• Journal of Preventive Medicine and Public Health
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• v.22 no.3 s.27
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• pp.368-379
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• 1989

The relationship between mercury level of hair and mental retardation was investigated. The 297 subjects with mental retardation were drawn from two schools providing special educational services, one, consisted of children living in an orphan home, another, children with parents. The 117 centre] subjects were drawn from whom had got average or above average academic achivement in a regular elementary school. Hair sample were taken from the nape of the neck and the mercury analysis was carried out on an atomic absorption spectrophotometer(IL 551). There was no relationship between mercury contents and age, and there was a statistically significant difference in mercury contents between male and female in the mentally retarded children living with parents. Children in the retarded group had significantly higher mercury contents compared with control group except the female group with parents. Also, the mercury levels in the retarded group living in an orphan home were significantly higher than that of the retarded group with parents. The concomitant diseases were Down's syndrome, epilepsy, cerebral palsy and autism. There were statistically significant differences in hair mercury levels in the cases of accompanying Down's syndrome and cerebral palsy in male and Down's syndrome and autism in female compared with the control group of the same sex. The most accompanying handicap was speech disturbance(40.7%) and the others were crippled, emotional disturbance etc. The percentages of double handicap were 66.7% among 6 persons exceeding 6ppm of their hair mercury contents. 10.4% among $3{\sim}6$ ppm and 15.7% among the group of 3ppm or less. The findings of this study suggest that the more opportunities of exposure to mercury in mentally retarded children may have occurred, so it can not be excluded the possibility of mercury as a contributing factor to mental retardation. Therefore, the causal relationship between mercury levels and mental retardation should be established through the examinations about their living environments, dietary pattern, eating habit etc.

• Journal of Preventive Medicine and Public Health
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• v.39 no.2
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• pp.130-134
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• 2006

Objectives : Oxidative DNA damage is a known risk factor of lung cancer. The glutathione peroxidase (GPX) antioxidant enzyme that reduces hydrogen peroxide and lipid peroxides plays a significant role in protecting cells from the oxidative stress induced by reactive oxygen species. The aim of this case-control study was to investigate effects of oxidative stress and genetic polymorphisms of the GPX1 genes and the interaction between them in the carcinogenesis of lung cancer. Methods : Two hundreds patients with lung cancer and 200 age- and sex-matched controls were enrolled in this study. Every subject was asked to complete a questionnaire concerning their smoking habits and their environmental exposure to PAHs. The genotypes of the GPX1 and 8-oxoguanine glycosylase 1 (hOGG1) genes were examined and the concentrations of urinary hydroxypyrene (1-OHP), 2-naphthol and 8-hydroxydeoxyguanosine (8-OH-dG) were measured. Results : Cigarette smoking was a significant risk factor for lung cancer. The levels of urinary 8-OH-dG were higher in the patients (p<0.001), whereas the urinary 1-OHP and 2-naphthol levels were higher in the controls. The GPX1 codon 198 polymorphism was associated with an increased risk of lung cancer. Individuals carrying the Pro/Leu or Leu/Leu genotype of GPX1 were at a higher risk for lung cancer (adjusted OR=2.29). In addition, these individuals were shown to have high urinary 8-OH-dG concentrations compared to the individuals with the GPX1 Pro/Pro genotype. On the other hand, the polymorphism of the hOGG1 gene did not affect the lung cancer risk and the oxidative DNA damage. Conclusions : These results lead to a conclusion that individuals with the GPX1 Pro/Leu or Leu/Leu genotype would be more susceptible to the lung cancer induced by oxidative stress than those individuals with the Pro/Pro genotype.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.508-517
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• 1997

Hepatitis B virus(HBV) infection is one of the major health problems in Korea and HBsAg positive rate was known to be about $5\sim15%$ in general population. This study was conducted to identify the positive rates of serum HBsAg and anti-HBs among community population regarded as having hish HBV vaccination rate than in previous decade, using EIA(Enzyme immunoassay) method, in Seo-Gu, Taegu, Korea. The study subjects were 1,160 who visited Seo-Gu Health Center for check-up serologic markers of hepatitis 3. The data were obtained from the serologic test for hepatitis markers and questionnaire survey was conducted to obtain the general characteristics, vaccination history, past history of hepatitis and other liver disease, and exposure history to risk factors of hepatitis of the study subjects. The positive rates of HBsAg and anti-HBs were 5.2% and 62.4% respectively. The positive rates of HBsAg for male and female were 6.6% and 4.3% respectively. The age was divided into two groups as group I (less than 15 years old), group II (more than 16 years old) according to the hypothesis that these two groups might be different in HBV vaccination rate. HBV vaccination rates for group I and II were 83.1% and 52.3%. The positive rates of HBsAg for group I and II were 2.6% and 6.5%. The positive rates of HBsAg for the vaccinated people of the group I and II were 2.2% and 3.5%, the positive rates of anti-HBs for the vaccinated people of the group I and II were 70.1% and 71.1% respectively. The most significant factor in positive rate of HBsAg was 'hepatitis carrier in family'. Multiple logistic regression analysis revealed that 'hepatitis history' and 'hepatitis carrier in family' were significant variables for positivity of HBsAg, and 'hepatitis B vaccination' was only a significant variable for positivity of anti-HBs.

