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  • Electronic Resource  (8)
  • Osteoporosis  (4)
  • Polymer and Materials Science  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Ultrasound bone densitometry of the os calcis in Japanese women (1994)
    Springer
    Osteoporosis international 4 (1994), S. 220-225 
    Details
    ISSN: 1433-2965
    Keywords: Calcaneus ; Dual X-ray absorptiometry ; Menopause ; Osteoporosis ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The velocity (SOS), attenuation slope (BUA) and stiffness index in the os calcis were measured using the ‘Achilles’ ultrasound bone densitometer (Lunar, Madison, WI). We evaluated the basic attributes of this ultrasound bone densitometer, and showed the age-related changes in ultrasound values in normal Japanese women. The precision was measured in vivo on ten occasions over a 2-week period in 5 subjects. The short-term precision errors (CVs) in vivo were 0.6% for stiffness index, 0.3% for SOS and 1.0% for BUA. Spine, femur neck and total body BMD using dual X-ray absorptiometry (DXA) were highly correlated with stiffness index (r=0.80, 0.77 and 0.78, respectively) in 194 subjects. Ultrasound values for patients with osteoporosis were significantly lower than those for the normal controls. TheZ-score compared with young normals was significantly higher for spine bone mineral density (−4.4) than for stiffness index (−3.5); BUA and SOS gave significantly lowerZ-scores −2.9 and −3.0, respectively). Ultrasound values were also lower compared with age-matched normal controls. TheZ-score for stiffness index (−2.1) was significantly superior to that for either SOS or BUA (−1.5). Age-related change in ultrasound values was evaluated in 842 normal women. There was a decline in stiffness index of about 24% from the values in young adulthood to those of women in their seventies, about 75% of which occurred from age 44–49 years onward. These findings seem to indicate that the menopause affected the change in ultrasound values. In conclusion, ultrasound bone densitometry may not be as useful as DXA of the spine for screening for osteoporosis, since theZ-score for DXA is excellent. However, ultrasound bone densitometry appears potentially to be applicable to problems in the diagnosis and management of osteoporosis when used in association with DXA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01623242
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  • 2
    Electronic Resource
    Electronic Resource
    Volumetric bone mineral density using peripheral quantitative computed tomography in Japanese women (1997)
    Springer
    Osteoporosis international 7 (1997), S. 195-199 
    Details
    ISSN: 1433-2965
    Keywords: Bone mineral density ; Osteoporosis ; Quantitative computed tomography ; Radius
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present study evaluated a commercial device for peripheral quantitative computed tomography (pQCT) and examined the age-related changes in normal Japanese women. The volumetric bone mineral density (vBMD) of the distal radius [integral bone mineral density (BMDI), trabecular bone mineral density (BMDT) and cortical with subcortical bone mineral density (BMDSC)] was measured using pQCT (Norland-Stratec XCT960) in 617 healthy women aged 20–79 years and 75 subjects with osteoporosis aged 60–89 years who exhibited at least one vertebral fracture. The short-term precision errors in vivo (CV, %) were 1.1% for BMDI 1.1% for BMDT and 1.2% for BMDSC. The correlations between pQCT and dual-energy X-ray absorptiometry measurements (Lunar DPX) of the lumbar spine werer∼0.8 (BMDI, BMDT and BMDSC). The maximal mean vBMD values were observed between 20 and 49 years; BMDI BMDT and BMDSC all showed a linear postmenopausal decline averaging 1.1% per year. The overall decreases in vBMD from the peak values in those 70–79 years were 34%, 32% and 33% in BMDI, BMDT and BMDSC, respectively. The diagnostic sensitivity of osteoporosis was expressed as aT-score.T-scores using pQCT were −3.0 (BMDI), −2.4 (BMDT) and −2.9 (BMDSC). Bone mineral measurement of the distal radius may be useful in the evaluation of age-related bone loss and for the diagnosis of osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01622288
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  • 3
    Electronic Resource
    Electronic Resource
    Metacarpal bone mass in normal and osteoporotic Japanese women using computed X-ray densitometry (1994)
    Springer
    Calcified tissue international 55 (1994), S. 324-329 
    Details
    ISSN: 1432-0827
