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Biomedical subjects

M Amling

Publications and source records attributed to M Amling.

At least 55 records · Page 3Linked to original sources
PubMed1997

Targeted ablation of the vitamin D receptor: an animal model of vitamin D-dependent rickets type II with alopecia.

Vitamin D, the major steroid hormone that controls mineral ion homeostasis, exerts its actions through the vitamin D receptor (VDR). The VDR is expressed in many tissues, including several tissues not thought to play a role in mineral metabolism. Studies in kindreds with VDR mutations (vitamin D-dependent rickets type II, VDDR II) have demonstrated hypocalcemia, hyperparathyroidism, rickets, and osteomalacia. Alopecia, which is not a feature of vitamin D deficiency, is seen in some kindreds. We have generated a mouse model of VDDR II by targeted ablation of the second zinc finger of the VDR DNA-binding domain. Despite known expression of the VDR in fetal life, homozygous mice are phenotypically normal at birth and demonstrate normal survival at least until 6 months. They become hypocalcemic at 21 days of age, at which time their parathyroid hormone (PTH) levels begin to rise. Hyperparathyroidism is accompanied by an increase in the size of the parathyroid gland as well as an increase in PTH mRNA levels. Rickets and osteomalacia are seen by day 35; however, as early as day 15, there is an expansion in the zone of hypertrophic chondrocytes in the growth plate. In contrast to animals made vitamin D deficient by dietary means, and like some patients with VDDR II, these mice develop progressive alopecia from the age of 4 weeks.

Alopecia↗
PubMed1997

Bcl-2 lies downstream of parathyroid hormone-related peptide in a signaling pathway that regulates chondrocyte maturation during skeletal development.

Parathyroid hormone-related peptide (PTHrP) appears to play a major role in skeletal development. Targeted disruption of the PTHrP gene in mice causes skeletal dysplasia with accelerated chondrocyte maturation (Amizuka, N., H. Warshawsky, J.E. Henderson, D. Goltzman, and A.C. Karaplis. 1994. J. Cell Biol. 126:1611-1623; Karaplis, A.C., A. Luz, J. Glowacki, R.T. Bronson, V.L.J. Tybulewicz, H.M. Kronenberg, and R.C. Mulligan. 1994. Genes Dev. 8: 277-289). A constitutively active mutant PTH/PTHrP receptor has been found in Jansen-type human metaphyseal chondrodysplasia, a disease characterized by delayed skeletal maturation (Schipani, E., K. Kruse, and H. Jüppner. 1995. Science (Wash. DC). 268:98-100). The molecular mechanisms by which PTHrP affects this developmental program remain, however, poorly understood. We report here that PTHrP increases the expression of Bcl-2, a protein that controls programmed cell death in several cell types, in growth plate chondrocytes both in vitro and in vivo, leading to delays in their maturation towards hypertrophy and apoptotic cell death. Consequently, overexpression of PTHrP under the control of the collagen II promoter in transgenic mice resulted in marked delays in skeletal development. As anticipated from these results, deletion of the gene encoding Bcl-2 leads to accelerated maturation of chondrocytes and shortening of long bones. Thus, Bcl-2 lies downstream of PTHrP in a pathway that controls chondrocyte maturation and skeletal development.

Animals↗
PubMed1997

The thickness of human vertebral cortical bone and its changes in aging and osteoporosis: a histomorphometric analysis of the complete spinal column from thirty-seven autopsy specimens.

