Sadahiko Nozaki

Nihon University, Edo, Tokyo, Japan

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Publications (8)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.
    No preview · Article · Feb 2003 · Journal of Bone and Mineral Metabolism
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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.
    Preview · Article · Jul 2001 · Journal of Occupational Health
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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.
    No preview · Article · Feb 2000 · Journal of Bone and Mineral Metabolism

  • No preview · Article · Jan 1999 · Japanese Journal of Health and Human Ecology
  • Hisayuki Tsuchiya · Takeo Miyake · Eise Yokoyama · Sadahiko Nozaki

    No preview · Article · Jan 1998 · Japanese Journal of Health and Human Ecology
  • Hisayuki Tsuchiya · Takeo Miyake · Eise Yokoyama · Sadahiko Nozaki

    No preview · Article · Jan 1997 · Japanese Journal of Health and Human Ecology
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    ABSTRACT: The largest nationwide active surveillance of four Measles-Mumps-Rubella (MMR) vaccines was conducted in Japan. A total of 1255 pediatricians actively participated in the study, which comprised 8.6% of all members of the Japanese Pediatric Society. The total number of registered recipients of MMR vaccines was 38 203. They were arbitrarily given one of the MMR vaccines produced by three makers (Takeda, Osaka city, Kitasato Minato-ku. Tokyo and Biken Suita city, Japan) or the standard MMR vaccine made of designated strains (Kitasato's measles-AIK-C, Biken's mumps-Urabe Am9 and Takeda's rubella-To336) produced by Takeda, Kitasato and Biken and were observed for 35 days. The rates of virologically confirmed aseptic meningitis per 10,000 recipients were 16.6, 11.6, 3.2 and 0 for the standard MMR, Takeda MMR, Kitasato MMR and Biken MMR vaccines, respectively. The incidence of convulsions between 15 and 35 days was the highest with the standard MMR vaccine and the incidence of fever associated with vomiting occurring between 15 and 35 days (symptoms relevant to aseptic meningitis) were also the highest with the standard MMR vaccine. The incidence of parotid swelling was the lowest with Takeda MMR vaccine. This surveillance revealed that incidences of aseptic meningitis after administration of the standard MMR vaccine and of Biken MMR vaccine were different. This posed questions about the manufacturing consistency of the Urabe Am9 mumps virus vaccines. On the other hand, the National Institute of Health found that the biological characteristics of the Urabe Am9 mumps virus contained in the standard MMR vaccine and in the Biken MMR vaccine were different. The Biken Company reported that the mumps vaccine in the standard MMR vaccine was a mixture of two Urabe Am9 mumps vaccine bulks; one identical to that contained in the Biken MMR vaccine and the other produced by a different manufacturing process.
    No preview · Article · Jul 1996 · Acta paediatrica Japonica; Overseas edition
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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.
    Preview · Article · Jan 1996