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Dive into the research topics where Kazuko Okada is active.

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Featured researches published by Kazuko Okada.


Journal of Gastroenterology | 2002

Severe catabolic state after prolonged fasting in cirrhotic patients: effect of oral branched-chain amino-acid-enriched nutrient mixture

Yutaka Nakaya; Nagakatsu Harada; Sae Kakui; Kazuko Okada; Akira Takahashi; Junnya Inoi; Susumu Ito

Background:Background: Cirrhotic patients frequently undergo various medical procedures, such as diagnostic gastrointestinal endoscopy, without taking breakfast. The aim of the present study was to clarify the effect of longer fasting (>12 h) on energy metabolism, and to test whether supplementation of an oral branched-chain amino-acid-enriched nutrient mixture (BCAA mixture), which contains various nutrients in addition to BCAA, could improve the catabolic state. Methods: Metabolic measurement was performed in 30 cirrhotic patients and 13 normal subjects, using indirect calorimetry. Results: Compared with that in the normal subjects, the respiratory quotient (RQ) was significantly lower after an overnight fast in the cirrhotic patients, indicating accelerated fat oxidation and a catabolic state. In addition, RQ in cirrhotic patients (n= 7) decreased rapidly with longer fasting, whereas that in the normal subjects (n= 5) showed relatively stable values. These results indicate that special care should be taken with medical procedures that are carried out in patients who have fasted. The effect of oral glucose, a carbohydrate-rich snack (rice ball), and the BCAA mixture (each, 210 kcal) on RQ was studied in 6 normal subjects and 6 patients with liver cirrhosis after an overnight fast. Supplementation of the carbohydrate-rich snack and the BCAA mixture (210 kcal each) elevated RQ and blood glucose levels to a similar degree in the cirrhotic patients. Oral administration of glucose (210 kcal) led to significantly greater elevation of blood glucose levels than the other snacks, which may be unfavorable for cirrhotic patients, who frequently have glucose intolerance. In the 30 cirrhotic patients, supplementation with the BCAA mixture in the late evening significantly improved RQ in the early morning. Conclusions: Carbohydrate-rich meals are used as a late evening snack in cirrhotic patients, but our study indicates that supplementation with a BCAA mixture can also be used to reduce fat oxidation in the early morning, with results similar to those with carbohydrate-rich snacks.


British Journal of Nutrition | 2002

Effect of eicosapentaenoic acid ethyl ester v. oleic acid-rich safflower oil on insulin resistance in type 2 diabetic model rats with hypertriacylglycerolaemia

Asako Minami; Noriko Ishimura; Sadaichi Sakamoto; Eiko Takishita; Kazuaki Mawatari; Kazuko Okada; Yutaka Nakaya

The purpose of the present study was to test whether hyperlipidaemia and insulin resistance in type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats can be improved by dietary supplementation with purified eicosapentaenoic acid (EPA) or oleic acid (OA). Male OLETF rats were fed powdered chow (510 g fat/kg) alone (n 8) or chow supplemented with 10 g EPA- (n 8) or OA- (n 8) rich oil/kg per d from 5 weeks until 30 weeks of age. An oral glucose tolerance test and hyperinsulinaemic euglycaemic clamp was performed at 25 and 30 weeks of age. EPA supplementation resulted in significantly (P<0.05) reduced plasma lipids, hepatic triacylglycerols, and abdominal fat deposits, and more efficient in vivo glucose disposal compared with OA supplementation and no supplementation. OA supplementation was associated with significantly increased insulin response to oral glucose compared with EPA supplementation and no supplementation. Inverse correlation was noted between glucose uptake and plasma triacylglycerol levels (r -086, P<0.001) and abdominal fat volume (r -0.80, P<0.001). The result of oral glucose tolerance test study showed that the rats fed EPA tended to improve glucose intolerance, although this was not statistically significant. Levels of plasma insulin at 60 min after glucose was significantly increased in rats fed OA compared with the other two groups. The results indicate that long-term feeding of EPA might be effective in preventing insulin resistance in diabetes-prone rats, at least in part, due to improving hypertriacylglycerolaemia.


