Yoshikazu Umeno

Oita University, Ōita, Ōita, Japan

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Publications (14)45.14 Total impact

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    ABSTRACT: The elevated level of high-sensitivity C-reactive protein (HSCRP) is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of HSCRP correlates with hippocampus volume and insulin resistance in nondementia patients with type 2 diabetes mellitus. Subjects included 45 nondementia patients with type 2 diabetes mellitus, who were divided into 2 groups: high-HSCRP group (age, 65 ± 6 years [mean ± SD]; n = 17) and normal-HSCRP group (65 ± 7 years, n = 28). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging voxel-based specific regional analysis system developed for the study of Alzheimer disease (VSRAD), which yields a z score as the end point for assessment of hippocampal volume. The z score was higher in the high-HSCRP group than in the normal-HSCRP group (P < .0001). The fasting plasma glucose (P < .05) and insulin concentrations (P < .0001) and the homeostasis model assessment (HOMA) index (P < .0001) were higher in the high-HSCRP group than in the normal-HSCRP group. Multiple regression analysis showed that HSCRP levels were independently predicted by z score and HOMA index. Our results indicate that the elevated level of HSCRP in Japanese nondementia patients with type 2 diabetes mellitus is characterized by increased hippocampus volume and insulin resistance, and that the z score and HOMA index are independent predictors of HSCRP.
    Metabolism: clinical and experimental 04/2011; 60(4):460-6. · 3.10 Impact Factor
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    ABSTRACT: Elevated total plasma homocysteine (tHcy) levels are associated with cognitive dysfunction, in which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that elevated tHcy levels are correlated with hippocampus volume and insulin resistance in nondementia patients with type 2 diabetes. The study included 43 nondementia patients with type 2 diabetes, who were divided into two groups: a high tHcy group (age: 65 ± 8 years, mean ± standard deviation, n = 16) and a normal tHcy group (64 ± 9 years, n = 27). Hippocampus volume was quantified with a computer-assisted analysis using a magnetic resonance imaging (MRI) voxel-based specific regional analysis system developed for the study of Alzheimer's disease (VSRAD), which yields a Z-score as the end point for the assessment of hippocampal volume. Results  The Z-score was higher in the high tHcy group compared to the normal tHcy group (P < 0·0001). The fasting plasma glucose (P < 0·01) and insulin (P < 0·0001) concentrations and the homoeostasis model assessment (HOMA) index (P < 0·0001) were higher in the high tHcy group than in the normal tHcy group. Multiple regression analysis showed that the main factors that influenced tHcy levels may be the Z-score and the HOMA index. Our results indicate that the elevated levels of tHcy in Japanese nondementia patients with type 2 diabetes are characterised by hippocampal atrophy and insulin resistance and that the Z-score and HOMA index may be the primary factors that influence tHcy levels.
    European Journal of Clinical Investigation 01/2011; 41(7):751-8. · 3.37 Impact Factor
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    ABSTRACT: The presence of diabetic retinopathy (DR) and increased of visceral fat accumulation (VFA) are associated with high mortality in type 2 diabetes mellitus patients. This preliminary study was therefore designed to test the hypothesis that DR is associated with insulin resistance and VFA in type 2 diabetes mellitus patients without insulin treatment. A total of 102 type 2 diabetes mellitus patients were divided into 2 groups: DR group (age, 60 +/- 6 years [mean +/- SD]; n = 31) and no diabetic retinopathy (NDR) group (59 +/- 5 years, n = 71). The level of blood glucose was assessed by fasting plasma glucose, fasting immunoreactive insulin, homeostasis model assessment index, and hemoglobin A(1c). The fat distribution was evaluated by measuring the VFA by abdominal computed tomography at the umbilical level. The body mass index and waist circumference were higher in the DR group than in the NDR group (P < .001 and P < .0005, respectively). Plasma levels of triglyceride were higher, whereas high-density lipoprotein cholesterol was lower, in the DR group than in the NDR group (P < .005 and P < .0001, respectively). Fasting plasma glucose (P < .0005), insulin concentrations (P < .0001), homeostasis model assessment index (P < .0001), and VFA (P < .0001) levels were higher in the DR group than in the NDR group. Multivariate logistic analysis revealed that DR was independently predicted by high VFA and insulin resistance. The results of this preliminary study indicate that the presence of DR was associated with high VFA and insulin resistance in Japanese patients with type 2 diabetes mellitus.
