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  • Articles  (58)
  • Osteoporosis  (58)
  • Springer  (58)
  • American Geophysical Union (AGU)
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  • Institute of Physics
  • 1995-1999  (30)
  • 1980-1984  (28)
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  • Physics  (58)
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  • Articles  (58)
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  • Springer  (58)
  • American Geophysical Union (AGU)
  • Annual Reviews
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  • 1
    Electronic Resource
    Electronic Resource
    Immobilization osteoporosis and active vitamin D: Effect of active vitamin D analogs on the development of immobilization osteoporosis in rats (1981)
    Springer
    Calcified tissue international 33 (1981), S. 623-630 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Immobilization ; Rats ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The therapeutic effects of vitamin D analogs, 1,24(R)-dihydroxycholecalciferol [1,24(R)(OH)2D3], 1,24(S)-dihydroxycholecalciferol [1,24(S)(OH)2D3], and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] on immobilization osteoporosis were studied in rats. The right hind limb was immobilized through application of a plaster cast following the section of the sciatic nerve. The left hind limb was intact. Vitamin D analogs were orally administered for 6 weeks at dose levels of 0.02 and 0.10µg/kg/day, respectively. The mean lengths of the immobilized femurs were not significantly different from those of the intact femurs in all the experimental groups. In the immobilized femur of animals treated with 1,24(R)(OH)2D3, 0.10µg/kg, dry and ash weights were heavier and calcium and phosphorus contents greater than those in the nontreated group. Furthermore, the amount of calcified bone mass and the cortical thickness of the femurs of the immobilized limb in 1,24(R)(OH)2D3-treated animals were greater than those in the nontreated animals. Treatment with 1,25(OH)2D3 at 0.10µg/kg caused an increase of the bone mass in both immobilized and intact femurs when compared with those of the control group. It was concluded that the administration of 1,24(R)(OH)2D3 diminished the effect of immobilization in the development of osteoporosis without any side effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409500
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  • 2
    Electronic Resource
    Electronic Resource
    Demineralization and pathological physiology of the skeleton in paraplegic rats (1980)
    Springer
    Calcified tissue international 30 (1980), S. 83-90 
    Details
    ISSN: 1432-0827
    Keywords: Paraplegia ; Bone mineral ; Bone blood flow ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mechanism of bone loss after a spinal cord section with paraplegia is still largely unknown. The purpose of this study was to investigate in paraplegic rats the rate and distribution of bone loss, changes in bone calcium metabolism, and bone blood flow. Female Sprague-Dawley rats aged 100–120 days were rendered paraplegic by sectioning the spinal cord at the 11th dorsal vertebra. By comparison with their sham-operated controls (SO controls), we found a diminished bone calcium content in the tibia and femur (paralyzed region) and in the humerus (supralesional region) of the paraplegic animals. In the femur bone calcium loss was present within a week and at 12 weeks had reached 22%; in the tibia it started at about 2 weeks and at 12 weeks had reached 15%; in the humerus it started at about 5 weeks and reached 7.5%. It was not uniform and was greatest in the metaphyseal-epiphyseal regions on either side of the femorotibial joint. The blood flow in femur and tibia was measured by the technique of arteriolar blockade of 15 µm microspheres. It was continuously higher in the paraplegic animals than in the SO controls, from 1 to 12 weeks. In both groups, paraplegics and controls, the bone blood flow was unequally distributed in the two bones; it was greatest in the same metaphyseal-epiphyseal regions contiguous to the femorotibial joint. The 72 h45Ca clearance by the femur and tibia was lower in the paraplegic animals, indicating that bone deposition had slowed down and perhaps that resorption had occurred. The fact that the site of maximum bone calcium loss and the site where the blood flow was greatest are the same suggests a close relationship between the increased blood flow and demineralization, whether it be causal or not.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408611
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  • 3
    Electronic Resource
    Electronic Resource
    Bone involution decrease in exercising middle-aged women (1984)
    Springer
    Calcified tissue international 36 (1984), S. S129 
    Details
    ISSN: 1432-0827
    Keywords: Bone mass ; Exercise ; Aging women ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Physical activity is an important stimulus in the prevention of bone involution. Bilateral bone mineral mass and width of the radius, ulna, and humerus were measured by single photon absorptiometry on 200 women between the ages of 35 and 65 over a 3–4 year period. Two groups were formed: 80 in a control group and 120 in a physical activity group exercising 45 min/day, 3 days/week. The control and physical activity groups were similar in age, height, weight, and level of physical fitness at the beginning of the study. The control group lost bone mineral mass at a rate similar to that of the general population. The left radius bone mineral declined 2.44% per year. Similar rates of decline were observed in the other bones measured. The physical activity group increased in fitness by 13% in the first year of the study. The bone mineral mass of the exercise group declined the first year and then increased; thereby the bone mineral data for the exercise group was analyzed in two sets. During the first year of the program, a decline of 3.77% in bone mineral mass of the left radius, a significantly greater loss than that of the control group, was observed. Decline rates were similar in the other bones measured. In the second and third years, bone mineral mass of the left radius increased by 1.39% per year, and the rate of change was significantly different from that of the control group. There were similar increases in the other bones measured. The data from this study support the importance of physical activity in the prevention of bone mineral loss in the aging female.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02406146
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  • 4
    Electronic Resource
    Electronic Resource
    Evidence for negative correlation between quantitative histological studies and microradiography of iliac crest bone and forearm osteodensitometry in elderly women with osteoporosis (1982)
    Springer
    Calcified tissue international 34 (1982), S. 456-458 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Histomorphometry ; Microradiography ; Osteodensitometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Quantitative histomorphometric and microradiographic analysis of iliac crest bone biopsy specimens of 10 unselected and untreated postmenopausal women with osteoporosis was performed and the results were correlated with the values measured by osteodensitometry on the right forearm. No positive correlation between histomorphometry or microradiography and osteodensitometry was observed. Moreover, the data of various histomorphometric parameters and those of the bone mineral content measured by microradiography revealed a significant negative correlation when compared to the values obtained by osteodensitometry. Our results suggest, that evaluation of one skeletal site is not necessarily representative of the entire skeleton in patients with postmenopausal osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411284
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  • 5
    Electronic Resource
    Electronic Resource
    Clinical usefulness of a bone mineral measurement method on the femoral shaft (1982)
    Springer
    Calcified tissue international 34 (1982), S. 21-28 
    Details
    ISSN: 1432-0827
    Keywords: Photon absorptiometry ; Cortical bone density ; Bone index ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An improved version of a previously described photon absorptiometry method for measuring the bone mineral content of the femoral shaft is presented. The study included 267 healthy persons, who served as control subjects, and 31 osteoporotic and 3 osteomalacic female patients. A monoenergetic source of241Am was used and a fully automatic apparatus designed. The examinations were recorded with an independent microcomputer and secondarily processed by the nuclear unit central computer. The guidelines of Cameron and West were used to perform various calculations from the initial absorption curve, and the clinical usefulness of these was tested. On the one hand, cortical bone density (CBD) and bone linear attenuation coefficient (BLAC) were found adequately to differentiate between osteoporotics and controls, but we defined a discriminative function (F) which allowed even better separation between the two groups. On the other hand, bone index (BI) was found to be the best parameter to follow an individual patient during therapy. These results underline the usefulness of these calculations for detecting and monitoring the progress of pathological states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411203
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  • 6
    Electronic Resource
    Electronic Resource
    Scanning electron microscopy of castrate rat bone (1982)
    Springer
    Calcified tissue international 34 (1982), S. 547-552 
    Details
    ISSN: 1432-0827
    Keywords: Rats ; Osteoporosis ; Anorganic ; Femur ; Castrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The study describes the SEM appearances of endosteal and periosteal surfaces of anorganic femoral diaphyses from 16-month-old normal and castrate male rats. Different types of surfaces could be recognized in both groups. Percentage areas occupied by each surface type were analyzed with a Ladd Data Analyzing Digitizer. Endosteal surfaces were composed of significantly more (P〈0.05) incompletely mineralized, forming surface and significantly less (P〈0.05) completely mineralized, resting surface in castrates than in controls. Both endosteal and periosteal surfaces from experimental bone demonstrated significantly more (P〈0.05) osteoblast lucunae than did control surfaces, and vascular canal entrances were significantly wider (P〈0.001) on castrate endosteal surfaces than on control endosteal surfaces. There was a greater proportion of small nodule forming surface/large nodule forming surface in castrate endosteal bone than in control, and a greater proportion prolonged resting surface/fibrous resting surface in control periosteal bone than in castrate. The results indicate that, when viewed in the SEM, anorganic endosteal and periosteal bone surfaces from femoral diaphyses of old castrate male rats demonstrate appearances characteristic of changes in bone turnover that occur with osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411302
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  • 7
    Electronic Resource
    Electronic Resource
    Whole body and regional retention of99mTc-labeled pyrophosphate at 24 hours: Physiological basis of the method for assessing the metabolism of bone in disease (1983)
    Springer
    Calcified tissue international 35 (1983), S. 37-42 
    Details
    ISSN: 1432-0827
    Keywords: 99mTc-pyrophosphate ; Bone metabolism ; Osteoporosis ; Osteomalacia ; Hyperparathyroidism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The retention of99mTc-labeled pyrophosphate (PPi) at 24 h was measured in 235 patients, 119 of whom had a normal bone metabolism. The mean retention in the group of normal subjects is 52% of the injected dose. Reproducibility of the measurement in a given person is 5.5% coefficient of variation (CV). The value depends strongly on sex (higher in males) and age (higher with increasing age, especially in cortical bone). Retention increases slowly with the decrease in glomerular filtration rate (GFR) between 50 and 120 ml/min; it rises very rapidly with values below 50 ml/min. The slowing down of the GFR with age does not account for the increase in PPi retention with age. When expressed as a percentage of the expected value for sex and age, retention is frequently low in osteoporosis (P〈.001), more so when urinary hydroxyproline is low; it is normal or high in osteomalacia, and in some cases rises after vitamin D treatment is started; it is high in hyperparathyroidism (P〈.01). The PPi retention is correlated with bone calcium accretion rate, alkaline phosphatase level, and above all, the urinary hydroxyproline level. The lower the bone mineralization (Ca/hydroxyproline ratio in biopsy), the higher the retention value. We conclude that the PPi retention is an index of bone metabolism when GFR is higher than 50 ml/min. It allows for classification of metabolic bone diseases according to the bone turnover rate. It has the advantage over the usual biologic examinations in that it affords better observation of highly localized bone disorders and can be used in combination with a morphologic record, the bone scintigraphy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405004
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  • 8
    Electronic Resource
    Electronic Resource
    Errors in measuring trabecular bone by computed tomography due to marrow and bone composition (1983)
    Springer
