Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
Articles by S. Okada
Total Records ( 4 ) for S. Okada
  Y Minamiyama , S Takemura , S Kodai , H Shinkawa , T Tsukioka , H Ichikawa , Y Naito , T Yoshikawa and S. Okada

Accumulating evidence suggests that alcohol, hepatitis C virus infection, steatosis with obesity, and insulin resistance are accompanied by iron overload states. Phlebotomy and oral iron chelators are effective treatments for these conditions and for hemochromatosis. However, the mechanisms by which iron depletion improves clinical factors remain unclear. We examined the effect of iron depletion in a model of type 2 diabetes, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Age-matched Long-Evans Tokushima Otsuka (LETO) rats were used as controls for all experiments. Iron restriction was performed by eliminating iron in the diet from 15 wk of age or by phlebotomy. Phlebotomy was commenced at 29 wk of age by removing 4 and 3 ml of blood from the tail vein every week in OLETF and LETO rats, respectively. Rats were euthanized at 43 wk of age, and detailed analyses were performed. The plasma ferritin concentration was markedly higher in OLETF rats and decreased in iron-deficient (ID) diet and phlebotomy rats. Hemoglobin A1c (Hb A1c) was decreased significantly in OLETF rats fed the ID diet and in the phlebotomy group. Increased levels of triglycerides, glucose, free fatty acids, and total cholesterol were found in ID OLETF rats. Plasma, liver, and pancreas lipid peroxidation and hepatic superoxide production decreased in both groups. Pancreatic fibrosis and insulin levels improved in both groups of OLETF rats. Pancreatic levels of peroxisome proliferator-activated receptor-β/ (PPARβ/) ligands and hypoxia-inducible factor (HIF)-1 were decreased significantly in OLETF rats. These factors were normalized in both rats fed ID and phlebotomy groups of OLETF rats. In conclusion, iron depletion improved diabetic complications by inhibition of oxidative stress and TGFβ signal pathways and the maintenance of pancreatic PPARβ/ and HIF-1 pathways.

  K. Kita , S. Okada , H. Sekino , K. Imou , S. Yokoyama and T. Amano
  Botryococcus braunii, a green colonial microalga, is an unusually rich renewable source of hydrocarbons. In this study, wet microalgae harvest was thermally pretreated to enhance hydrocarbon recovery using a solvent extraction process. Samples containing a mixture of B. braunii and water were kept below 100  °C for 10 min. The observed hydrocarbon recovery was 97.8% at 90 °C. The extraction results suggest that the energy-intensive concentration and drying processes of the harvest could be eliminated. The proposed thermal pretreatment would revolutionize the conventional downstream processes.
  H. Makino , S. Okada , A. Nagumo , T. Sugisawa , Y. Miyamoto , I. Kishimoto , A. Kikuchi-Taura , T. Soma , A. Taguchi and Y. Yoshimasa
  Aims  Circulating progenitor cells such as CD34+ cells play a key role in maintenance of vascular endothelial function and neovascularization, and a decrease in the number of CD34+ cells is associated with cardiovascular disease. However, the contribution of circulating progenitor cells to microvascular disease, such as diabetic nephropathy, is unclear. This study was therefore designed to clarify the association between diabetic nephropathy and circulating CD34+ cells.

Methods  We measured circulating CD34+ cell numbers in 85 Type 2 diabetic patients aged 40-70 years with normo- and microalbuminuria and determined the association with urinary albumin excretion rate (UAER).

Results  The number of circulating CD34+ cells significantly correlated with log UAER (r = -0.289, P = 0.008). Furthermore, in patients with low numbers of CD34+ cells (0.68 > cells/μl, lowest quartile of CD34+ cell number) UAER increased significantly after 12 months compared with baseline [from 34.3 ± 7.0 to 53.6 ± 10.8 mg/g creatinine (gCr), P < 0.05], whereas in patients with a high number of CD34+ cells (1.0 < cells/μl, highest quartile of CD34+ cell number) UAER did not change (from 16.7 ± 4.8 to 20.1 ± 3.0 mg/gCr).

Conclusions  These results suggest that a decreased number of circulating CD34+ cells is involved in the progression of diabetic nephropathy and may be a predictor of the disease.

  T. Ando , S. Okada , Y. Niijima , K. Hashimoto , H. Shimizu , T. Tsuchiya , M. Yamada , K. Ohshima , M. Mori and K. Ono
  Aims  The study aimed to investigate early-stage atherosclerosis in patients with impaired fasting glucose compared with patients with impaired glucose tolerance.

Methods  Body mass index, systolic blood pressure, fasting plasma glucose, lipid variables, ankle-brachial pressure index and brachial-ankle pulse wave velocity were measured in 2842 subjects from Takasaki city located approximately 100 km north of Tokyo in Japan. The subjects were divided into the following five groups based on a 75-g oral glucose tolerance test: (i) normal fasting plasma glucose/normal glucose tolerance group, (ii) impaired fasting glucose group, (iii) impaired glucose tolerance group, (iv) combined glucose intolerance group and (v) diabetic glucose intolerance group.

Results  In comparison with fasting plasma glucose levels (r = 0.269, P < 0.0001), 2-h post-challenge glucose levels were more closely correlated with pulse wave velocity values (r = 0.300, P < 0.0001). The groups with impaired glucose tolerance, combined glucose intolerance and diabetic glucose intolerance had significantly higher pulse wave velocity values compared with the groups with normal glucose tolerance and impaired fasting glucose. Multiple regression analyses showed an independent association of age, systolic blood pressures, total cholesterol, fasting and 2h plasma glucose with pulsewave velocityvalues. Furthermore, pulse wave velocity was not significantly correlated with fasting plasma glucose, but was correlated with increased 2h plasma glucose.

Conclusions  Groups with impaired glucose tolerance and combined glucose intolerance had significantly higher brachio-ankle pulse wave velocity values compared with the group with normal glucose tolerance. Although the group with impaired fasting glucose showed a marginal increase in pulse wave velocity values compared with the group with normal glucose tolerance, the difference was not significant. Thus impaired glucose tolerance, but not impaired fasting glucose, is a risk factor for early-stage atherosclerosis.

Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility