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  • 1
    Electronic Resource
    Electronic Resource
    Age-related changes in os calcis ultrasonic indices: A 2-year prospective study (1995)
    Springer
    Osteoporosis international 5 (1995), S. 478-483 
    Details
    ISSN: 1433-2965
    Keywords: Aging ; Bone loss ; Bone mineral density ; Broadband ultrasound attenuation ; Speed of sound ; Stiffness index ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed repeated ultrasound measurements approximately 2 years apart (average 23 months ±3 months) on the os calcis of 113 healthy postmeno-pausal women recruited from two large prospective cohort studies named OFELY and EPIDOS. Group A (from OFELY) consisted of 88 women aged 52–72 (63±5) years, randomly selected from a large insurance company, and group B (from EPIDOS) consisted of 25 women aged 75–88 (80±4) years, randomly selected from the voting lists. We obtained broadband ultrasonic attenuation (BUA) and speed of sound (SOS) measurements, as well as the Stiffness index, with a Lunar Achilles ultrasound machine. We performed dual energy X-ray absorptiometry (DXA) measurements of femoral neck bone mineral density (neck BMD) with a Hologic QDR 2000 for group A and with a Lunar DPX Plus for group B. The decrease that we observed over 2 years was on average ±1 SD: −1.01±4.6 dB/MHz (p=0.02) for BUA (which is approximately equal to the long-term precision error in vitro), −11.3±9.2 m/s (p=0.0001) for SOS (approximately 5 times the precision error), −3.8±4.2 %YA (p=0.0001) for Stiffness (2.5 times the precision error) and −0.01±0.03 g/cm2 (p=0.0001) for neck BMD (approximately equal to the precision error). In terms of percentage change this represents: −1.0%±4.3% for BUA, −0.8%±0.6% for SOS and −1.85%±4.4% for neck BMD. At the individual level, most SOS and Stiffness values were consistent with a decrease, whereas BUA and neck BMD values were spread out above and below the zero line of no change. The decreases in SOS and Stiffness were significantly larger in the early postmenopause (⩽20 years since menopause [YSM]) than in the late postmenopause (〉20 YSM). We observed a similar trend for BUA and BMD but this did not reach statistical significance. We found a weak but significant correlation between changes in ultrasound variables and changes in neck BMD. However, the 2-year changes observed in SOS were not significantly correlated with changes in BUA. This study suggests that the heel ultrasound measurements of SOS and Stiffness are valuable indices of postmenopausal bone loss, and could be used for follow-up in therapeutic trials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01626612
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  • 2
    Electronic Resource
    Electronic Resource
    Trabecular and endocortical bone remodeling in postmenopausal osteoporosis: Comparison with normal postmenopausal women (1990)
    Springer
    Osteoporosis international 1 (1990), S. 41-49 
    Details
    ISSN: 1433-2965
    Keywords: Bone ; Histomorphometry ; Osteoporosis ; Osteoblasts ; Osteocalcin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To assess the bone turnover abnormalities which characterize postmenopausal osteoporosis with vertebral fractures (PMOp), a transiliac bone biopsy was performed after double labeling of the mineralizing front with tetracycline in 50 untreated PMOp patients who were compared with 13 healthy age-matched volunteer females. The analysis of bone remodeling and structure parameters demonstrated that PMOp is a disease affecting both the cancellous and the endocortical envelopes and characterized by increased resorption and by a marked decrease in the osteoblastic apposition rate due to a reduced duration of bone formation. This induces a decrease in the width of both individual osteons and trabeculae. In PMOp, the wide spectrum of bone turnover as compared with the controls, associated with the typical bimodal distribution of cancellous osteoid perimeter, allowed us to identify two subsets, one with normal turnover (NT) and one with high turnover (HT) representing 30% of the cases. When compared to NT, HT was characterized by increased osteoclast number, lower bone volume, thinner osteons, increased formation at the tissue-level and markedly decreased duration of formation. In HT the marked decrease in the duration of activity of osteoblasts and the markedly increased number of osteoclasts induced a greater decrease in bone volume, despite the increase of bone formation at the tissue level. These subsets could not be distinguished by any clinical or biochemical parameter except for serum bone gla protein (osteocalcin) which was significantly higher (as a group) in HT than in NT. The underlying cause for these two subsets is unknown. We conclude that PMOp affects the cancellous and the endocortical bone. Bone loss results from a wide spectrum of bone turnover abnormalities, with two distinct subsets, one with normal turnover and one with high turnover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01880415