    Calcified tissue international 35 (1983), S. 148-152 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Computed tomography ; Densitometry ; Osteoporosis ; Osteomalacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The linear attenuation coefficient (μ in cm1) of trabecular bone was modeled for different conditions of bone and marrow composition in order to assess their influence on computed tomography (CT) quantitation. A large relative change (10% of TBV at 15% TBV) of bone concentration resulted in small changes of μ: 2.3% at 60 keV, 3.4% at 44 keV, 5.2% at 29 keV. Relative changes of trabecular bone volume (TBV) on the order of 3% could be detectedin vivo by CT were it not for errors of relocation and for compositional influences on accuracy. The μ (and density) depended critically not only on amounts of bone substance and marrow but on their compositions. Normal variation in the composition of bone substance produced an uncertainty in μ equivalent to 0.5 to 1% TBV. Increases of yellow marrow produced a decrease of μ which could be mistaken for a decrease of bone concentration. The biological variation (90% confidence limit) of marrow composition gives an uncertainty at 15% TBV of about 2.4% TBV at 60 keV, 1.7% at 44 keV, and 1.3% at 29 keV. These correspond to relative uncertainities of 16, 11, and 9% respectively. These factors help explain the large accuracy errors (30%) observed in all studies of trabecular bone where single-energy CT was used. Marrow composition also can affect precision of bone measurement. Systematic shifts of red and yellow marrow could mask biological changes such as those occurring with aging or treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405022
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  • 9
    Electronic Resource
    Electronic Resource
    Osteopenia in juvenile diabetes (1981)
    Springer
    Calcified tissue international 33 (1981), S. 455-457 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Osteoporosis ; Diabetes mellitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The bone mineral status of fifty-one children with diabetes mellitus was studied by single photon absorptiometry. The mean bone mineral content was 13% below values predicted by age, sex, height, and weight. Those children whose diabetes was one year or less in duration were as osteopenic as those whose diabetes was of longer duration. The demineralized children received a higher daily insulin dose than the others. No association was noted between the degree of skeletal demineralization and sex, statural growth, renal function, and serum calcium and phosphorus. No significant changes in bone mineral content were noted longitudinally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409473
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  • 10
    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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  • 11
    Electronic Resource
    Electronic Resource
    Bone metabolism in idiopathic juvenile osteoporosis: A case report (1983)
    Springer
    Calcified tissue international 35 (1983), S. 5-8 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Quantitative bone histology ; Bone metabolism ; Developmental bone disease ; Growth disorder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A previously healthy 12-year-old boy developed pain on walking and x-rays showed osteoporosis. Over the next 2 years deterioration occurred, the condition became extremely severe, and he was confined to a wheelchair. After 5 years, marked kyphoscoliosis and pigeon chest deformity were present and little increase in height occurred. A wheelchair accident at the age of 17 resulted in several major long bone fractures. Iliac crest biopsies were taken at ages 15 and 17, and subjected to quantitative histology. A histochemical technique for osteoclast recognition by acid phosphatase activity showed resorption parameters to be normal. Double tetracycline labeling and histochemical identification of osteoblasts showed no abnormality of endosteal bone formation. Because of “coupling” of endosteal formation and resorption, these measurements might primarily reflect bone turnover. Failure of periosteal bone formation as shown by failure of radial growth of long bones and of epiphyseal growth was clearly evident. It is likely that osteoporosis developed in this patient due to a reduction in bone formation of unknown etiology rather than by increased bone resorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02404998
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  • 12
    Electronic Resource
    Electronic Resource
    Fluoride absorption: The influence of gastric acidity (1984)
    Springer
    Calcified tissue international 36 (1984), S. 302-307 
    Details
    ISSN: 1432-0827
    Keywords: Metabolism ; pH ; Fluorosis ; Osteoporosis ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The influence of gastric acidity on the absorption of intragastrically administered fluoride was investigated in rats. Intact animals were pretreated with atropine or cimetidine to reduce gastric acid secretion or were given fluoride in NaHCO3 to reduce the acidity of the gastric contents. Compared with pentagastrin-treated animals or animals that received fluoride in 0.1 N HCl, their rate of fluoride absorption was markedly reduced as judged by lower plasma fluoride concentrations and areas under the time-plasma concentration curves, especially during the first hour after dosing. In crossover studies with the stomachs isolatedin situ, fluoride absorption was at least 50% faster from a pH 2.1 buffer compared with its absorption from a pH 7.1 buffer. The findings are consistent with the hypothesis that fluoride is absorbed from the gastric lumen principally as the undissociated molecule, HF. The results may contribute to a more complete understanding of acute fluoride toxicity, the development of dental fluorosis and, perhaps, the use of fluoride in the treatment of osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405334
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  • 13
    Electronic Resource
    Electronic Resource
    The effect of bendroflumethiazide and hydrochlorothiazide on the rate of dissolution of calcium hydroxyapatite (1984)
    Springer
    Calcified tissue international 36 (1984), S. 431-434 
    Details
    ISSN: 1432-0827
    Keywords: Bendroflumethiazide ; Hydrochlorothiazide ; Calcium hydroxyapatite ; Hydrolysis ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Inhibition of dissolution of calcium hydroxyapatite in the presence of bendroflumethiazide, Centyl®, and of hydrochlorothiazide has been investigated. The former compound has a pronounced larger inhibitory effect than the latter. The trifluormethyl group in bendroflumethiazide has been shown to hydrolyze, with the release of fluoride and hydrogen ions, presumably forming a carboxylic acid. The inhibitory effect of hydrolyzed bendroflumethiazide is found to be similar to the effect of a potassium fluoride solution with the same fluoride ion concentration, as measured by a fluoride selective ion electrode.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405355
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  • 14
    Electronic Resource
    Electronic Resource
    Total body and regional bone mineral by dual-photon absorptiometry in metabolic bone disease (1984)
    Springer
    Calcified tissue international 36 (1984), S. 8-13 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Renal osteodystrophy ; Fractures ; Bones and bone disease ; Absorptiometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Dual-photon absorptiometry (153Gd) was used to measure bone mineral of the total body and major anatomical areas. Patients with osteoporosis (♂=11, ♀=18) and with renal osteodystrophy (n=17) were significantly below (20%) normal females (n=72) and males (n=13) at most sites. In the osteoporotic patients, but not the renal patients, there was preferential osteopenia of the spine. Bone loss in all anatomical areas became evident after the menopause with an annual loss rate of about 0.7%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405287
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  • 15
    Electronic Resource
    Electronic Resource
    Skeletal demineralization in Turner's syndrome (1982)
    Springer
    Calcified tissue international 34 (1982), S. 519-522 
    Details
    ISSN: 1432-0827
    Keywords: Turner's syndrome ; Ovarian dysgenesis ; Osteoporosis ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The bone mineral status of 17 girls with Turner's syndrome was evaluated by single photon absorptiometry. Bone mineral content (BMC) was 25.4% below that predicted by normalization for age, sex, height, weight, and bone width. Only 25% of this demineralization could be attributed to delayed skeletal maturation. Bones of girls who received estrogen replacement therapy were less demineralized than those of the others. The bone mineral deficit became less pronounced with advancing age. It could not be determined if the apparent effect of estrogens was related to age or if the apparent improvement with age was really due to an effect of estrogen treatment. For 8 subjects followed longitudinally there was no significant change in the BMC deficit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411296
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  • 16
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    Dual-energy X-ray absorptiometry of the calcaneus: Comparison with vertebral dual-energy X-ray absorptiometry and quantitative computed tomography (1995)
    Springer
    Calcified tissue international 56 (1995), S. 14-18 
    Details
    ISSN: 1432-0827
    Keywords: Calcaneus ; Bone mineral content ; DXA ; QCT ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The purpose of this study was to determine the efficacy of using bone mineral measurements of the calcaneus to evaluate osteoporosis. Dual energy X-ray absorptiometry (DXA) of the calcaneus was compared with posteroanterior lumbar absorptiometry (DXA) and vertebral quantitative computed tomography (QCT) measurements in 171 white women (78 normal and 93 osteoporotic). DXA measurement of os calcis mineralization decreased significantly in osteoporosis, but to a lesser extent than in vertebral sites. In normal subjects, good correlations were observed between calcaneal and lumbar DXA (0.69) and QCT (0.56). In subjects with vertebral fractures, there was also good correlation between calcaneal DXA and QCT (0.59–0.69). This suggests that trabecular bone in calcaneus and vertebrae have related involution in cases of vertebral osteoporosis. However, the extent of bone loss is less marked in the calcaneus than in the vertebrae and is not sufficient to be accurately measured over time. We conclude, therefore, that although the global densitometric measurement at this site is not sufficiently sensitive for general use, it can be useful as a epidemiological research tool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298738
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  • 17
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    Ultrasound and densitometry of the calcaneus correlate with the failure loads of cadaveric femurs (1995)
    Springer
    Calcified tissue international 56 (1995), S. 99-103 
    Details
    ISSN: 1432-0827
    Keywords: Calcaneal ultrasound ; Bone mineral density ; Femoral strength ; Hip fracture ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We assessed the bone mineral density (BMD) of 16 matched sets of cadaveric proximal femurs and feet using dual-energy x-ray absorptiometry (DXA). We also estimated the femoral neck length from the DXA scans. Quantitative ultrasound densitometry was used to measure the velocity of sound and broadband ultrasound attenuation (BUA) in the calcaneus of each foot. The proximal femurs were then tested to failure in a loading configuration designed to simulate a fall with impact to the greater trochanter. Femoral neck BMD and trochanteric BMD were strongly associated with the femoral failure load (r2=0.79 and 0.81, respectively; P〈0.001), whereas femoral neck length was modestly correlated with femoral failure load (r2=0.27, P=0.04). Calcaneal BMD (r2=0.63, P〈0.001) and BUA (r2=0.51, P=0.002) were also significantly associated with femoral failure load. Given the small sample size, we were unable to detect differences in the strength of the correlations between the independent parameters and femoral failure load. Using linear multiple regression analyses, the strongest predictor of femoral failure load was a combination of femoral neck BMD and femoral neck length (R2=0.85, P〈0.001). Thus, it appears that both femoral and calcaneal bone mineral properties may be useful for identifying those persons at greatest risk for hip fracture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296338
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  • 18
    Electronic Resource
    Electronic Resource
    A comparative bioavailability study on two new sustained-release formulations of disodiummonofluorophosphate versus a nonsustained-release formulation in healthy volunteers (1995)
    Springer
    Calcified tissue international 56 (1995), S. 196-200 
    Details
    ISSN: 1432-0827
    Keywords: Disodiummonofluorophosphate ; Osteoporosis ; Fluoride peak serum concentration ; Bioavailability ; Sustained-release formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract In 12 healthy volunteers the pharmacokinetic parameters of two new sustained-release formulations of disodiummonofluorophosphate (MFP) (B and C) were compared with those of a nonsustained-release reference preparation (A). This randomized study had a single-dose, triple-cross over design and consisted of 3 trial days separated by a 1-week washout period. Serial blood samples were obtained over a period of 24 hours and 24-hour urine was collected. Serum and urine fluoride concentrations were determined using an ion-sensitive electrode (Orion Research). The results of this study showed a significant reduction of the area under the serum concentration versus time curve (AUC) for the sustained-release formulations (AUC B: 1487±354 ng/mlxhour, AUC C: 1369±384 ng/mlxhour) compared with the reference preparation (AUC A: 2374±652 ng/mlxhour) (B/A: 63%, C/A: 58%) (P〈0.001). Furthermore, the peak serum concentrations of fluoride (Cmax) for B and C (CmaxB: 166±42 ng/ml, CmaxC: 110±48 ng/ml) were significantly lower than for A (CmaxA: 380±77 ng/ml) (P〈0.001). The 24-hour urine fluoride recovery rates were 5.6±0.7 mg fluoride for A, 3.6±0.8 mg for B, and 3.2±1.1 mg for C and corresponded well to the relative fluoride bioavailability, as concluded from the serum fluoride concentration. In conclusion, the sustained-release preparations of MFP led to a decrease of fluoride bioavailability and avoided high peak serum concentrations.
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    URL: http://dx.doi.org/10.1007/BF00298609
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    Alterations of bone mineral density of the femurs in hemiplegia (1995)
    Springer
    Calcified tissue international 56 (1995), S. 259-262 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Bone mineral density ; Hemiplegia ; Activity of daily living
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We evaluated the bone mineral density (BMD) of the bilateral femurs in 112 patients with hemiplegia using dual-energy X-ray absorptiometry in order to elucidate the effect of disuse and immobilization. BMD of the paretic side was significantly reduced compared with that of the nonparetic side in hemiplegic patients (femoral neck 0.582±0.014 g/cm2 versus 0.623±0.014 g/cm2 and total femur 0.645±0.02 g/cm2 versus 0.702±0.017 g/cm2; mean±SEM, P〈0.01, respectively). Femoral BMD in both the paretic and nonparetic limb had significantly (P〈0.01) lower values than in age- and sex-matched controls, but the paretic side had a more significant reduction of BMD; femoral neck-20% versus -14% and total femur -24% versus -18%. In addition, patients with impaired activities of daily living (ADL), evaluated by a mobility score, had significantly decreased BMD ratios of paretic/nonparetic side than patients with improved ADL (femoral neck 91% versus 97%, P〈0.01 and total femur 89% versus 94%, P〈0.05). Our results indicated that BMD of both femurs of patients with hemiplegia was reduced, although the paretic side showed a greater BMD decrease. This decrease might be prevented or reduced by improvement of ADL.
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    URL: http://dx.doi.org/10.1007/BF00318043
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    Bone density in medieval skeletons (1995)
    Springer
    Calcified tissue international 56 (1995), S. 355-358 
    Details
    ISSN: 1432-0827
    Keywords: Anthropometry ; Archeology ; Bone density ; Densitometry ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We studied the most complete skeletons found in an excavation from the 14th and 15th century in central Stockholm. One hundred eighty-seven were from men and 156 from women: 241 individuals were estimated to be between 20 and 39 and 102 between 40 and 59 years old at death. We examined the bones radiographically and by dual photon absorptiometry. The bone mineral density (BMD) was similar to the finding in North America and Northern Europe today as was the relationship between men and women. However, there appeared to be a higher diaphyseal bone density in the lower extremities, especially in men. The femur score was higher and the BMD of the femoral and tibial shafts was higher than today. In the upper extremities the diaphyseal bone density was lower. Meema's index, as well as the metacarpal score, was smaller than in individuals in this century and the BMD of the humeral shaft was also lower than seen today. Overall, the metaphyseal bone density was similar to what we now consider normal; i.e., the mean BMD of the femoral neck was 0.96 g/cm2 in men and 0.90 g/cm2 in women and of the distal radius 0.43 and 0.32 g/cm2, respectively. The low diaphyseal density and in the upper extremities may be related to the nutritional status, whereas the greater need for walking and standing in the 14th and 15th century might have led to the high diaphyseal density in the lower extremities. There was no evidence of bone loss after 40 years of age in either sex in our study. The average expected lifespan for an adult individual was less than 50 years and we suggest that the relatively high bone density in the older age group may be due to selection of the most physically fit. The activity pattern, therefore, may be considered the most important determinant for the differences.
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    URL: http://dx.doi.org/10.1007/BF00301601
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    Differential effects of glucocorticoids on human osteoblastic cell metabolism in vitro (1995)
    Springer
    Calcified tissue international 57 (1995), S. 120-126 
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    ISSN: 1432-0827
    Keywords: Glucocorticoids ; Osteoblasts ; Bone ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Clinical observations suggest that the onset and severity of glucocorticoid (GC) induced osteoporosis is dependent on the duration of the GC treatment and the applied GC compound. To test whether these in vivo observations are reflected by different in vitro effects of various synthetic GCs on human bone cell metabolism we isolated human osteoblast-like cells (HOC) from bone biopsies of healthy (no clinical symptoms of arthritis or arthrosis) adults who underwent selective orthopedic surgery. HOC were identified as bone cells by 1,25-vitamin D3-stimulated increase of specific alkaline phosphatase (ALP) activity, secretion of osteocalcin and type-I procollagen peptide, and the ability to form mineral in vitro. We investigated the effects of dexamethasone (dexa), methylprednisolone (mpred), prednisolone (pred), and deflazacort (defla) on DNA-synthesis, ALP, and osteocalcin (OC)- and type-I procollagen peptide secretion of HOC in vitro. In summary, (1) GC exposure stimulates DNA synthesis after 6–12-hour treatment periods; (2) dex and mpred strongly inhibit DNA (48-hour treatment) and collagen synthesis but stimulate ALP, whereas pred and defla exhibit smaller effects on DNA synthesis, ALP, and collagen production; and (3) all tested glucocorticoids inhibit OC secretion by HOC in vitro. Thus, the effect of GC on DNA synthesis of HOC varies with the duration of GC exposure, and dex and mpred more potently affect HOC metabolism in vitro than pred and defla.
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    URL: http://dx.doi.org/10.1007/BF00298432
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    Influence of degenerative joint disease on spinal bone mineral measurements in postmenopausal women (1995)
    Springer
    Calcified tissue international 57 (1995), S. 169-174 
    Details
    ISSN: 1432-0827
    Keywords: Quantitative computed tomography ; Dual X-ray absorptiometry ; Degenerative joint disease ; Osteoporosis ; Bone mineral density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We assessed the impact of various forms of spinal degenerative joint disease (DJD) on bone mineral density (BMD) measured by quantitative computed tomography (QCT) and dual X-ray absorptiometry (DXA) in a group of postmenopausal women. Lateral (T4-L4) and AP (L1-L4) spinal radiographs were reviewed for fracture and DJD in 209 women (mean age 62.6±6.7). The severity of DJD findings was graded as 0,1, or 2 on the lumbar films, except for vertebral osteophytes which were graded from 0 to 3. Vertebral fractures were defined semiquantitatively as approximately 20% reduction in anterior, middle, or posterior vertebral height. BMD was measured in all subjects by QCT and DXA, including posteroanterior DXA (PA-DXA), lateral DXA (L-DXA) and midlateral DXA (mL-DXA). When BMD was measured by QCT and mL-DXA in the 168 women without fractures, no significant differences were found between women with and those without DJD. However, BMD by PA-DXA was significantly higher in women with DJD changes, particularly when osteophytes were present at the vertebral bodies or facet joints. BMD by L-DXA was less affecied by DJD. For this measurement a significant increase in BMD was only noted in subjects with vertebral osteophytes. Multivariate analysis of variance (MANOVA) showed that BMD by QCT and mL-DXA was not affected by DJD. In contrast, for all women, BMD by PA-and L-DXA was affected more by DJD than by fracture status. Chi-square testing demonstrated no significant relationships between vertebral fractures and any of the DJD changes. We conclude that QCT and mL-DXA are superior to PA-DXA and L-DXA in detecting bone loss in patients with DJD. Thus, for these patients, BMD assessment by QCT or mL-DXA may be advisable.
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    URL: http://dx.doi.org/10.1007/BF00310253
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    Ineffectiveness of calcitonin on a local-disuse osteoporosis in the sheep: A histomorphometric study (1995)
    Springer
    Calcified tissue international 57 (1995), S. 224-228 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Disuse ; Calcitonin ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Local immobilization is a good model for studying disuse-induced bone loss and to appreciate the effects of drugs, especially preventive action of antiresorptive therapy. In fact, increased osteoclastic activity is the main point of such a bone loss. The effect of salmon calcitonin was investigated on immobilization-induced osteoporosis in the sheep. Twenty-four nonovariectomized, adult, female, Welsh mountain sheep were submitted, by an external fixator procedure, to hock joint immobilization from the tibia to the the metatarsus for 12 weeks. The sheep were randomized into two groups receiving either an injection of placebo or salmon calcitonin (100 IU) three times per week, for 12 weeks. Histomorphometric analysis was performed on pre-and posttherapeutic transiliac bone biopsies, and on immobilized (left) and nonimmobilized calcanei removed after sacrifice. Results showed a 29% significant decrease of cancellous bone volume in the placebo group due to a significant reduced trabecular thickness when we compared immobilized versus nonimmobilized calcaneus. This structural adaptation appeared to be the consequence of an overall increased bone turnover. In the calcitonin group, same changes were observed, with a 23% reduction of bone mass in the immobilized calcaneus. By comparing calcitonin with placebo groups in both left and right calcanei, no difference was found. On the other hand, a significant increase of mineralization parameters in the iliac crest was only observed in the calcitonin group. In conclusion, salmon calcitonin, at a dose of 100 IU/day three times a week, was ineffective in preventing local disuse osteoporosis in this sheep model.
