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Sharmila Majumdar – 1st expert on this subject based on the ideXlab platform
current diagnostic techniques in the evaluation of Bone ArchitectureCurrent Osteoporosis Reports, 2004Co-Authors: Thomas M Link, Sharmila MajumdarAbstract:
Bone quality, which encompasses trabecular Bone and cortical Bone Architecture, Bone mineralization, turnover, and microdamage, is an essential component of Bone strength. Therefore, Bone quality, Bone density, and total content are the most important parameters in the diagnosis of osteoporosis. Noninvasive assessment of Bone quality has recently received considerable attention because Bone density alone is not a surrogate for fracture prevalence and occurrence, and does not completely explain the therapeutic efficacy of emerging treatments. This paper will focus on the noninvasive assessment of trabecular Bone Architecture, one of the factors that governs Bone strength and may be categorized as a contributor to Bone quality. The methodologies described will include magnetic resonance imaging, clinical multislice spiral computed tomography, and micro-computed tomography, along with computerized analysis of radiographic patterns of trabecular Bone.
Current technologies in the evaluation of Bone ArchitectureCurrent Osteoporosis Reports, 2003Co-Authors: Sharmila MajumdarAbstract:
In the context of osteoporosis, Bone quality (which encompasses trabecular Bone and cortical Bone Architecture), Bone mineralization, turnover, and microdamage are all important, as are Bone density and total content. Noninvasive assessment of Bone quality has recently received considerable attention because Bone density alone is not a surrogate for fracture prevalence and occurrence, and does not completely explain the therapeutic efficacy of emerging treatments. This paper focuses on the assessment of trabecular Bone Architecture, one of the factors that governs Bone strength and may be categorized as a contributor to Bone quality. The methodologies described include micro-computed tomography, magnetic resonance imaging, and computerized analysis of radiographic patterns of trabecular Bone.
direct measures of trabecular Bone Architecture from mr imagesAdvances in Experimental Medicine and Biology, 2001Co-Authors: Andres Laib, David C. Newitt, O Beuf, Ahi Sema Issever, Sharmila MajumdarAbstract:
Osteoporosis is a Bone disorder involving a decrease in Bone mass and changes in the cancellous Bone network leading to an increase in fracture risk. Until recently only Bone mass and density were routinely assessed in patients, usually measured by dual-energy X-ray absorptiometry (DXA) or by quantitative computed tomography (QCT). Although Bone mineral density (BMD) is an important determinant of Bone strength, there is strong evidence that Architecture of cancellous Bone plays a significant role in Bone strength and determines its biomechanical properties.1The importance of three-dimensional trabecular Bone structure in osteoporosis increases when evaluating the response to therapy, as studies have reported that changes in fracture risk were not mainly attributable to BMD.2The measurement of both Bone micro-Architecture and BMD may improve the estimation of Bone strength. However, the precise relationship between density, structure and mechanical properties is still under investigation.
Ian H. Parkinson – 2nd expert on this subject based on the ideXlab platform
application of in vivo micro computed tomography in the temporal characterisation of subchondral Bone Architecture in a rat model of low dose monosodium iodoacetate induced osteoarthritisArthritis Research & Therapy, 2011Co-Authors: Ian H. Parkinson, Geetha Mohan, Egon Perilli, J S Kuliwaba, Julia M HumphriesAbstract:
Osteoarthritis (OA) is a complex, multifactorial joint disease affecting both the cartilage and the subchondral Bone. Animal models of OA aid in the understanding of the pathogenesis of OA and testing suitable drugs for OA treatment. In this study we characterized the temporal changes in the tibial subchondral Bone Architecture in a rat model of low-dose monosodium iodoacetate (MIA)-induced OA using in vivo micro-computed tomography (CT).