The object of this study was to analyze the cortical thickness (Ct.Th) of the ventral and dorsal shell of the vertebral bodies throughout the human spine in aging and in osteoporosis. Therefore, the complete front column of the spine of 26 autopsy cases (aged 17-90, mean 42 years) without diseases affecting the skeleton and of 11 cases (aged 58-92, mean 77 years) with proven osteoporosis were removed. A sagittal segment prepared through the center of all vertebral bodies was undecalcified, embedded in plastic, ground to a 1 mm thick block, and stained using a modification of the von Kossa method. The analysis included the measurement of the mean cortical thickness of both the ventral and dorsal shell, respectively (from the third cervical to the fifth lumbar vertebral body). The qualitative investigation of the structure of the cortical ring completed the analysis. The presented data revealed a biphasic curve for both the ventral and dorsal shell, skeletally intact with high values of the cortical thickness in the cervical spine (285 microm), and a decrease in the thoracic (244 microm) and an increase in the lumbar spine (290 microm). The mean thickness of the ventral shell is in general greater than the thickness of the dorsal shell in both skeletally normal and osteoporotic cases. The cortical thickness of the spine showed no gender-specific differences (p = NS). There was a slight decrease of the cortical thickness with aging; however, this decrease and the correlation of cortical thickness to age was only significant below vertebral body T8 (r = 0.225-0.574; p(r) < 0.05-0.005). Most interestingly, however, osteoporosis presents itself with a highly significant loss of cortical thickness throughout the whole spine. This decrease of cortical thickness was more marked in the dorsal shell (p < 0.05) than in the ventral shell (ventral from C3 to T6 [p < 0.05] below T6 [p = NS]). We therefore conclude that in osteoporosis the loss of spinal bone mass is not only a loss of trabecular structure but also a loss of cortical thickness. Furthermore, these results may explain the development of regions of least resistance within the spine in aging and the clustering of osteoporotic fractures in the lower thoracic and lumbar spine.

Adolescent↗
PubMed1997

P-glycoprotein expression in high grade central osteosarcoma and normal bone cells. An immunohistochemical study.

One important mechanism by which multidrug resistance is mediated is the mdr1 gene product, P-glycoprotein (Pgp). Even though chemotherapy, in the treatment of high grade central osteosarcoma (hgc-OS), has led to dramatic improvements in survival rate, a certain percentage of patients still show only a poor response to chemotherapy. To further characterize a potential connection between Pgp and chemotherapy as well as the role of Pgp in tumorigenesis of osteosarcoma, we analyzed Pgp-expression in hcg-OS. Immunohistochemistry was performed on 68 hgc-OS samples from 58 patients using the monoclonal antibody JSB-1; in addition, Pgp-expression in normal bone cells was studied in 5 human epiphyseal growth plates. 70.5% of all cases stained positive for P-glycoprotein, while 29.5% of the cases were negative. Cases investigated after chemotherapy showed a higher incidence (82.9%) of positive P-glycoprotein immunostaining than cases prior to chemotherapy (64.4%). The Pgp-expression of 34 biopsies was compared with chemotherapy, as determined at the surgical specimen. In these cases, however, no correlation could be established between P-glycoprotein expression of the biopsy and the later response to chemotherapy. 48.4% of the cases with biopsies, initially positive for Pgp, showed a good response in the surgical specimen, while only 27.2% of Pgp-positive biopsies were later classified as non-responders. In the normally growing skeleton, positive immunostaining was detected in the area of mineralization of epiphyseal growth plates. Osteoclasts, hypertrophic chondrocytes, and cuboidal osteoblasts showed Pgp-expression, while there was a lack of Pgp in the majority of osteocytes and chondrocytes in the resting and proliferating zone. These data therefore suggest that P-glycoprotein expression in hgc-OS resembles, at least in part, the phenotype of active bone cells. These results may explain why P-glycoprotein, by using immunohistochemistry, in biopsies of osteosarcomas is insufficient to predict the response to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

c-Cbl is downstream of c-Src in a signalling pathway necessary for bone resorption.

The primary defect in mice lacking the c-src gene is osteopetrosis, a deficiency in bone resorption by osteoclasts. Osteoclasts express high levels of the c-Src protein and the defect responsible for the osteopetrotic phenotype of the c-src-deficient (src-) mouse is cell-autonomous and occurs in mature osteoclasts. However, the specific signalling pathways that require c-Src expression for normal osteoclast activity have not been elucidated. We report here that the proto-oncogene product c-Cbl is tyrosine-phosphorylated in a Src-dependent manner in osteoclasts, where the two proteins colocalize on some vesicular structures. In vitro bone resorption by osteoclast-like cells (OCLs) is inhibited by both c-src and c-cbl antisense oligonucleotides. Furthermore, tyrosine phosphorylation of c-Cbl and the localization of c-Cbl-containing structures to the peripheral cytoskeleton are impaired in resorption-deficient c-src- OCLs, as well as in wild-type OCLs that have been treated with c-src antisense oligonucleotides. These results indicate that c-Cbl may act downstream of c-Src in a signalling pathway that is required for bone resorption.

