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Epperson RT, Williams DL, Rogers B, Maxwell J, Stevens P. Assessing the safety of an epiphyseal plate biopsy in a translational lamb model. J Orthop Res 2021; 39:2653-2662. [PMID: 33580528 DOI: 10.1002/jor.25004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/10/2020] [Accepted: 02/10/2021] [Indexed: 02/04/2023]
Abstract
The literature demonstrates that obtaining a biopsy of the physis may be beneficial for diagnostic purposes. A small biopsy of the epiphyseal plate may allow for earlier detection of certain conditions and be used to monitor the healing of diseased and/or damaged physes. However, due to the fear of a growth arrest in a growing child, biopsies are not currently performed. In this study, we investigated the effects of a biopsy of the epiphyseal plate in 3-month-old lambs. A total of 4.2 mm biopsy samples were captured in the proximal tibiae and distal femora physes. The lambs were monitored 12- and 24-week post-biopsy. Computed tomography (CT) and micro-CT scans were obtained to determine if any angular deformities occurred, while scanning electron microscope (SEM) and histological analysis were utilized to assess the bone response due to the biopsy. The contralateral limbs served as unaltered controls for direct comparison within each lamb. The data demonstrated no signs of angular deformities following a 4.2 mm biopsy of the physis. Bone growth/elongation was confirmed by CT, SEM, and fluorochrome analyses and indicated that the lambs were in fact immature and still growing at the time of the biopsy. Clinical Significance: This investigation demonstrated that a small biopsy of the epiphyseal plate can be obtained safely without the cause of growth arrest and angular deformities. The ability to precisely diagnose, treat, and/or monitor at-risk children at an earlier timepoint by way of a biopsy sample could be an important advancement in regard to researching diseased and/or damaged physes.
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Affiliation(s)
- Richard T Epperson
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA.,Department of Veterans Affairs, Bone and Joint Research Laboratory, Salt Lake City, Utah, USA
| | - Dustin L Williams
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA.,Department of Veterans Affairs, Bone and Joint Research Laboratory, Salt Lake City, Utah, USA.,Department of Pathology, University of Utah, Salt Lake City, Utah, USA.,Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA.,Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Brady Rogers
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA.,Department of Veterans Affairs, Bone and Joint Research Laboratory, Salt Lake City, Utah, USA
| | - John Maxwell
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA.,Department of Veterans Affairs, Bone and Joint Research Laboratory, Salt Lake City, Utah, USA
| | - Peter Stevens
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA.,Primary Children's Hospital, Salt Lake City, Utah, USA
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2
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Histocompositional organization and toughening mechanisms in antler. J Struct Biol 2014; 187:129-148. [DOI: 10.1016/j.jsb.2014.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 06/04/2014] [Accepted: 06/13/2014] [Indexed: 12/16/2022]
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3
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Guda T, Labella C, Chan R, Hale R. Quality of bone healing: Perspectives and assessment techniques. Wound Repair Regen 2014; 22 Suppl 1:39-49. [DOI: 10.1111/wrr.12167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 01/28/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Teja Guda
- Dental Trauma Research Detachment; US Army Institute of Surgical Research; Fort Sam Houston
- Wake Forest Institute for Regenerative Medicine; Winston-Salem North Carolina
- Biomedical Engineering; University of Texas at San Antonio; San Antonio Texas
| | - Carl Labella
- Dental Trauma Research Detachment; US Army Institute of Surgical Research; Fort Sam Houston
| | - Rodney Chan
- Dental Trauma Research Detachment; US Army Institute of Surgical Research; Fort Sam Houston
| | - Robert Hale
- Dental Trauma Research Detachment; US Army Institute of Surgical Research; Fort Sam Houston
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4
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Brennan MA, Gleeson JP, O'Brien FJ, McNamara LM. Effects of ageing, prolonged estrogen deficiency and zoledronate on bone tissue mineral distribution. J Mech Behav Biomed Mater 2013; 29:161-70. [PMID: 24090875 DOI: 10.1016/j.jmbbm.2013.08.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 08/27/2013] [Accepted: 08/31/2013] [Indexed: 02/03/2023]
Abstract
The quantity and distribution of bone tissue mineral are key determinants of bone strength. Recent research revealed altered mineral distribution within sheep femora following estrogen deficiency. Rapid increases in bone remodeling occur at the onset of estrogen deficiency and abate over time. Therefore, altered tissue mineralization might be a transient characteristic of osteoporosis. Bisphosphonates reduce fracture incidence by 40-60% but increases in bone mineral density are insufficient to explain such changes. In this study the hypotheses that bone tissue mineralization is altered over prolonged estrogen depletion and bisphosphonate treatment were tested. Quantitative backscattered imaging (qBEI) was used to quantify bone mineral density distribution (BMDD) parameters (mean, FWHM) in trabeculae from the proximal femora of an ovariectomized sheep model that underwent estrogen deficiency for 31 months, an ovariectomized group administered with Zoledronic acid and age-matched controls. To assess the effects of normal ageing and prolonged estrogen deficiency, data were compared to BMDD data from sheep that were estrogen deficient for 12 months and age-matched controls. This study reports that normal ageing increases mean mineralization and mineral heterogeneity at a trabecular level. In contrast, prolonged estrogen deficiency leads to significantly decreased mean mineralization and further exacerbates increases in mineral heterogeneity. Interestingly, ZOL treatment of OVX sheep significantly reduced tissue mineral variability, both at a trabecular level and between femoral regions. Together, these findings indicate that ZOL treatment acts to reverse the increased mineral heterogeneity occurring during estrogen deficiency, which may contribute to its capacity to reduce osteoporotic fractures.
