Modic (endplate) changes in the lumbar spine: bone micro-architecture and remodelling.

Purpose: In the literature, inter-vertebral MRI signal intensity changes (Modic changes) were associated with corresponding histological observations on endplate biopsies. However, tissue-level studies were limited. No quantitative histomorphometric study on bone biopsies has yet been conducted for Modic changes.

Subregional DXA-derived vertebral bone mineral measures are stronger predictors of failure load in specimens with lower areal bone mineral density, compared to those with higher areal bone mineral density.

Measurement of areal bone mineral density (aBMD) in intravertebral subregions may increase the diagnostic sensitivity of dual-energy X-ray absorptiometry (DXA)-derived parameters for vertebral fragility. This study investigated whether DXA-derived bone parameters in vertebral subregions were better predictors of vertebral bone strength in specimens with low aBMD, compared to those with higher aBMD. Twenty-five lumbar vertebrae (15 embalmed and 10 fresh-frozen) were scanned with posteroanterior- (PA) and lateral-projection DXA, and then mechanically tested in compression to ultimate failure.

EphB4 enhances the process of endochondral ossification and inhibits remodeling during bone fracture repair.

Previous reports have identified a role for the tyrosine kinase receptor EphB4 and its ligand, ephrinB2, as potential mediators of both bone formation by osteoblasts and bone resorption by osteoclasts. In the present study, we examined the role of EphB4 during bone repair after traumatic injury. We performed femoral fractures with internal fixation in transgenic mice that overexpress EphB4 under the collagen type 1 promoter (Col1-EphB4) and investigated the bone repair process up to 12 weeks postfracture.

Osteoporotic characteristics persist in the spine of ovariectomized sheep after withdrawal of corticosteroid administration.

A validated ovine model of osteoporosis achieves severe bone loss in a relatively short period. This study investigated if osteoporotic features persist in this model after cessation of corticosteroid administration. Methods.

Temporal changes in bone composition, architecture, and strength following estrogen deficiency in osteoporosis.

Using an ovariectomized (OVX) ovine model, we provide an analysis of the timing of changes in bone following estrogen deficiency. The expression of genes known to regulate osteoclastogenesis, matrix production, and mineralization, as measured by real-time RT-PCR, was significantly increased by 12 months; and increased expression was maintained through to 31 months post-OVX compared to controls. FTIR spectroscopy confirmed that mineralized crystals were less mature than in controls 12 months post-OVX and were even less so by 31 months.

Micro-CT examination of human bone: from biopsies towards the entire organ.

Micro-CT systems are available that facilitate ex vivo examinations of human specimens as big as entire vertebrae, with spatial resolutions in the 10-micrometer range. This opens a new way for looking at entire bones in 3D. Accurate description of the internal microarchitecture of the entire organ can be obtained, at spatial resolutions previously achievable only on excised biopsies.

Failure strength of human vertebrae: prediction using bone mineral density measured by DXA and bone volume by micro-CT.

Significant relationships exist between areal bone mineral density (BMD) derived from dual energy X-ray absorptiometry (DXA) and bone strength. However, the predictive validity of BMD for osteoporotic vertebral fractures remains suboptimal. The diagnostic sensitivity of DXA in the lumbar spine may be improved by assessing BMD from lateral-projection scans, as these might better approximate the objective of measuring the trabecular-rich bone in the vertebral body, compared to the commonly-used posterior-anterior (PA) projections.

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 osteoarthritis.

Introduction: 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).

The different contributions of cortical and trabecular bone to implant anchorage in a human vertebra.

The quality of the peri-implant bone and the strength of the bone-implant interface are important factors for implant anchorage. With regard to peri-implant bone, cortical and trabecular compartments both contribute to the load transfer from the implant to the surrounding bone but their relative roles have yet to be investigated in detail. However, this knowledge is crucial for the better understanding of implant failure and for the development of new implants.

Measurement of subregional vertebral bone mineral density in vitro using lateral projection dual-energy X-ray absorptiometry: validation with peripheral quantitative computed tomography.