3T3 Cells↗
PubMed1996

Targeted overexpression of parathyroid hormone-related peptide in chondrocytes causes chondrodysplasia and delayed endochondral bone formation.

Parathyroid hormone-related peptide (PTHrP) was initially identified as a product of malignant tumors that mediates paraneoplastic hypercalcemia. It is now known that the parathyroid hormone (PTH) and PTHrP genes are evolutionarily related and that the products of these two genes share a common receptor, the PTH/PTHrP receptor. PTHrP and the PTH/PTHrP receptor are widely expressed in both adult and fetal tissues, and recent gene-targeting and disruption experiments have implicated PTHrP as a developmental regulatory molecule. Apparent PTHrP functions include the regulation of endochondral bone development, of hair follicle formation, and of branching morphogenesis in the breast. Herein, we report that overexpression of PTHrP in chondrocytes using the mouse type II collagen promoter induces a novel form of chondrodysplasia characterized by short-limbed dwarfism and a delay in endochondral ossification. This features a delay in chondrocyte differentiation and in bone collar formation and is sufficiently marked that the mice are born with a cartilaginous endochondral skeleton. In addition to the delay, chondrocytes in the transgenic mice initially become hypertrophic at the periphery of the developing long bones rather than in the middle, leading to a seeming reversal in the pattern of chondrocyte differentiation and ossification. By 7 weeks, the delays in chondrocyte differentiation and ossification have largely corrected, leaving foreshortened and misshapen but histologically near-normal bones. These findings confirm a role for PTHrP as an inhibitor of the program of chondrocyte differentiation. PTHrP may function in this regard to maintain the stepwise differentiation of chondrocytes that initiates endochondral ossification in the midsection of endochondral bones early in development and that also permits linear growth at the growth plate later in development.

Animals↗
PubMed1996

Heterogeneity of the skeleton: comparison of the trabecular microarchitecture of the spine, the iliac crest, the femur, and the calcaneus.

The objective of this study was to elucidate the structure of cancellous bone and its age-related changes at different skeletal sites. Therefore, the lumbar spine, iliac crest, femur, and calcaneus of 12 age- and sex-matched skeletal healthy autopsy cases (6 females, 6 males, aged 28-84 years, mean 54 years) were removed. The following analysis includes an evaluation of the trabecular bone volume (BV/TV, %) and the trabecular interconnection (TBPf, mm-1) as well as a qualitative investigation of the structure of trabecular bone. BV/TV shows the following mean values: lumbar spine, 8.3% (+/- 0.8%); iliac crest, 11.5% (+/- 1.6%); intertrochanteric, 10.2% (+/- 1.2%); femoral neck, 15.8% (+/- 1.6%); and calcaneus, 15.4% (+/- 2.0%). There are significant differences between the BV/TV of the femoral neck and that of the lumbar spine as well as between that of the calcaneus and the lumbar spine (p < 0.01). However, a positive correlation can be seen between the bone mass of the spine and that of all other investigated sites (r = 0.67 to r = 0.80; pr < 0.1). The trabecular interconnection of the lumbar spine (2.7 mm-1, SEM +/- 0.2 mm-1) and the femoral neck (0.3 mm-1, SEM +/- 0.3 mm-1) differs significantly. Only these two sites show a significant positive correlation of TBPf (r = 0.60; pr < 0.1). Age-dependent alteration of the spine and the femoral neck in bone mass and bone structure is nearly the same. The trabecular microarchitecture of the iliac crest varies systematically. A region 4-10 cm behind and 1-3 cm below the anterior superior iliac spine turns out to be the most suitable biopsy site because of its closest relation to the lumbar bone mass. However, drawing information about the trabecular interconnection within the lumbar spine by measurement of the iliac crest at any site seems to be impossible. The horizontal specimens reveal a vertical running tubular spongiosa pattern that is arranged in concentric rings starting from the dorsal shell like a honeycomb. The comparison of TBPf in horizontal and vertical planes and its age-related changes indicates the age-related bone loss to be predominantly a loss of horizontal trabeculae. Thus, the presented data provide further information about the skeletal distribution and heterogeneity of the trabecular microarchitecture.

Adult↗
PubMed1996

Architecture and distribution of cancellous bone yield vertebral fracture clues. A histomorphometric analysis of the complete spinal column from 40 autopsy specimens.

