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ABSTRACT: Here we examined whether the Matsuda-DeFronzo insulin sensitivity index (ISI-M) is more efficient than the homeostasis model assessment of insulin resistance (HOMA-IR) for assessing risk of hypertension. Cross-sectional and longitudinal analyses were conducted using normotensive subjects who were selected among 1399 subjects in the Tanno-Sobetsu cohort. In the cross-sectional analysis (n=740), blood pressure (BP) level was correlated with HOMA-IR and with ISI-M, but correlation coefficients indicate a tighter correlation with ISI-M. Multiple linear regression analysis adjusted by age, sex, body mass index (BMI) and serum triglyceride level (TG) showed contribution of ISI-M and fasting plasma glucose, but not of HOMA-IR. In the longitudinal analysis (n=607), 241 subjects (39.7%) developed hypertension during a 10-year follow-up period, and multiple logistic regression indicated that age, TG, systolic BP and ISI-M, but not HOMA-IR, were associated with development of hypertension. In subjects <60 years old, odds ratio of new-onset hypertension was higher in the low ISI-M group (ISI-M, less than the median) than in the high ISI-M group for any tertile of BMI. In conclusion, ISI-M is a better predictor of hypertension than is HOMA-IR. Non-hepatic IR may be a determinant, which is independent of TG, BP level and BMI, of the development of hypertension.
Journal of human hypertension 03/2011; 26(5):325-33. · 2.80 Impact Factor
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H Ohnishi,
S Saitoh,
S Takagi,
J Ohata,
H Takeuchi,
T Isobe,
N Katoh,
Y Chiba,
T Fujiwara, H Akasaka,
K Shimamoto
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ABSTRACT: Although it is well known that obesity is closely related to insulin resistance, the incidence of the development of insulin resistance in people with obesity is not known. In this study, we investigated the incidence of insulin resistance in citizens of two rural communities in Japan.
The subjects were 102 men and 126 women over the age of 30 years selected from 1035 citizens who had undergone medical examinations in the towns of Tanno and Sobetsu, Hokkaido, in 1991 and 1998. Those who were on medication for hypertension, diabetes, hyperlipidaemia, coronary heart disease and cerebral vessel disease were excluded. The simple index to determine insulin resistance [i.e. homeostasis model assessment (HOMA-R) > or = 1.73] was used, and subjects who were determined to be positive for insulin resistance according to this index in 1991 were also excluded in order to determine the incidence of insulin resistance in subjects who had no abnormalities other than obesity. The systolic blood pressure (SBP), diastolic blood pressure, body mass index (BMI), triglyceride level, high-density lipoprotein level, blood sugar level, serum insulin value and HOMA-R were measured in all subjects in 1991 and in 1998. Moreover, the subjects were divided into two groups according to BMI, a normal group consisting of subjects with BMI < 25 and an obesity group consisting of subjects with BMI > or = 25. We also compared the incidences of insulin resistance in normal and obesity groups of subjects who were newly determined to be positive for insulin resistance on the basis of data obtained from medical examinations conducted in 1998.
The incidence of insulin resistance was significantly higher in the obesity group than in the normal group (25.0 vs. 4.5%). The results of logistic regression analysis showed that obesity was closely related to insulin resistance and that the relative risk of development of insulin resistance adjusted for age, sex, SBP, FPG and HDL was 3.193 (95% CI 1.085-9.401).
The incidence of insulin resistance was significantly higher in the obesity group than in the normal group in this study, suggesting that improvement in obesity is important for prevention of the occurrence of type 2 diabetes or atherosclerotic disease based on insulin resistance.