    Keywords: Photodensitometry ; Radiogrammetry ; Metacarpal bone ; Bone mineral density ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The metacarpal bone mineral density (BMD) and metacarpal index (MCI) of the second metacarpal bone were measured by computed X-ray densitometry (CXD) (Teijin Ltd., Tokyo), which we have established with the development of microdensitometry of radiographs. In this study, we evaluated the basic attributes of this CXD method and determined the age-related changes in both metacarpal measurements in normal Japanese women. The precision in vivo was measured in eight subjects. The precision errors [coefficient of variation (CV)] were 0.2–1.2% CV for metacarpal BMD and 0.4–2.0% CV for MCI, respectively. We have obtained low precision error and more rapid analysis, within 3 minutes respectively, compared with the previous methods. Age-related changes in the metacarpal measurements were evaluated in 1438 normal women. Both measurements showed the most significant decrease in the sixth decade of life. The rate of decrease in the sixth decade was 1.6%/year for metacarpal BMD and 1.5%/year for MCI. On comparison between metacarpal BMD by CXD and spine BMD using dual energy X-ray absorptiometry (DXA) in 248 normal women with and without menstruation, the two measurements were found to be similarly decreased in the subjects within 5 years after menopause. There was also no significant difference in the Z-score between metacarpal BMD and spine BMD within 5 years after menopause. These results indicate that early postmenopausal bone loss occurs not only in the spine but also in the metacarpal bone. The metacarpal BMD for patients with osteoporosis was significantly lower than that for age-matched normal controls, although the Z-score for spine BMD (-1.46) was significantly better than that for metacarpal BMD (-0.82). In conclusion, because CXD has excellent low precision error and is widely available at relatively low cost, it appears potentially to be applicable to problems in the diagnosis and management of osteoporosis, when used in association with DXA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299308
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  • 4
    Electronic Resource
    Electronic Resource
    Factors influencing vertebral bone density after renal transplantation (2000)
    Springer
    Transplant international 13 (2000), S. S431 
    Details
    ISSN: 1432-2277
    Keywords: Key words Bone mineral density ; Hyperparathyroidism ; Osteoporosis ; Renal transplantation ; Steroid therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To improve our understanding of the mechanisms underlying osteoporosis following renal transplantation, we compared bone mineral density (BMD) in 158 transplant recipients and in 293 patients undergoing maintenance hemodialysis with age- and sex- matched normal controls. Observations in graft recipients were made up to several years following transplantation. Dual-energy X-ray absorptiometry was used to measure BMD. Correlations with clinical variables including serum concentration of parathyroid hormone (PTH) and steroid therapy were evaluated. Lumbar BMD was lower in transplant patients than in dialysis patients at all ages, and continued to decrease with increasing interval posttransplant until the second year after transplantation. Persistent hyperparathyroidism and daily prednisolone dosage were both associated with decreased BMD. Age and creatinine clearance were independent long-term predictors of BMD by multiple regression analysis. Treatment of renal graft recipients with calcium and vitamin D supplements or calcitonin may be indicated in the early months after transplantation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001470050377
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of the surface geometry of smooth and porous-coated titanium alloy on the orientation of fibroblasts in vitro (1987)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 21 (1987), S. 107-126 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The migration and orientation of human gingival fibroblasts in relation to the rim of smooth-surfaced and porous-coated titanium discs placed on multilayers in vitro was investigated. Samples were examined after 6 h, 24 h, 3 days, and 7 days of culture using phase-contrast and scanning electron microscopy. The cells migrated from the multilayer onto the smooth-surfaced discs forming bridges between them, and orientated along parallel circumferential grooves in the rim of the discs. This resulted in the cellular bridges orientating at an acute angle to the rim of the disc, and adjacent cells in the multilayer orientating parallel to the rim. Cellular bridges were also formed between the porous-coated discs and the multilayer but, because the cells that migrated onto, and between, the spheres of the porous-coat showed no preferred orientation, the bridges retained their orientation at right angles to the surface of the rim. This in turn resulted in the cells of the adjacent multilayer becoming similarly orientated. These observations suggest that the geometrical configuration of the surface of implants could influence whether a capsule or an orientated fibrous attachment is developed in relation to implants in vivo.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820210114
