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  • 1
    Electronic Resource
    Electronic Resource
    Mean wall thickness and formation periods of trabecular bone packets in corticosteroid-induced osteoporosis (1983)
    Springer
    Calcified tissue international 35 (1983), S. 410-417 
    Details
    ISSN: 1432-0827
    Keywords: Bone remodeling ; Histomorphometry ; Corticosteroid therapy ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have compared the mean wall thickness (MWT) and active formation periods (sigmaf(A)) of trabecular bone packets in iliac crest biopsies from 20 patients (7 male, 13 female) with corticosteroid-induced osteoporosis (CS-OP) and 20 age- and sex-matched controls. The trabecular bone volume (TBV) of the CS-OP patients (9.6%±2.2% [SD]) was significantly reduced compared to controls (19.3%±5.1%). The MWT of CS-OP patients (32.7±4.3 µm) was also significantly lower than the control value (48.0±6.2 µm). There was a positive correlation between MWT and TBV in both groups. The mineralization rate (M) of the CS-OP patients (0.54±0.25 µm/day) was within the normal range, and since there was no increase in osteoid seam thickness, so therefore was the osteoblastic appositional rate (OAR). The active formation period of trabecular bone packets (sigmaf(A)=MWT/M) was significantly lower in the CS-OP patients (55.9 ± 14.4 days) than in the control group (68.1 ± 9.4 days). MWT and sigmaf(A) both decreased with age in the control group, whereas in the CS-OP group they were independent of age. We conclude that corticosteroid therapy results in a reduction of the MWT of trabecular bone packets and, consequently, of TBV. In these patients, where the OAR was normal, the reduction in MWT was apparently caused by a shortening of the lifespan of the active osteoblastic population at the basic multicellular unit (BMU) level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405069
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  • 2
    Electronic Resource
    Electronic Resource
    Marrow changes in paraplegic patients (1984)
    Springer
    Calcified tissue international 36 (1984), S. 338-340 
    Details
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405340
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  • 3
    Electronic Resource
    Electronic Resource
    Influence of fat on ultrasound measurements of the Os calcis (1994)
    Springer
    Calcified tissue international 54 (1994), S. 91-95 
    Details
    ISSN: 1432-0827
    Keywords: Fat ; Ultrasound attenuation ; Speed-of-sound ; Os calcis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Measurements of the speed-of-sound (SOS) and of the broadband ultrasound attenuation (BUA) on the os calcis were recently proposed to assess osteoporotic fragility. Velocity and attenuation were measured through the heel which can be divided in three phases including hydroxyapatite, soft tissue, and fat. The aim of this study was to evaluate the influence of fat composition and heel width on SOS and BUA. This influence was determined from both in vitro investigations examining fat samples, phantoms, and cadaver heels, and in vivo ones observing adult volunteers as well as a wide sample section of healthy elderly women. Ultrasound velocities on various fat samples were significantly lower than those on distilled water (-65 m/second to -123 m/second). The excision of the surrounding soft tissue from cadaver heels made SOS steadily increase whereas the insertion of a 10 mm piece of lard in the lateral face of cadavers' and volunteers' heels os calcis lowered SOS about 30 m/second. ond. Furthermore, a difference of SOS was estimated at 15 m/second for a 12.5% variation of the marrow fat weight. Among 334 elderly and healthy women aged 75 and over, a significant negative correlation was found between SOS and heel width (r=-0.27; P〈0.0001). On the other hand, fat composition had no significant effect on BUA measurement, and no significant relationship was found between BUA and heel width. This study demonstrates that an increase of heel width and fat thickness provides an underestimation of os calcis SOS, but has no significant effect on BUA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296057
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  • 4
    Electronic Resource
    Electronic Resource
    Fractal Analysis of Bone Texture on Os Calcis Radiographs Compared with Trabecular Microarchitecture Analyzed by Histomorphometry (1998)
    Springer
