Ki Hyun Baek

Catholic University of Korea, Sŏul, Seoul, South Korea

Are you Ki Hyun Baek?

Claim your profile

Publications (42)100.11 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, we evaluated the association between bone mineral density (BMD) and 10 single-nucleotide polymorphisms (SNPs) within eight osteoporosis susceptibility genes that were previously identified in genome-wide association studies (GWASs). A total of 494 men and 493 postmenopausal women participating in the Chungju Metabolic Disease cohort study in Korea were included. The following 10 SNPs were genotyped: ZBTB40 rs6426749, MEF2C rs1366594, ESR1 rs2941740, TNFRSF11B rs3134070, TNFRSF11B rs2073617, SOX6 rs711785, LRP5 rs599083, TNFSF11 rs227438, TNFSF11 rs9594782, and FOXL1 rs10048146; and the association between these SNPs and bone metabolism-related markers was assessed. Two SNPs, TNFSF11 rs2277438 and FOXL1 rs1004816, were associated with lumbar spine BMD. TNFSF11 rs2277438 in men and SOX6 rs7117858 and FOXL1 rs10048146 in postmenopausal women were found to be associated with lumbar BMD. ZBTB40 rs6426749, MEF2C rs1366594, and LRP5 rs599083 showed significant associations with femur neck BMD. These three SNPs in men and MEF2C rs1366594 and ESR1 rs2941740 in postmenopausal women were associated with femur neck BMD. A significant association between MEF2C rs1366594 and serum calcium levels was observed in men. Serum phosphorus levels were related to SOX6 rs7117858. Serum PTH levels were significantly associated with TNFRSF11B rs3134070 in men, and SOX6 rs711858 in postmenopausal women. In conclusion, our study independently confirmed associations between several SNPs: ZBTB40, MEF2C, ESR1, SOX6, LRP5, TNFSF11, and FOXL1 and bone marrow density in the Korean population.
    Endocrine journal. 08/2014;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Aims/IntroductionLittle is known about the long-term effects of Roux-en-Y gastric bypass (RYGB) in severely obese Asian individuals.Methods and MaterialsA total of 33 severely obese patients with type 2 diabetes underwent RYGB. All patients were followed up for 2 years. Visceral and abdominal subcutaneous fat areas were assessed using computed tomography (CT) before, and 12 and 24 months after RYGB. The muscle attenuation (MA) of paraspinous muscles observed by CT were used as indices of intramuscular fat.ResultsThe mean percentage weight loss was 22.2 ± 5.3% at 12 months, and 21.3 ± 5.1% at 24 months after surgery. Compared with the baseline values, the visceral fat area was 53.6 ± 17.1% lower 24 months after surgery, and the abdominal subcutaneous fat area was 32.7 ± 16.1% lower 24 months after surgery. The MA increased from 48.7 ± 10.0 at baseline to 52.2 ± 8.9 (P = 0.009) 12 months after surgery. The MA after the first 12 months maintained changes until 24 months. Triglycerides and free fatty acids were reduced after surgery, whereas the high-density lipoprotein cholesterol levels were increased significantly after surgery. At the last follow-up visit, 18 patients (55%) had diabetes remission. The percentage of iron and vitamin D deficiency was 30% and 52%, respectively.Conclusions We found that patients subjected to RYGB had significant sustained reductions in visceral and intramuscular fat. There were durable improvements in the cardiometabolic abnormalities without any significant comorbidities. However, there were mild nutritional deficiencies in these patients despite daily supplementation with multivitamins and minerals.
    Journal of Diabetes Investigation. 03/2014; 5(2).
  • Source
    Dong Jun Lim, Ki Hyun Baek
    Endocrinology and metabolism (Seoul, Korea). 09/2013; 28(3):243-4.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The natural course of cytologically benign thyroid nodules remains unclear. The aim of this study was to evaluate whether ultrasonographic (US) changes are associated with changes in nodule volume during follow-up. We retrospectively reviewed over 4 years of clinical records of patients with benign thyroid nodules as confirmed by fine needle aspiration (FNA). In total, 186 patients with 202 benign thyroid nodules were included for study. We assessed for changes in nodule volume and examined the cystic portion of the nodule as well as four US features (echogenicity, margin, calcification pattern, and shape). During follow-up (mean, 21.7±10.7 months) and using 50% as a cutoff value, nodule volumes increased in 11.8%, exhibited no change in 79.9%, and decreased in 8.3% of patients. Proportion of nodules demonstrating at least one US change was 20.8% (42/202). The most common US changes (in descending order of frequency) were cystic change, margin change, and calcification pattern change. Nodule shape and echogenicity rarely changed. Increased nodule volume was not significantly associated with any US features or with the number of FNAs but was associated with younger age at time of diagnosis. Although a portion of thyroid nodules confirmed as benign showed US changes or volume changes during the follow-up period, these findings may only represent the natural course of benign nodules. Frequent follow-up with US might be needed for only a small number of cases with suspicious US findings.