    Metabolism: clinical and experimental 12/2009; 59(3):314-9. · 3.10 Impact Factor
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    ABSTRACT: The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. High-sensitivity C-reactive protein (HSCRP), which is associated with diabetes, has been flagged as a novel predictor for cerebrovascular events. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with HSCRP and insulin resistance in type 2 diabetic patients not receiving insulin treatment. Based on brain magnetic resonance imaging (MRI) findings, 102 type 2 diabetic patients were divided into two groups; a WML-positive group (59+/-6 years, mean+/-SD, n=40) and a WML-negative group (58+/-6 years, n=62). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin (F-IRI), homeostasis model assessment (HOMA) index, and Hemoglobin A1c (HbA1c). The body mass index was higher in the WML-positive group than in the WML-negative group (p<0.05). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol (HDL-C) was lower in the WML-positive group than in the WML-negative group (p<0.01 and p<0.005, respectively). Fasting plasma glucose (p<0.005), insulin concentrations (p<0.0001), HOMA index (p<0.0001), and HSCRP (<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the high HSCRP and insulin resistance (p<0.005, p<0.0005, respectively). The results of this preliminary study indicate that the presence of WML was associated with the high HSCRP and insulin resistance in these Japanese patients with type 2 diabetes mellitus; larger cohort studies are warranted to confirm these findings.
    Diabetes research and clinical practice 11/2009; 87(2):233-9. · 2.74 Impact Factor
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    ABSTRACT: Obesity is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of visceral fat accumulation (VFA) correlates with hippocampus volume and insulin resistance in non-dementia patients with type 2 diabetes. Subjects included 48 non-dementia patients with type 2 diabetes, who were divided into two groups, high VFA group (mean+/-standard deviation: age=65+/-6 years, n=30) and normal VFA group (65+/-5 years, n=18). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging (MRI) voxel-based specific regional analysis system developed for the study of Alzheimer's disease (VSRAD), which yields a Z-score as the end point for assessment of hippocampal volume. The Z-score was higher in the high VFA group than in the normal VFA group (p<0.0001). The fasting plasma glucose (p<0.05) and insulin concentrations (p<0.0001) and the homeostasis model assessment (HOMA) index (p<0.0001) were higher in the high VFA group than in the normal VFA group. Multiple regression analysis showed that VFA levels were independently predicted by Z-score and HOMA index. Our results indicate that the elevated level of VFA in Japanese non-dementia patients with type 2 diabetes is characterized by increased hippocampus volume and insulin resistance, and that the Z-score and HOMA index are independent predictors of VFA.
    NeuroImage 09/2009; 49(1):57-62. · 6.25 Impact Factor
  • Tsuyoshi Shimomura, Tadayuki Kaku, Yoshikazu Umeno
    Journal of Clinical Neuroscience 04/2009; 16(3):426, 483. · 1.25 Impact Factor
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    ABSTRACT: The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. The elevated visceral fat accumulation (VFA) has been reported to be closely related to the development of atherosclerosis. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with VFA and insulin resistance in type 2 diabetic patients not receiving insulin treatment. Based on brain magnetic resonance imaging (MRI), 95 type 2 diabetic patients were divided into two groups: WML-positive group (aged 59 +/- 7 years, mean +/- SD n = 37) and WML-negative group (aged 58 +/- 5, years, n = 58). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin, homeostasis model assessment (HOMA) index, and haemoglobin A1c. The fat distribution was evaluated by measuring the visceral fat accumulation by abdominal computerized tomography at the umbilical level. The body mass index was higher in the WML-positive group than in the WML-negative group (P < 0.005). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol was lower in the WML-positive group than in the WML-negative group (P < 0.05 and P < 0.01, respectively). FPG (P < 0.01), insulin concentrations (P < 0.0001), HOMA index (P < 0.0001) and VFA (<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the high VFA and insulin resistance (P < 0.001, P < 0.0001, respectively). The results of this preliminary study indicate that the presence of WML was associated with the high VFA and insulin resistance in Japanese patients with type 2 diabetes mellitus. Further larger cohort studies are warranted to confirm these findings.
