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Menadione-induced cytotoxicity to rat osteoblasts (1997)

Sun, J.-S. ; Tsuang, Y.-H. ; Huang, W.-C. ; [et al.]

Springer

Cellular and molecular life sciences 53 (1997), S. 967-976

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ISSN: 1420-9071

Keywords: Key words. Menadione; oxidative stress; osteoblasts; superoxide dismutase (SOD); catalase.

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract. Oxygen-derived free radical injury has been associated with several cytopathic conditions. Oxygen radicals produced by chondrocytes is an important mechanism by which chondrocytes induce matrix degradation. In the present study, we extend these observations by studying oxidative processes against osteoblasts. Osteoblasts were mixed in in vitro culture with 200 μM menadione. The cytotoxic effect of menadione-induced oxidative stress was monitored by lucigenin- or luminol-amplified chemiluminescence, tetrazolium assay and immunocytochemical study. Results showed that adding menadione induces an oxidative stress on osteoblasts, via superoxide and hydrogen peroxide production, that can be eradicated by superoxide dismutase (SOD) and catalase in a dose-dependent manner. Catalase and the appropriate concentration of dimethyl sulfoxide have a protective effect on cytotoxicity induced by menadione, whereas SOD does not. Menadione-treated osteoblasts have a strong affinity for annexin V, and the nuclei are strongly stained by TUNEL (TdT-mediated dUTP nick-end labelling). The results suggest that menadione-triggered production of reactive oxygen species leads to apoptosis of osteoblasts.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s000180050118

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Differential Effects of Bone Mineral Content and Bone Area on Vertebral Strength in a Swine Model (1998)

Yang, R.-S. ; Wang, S.-S. ; Lin, H.-J. ; [et al.]

Springer

Calcified tissue international 63 (1998), S. 86-90

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ISSN: 1432-0827

Keywords: Key words: Bone mineral content — Vertebral bone area — Compressive stress — Failure load — Stored strain energy.

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract. Since the biomechanical competence of a vertebral body may be closely related to the content and distribution of the bone mineral, we have evaluated the effects of projected vertebral bone area (BA) and bone mineral parameters [bone mineral content (BMC) or bone mineral density (BMD)] on their biomechanical competence. We used dual-energy X-ray absorptiometry (DXA) to assess the bone mineral parameters of 36 swine thoracic vertebrae (T1–T12) and 15 lumbar vertebrae (L1–L5) after removal of the posterior elements. The failure load, compressive stress, and the stored strain energy of these vertebral bodies were assessed by a uniaxial compressive test using an MTS 810 testing system. Multiple regression analysis showed a significantly negative effect of BA and significantly positive effect of BMC on the biomechanical competence (compressive stress, r2= 0.67, P 〈 0.0001; failure load, r2= 0.75, P 〈 0.0001). However, the stored strain energy was only related to the BMC (r2= 0.35, P 〈 0.0001). The contributory effects of BMC and BA on the biomechanical competence were not equal. The effects of BMC was larger than BA in determining the failure load and stored strain energy, whereas the reverse was found for the compressive stress. Using the log-transformed parameters as the regressors resulted in similar results. These results suggested the differential effects of BA and BMC in determining the biomechanical competence of vertebral bodies. We recommend the use of both parameters instead of BMD alone for evaluation of the vertebral biomechanical competence.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002239900494

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Factor of Risk for Hip Fracture in Normal Chinese Men and Women in Taiwan (1999)

Yang, R. S. ; Liu, T. K. ; Hang, Y. S. ; [et al.]

Springer

Calcified tissue international 65 (1999), S. 422-426

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ISSN: 1432-0827

Keywords: Key words: Factor of risk (Φ) — Hip fracture — Chinese — Bone mineral density — Bone area.

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract. We have investigated the age-related change in factor of risk (Φ) for the proximal femoral load during free fall in 548 females and 240 males aged 21–79 years. These individuals were divided into either young (age 〈50 years) or old group (age ≥50 years). Another 26 females with hip fractures were included for comparison. The bone mineral density (BMD) of proximal femoral neck was measured by a Norland XR-26 dual-energy X-ray absorptiometer (DXA). The estimated fracture load (L) of femoral neck was calculated from the BMD with the regression equation derived by Courtney et al. [2,3] and estimated fall force (F) by body weight and height according to the regression equation derived by Nakamura et al. [6] respectively. Φ was defined as the quotient of F/L. The results showed an age-related decrease of BMD (P 〈 0.001) in both genders corrected for weight and height. By multiple linear regression analysis, the F decreased significantly with aging corrected for BMD in old males (partial r =−0.255, P 〈 0.01) and increased with aging in all females (young, partial r=0.287, p 〈 0.001; old, partial r = 0.252, P 〈 0.001). L decreased significantly with aging corrected for height and weight in males (young, partial r =−0.401, P 〈 0.01; old, partial r =−0.178, P 〈 0.05) and females (young, partial r =−0.168, P 〈 0.05; old, partial r =−0.459, P 〈 0.001). However Φ decreased with aging in young males (P 〈 0.01) and females (young: P 〈 0.001, old: P 〈 0.001). Φ increased in old women but not in old men, and was higher in old women compared with old men. The 26 patients with hip fractures had a significantly higher Φ value than 85 age-matched women. In conclusion, Φ may provide a comprehensive comparison of the risk of hip fracture in the elderly population.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002239900727

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In vitro and in vivo mechanical evaluations of plasma-sprayed hydroxyapatite coatings on titanium implants: The effect of coating characteristics (1997)

Yang, C. Y. ; Lin, R. M. ; Wang, B. C. ; [et al.]

Hoboken, NJ : Wiley-Blackwell

Journal of Biomedical Materials Research 37 (1997), S. 335-345

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ISSN: 0021-9304

Keywords: bonding-strength ; shear-strength ; simulated body fluid ; push-out measurement ; Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Medicine , Technology

Notes: This study was undertaken to evaluate the effect of coating characteristics on the mechanical strengths of the plasma-sprayed HA-coated Ti-6Al-4V implant system both in vitro and in vivo. Two types of HA coatings (HACs) with quite different microstructures, concentrations of impurity-phases, and indices-of-crystallinity were used. In vitro testings were done by measuring the bonding-strength at the Ti-6Al-4V-HAC interface, with HACs that had and had not been immersed in a pH-buffered, serum-added simulated body fluid (SBF). The shear-strength at the HAC-bone interface was investigated in a canine transcortical femoral model after 12 and 24 weeks of implantation. The results showed a bonding degradation of approximately 32% or higher of the original strength after 4 weeks of immersion in SBF, and this predominantly depended on the constructed microstructure of the HACs. After the push-out measurements, it was demonstrated that the HACs with higher bonding-strength in vitro would correspondingly result in significantly higher shear-strength at each implant period in vivo. Nevertheless, there were no substantial histological variations between the two types of HACs evaluated. The most important point elucidated in this study was that, among coating characteristics, the microstructure was the key factor in influencing the mechanical stability of the HACs both in vitro and in vivo. As a consequence, a denser HAC was needed to ensure mechanical stability at both interfaces. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 335-345, 1997.

Additional Material: 9 Ill.

Type of Medium: Electronic Resource

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