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    URL: http://dx.doi.org/10.1007/BF00310263
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    Ultrasound, densitometry, and extraskeletal appendicular fracture risk factors: A cross-sectional report on The Saunders County Bone Quality Study (1995)
    Springer
    Calcified tissue international 57 (1995), S. 267-271 
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    ISSN: 1432-0827
    Keywords: Densitometry ; Fracture ; Osteoporosis ; Risk factors ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The Saunders County Bone Quality Study was designed to determine the feasibility of ultrasonic bone measurement, at the patella, as a predictor of low-trauma fractures in a runal population-based study. At the first visit of this 4-year longitudinal study, anthropometric and clinical measurements and medical, surgical, and fracture histories were obtained for the 1428 participants (899 women and 529 men). Explored risk factors for low-trauma fractures included age, sex, calcium intake, alcohol and caffeine ingestion, tobacco use, body mass and grip strength, age of menopause, estrogen replacement therapy, propensity to fall, distal radius and ulna bone mineral content, and bone density. Forward multivariate logistic regression analysis showed that lower ultrasound values are more consistently associated with reported low-trauma appendicular fractures than the commonly reported forearm absorptiometry measures of radius mineral content and density. When ultrasound, age, and the extra skeletal risk factors were included in an additional multivariate model, only age and ultrasound were significantly associated with appendicular fracture history in women (P=0.0003), whereas only ultrasound was associated in the men (P=0.001). We conclude that ultrasound is a better measure of association with reported low-trauma fractures than the commonly reported forearm SPA measures. Even after adjustment for many of the extra skeletal risk factors, low AVU is highly associated with low-trauma fracture status for both women and men.
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    URL: http://dx.doi.org/10.1007/BF00298881
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    Progesterone receptors are expressed in human osteoblast-like cell lines and in primary human osteoblast cultures (1995)
    Springer
    Calcified tissue international 57 (1995), S. 436-441 
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    ISSN: 1432-0827
    Keywords: Human osteoblast ; Progesterone receptor ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Expression of progesterone receptors (PR) was studied in human osteoblast-like cell lines and primary human osteoblast cultures at the molecular level. Using the sensitive reverse transcriptase polymerase chain reaction (RT-PCR) and oligonucleotide primers which flank the progesterone-binding domain of human PR, progesterone receptor (PR) mRNA was detected in three osteoblast-like cell lines-HOS-TE85, MG-63, and SAOS-2. When compared with β-actin gene expression, levels of PRmRNA transcripts varied between cell lines (PRmRNA in HOS-TE85〉MG-63 ≫ SAOS-2). In addition, RT-PCR confirmed the presence of PRmRNA transcripts in primary human osteoblast cells cultured from collagenase-treated bone. Immunostaining was used to visualize PR protein in cells. All osteoblast-like cell lines showed specific staining for PR. Immunoreactivity was distributed equally in the nucleus and cytoplasm. The level of staining was significantly lower than that detected in PR-positive MCF-7 breast cancer cells though well above background levels obtained for PR-negative HeLa cells. The finding that PR is expressed at both the level of mRNA and protein in several osteoblast-like cell lines as well as in human primary osteoblast cultures indicates that bone-forming osteoblast cells are direct targets for progesterone action.
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    URL: http://dx.doi.org/10.1007/BF00301947
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    Mechanically induced periosteal bone formation is paralleled by the upregulation of collagen type one mRNA in osteocytes as measured by In situ reverse transcript-polymerase chain reaction (1995)
    Springer
    Calcified tissue international 57 (1995), S. 456-462 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Remodeling ; Osteoporosis ; Collagen ; Strain ; Mechanical ; Reverse transcript polymerase chain reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Reverse transcript polymerase chain reaction (RT-PCR) was developed for use in situ to measure mechanically mediated changes in gene expression activity in osteocytes within dense cortical bone. Using the functionally isolated turkey ulna model of bone adaptation, the left ulna of 6 old adult (36–40 months) male turkeys were subject to 4 weeks of a mechanical regimen consisting either of (1) 3000 microstrain at 1 Hz for 5 minutes/day or (2) 500 microstrain at 30 Hz for 10 minutes/day. The right ulma of each bird remained intact and served as control. Only a small percentage of osteocytes in the intact control bones and the 3000 microstrain ulnae showed any evidence of mRNA for collagen (each 1.2%±0.3%). However, mRNA for collagen type I was strongly evident in 92.4% (±2%) of the osteocytes within the ulnae subject to the high frequency, low magnitude load. Sense primer control sections from both experimental and intact animals were used to verify that only osteocytes of the loaded bone had elevated the level of collagen mRNA. This high frequency, low magnitude mechanical stimulus was also sufficient to stimulate substantial new bone formation (14%±5% over intact controls), whereas the low frequency, high magnitude stimulus failed to elicit any bone formation (-3%±7%). These experiments show that specific mechanical regimens can activate the osteocyte's expression of a message responsible for the synthesis of proteins remote from the site where the formation of bone is ultimately to occur, even under systemic distress such as aging. Further, these data suggest that osteocytes perceive the strain environment and that they play a role in orchestrating the modeling/remodeling response. By developing a technique as flexible and powerful as RT-PCR for use in dense cortical bone, determining the relative contribution of specific proteins to the transduction of regulatory signals to formative or resorptive responses is facilitated.
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    URL: http://dx.doi.org/10.1007/BF00301950
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    Total body bone mineral and lean body mass by dual-photon absorptiometry (1981)
    Springer
    Calcified tissue international 33 (1981), S. 365-368 
    Details
    ISSN: 1432-0827
    Keywords: Absorptiometry ; Osteoporosis ; Spinal bone ; Bone mineral content ; Neutron activation ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Dual-photon absorptiometry using153Gd (44 and 100 keV) was used to measure the bone mineral content (BMC) of the trunk and of the total body (TBBM) in 7 volunteers with no overt bone disease. These values were compared to those obtained with partial-body neutron activation of calcium (trunk Ca). The trunk Ca seemed to represent best a 60 × 30 cm area; the correlation coefficient with the corresponding BMC in that area was 0.97 (SEE ⋍ 7%). Trunk Ca was also highly correlated with TBBM (r=0.96; SEE=8%) and with radius BMC (r=0.92; SEE=11%), but the correlations with the BMC of smaller subareas of the trunk were lower (r⋍0.9; SEE ∼ 12%). The BMC of the lumbar spine was only moderately correlated with trunk Ca, radius BMC and TBBM (r ∼ 0.82; SEE ∼ 18%), and only slightly more associated with trunk BMC (r ∼ 0.88; SEE ∼ 14%). The BMC of the combined lumbar-thoracic spine showed higher correlations with trunk Ca, radius BMC and TBBM (r ∼ 0.87; SEE ∼ 13%), and trunk BMC (r=0.93; SEE ∼ 10%). An accurate and sensitive measure of spinal status requires a direct measurement of that area.
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    URL: http://dx.doi.org/10.1007/BF02409457
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    Effects of castration on the bone structure of male rats: A model of osteoporosis (1980)
    Springer
    Calcified tissue international 32 (1980), S. 77-82 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Castration ; Density ; Femur ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Forty young (23-day-old) and thirty old (1-year-old) male rats were castrated and sacrificed with controls at intervals up to 18 months of age. No differences were observed between femurs or mandibles of rats castrated at 23 days and those of controls. Year-old castrate rats developed femoral osteoporosis after 2 months, which became more pronounced 4 months after castration. This was characterized by reductions in femoral density, dry weight, dry weight per unit length, and ash weight, and by the appearance of resorption cavities in diaphyseal walls and a sparsity of trabeculae in metaphyses and epiphyses of castrate femurs. These results indicate that the year-old castrate male rat may be a valuable experimental model for studies of the treatment of osteoporosis.
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    URL: http://dx.doi.org/10.1007/BF02408524
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    Comparison of bone apatite in osteoporotic and normal Eskimos (1983)
    Springer
    Calcified tissue international 35 (1983), S. 392-393 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Infrared ; Bone mineral ; Bone resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An infrared and x-ray diffraction study of osteoporotic and normal, archaeological Eskimo bones. Osteoporotic bone apatite is greater in crystal size and/or perfection and lower in CO3 than normal bone apatite.
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    URL: http://dx.doi.org/10.1007/BF02405064
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    Functional strain as a determinant for bone remodeling (1984)
    Springer
    Calcified tissue international 36 (1984), S. S56 
    Details
    ISSN: 1432-0827
    Keywords: Mechanical strain ; Bone remodeling ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Mechanical function has always been acknowledged to have a significant, continuing but hitherto unquantified influence on bone remodeling. The structural objective of this relationship is presumably to ensure that, at each location throughout the skeleton, there is sufficient bone tissue, appropriately placed, to withstand functional load-bearing without damage. The architectural modifications necessary to achieve and maintain this structural competence are made by the coordinated remodeling activity of populations of osteoblasts and osteoclasts. The specific structure-function objectives at each location remain undefined, as are the mechanisms by which tissue loading is transduced into cellular control. The remodeling responses following a variety of experimental alterations in bones' strain environment are presented. Their significance to the process of remodeling control is discussed, and a scheme for the interaction of mechanical and hormonal influences proposed.
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    URL: http://dx.doi.org/10.1007/BF02406134
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    Role of parathyroid hormone and 1,25-dihydroxyvitamin D3 in the development of osteopenia in oophorectomized rats (1982)
    Springer
    Calcified tissue international 34 (1982), S. 510-514 
    Details
    ISSN: 1432-0827
    Keywords: Rats ; Osteopenia of oophorectomy ; 1,25-Dihydroxyvitamin D3 ; Parathyroid hormone ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effect of ovarian insufficiency on calcium metabolism has been thought to involve an increased bone resorptive effect of parathyroid hormone and possible impaired synthesis of 1,25-dihydroxyvitamin D3. In the present study a rat model allowing for controlled serum levels of parathyroid hormone and 1,25-dihydroxyvitamin D3 was used. Oophorectomy in this species is associated with increased serum levels of 1,25-dihydroxyvitamin D3 and decreased bone mass. Although thyroparathyroidectomy increased bone mass, an increased sensitivity of bone to parathyroid hormone in oophorectomized rats was not observed. Thus the development of the osteopenia did not seem to be related to increased parathyroid hormone sensitivity or to reduced levels of 1,25-dihydroxyvitamin D3. Exogenous 1,25-dihydroxyvitamin D3 increased bone mass in oophorectomized as well as intact rats. Intestinal calcium transport was increased by moderate doses of 1,25-dihydroxyvitamin D3. Intestinal calcium transport was also reduced by thyroparathyroidectomy and increased by the administration of parathyroid extract. A tendency for increased accumulation of 1,25-dihydroxyvitamin D3 in blood in oophorectomized rats has been noted. It is suggested that the tendency to hypercalcemia in ovarian-insufficient females given 1-hydroxylated vitamin D compounds may be related to a diminished metabolism of 1,25-dihydroxyvitamin D3.
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    URL: http://dx.doi.org/10.1007/BF02411294
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    Bone density in white Brazilian women: Rapid loss at the time around the menopause (1995)
    Springer
    Calcified tissue international 56 (1995), S. 186-191 
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    ISSN: 1432-0827
    Keywords: Bone mineral density ; Dual energy X-ray absorptiometry ; Osteoporosis ; Menopause
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Dual energy x-ray absorptiometry (DXA) was used to measure bone mineral density (BMD) of the lumbar spine and proximal femur (neck, Ward's triangle, and trochanter) in 417 normal women (aged 20–79) living in São Paulo, Brazil. Bone density decreased with age at all sites. At the spine, the greatest decrease occurred during the sixth decade, with an average 11.4% bone loss compared with the previous decade. Stratifying the subjects according to menopausal status revealed that the fastest bone occurred at the time around the menopause (ages 45–60) when the rate of bone loss (-0.66%/year) was almost twice as rapid as in postmenopausal women (-0.39%/year). Although significant linear rates of bone loss were detected in all proximal femur sites before the menopause, a menopause-dependent pattern was less evident that at the spine. Lifetime rates of bone loss at the appendicular skeleton were-0.43,-0.62, and-0.35%/year at the femoral neck, Ward's triangle, and trochanteric area, respectively. After the menopause, BMD declined with menopausal age at all sites, although the rate of bone loss was faster at the femoral neck (-0.62%/year) and Ward's triangle (-0.84%/year) than at the spine-0.49%/year). The results are consistent with the notion that in women, the fastest bone loss occurs at the time round the menopause, most likely consequent to ovarian failure; and that faster rates of bone loss are detected at the proximal femur than at the lumbar spine in late postmenopausal women.
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    URL: http://dx.doi.org/10.1007/BF00298607
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    Restoration of severely depleted femoral trabecular bone in ovariectomized rats by parathyroid hormone-(1–34) (1995)
    Springer
    Calcified tissue international 56 (1995), S. 227-231 
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    ISSN: 1432-0827
    Keywords: Parathyroid hormone ; Osteoporosis ; Trabecular bone ; Cortical bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract It is commonly believed that the parathyroid hormone's (PTH's) main function in bone is to stimulate osteoclastic resorption. However, intermittent injections of small doses of PTH holoprotein, but more often its bioactive hPTH-(1–34) fragment, have been shown to stimulate bone growth in animals and humans through their ability to stimulate adenylyl cyclase and not their ability to independently activate a protein kinases-C stimulating mechanism. This anabolic action suggests that PTH might be an effective therapeutic for osteoporosis. If so, the hormone must be able to restore severely depleted trabecular bone, and the goal of this study was to find out if it can. To do this, we started a multiweek program of daily subcutaneous injections of 0.8 nmoles of hPTH-(1–34)/100 g body weight into rats at 4, 8, or 16 weeks after ovariectomy (OVX) and the increasingly severe selective loss of trabecular bone. These injections strongly stimulated femoral trabecular bone to grow and mineralize at the same rate regardless of how much of it had been lost before the injections were started. Thus, the progressively depleting trabecular bone in the femurs of OVX rats does not lose its anabolic responsiveness to PTH. This finding is another indication of the likelihood of small, adenylyl cyclase-stimulating PTH fragments being effective therapeutics for osteoporosis.
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    URL: http://dx.doi.org/10.1007/BF00298615
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    Bone histomorphometry in men with spinal osteoporosis (1995)
    Springer
    Calcified tissue international 56 (1995), S. 359-363 
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    ISSN: 1432-0827
    Keywords: Histomorphometry ; Osteoporosis ; Males
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The purpose of this investigation was to determine whether there is an effect of age and the presence of predisposing risk factors on the pattern of bone resorption in men with spinal osteoporosis. We present iliac bone histomorphometric data after in vivo double tetracycline labeling in 21 men aged 34–74 with significant spinal osteoporosis as evidenced by compression spinal fracture without significant trauma. Fourteen of the 21 men (67%) had identifiable predisposing risk factors for their osteoporosis, such as ethanol abuse, hypercortisolism, hypogonadism, or underlying medical conditions. The other 7 men (33%) had no such identifiable risk factors. The conclusions of the study were that (1) there was no correlation between age of the patient and degree of bone resorption based on two parameters of resorption and (2) there was no difference in the pattern of bone resorption between the groups with and without known predisposing risk factors for osteoporosis or underlying medical conditions.
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    URL: http://dx.doi.org/10.1007/BF00301602
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    Relation of early menarche to high bone mineral density (1995)
    Springer
    Calcified tissue international 57 (1995), S. 11-14 
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    ISSN: 1432-0827
    Keywords: Bone mineral density ; Menopause ; Menarche ; Osteoporosis ; Peak bone mass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The study of background factors in individuals with high bone mineral density (BMD) may provide useful information in the prevention of osteoporosis. We investigated the relationship of reproductive factors to BMD. In 519 female volunteers (327 postmenopausal and 192 premenopausal women) ranging in age from 21 to 74 (mean 52.3 ±11.8) years, spinal BMD values were obtained using both quantitative computed tomography and dual x-ray absorptiometry. The z score was calculated from the mean BMD in each 5-year age group, and high BMD and low BMD was defined as BMD with z score 〉+1.5 and 〈-1.5, respectively. Normal BMD was defined as BMD within the range-1.0 〈z score 〈+1.0. Long reproductive period, early menarche, and late menopause were associated with high BMD. Among these, the reproductive period showed the strongest association with BMD. In postmenopausal women, early menopause had a significant relationship with low BMD, and early menarche also had some relation to high BMD. In premenopausal women, there was a significant relationship between early menarche and high BMD. The age at menarche may have a strong association with peak bone mass, as suggested by the positive correlation of early menarche with high BMD observed in this study. It is considered important to prevent risk factors that disturb the beginning of menstruation in adolescent girls.
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    URL: http://dx.doi.org/10.1007/BF00298989
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    Vertebral fractures and osteopenia in chronic alcoholic patients (1995)
    Springer
    Calcified tissue international 57 (1995), S. 111-114 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Alcoholism ; Ethanol ; Vertebral fractures ; Bone fractures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract To assess whether vertebral fractures are associated with osteopenia in chronic alcoholic patients, a transversal study was carried out in 76 chronic alcoholic males and 62 age-matched healthy males. Lumbar bone mineral density (BMD) by dual photon absorptiometry and spinal chest X-ray films were done in all patients. Twenty-seven patients (36%) had vertebral fractures, but only 5 of them had a BMD below the fracture threshold. Twenty-two patients (29%) had osteoporosis by densitometric criteria. There were no significant differences in lumbar BMD between alcoholic patients with and without vertebral fractures (1.11±0.2 versus 1.13±0.2, P=ns). Previous trauma was recorded in 24 of the 27 patients with vertebral fractures and in 28 of the 49 patients without vertebral fractures (P〈0.001). Moreover, patients with vertebral fractures had more peripheral fractures than patients without vertebral fractures (81% versus 49%, P=0.01). Only one patient was aware of a previous episode of traumatic vertebral fracture. In conclusion, chronic alcoholics frequently have traumas and vertebral fractures, the latter despite having a lumbar BMD above the fracture threshold, suggesting a frequent but unrecognized association between both processes. These results suggest that both spine films and BMD measurements should be obtained for diagnosis of osteoporosis in alcoholic patients.
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    URL: http://dx.doi.org/10.1007/BF00298430
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    Site-specific bone mass differences of the lower extremities in 17-year-old ice hockey players (1996)
    Springer
    Calcified tissue international 59 (1996), S. 443-448 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Bone mass ; Adolescents ; Ice hockey ; Physical activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The purpose of the present study was to evaluate bone mass in the pelvis and lower extremities in young ice hockey players, and especially to investigate whether any differences are related to the type and magnitude of weightbearing loading and muscle stress. The ice hockey group consisted of 22 boys (mean age 16.9±0.3) from three different ice hockey teams training for about 9 hours/week (mean 9.3±2.0, range 6–15). The reference group consisted of 22 boys (age 16.8±0.3) not training for more than 4 hours per week (mean 1.5±1.5, range 0–4). The groups were matched according to age, pubertal stage, weight, and height. Areal bone mineral density (BMD) was measured in total body, head, pelvis, ala ossis ilii, femoral neck, trochanter, femur diaphysis, and tibia diaphysis using dual energy X-ray absorptiometry. Isokinetic muscle strength of the quadriceps and hamstrings muscles was measured using an isokinetic dynamometer. BMDs of the total body, femoral neck, trochanter, and pelvis, but not of the head, ala ossis ilii, femur diaphysis, and tibia diaphysis, were found to be significantly higher (P〈0.05) in the ice hockey group. Muscle strength of the quadriceps muscles was also found to be significantly higher among the ice hockey players, but this greater muscle strength did not predict any BMD site significantly. However, in the reference group, there was a general strong relationship between muscle strength and BMD. This study has demonstrated significantly higher BMD in adlescent ice hockey players than in referents on a low or moderate level of physical activity. The differences seem to be site-specific and may be related to the type and magnitude of loading acting on each site, during off-season training and preferentially during ice hockey. The nonsignificant differences in BMD of the tibia and femur diaphyses may reflect that the compressive forces acting on these sites during ice hockey are not of sufficient magnitude to influence BMD. High muscle stress in itself, without weight-bearing loading, acting on the ala ossis ilii in adolescent boys does not seem to increase BMD, and an increased muscle strength does not predict BMD in highly trained adolescent boys.
