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  • 1
    Electronic Resource
    Electronic Resource
    Mean wall thickness and formation periods of trabecular bone packets in corticosteroid-induced osteoporosis (1983)
    Springer
    Calcified tissue international 35 (1983), S. 410-417 
    Details
    ISSN: 1432-0827
    Keywords: Bone remodeling ; Histomorphometry ; Corticosteroid therapy ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have compared the mean wall thickness (MWT) and active formation periods (sigmaf(A)) of trabecular bone packets in iliac crest biopsies from 20 patients (7 male, 13 female) with corticosteroid-induced osteoporosis (CS-OP) and 20 age- and sex-matched controls. The trabecular bone volume (TBV) of the CS-OP patients (9.6%±2.2% [SD]) was significantly reduced compared to controls (19.3%±5.1%). The MWT of CS-OP patients (32.7±4.3 µm) was also significantly lower than the control value (48.0±6.2 µm). There was a positive correlation between MWT and TBV in both groups. The mineralization rate (M) of the CS-OP patients (0.54±0.25 µm/day) was within the normal range, and since there was no increase in osteoid seam thickness, so therefore was the osteoblastic appositional rate (OAR). The active formation period of trabecular bone packets (sigmaf(A)=MWT/M) was significantly lower in the CS-OP patients (55.9 ± 14.4 days) than in the control group (68.1 ± 9.4 days). MWT and sigmaf(A) both decreased with age in the control group, whereas in the CS-OP group they were independent of age. We conclude that corticosteroid therapy results in a reduction of the MWT of trabecular bone packets and, consequently, of TBV. In these patients, where the OAR was normal, the reduction in MWT was apparently caused by a shortening of the lifespan of the active osteoblastic population at the basic multicellular unit (BMU) level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405069
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  • 2
    Electronic Resource
    Electronic Resource
    Marrow changes in paraplegic patients (1984)
    Springer
    Calcified tissue international 36 (1984), S. 338-340 
    Details
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405340
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  • 3
    Electronic Resource
    Electronic Resource
    Bone resorption and circulating PTH-like bioactivity in an animal model of hypercalcaemia of malignancy
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 161 (1989), S. 1166-1171 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0006-291X(89)91364-8
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  • 4
    Electronic Resource
    Electronic Resource
    Quantitative analysis of T6-positive Langerhans cells in human skin cancers (1986)
    Springer
    Virchows Archiv 410 (1986), S. 57-63 
    Details
    ISSN: 1432-2307
    Keywords: Langerhans cells ; Basal cell carcinomas ; Squamous cell carcinomas ; Quantitative analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Epidermal Langerhans cells (LC) are required for antigen-presentation and for stimulating antigen-specific T cell activation. Similar functions may be important in the immune response to malignant skin tumours. Monoclonal anti-T6 antibody was used to examine LC population in basal and squamous cell carcinomas. Positive control labeling was performed with monoclonal anti-HLA-DR antibody. The number of T6-positive LC per mm2 of section was significantly decreased (p〈0.01) in the tumour group in comparison with a sex and age-matched control group. The number of sun-exposed and covered regions was taken into consideration in each respective group. Within the tumours, LC were found more frequently in the tumour periphery and in most differentiated tumour areas (horn pearls) than in the rest of the tumour mass. T6-positive LC were rarely found in the dermis. Moreover, LC exhibited morphological changes in specimens from tumours. Staining with anti-HLA-DR antibody revealed less numerous positive cells within tumour nests than labeling with OKT6. A relationship between T6-positive LC quantities and extent of HLA-DR-positive infiltrates around tumours could not be established. These results suggest that immunological surveillance of neoantigen-bearing tumour cells may be impaired in skin cancer. A reason for the reduced LC number may be an altered microenvironment in tumour tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00710906
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  • 5
    Electronic Resource
    Electronic Resource
    Fractal Analysis of Bone Texture on Os Calcis Radiographs Compared with Trabecular Microarchitecture Analyzed by Histomorphometry (1998)
    Springer
    Calcified tissue international 63 (1998), S. 121-125 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Fractal analysis—Os calcis—Radiographs—Histomorphometry—Microarchitecture.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Microarchitecture of trabecular bone is an important determinant of bone fragility; to date, its evaluation requires bone biopsy with histomorphometry analysis. Methods of noninvasive characterization of trabecular bone microarchitecture are in development and we have developed and validated a bone texture analysis applied to bone radiographs and based on fractal geometry. The aim of our study was to compare this fractal analysis of trabecular bone texture on radiographs to the trabecular microarchitecture analyzed by bone histomorphometry on os calcis biopsies. Thirty eight ossa calcis from 19 human cadavers were studied. Fractal analysis of the trabecular bone of os calcis radiographs was performed by the maximum likelihood estimator following the fractional brownian motion model. The ossa calcis were dissected, then transcortical biopsy cores focused on the fractal analysis region of interest were obtained. Structural and connectivity parameters were measured with both automatic and semiautomatic analyzers. We have found a significant relationship between the fractal Hmean parameter and structural histomorphometric indices; the best correlation was found with trabecular separation (r =−0.55; P= 0.0004). Based on a stepwise regression analysis, trabecular spacing and trabeculae number together would explain 38% of the variance of the fractal parameter. Although the relationship with connectivity indices was poor, our fractal analysis of os calcis trabecular bone texture on radiographs seemed to partially reflect the trabecular bone microarchitecture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900501