The objective of this study was to analyze the structure of cancellous bone and its significance for vertebral fractures. Therefore, the complete spinal column from 40 autopsy cases (18 without diseases affecting the skeleton and 12 osteoporotic) was removed and sectioned in the sagittal plane to a thickness of 1 mm. A surface-stained block grinding technique allowed combined two- and three-dimensional histomorphometric analysis, which included an evaluation of the trabecular bone volume (BV/TV, in %) and the trabecular interconnection (TBPf, in mm). In addition, qualitative investigation of the structure of trabecular bone was done. The distribution of trabecular bone volume within the spinal column of a normal skeleton shows a curve, with the highest values in the cervical spine and a decline in the thoracic and lumbar spine. Osteoporosis presents itself with a pathologically diminished trabecular bone volume, whereas the distribution within the spine is comparable to that of the controls. Osteoporotic patients show an apparently reduced trabecular interconnection. It is important that the measured values for TBPf are not only in general higher, but also more widely dispersed. The age-related decrease of trabecular bone mass is due to the transformation from plates to rods. This is quantitatively indicated by the close correlation of BV/TV and TBPf (P < 0.001, r = 0.85). The bone loss in osteoporosis is a loss of structure and a loss of whole trabeculae, which is caused by perforations. It involves a gradual change from normal bone. However, the polyostic heterogeneity in osteoporosis is immense. These structural differences demonstrate the development of regions of least resistance within the spine, serving as an explanation of osteoporotic fractures. Due to the polyostotic heterogeneity it is impossible to define a threshold mineral content for crash fractures by diagnostic measurements at any reference site.

Adolescent↗
PubMed1996

[Morphologic characteristics of chondroblastoma. A retrospective study of 56 cases of the Hamburg bone tumor register].

Representing only about 1% of all primary bone tumors, chondroblastoma constitutes a very rare bone tumor entity. 56 cases of chondroblastoma, that had been collected by the Hamburg Bone Tumor Registry from 1972 to 1995, were examined histologically together with the radiological and clinical findings. In addition immunohistochemistry with antibodies against S 100, PGM1, LCA and the proliferationmarker MIB 1 was performed. The mean age was 20.4 years and male patients being the majority with a gender ratio of 2.7:1. Predominant localisation was the epiphyses of the long bones, although almost 40% of the tumors were located at untypical sites. Usually a well-circumscribed lysis could be seen on plain X-Ray examination, however partial cortical destruction could be observed in one third of the cases. Histologically characteristic was a polygonal cell component with a weblike chonroid matrix, sometimes with a plane-like appearance. 5 cases showed a distinct nuclear polymorphism making a distinction from osteosarcoma difficult. Using immunohistochemistry all tumors except for one showed positive reaction for S 100 protein. Although the histogenesis of chondroblastoma is not completely understood, morphological findings as well as the observed reactivity with the S 100 protein indicate the chondroid origin. No reactivity for PGM 1 (CD 68) or LCA could be detected. All chondroblastoma showed a low rate of proliferation, thereby being distinguishable from high malignant bone tumors. In general chondroblastoma show a benign biological behavior. Different behavior was observed in 2 cases. One relapse located in the pelvis revealed local aggressive growth while in another case in the humerus a malignant transformation had taken place.

Adolescent↗
PubMed1996

[P-glycoprotein expression in osteosarcoma].

One of the mechanisms by which multidrug resistance is mediated, is the mdr1 gene product, P-glycooprotein. Immunohistochemistry was performed for 63 osteosarcomas of 54 patients to investigate P-glycoprotein expression using the monoclonal antibody JSB-1. Most of the patients were children or adolescents who had received treatment under the framework of the Cooperative Osteosarcoma Study Group. In addition P-glycoprotein expression was assayed in five growth plates. Of all cases 68.5% stained positive for P-glycoprotein. Cases that had received chemotherapy showed a higher incidence (80.9%) of positive P-glycoprotein immunostaining than cases that had not received chemotherapy (66.6%). No relation could be established between P-glycoprotein expression and the response to chemotherapy, since the majority of P-glycoprotein positive biopsies showed a good response in the surgical specimen after chemotherapy. Furthermore, 42.9% of P-glycoprotein negative biopsies were classified as non-responders in the later surgical specimen. In addition to P-glycoprotein expression in osteosarcomas positive immunostaining was also detected in osteoblasts, osteocytes, osteoclasts as well as in some chondroblasts. The results indicate that P-glycoprotein expression in osteosarcomas also exists prior to chemotherapy and resembles the phenotype of normal bone tissue. However, the determination of P-glycoprotein by using immunohistochemistry in biopsies of osteosarcomas cannot predict the response to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

[Solitary bone cysts. Morphologic variation, site, incidence and differential diagnosis].