    Endocrinology and metabolism (Seoul, Korea). 06/2013; 28(2):110-8.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: 2-[18F]Fluoro-2-D-deoxyglucose (FDG)-positron emission tomography (PET) computed tomography (CT), which can detect a change in glucose metabolism in cancer cells, has been introduced as a diagnostic and prognostic tool in papillary thyroid carcinoma (PTC). However, differences in the clinicopathological and biological characteristics between primary PTCs with FDG uptake and those whithout FDG uptake are not well established. Methods: A total of 188 patients with PTC who had preoperative PET/CT scans were enrolled to compare the differences of clinicopathological parameters between FDG-avid (F-PTC) (n=150) and FDG-non-avid tumors (FN-PTC) (n=38). Immunohistochemical staining for glucose transporter (GLUT)-1 and hypoxia-inducible factor-1 alpha (HIF-1α) was performed. Results: FN-PTCs were smaller, had a lower incidence of lymphatic invasion, vascular invasion, multiplicity, and central lymph node metastasis, and had a lower maximum standardized uptake value than F-PTCs. After exclusion of high-risk patients for recurrence, FN-PTCs remained smaller (P<0.001) and had less lymphatic invasion (P=0.061). Among tumors larger than the spatial resolution of the PET/CT scan, macrocalcification was more frequent in FN-PTC than in F-PTC (P=0.043). While FN-PTC and F-PTC showed no difference in GLUT-1 expression (50% vs. 75%, P=0.363), FN-PTC showed lower immunoreactivity of HIF-1α than F-PTC (25.0% vs. 75.0%, P=0.032). Conclusion: Tumor size and macrocalcification are clinicopathological differences between FN-PTC and F-PTC. Biologically, HIF-1α may be responsible for increased FDG uptake in PTC.
    Thyroid: official journal of the American Thyroid Association 05/2013; · 2.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recent studies suggest an association of vitamin D with obesity, diabetes and cardiovascular diseases. We analyzed the association of serum vitamin D level assessed by 25-hydroxyvitamin D(3) {25(OH)D(3)} with nonalcoholic fatty liver disease (NAFLD) in apparently healthy men. We performed a cross-sectional study of 6,567 Korean men who participated in a health screening program, evaluating the association of serum 25(OH)D(3) levels with the risk of NAFLD assessed by abdominal ultrasonogram. Of the participants, 43.6% had NAFLD and 21.1% had metabolic syndrome. Age, serum calcium, and aspartate aminotransferase levels showed weak but significant positive correlations with 25(OH)D(3) level; total cholesterol, triglycerides, low-density lipoprotein cholesterol and fasting insulin level showed weak but significant negative correlations with 25(OH)D(3) level. The mean 25(OH)D(3) level was significantly lower in participants with NAFLD than in those without (38.7 ± 9.0 vs. 39.7 ± 9.7 nmol/L, p < 0.001). When participants were divided into tertiles based on mean 25(OH)D(3) level, the proportion with NAFLD significantly increased as mean 25(OH)D(3) level decreased (40.0, 45.0 and 45.9%, p for linear trend < 0.001). Multiple logistic regression analyses with NAFLD as the dependent variable showed that the tertiles with lower 25(OH)D(3) levels had a significantly increased risk for NAFLD compared with the highest tertile, even after adjusting for body mass index and metabolic syndrome (OR 1.247 and 1.408 vs. the highest tertile, p < 0.001). Thus, participants with higher serum 25(OH)D(3) showed a significantly reduced risk for NAFLD compared with the low 25(OH)D(3) groups, independent of obesity and metabolic syndrome.
