Sang-yon Kim

Assessment of Di (2-ethylhexyl) Phthalate Exposure by Urinary Metabolites as a Function of Sampling Time

OBJECTIVES In most DEHP exposure assessment studies, single spot urine sample was used. It could not compare the exposure level among studies. Therefore, we are going to represent the necessity of selection of proper sampling time of spot urine for assessing the environmental DEHP exposure, and the association urinary DEHP metabolites with steroid hormones. METHODS We collected urine and plasma from 25 men. The urine sampling times were at the end of the shift (post-shift) and the next morning before the beginning of the shift (pre-shift). Three metabolites of DEHP {mono(2-ethylhexyl) phthalate [MEHP], mono-(2-ethyl-5-hydroxyhexyl)phthalate [MEHHP], and mono(2-ethyl-5-oxohexyl)phthalate [MEOHP]} in urine were analyzed by HPLC/MS/MS. Plasma luteinzing hormone, follicle stimulating hormone, testosterone, and 17ß-estradiol were measured at pre-shift using a ELISA kit. A log-transformed creatinine-adjusted urinary MEHP, MEHHP, and MEOHP concentration were compared between the post- and pre-shift. The Pearsons correlation was calculated to assess the relationships between log-transformed urinary MEHP concentrations in pre-shift urine and hormone levels. RESULTS The three urinary metabolite concentrations at post-shift were significantly higher than the concentrations in the pre-shift (p<0.0001). The plasma hormones were not significantly correlated with log-transformed creatinine - adjusted DEHP metabolites. CONCLUSIONS To assess the environmental DEHP exposure, it is necessary to select the urine sampling time according to the study object. There were no correlation between the concentration of urinary DEHP metabolites and serum hormone levels.

Environmentally relevant levels of Bisphenol A may accelerate the development of type II diabetes mellitus in adolescent Otsuka Long Evans Tokushima Fatty rats

Environmental chemicals may contribute to the development of obesity and metabolic disorders such as diabetes. Bisphenol A (BPA) is one of the environmental chemicals that are widely used in daily life. This study was performed to investigate whether low dose BPA exposure can influence the occurrence of type II diabetes mellitus. Four weeks old Otsuka Long Evans Tokushima Fatty (OLETF) rats were randomly assigned to three groups of five animals and each group was given different concentrations of corn oil with BPA (0, 0.001, and 0.1 mg/kg/day). BPA 0.1 mg/kg/ day produced impairment of glucose tolerance, and induced higher insulin (p=0.028) and malondialdehyde levels (p=0.009) in serum than control group. Serum insulin levels in BPA 0.001 mg/kg/day treated group showed significantly higher than the control group (p=0.016). BPA tended to induce down-regulation of PPARγ mRNA and protein expression in white adipose tissue than control. In conclusion, low dose BPA exposed OLETF rats in adolescent period could accelerate the development of diabetes mellitus in younger adult period.

Light and transmission electron microscopic comparisons of sperms between petrochemical factory workers and public servants in a nonindustrialized area

In this study, we compared the semen characteristics on light microscopy and ultrastructural sperm morphology on transmission electron microscopy between workers in an industrialized area with petrochemical complexes and public servants in a nonindustrialized area. Occupational exposure to petrochemical compounds seems to decrease sperm motility and deteriorate the sperm ultrastructural arrangement, which may lead to this decrease in sperm motility.

An estimate of phthalate exposure among term pregnant women living in Bucheon: The pilot study

목적: 프탈레이트는 프탈산 plasticizers로 사용되는 esters의 한 종류로 국외에서는 많은 연구를 통해 프탈레이트의 노출에 대하여 기술하고 있으나, 우리나라에서는 이와 관련된 연구가 부족한 실정이다. 이에 우리는 만삭 임신부의 소변에서 프탈산의 노출을 평가하였다. 연구방법: 2009년 8월부터 2010년 4월까지 32명의 만삭 분만한 임신부를 대상으로 하였으며, 기관윤리위원회(Institutional Review Board)를 통과하였고, 환경과 식습관에 대하여 질문서와 산과력 및 과거력을 조사하였다. 프탈레이트의 노출을 평가하기 위해서 10가지 phthalate metabolites (mono-methyl phthalate [MMP], mono-ethyl phthalate [MEP], mono-n-butyl phthalate [MnBP], mono benzyl phthalate [MBzP], mono-(2-ethylhexyl) phthalate [MEHP], mono-[2-ethyl-5-hydroxyhexyl] phthalate [MEHHP], mono-(2-ethyl-5-oxohexyl) phthalate [MEOHP], mono-isobutyl phthalate [MiBP], mono-(2-ethyl-5-carboxypentyl) phthalate [5cx-MEPP], and mono-(2- carboxymethylhexyl) phthalate [2cx-MMHP])를 분만 전 24시간 내에 임신부의 소변에서 측정했다. 이들 자료는 예비 실험연구이다. 결과: 임신부들의 평균 나이는 31.1±3.2세, 평균 주수는 38.4±1.3주였다. Creatinine-corrected concentration (geometric mean; μg/g Cr)는 1.754 (MMP), 3.443 (MEP), 3.839 (MnBP), 2.721 (MBzP), 2.437 (MEHP), 4.042 (MEHHP), 3.504 (MEOHP), 2.805 (MiBP), 3.765 (5cx-MEPP), 3.775 (2cx-MMHP)를 나타내었다. 결론: 우리의 데이터는 분만 전 임신부의 소변에서 측정한 프탈레이트의 예비 연구자료로서 본 자료를 토대로 앞으로 다 기관연구 연구에 도움이 될 것으로 보인다.