic of Korea. Electronic address:

Highly degraded human DNA is commonly encountered in the forensic studies. Despite many efforts, the poor quality and quantity of the DNA often result in unsuccessful DNA analysis. There has been no extensive evaluation of DNA polymerase performance for the successful PCR of highly degraded DNA samples. We evaluated the most efficient DNA polymerases, based on real-time PCR and agarose gel electrophoresis analyses for a single copy gene amplification, with 200 ancient DNA (aDNA) samples of various origins. Nine commercially available DNA polymerases were tested, which included enzymes that are reportedly effective for PCR-inhibitory samples. The first screening test for the polymerases with 20 aDNA samples showed that Pico Maxx HF, FastStart Taq, and Ex Taq HS DNA polymerases were the most effective. Further tests with 180 aDNA samples showed that AmpliTaq Gold (control) amplified PCR products from 52 aDNA samples, PicoMaxx HF from 62, FastStart Taq from 64, and Ex Taq HS from 65. The use of two or more of Ex Taq HS, FastStart Taq, and PicoMaxx HF resulted in a significantly higher success rate than that of AmpliTaq Gold alone. With 37 positive samples tested in duplicate, Ex Taq HS showed the highest reproducibility (13 samples) and AmpliTaq Gold, the lowest (four samples); this difference was significant. The data also showed preferential amplification by the enzymes; Ex Taq HS exclusively produced amplification from two samples, FastStart Taq from one, and PicoMaxx HF from one. We suggest that the initial use of these three DNA polymerases will increase the probability of successfully amplifying DNA from highly degraded human DNA samples.
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http://dx.doi.org/10.1016/j.forsciint.2015.04.001DOI Listing
June 2015

Temporal changes in urinary levels of cadmium, N-acetyl-β-d-glucosaminidase and β2-microglobulin in individuals in a cadmium-contaminated area.

Environ Toxicol Pharmacol 2015 Jan 13;39(1):35-41. Epub 2014 Nov 13.

Department of Preventive Medicine, College of Medicine, Chungbuk National University, Cheongju, Chungbuk 362-763, Republic of Korea. Electronic address:

Cadmium (Cd) is a metal that is toxic to renal tubules. If renal tubules are damaged by Cd, urinary excretion of N-acetyl-β-D-glucosaminidase (NAG) and beta 2-microglobulin (β2-MG) increases. The aim of this study was to describe the changing patterns of urinary Cd, NAG, and β2-MG levels over a 3-year period in individuals living in a Cd-contaminated area. This follow-up study included 191 residents (65.6±9.3 years) who were living in the vicinity of a copper refinery. Urinary levels of Cd, NAG activity, and β2-MG levels were measured, and their determinants and changing patterns were analyzed statistically. The natural logarithm of urinary Cd levels decreased significantly over time. Sex and intake of locally cultivated rice were significant determinants of urinary Cd concentration. Urinary NAG activity decreased over time. Age and urinary Cd concentration were significant determinants of urinary NAG activity in subjects with urinary Cd concentrations >5μg/g creatinine. In subjects whose urinary Cd concentrations were >2μg/g creatinine, diabetes was found to be a significant risk factor for high urinary NAG activity. The slope for temporal changes in urinary β2-MG levels was negative in subjects whose urinary Cd levels were <2μg/g creatinine but was positive in those whose urinary Cd levels were 2-5μg/g creatinine or >5μg/g creatinine. The urinary β2-MG levels found in individuals whose urinary Cd levels were >2μg/g creatinine suggest that previous Cd-induced renal tubular damage had occurred.
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http://dx.doi.org/10.1016/j.etap.2014.10.016DOI Listing
January 2015

Mercury-induced amyloid-beta (Aβ) accumulation in the brain is mediated by disruption of Aβ transport.

J Toxicol Sci 2014 Aug;39(4):625-35

Department of Preventive Medicine, College of Medicine, Chung-Ang University.

According to a recent study, mercury (Hg) exposure contributes to Alzheimer's disease (AD). However, the underlying mechanisms are not understood. This study investigated the effect of methylmercury (MeHg) treatment on the generation, degradation, and transport of amyloid β-protein (Aβ) in the brain. Wistar rats were administered MeHg by gavage (0, 20, 200, and 2,000 μg Hg/kg/day) for 4 weeks. The total Hg in the blood and brain regions was measured, and the levels of Aβ42 in plasma, cerebrospinal fluid (CSF), and brain regions were estimated. The expression of amyloid precursor protein (APP), beta-site APP-cleaving enzyme 1 (BACE1), and neprilysin (NEP) in the brain regions was determined, in addition to the expression of low-density lipoprotein receptor-related protein 1 (LRP1) and the receptor for advanced glycation end products (RAGE) in the brain capillary endothelium (BCE). Finally, the amount of soluble low-density lipoprotein receptor-related protein (sLRP) in the plasma was determined. Aβ42 levels were decreased in the CSF of the 2,000 μg Hg/kg/day group compared with controls, and Aβ42 levels increased in the hippocampus (HC) in a dose-dependent manner. MeHg decreased LRP1 expression but increased RAGE levels in BCE. sLRP levels were decreased in the plasma of the MeHg-treated rats. They were positively correlated with CSF Aβ42 and negatively correlated with Aβ42 and Hg levels in HC. These results imply that MeHg reduces the transportation of Aβ, thereby resulting in the accumulation of the protein in the HC. Plasma sLRP levels may be an early biomarker of Hg-induced Aβ accumulation in the brain.
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http://dx.doi.org/10.2131/jts.39.625DOI Listing
August 2014

Differences in the susceptibility to cadmium-induced renal tubular damage and osteoporosis according to sex.

Environ Toxicol Pharmacol 2014 Jul 13;38(1):272-8. Epub 2014 Jun 13.

Department of Preventive Medicine and Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea. Electronic address:

This study aimed to estimate the risks for renal tubular damage and osteoporosis in individuals with long-term environmental Cd exposure. This cross-sectional study comprised 1086 residents living in the vicinity of a copper refinery plant. As the urinary Cd levels increased, the proportion of female subjects with β₂-MG ≥300 μg/g creatinine also increased significantly, but this was not observed in the male subjects. The prevalence of osteoporosis was significantly higher in men with urinary Cd >5 μg/g creatinine than in those with urinary Cd ≤5 μg/g creatinine. This difference was not observed in the corresponding female groups. The association between increased urinary excretion of β₂-MG and decreased BMD was statistically significant only in the female subjects. We suggest that an increased Cd body burden directly decreases the BMD in male subjects; however, in female subjects, it first induces renal microtubular damage, which can lead to osteoporosis.
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http://dx.doi.org/10.1016/j.etap.2014.06.002DOI Listing
July 2014
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