Model-Independent 3D Descriptors of Vertebral Cancellous Bone Architecture.Journal of Osteoporosis, 2009Co-Authors: Ian H. Parkinson, Danielle Forbes, Peter Sutton-smith, Nicola L. FazzalariAbstract:
High-resolution micro computed tomography has enabled measurement of Bone Architecture derived from 3D representations of cancellous Bone. Twenty-eight vertebral bodies were obtained from four embalmed male cadavers. From 3D anaglyphs, trabecular rod thickness and length were measured and the trabecular rod Buckling index was calculated. From 3D voxel-based datasets, Bone volume density, trabecular thickness, and trabecular separation were measured. Also, trabecular Bone pattern factor, structural model index, connectivity density, and degree of anisotropy were calculated. Bone volume density alone explains 59% of the variability in trabecular rod Buckling index. The addition of connectivity density, trabecular separation, and structural model index, in a multiple regression statistical model, improves the explanatory power to 77%. The relationships between measures of cancellous Bone Architecture and a derived measure of trabecular rod strength were investigated. Morphological descriptors of cancellous Bone provide a composite explanatory model of trabecular rod strength.
intervertebral disc disorganization is related to trabecular Bone Architecture in the lumbar spineJournal of Bone and Mineral Research, 2001Co-Authors: E K Simpson, Ian H. Parkinson, B.a. Manthey, Nicola L. FazzalariAbstract:
Cancellous Bone morphometry was investigated in the sagittal plane of lumbar vertebrae using histoquantitation. The aim of this study was to identify variations in cancellous Bone Architecture at increasing states of intervertebral disc (IVD) disorganization after age adjustment and to investigate regional variations within the whole vertebral body. Measurements were taken of the ratio of Bone volume (BV) to total volume (TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and trabecular number (Tb.N). Lumbar spines (T12-L5) of 19 men and 8 women were removed at autopsy from an adult sample with no clinical history of Bone-related disease or histologically identifiable Bone disease. It was found that degeneration of the IVD becomes more common with increasing age. After age-adjustment, significant increases in the proportion of BV/TV were observed in the presence of advancing IVD disorganization. Significant architectural changes were observed in the anterior regions of the vertebral body with increases in Tb.Th and Tb.N and decreases in Tb.Sp. Minimal alterations were found at posterior regions. Bone loss was observed in central regions (most distant from the cortex) as IVD disorganization increased through reduction in both Tb.N and Tb.Th. The BV/TV increase in anterior areas of the centrum may be a response to a redistribution of load to the vertebral body periphery as a result of IVD disorganization. It appears that trabecular morphology is related to the condition of the associated IVD, rather than being the sole consequence of a loss of BV/TV with age. This relationship could influence the occurrence of vertebral body crush fracture.
Nancy E. Lane – 3rd expert on this subject based on the ideXlab platform
role of Bone Architecture and anatomy in osteoarthritisBone, 2012Co-Authors: Julie C Bakerlepain, Nancy E. LaneAbstract:
Abstract When considering the pathogenesis of osteoarthritis (OA), it is important to review the contribution of Bone in addition to the contribution of cartilage and synovium. Although Bone clearly plays a role in determining the distribution of biomechanical forces across joints, which in turn plays a role in the initiation of OA, it has also more recently been appreciated that Bone may contribute in a biological sense to the pathogenesis of OA. Far from being a static structure, Bone is a dynamic tissue undergoing constant remodeling, and it is clear from a number of radiographic and biochemical studies that Bone and cartilage degradation occurs hand in hand. Whether the initial instigating event in OA occurs in cartilage or Bone is not known, but it is clear that bony changes occur very early in the pathogenesis of OA and often predate radiographic appearance of the disease. This review focuses on the structural variants of both hip and knee that have been associated with OA and the ultrastructural Bone changes in these sites occurring in early OA pathogenesis. This article is part of a Special Issue entitled “Osteoarthritis”.
both hpth 1 34 and bfgf increase trabecular Bone mass in osteopenic rats but they have different effects on trabecular Bone ArchitectureJournal of Bone and Mineral Research, 2003Co-Authors: Nancy E. Lane, J H Kinney, Gunnard Modin, M Balooch, T J WronskiAbstract:
Osteoporosis is a syndrome of excessive skeletal fragility that results from both the loss of trabecular Bone mass and trabecular Bone connectivity. Recently, bFGF has been found to increase trabecular Bone mass in osteoporotic rats. The purpose of this study was to compare how trabecular Bone Architecture, Bone cell activity, and strength are altered by two different Bone anabolic agents, bFGF and hPTH(1–34), in an osteopenic rat model.