    European Journal of Clinical Investigation 04/2009; 39(5):368-74. · 3.37 Impact Factor
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    ABSTRACT: The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. Microalbuminuria, which is associated with diabetes, has been flagged as a novel predictor for cerebrovascular events. This preliminary study was therefore designed to test the hypothesis that the presence of WML correlates with microalbuminuria and insulin resistance in patients with type 2 diabetic mellitus (DM) not receiving insulin treatment. Based on brain magnetic resonance imaging (MRI) findings, 90 type 2 diabetic patients were divided into two groups: a WML-positive group (57+/-8 years, mean+/-SD, n=34) and a WML-negative group (57+/-6 years, n=56). The level of blood glucose was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin (F-IRI), homeostasis model assessment (HOMA) index, and hemoglobin A(1c) (HbA1c). The body mass index was higher in the WML-positive group than in the WML-negative group (p<0.01). Plasma levels of triglycerides were higher while high-density lipoprotein cholesterol (HDL-C) was lower in the WML-positive group than in the WML-negative group (p<0.05 and p<0.0001, respectively). Fasting plasma glucose (p<0.005), insulin concentrations (p<0.0001), HOMA index (p<0.0001), and urinary albumin excretion (p<0.0001) levels were higher in the WML-positive group than in the WML-negative group. Multivariate logistic analysis revealed that WML was independently predicted by the microalbuminuria and insulin resistance (p<0.005, p<0.0005, respectively). The results of this preliminary study indicate that the presence of WML was associated with the microalbuminuria and insulin resistance in these Japanese patients with type 2 DM; larger cohort studies are warranted to confirm these findings.
    Current Medical Research and Opinion 06/2008; 24(6):1561-7. · 2.37 Impact Factor
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    ABSTRACT: The presence of white matter lesions (WML) is an important prognostic factor for the development of stroke. Plasma total homocysteine (tHcy), which increases with diabetes, has been flagged as a novel predictor for cerebrovascular events. We tested the hypothesis that the presence of WML correlates with tHcy and insulin resistance in type 2 diabetic patients not receiving insulin treatment. Based on brain magnetic resonance imaging findings, 81 type 2 diabetic patients were divided into two groups, with-WML group (57 +/- 8 years, mean +/- standard deviation, n = 31) and without-WML group (57 +/- 6 years, n = 50). The blood glucose level was assessed by fasting plasma glucose (FPG), fasting immunoreactive insulin, Homeostasis Model Assessment (HOMA) Index and hemoglobin A1c. The body mass index was higher in the with-WML group than in the without-WML group (P < 0.05). Plasma levels of triglyceride were higher whilst high-density lipoprotein cholesterol was lower in the with-WML group than in the without-WML group (P < 0.05 and P < 0.0001 respectively). FPG (P < 0.005), insulin concentrations (P < 0.0001), HOMA Index (P < 0.0001) and tHcy (<0.0001) levels were higher in the with-WML group than in the without-WML group. Multivariate logistic analysis revealed that WML was independently predicted by the high tHcy and insulin resistance. Our findings indicate that the presence of WML was associated with the high tHcy and insulin resistance in these Japanese patients with type 2 diabetes mellitus.