    Endocrine Journal 02/2013; · 2.23 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recent data suggest that variations in calcium intake may influence body weight and composition; however, the relationship between daily calcium intake and muscle mass has not been well established. The objective of this study was to assess the relationship between daily calcium intake and sarcopenia. We analyzed data for older adults (over 60 years) from the fourth Korea National Health and Nutrition Examination Survey (KNHANES) conducted in 2009. A total of 1339 Non-Obese (BMI between 18.5 and 25 kg/m(2)), older adults (592 men and 707 women) were enrolled. Dietary variables were assessed using a nutrition survey that used a 24-hour recall method. Daily calcium intake based on the consumption of each food item was calculated. Sarcopenia was defined as an appendicular skeletal muscle mass divided by body weight less than 2 SD below the sex-specific mean for young adults. We found that daily calcium intake was negatively correlated with total body fat percentage and positively correlated with appendicular skeletal mass (p<0.001). Participants with sarcopenia appear to have significantly lower daily calcium intakes than participants without sarcopenia (p<0.001). The unadjusted prevalence of sarcopenia according to daily calcium intake tertiles were 6.3%, 4.3%, and 2.7% in tertiles 1, 2, and 3, respectively. After adjustment for age, sex, BMI, total energy intake, and lifestyle factors, compared with those in the lowest tertile of daily calcium intake, participants in the highest tertile had an odds ratio for sarcopenia of 0.295 (95% confidence interval, 0.087-0.768; p for trend = 0.014). We found that daily calcium intake, corrected for total energy intake and serum 25(OH)D status, was significantly lower in subjects with sarcopenia than in those without. Our results suggest a strong inverse association between daily calcium intake and sarcopenia in non-obese, older Korean adults.
    Endocrine Journal 01/2013; · 2.23 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Some papers have suggested that alkaline phosphatase (ALP) level is a predictor of the metabolic syndrome (MetS) in the general population. However, the association is still controversial, and the mechanisms underlying an association between ALP level and the MetS have not been elucidated. We analyzed the association between serum ALP level and the development of the MetS over a 4-year period. A total of 14,224 subjects who visited the Health Promotion Center for a medical examination in 2005 were followed up after 4 years. Serum ALP level correlated positively with body fat mass and visceral fat mass. The adjusted geometric mean ALP levels were higher in subjects with elevated C-reactive protein level or greater fat mass (P < 0.001). None of the subjects had the MetS at baseline, but 1,179 exhibited the MetS at the 4-year follow-up. After multiple adjustments, the odds ratio (OR) was substantially higher for development of the MetS (OR 1.56, 95% confidence intervals, 1.21-2.01) in subjects in the highest ALP quintile compared with those in the lowest quintile. After adjusting for various covariates, we found significant associations between the quintile of serum ALP level and abdominal obesity, low high-density lipoprotein cholesterol level, and high triglyceride level. Higher serum ALP level was a significant predictor of the MetS in middle-aged Koreans. Serum ALP level correlated positively with body fat mass and independently with a more atherogenic lipid profile in the general population in Korea.
    Endocrine Journal 11/2012; · 2.23 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Galectin-3 (G3) immunostaining of fine-needle aspiration (FNA) samples from thyroid nodules is very useful for the diagnosis of malignancy. The objective of the present study was to determine whether the absence of G3 immunostaining in preoperative FNA samples is associated with favorable clinicopathological parameters, including lymph node (LN) metastasis, in papillary thyroid carcinoma (PTC). Methods: The records of 868 patients with PTC who had prethyroidectomy ultrasonography-guided FNA with G3 immunostaining between January 2006 and December 2009 were retrospectively reviewed. G3 immunostaining was considered positive if the percentage of tumor cells showing definite cytoplasmic immunostaining exceeded 5%. Patients who had negative G3 immunostaining of FNA samples were assigned to the G3-negative (G3N) group; whereas those who had positive G3 immunostaining were assigned to the G3-positive (G3P) group. Results: There were 92 patients who were assigned to the G3N group (10.6%) because of the negative staining for G3 in the preoperative FNA samples from their thyroid nodules. The proportion of PTC subtypes in the G3N and G3P groups was similar (p=0.376). There was less frequent thyroid capsular invasion (46.7% vs. 66.5%, p<0.001), extrathyroidal extension (28.3% vs. 48.5%, p<0.001), and LN metastasis (22.2% vs. 48.7%, p<0.001) in the G3N group than the G3P group. In multivariate regression analysis, G3N expression predicted a lower risk of LN metastasis (odds ratio=0.37, 95% confidence interval 0.18-0.78) after adjustment for other clinicopathological parameters. Over a median follow-up of 33 months, no association was observed between G3N and disease-free survival. Conclusion: The absence of G3 expression in FNA samples from PTC is associated with pathological parameters considered less aggressive than is the case for PTCs with G3 expression, including being a negative predictor of negative LN involvement. Long-term follow-up studies, however, are needed to verify whether G3N patients have lower recurrence and mortality rates.