Materials and Methods: Six-month-old female Sprague-Dawley rats (n = 74) were ovariectomized (OVX) or sham-operated (sham) and maintained untreated for 2 months. Then OVX rats were subcutaneously injected with basic fibroblast factor (bFGF; 1 mg/kg, 5 days/week), human parathyroid hormone [hPTH(1–34); 40 μg/kg, 5 days/week], or vehicle for 60 days (days 60–120 ). Sham-operated and one group of OVX animals were injected with vehicle. Biochemical markers of Bone turnover (urinary deoxypyridinoline cross-links; Quidel Corp., San Diego, CA, USA) and serum osteocalcin (Biomedical Technologies, Stroughton, MA, USA) were obtained at study days 0, 60, 90, and 120 and analyzed by ELISA. At death, the right proximal tibial metaphysis was removed, and microcomputed tomography was performed for trabecular Bone structure and processed for histomorphometry to assess Bone cell activity. The left proximal tibia was used for nanoindentation/mechanical testing of individual trabeculae. The data were analyzed with Kruskal Wallis and post hoc testing as needed.
Results: Ovariectomy at day 60 resulted in about a 50% loss of trabecular Bone volume compared with sham-treated animals. By day 120 post-OVX, OVX + vehicle treated animals had decreased trabecular Bone volume, connectivity, number, and high Bone turnover compared with sham-operated animals [p < 0.05 from sham-, hPTH(1–34)-, and bFGF-treated groups]. Treatment of OVX animals with bFGF and hPTH(1–34) both increased trabecular Bone mass, but hPTH(1–34) increased trabecular thickness and bFGF increased trabecular number and connectivity. Histomorphometry revealed increased mineralizing surface and Bone formation rate in both bFGF and hPTH(1–34) animals. However, osteoid volume was greater in bFGF-treated animals compared with both the hPTH(1–34) and OVX + vehicle animals (p < 0.05). Nanoindentation by atomic force microscope was performed on approximately 20 individual trabeculae per animal (three animals per group) and demonstrated that elastic modulus and hardness of the trabeculae in bFGF-treated animals were similar to that of the hPTH-treated and sham + vehicle-treated animals. Conclusion: Both hPTH(1–34) and bFGF are anabolic agents in the osteopenic female rat. However, hPTH(1–34) increases trabecular Bone volume primarily by thickening existing trabeculae, whereas bFGF adds trabecular Bone mass through increasing trabecular number and trabecular connectivity. These results suggest the possibility of sequential treatment paradigms for severe osteoporosis.
Trabecular Bone Architecture in the distal radius using magnetic resonance imaging in subjects with fractures of the proximal femurOsteoporosis International, 1999Co-Authors: Sharmila Majumdar, Thomas M Link, Peter Augat, David C. Newitt, Nancy E. Lane, Harry K. GenantAbstract:
To determine whether magnetic resonance (MR)-derived measures of trabecular Bone Architecture in the distal radius are predictive for prevalent hip fractures, 20 subjects with hip fractures and 19 age-matched postmenopausal controls were studied. Bone mineral density (BMD) measures at the hip (dual-energy X-ray absorptiometry, DXA) and the distal radius (peripheral quantitative computed tomography, pQCT) were also obtained. We compared the MR-based structural measures derived in the radius with those in the calcaneus of the same patients. In the radius, images were acquired at an in-plane resolution of 156 μm and a slice thickness of 0.5 mm. Stereologic measures such as the apparent trabecular thickness (app. Tb.Th), fractional trabecular Bone volume (app. BV/TV), trabecular spacing (app. Tb.Sp) and trabecular number (app. Tb.N) were derived from the images. Measures of app. Tb.Sp and app. Tb.N in the distal radius showed significant (p