    Calcified tissue international 63 (1998), S. 121-125 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Fractal analysis—Os calcis—Radiographs—Histomorphometry—Microarchitecture.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Microarchitecture of trabecular bone is an important determinant of bone fragility; to date, its evaluation requires bone biopsy with histomorphometry analysis. Methods of noninvasive characterization of trabecular bone microarchitecture are in development and we have developed and validated a bone texture analysis applied to bone radiographs and based on fractal geometry. The aim of our study was to compare this fractal analysis of trabecular bone texture on radiographs to the trabecular microarchitecture analyzed by bone histomorphometry on os calcis biopsies. Thirty eight ossa calcis from 19 human cadavers were studied. Fractal analysis of the trabecular bone of os calcis radiographs was performed by the maximum likelihood estimator following the fractional brownian motion model. The ossa calcis were dissected, then transcortical biopsy cores focused on the fractal analysis region of interest were obtained. Structural and connectivity parameters were measured with both automatic and semiautomatic analyzers. We have found a significant relationship between the fractal Hmean parameter and structural histomorphometric indices; the best correlation was found with trabecular separation (r =−0.55; P= 0.0004). Based on a stepwise regression analysis, trabecular spacing and trabeculae number together would explain 38% of the variance of the fractal parameter. Although the relationship with connectivity indices was poor, our fractal analysis of os calcis trabecular bone texture on radiographs seemed to partially reflect the trabecular bone microarchitecture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900501
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  • 5
    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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  • 6
    Electronic Resource
    Electronic Resource
    Activity Increase After Extraction of Alkaline Phosphatase from Human Osteoblastic Membranes by Nonionic Detergents: Influence of Age and Sex (2000)
    Springer
    Calcified tissue international 66 (2000), S. 22-28 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Anchored alkaline phosphatase — Detergents — Bone cells — Age.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The solubilization of alkaline phosphatase (AP) from osteoblastic cell membranes obtained from human primary bone cell cultures was studied according to the age and sex of the donors (17 females, 11 males; age range: 2–77 years). Cell membranes were treated by non-ionic (n-octyl β-D-glucopyranoside, OG), ionic or zwitterionic detergents, then centrifuged. When OG was used almost all the AP was solubilized. AP activity in supernatant of solubilization was compared to the activity of the suspension before centrifugation. The activity ratio (AR) increased in function of age for subjects between 65 and 74. Neither total nor specific AP activities were influenced by age or sex. Electrophoresis studies showed that the AP released was a GPI (glycosyl phosphatidylinositol)-anchored protein, amphipatic form, with 140 kDa as apparent molecular mass. The activity change of AP in the presence of OG may result from age-related modifications either in the AP structure or in the constituents of the plasma membranes (proteins or phospholipids).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002230050006
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  • 7
    Electronic Resource
    Electronic Resource
    Mean wall thickness and formation periods of trabecular bone packets in idiopathic osteoporosis (1981)
    Springer
    Calcified tissue international 33 (1981), S. 199-204 
    Details
    ISSN: 1432-0827
    Keywords: Bone remodeling ; Histomorphometry ; Trabecular bone ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mean wall thickness (MWT) and duration of formation periods (sigmaf) of trabecular bone packets have been measured in iliac crest biopsies following double tetracycline labeling from 9 women having primary osteoporosis, with vertebral crush fractures and reduced trabecular bone volume (TBV), and 9 age- and sex-matched controls. The MWT of the osteoporotic biopsies was significantly less than that of the controls and was negatively correlated with age in the latter. There was also a positive correlation between MWT and TBV in the controls but not in the osteoporotics. Sigmaf, in days, showed a tendency to decline with age in the control biopsies and was further decreased in the osteoporotic patients. These results suggest that a major contribution to the negative skeletal balance existing in both primary osteoporosis and physiological osteopenia is a decrease in bone formation, caused by a reduction in the life span of the osteoblastic population at the basic multicellular unit (BMU) level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409438