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    URL: http://dx.doi.org/10.1007/BF00369208
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    Mean wall thickness and formation periods of trabecular bone packets in idiopathic osteoporosis (1981)
    Springer
    Calcified tissue international 33 (1981), S. 199-204 
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    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.
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    URL: http://dx.doi.org/10.1007/BF02409438
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    Factors in response to treatment of early postmenopausal bone loss (1981)
    Springer
    Calcified tissue international 33 (1981), S. 575-581 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Vitamin D ; Bone mineral ; Estrogen ; Aging ; Thiazide ; Fluoride ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Bone mineral content (BMC) was measured by125I photon absorptiometry every 3 months in 264 normal females (45–54 years) over a 2-year period together with serum samples for calcium, phosphate, magnesium, creatinine, alkaline phosphatases, potassium, and protein. A 48-h urinary calcium and creatinine measurement was obtained. The subjects were divided into 7 treatment groups and 3 placebo groups. Five of the treatments (thiazide, vitamin D3, fluoride + vitamin D3, fluoride, and 1αD3) were ineffective at the doses used; the annual loss of compact bone was 1.5–2.2% (-X=1.8%), similar to the loss seen with placebos. Estrogen and estrogen + thiazide, in contrast, produced a 1.34% annual increase of BMC. The subjects were divided into groups with low, medium, and high initial BMC. Also, individual regressions for bone change were calculated and the subjects were divided into groups of responders, maintainers, and losers (annual change of 〉0%, 0 to −1%, and 〉−1%, respectively). The initial BMC status did not consistently affect bone or biochemical responses to the therapeutic agents. Estrogen was effective even in subjects with high BMC, whereas the other agents did not inhibit bone loss even in subjects with low initial BMC. Virtually all subjects responded to estrogen positively; in contrast we could not identify a subset of “responders” with any of the other treatments. Time since menopause appeared to influence the bone changes, although it was not a significant effect given the sample size. Bone loss in groups not treated with estrogens was 2%/year at 20 months after menopause with a decline to 1.3%/year at 45 months post-menopause. There was no apparent decline in the bone response to estrogen during the first 4 years after menopause, and in fact bone response tended to increase with time.
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    URL: http://dx.doi.org/10.1007/BF02409494
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    Mast-cell proliferation in postmenopausal osteoporosis (1983)
    Springer
    Calcified tissue international 35 (1983), S. 29-31 
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    ISSN: 1432-0827
    Keywords: Mast cells ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Because mast cell proliferation has been reported in disorders of abnormal bone remodeling, we quantitated the number of mast cells in undecalcified section of iliac crest bone from 16 untreated women with postmenopausal osteoporosis and contrasted the findings to values from 10 normal women and 12 normal men. The mean number of marrow mast cells was greater in normal women than men (1.17 vs 0.40 cells per mm2,P〈0.05). Compared to the normal women, osteoporotic women had a greater number of mast cells in the marrow (3.38 vs 1.17 cells per mm2,P〈0.01). However, there was no statistically significant correlation between the number of marrow mast cells and either the patient's age or the severity of the bone lesions, as assessed by histomorphometry. Our findings confirm the association between increased numbers of mast cells and postmenopausal osteoporosis.
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    URL: http://dx.doi.org/10.1007/BF02405002
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    Preliminary observations of a form of coherence therapy for osteoporosis (1984)
    Springer
    Calcified tissue international 36 (1984), S. 341-343 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Coherence Therapy ; Histomorphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Five patients suffering from osteoporosis were subjected to from three to eight cycles of a form of Coherence Therapy for Osteoporosis (1) used at this center. Assessment of the patients' trabecular bone remodeling activity as measured by histomorphometric analyses of trans-iliac crest bone biopsies showed a marked improvement.
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    URL: http://dx.doi.org/10.1007/BF02405341
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    Racial differences in calcitonin and katacalcin (1984)
    Springer
    Calcified tissue international 36 (1984), S. 725-728 
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    ISSN: 1432-0827
    Keywords: Race ; Osteoporosis ; Calcitonin ; Katacalcin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Profound racial differences exist in the incidence of osteoporosis, particularly in women. To investigate possible underlying reasons for this, we have measured the circulating levels of calcitonin (iCT), a bone-protecting hormone, and its flanking peptide, katacalcin (iKC), in black Gambian and white British populations. Whilst sex differences in both peptides were observed, with males having higher levels than females, the most striking finding was that white women have the lowest iCT levels. This important observation may explain, at least in part, why osteoporosis is particularly a disease of white, postmenopausal women.
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    URL: http://dx.doi.org/10.1007/BF02405396
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    Effects of 1,25(OH)2D3 on bone tissue in the rabbit: Studies on fracture healing, disuse osteoporosis, and prednisone osteoporosis (1984)
    Springer
    Calcified tissue international 36 (1984), S. 591-595 
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    ISSN: 1432-0827
    Keywords: Fracture ; (Glucocorticoid ; 1,25(OH)2D3 ; Osteoporosis ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A closed tibial fracture, which was controlled by an intramedullary stainless steel pin, was created in 16 rabbits. Eight rabbits were treated with 75 ng of 1,25(OH)2D3 daily as subcutaneous (s.c.) injections. After three weeks, the fractured tibia resisted a force of 101,7±21.0 Newtons in the control group and 57.3±8.0 Newtons in animals given 1,25(OH)2D3 (m±SE,P〈0.05). In another group of eight rabbits, the left hindleg was immobilized in a plastic splint. Four rabbits were given 75 ng of 1,25(OH)2D3/day s.c. and the effect of immobilization was studied on the calcaneus. Bone ash/cm3 of the calcaneus on the immobilized side was decreased by 11±2% in control rabbits and by 20±2% in the group treated with 1,25(OH)2D3 indicating a more advanced immobilization osteoporosis (m±SE,P〈0.05), which was also demonstrated by studies of bone density. Eighteen rabbits were used in a study of the effects of 1,25(OH)2D3 on the development of prednisolone osteoporosis. The dose of prednisolone was 2.5 mg per day, given by the oral route. After four months, the density of the femur was 1.53±0.02 g/cm2 in control rabbits and 1.42±0.01 in prednisolonetreated animals (P〈0.01). In rabbits additionally given 1,25(OH)2D3, the mean value for bone density was further lowered (n.s.). It appears that 1,25(OH)2D3 exaggerates disuse osteoporosis and prednisolone osteoporosis and impairs fracture healing in rabbits. These results differ from what has been shown earlier with 1,25(OH)2D3 treatment in the rat.
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    URL: http://dx.doi.org/10.1007/BF02405372
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    Oral 1,25(OH)2D3: An effective prophylactic treatment for glucocorticoid osteopenia in rats (1983)
    Springer
    Calcified tissue international 35 (1983), S. 107-110 
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    ISSN: 1432-0827
    Keywords: Calcium ; Glucocorticoid ; Vitamin D ; Osteoporosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Eighty-eight adult male Sprague-Dawley rats were given a diet with either (a) 0.5% Ca and 0.6% P or (b) 0.01% Ca and 0.6% P. Osteopenia was created by adding prednisolone to the diet. The prophylactic effect of oral 1,25(OH)2D3 on the osteopenia was studied. It was found that prednisolone osteopenia in the rat was associated with defective Ca absorption. By giving an oral dose of 1,25(OH)2D3, it was possible to maintain normal Ca absorption during prednisolone treatment and to prevent the bone loss. No significant hypercalcemia or any kidney calcifications were seen. These results are in contrast to earlier findings, in which subcutaneous administration of 1,25(OH)2D3 failed to prevent prednisolone osteopenia because of its tendency to increase bone resorption.
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    URL: http://dx.doi.org/10.1007/BF02405014
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    Basic and clinical evaluation of the measurement of bone resonant frequency (1983)
    Springer
    Calcified tissue international 35 (1983), S. 153-158 
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    ISSN: 1432-0827
    Keywords: Bone resonant frequency ; Osteoporosis ; Osteomalacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A new computerized apparatus was constructed to measure the resonant frequency of human ulnain vivo with high sensitivity and reproducibility. Experimental studies using aluminum bar and dried human bone revealed the importance of the ulna being positioned parallel to the radius, approximately 90 degree flexion of the elbow joint, and minimal muscle activity in order to demonstrate maximum resonant frequency of ulna. Measurement of bone resonance in monkeysin vivo and after removal of the bonein vitro showed good agreement. Product of F (maximum resonant frequency in Hz) and L (ulnar length in cm), FL, indicating the speed of propagation of sound wave through the ulna, showed a significant positive correlation with bone mineral content/bone width (BM/BW) measured by Norland-Cameron apparatus and age-bound decline in both sexes. Patients with osteomalacia and primary hyperparathyroid bone disease tended to have higher FL values than expected from BM/BW. Two-dimensional display of FL and BM/BW thus appears to be useful in distinguishing osteoporosis from osteomalacia better than the use of BM/BW alone.