    European Journal of Neurology 03/2008; 15(3):289-94. · 4.16 Impact Factor
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    ABSTRACT: We tested the hypothesis that increased abdominal visceral fat accumulation (VFA) is associated with insulin resistance and aortic stiffness in patients with type 2 diabetes mellitus not receiving insulin treatment. The study consisted of 22 Japanese patients with type 2 diabetes mellitus and high VFA (> or =100 cm(2); age, 61 +/- 7 years; high VFA group) and a control group of 18 age-matched patients with normal VFA (<100 cm(2); age, 60 +/- 8 years; normal VFA group). Brachial-ankle pulse wave velocity (BaPWV) was measured by automatic oscillometric method. The BaPWV was used as an index of atherosclerosis. The body mass index values (P < .05), waist circumferences (P < .0005), and waist-to-hip ratios (P < .05) were larger in the high VFA group than in the normal VFA group. The BaPWV was higher in the high VFA group than in the normal VFA group (P < .0001). Fasting plasma glucose (P < .05), insulin concentrations (P < .0001), and the homeostasis model assessment (HOMA) index (P < .001) were higher in the high VFA group than in the normal VFA group. Multiple regression analysis showed that the VFA level was independently predicted by BaPWV and the HOMA index. Our results indicate that the elevation of VFA in Japanese patients with type 2 diabetes mellitus is characterized by increased aortic stiffness and insulin resistance and that BaPWV and the HOMA index are independent predictors of VFA.
    Metabolism 02/2008; 57(2):280-4. · 3.10 Impact Factor
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    ABSTRACT: Elevated total plasma homocysteine (tHcy) level and aortic stiffness are associated with high mortality in type 2 diabetic patients. We tested the hypothesis that tHcy correlates with aortic stiffness and insulin resistance in type 2 diabetic patients. The study consisted of 40 Japanese patients with type 2 diabetes mellitus and high tHcy levels (mean age +/- SD, 57 +/- 7 years) and a control group of 45 age-matched patients with normal tHcy levels (mean age +/- SD, 57 +/- 6 years). Brachial-ankle pulse wave velocity (BaPWV) was measured by an automatic oscillometric method. Brachial-ankle pulse wave velocity was used as an index of atherosclerosis. Body mass index values (P < .05), waist circumferences (P < .05), and the waist-to-hip ratios (P < .05) were larger in the high-tHcy group than in the normal-tHcy group. The BaPWV was higher in the high-tHcy group than in the normal-tHcy group (P < .0001). Fasting plasma glucose (P < .005) and insulin concentrations (P < .0001), and the homeostasis model assessment (HOMA) index (P < .0001) were higher in the high-tHcy group than in the normal-tHcy group. Multiple regression analysis showed that tHcy levels were independently predicted by BaPWV and the HOMA index. In conclusion, our results indicate that the elevated level of tHcy in Japanese patients with type 2 diabetes mellitus is characterized by increased aortic stiffness and insulin resistance, and that the BaPWV and the HOMA index are independent predictors of tHcy.