European Journal of Pharmacology | 1998

A lipoprotein lipase activator, NO-1886, improves endothelium-dependent relaxation of rat aorta associated with aging

Tsutomu Hara; Masataka Kusunoki; Kazuhiko Tsutsumi; Kazuko Okada; Sadaichi Sakamoto; Masaharu Ohnaka; Takao Nakamura; Tetsuro Miyata; Kaori Nakayama; Atsushi Fukatsu; Katsumi Kato; Shinichi Kakumu; Yutaka Nakaya

Endothelial function is closely related to development of atherosclerosis and is impaired with aging. The novel compound NO-1886, 4-diethoxyphosphorylmethyl-N-(4-bromo-2-cyanophenyl)benzamid e, is a lipoprotein lipase activator and its long term administration protects against the development of experimental atherosclerosis in animals. The aim of this study was to ascertain whether NO-1886 ameliorates the impaired endothelium-dependent relaxation of rat aorta associated with aging. NO-1886 (50 mg/kg p.o.) was administered to 7-month old rats for 3 months. Plasma lipid, glucose and insulin levels in old control rats (10 months of age) were significantly higher than those of young rats (2 months of age). NO- 1886 decreased plasma triglyceride levels (old rats, 233+/-10 mg/dl; old rats + NO-1886, 172+/-16 mg/dl, P < 0.01) and increased plasma high density lipoprotein (HDL) cholesterol level (old rats, 72+/-6 mg/dl; old rats + NO-1886, 142+/-6 mg/dl, P < 0.001) in old rats, but had no effects on plasma glucose or insulin. The endothelium-dependent relaxation of the thoracic aorta caused by histamine was significantly impaired in old rats (% relaxation at 10(-5.5) M histamine: young rats 25.4+/-3.1%; old rats 14.1+/-1.9%, P < 0.01), an effect completely prevented by NO-1886 (old rats + NO-1886; 22.8+/-2.8%, P < 0.05 vs. old rats). In contrast, NO-1886 showed no effect on the endothelium-independent relaxation by sodium nitroprusside. These results indicate that NO-1886 improves impaired endothelium-dependent relaxation of rat aorta associated with aging, possibly by correcting lipid metabolism.


Annals of Nutrition and Metabolism | 1998

Respiratory Quotient in Patients with Non-Insulin-Dependent Diabetes mellitus Treated with Insulin and Oral Hypoglycemic Agents

Yutaka Nakaya; Masaharu Ohnaka; Sadaichi Sakamoto; Yasuharu Niwa; Kazuko Okada; Masahiro Nomura; Tsutomu Hara; Masataka Kusonoki

The respiratory quotient (RQ) reflects the amount of energy derived from carbohydrate as apposed to fat metabolism. To assess the metabolic state of patients with non-insulin-dependent diabetes mellitus, the RQ was measured five times a day (at 09.00, 11.00, 13.00, 14.00, and 17.00 h) in 20 healthy subjects and 60 diabetic patients. Diabetic patients treated with insulin or sulfonylurea showed significantly higher RQ values than normal subjects and nontreated diabetic patients. Diabetic patients without treatment showed higher glucose levels, and their RQ values were significantly lower than those of treated patients. There was a significant inverse correlation between RQ and blood glucose levels at 11.00 h (r = –0.361, p < 0.01) in diabetic patients, but no significant relation with HbA1c. Treated diabetic patients with a higher body mass index tended to show a higher RQ than those with a lower one (r = –0.269, p = 0.083). Within 1 year, 7 of 13 patients, who had RQ > 1.0, gained more than 3 kg, while only 5 of the remaining 32 treated diabetic patients gained more than 3 kg (p < 0.05). This demonstrates that diabetic patients with a higher RQ tended to gain weight despite the use of insulin or oral hypoglycemia agents. The RQ increased by infusing both insulin and glucose in normal subjects. These results suggest that a high RQ results from excess insulin and excess food. The RQ is a good predictor of weight gain in diabetic patients treated with either insulin or oral hypoglycemic agents.