• Journal of Life Science
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• v.23 no.2
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• pp.197-206
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• 2013

The present study investigated whether leukemia-maintaining cells reside in a differentiation-resistant fraction using a megakaryocytic differentiation model of K562 cells. Treatment with phorbol-12-myristate-13-acetate (PMA) significantly inhibited the colony-forming efficiency of the K562 cells. At a PMA concentration of 1 nM or higher, colony was not formed, but approximately 40% of K562 cells still survived in soft agar. Approximately 70% of colony-forming cells that were isolated following the removal of PMA after exposure to the agent were differentiated after treatment with 10 nM PMA for 3 days. The differentiation rate of the colony-forming cells was gradually increased and reached about 90% 6 weeks after colony isolation, which was comparable to the level of a PMA-treated K562 control. Meanwhile, imatinib-resistant variants from the K562 cells, including K562/R1, K562/R2, and K562/R3 cells, did not show any colony-forming activity, and most imatinib-resistant variants were CD44 positive. After 4 months of culture in drug-free medium, the surface level of CD44 was decreased in comparison with primary imatinib-resistant variants, and a few colonies were formed from K562/R3 cells. In these cells, Bcr-Abl, which was lost in the imatinib-resistant variants, was re-expressed, and the original phenotypes of the K562 cells were partially recovered. These results suggest that leukemia-maintaining cells might reside in a differentiation-resistant population. Differentiation therapy to eliminate leukemia-maintaining cells could be a successful treatment for leukemia if the leukemia-maintaining cells were exposed to a differentiation inducer for a long time and at a high dose.

• Molecules and Cells
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• v.21 no.1
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• pp.52-62
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• 2006

In previous reports we demonstrated that ginsenosides, active ingredients of Panax ginseng, affect some subsets of voltage-dependent $Ca^{2+}$ channels in neuronal cells expressed in Xenopus laevis oocytes. However, the major component(s) of ginseng that affect cloned $Ca^{2+}$ channel subtypes such as ${\alpha}_{1C}$(L)-, ${\alpha}_{1B}$(N)-, ${\alpha}_{1A}$(P/Q)-, ${\alpha}_{1E}$(R)- and ${\alpha}_{1G}$(T) have not been identified. Here, we used the two-microelectrode voltage clamp technique to characterize the effects of ginsenosides and ginsenoside metabolites on $Ba^{2+}$ currents ($I_{Ba}$) in Xenopus oocytes expressing five different $Ca^{2+}$ channel subtypes. Exposure to ginseng total saponins (GTS) induced voltage-dependent, dose-dependent and reversible inhibition of the five channel subtypes, with particularly strong inhibition of the ${\alpha}_{1G}$-type. Of the various ginsenosides, $Rb_1$, Rc, Re, Rf, $Rg_1$, $Rg_3$, and $Rh_2$, ginsenoside $Rg_3$ also inhibited all five channel subtypes and ginsenoside $Rh_2$ had most effect on the ${\alpha}_{1C}$- and ${\alpha}_{1E}$-type $Ca^{2+}$ channels. Compound K (CK), a protopanaxadiol ginsenoside metabolite, strongly inhibited only the ${\alpha}_{1G}$-type of $Ca^{2+}$ channel, whereas M4, a protopanaxatriol ginsenoside metabolite, had almost no effect on any of the channels. $Rg_3$, $Rh_2$, and CK shifted the steady-state activation curves but not the inactivation curves in the depolarizing direction in the ${\alpha}_{1B}$- and ${\alpha}_{1A}$-types. These results reveal that $Rg_3$, $Rh_2$ and CK are the major inhibitors of $Ca^{2+}$ channels in Panax ginseng, and that they show some $Ca^{2+}$ channel selectivity.

• The Korean Journal of Nuclear Medicine Technology
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• v.24 no.1
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• pp.20-26
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• 2020

Purpose It is intended to figure out the errors derived from changes in depth and volume when measuring the Standard source and ^99mTc-pertechnetate by using a Dose calibrator. Then recommend appropriate measurement depth and volume. Materials and Methods As a Dose calibrator, CRC-15βeta and CRC-15R (Capintec, New Jersey, USA) was used, and the measurement sources were ⁵⁷Co, ¹³³Ba, ¹³⁷Cs and ^99mTc-pertechnetate was also adopted due to its high frequency of use. The Standard source was respectively measured the changes according to its depth without changing the volume, in a range of 0 cm to 15 cm from the bottom of the ion chamber. ^99mTc-pertechnetate was measured at each depth by changing the volume with 0.1 mL, 0.3 mL, 0.5 mL, 0.7 mL and 0.9 mL Respectively. And the depth range was from 0 cm to 15 cm at the bottom of the ion chamber. Results In the case of Standard source ⁵⁷Co, ¹³³Ba, ¹³⁷Cs and ^99mTc-pertechnetate, there were significant differences according to the measurement depth(p<0.05). ^99mTc-pertechnetate has a negative correlation coefficient according to the depth, and the error of the measured value was negligible at a depth from 0 cm to 7 cm at 0.3 mL and 0.5 mL, and the range of error increased as the volume increased. Conclusion In clinical practice, it is sometimes installed differently than the Standard depth recommended by the equipment company. If it's measured at the recommended depth and volume, it could be thought that unnecessary exposure of the operator and the patient will be reduced, and more accurate radiation exams will be possible in quantitative analysis.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.961-967
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• 2005