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  • 8
    Electronic Resource
    Electronic Resource
    Mean wall thickness of trabecular bone packets in the human iliac crest: Changes with age (1978)
    Springer
    Calcified tissue international 26 (1978), S. 13-17 
    Details
    ISSN: 1432-0827
    Keywords: Bone remodelling ; Bone histomorphometry ; Amount of bone ; Osteoporosis ; Osteopenia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mean wall thickness (MWT) of packets of trabecular bone was measured in undecalcified iliac crest bone samples of 36 normal subjects (14 female and 22 male) under polarized light. The mean wall thickness was 49.7±8.7 μm at a mean age of 50.9 years. There existed a significant decrease of MWT with advancing age. With an appositional rate of 0.72 μm/day, the mean formation time of iliac trabecular bone packets is 69 days. The decrease of MWT with age corresponds to a decrease in bone formation at the basic multicellular unit (BMU) level with aging and can partly explain the physiological senile osteopenia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013227
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  • 9
    Electronic Resource
    Electronic Resource
    Evidence for a direct effect of growth hormone on osteoblasts (1993)
    Springer
    Cell & tissue research 273 (1993), S. 279-286 
    Details
    ISSN: 1432-0878
    Keywords: Osteoblasts ; Growth hormone ; Growth hormone-receptor ; Alkaline phosphatase ; Immunocytology ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In order to determine whether growth hormone (GH) exerts a direct effect on osteoblasts, in vitro and in vivo immunocytological studies were carried out on newborn rat calvaria and a clonal osteoblast-like cell line (MC3T3-E1) isolated from newborn mouse calvaria. After exposure to human growth hormone (hGH) or 1,25 dihydroxyvitamin D3 (1,25(OH)2D3), a significant increase in alkaline phosphatase activity was observed in MC3T3-E1 cells. Simultaneous exposure of MC3T3-E1 cells to hGH and 10 nM 1,25(OH)2D3 showed a synergistic effect of the two hormones on this activity. The optimal dose of hGH was 0.1 nM. An immunocytological procedure was performed on ultrathin frozen sections from 7-day-old rat calvaria and MC3T3-E1 cells cultured with hGH. GH-like immunoreactivity was observed in both cases. In calvaria, endogenous GH-like immunoreactivity was localized at the same ultrastructural level (plasma membrane, cytoplasmic and nuclear matrices) as exogenous GH-like immunoreactivity in MC3T3-E1 cells. Following the initial step of binding to the plasma membrane, GH may be internalized in the cytoplasmic matrix and nucleus. In situ hybridization revealed the presence of mRNA coding for GH receptor in calvaria cells. The density of these receptors seemed to be lower in osteoblasts than in hepatocytes. In MC3T3-E1 cells, hGH induced a dose-dependent secretion of insulin-like growth factor 1. In conclusion, these results indicate that GH may act directly on osteoblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312829
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  • 10
    Electronic Resource
    Electronic Resource
    Immunocytochemical evidence for endogenous calcitonin and parathyroid hormone in osteoblasts from the calvaria of neonatal mice (1985)
    Springer
    Cell & tissue research 240 (1985), S. 89-93 
    Details
    ISSN: 1432-0878
    Keywords: Calcitonin ; Parathyroid hormone ; Estradiol ; Estradiol receptors ; Osteoblasts ; Immunocytochemistry ; Cryo-ultramicrotomy ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunoreactivities to endogenous calcitonin, endogenous parathyroid hormone, endogenous estradiol and estradiol receptors were studied in osteoblasts from the calvaria of neonatal mice by immunocytochemistry with the use of ultrathin sections obtained by cryo-ultramicrotomy. Tissues were fixed in glutaraldehyde, postfixed in osmium tetroxide and frozen in liquid nitrogen. Estradiol and estradiol receptors could not be detected in osteoblasts, whereas calcitonin- and parathyroid hormone-like immunoreactivities were observed in this cell type. Calcitonin and parathyroid hormone had similar subcellular localizations: immunoreactivities were observed at the plasma-membrane level, in the cytoplasmic matrix, and in the nucleus. These results provide immunocytological evidence for: 1) the internalization of calcitonin and parathyroid hormone in osteoblasts; 2) a direct participation of calcitonin and parathyroid hormone in the regulation of osteoblasts; 3) the absence of estradiol receptors and estradiol in osteoblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217561
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