    Thyroid: official journal of the American Thyroid Association 08/2012; · 2.60 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to investigate the influences of visceral adiposity on cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes mellitus. Two hundred eleven patients with type 2 diabetes participated in this study. Anthropometric and metabolic parameters were measured, and the visceral fat area was assessed using computed tomography. CAN was diagnosed using a cardiovascular reflex test. We analyzed the correlation between the visceral fat area and each parameter in this test. The mean age, body mass index (BMI), and duration of diabetes of the study population were 60±14 years (mean±standard deviation), 25.1±4.2 kg/m(2), and 12.3±8.9 years, respectively. The visceral fat area showed positive correlations with age, BMI, waist circumference, and subcutaneous fat area. There was no statistically significant difference in the cardiovascular reflex test outcome between genders. Univariate linear regression analysis showed that an increased visceral fat area diminished good heart rate response to a Valsalva maneuver (R(2)=4.9%, P=0.013 in an unadjusted model), but only in women. This statistical association was preserved after adjusting for age and BMI (R(2)=9.8%, P=0.0072). The results of this study suggest that visceral adiposity contributes to an autonomic imbalance to some degree, as demonstrated by the impaired cardiovascular reflex test among women with type 2 diabetes.
    Diabetes & metabolism journal 08/2012; 36(4):285-92.
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Transfusional iron overload primarily results in reticuloendothelial iron accumulation, which is considered to be less harmful than parenchymal iron accumulation. However, systematic and comprehensive data on endocrine function in transfusion-associated hemochromatosis are limited. METHODS: We examined 25 aplastic anemia patients (11 men and 14 women) diagnosed with transfusion-associated hemochromatosis at a single institution. Pituitary function was determined with a combined pituitary function test. On a different day, a 75 g oral glucose tolerance test was performed. The bone mineral density (BMD) of the lumbar spine and total hip was assessed with dual-energy X-ray absorptiometry. RESULTS: Twenty-two (88%) of these 25 patients had at least one endocrine abnormality, and 12 had more than one abnormality. The most common pituitary hormonal deficiency involved the pituitary-gonadal axis; 54% of the total subjects had hypogonadotropic hypogonadism. Two patients had an insufficient cortisol response to corticotropin-releasing hormone stimulation. No patient had a deficiency of growth hormone or thyroid-stimulating hormone. Twelve (48%) had diabetes mellitus and these patients tended to have higher concentrations of ferritin, alanine aminotransferase, and γ-glutamyl transferase. Osteoporosis (T-score < -2.5 SD) was observed in 48% of patients. The reduction in BMD was more pronounced in the lumbar spine than in the total hip. The patients with osteoporosis were accompanied by hypogonadism, which predominantly affected the trabecular bone. CONCLUSIONS: Our observations suggest that endocrinopathies are common in transfusion-associated hemochromatosis. © 2012 Blackwell Publishing Ltd.
    Clinical Endocrinology 07/2012; · 3.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We prospectively examined the association between type 2 diabetes mellitus (T2DM) progression and common T2DM-risk gene variants in 870 non-diabetic participants in a Chungju Metabolic Disease Cohort Study in Korea. We genotyped the following six single nucleotide polymorphisms (SNPs): KCNQ1 (potassium voltage-gated channel, KQT-like subfamily member 1) rs2237892, CDKAL1 (regulatory subunit-associated protein 1-like 1) rs7554840, CDKN2A/B (cyclin-dependent kinase inhibitor 2A/B) rs1081161, SCL30A8 (solute carrier family 30 member 8 gene) rs13266634, TCF7L2 (transcription factor 7-like 2) rs7903146, and PPARG (peroxisome proliferator activated receptor gamma) rs1801282. Anthropometric data and metabolic parameters were obtained at baseline and year 4. Pancreatic β cell function was assessed by the homeostasis model assessment index of β cells (HOMA-β). After 4 years, 137 subjects developed T2DM (15.7%). A significant association was found in the variant of KCNQ1 rs2237892, whereas the SNPs of CDKAL1, CDKN2A/B, SCL30A8, TCF7L2 and PPARG were not associated. The C-allele carriers of KCNQ1 conferred a significantly increased risk for T2DM compared with the T/T genotype, independently of clinical risk factors (odds ratio=2.61, 95% confidence intervals=1.02-6.69, P=0.04). Although no differences were observed at baseline among the KCNQ1 variants, HOMA-β levels by year 4 were significantly lower in the C-allele carriers after controlling for metabolic parameters. The genetic variations in KCNQ1 are associated with future development of T2DM in Koreans, which might be mediated by differences in insulin secretory function.