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  • 6
    Electronic Resource
    Electronic Resource
    Gastrointestinal calcium absorption and dietary calcium load: Relationships with bone remodelling in vertebral osteoporosis (1995)
    Springer
    Osteoporosis international 5 (1995), S. 14-22 
    Details
    ISSN: 1433-2965
    Keywords: Bone histomorphometry ; Calcium-47 ; Calcium absorption ; Osteoporosis ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Patients with vertebral osteoporosis have a wide range of bone loss rates, bone remodelling rates and capacities for gastrointestinal (GI) calcium absorption. To test the hypothesis that variations in GI absorptive capacity determine rates of bone loss or remodelling, we have sought relationships betwen calcium absorption or vitamin D metabolite levels on the one hand and rates of cancellous and cortical bone loss (measured by serial quantiative computed tomography in the radius;n=25) or indices of bone remodelling in tetracycline-prelabelled transiliac biopsies (n=41) on the other, in a sequential untreated group. Calcium absorption (net and true) was measured in 18-day balances and by a two-isotope deconvolution method (fractional absorption and maximum absorption rate, MAR). There was no significant seasonal effect on any of these four measures of calcium absorption (variance ratio,F=0.52–1.61,p〉0.1) or on 1,25-dihydroxyvitamin D levels (F=0.13,p〉0.1; range 11–69 pg/ml), notwithstanding the expected seasonal effect on 25-hydroxyvitamin D levels (mean 18.7 ng/ml, zenith mid July, semi-amplitude 7.5 ng/ml;F=6.82,p〈0.01). Neither this metabolite nor 1,25-dihydroxyvitamin D correlated with any index of calcium absorption (p〉0.1). No measure of calcium absorption (or intake) had a significant relationship with radial cortical or cancellous bone loss (p all 〉0.1) but cancellous bone loss was associated with the rate of endogenous calcium excretion (r=0.50,p〈0.05). A positive relationship between 25-hydroxyvitamin D and unlabelled osteoid surface (a marker of reduced blast vigour) persisted after adjustment for season (Student'st=2.70,p〈0.01) but did not reflect 1,25-dihydroxyvitamin D levels. This study did not address the question of whether reduced GI calcium absorption has a uniform effect on bone remodelling in osteoporosis. However, variations in capacity for calcium absorption are unlikely to be responsible for the heterogeneity in bone loss and remodelling rates seen in vertebral osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01623653
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  • 7
    Electronic Resource
    Electronic Resource
    Influence of anthropometric parameters on ultrasound measurements of os calcis (1995)
    Springer
    Osteoporosis international 5 (1995), S. 371-376 
    Details
    ISSN: 1433-2965
    Keywords: Anthropometric parameters ; BUA ; SOS ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Few data have been published concerning the influence of height, weight and body mass index (BMI) on broadband ultrasound attenuation (BUA), speed of sound (SOS) and Lunar “stiffness” index, and always in small population samples. The first aim of the present cross-sectional study was to determine whether anthropometric factors have a significant influence on ultrasound measurements. The second objective was to establish whether these parameters have real effect on bone or whether their infuence is due only to measurement errors. We measured, in 271 healthy French women (mean age 77±11 years; range 31–97 years), the following parameters: age, height, weight, lean and fat body mass, heel width, foot length, knee height and height of the external malleolus (HEM). Simple linear regression analyses between ultrasound and anthropometric parameters were performed. Age, height and heel width were significant predictors of SOS; age, height, weight, foot length, heel width, HEM, fat mass and lean mass were significant predictors of BUA; age, height, weight, heel width, HEM, fat mass and lean mass were significant predictors of stiffness. In the multiple regression analysis, once the analysis had been adjusted for age, only heel width was a significant predictor for SOS (p=0.0007), weight for BUA (p=0.0001), and weight (p=0.0001) and heel width (p=0.004) for the stiffness index. Besides their statistical meaning, the regression coefficients have a more clinically relevant interpretation which is developed in the text. These results confirm the influence of anthropometric factors on the ultrasonic parameter values, because BUA and SOS were in part dependent on heel width and weight. The influence of the position of the transducer on the calcaneus should be taken into account to optimize the methods of measurement using ultrasound.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01622259
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  • 8
    Electronic Resource
    Electronic Resource
    Human parathyroid peptide treatment of vertebral osteoporosis (1993)
    Springer
    Osteoporosis international 3 (1993), S. 199-203 
    Details
    ISSN: 1433-2965
