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Featured researches published by Ohk Hyun Ryu.


Diabetes Research and Clinical Practice | 2008

Use of a real time continuous glucose monitoring system as a motivational device for poorly controlled type 2 diabetes.

Hye Jin Yoo; Hyonggin An; Soyeon Park; Ohk Hyun Ryu; Honggon Kim; J.A. Seo; Eun-Gyoung Hong; D.H. Shin; Y.H. Kim; Suhyun Kim; Kyung Mook Choi; Inkeun Park; Jae Myung Yu; S. H. Baik

OBJECTIVE The use of a real time continuous glucose monitoring system (RT-CGM) was studied as a behavior modification tool and the effectiveness of a RT-CGM in glucose control for patients with type 2 diabetes was determined. METHODS We conducted a prospective, open-label, randomized, controlled clinical trial in 65 patients with poorly controlled type 2 diabetes (8.0</=HbA1c</=10%) over a 3-month period. The intervention group was monitored monthly with a RT-CGM (three days at a time for 3 months) and the control group continued self-monitoring blood glucose (SMBG) at least four times a week for 3 months. RESULTS The HbA1c of the RT-CGM group was significantly reduced after 12 weeks compared with the SMBG group (9.1+/-1.0% to 8.0+/-1.2% vs. 8.7+/-0.7% to 8.3+/-1.1%, respectively; P=0.004). In the RT-CGM group, there was a significant reduction in total daily calorie intake, weight, body mass index (BMI), and postprandial glucose level, and a significant increase in total exercise time per week after 3 months. CONCLUSIONS We demonstrated that the RT-CGM was useful in modifying a patients diet and exercise habits and could induce better glycemic control than SMBG for patients with type 2 diabetes.


Clinical Endocrinology | 2005

Serum osteoprotegerin levels are associated with inflammation and pulse wave velocity

Sin-Gon Kim; Jung-Suk Lee; Ohk Hyun Ryu; Kwangyeol Lee; Honggon Kim; J.A. Seo; Sin Gon Kim; N.H. Kim; S. H. Baik; Dong Seop Choi; Kyung Mook Choi

Objective  We examined the association between serum osteoprotegerin (OPG) levels, systemic inflammation and arterial stiffness in normal and diabetic patients.


Clinical Endocrinology | 2008

Serum retinol-binding protein 4 levels are elevated in non-alcoholic fatty liver disease

J.A. Seo; N.H. Kim; So Yeon Park; Honggon Kim; Ohk Hyun Ryu; Kwangyeol Lee; Jung-Suk Lee; Dong-Lim Kim; Kyung Mook Choi; S. H. Baik; D. S. Choi; Suhyun Kim

Objective  Retinol‐binding protein 4 (RBP4) is a recently identified adipokine that is elevated in the serum in several insulin‐resistant states. We investigated the relationship between non‐alcoholic fatty liver disease (NAFLD) and serum RBP4 in nondiabetic adults.


Proteomics Clinical Applications | 2007

The discovery of biomarkers for type 2 diabetic nephropathy by serum proteome analysis.

Eun Hee Cho; Mi Ryung Kim; Hyun Jung Kim; Do Yeon Lee; Pan Kyeom Kim; Kyung Mook Choi; Ohk Hyun Ryu; Chan W. Kim

Diabetic nephropathy (DN) is a serious kidney complication of diabetes, and constitutes the leading cause of end‐stage renal disease. The earliest clinical evidence of DN is microalbuminuria, a term which refers to the appearance of small but abnormal amounts of albumin in the urine. However, screening methods for DN, such as biomarker assays, are yet to be developed for type 2 DN. In the present study, in an attempt to identify the biomarkers for initial diagnoses of type 2 DN, the protein profiles of human sera collected from 30 microalbuminuric type 2 diabetic patients were compared with those collected from 30 normoalbuminuric type 2 diabetic patients, via 2‐DE. As a result, a total of 18 spots were determined to have different protein levels in the microalbuminuric patients. Twelve spots had lower protein levels of approximately 50%, and the other six had higher levels of approximately 100–300% as compared to the spots of normoalbuminuric patients. These spots were identified with ESI‐Q‐TOF (ESI‐quadrupole‐TOF) MS. Among the identified proteins, vitamin D‐binding protein (DBP) and pigment epithelium‐derived factor (PEDF) were verified by Western blotting. The results of this study indicate that the DBP may be employed as diagnostic and monitoring biomarkers of type 2 DN, contingent on further study into the matter.