    Journal of Human Genetics 03/2012; 57(4):265-8. · 2.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We aimed to examine the relationship between iron status and hypertension as few studies have addressed this. We analyzed the association between ferritin/total iron-binding capacity (TIBC) and the subsequent development of hypertension. A total of 8,580 men who visited the Health Promotion Center for a medical checkup in 2005 were followed-up after 4 years. Of the 8,580 men who were not hypertensive at baseline, 818 were found to be hypertensive at the 4-year follow-up. Compared with those who remained normotensive, these hypertensive subjects had higher levels of ferritin and TIBC at baseline, but had no significant difference in iron levels. After adjustment for age and body mass index (BMI), the odds ratios (OR) was substantially higher for new hypertension (OR 1.54, 95% confidence intervals (CIs) 1.26-1.88; P for trend <0.001) in subjects with the highest ferritin quartiles compared with those in the lowest quartiles. The association of serum ferritin levels with the incidence of hypertension was unchanged after adjustment for baseline blood pressure (BP). Adjustment for insulin resistance as measured by the homeostasis model assessment and the presence of a fatty liver reduced the magnitude of the OR for hypertension (first quartile reference, fourth quartiles OR 1.24, 95% CI 1.01-1.53, P for trend = 0.012), but did not affect their statistical significance. Serum ferritin, but not iron level, was a significant predictor of hypertension in middle-aged Korean men. Fatty liver disease and insulin resistance may be mediators of this high ferritin-hypertension association.
    American Journal of Hypertension 01/2012; 25(4):492-7. · 3.67 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An association between vitamin D status and sarcopenia has not been shown in a community-dwelling cohort, despite the well-documented relationship between vitamin D status and falls. Our objective was to investigate whether vitamin D level is associated with sarcopenia in older Koreans. The Fourth Korea National Health and Nutrition Examination Survey in the Korean population was conducted in 2009. Participants included 1380 men and 1789 women aged 50 yr or older. Serum 25-hydroxyvitamin D [25(OH)D] and PTH levels were measured. Sarcopenia was defined as an appendicular skeletal muscle mass divided by body weight that was less than 2 sd below the sex-specific mean for young adults. Obesity was defined as a body mass index (BMI) of 27.5 kg/m(2) or higher. 25(OH)D level correlated negatively with appendicular fat mass and positively with appendicular skeletal mass. The groups with sarcopenic obesity and sarcopenia only had lower 25(OH)D levels than did the nonsarcopenia groups. However, 25(OH)D levels did not differ between the sarcopenic obesity and sarcopenia groups. After adjustment for age, sex, BMI, and lifestyle factors, compared with those in the lowest quartile of 25(OH)D level, participants in the highest quartile had an odds ratio for sarcopenia of 0.47 (95% confidence interval = 0.30-0.73; P for trend = 0.001). There was no association between PTH and sarcopenia after adjustment of BMI. Vitamin D levels were significantly lower in subjects with sarcopenia than in those without, regardless of obesity. We found a strong inverse association between 25(OH)D level and sarcopenia in the older Korean population.