Metabolism-clinical and Experimental | 2000

Effect of the lipoprotein lipase activator NO-1886 on adriamycin-induced nephrotic syndrome in rats

Kaori Nakayama; Tsutomu Hara; Masataka Kusunoki; Kazuhiko Tsutsumi; Asako Minami; Kazuko Okada; Sadaichi Sakamoto; Masaharu Ohnaka; Tetsuro Miyata; Takao Nakamura; Takanari Aoki; Atsushi Fukatsu; Yutaka Nakaya; Shinichi Kakumu

Hyperlipidemia associated with nephrotic syndrome may play a role in the deterioration of renal function. Tsutsumi et al have previously reported that the novel compound NO-1886 increases lipoprotein lipase (LPL) activity, resulting in a reduction of plasma triglycerides and an elevation of high-density lipoprotein (HDL) cholesterol in normal rats. The aim of this study was to ascertain whether NO-1886 suppresses the renal injury by treatment of the hyperlipidemia in an Adriamycin (Kyowa Hakko Kogyo, Tokyo, Japan) induced nephrosis rat model fed a high-protein diet that induced renal dysfunction and tubulointerstitial injury. Administration of Adriamycin caused hyperlipidemia, proteinuria, and edema with ascites in rats in 4 weeks. Furthermore, a combination of Adriamycin and a high-protein diet increased plasma creatinine and blood urea nitrogen (BUN) and decreased plasma albumin. Histologically, in Adriamycin-treated rats, marked interstitial cellular infiltration, tubular lumen dilation, and tubular cast formation in the kidney were observed. NO-1886 decreased plasma triglyceride and increased HDL cholesterol in Adriamycin-induced nephrotic rats. NO-1886 treatment reduced plasma creatinine and BUN levels and increased plasma albumin in Adriamycin-treated rats; it also ameliorated the ascites and proteinuria. Histologically, NO-1886-treated rats showed a quantitatively significant preservation of tubulointerstitial lesions. These data suggest that NO-1886 may have a protective effect against Adriamycin-induced nephrosis with tubulointerstitial nephritis in rats by a modification of the plasma lipid disorder.


Atherosclerosis | 2004

Endothelin-1(1–31) levels are increased in atherosclerotic lesions of the thoracic aorta of hypercholesterolemic hamsters

Kazuaki Mawatari; Sae Kakui; Nagakatsu Harada; Takamasa Ohnishi; Yasuharu Niwa; Kazuko Okada; Akira Takahashi; Keisuke Izumi; Yutaka Nakaya


Journal of Nutritional Science and Vitaminology | 2001

The Nutritional Status of Elderly Bed-ridden Patients Receiving Tube Feeding

Kazuko Okada; Hisashi Yamagami; Seizo Sawada; Miwako Nakanishi; Masaharu Tamaki; Masaharu Ohnaka; Sadaichi Sakamoto; Yasuharu Niwa; Yutaka Nakaya


Journal of Nutritional Science and Vitaminology | 1992

Protein and Energy Metabolism in Patients with Progressive Muscular Dystrophy

Kazuko Okada; Sachinobu Manabe; Sadaichi Sakamoto; Masaharu Ohnaka; Yoshiaki Niiyama


Journal of Nutritional Science and Vitaminology | 2003

Decreased Blood Levels of Lactic Acid and Urinary Excretion of 3-Methylhistidine after Exercise by Chronic Taurine Treatment in Rats

Sachinobu Manabe; Ikuyo Kuroda; Kazuko Okada; Masaki Morishima; Miki Okamoto; Nagakatsu Harada; Akira Takahashi; Kentaro Sakai; Yutaka Nakaya


Biological & Pharmaceutical Bulletin | 2001

Exercise improved accumulation of visceral fat and simultaneously impaired endothelium-dependent relaxation in old rats.

Kazuhiko Tsutsumi; Masataka Kusunoki; Tsutomu Hara; Kazuko Okada; Sadaichi Sakamoto; Masaharu Ohnaka; Yutaka Nakaya

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Tsutomu Hara

Royal Prince Alfred Hospital

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