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  • Articles: DFG German National Licenses  (6)
  • Osteoblasts  (3)
  • Parathyroid hormone  (2)
  • Speed-of-sound  (2)
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  • Articles: DFG German National Licenses  (6)
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Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Bone loss after cardiac transplantation: Effects of calcium, calcidiol and monofluorophosphate (1993)
    Springer
    Osteoporosis international 3 (1993), S. 322-329 
    Details
    ISSN: 1433-2965
    Keywords: Calcium ; Cardiac transplantation ; Fluoride ; Glucocorticoid-induced osteoporosis ; Parathyroid hormone ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Of 203 patients who underwent cardiac transplantation and were given long-term treatment with cyclosporine and 0.3 mg/kg per day prednisone, 123 were studied prospectively for at least 6 months and 46 for up to 2 years to evaluate the effects on lumbar bone mineral density (BMD) and calcium metabolism of a combined therapy with calcium, calcidiol and disodium monofluorophosphate (MFP). The population was arbitrarily assigned to one of two groups. Group I consisted of patients who had a lumbar spine BMDZ score above −1.5 SD as compared with an age-and sex-matched population and no vertebral fractures. They received daily 1 g elemental calcium and 25 µg (1000 IU) calcidiol. Group II consisted of patients who received daily the same doses of calcium and calcidiol combined with 200 mg MFP, and was divided into two subgroups: (a) osteopenic subjects who had a lumbar spine BMD Z score below −1.5 SD without vertebral fractures and (b) osteoporotic subjects with vertebral fractures. If serum creatinine was higher than 140 µmol/l the daily dose of MFP was tapered to 100 mg. Fifty-four and 27 patients from group I and 38 and 19 patients from group II were followed respectively for 12 and 24 months. In both groups serum parathyroid hormone levels were significantly reduced from the twelfth month in parallel with a significant increase in serum 25-OHD levels. No decline in lumbar BMD occurred in non-osteopenic and non-osteoporotic patients (group I) who received the calcium and calcidiol supplement. In group II, where MFP was added, a significant and linear increase in lumbar BMD was observed. The average increase reached 12.5% after 12 months and 29.5% after 24 months (p〈0.0001). The magnitude of the response was similar to the response previously reported in patients suffering from vertebral fractures due to postmenopausal osteoporosis and treated with the same daily dose of MFP. Because osteoporosis and fractures are not rare in patients after cardiac transplantation, these pilot results may be useful for further prevention and treatment trials of bone loss in this condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01637318
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    Paper (German National Licenses)
    Fulltext
  • 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
    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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    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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  • 5
    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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    Paper (German National Licenses)
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  • 6
    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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    Paper (German National Licenses)
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