    The Journal of Clinical Endocrinology and Metabolism 08/2011; 96(10):3250-6. · 6.31 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The present study was designed to develop criteria for screening patients with type 2 diabetes mellitus (T2DM) for asymptomatic coronary artery disease (CAD). A total of 213 patients with T2DM without typical angina or chest pain were studied between 2002 and 2007. We also evaluated 53 patients with T2DM who had reported chest discomfort using an exercise treadmill test (ETT). Thirty-one of the 213 asymptomatic patients had positive ETT results. We performed coronary angiography on 23 of the 31 patients with a positive ETT and found that 11 of them had significant coronary stenosis. The main differences between the patients with significant stenosis and those with a negative ETT were age (63.1±9.4 vs. 53.7±10.1 years, P=0.008) and duration of diabetes (16.0±7.5 vs. 5.5±5.7 years, P<0.001). The positive predictive value (PPV) of the ETT was calculated to be 47.8%. The PPV of the ETT increased to 87.5% in elderly patients (≥60 years) with a long duration of diabetes (≥10 years). The latter value is similar to that of patients with T2DM who presented with chest discomfort or exertional dyspnea. The PPV of the ETT in symptomatic patients was 76.9%. In the interest of cost-effectiveness, screening for asymptomatic CAD could be limited to elderly patients with a duration of diabetes ≥10 years.
    Diabetes & metabolism journal 02/2011; 35(1):34-40.
  • [Show abstract] [Hide abstract]
    ABSTRACT: To clarify the association of serum calcium level with metabolic syndrome (MetS) and diabetes in middle-aged and elderly Korean subjects. We conducted a population-based, cross-sectional survey of 1329 participants aged over 40 years (median age 65.8) in a rural area of Chungju, Korea, in 2007. Serum level of albumin, calcium, 25-hydroxy-vitamin D and intact parathyroid hormone were measured in a central laboratory. The prevalence of MetS increased progressively with elevated serum albumin-corrected calcium levels (P<0.001 for trend). After adjusting for various covariates, subjects in the highest quintile group (2.45-2.99 mmol/L) compared with the lowest quintile group (2.05-2.24 mmol/L) of serum calcium levels had an odds ratio (OR) for having MetS of 3.11 (95% confidence intervals, CI, 1.95-4.97; P for trend<0.001). Excluding the subjects with hypocalcemia and hypercalcemia (n=1064) did not alter this significant association. After multiple adjustment, subjects with serum calcium levels in the fourth to fifth quintiles had a 2.0- to 3.0-fold increased OR of having diabetes (first quintile reference, fourth quintiles OR 2.38; 95% CI 1.32-4.28, fifth quintiles OR 3.32; 95% CI 1.87-5.88; P for trend<0.001).The associations of serum calcium levels with the incidences of MetS or diabetes were unchanged after adjustment for 25(OH)D and PTH levels. Altered calcium homeostasis was associated with an increased risk of having MetS and diabetes in this demographic group.
    Atherosclerosis 10/2010; 212(2):674-81. · 3.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: It has been suggested that oxidative stress is associated with the pathogenesis of osteoporosis. The objective of this study was to explore the association between a marker of oxidative stress and either bone turnover markers or bone mineral density (BMD) in postmenopausal women. In addition, the effects of oxidative stress on the formation of osteoclasts in human bone marrow cell culture were examined. We performed a cross-sectional analysis in healthy postmenopausal women aged 60-78 years (n = 135, 68.2 +/- 4.9). Oxidative stress was evaluated in the serum by measuring 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels. The biochemical markers of bone turnover and areal BMD were measured in all participants. Multivariate linear regression analysis revealed a negative association between 8-OH-dG levels and BMD of the lumbar spine, total hip, femoral neck, and trochanter and positive association with type I collagen C-telopeptide (ICTP) levels. The odds ratio of 8-OH-dG for osteoporosis was 1.54 (1.14-2.31, P = 0.003). In cultures of primary human marrow cells, H2O2 caused concentration-dependent activation of TRAP-positive multinucleated giant cells. H2O2 also increased the area of pits per osteoclast activity assay substrate. RT-PCR showed that H2O2 stimulated the expression of M-CSF and RANKL and increased the RANKL/OPG ratio. The data support the view that oxidative stress is associated with increased bone resorption and low bone mass in otherwise healthy women. In addition, RANKL and M-CSF stimulation induced by oxidative stress may participate in osteoclastogenesis in human bone.