Analysis of 402 solitary bone cysts demonstrates the wide morphological variation of this cystic lesion with regard to histology and radiology. Aside from metaphyseal location in femur (33%) and humerus (23%), solitary bone cysts are also often located in calcaneus (11%), tibia (11%) and pelvis (10%). Most patients are in the second decade of life. Differentiation between this benign lesion and malignant bone tumors is very important in daily clinical routine. The diagnosis cannot be based solely on radiological findings because of the variation of solitary bone cysts and the special forms, such as calcifying solitary bone cyst. Therefore, exact histological diagnosis is of particular importance.

Adolescent↗
PubMed1996

[Spongiosa structure and polyostotic heterogeneity in osteoporosis. Mechanism of bone transformation, morphology, clinical significance].

Osteoporosis is the most frequent generalized bone disease. The clinical expression of postmenopausal osteoporosis is characterized by spontaneous fractures of the vertebral bodies which affect mainly the trabecular bone structure. Thus the morphological bone transformation in osteoporosis is of clinical relevance. The object of this study was to analyze quantitatively and qualitatively the distribution of three-dimensional structure of cancellous bone in the human spine in osteoporosis. Therefore the complete anterior column of the spine and bone biopsies of the iliac crest of 11 autopsy cases with proven osteoporosis and 26 autopsy cases without primary or secondary bone disease were removed. A 1-mm-thick prepared sagittal section through the center of all vertebral bodies was embedded undecalcified in plastic and stained on the surface using a modification of the von Kossa method. This technique allowed combined two- and three-dimensional measurements simultaneously; these included evaluation of trabecular bone volume, trabecular interconnection, trabecular thickness, and trabecular number. The quantitative spine deformity index and qualitative analysis of the trabecular bone structure completed the investigation. The bone loss in osteoporosis is a loss of structure and the loss of whole trabeculae caused by perforations. The age-related decrease of trabecular bone mass is due to the transformation from plates to rods. Patient with osteoporosis show pathologically diminished trabecular bone volume and apparently reduced trabecular interconnection, while trabecular thickness and trabecular number show age-dependent change. The polyostotic heterogeneity in osteoporosis is immense. Neighboring vertebral bodies show differences of up to 100% in bone volume and bone structure. Due to this fact it is impossible to define a threshold for osteoporotic fractures. At the moment the transformation and loss of trabecular bone structure in osteoporosis is assumed to be irreversible; therefore, early prophylaxis is necessary to prevent clinical manifestations of these changes of bone.

Adolescent↗
PubMed1996

[Periosteal osteosarcoma. Histologic characteristics, preparation technique, growth pattern and differential diagnosis].

Periosteal osteosarcoma is a distinct bone tumor entity with characteristic morphological features within the group of juxtacortical osteosarcoma. Periosteal osteosarcoma is predominantly located in the long tubular bones, especially in the tibia and femur and is situated on the outer circumference of the tumor-bearing bone (saucerization phenomenon). In contrast to parosteal osteosarcoma, periosteal osteosarcoma is less differentiated and is believed to have a worse prognosis. In this work the histological features are described with predominantly chondroblastic differentiation of 14 cases with periosteal osteosarcoma. A horizontal preparation technique of periosteal osteosarcoma specimens allows comparison with computed tomography and is the optimal method to detect an invasion of the medullary cavity. Further studies are necessary to clarify if neoadjuvant chemotherapy could improve the prognosis of certain patients.

Adolescent↗
PubMed1996

[Cell biology of osteoclasts and molecular mechanisms of bone resorption].

The maintenance of a normal skeletal shape and bone mass closely depends on a normal osteoclastic activity, as do bone growth and repair. Thus, the improvement of our means of therapeutic intervention will depend on our better understanding of the molecular basis of bone resorption and of the cellbiology of the osteoclast. This review-article presents our current opinion of the molecular mechanisms of bone resorption by the osteoclast. After describing the morphological features of the osteoclast, aspects as cell mobility, attachment, enzymesynthesis, transmembrane transport, osteoclast differentiation and function, as well as the protooncogenes c-src and c-cbl and their role for bone resorption are presented in detail.