European Journal of Endocrinology | 2009

The relationship of thyroid hormone status with myocardial function in stress cardiomyopathy

Seong Jin Lee; Jun Goo Kang; Ohk Hyun Ryu; Chul Sik Kim; Sung-Hee Ihm; Moon Gi Choi; Hyung Joon Yoo; Kyung Soon Hong

OBJECTIVE This study aimed to investigate thyroid hormone (TH) status and its relationship with myocardial function as well as clinical and biochemical parameters in stress cardiomyopathy (CMP). METHODS Forty-five patients with stress CMP (the patient group), 31 patients without stress CMP (the control II group), and 58 healthy subjects (the control I group) were included. Sick euthyroid syndrome (SES) was defined as low total triiodothyronine (T(3)) with normal TSH levels. RESULTS In the patient group at admission, prevalence of SES was 62.2%. Compared with the control I group, the patient group had a decrease in left ventricular ejection fraction (LVEF) and systolic blood pressure (BP) and an increase in troponin-I, CK-MB, and B-type natriuretic peptide (BNP) levels. Total T(3) levels were reduced, and anti-thyroid peroxidase antibody (anti-TPO Ab) positivity, C-reactive protein (CRP) and cortisol levels were elevated. Total T(3) levels were associated with acute physiology and chronic health evaluation II (APACHE II) score, LVEF, systolic BP, and cortisol levels in multivariate analysis. In the control II group, total T(3) levels were not associated with any variables. In the SES (n=28) and myocardial dysfunction (MDys, n=27) subgroups, increased APACHE II score and BNP levels as well as decreased LVEF and systolic BP were significant. Total T(3) levels were reduced, and CRP, cortisol and catecholamines levels were elevated. In the MDys subgroup, anti-TPO Ab positivity and titer were increased. CONCLUSION These results suggest that total T(3) levels may be associated with myocardial contractility, clinical severity, and cortisol levels. Thyroid autoimmunity may influence myocardial contractility in stress CMP.


The Korean Journal of Internal Medicine | 2006

Delayed Puberty due to Pituitary Stalk Dysgenesis and Ectopic Neurohypophysis

Hye Jin Yoo; Kyung Mook Choi; Ohk Hyun Ryu; Sang Il Suh; Nan Hee Kim; Sei Hyun Baik; Dong Seop Choi

Hypopituitarism is not a common cause of delayed puberty. A 22 year old man was referred to our clinic because of the absence of the development of secondary sexual characteristics. The patient had no complaints of physical discomfort. Random serum testosterone and luteinizing hormone level were obtained and found to be low. The combined pituitary function stimulation test revealed a partial hypopituitarism. A pituitary magnetic resonance imaging (MRI) was obtained and showed decreased pituitary stalk enhancement and ectopic neurohypophysis. Therefore, we conclude that the delayed puberty was a result of hypopituitarism due to pituitary stalk dysgenesis and ectopic neurohypophysis. The patient was started on hormone replacement therapy and gradually developed secondary sexual characteristics.


International Journal of Endocrinology | 2016

Cardiac Effects of Thyrotropin Oversuppression with Levothyroxine in Young Women with Differentiated Thyroid Cancer

Kyung-Soon Hong; Jung-Woo Son; Ohk Hyun Ryu; Moon-Gi Choi; Ji Yeon Hong; Seong Jin Lee

Background. We investigated the cardiac effects of TSH (thyroid-stimulating hormone) oversuppression in women with thyroidectomized differentiated thyroid cancer (DTC) during levothyroxine suppression therapy. Methods. Fourteen young female patients with DTC were enrolled. The duration of TSH-suppressive therapy was 5 to 9 years. They satisfied the following criteria: (1) a serum level of TSH < 0.1 mU/L in the intermediate-risk or TSH < 0.3 mU/L in the low-recurrence-risk group and (2) having been receiving a fixed dose of LT4 before the study. Controls matched for age, sex, and body mass index (BMI) were compared in terms of the levels of serum free T4, free T3, TSH, plasma N-terminal pro-brain natriuretic peptide (NT-pro-BNP), and cardiac functions and structures. Results. DTC patients and control subjects were well matched in heart rate and blood pressure. There were marked differences in serum TSH (P = 0.001) and free T4 (P = 0.002). However, there were no differences between the groups in serum free T3 and plasma NT-pro-BNP. Furthermore, there were nonsignificant differences in cardiac functions and structures between the groups. Conclusions. This study shows that TSH suppression therapy in women with DTC may be safe with respect to cardiac functions and structures despite intermittent oversuppression of TSH during long-term suppressive therapy. Trial Registration. This trial is registered with clinicaltrials.gov identifier NCT02645786.


Biochemical and Biophysical Research Communications | 2005

Effect of PPAR-α and -γ agonist on the expression of visfatin, adiponectin, and TNF-α in visceral fat of OLETF rats☆

K.C. Choi; Ohk Hyun Ryu; Kwangyeol Lee; Hyung-Bae Kim; J.A. Seo; Suhyun Kim; N.H. Kim; D. S. Choi; S. H. Baik; Kyung Mook Choi


Diabetes Research and Clinical Practice | 2006

Effects of green tea consumption on inflammation, insulin resistance and pulse wave velocity in type 2 diabetes patients

Ohk Hyun Ryu; Juneyoung Lee; Kwangyeol Lee; Honggon Kim; J.A. Seo; Sin Gon Kim; N.H. Kim; S. H. Baik; Dong Seop Choi; Kyung Mook Choi


Diabetes Research and Clinical Practice | 2007

Serum adiponectin, interleukin-10 levels and inflammatory markers in the metabolic syndrome

Kyung Mook Choi; Ohk Hyun Ryu; Kwangyeol Lee; Honggon Kim; J.A. Seo; Sin Gon Kim; N.H. Kim; Dong Seop Choi; S. H. Baik

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Hee Young Kim

Pusan National University

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Honggon Kim

Korea Institute of Science and Technology

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