    Calcified Tissue International 09/2010; 87(3):226-35. · 2.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The association between autoimmune thyroiditis (AIT) and thyroid cancer is still not clear despite many previous reports. This study investigated whether serologic thyroid antibodies are predictive of thyroid cancer in patients with thyroid nodules. We retrospectively reviewed records of patients with thyroid nodules evaluated by ultrasonography-guided fine-needle aspiration cytology at our institution between January 2006 and December 2008. Thyroid autoimmunity was assessed by measuring thyroglobulin antibody (TgAb) and thyroid peroxidase antibody (TPOAb). The final outcome deciding a benign or malignant status involved a combination of cytology and histology. Of the 1638 patients, malignant nodules had a higher rate of positive TgAb (30.8% vs. 19.6%; p < 0.001) and elevated thyrotropin (TSH) levels (2.5 +/- 2.8 mIU/L vs. 2.1 +/- 2.0 mIU/L; p = 0.021) than benign nodules. The rate of positive TPOAb was not higher in malignant nodules, although both TPOAb and TgAb were well correlated with TSH levels and histological AIT. In the multivariate analysis, a positive TgAb was significantly associated with thyroid cancer (odds ratio [OR] = 1.61, 95% confidence interval [CI] 1.12-2.33) with upper tertile of normal range of TSH levels (OR = 1.72, 95% CI 1.12-2.63) and above normal range of TSH levels (OR = 1.98, 95% CI 1.06-3.70). We report for the first time that a positive serum TgAb test was an independent predictor for thyroid malignancy in thyroid nodules along with serum TSH levels regardless of the presence of AIT. Our results suggest that TgAb measurement could give additional information for predicting malignancy in cytologically indeterminate thyroid nodules in conjunction with clinical risk factors and TSH levels.
    Thyroid: official journal of the American Thyroid Association 05/2010; 20(8):885-91. · 2.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 64-year-old woman was biochemically diagnosed with hyperparathyroidism. Technetium-99m sestamibi parathyroid scan demonstrated persistent uptake in the left lower pole of the thyroid. She underwent F-18 FDG PET due to unrelated causes. Incidentally, we found focal FDG accumulation in the lower portion of left thyroid lobe. An ultrasound showed a 2.2-cm nodule containing cystic component in the left lower pole of the thyroid. The intact PTH level in the cystic fluid was much higher than the serum intact PTH level, suggesting an intrathyroidal parathyroid adenoma. Left lobectomy revealed an intrathyroidal parathyroid adenoma in the left thyroid lobe.
    Clinical nuclear medicine 04/2009; 34(3):178-9. · 3.92 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We aim to investigate erythropoietin (EPO) response to anemia and its association with autonomic neuropathy in type 2 diabetic patients without advanced renal failure. A cross-sectional study was conducted on 211 type 2 diabetes mellitus patients without advanced renal failure [estimated glomerular filtration rate (eGFR) >40 ml/min/1.73 m(2)]. The response of EPO to anemia of type 2 diabetic patients without advanced renal failure was compared with those of nondiabetic control subjects. Autonomic nerve function was assessed using three cardiovascular tests (deep breathing, the Valsalva maneuver, and lying-to-standing). The results of each test were scored as 0 if normal, 1 if borderline, and 2 if abnormal. Autonomic neuropathy was diagnosed when a total score of the tests was 2 or more. Fifty-eight patients were anemic; compared with nonanemic patients, they had a longer duration of diabetes (16.69+/-10.11 vs. 10.67+/-8.41 years, P<.001), lower eGFR (66.43+/-16.30 vs. 81.74+/-19.49 ml/min/1.73 m(2), P<.001), and higher cardiovascular autonomic neuropathy score (3.17+/-1.95 vs. 1.79+/-1.72, P<.001). Serum EPO level was weakly correlated with hemoglobin (Hb) level (r=-.085, P<.001). However, the slopes of regression lines between EPO and Hb levels differed significantly between type 2 diabetic patients and nondiabetic control subjects (-0.0085 vs. -0.255, P=.008). Multiple linear regression analysis revealed that cardiovascular autonomic neuropathy score was independently related to Hb (P<.001) or EPO level (P=.052). Autonomic neuropathy is associated with a blunted EPO response to anemia in type 2 diabetic patients without advanced renal failure.
    Journal of diabetes and its complications 03/2009; 24(2):90-5. · 2.11 Impact Factor

Publication Stats

502 Citations
100.11 Total Impact Points

Institutions

  • 2004–2014
    • Catholic University of Korea
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2002–2013
    • Kangbuk Samsung Hospital
      Sŏul, Seoul, South Korea
  • 2006
    • Sungkyunkwan University
      • Department of Internal Medicine
      Seoul, Seoul, South Korea
  • 2004–2005
    • Hallym University
      • College of Medicine
      Seoul, Seoul, South Korea