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Affiliation(s)
- M A Brennan
- Biomechanics Research Centre (BMEC), Department of Mechanical and Biomedical Engineering, National University of Ireland, Galway, Ireland; Bioengineering Sciences Research Group, Faculty of Engineering and the Environment, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
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5
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Vos M, Tökési K, Benkö I. The potential of materials analysis by electron rutherford backscattering as illustrated by a case study of mouse bones and related compounds. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:576-586. [PMID: 23642665 DOI: 10.1017/s143192761300041x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Electron Rutherford backscattering (ERBS) is a new technique that could be developed into a tool for materials analysis. Here we try to establish a methodology for the use of ERBS for materials analysis of more complex samples using bone minerals as a test case. For this purpose, we also studied several reference samples containing Ca: calcium carbonate (CaCO(3)) and hydroxyapatite and mouse bone powder. A very good understanding of the spectra of CaCO(3) and hydroxyapatite was obtained. Quantitative interpretation of the bone spectrum is more challenging. A good fit of these spectra is only obtained with the same peak widths as used for the hydroxyapatite sample, if one allows for the presence of impurity atoms with a mass close to that of Na and Mg. Our conclusion is that a meaningful interpretation of spectra of more complex samples in terms of composition is indeed possible, but only if widths of the peaks contributing to the spectra are known. Knowledge of the peak widths can either be developed by the study of reference samples (as was done here) or potentially be derived from theory.
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Affiliation(s)
- Maarten Vos
- Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200, Australia.
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6
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Kourkoumelis N, Balatsoukas I, Tzaphlidou M. Ca/P concentration ratio at different sites of normal and osteoporotic rabbit bones evaluated by Auger and energy dispersive X-ray spectroscopy. J Biol Phys 2011; 38:279-91. [PMID: 23449289 DOI: 10.1007/s10867-011-9247-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 10/25/2011] [Indexed: 11/24/2022] Open
Abstract
Osteoporosis is a systemic skeletal disorder associated with reduced bone mineral density and the consequent high risk of bone fractures. Current practice relates osteoporosis largely with absolute mass loss. The assessment of variations in chemical composition in terms of the main elements comprising the bone mineral and its effect on the bone's quality is usually neglected. In this study, we evaluate the ratio of the main elements of bone mineral, calcium (Ca), and phosphorus (P), as a suitable in vitro biomarker for induced osteoporosis. The Ca/P concentration ratio was measured at different sites of normal and osteoporotic rabbit bones using two spectroscopic techniques: Auger electron spectroscopy (AES) and energy-dispersive X-ray spectroscopy (EDX). Results showed that there is no significant difference between samples from different genders or among cortical bone sites. On the contrary, we found that the Ca/P ratio of trabecular bone sections is comparable to cortical sections with induced osteoporosis. Ca/P ratio values are positively related to induced bone loss; furthermore, a different degree of correlation between Ca and P in cortical and trabecular bone is evident. This study also discusses the applicability of AES and EDX to the semiquantitative measurements of bone mineral's main elements along with the critical experimental parameters.
