Sadahiko Nozaki

Nihon University, Edo, Tōkyō, Japan

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Publications (7)6.03 Total impact

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    ABSTRACT: Osteoporosis caused by exposure to microgravity represents a serious clinical concern, but the mechanisms have yet to be fully elucidated. The present research aimed to elucidate the effects of microgravity environments on bone turnover, with a specific focus on changes in bone resorption markers such as type I collagen cross-linked N-telopeptides (NTx) and deoxypyridinoline (Dpyr), for which scant data are available regarding detailed time course. Methods using 6 degrees head-down bed rest were utilized to simulate a microgravity environment. Eleven adult male volunteers underwent 6 degrees head-down bed rest for 14 days; measurements were made of serum and urine Ca concentrations, in addition to osteocalcin (OC), bone alkaline phosphatase (ALP), NTx, and Dpyr as bone turnover markers. By the end of bed rest, concentrations of bone ALP had significantly increased, but OC displayed a tendency toward decrease. Concentrations of Dpyr significantly increased from day 6, remaining elevated until the end of bed rest. Concentrations of NTx significantly increased on day 13 and at the end of bed rest. Serum and urinary concentrations of Ca increased significantly at the end of bed rest. Bone ALP represents a relatively early marker of osteoblast differentiation at the matrix maturation phase and OC is a late marker in osteoblast differentiation at the calcification phase. The present results therefore suggest an absolute increase in bone resorption and normal or reduced bone formation, together causing prominent uncoupling and rapid bone loss after simulated microgravity. Moreover, the present results suggest that bone resorption is enhanced at an early stage of exposure to microgravity environments.
    Journal of Bone and Mineral Metabolism 02/2003; 21(5):311-5. DOI:10.1007/s00774-003-0426-6 · 2.46 Impact Factor
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    Fumi TAKEDA · Eise YOKOYAMA · Takeo MIYAKE · Sadahiko NOZAKI
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    ABSTRACT: Based on the data for 382 nursery teachers and instructors in 71 facilities for mentally retarded children, we studied occupational factors related to burnout in staff of facilities for mentally retarded children. As the result of stepwise multiple regression analysis, burnout scores were significantly related to "work burden", "work satisfaction", "dissatisfaction with effectiveness of treatment/instruction", "emotional support", and "aversion to dealing with children". The lower scores in "work satisfaction" and "emotional support" and the higher scores in "work burden", "aversion to dealing with children", and "dissatisfaction with effectiveness of treatment/instructions" resulted in the higher burnout scores. These results suggest that it is important to improve the organizational working, support, and training systems.
    Journal of Occupational Health 07/2001; 43(4):173-179. DOI:10.1539/joh.43.173 · 1.11 Impact Factor
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    ABSTRACT: To prevent osteoporosis, which is expected to increase in incidence in this rapidly aging society, in recent years bone mineral density (BMD) has frequently been measured as a predisposition index. However, these measurements are made on different sites with different apparatus, and the results are independently studied by different institutions. In our present investigation, to establish the standard radius BMD as determined by dual-energy X-ray absorptiometry (DXA), we carried out a general population survey in 29 municipalities and prefectures on 11,252 locally residing females aged 15 to 83 years (mean, 35.61 +/- 12.85 years). Their YAM (young adult mean) BMD was estimated at 0.664 +/- 0.054 g/cm2, which was almost the same as the figure given in the 1996 version of the diagnostic criteria for primary osteoporosis. We further studied the relationships of BMD to age and physical factors known to be influential to BMD. It was found that BMD was correlated negatively to age and positively to body mass index (BMI). The average values we obtained for age and physique groups appeared to have provided reliable indices for the primary prevention of osteoporosis.
    Journal of Bone and Mineral Metabolism 02/2000; 18(1):31-5. DOI:10.1007/s007740050007 · 2.46 Impact Factor
  • Japanese Journal of Health and Human Ecology 01/1999; 65(6):273-281. DOI:10.3861/jshhe.65.273
  • Hisayuki Tsuchiya · Takeo Miyake · Eise Yokoyama · Sadahiko Nozaki
    Japanese Journal of Health and Human Ecology 01/1998; 64(5):313-325. DOI:10.3861/jshhe.64.313
  • Hisayuki Tsuchiya · Takeo Miyake · Eise Yokoyama · Sadahiko Nozaki
    Japanese Journal of Health and Human Ecology 01/1997; 63(4):241-253. DOI:10.3861/jshhe.63.241
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    ABSTRACT: Twenty cases of rectal carcinoid were reviewed, which were treated with endoscopic resections at our hospital from October 1989 to April 1996. The mean age of patients was 55 years (range 27-80) . The ratio of men to women was 0.54 : 1 (=7 : 13) . The size of the tumors were less than 5mm in diameter in 6 cases and 5-8mm in 14 cases. The locations of the lesions were the upper rectum (Ra) in 4 cases and the lower rectum (Rb) in 16 cases. The depth of the tumors were submucosal layer in all cases. For the initial treatments snare polypectomies were done in 9 cases, endoscopoic mucosal resections (EMR) in 4 cases and hot biopsies in 7 cases. In 8 cases (40%) the lesions were completely resected without recurrences. But in 12 cases cut-end were positive with tumors. By follow-up study, no residual lesions were seen in 8 cases (40%) because of burning effects. But in 2 cases residual lesions were recognized histopathologically. Both cases were treated with hot biopsies initially. In the other 2 cases no follow-up study has been done yet. The rate of cut-end positive cases was high (6/7=86%) by hot biopsy technique, and there was the risk of residual lesions. So we recommend snare polypectomy or EMR for the initial endoscopic treatment of rectal carcinoids.
    01/1996; 49:172-173. DOI:10.11641/pdensks.49.0_172