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    URL: http://dx.doi.org/10.1007/BF02405023
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    Amylin increases bone volume but cannot ameliorate diabetic osteopenia (1995)
    Springer
    Calcified tissue international 56 (1995), S. 54-61 
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    ISSN: 1432-0827
    Keywords: Diabetes mellitus ; Amylin ; Osteoporosis ; Bone mineral metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Amylin is normally secreted in a regulated fashion by the pancreatic β-cells in parallel with insulin and has been reported to have bone-conserving properties. Type I diabetes mellitus results in a low-turnover osteopenia in the presence of decreased amylin, which is in contrast to type II diabetes where less bone loss, in the presence of high amylin levels, occurs. We investigated the effects of amylin on bone mineral metabolism in normal and dibetic (streptozotocin-induced) rats, in order to ascertain whether amylin would modify the streptozotocin-induced diabetic osteopenia. Tenweek-old male Sprague-Dawley rats were randomized as follows: group A (n=18) received normal saline; group B (n=18) received amylin; group C, diabetic rats (n=23), received normal saline; and group D, diabetic rats (n=23), received amylin. Amylin (100 pmol/100 g b. w.) was administered by a daily subcutaneus injection. Double calceinlabeled tibiae were removed for histomorphometric analysis followed sacrifice on day 19. Results showed no difference in blood ionized calcium between groups. Blood glucose remained above 600 mg/dl in the diabetic animals and was not affected by the administration of amylin. Serum osteocalcin, insulin-like growth factor-1 (IGF-1), parathyroid hormone (PTH), and 1,25 dihydroxyvitamin D [1,25(OH)2D] were significantly lower in the diabetic rats compared with control group A by day 19. Amylin produced higher levels of serum osteocalcin in group B on day 9 (P〈0.05) compared with controls but returned to control values (group A) by day 19; no such change occurred in the diabetic group. Amylin administration did not influence IGF-1, 1,25(OH)2D or PTH levels compared with the untreated animals. Analysis of the bone histomorphometry showed a low-turnover osteopenia in the diabetic animals. Amylin administration resulted in a significant increase in bone volume in the normal rats, group B (P〈0.05), but was unable to significantly alter this parameter in the diabetic animals. In conclusion, amylin has a beneficial effect on the bone metabolism of the rat in vivo by increasing bone volume. It is, however, unable to overcome the osteopenia caused by streptozotocin-induced diabetes mellitus at the doses used in this study.
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    URL: http://dx.doi.org/10.1007/BF00298745
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    Investigation of the relationship between osteoporosis and the collagenase gene by means of polymorphism of the 5′upstream region of this gene (1995)
    Springer
    Calcified tissue international 56 (1995), S. 88-91 
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    ISSN: 1432-0827
    Keywords: Allele frequencies ; Collagenase ; Denaturing gradient gel electrophoresis ; Osteoporosis ; Polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Osteoporosis is a slowly progressing disease resulting from an imbalance between bone accretion and degradation. As interstitial collagenase is a key enzyme in the degradatior of bone matrix, we investigated a possible relationship between the collagenase gene and osteoporosis. Analysis of an amplified genomic DNA fragment from-524 to +52 by denaturing gradient gel electrophoresis and sequencing allowed us to detect three dimorphic sites upstream of base-300, one of them leading to a BanI restriction site. None of the sites could be directly associated with osteoporosis. The allele frequencies of the three dimorphic sites were estimated. The interallelic ratios were high, thus providing new useful genetic markers for linkage analysis. When comparing these ratios in osteoporotic and nonosteoporotic subjects, no significant differences could be observed.
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    URL: http://dx.doi.org/10.1007/BF00298750
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    Age changes of spine density in posterior-anterior and lateral projections in normal women (1995)
    Springer
    Calcified tissue international 56 (1995), S. 201-205 
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    ISSN: 1432-0827
    Keywords: Bone densitometry ; Bone ; Osteoporosis ; Aging osteopenia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Bone mineral density (BMD) was measured in 353 healthy white women using dual-energy X-ray absorptiometry (DXA). Measurements were made of both the posterior-anterior (PA) and lateral spine, as well as the proximal femur (neck and Ward's triangle). From age 50 to 80 years, the BMD of the PA spine and femur neck BMD had an 18% diminution (0.6%/year), and BMD of the lateral spine showed about a 35–40% decline (1.4%/year). The Ward's triangle region of the femur was not quite as decreased (30% or 1.1%/year). The BMD decrease associated with aging did not differ as much among sites when expressed relative to the intrapopulation variation rather than as a percentage. The Z-score for PA spine and femur neck BMD (-1.1) was significantly different than that for lateral spine BMD (-1.6); Ward's triangle was intermediate (-1.3), i.e., the lateral spine still showed the highest sensitivity to aging. However, the ability to detect age changes in an individual subject can be increased only if the precision error for lateral spine BMD is not increased to a greater extent than the sensitivity.
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    URL: http://dx.doi.org/10.1007/BF00298610
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    Discrimination of total body bone mineral density measured by dexa in vertebral osteoporosis (1995)
    Springer
    Calcified tissue international 56 (1995), S. 263-267 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Total body ; Bone mineral density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The assessment of bone mineral density (BMD) is the usual study to detect patients at risk for developing osteoporosis. The aim of this study was to compare the discriminative ability of total body BMD and its different subregions with the more usual measurements of BMD of the lumbar spine and femoral neck in women with osteoporotic fractures of the spine. The BMD was determined in 61 osteoporotic (at least one vertebral wedge fracture visible in the lateral X-ray film of the thoracic or lumbar spine) and 61 age-matched control women. Measurements were made by dual X-ray absortiometry (DXA) with a total body scanner. The BMD of the osteoporotic women was significantly lower at all skeletal areas compared with control (P〈0.001). The diminution was less pronounced but still significant at the arms (P〈0.05). The areas with the largest Z score in the osteoporotic group were antero-posterior lumbar spine (-1.78), femoral neck (-1.71), legs (-1.67), and total body (-1.59). There was no significant difference among the Z scores of the four above-mentioned measurements. The Z score of the arms (-0.79), spine (-1.12), and head (-1.29) were significantly lower than the Z score of the total body. The Z score of the pelvis was lower than the Z score of the total body but the difference only approached statistical significance (0.05〉 P〈0.1). The Z score of the anteroposterior lumbar spine (-1.78) was compared with the Z score of the total (-1.12) lumbar (-0.93) and thoracic (-1.38) spine obtained as subregions of the total body. The best differentiation of the two populations was found by measuring the antero-posterior lumbar spine directly (P〈0.01-P〈0.001). In conclusion, the diagnostic differentiation of the total body BMD is similar to that of the anteroposterior lumbar spine and proximal femur measurements. In addition, the measurement of the total body BMD has a lower error and enables simultaneous evaluation of the different subregions of the skeleton as well as the body composition. The BMD of the spine as a subregion of the total body cannot replace the direct evaluation of the anteroposterior lumbar spine.
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    URL: http://dx.doi.org/10.1007/BF00318044
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    Ovariectomy decreases the bone area fraction of the rat mandible (1995)
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    Calcified tissue international 56 (1995), S. 305-310 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Ovariectomy ; Oral bone loss ; Biomechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Although osteoporosis is a major public health concern, the effect of this condition on oral bone has not been determined. Using the ovariectomized rat, we tried to determine if estrogen depletion and aging affect the mandible of the rat. Sixty-one ovariectomized (ovx) and shamoperated (sham) 6-month-old Sprague Dawley rats were divided equally into six groups. The baseline, adult, and old rats were euthanized 14, 114, 200 days post-ovx, respectively. The bone mineral density of the mandible was measured using high resolution dual energy x-ray absorptiometry. The failure load and stiffness of the mandible were measured in three-point bending. The bone area fraction and area moment of inertia of digitized images of mandible sections were measured using image analyzing software. In adult rats, ovx led to a 15% and 28% increase in failure load and stiffness, respectively, but no change in bone area fraction or bone mineral density. In the old rats, ovx led to an 8% decrease in bone area fraction, but no change in failure load, stiffness, or bone mineral density of the mandible. In the ovx rats, aging led to a 20% and 7% decrease in stiffness and bone area fraction of the mandibles in the old rats compared with that in the adult rats. In the adult ovx rats, the increase in structural properties of the mandible may be a consequence of an increase in masticatory function as it has been reported that ovx rats eat approximately 10% more than sham controls. Overall, ovx led to a decrease in bone area fraction in the mandible and a decrease in bone area fraction and stiffness in the mandible of the aging rat. These findings indicate that in this model, estrogen depletion affects the mandible and may contribute to oral bone loss and that this loss may be accentuated with aging.
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    URL: http://dx.doi.org/10.1007/BF00318051
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    Increased bone resorption and decreased bone formation in Chinese patients with hip fracture (1995)
    Springer
    Calcified tissue international 56 (1995), S. 347-349 
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    ISSN: 1432-0827
    Keywords: Acid phosphatase ; Alkaline phosphatase ; Hip fracture ; Osteocalcin ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Biochemical markers of bone formation (bone-specific alkaline phosphatase and osteocalcin) and bone resorption (hydroxyproline excretion and bone isoenzyme of acid phosphatase) were measured in 30 patients (15 M and 15 F) with hip fracture and 30 healthy subjects matched for age and sex. Bone isoenzyme of tartrate-resistant acid phosphatase (TRACP) was measured by a recently developed specific immunoassay. Serum osteocalcin concentration and bone-specific alkaline phosphatase activity were significantly lower and serum TRACP concentration and urinary hydroxyproline excretion were elevated in patients compared with healthy subjects. We suggest that there is reduced bone formation and increased bone resorption in patients with hip fracture.