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Affiliation(s)
- Nikolaos Kourkoumelis
- Department of Medical Physics, Medical School, University of Ioannina, Ioannina, 45110 Greece
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7
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Liu Y, Mai S, Li N, Yiu CKY, Mao J, Pashley DH, Tay FR. Differences between top-down and bottom-up approaches in mineralizing thick, partially demineralized collagen scaffolds. Acta Biomater 2011; 7:1742-51. [PMID: 21111071 DOI: 10.1016/j.actbio.2010.11.028] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 11/18/2010] [Accepted: 11/19/2010] [Indexed: 11/15/2022]
Abstract
Biominerals exhibit complex hierarchical structures derived from bottom-up self-assembly mechanisms. Type I collagen serves as the building block for mineralized tissues such as bone and dentin. In the present study, 250-300 μm thick, partially demineralized collagen scaffolds exhibiting a gradient of demineralization from the base to surface were mineralized using a classical top-down approach and a non-classical bottom-up approach. The top-down approach involved epitaxial growth over seed crystallites. The bottom-up approach utilized biomimetic analogs of matrix proteins to stabilize amorphous calcium phosphate nanoprecursors and template apatite nucleation and growth within the collagen matrix. Micro-computed tomography and transmission electron microscopy were employed to examine mineral uptake and apatite arrangement within the mineralized collagen matrix. The top-down approach could mineralize only the base of the partially demineralized scaffold, where remnant seed crystallites were abundant. Minimal mineralization was observed along the surface of the scaffold; extrafibrillar mineralization was predominantly observed. Conversely, the entire partially demineralized scaffold, including apatite-depleted collagen fibrils, was mineralized by the bottom-up approach, with evidence of both intrafibrillar and extrafibrillar mineralization. Understanding the different mechanisms involved in these two mineralization approaches is pivotal in adopting the optimum strategy for fabricating novel nanostructured materials in bioengineering research.
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Affiliation(s)
- Yan Liu
- Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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8
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Sinclair KD, Curtis BD, Koller KE, Bloebaum RD. Characterization of the Anchoring Morphology and Mineral Content of the Anterior Cruciate and Medial Collateral Ligaments of the Knee. Anat Rec (Hoboken) 2011; 294:831-8. [DOI: 10.1002/ar.21374] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 12/21/2010] [Accepted: 02/03/2011] [Indexed: 11/08/2022]
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9
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Skedros JG, Kiser CJ, Keenan KE, Thomas SC. Analysis of osteon morphotype scoring schemes for interpreting load history: evaluation in the chimpanzee femur. J Anat 2011; 218:480-99. [PMID: 21323667 DOI: 10.1111/j.1469-7580.2011.01348.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Osteon morphotype scores (MTSs) allow for quantification of mechanically important collagen/lamellar variations between secondary osteons when viewed in circularly polarized ight (CPL). We recently modified the 6-point MTS method of Martin et al. (Martin RB, Gibson VA, Stover SM, Gibeling JC, Griffin LV (1996a) Osteonal structure in the equine third metacarpus. Bone 19, 165-71) and reported superiority of this modified method in correlating with 'tension' and 'compression' cortices of both chimpanzee proximal femoral diaphyses and diaphyses of other non-anthropoid bones that are loaded in habitual bending (Skedros et al. 2009, 2011). In these studies, the 'tension' and 'compression' cortices differed significantly in predominant collagen fiber orientation (CFO) based on weighted-mean gray levels (CFO/WMGLs) in CPL images. In chimpanzee femora, however, some osteons were difficult to score with the 6-point method; namely, 'hybrids' with peripherally bright 'hoops' and variability in alternating rings within the osteon wall. We hypothesized that some of these hybrids would be more prevalent in regions subject to torsion than bending. In this perspective the present study was aimed at expanding our 6-point scoring method (S-6-MTS) into two 12-point methods with six additional morphotypes that considered these hybrids. Three- and 4-point methods were also evaluated. We hypothesized that at least one of these other methods would out-perform the S-6-MTS in terms of accuracy, reliability, and interpreting torsion vs. bending load histories. Osteon morphotypes were quantified in CPL images from transverse sections of eight adult chimpanzee femora (neck, proximal diaphysis, mid-diaphysis), where the mid-diaphysis and base- and mid-neck locations have relatively more complex loading (e.g. torsion + bending) than the proximal diaphysis, where bending predominates. Correlation coefficients between CFO/WMGL and MTSs showed that the S-6-MTS method was either stronger or equivalent to the 12-point methods, and typically stronger than the 3- and 4-point methods for all load environments. In nearly all instances the S-6-MTS is more reliable and accurate when it is applied to cases where interpreting load history requires distinguishing habitual bending from torsion. Consequently, in studies of osteonal adaptations for these load histories the 3- and 4-point methods are not stronger correlates, and the extra time required to assign additional scores in the 12-point methods is both unnecessary and can be highly unreliable.
