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15 results on '"Ahn, Yu-Bai"'

9. Glucose-dependent Insulin Secretion from Genetically Engineered K-cells Using EBV-based Episomal Vector

Author

Kim, Ju-Hee, primary, Moon, Sung-Dae, additional, Ko, Seung-Hyun, additional, Ahn, Yu-Bai, additional, Song, Ki-Ho, additional, Lim, Hyang-Sook, additional, Lee, Sook-Kyung, additional, Yoo, Soon-Jip, additional, Son, Hyun-Shik, additional, Yoon, Kun-Ho, additional, Cha, Bong-Yun, additional, Son, Ho-Young, additional, Yoon Kim, Sung-Joo, additional, and Han, Je-Ho, additional

Published
2007
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11. Cardiovascular Autonomic Neuropathy in Patients with Type 2 Diabetes Mellitus

Author

Ko, Seung-Hyun, primary, Kwon, Hyuk-Sang, additional, Lee, Jung-Min, additional, Kim, Sung-Rae, additional, Cho, Jae-Hyung, additional, Yoo, Ki-Dong, additional, Park, Yong-Moon, additional, Lee, Won-Chul, additional, Song, Ki-Ho, additional, Yoon, Kun-Ho, additional, Cha, Bong-Yun, additional, Son, Ho-Young, additional, and Ahn, Yu-Bai, additional

Published
2006
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14. Critical reduction in beta-cell mass results in two distinct outcomes over time. Adaptation with impaired glucose tolerance or decompensated diabetes.

Author

Laybutt, D Ross, Glandt, Mariela, Xu, Gang, Ahn, Yu Bai, Trivedi, Nitin, Bonner-Weir, Susan, and Weir, Gordon C

Abstract

We have proposed that hyperglycemia-induced dedifferentiation of beta-cells is a critical factor for the loss of insulin secretory function in diabetes. Here we examined the effects of the duration of hyperglycemia on gene expression in islets of partially pancreatectomized (Px) rats. Islets were isolated, and mRNA was extracted from rats 4 and 14 weeks after Px or sham Px surgery. Px rats developed different degrees of hyperglycemia; low hyperglycemia was assigned to Px rats with fed blood glucose levels less than 150 mg/dl, and high hyperglycemia was assigned above 150 mg/dl. beta-Cell hypertrophy was present at both 4 and 14 weeks. At the same time points, high hyperglycemia rats showed a global alteration in gene expression with decreased mRNA for insulin, IAPP, islet-associated transcription factors (pancreatic and duodenal homeobox-1, BETA2/NeuroD, Nkx6.1, and hepatocyte nuclear factor 1 alpha), beta-cell metabolic enzymes (glucose transporter 2, glucokinase, mitochondrial glycerol phosphate dehydrogenase, and pyruvate carboxylase), and ion channels/pumps (Kir6.2, VDCC beta, and sarcoplasmic reticulum Ca(2+)-ATPase 3). Conversely, genes normally suppressed in beta-cells, such as lactate dehydrogenase-A, hexokinase I, glucose-6-phosphatase, stress genes (heme oxygenase-1, A20, and Fas), and the transcription factor c-Myc, were markedly increased. In contrast, gene expression in low hyperglycemia rats was only minimally changed at 4 weeks but significantly changed at 14 weeks, indicating that even low levels of hyperglycemia induce beta-cell dedifferentiation over time. In addition, whereas 2 weeks of correction of hyperglycemia completely reverses the changes in gene expression of Px rats at 4 weeks, the changes at 14 weeks were only partially reversed, indicating that the phenotype becomes resistant to reversal in the long term. In conclusion, chronic hyperglycemia induces a progressive loss of beta-cell phenotype with decreased expression of beta-cell-associated genes and increased expression of normally suppressed genes, these changes being present with even minimal levels of hyperglycemia. Thus, both the severity and duration of hyperglycemia appear to contribute to the deterioration of the beta-cell phenotype found in diabetes.

Published
2003
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15. Progression of Cardiovascular Autonomic Neuropathy and Cardiovascular Events in Type 2 Diabetic Patients.

Author

Park, Yong-Moon, Ahn, Yu-Bai, Song, Ki-Ho, Yoo, Ki-Dong, Yoon, Kun-Ho, Cha, Bong-Yun, Son, Ho-Young, and Ko, Seung-Hyun

Subjects
*DIABETIC neuropathies, *PEOPLE with diabetes, *DIABETES complications, *TYPE 2 diabetes, *CORONARY disease, *CARDIOVASCULAR diseases
Abstract

Diabetic autonomic neuropathy has a significantly negative impact on survival and quality of life in type 2 diabetic patients. Especially, cardiovascular autonomic neuropathy (CAN) is clinically important, because of its association with cardiovascular death. We investigated whether the progression of CAN is related to the cardiovascular events in type 2 diabetic patients. Total 683 type 2 diabetic patients, 244 males and 439 females, visited Diabetes Clinic. Autonomic function test at baseline was conducted from January 2000 to December 2000, and was followed from January 2006 to December 2006. Standard tests for CAN were composed of heart rate variability (E/I ratio, response to the Valsalva maneuver and standing). CAN score was determined by the results of each test as following: 0=normal, 1 =abnormal (total score 3). Progress was defined when the total score at follow was higher than the baseline score. Total 425 patients were evaluated after six years. Mean age and duration of diabetes were 58.1 ± 10.3, and 8.3 ± 7.0 years, respectively. Among the total number of patients, 106 patients (24.9%) were the group in progress. 53 patients (12.5%) developed cerebral infarction (CVA), and 46 patients (10.8%) experienced ischemic heart attack (CAD; angina, myocardial infarction) during the observation period. There were no differences in body mass index, postprandial hyperglycemia, and HbA1c level between two groups. Compared to group in non-progress, both CAD and CVA were developed more frequently in 'progress' group (21.7 vs. 14.7%, P<0.05). The incidence of vascular events were higher in patients with older age (P=0.008), longer diabetic duration (P=0.003), hypertension (P<0.001), and diabetic retinopathy (p=0.0013). Patients with CVA or CHD had lower HDL cholesterol level (39.1 ± 10.7 vs. 42.1 ± 10.8 mg/dl, p < 0.05), and higher fasting insulin (14.0 ± 14.2 vs. 9.6 ± 10.1 µIU/ml, p < 0.05) than patients without CVA or CHD. Logistic regression analysis revealed the progress of CAN score to be deeply related to the development of vascular event (OR 2.487, CI 1.134-5.458, P=0.023). These results suggest that cardiovascular autonomic function could predict the development of CVA or CAD, therefore, it could be a good screening method for the cardiovascular events in type 2 diabetic patients. [ABSTRACT FROM AUTHOR]

Published
2007

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