• Biomolecules & Therapeutics
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• v.15 no.1
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• pp.58-64
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• 2007

The previous study reported the biological effect of magnetic field exerted by acting on endocrine and anti-oxidant system. The present study aims to study whether ELF-MF (extremely low frequency magnetic field) affects the physiological endocrine systems such as thyroid and whether ELF-MF affects the defense system against oxidative stress when it alters the function of thyroid. Finally, we correlate the effects of MF on oxidative stress, and adrenal and thyroid with an environmental stress factor. We exposed sham or MF to rats for 5 or 25 days. After the exposure, we determined pain sensitivity, level of TSH, $T_3$ and free $T_4$ in plasma. We also assayed in whole brain, lipid peroxidation, the activity of enzymatic anti-oxidant defense including superoxide dismutase(SOD) and glutathione peroxidase (GPx), and non enzymatic defense such as reduced or oxidized glutathione contents. MF induced the hypersensitivity to thermal stimuli with the reduction of latency. $T_3$ and $T_4$ levels were also increased by the exposure of MF. In addition, we observed the rise of MDA level in rat brain by MF although the MF did not change superoxide dismutase and glutathione peroxidase activity. The effect of MF on both reduced and oxidized glutathione results in decrease in reduced or oxidized glutathione in whole brain. In every experiment, there was no significant difference in MF influence between short term (5 days) and long term (25 days) exposure. Taken together, MF exposure affects the thyroid hormonal control in brain. The elevated thyroid hormone acts on brain, leading to hyper-utilization of oxygen. This phenomenon may be correlated with oxidative stress resulting from MF exposure. In conclusion, we suggest that MF exposure may be an environmental stress by exerting oxidative stress.

• Journal of Nutrition and Health
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• v.54 no.6
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• pp.644-663
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• 2021

Purpose: This study was conducted to evaluate the safety of iodine intake based on ingestion levels and urinary iodine excretion of women of childbearing age (15-45 years old) using data from the 2013-2015 Korea National Health and Nutrition Examination Survey. Methods: Iodine intake was calculated using the 24 hours dietary recall method and urinary iodine excretion. The iodine nutrition database for the analysis of dietary iodine intake was constructed using the food composition database of the Rural Development Administration (RDA), the Korean Nutrition Society (KNS), the Ministries of Food and Drug Safety, China and, Japan. The World Health Organization (WHO) evaluation criteria and hazard quotient (HQ) calculated using biomonitoring equivalents (BE) were applied to evaluate the safety of the iodine intake. Results: Of the study subjects, 15.22% had a urinary iodine concentration level of less than 100 ㎍/L, which was diagnosed as deficient, and 48.16% had an excessive iodine concentration of over 300 ㎍/L. Urinary iodine concentration was 878.71 ㎍/L, iodine/creatinine was 589.00 ㎍/g, and iodine/creatinine was significantly higher at the age of 30-45 years. The dietary iodine intake was 273.47 ㎍/day, and the iodine intake calculated from the urinary iodine excretion was 1,198.10 ㎍/day. Foods with a high contribution to iodine intake were vegetables, seafood, seaweed and processed foods. The HQ was 1.665 when the urinary iodine content was > 1,000 ㎍/L. Conclusion: The results of this study implicate that the urinary iodine concentration, rather than the dietary iodine intake, is more appropriate to evaluate the iodine status under the current situation that a comprehensive iodine database for Koreans has not been established.

• Clinical and Experimental Pediatrics
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• v.52 no.9
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• pp.991-998
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• 2009

Purpose : Thyroid hormone is essential for development of the brain in early life. Thyroid dysfunction is more common in the first 2-4 postnatal weeks of life in premature infants than in term infants. This study aimed to identify the prevalence and clinical course of thyroid dysfunction in prematurity. Methods : Premature infants admitted to and given neonatal screenings at Dankook University Hospital between April 1999 and March 2008 were included in this study. We retrospectively reviewed medical records and categorized subjects into six groups: normal, hypothyroidism, hyperthyrotropinemia, hypothyroxinemia, delayed onset of hypothyroidism, and delayed onset of hyperthyrotropinemia. Results : Among 599 subjects, 136 (23%) had initially abnormal thyroid function test (TFT); transient hypothyroxinemia was the most frequent condition (118, 20%). In addition, 8 (17%) of 46 subjects with initially normal TFT levels showed delayed onset of hyperthyrotropinemia with or without low free thyroxine ($fT_4$). Thyroxine was prescribed for 10 patients (1.7%) due to low $fT_4$ levels but was discontinued in 9 patients during follow-up. Thyroid scan confirmed ectopic thyroid in one patient. Conclusion : Thyroid dysfunction was frequently seen in premature infants, but most of the conditions were transient. In addition, some infants showed delayed TSH elevation on routine follow-up. Therefore, a recheck of the thyroid function of premature infants at 3-4 weeks is recommended, even if normal thyroid function is initially seen, especially in prematurity of less than 33 weeks of gestational age or birth weight of less than 2,500 grams.