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Affiliation(s)
- John G Skedros
- Bone and Joint Research Laboratory, Department of Veterans Affairs Medical Center, The University of Utah, Salt Lake City, UT, USA.
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10
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Wood MA, Yang Y, Baas E, Meredith DO, Richards RG, Kuiper JH, El Haj AJ. Correlating cell morphology and osteoid mineralization relative to strain profile for bone tissue engineering applications. J R Soc Interface 2008; 5:899-907. [PMID: 18077245 PMCID: PMC2607462 DOI: 10.1098/rsif.2007.1265] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A number of bone tissue engineering strategies use porous three-dimensional scaffolds in combination with bioreactor regimes. The ability to understand cell behaviour relative to strain profile will allow for the effects of mechanical conditioning in bone tissue engineering to be realized and optimized. We have designed a model system to investigate the effects of strain profile on bone cell behaviour. This simplified model has been designed with a view to providing insight into the types of strain distribution occurring across a single pore of a scaffold subjected to perfusion-compression conditioning. Local strains were calculated at the surface of the pore model using finite-element analysis. Scanning electron microscopy was used in secondary electron mode to identify cell morphology within the pore relative to local strains, while backscattered electron detection in combination with X-ray microanalysis was used to identify calcium deposition. Morphology was altered according to the level of strain experienced by bone cells, where cells subjected to compressive strains (up to 0.61%) appeared extremely rounded while those experiencing zero and tensile strain (up to 0.81%) were well spread. Osteoid mineralization was similarly shown to be dose dependent with respect to substrate strain within the pore model, with the highest level of calcium deposition identified in the intermediate zones of tension/compression.
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Affiliation(s)
- M A Wood
- Institute of Science and Technology in Medicine, Keele University, Thornburrow Drive, Hartshill, Staffordshire ST4 7QB, UK.
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11
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Traini T, Degidi M, Murmura G, Piattelli A, Caputi S. Bone microstructure evaluation near unloaded dental implants combining confocal scanning laser microscopy, circularly polarized light microscopy, and SEM backscattered electrons imaging. Int J Immunopathol Pharmacol 2008; 20:37-41. [PMID: 17897500 DOI: 10.1177/039463200702001s09] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The aim of this report is to present a new investigative approach to implant dentistry based on the correlation of qualitative and quantitative data reported on the same figure by overlapping different images collected on the specimen with different investigative systems. Six unloaded titanium dental implants retrieved with peri-implant bone from the mandible of 2 patients after a 6 month period were used in this study. Samples of the peri-implant tissues embedded in resin were imaged by scanning electron microscopy using backscattered electrons signal (SEM BSE), confocal scanning laser microscopy (CSLM) and circularly polarized light microscopy (CPLM). The SEM BSE images were used to identify the different levels of mineral density. The CSLM images provided all the information on cells and bone marrow spaces. The CPLM images gave the collagen fibre orientation. To overlap the images we used a program introduced by Alan Boyde, based on a linear transformation matrix which projects one system onto the other. The total bone area investigated was of 695x10(3) pixels. The low mineral density index was 40.1, with an extension area of 344x10(3) +/- 23x10(3) pixels (mean +/- SD) while the high mineral density index was 54.8 with an extension area of 317x10(3) +/- 22x10(3) pixels (mean +/- SD). Transverse collagen fibers showed an extension area of 201x10(3) +/- 25x10(2) pixels (mean +/- SD) (28.9%), while the area for longitudinal orientation was 282x10(3) +/- 19x10(2) pixels (mean +/- SD) (40.6%). The marrow spaces showed an extension of 113x10(3) +/- 24x10(2) pixels (mean +/- SD) (16.3%). This method demonstrated that bone near unloaded implants showed almost the same extension for longitudinal and transverse collagen fibre with a predominantly low mineral density index closest to the implant surface.
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Affiliation(s)
- T Traini
- Department of Stomatology and Oral Sciences, School of Dentistry, University of Chieti, Italy.