Animals↗
PubMed1995

Microcallus formations of the cancellous bone: a quantitative analysis of the human spine.

Microcallus formations are demonstrable in nearly all spongy bone by means of suitable preparation techniques. Histologically, these structures are immature fibrous bone. Their genesis, frequency, and importance are largely unknown. To address these issues, 26 normal human spines, 11 osteoporotic spines, and different parts of the skeleton (femur head, iliac crest) were investigated for microcallus using a new preparation technique--allowing a combined 2- and 3-dimensional analysis. According to our analysis, microcallus formation occurs frequently in persons older than 45 years of age. These formations are mainly localized in the lower thoracic and lumbar spine and are obviously more frequent in females than in males. In individuals with a trabecular bone volume (BV/TV) in the spine below 11%, microcallus formations occur regularly. But the number of microcallus formations depends more on the microarchitecture of the cancellous bone (trabecular bone pattern factor, TBPf), than on individual trabecular parameters (trabecular number, TbN; trabecular bone volume, BV/TV; and trabecular thickness, TbTh). In about 33% of cases microfractures are demonstrable in the center of the microcallus formation. It is unclear whether microcallus may be the result of a nontraumatic process. In therapy studies the bone mass could be misrepresented due to the amount of microcallus. Although it indicates instability of the bone structure, microcallus formation is not only a negative mechanism, but stabilizes and regenerates the bone tissue. Furthermore, complete new trabeculae can be formed due to bridges of microcallus between the remnant trabeculae. Osteoporosis is not the result of an inability to form microcallus formations.

Adolescent↗
PubMed1995

Calcifying solitary bone cyst: morphological aspects and differential diagnosis of sclerotic bone tumours.

Fourteen solitary bone cysts (SBC) with large areas of calcification (7 in the femur, 4 in the humerus, and 1 each in the pelvis, the tibia and the scapula) and 402 SBC from the Hamburg Bone Tumour Registry were reviewed in a retrospective study. The analysis was done with emphasis on the clinical, radiological and histological appearances. SBC are well known lesions, but calcifying SBC (CSBC) or extensive extragnathic cement-like bone productions are rare. The clinical and radiological differential diagnosis includes fibrous dysplasia, chondroma, low-grade chondrosarcoma and osteosarcoma. Bits of this cement-like matrix are detectable within the wall of approximately 70% (278 of 402) of SBC from the registry. CSBC are changed SBC. The intraoperative confirmation of the diagnosis on a frozen section by the bone pathologist leads to curettage which is currently the most common therapy in this benign lesion.

Adolescent↗
PubMed1995

Intervertebral variation in trabecular microarchitecture throughout the normal spine in relation to age.

The vertebral bodies of the complete spine (C-3-L-5) were removed in 26 autopsy cases without evidence for primary or secondary bone disease (13 males aged 19-79 years and 13 females aged 17-90 years). A sagittal segment through the center of all vertebral bodies was embedded undecalcified in hydroxyethylmethacrylate and processed to so-called surface stained block grindings. Histomorphometric analysis of the complete segment was performed using a computer-assisted image analysis system (IBAS 2000). The structural parameters investigated were bone volume (BV/TV) and trabecular interconnection quantificated by trabecular bone pattern factor (TBPf). A close correlation of BV/TV and TBPf was found in all vertebral bodies irrespective of vertebral region (r = 0.8, p < 0.001). This indicates that the age-related decrease of trabecular bone mass is primarily the consequence of the transformation from plates to rods and the loss of whole trabecular structures. This basic principle is valid throughout the complete spine. However, the systematic analysis of vertebral trabecular bone from C-3 to L-5 revealed a significant intervertebral variation of trabecular microarchitecture. The density of trabecular structure of cervical vertebrae is much higher than that of thoracic and lumbar vertebrae (p < 0.001). The extent of age-related loss of trabecular bone mass and structure showed a decrease within the spine from the caudal to the cranial region (p < 0.05). The loss of bone volume in individuals between the ages of 30 and 80 years in the lumbar spine was 53%, whereas in the thoracic spine the decrease was 41%, and in the cervical spine only 24%.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