Diabetes Obesity and Metabolism 01/2005; 7(1):83-7. · 3.38 Impact Factor
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ABSTRACT: We examined correlations between the frequency of insulin resistance and the accumulation of coronary risk factors in residents of rural comities in Japanese, using simple criteria for determination of insulin resistance based on evaluation by the euglycaemic-hyperinsulinaemic glucose clamp (GC) method. The subjects were 376 men and 589 women living in two rural communities in Japan. We measured body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), HDL cholesterol (HDL), and homeostasis model assessment (HOMA-R). Correlations between HOMA-R and those parameters were examined. To assess the existence of insulin resistance in these subjects, we used a practical index based on the GC method. The subjects with value of HOMA-R >or= 1.73 have insulin resistance. In addition, the HOMA-R was divided into five quantiles based on the frequency distribution (0.60 or below, from 0.61 to 0.82, from 0.83 to 1.18, from 1.19 to 1.69, and 1.70 or higher), to examine the concentration of risk factors in each group. In total, 74 (19.6%) of the men and 119 (20.3%) of the women had insulin resistance (HOMA-R >or= 1.73). It was found that the higher the HOMA-R, the higher was the number of coronary risk factors, such as hypertension, obesity, hypertriglyceridaemia and hypo HDL cholesterolaemia. The number of coronary risk factors was particular high in subjects with HOMA-R >or= 1.70. HOMA-R in the case of no glucose loading is a useful and practical index for evaluation of insulin resistance and coronary risk factors in the epidemiological study.
Diabetes Obesity and Metabolism 11/2002; 4(6):388-93. · 3.38 Impact Factor
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Y. Kawamata,
O. Naito,
K. Kiyono,
K. Itami,
T. Totsuka, H. Akasaka,
M. Sueoka,
T. Sato,
T. Oshima,
S. Sakata,
M. Sato,
H. Takenaga,
T. Suzuki,
N. Oyama,
M. Takechi,
T. Ozeki,
Y. Kamada,
K. Kurihara
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ABSTRACT: The design activity of JT-60SA (JT-60 Super Advanced) addresses the remodeling of JT-60 to a superconducting tokamak device under the JA-EU collaborative ITER–BA project. For the JT-60SA control system, the existing system should be reused as much as possible from the viewpoint of cost-effectiveness. Initial considerations of the configuration of the advanced supervisory control system (SVCS) including the following systems are: (1) an ultimate flexibility real-time control system, (2) a precision timing system able to diagnose a plasma event having a time range of ∼1 μs, and (3) a safety shutdown control system. In this report, we present the design study of the JT-60SA SVCS with the focus on the above systems.
Fusion Engineering and Design.
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ABSTRACT: The JT-60U control system, composed of a UNIX-based workstation and a VME-bus system, has been successfully performing advanced plasma control for the JT-60U plasma discharges. Various hardware modifications and advanced plasma control algorithms have been continuously integrated into the JT-60U control system since its upgrade in 1991. The ZENKEI, the supervisory control system, has been entirely converted from its original 16-bit minicomputers and CAMAC system to the combination of a workstation and VME-bus system linked through an Ethernet network. The plasma equilibrium control system utilizes a full VME-bus system composed of three DEC alpha CPU modules that are currently running at control cycle times of 250 μs. The parameters for plasma equilibrium control are calculated by a newly developed real-time plasma shape calculation and reconstruction system. These parameters are fed to the plasma equilibrium control system synchronized by 250-μs clock pulses. To progress toward the advanced plasma control concept, which includes adoption of a global plasma parameter control algorithm and suppression of MHD instabilities, improvements were extensively consolidated into the plasma control system (PCS). Currently, additional modifications of the JT-60U control system have extended the pulse duration of the discharge without a major change in JT-60 equipment.
Fusion Engineering and Design.
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ABSTRACT: The sustainment of radiative divertor plasma in JT-60U is performed by the feedback control of the gas puffing rate into the divertor region with an actuator of the divertor radiation power. The feedback control system switches the piezoelectric gas valve every 10 ms, so that the proper amount of gas flux is fed for divertor radiation power to follow the reference waveform. The divertor radiation of 6 MW, which is about 40% of the heating power, is sustained for about 3 s by the hydrogen gas puffing with feedback control. The present logic of the feedback system, however, is not sufficient to fully control the divertor radiation which is modified by the change in heatings and plasma parameters. In order to prevent the loss of control, multi actuators for the feedback control, for example, the involvement of the heating power, and the selection of observed bolometer channels may be required.
Fusion Engineering and Design.