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies have shown that treatment with daily injections of human parathyroid peptide (hPTH) 1-34 increase axial cancellous bone mass partially at the expense of peripheral cortical bone. In the present work the same hPTH 1-34 regime given for 12 months has been combined with oestrogen or nandrolone therapy to control peripheral bone resorption. Spinal and iliac cancellous (but not cortical) bone increased by 40%–50% above initial values while no perceptible changes occurred in radial cortical or cancellous bone. The evidence of radiokinetic and histomorphometric studies performed before and in the last months of treatment suggested that bone remodeling had proceeded through a transient anabolic phase with increased activation, but that activation had become normal after 11–12 months in the cancellous bone of the ilium whereas it continued to be raised elsewhere in the skeleton. It is concluded that in combination with oestrogens, hPTH peptides given daily injections hold great promise for the treatment of patients with osteoporosis who have already lost substantial amounts of spinal cancellous bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01621906
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  • 9
    Electronic Resource
    Electronic Resource
    Can we stop bone loss and prevent hip fractures in the elderly? (1994)
    Springer
    Osteoporosis international 4 (1994), S. S71 
    Details
    ISSN: 1433-2965
    Keywords: Calcium ; Hip fracture ; Osteoporosis ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The two main determinants of hip fractures are falls and bone loss leading to an intrinsic femoral fragility. Substantial femoral bone loss continues throughout old age, with a continuous and exponential increase in the risk of hip fracture; thus any reduction or arrest of this loss will induce an important reduction in the incidence of hip fracture. Preventive measures may be achieved during childhood by increasing peak bone mass with calcium and exercise, by using long-term estrogen replacement therapy after menopause, but also by using vitamin D and calcium supplements for late prevention in the elderly. Vitamin D insufficiency and a deficit in calcium intake are very common in the elderly living either in institutions or at home and the cumulative response to these deficits is a negative calcium balance which stimulates parathyroid hormone secretion. This senile secondary hyperparathyroidism is one of the determinants of femoral bone loss and can be reversed by calcium and vitamin D supplements. We have shown in a 3-year controlled prospective study that the daily use of supplements (1.2 g calcium and 800 IU vitamin D3) given in a large population of 3270 elderly ambulatory women living in nursing homes reduced the number of hip fractures by 23% (intention-to-treat analysis). In parallel, serum parathyroid hormone concentrations were reduced by 28% and low baseline serum 25-hydroxy vitamin D concentration returned to normal values. After 18 months of treatment the bone density of the total proximal femoral region had increased by 2.7% in the vitamin D3-calcium group and decreased by 4.6% in the placebo group (p〈0.001). This prevention is safe and can be recommended for people living in institutions. It could also be useful in other elderly subjects at particular risk due to a low calcium intake, an absence of solar exposure, a low femoral bone density, a high serum parathyroid hormone concentration, a low serum 25-hydroxyvitamin D concentration and a previous history of falls. Prospective studies are needed for further evaluation of these risk factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01623440
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  • 10
    Electronic Resource
    Electronic Resource
    High-Resolution Computed Tomography for Architectural Characterization of Human Lumbar Cancellous Bone: Relationships with Histomorphometry and Biomechanics (1999)
    Springer
    Osteoporosis international 10 (1999), S. 353-360 
    Details
    ISSN: 1433-2965
    Keywords: Key words:High-resolution computed tomography – Histomorphometry – Human cancellous bone – Mechanical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The aim of the present study on human vertebral cancellous bone was to validate structural parameters measured with high-resolution (150 μm) computed tomography (HRCT) by referring to histomorphometry and to try to predict mechanical properties of bone using HRCT. Two adjacent vertical cores were removed from the central part of human L2 vertebral body taken after necropsy in 22 subjects aged 47–95 years (10 women, 12 men; mean age 79 ± 14 years). The right core was used for structural analysis performed by both HRCT and histomorphometry. Two cancellous bone specimens were extracted from the left core: a cube for HRCT and a compression test, and a cylinder for a shear test. Significant correlations were found between HRCT and histomorphometric measurements (BV/TV, trabecular thickness, separation and number, and node-strut analysis), but with higher values for most of the tomographic parameters (BV/TV and trabecular thickness determined by HRCT were overestimated by a factor 3.5 and 2.5 respectively, as compared with histomorphometry). The maximum compressive strength and Young’s modulus were highly correlated (ρ= 0.99, p〈0.0005). Significant correlation was obtained between bone mineral density (determined using dual-energy X-ray absorptiometry) and the maximum compressive strength (ρ= 0.64, p= 0.002). In addition the maximum compressive strength and architectural parameters determined by HRCT or histomorphometry showed significant correlations (e.g., for HRCT, BV/TV: ρ = 0.88, p〈0.0005, N.Nd/TV: ρ= 0.73, p〈0.001). The shear strength was significantly correlated with BV/TV (ρ= 0.62, p= 0.002), Tb.Sp (ρ=−0.58, p= 0.004) and TSL (ρ= 0.55, p= 0.006) measured by HRCT. In conclusion, an HRCT system with 150 μm resolution is not sufficient to predict the true values of the structural parameters measured by histomorphometry, although high correlations were found between the two methods. However, we showed that a resolution of 150 μm allowed us to predict the mechanical properties of human cancellous bone. In vivo peripheral systems with such a resolution should be of interest and would deliver an acceptable radiation dose to the patient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001980050240
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