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12
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Bloebaum RD, Holmes JL, Skedros JG. Mineral content changes in bone associated with damage induced by the electron beam. SCANNING 2005; 27:240-8. [PMID: 16268176 DOI: 10.1002/sca.4950270504] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Energy-dispersive x-ray (EDX) spectroscopy and backscattered electron (BSE) imaging are finding increased use for determining mineral content in microscopic regions of bone. Electron beam bombardment, however, can damage the tissue, leading to erroneous interpretations of mineral content. We performed elemental (EDX) and mineral content (BSE) analyses on bone tissue in order to quantify observable deleterious effects in the context of (1) prolonged scanning time, (2) scan versus point (spot) mode, (3) low versus high magnification, and (4) embedding in poly-methylmethacrylate (PMMA). Undemineralized cortical bone specimens from adult human femora were examined in three groups: 200x embedded, 200x unembedded, and 1000x embedded. Coupled BSE/EDX analyses were conducted five consecutive times, with no location analyzed more than five times. Variation in the relative proportions of calcium (Ca), phosphorous (P), and carbon (C) were measured using EDX spectroscopy, and mineral content variations were inferred from changes in mean gray levels ("atomic number contrast") in BSE images captured at 20 keV. In point mode at 200x, the embedded specimens exhibited a significant increase in Ca by the second measurement (7.2%, p < 0.05); in scan mode, a small and statistically nonsignificant increase (1.0%) was seen by the second measurement. Changes in P were similar, although the increases were less. The apparent increases in Ca and P likely result from decreases in C: -3.2% (p < 0.05) in point mode and -0.3% in scan mode by the second measurement. Analysis of unembedded specimens showed similar results. In contrast to embedded specimens at 200x, 1000x data showed significantly larger variations in the proportions of Ca, P, and C by the second or third measurement in scan and point mode. At both magnifications, BSE image gray level values increased (suggesting increased mineral content) by the second measurement, with increases up to 23% in point mode. These results show that mineral content measurements can be reliable when using coupled BSE/EDX analyses in PMMA-embedded bone if lower magnifications are used in scan mode and if prolonged exposure to the electron beam is avoided. When point mode is used to analyze minute regions, adjustments in accelerating voltages and probe current may be required to minimize damage.
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Affiliation(s)
- Roy D Bloebaum
- Bone and Joint Research Laboratory, Department of Veterans Affairs Medical Center, Salt Lake City Health Care System, Salt Lake City, UT 84148-9998, USA.
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13
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Skedros JG, Holmes JL, Vajda EG, Bloebaum RD. Cement lines of secondary osteons in human bone are not mineral-deficient: New data in a historical perspective. ACTA ACUST UNITED AC 2005; 286:781-803. [PMID: 16037990 DOI: 10.1002/ar.a.20214] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Using qualitative backscattered electron (BSE) imaging and quantitative energy dispersive X-ray (EDX) spectroscopy, some investigators have concluded that cement (reversal) lines located at the periphery of secondary osteons are poorly mineralized viscous interfaces with respect to surrounding bone. This conclusion contradicts historical observations of apparent highly mineralized (or collagen-deficient) cement lines in microradiographs. Such conclusions, however, may stem from unrecognized artifacts that can occur during scanning electron microscopy. These include specimen degradation due to high-energy beams and the sampling of electron interaction volumes that extend beyond target locations during EDX analysis. This study used quantitative BSE imaging and EDX analysis, each with relatively lower-energy beams, to test the hypothesis that cement lines are poorly mineralized. Undemineralized adult human femoral diaphyses (n = 8) and radial diaphyses (n = 5) were sectioned transversely, embedded in polymethyl methacrylate, and imaged in a scanning electron microscope for BSE and EDX analyses. Unembedded samples were also evaluated. Additional thin embedded samples were stained and evaluated with light microscopy and correlated BSE imaging. BSE analyses showed the consistent presence of a bright line (higher atomic number) coincident with the classical location and description of the cement line. This may represent relative hypermineralization or, alternatively, collagen deficiency with respect to surrounding bone. EDX analyses of cement lines showed either higher Ca content or equivalent Ca content when compared to distant osteonal and interstitial bone. These data reject the hypothesis that cement lines of secondary osteons are poorly mineralized.
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Affiliation(s)
- John G Skedros
- Bone and Joint Research Laboratory, Department of Veterans Affairs Medical Center, Salt Lake City, Utah, USA.