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    URL: http://dx.doi.org/10.1007/BF00301599
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    Phosphorus-31 in vivo magnetic resonance spectroscopy of bone fails to diagnose osteoporosis (1995)
    Springer
    Calcified tissue international 56 (1995), S. 529-532 
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    ISSN: 1432-0827
    Keywords: Osteoporosis ; Nuclear magnetic resonance pectroscopy ; Phosphorus-31 ; T1 relaxation time ; Bone ; Wrist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The values of in vivo T1 relaxation time (T1) of phosphorus atoms of wrist bone have been measured by phosphorus-31 magnetic resonance spectroscopy (MRS) in 65 menopausal women separated into three groups: (1) agematched women without any paraclinical or clinical osteoporosis; (2) patients with paraclinical osteoporosis detected only by dual photonic absorptiometry; and (3) women with clinical osteoporosis with vertebral fractures. No significant differences were found in T1 values in the presence of paraclinical or clinical osteoporosis as compared to control values. No relationships were found among the T1, the value of the Z-score, the value of bone mineral content, the age of patients, the number of their children, and the age of menopause. Phosphorus-31 magnetic resonance spectroscopy of the wrist fails to separate osteoporotic from nonosteoporotic women and cannot be clinically used at this time to perform a noninvasive diagnosis of osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298583
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    Prevention of postmenopausal bone loss by rectal calcitonin (1995)
    Springer
    Calcified tissue international 56 (1995), S. 539-542 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Calcitonin ; Densitometry ; Menopause ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract A group (150) of healthy women, who had been menopausal for less than 5 years and who had never received any form of treatment to prevent bone loss were entered into a randomized, controlled study comprising three arms. They were randomly allocated to the double-blind administration of five suppositories per week containing either 100 IU of salmon calcitonin or a placebo, or to a group receiving a suppository containing 200 IU of salmon calcitonin three times per week. All women received 500 mg/day of calcium supplementation. After 12 months, bone mineral density (BMD) of the spine, measured by dual energy X-ray absorptiometry, decreased significantly (P〈0.01) in the placebo group by 3.1% (SD: 3.6%) but did not change in the two calcitonin groups [+1.3% (3.5%) with 100 IU/day and +2.3% (4.0%) with 200 IU 3/week]. The differences in response between the placebo group and the two calcitonin groups were significant (P〈0.05), but the difference between the two regimens of calcitonin administration was not. No differences appeared among the three groups for the response at the level of the hip. Evolution of biochemical markers reflecting bone turnover did not differ significantly among groups. Nearly 40% of the women withdrew prematurely because of local (rectal or intestinal) intolerance to repetitive suppositories, with a nonsignificantly different frequency in the placebo or calcitonin groups. We conclude that rectal calcitonin might be an interesting preventive approach against trabecular postmenopausal bone loss but that long-term acceptability of suppositories should be evaluated in view of each patient's sensibility or cultural background.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298586
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    Evolution of spinal bone loss and biochemical markers of bone remodeling after menopause in normal women (1995)
    Springer
    Calcified tissue international 57 (1995), S. 105-110 
    Details
    ISSN: 1432-0827
    Keywords: Menopause ; Bone loss ; Osteoporosis ; Bone densitometry ; Biochemical markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The main objective of this study was to describe longitudinal patterns of spinal bone loss in normal women who undergo a natural menopause. The second objective was to determine if a proportion of women suffer excessively rapid postmenopausal bone loss from the spine. If this was the case it was the aim to devise a means of predicting the women at excess risk; but if all women lost bone at similar rates, the aim was to document changing loss rates over the first 5–8 postmenopausal years. Responding women in six suburban general practices recalled for cervical smears who had their last menstrual period 9–36 months previously were invited to participate in a longitudinal study of bone loss and the biochemical markers plasma osteocalcin and urinary hydroxyproline. Sixty-four subjects agreed to participate, a response rate of 80%. In the ensuing 5 years, six received hormone replacement therapy and are not reported on. The main outcome measures were rates of spinal bone loss over 5 years, measured by dual photon absorptiometry, and radial bone loss over the first 2 years measured to quantitative computed tomography. Spinal bone loss was similar between individuals, with 94% of the variability in the data being accounted for by a statistical model that assumed parallel rates of bone loss. A less restrictive model allowing women to have different rates of spinal bone loss accounted for 12% more of the remaining variance in the data than the previous model. However, rates of radial bone loss were more dissimilar between women than rates of spinal loss. The results of the biochemical data collected serially showed that the plasma osteocalcin rose slowly to a plateau at 5 years postmenopause; in contrast, the hydroxyproline fell progressively with time over the whole period of study. These results were interpreted as being consistent with diminishing rates of bone destruction which gradually reequilibrated with bone formation as time passed after menopause.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298429
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    Ultrasound and dual X-ray absorptiometry densitometry in women with hip fracture (1995)
    Springer
    Calcified tissue international 57 (1995), S. 165-168 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Ultrasound ; Hip fractures ; Bone density ; DXA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract To assess the usefulness of the measurement of the os calcis by ultrasound, a method that probably reflects bone quality as well as density, we have studied 54 women with hip fracture of the proximal femur and a control group. Ultrasound evaluation of the os calcis [broadband ultrasound attenuation (BUA), speed of the sound (SOS), and a combined index (“stiffness”)], and bone mineral density (BMD) determination over the proximal femur by dual X-ray absorptiometry (DXA) were performed. Weight, BMD, and ultrasound values in the hip fracture patients were significantly lower than controls (P〈0.001). The Z-scores for BUA and stiffness were not different than that for femoral neck. Ward's triangle or trochanteric BMD (between-1.7 and -1.5). The odds ratios determined by receiver-operating characteristics (ROC) analysis were greater at the femoral neck (25.1) and BUA (24.4). Intermediate values were found at stiffness (16.9), Ward's triangle (12.8), and trochanter (11.1), and lower values were obtained at SOS (4.2). In turn, patients with trochanteric hip fractures had a significantly lower femoral neck and Ward's triangle BMD, stiffness, and BUA than patients with cervical hip fractures. Comparing a subgroup of 30 women with hip fractures without vertebral fractures with an age-matched group of 87 women with osteoporotic vertebral fractures, both groups were of similar weight and BMD but all ultrasound values were significantly lower in the hip fractures compared with vertebral fracture patients (P〈0.05-P〈0.01). Our findings suggest that in women with hip fractures, ultrasound evaluation of the os calcis has diagnostic sensitivity comparable to DXA of the femur and could be useful to predict hip fracture risk. Ultrasound values are lower in hip fractures compared with vertebral fracture, age-matched women and in older compared with younger hip fracture patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310252
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    Mechanotransduction and the functional response of bone to mechanical strain (1995)
    Springer
    Calcified tissue international 57 (1995), S. 344-358 
    Details
    ISSN: 1432-0827
    Keywords: Bone density ; Calcium channels ; Integrins ; Osteoporosis ; Osteoblasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Mechanotransduction plays a crucial role in the physiology of many tissues including bone. Mechanical loading can inhibit bone resorption and increase bone formation in vivo. In bone, the process of mechanotransduction can be divided into four distinct steps: (1) mechanocoupling, (2) biochemical coupling, (3) transmission of signal, and (4) effector cell response. In mechanocoupling, mechanical loads in vivo cause deformations in bone that stretch bone cells within and lining the bone matrix and create fluid movement within the canaliculae of bone. Dynamic loading, which is associated with extracellular fluid flow and the creation of streaming potentials within bone, is most effective for stimulating new bone formation in vivo. Bone cells in vitro are stimulated to produce second messengers when exposed to fluid flow or mechanical stretch. In biochemical coupling, the possible mechanisms for the coupling of cell-level mechanical signals into intracellular biochemical signals include force transduction through the integrin-cytoskeleton-nuclear matrix structure, stretch-activated cation channels within the cell membrane. G protein-dependent pathways, and linkage between the cytoskeleton and the phospholipase C or phospholipase A pathways. The tight interaction of each of these pathways would suggest that the entire cell is a mechanosensor and there are many different pathways available for the transduction of a mechanical signal. In the transmission of signal, osteoblasts, osteocytes, and bone lining cells may act as sensors of mechanical signals and may communicate the signal through cell processes connected by gap junctions. These cells also produce paracrine factors that may signal osteoprogenitors to differentiate into osteoblasts and attach to the bone surface. Insulin-like growth factors and prostaglandins are possible candidates for intermediaries in signal transduction. In the effector cell response, the effects of mechanical loading are dependent upon the magnitude, duration, and rate of the applied load. Longer duration, lower amplitude loading has the same effect on bone formation as loads with short duration and high amplitude. Loading must be cyclic to stimulate new bone formation. Aging greatly reduces the osteogenic effects of mechanical loading in vivo. Also, some hormones may interact with local mechanical signals to change the sensitivity of the sensor or effector cells to mechanical load.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302070
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    Risk for osteoporosis in black women (1996)
    Springer
    Calcified tissue international 59 (1996), S. 415-423 
    Details
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Bone density ; Race ; Ethnicity ; Fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Models of involutional bone loss and strategies for the prevention of osteoporosis have been developed for white women. Black women have higher bone densities than white women, but as the black population ages there will be an increasingly higher population of black women with osteoporosis. Strategies should be developed to reduce the risk of black women for fragility fractures. Dual energy X-ray absorptiometry measurements of the total body, femur, spine, and radius were performed on 503 healthy black and white women aged 20–80 years. Indices of bone turnover, the calcitrophic hormones, and radioisotope calcium absorption efficiency were also measured to compare the mechanisms of bone loss. The black women had higher BMD values at every site tested than the white women throughout the adult life cycle. Black women have a higher peak bone mass and a slightly slower rate of adult bone loss from the femur and spine, which are skeletal sites comprised predominantly of trabecular bone. Indices of bone turnover are lower in black women as are serum calcidiol levels and urinary calcium excretion. Serum calcitriol and parathyroid hormone levels are higher in black women and calcium absorption efficiency is the same in black and white women, but dietary calcium intake is lower in black women. Black and white women have a similar pattern of bone loss, with substantial bone loss from the femur and spine prior to menopause and an accelerated bone loss from the total skeleton and radius after menopause. The higher values for bone density in black women as compared with white women are caused by a higher peak bone mass and a slower rate of loss from skeletal sites comprised predominantly of trabecular bone. Low-risk strategies to enhance peak bone mass and to lower bone loss, such as calcium and vitamin D augmentation of the diet, should be examined for black women. The risk vs. benefits of hormonal replacement therapy should be determined, especially in older women.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369203
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    UVB radiation and its role in the treatment of postmenopausal women with osteoporosis (1998)
    Springer
    International journal of biometeorology 41 (1998), S. 128-131 
    Details
    ISSN: 1432-1254
    Keywords: Key words Ultraviolet light ; Osteoporosis ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract  In humans, the serum concentration of parathyroid hormone (PTH) is higher in winter than in summer. The increase of PTH can be suppressed by oral vitamin D supplements, which is considered beneficial to those with osteoporosis. The present study investigates whether this effect can also be achieved by serial ultraviolet (UV) irradiation of the skin. In total, 34 women suffering from postmenopausal osteoporosis were included in the open trial. In late winter, 20 patients were irradiated with a spectrum containing UVB, eight times over a period of 4 weeks. The serum concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)2D], PTH, osteocalcin, alkaline phosphatase (AP), calcium and phosphorus were measured before the first, and 2 days after the last, dose of radiation. The data were compared to the controls (n=14, no UV exposure), who were evaluated once at the start of the study and then again 4 weeks later. After UV irradiation the level of 25(OH)D was increased, whilst that of PTH remained unchanged. The serum level of osteocalcin decreased in the control group, but did not change in the group of women who had been exposed to UV radiation. The present study of osteoporotic women does not confirm previous findings in studies of healthy volunteers i.e. that PTH can be suppressed by exposure to UVB radiation in winter. Further studies are required to specify whether there are subgroups of osteoporotic people who may benefit from exposure to UVB radiation during winter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004840050065
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