Although a strong relationship exists between areal bone mineral density (aBMD) derived from dual-energy X-ray absorptiometry (DXA) and bone strength, the predictive validity of aBMD for osteoporotic vertebral fractures remains suboptimal. The diagnostic sensitivity of DXA may be improved by assessing aBMD within vertebral subregions, rather than relying on an estimate derived from the total area of the vertebra. The objective of this study was to validate a method of measuring subregional vertebral aBMD in vitro using lateral-projection DXA against subregional volumetric BMD (vBMD) measured with peripheral quantitative computed tomography (pQCT).

Model-Independent 3D Descriptors of Vertebral Cancellous Bone Architecture.

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.

Novel assessment of subregional bone mineral density using DXA and pQCT and subregional microarchitecture using micro-CT in whole human vertebrae: applications, methods, and correspondence between technologies.

In the clinical environment dual-energy X-ray absorptiometry (DXA) is the current tool of first choice for assessing and monitoring skeletal integrity. A major drawback of standard DXA is that the bone mineral density (BMD) data cannot be used with certainty to predict who will sustain a vertebral fracture. However, measurement of BMD within vertebral subregions, instead of relying on a gross estimate of vertebral BMD, may improve diagnostic sensitivity.

Whole bone geometry and bone quality in distal forearm fracture.

Fracture of the distal radius is a sentinel for future increased risk of other "osteoporotic" fractures, in which the peak age for incidence of distal radius fracture is 5 to 10 years before that for spine and hip fractures. Mean bone mineral density (BMD) of the distal radius was lower in patients with osteoporosis compared with age- and sex-matched normal subjects. However, it has been shown that to predict the strength of the distal radius at the site where fractures occur requires more than measurement of bone mineral content (BMC) or BMD.

The use of MAPLT and MLVA analyses of phenotypically closely related isolates of Salmonella enterica serovar Typhimurium.

The resolving power of multiple-locus variable-number tandem repeat analysis (MLVA) was undertaken on 78 phenotypically closely related isolates of Salmonella enterica serovar Typhimurium that were previously analysed with multiple amplification of phage locus typing (MAPLT) and pulsed-field gel electrophoresis (PFGE). Isolates were tested with 10 primer sets targeting tandem repeat loci in the S. Typhimurium genome.

Antero-postero differences in cortical thickness and cortical porosity of T12 to L5 vertebral bodies.

Objective: This study will investigate interrelationships between the cortical shell and cancellous bone trabecular thickness, in vertebral bodies.

Methods: One hundred and sixty vertebral bodies from T12 to L5 were obtained at autopsy. The average age of the cohort was 59.

Trabecular rod buckling index in thoraco-lumbar vertebral bonedagger.

The need for improved mechanistic understanding of cancellous bone failure is at the core of important clinical problems such as osteoporosis, as well as basic biological issues such as bone formation and adaptation. Three-dimensional (3D) anaglyphs were produced from 15 T12 and L1 vertebral bodies, which encompass the adult life span in both sexes. The anaglyphs were viewed with red-green stereo glasses, using an image analyzer, and trabecular thickness and trabecular length were measured.

Effectiveness of AutoPap system location-guided screening in the evaluation of cervical cytology smears.

Location-guided screening is a feature of the AutoPap primary screening software. Areas of the smear most likely to contain an abnormality are identified for prompt review by the cytotechnologist, thereby facilitating diagnostic accuracy and reducing laboratory workload. A two-armed retrospective study comprising 6,000 conventional smears was undertaken to compare this approach with the current practice of full manual screening of conventional smears.

Interrelationships between structural parameters of cancellous bone reveal accelerated structural change at low bone volume.

Unlabelled: This study shows that change to cancellous bone structure is bone volume-dependent in a nonlinear manner. At low bone volume (< 15%), trabecular thickness and trabecular separation change at a much greater rate than at higher bone volume. This suggests that the structural integrity of the cancellous bone may become rapidly compromised when bone volume falls below a critical value.

Trabecular rod thickness by direct measurement from 3D SEM anaglyphs.

This study presents a methodology for measuring the thickness of trabecular rods directly from anaglyphs. Macerated sagittal slices of T12 vertebral bodies from 15 subjects were examined by scanning electron microscopy (SEM). Two digital images (the second image tilted 5 degrees ) were recorded, and a 3D anaglyph was created.