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14
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Huja SS, Roberts W. Mechanism of osseointegration: characterization of supporting bone with indentation testing and backscattered imaging. Semin Orthod 2004. [DOI: 10.1053/j.sodo.2004.01.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Grabner B, Landis WJ, Roschger P, Rinnerthaler S, Peterlik H, Klaushofer K, Fratzl P. Age- and genotype-dependence of bone material properties in the osteogenesis imperfecta murine model (oim). Bone 2001; 29:453-7. [PMID: 11704498 DOI: 10.1016/s8756-3282(01)00594-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cortical mineralization of long bones was studied in collagen alpha2(I)-deficient mice (oim) used as a model for human osteogenesis imperfecta. Aspects of the age development of the mice were characterized by combining nanometer- to micrometer-scale structural analysis with microhardness measurements. Bone structure was determined from homozygous (oim/oim) and heterozygous (oim/+) mice and their normal (+/+) littermates as a function of animal age by small-angle X-ray scattering (SAXS) and quantitative backscattered electron imaging (qBEI) measurements. SAXS studies found anomalies in the size and arrangement of bone mineral crystals in both homozygous and heterozygous mice aged 1-14 months. Generally, the crystals were smaller in thickness and less well aligned in these mice compared with control animals. An increase in the mean crystal thickness of the bone was found within all three genotypes up to an age of 3 months. Vicker's hardness measurements were significantly enhanced for oim bone (homozygotes and heterozygotes) compared with controls. The microhardness values were correlated directly with increased mineral content of homozygous and heterozygous compared with control bone, as determined by qBEI analysis. There was also a significant increase of mineral content with age. Two possibilities for collagen-mineral association are discussed for explaining the increased hardness and mineral content of oim/oim bone, together with its decreased toughness and thinner mineral crystals. As a consequence of the present measurements, one model for oim bone could incorporate small and densely packed mineral crystals. A second model for possible collagen-mineral association in oim material would consist of two families of mineral crystals, one being smaller and the other being much larger than the crystals found in normal mouse long bones.
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Affiliation(s)
- B Grabner
- Ludwig Boltzmann Institute of Osteology, Fourth Medical Department, Hanusch Hospital and UKH Meidling, Vienna, Austria
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16
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Willie BM, Shea JE, Bloebaum RD, Hofmann AA. Elemental and morphological identification of third-body particulate and calcium stearate inclusions in polyethylene components. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 53:137-42. [PMID: 10713559 DOI: 10.1002/(sici)1097-4636(2000)53:2<137::aid-jbm2>3.0.co;2-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Third-body particulate such as human bone chips, hydroxyapatite, and bone cement are considered contributing factors in accelerated wear in total joint replacement. Particulate wear debris is now considered the major contributing factor in aseptic loosening of total joint replacements. The ability to distinguish between different third-body particulate is necessary to better understand wear mechanisms when conducting implant retrieval analysis. The objective of this investigation is to demonstrate that backscattered electron imaging with correlated energy dispersive X-ray analysis can accurately identify third-body particulate in retrieved polyethylene components. It is important that this technique can also distinguish between third-body particulate and normal inclusions in the polyethylene such as calcium stearate, based on the distinct morphology and elemental composition of each material. Therefore, the ability to distinguish third-body particulate from calcium stearate inclusions is essential in gaining a better understanding of the contributing factors associated with coating separation and accelerated wear observed in clinically retrieved polyethylene components.
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Affiliation(s)
- B M Willie
- Bone and Joint Research Laboratory (151F), VA Medical Center, 500 Foothill Blvd., Salt Lake City, UT 84148, USA
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17
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Holmes JL, Bachus KN, Bloebaum RD. Thermal effects of the electron beam and implications of surface damage in the analysis of bone tissue. SCANNING 2000; 22:243-248. [PMID: 10958391 DOI: 10.1002/sca.4950220403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Electron beam interactions with specimens in the scanning electron microscope (SEM) can lead to increased surface temperatures and damage. These changes may have significant consequences in the analysis of bone tissue. An investigation was performed to measure the surface temperature changes associated with the electron beam on a thermocouple with systematic variations in operating conditions. Probe currents, magnifications, and accelerating voltages were incrementally adjusted to measure the temperature changes and to make assessments for determining optimal operating conditions for the SEM in future analyses of bone tissue. Results from this study suggest that thermal effects were minimal at lower accelerating voltages (< 20 kV), lower probe currents (< 10 nA), and lower magnifications, but surface damage may still occur during the analysis of bone tissue.
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Affiliation(s)
- J L Holmes
- Department of Veterans Affairs, Salt Lake City Health Care System, Utah 84148, USA
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