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  • 6
    Electronic Resource
    Electronic Resource
    Morphology of banded spherulites in poly(ε-caprolactone)/poly(styrene-ran-acrylonitrile) blends (1997)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 48 (1997), S. 354-362 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The occurrence of banded spherulites in blends of poly(ε-caprolactone) with poly(styrene-ran-acrylonitrile) is studied by means of optical-, scanning electron-, environmental scanning electron-, and atomic force-microscopy as well as smallangle X-ray scattering. The measurements reveal that lamellae are confined in fibrils that bend periodically from the center of spherulites in a radial direction. The fibrils show also a regular spacing in the lateral direction. Single bent lamellae can be observed by atomic force microscopy after permanganic etching. The enrichment of amorphous material near to the growth front of the spherulites can be directly observed by polarized light microscopy after temperature jump experiments. The excluded amorphous material on the surface of the growing spherulites has the shape of droplets. This might be the main reason for the initiation of the bending process because the result is a non-uniform stress distribution acting on the growing lamellae at the interface between spherulites and the surrounding melt. The amorphous material of the blends can be found in three areas as observed by small-angle X-ray scattering experiments and microscopical methods: (i) between the lamellae, (ii) excluded from the interlamellar region but within the spherulite, and (iii) for high contents of non-crystallizable material, it can be excluded from the spherulite. The banding periodicity of spherulites as a function of the crystallization temperature can be described in terms of two models, based either (i) on the inherent twisting of lamellae perpendicular to the axis of a screw dislocation or (ii) on the dependence of the diffusion of amorphous material away from the growth front of lamellae and the temperature dependence of the rate of crystallization. Both models fail at very low supercoolings near to temperatures where the banding disappears completely.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1997.010480902
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  • 7
    Electronic Resource
    Electronic Resource
    Evaluation of equation-of-state parameters from PVT data (1995)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 46 (1995), S. 312-318 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The characteristic parameters for three different equation-of-state (EOS) theories have been determined for polystyrene and low-molecular weight polyisoprene using pressure-volume-temperature (PVT) data. Basically two procedures for the calculation of characteristic parameters were applied. The characteristic parameters were calculated, firstly, from coefficients of expansion, compressibilities and densities, and secondly, by fitting the corresponding EOS to PVT data minimizing the sum of the squares of the differences between experimental and calculated pressures. The characteristic parameters obtained by the two methods are compared with regard to their ability to describe PVT data. A comparison of the three different EOS theories reveals that, for describing polymeric liquids, the modified cell model of Dee and Walsh is superior to the theory of Flory, Orwoll and Vrij as well as to the lattice fluid theory of Sanchez and Lacombe. Finally, formulae are given to convert the characteristic parameters from one theory into those of another.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1995.010460405
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  • 8
    Electronic Resource
    Electronic Resource
    Evaluation of equation-of-state parameters and the description of PVT-data (1996)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 47 (1996), S. 520-524 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: For three different equation-of-state theories the characteristic parameters of two polymers were calculated, and the ability of the theories to describe PVT-data using these parameters was investigated. The comparison between the different theories shows that, concerning the description of PVT-data, the modified cell model of Dee and Walsh is not only superior to the theory of Flory, Orvoll and Vrij and that of Sanchez and Lacombe as reported before, but also to the theory of Simha and Somecynsky and the open cell model of Zhong, Wang and Lu. Finally, simple formulae are given to calculate the characteristic parameters of the latter two theories from those of the theory of Flory, Orwoll and Vrij.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1996.010471108
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