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Glucocorticoid-induced inhibition of osteoblastic bone formation in ewes: A biochemical and histomorphometric study (1993)
    Springer
    Osteoporosis international 3 (1993), S. 97-102 
    Details
    ISSN: 1433-2965
    Keywords: Bone formation ; Ewes ; Glucocorticoids ; Histomorphometry ; Osteocalcin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mechanisms underlying glucocorticoid-induced osteoporosis in humans are a defect in bone formation associated with increased bone resorption. The latter may be due to elevated parathyroid hormone (PTH) levels induced by the impairment of intestinal calcium absorption caused by corticosteroids. In this study we analysed the effects of corticosteroids in old ewes, a potential model for the study of human bone turnover. Two groups of seven 9-year-old female sheep were selected. The first group was injected intramuscularly with a daily dose of 30 mg methylprednisone (MP) during the first 2 months and 15 mg during the last month. After 2 and 3 months of treatment, blood samples were taken. At the end of the experiment the animals were slaughtered and the iliac crest kept for bone histomorphometry. Serum osteocalcin (sOC) rapidly and markedly decreased in the MP-treated group compared with controls (−77%;p〈0.01). In contrast, at the end of the experiment serum calcium and PTH levels were similar in both groups. Histomorphometric analysis showed a significant reduction in the wall width of trabecular packets. Dynamic parameters reflecting bone formation at the tissue and cell levels were significantly lower in the MP-treated group than in controls, with a highly significant decrease in the mineralization rate (MAR: −63%,p〈0.05) and double-labeled perimeter (dLPm/B.Pm: −92%p〈0.05). The bone formation rate (BFR/B.Pm) also decreased by 84% and the adjusted apposition rate (Aj.AR) by 80%. The increase in the total formation period was mainly due to an increase in the inactive period. Significant correlations were found between sOC and MAR, dLPm/B.Pm and BFR/B.Pm (withr′ respectively 0.67, 0.76 and 0.51). In conclusion, the effects of corticosteroid on ewe bone remodeling are essentially characterized by a major bone formation defect without evidence of secondary hyperparathyroidism, although this cannot be totally excluded by our results. Ewes treated with glucocorticoids could represent a good model for evaluating the effects of drugs candidates for all bone conditions characterized by reduced bone formation resulting from osteoblastic depression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01623380
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrasound measurements on the os calcis in a prospective multicenter study (1994)
    Springer
    Calcified tissue international 55 (1994), S. 94-99 
    Details
    ISSN: 1432-0827
    Keywords: Broadband ultrasound attenuation ; Speed-of-sound ; Stiffness index ; Interunit precision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Ultrasonic assessment is a new approach to assess both quality and density. Two ultrasonic parameters are measured on the os calcis: the attenuation or broadband ultrasound attenuation (BUA) and the velocity or speed of sound (SOS). The interunit variations in vitro and in vivo of an ultrasound instrument, the Lunar AchillesR system, used in a French multicenter study named EPIDOS, were calculated and the stability of these intruments over a 12-month period was evaluated. A third parameter called “stiffness index”, calculated from the SOS and BUA, was also used in this study. The average CV in vitro for the BUA and SOS was 0.92% and 0.12%, respectively, and the average CV in vivo for the BUA, the SOS, and the stiffness index was 1.83%, 0.23%, and 1.9%, respectively. The interunit (or inter-machines) variations were calculated by a one-way analysis of variance. We detected small but significant measurement differences among centers on a phantom for both SOS (maximum significant difference 0.4%) and stiffness (maximum significant difference 3.5%) but not for BUA. Similar diffrences were found in vivo. The precision over 12 months of the interunit variations in vitro was evaluated by measuring a single phantom traveling from one center to another several times. The range of the CV for the BUA (1.54–0.51%), for the SOS (0.25–0.14%), and for the stiffness index (2.26–1.10%) are explained in part by technical failures. The variation among the five Achilles was estimated by the combined CV which was 1.42% for the BUA, 0.32% for the SOS, and 2.33% for the stiffness index. In conclusion, our findings indicate that equipment from one manufacturer appears to be consistent between machines for the BUA, but not completely for the SOS. The results for this stiffness index are necessarily influenced by both SOS and BUA. The shortterm and long-term interunit precision is good, both in vitro and in vivo. Such results provide increased confidence in multicenter clinical trials where ultrasonic data are pooled.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297182
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    Paper (German National Licenses)
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