Macrophage migration inhibitory fartor (MIF), known as a cytokine, is a multifunctional protein that is ubiquitously expressed in a variety of cells and tissues; however, enzymatic function of MIF still remains elusive in cells. In this study, we assessed details of the tautomerase activity of MIF. We established rapid purification condition for MIF by using pGEX system and compared the L-dopachrome tautomerase activity of GST-MIF, tMIF, and MIF. The results show that GST (glutathione S-transferase)-epitope tag or N-terminal amino acids flanking the essential $P^{2}$ almost completely abrogated L-dopachrome tautomerase activity of MIF. Subsequently, to determine whether the N-terminal tags have effects on oligomerization of MIF, protein cross-linking products were analyzed on $15\%$ SDS-PACE. The result demonstrates that N-terminal tags are dispensable for the formation of MIF's homooligomers. Thus, the results imply that exposure of If containing hydrophobic pocket in the active site is critical for L-dopachrome tautomerase activity of MIF. In addition, our study suggest that the MIF's tautomerase activity might be influenced by interacting with cellular partners.

• Korean Journal of Food Science and Technology
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• v.45 no.1
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• pp.97-103
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• 2013

Pine bark extract is made from the bark of Pinus densiflora which naturally contains occurring phytochemicals such as phenolic compounds. PineXol$^{(R)}$ from products of pine bark extract is sold under the brand name. The aim of this study was to evaluate the total phenol, total flavonoids contents and antioxidant activity of the PineXol$^{(R)}$ as well as to assess the lipid accumulation during adipogenesis of 3T3-L1 cells. Our results demonstrate that the total phenolic and flavonoids contents of the PineXol$^{(R)}$ were $717.40{\pm}6.86$ GAE mg/mL and $54.44{\pm}0.01$ RE mg/mL, respectively. The antioxidative activities of the PineXol$^{(R)}$ were significantly increased in a dose dependent manner on DPPH (1,1-Diphenyl-2-picryl hydrazyl) radical scavenging, ABTS (2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) radical scavenging, FRAP (ferric reducing antioxidant power) activity, reducing power, nitrite radical scavenging activity and ORAC (Oxygen radical absorbance capacity) value. In addition, the PineXol$^{(R)}$ inhibited the adipocyte differentiation of 3T3-L1 preadipocytes. Exposure to 200 ${\mu}g/mL$, PineXol$^{(R)}$ significantly reduced lipid accumulation (~80%) in 3T3-L1 cells compared to control cells.

• Korean Journal of Food Science and Technology
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• v.45 no.1
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• pp.59-69
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• 2013

This study investigated the frequency, amount and consumption patterns of 50 potentially hazardous foods (PHF) along with consumers' risk perceptions towards PHF in Korea. A quantitative survey was performed from May through August by trained interviewers, surveying 1,000 adults aged over 18 who were randomly selected from six major provinces in Korea. Consumers perceived seafood, including shellfish, mussel, sashimi and sushi, as the top foods with the highest risk, followed by raw sliced beef. The food with the highest frequency intake per month was leafy vegetables, which is used to wrap other foods, followed by blanched vegetables, fried chicken, etc. The group of middle aged individuals with economic stability had the highest frequency intake of sashimi and sushi. Respondents living in small regions consume greater PHF portions at once. Food safety education with regard to the risk of PHF is essential for consumers, with high frequent intake of PHF.

• Korean Journal of Food Science and Technology
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• v.50 no.1
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• pp.28-36
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• 2018

Studies on suspected endocrine disrupting pesticide (EDP) residues in agricultural products were carried out in 2016 in Busan, Korea. Twelve different EDPs, ranging in concentration between 0.003-2.049 mg/kg, were detected in 19.5% of 462 samples. About 0.2% of agricultural product samples exceeded the maximum residue limits (MRLs). Risk indices of all of the EDPs were less than 10% of the acceptable daily intake (ADI). The outcomes indicated that the risk groups at highest risk of exposure to diazinon (found in Korean cabbages) and carbendazim (found in apples) were females aged 40 to 49 and young males less than 10 years old, respectively. Based on the stochastic assessment at $95^{th}$ percentile (P95), risk index in these risk groups accounted for 8.38 and 2.98% of ADIs. The results showed that the occurrence of EDP residues in agricultural products could not be considered a public health problem.