• Archives of Plastic Surgery
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• v.32 no.6
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• pp.699-705
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• 2005

Transgender is the severe type of gender identity disorder. The prevalence rate of transgender is reported to occur to about 1 out of 50,000 men, and about 1 out of 10,000 women. As for Korea, it is estimated to have about 1400 transgender patients. Lately, not only the numbers of them are increasing but also they are influencing our society increasingly. As for female transgender patients, they take female hormone for a long term before and even after the operation to maintain their physical identity of female. We have analyzed insulin like growth factor-1(IGF-1), insulin like growth factor protein binding-3(IGFBP-3), female hormone, male hormone and thyroid hormone in female transgender patients who have undergone the gender reassignment operation. We examined the changes of hormone level due to having female hormone steadily, and also examined how the steady use of the hormone could affect body organs. As for IGF-1, it showed significantly low in the female transgender group compared to control ($319.30{\pm}37.4$ vs $539{\pm}55.0$, p<0.05). As for IGFBP-3, there was no significant difference ($2859{\pm}200.3$ vs $2607{\pm}262.5$, p>0.05). As for female hormone, there was no significant differences in FSH($13.42{\pm}13.8$ vs $8.95{\pm}3.5$, p>0.05), estradiol($104.41{\pm}97.1$ vs $121.68{\pm}60.2$, p>0.05), and LH($7.62{\pm}5.6$ vs $7.4{\pm}3.3$, p>0.05). Even in comparison of testosterone, there was no significant differences($0.23{\pm}0.09$ vs $0.33{\pm}1.33$, p>0.05). As for thyroid hormone, there was no significant differences in TSH and free T4($1.34{\pm}0.94$ vs $1.71{\pm}0.12$, $1.4{\pm}0.37$ vs $1.46{\pm}0.17$, p>0.05). Therefore, this study concludes that apart from the decreased level of IGF-1, the possible endocrine side-effect problem due to female hormone seems to be low because there was no differences of female, male, and thyroid hormone level compared with normal female. Further study will be required in metabolic change including bone metabolism occurred by decrease level of IGF-I.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.133-141
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• 1987

To evaluate the values of the thyroid autoantibody measured by radioimmunoassay (RIA) and compare it with hemagglutination method (HA) in the normal and the thyroid disease, data were obtained from total 618 persons; 236 healthy persons, 217 patients with Graves' disease (including 113 patients with undertreated Graves' disease), 100 Hashimoto's disease, 31 thyroid nodule, and 34 simple goiter. RSR kit made in England was used and could be detected to at least 3 U/ml. The positive rates of normal group were antimicrosomal antibody (AMA) 31.8%, antithyroglobulin antibody (ATA) 44.5% by RIA and there was no considerable change in sex and age distribution. In Graves' disease, the positive rates of AMA and ATA were 90.4, 76.9% by RIA, 85, 39% by HA. In Hashimoto's disease, 94,91 % by RIA, and 87,48% by HA, respectively. The autoantibody titer by RIA in thyroid autoimmune disease as well as in normal group was more senisitive than that by HA, especially in ATA. There were linear relationships between the titer of RIA and that of HA in AMA of Graves' disease and AMA and ATA of Hashimoto's disease. There was no relationship among thyroid autoantibody, free $T_4$ index, TBII, and TSH. The titers of AMA and ATA were found to decrease in patients with Graves' disease during the course of antithyroid drug therapy. Of the 236 normal subjects, thirty-seven (15.7%) had concentrations of above 7.5 U/ml in AMA, forty. four (18.6%) above 9 U/ml in ATA. These values were considered as the upper limit for the normal range. In Graves' disease, 82.7, 53.8% were above 7.5, 9 U/ml, respectively; In Hashimoto's disease, 82, 79% were positive. We conclude that RIA was more sensitve than HA in measuring the thyoird autoantibody, but we will study further more for determining the normal range and its interpretation.

• The Korean Journal of Nuclear Medicine
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• v.12 no.1
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• pp.17-28
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• 1978

A simplified photoelectric apparatus producing graphic records of the free Achilles tendon reflex allowed us to study the reflex quantitatively in subjects with normal and abnormal thyroid function. In this study Achilles tendon reflex times were tested in 340 normal Korean persons, 89 hyperthyroid patients, 19 hypothyroid patients and 85 other thyroid disease patients who were euthyroid in thyroid function tests. In normal Korean persons, the Achilles tendon reflex time was delayed with increasing age and slower in female than in male. They showed good correlationship with various thyroid function tests which included ETR, $T_3RU,\;^{131}I$ thyroid uptake and serum TSH. Diagnostic accuracy of them was 71% in hyperthyroidism and 90% in hypothyroidism. Finally the serial measurements of them were very useful tests in evaluating the clinical coures of hyperthyroidism and hypothyroidism once treatment was begun.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.357-364
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• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$ -subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$-subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t631 or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632~653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agoinst-occupied receptors ~2- and ~17- fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.