    Metabolism 11/2007; 56(10):1390-5. · 3.10 Impact Factor
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    ABSTRACT: Insulin resistance significantly correlated with a non-dipper type of essential hypertension. Thiazolidinediones (TZD), oral hypoglycaemic agents that act as insulin sensitizers, have been demonstrated in multiple in vivo and in vitro studies to possess antihypertensive properties. This study examined the efficacy of TZD therapy with pioglitazone at transforming the circadian rhythms of blood pressure from a non-dipper to a dipper type. We examined 31 patients with type 2 diabetes mellitus during both a baseline period and a period of treatment with pioglitazone. Patients received 15 mg day(-1) pioglitazone for four weeks and 30 mg day(-1) for 12 weeks. Twenty-four hour ambulatory blood pressure monitoring (ABPM) and laboratory data (blood tests for cardiovascular risk factors) were obtained at the beginning and end of the study. In non-dippers (n = 16), but not dippers (n = 15), we observed a significant interaction between pioglitazone therapy and nocturnal falls in systolic and diastolic blood pressure. This examination indicated that the magnitude of the nocturnal blood pressure fall was affected by pioglitazone therapy. In non-dippers, but not dippers, a significant correlation was observed between the percent decrease in nocturnal BP and the homeostasis model assessment (HOMA) index (r = 0.774, P = 0.0007). The present study demonstrated that pioglitazone can restore the nocturnal BP declines in parallel to reductions in the HOMA index, suggesting that insulin resistance may play an important role in the genesis of circadian BP rhythms. TZD-based treatment may thus have the additional therapeutic advantage of reducing the risk of cardiovascular complications by transforming the circadian rhythm of BP.
    European Journal of Clinical Investigation 10/2007; 37(9):709-14. · 3.37 Impact Factor
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    ABSTRACT: The elevated level of high-sensitivity C-reactive protein (HSCRP) and aortic stiffness are associated with high mortality in type 2 diabetic patients. We tested the hypothesis that the HSCRP correlates with aortic stiffness and insulin resistance in type 2 diabetic patients. The study consisted of 46 Japanese patients with type 2 diabetes and high HSCRP group (0.3-1.0 mg/dl, age: 57+/-5 years, mean+/-s.d.) and a control group of 55 age-matched patients with low HSCRP group (<0.3 mg/dl, 57+/-6 years). Brachial-ankle pulse wave velocity (BaPWV) was measured by automatic oscillometric method and was used as an index of atherosclerosis. The body mass index (BMI) values (P<0.05) and waist circumferences (P<0.0005) and the waist-to-hip ratios (P<0.05) were higher in the high HSCRP group than in the low HSCRP group. The BaPWV was higher in the high HSCRP group than in the low HSCRP group (P<0.0001). Fasting plasma glucose (FPG; P<0.005) and insulin concentrations (P<0.0001), and the homeostasis model assessment (HOMA) index (P<0.0001), were higher in the high HSCRP group than in the low HSCRP group. Multiple regression analysis showed that HSCRP levels were independently predicted by BaPWV and HOMA index. Our results indicate that the elevated level of HSCRP in Japanese patients with type 2 diabetes is characterized by increased aortic stiffness and insulin resistance, and that the BaPWV and HOMA index are independent predictors of HSCRP.
    European Journal of Endocrinology 10/2007; 157(3):311-7. · 3.14 Impact Factor
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    ABSTRACT: Microalbuminuria and aortic stiffness are associated with high mortality in type 2 diabetic patients. We tested the hypothesis that the presence of microalbuminuria correlates with aortic stiffness and insulin resistance in type 2 diabetic patients. The study consisted of 36 Japanese patients with type 2 diabetes and microalbuminuria (age: 56+/-9 years, mean+/-S.D.) and a control group of 44 age-matched patients with normoalbuminuria (56+/-7 years). Brachial-ankle pulse wave velocity (BaPWV) was measured by automatic oscillometric method. BaPWV was used as an index of atherosclerosis. The BaPWV was higher in the microalbuminuria group than in the normoalbuminuria group (p<0.005). Fasting plasma glucose (p<0.05) and insulin concentrations (p<0.005), and the homeostasis model assessment (HOMA) index (p<0.0005), were higher in the microalbuminuria group than in the normoalbuminuria group. Multiple regression analysis showed that urinary albumin excretion was independently predicted by BaPWV and HOMA index. Our results indicate that the presence of microalbuminuria in Japanese patients with type 2 diabetes is characterized by increased aortic stiffness and insulin resistance, and that the BaPWV, HOMA index are independent predictors of urine albumin excretion.
    Diabetes Research and Clinical Practice 09/2007; 77(3):414-9. · 2.74 Impact Factor