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Micron (Oxford, England : 1993) 2005Osteoinduction is a property not traditionally attributed to Calcium Phosphate ceramics. Histologic, SEM and X-ray microanalyses of a biopsy of pulmonary alveolar... (Review)
Review
Osteoinduction is a property not traditionally attributed to Calcium Phosphate ceramics. Histologic, SEM and X-ray microanalyses of a biopsy of pulmonary alveolar microlithiasis allow to discredit this opinion. Bone, even lamellar type, was ectopically formed on microliths undergoing osteoclastic erosion. The SEM and X-ray microanalyses of coral granules implanted in humans indicate an osteoconductive property for both Calcium and Phosphorus. Analysis of in vitro allows to propose an enhancement of the osteocapability of coral. Lamellar bone formation in the near absence of loads undermines the opinion which sees a correlation between lamellar bone and mechanical loads. Analysis of the bone surrounding an uncemented titanium hip prosthesis highlights that both remodeled and newly formed bone have lamellae oriented parallel to prosthesis surfaces, i.e. orthogonal to loads, as opposed to that of lamellar bone of osteons which are oriented parallel to loads. Analysis of longitudinal sections of cortical bone under polarized light points out that lamellae are displaced parallel to the cement line surface both in the conic end of osteons and in Volkman's canals with thick wall, i.e. undergoing sloped load directions. In conclusion, there may be a relationship between lamellae formation and gravity.
Topics: Animals; Biocompatible Materials; Biomechanical Phenomena; Bone Remodeling; Bone and Bones; Calcium; Electron Probe Microanalysis; Female; Gravitation; Haversian System; Hip Prosthesis; Humans; Microscopy, Electron, Scanning; Osteoclasts; Osteogenesis; Phosphorus
PubMed: 16169740
DOI: 10.1016/j.micron.2005.05.008 -
Journal of Biomechanics Apr 1995A model is developed whereby the secondary osteon--the dominant microstructural component of the cortical bone tissue--is considered as an n-layered cylinder with...
A model is developed whereby the secondary osteon--the dominant microstructural component of the cortical bone tissue--is considered as an n-layered cylinder with internal stresses in linear isotropic elasticity. An exact solution is obtained for a loading condition represented by a tensile-compressive force. The lengthening, the side deformation, and the strain energy of the system are explicitly calculated. The behavior of the main elastic quantities is illustrated by graphs. In particular, the important role played by the parity of the number of lamellae is revealed.
Topics: Algorithms; Elasticity; Haversian System; Humans; Models, Biological; Poisson Distribution; Pressure; Stress, Mechanical; Tensile Strength
PubMed: 7738052
DOI: 10.1016/0021-9290(94)00082-f -
Journal of Biomechanics Jan 2013Cortical bone has a hierarchical structure, spanning from the macrostructure at several millimeters or whole bone level, the microstructure at several hundred...
Cortical bone has a hierarchical structure, spanning from the macrostructure at several millimeters or whole bone level, the microstructure at several hundred micrometers level, to the nanostructure at hydroxyapatite (HAp) crystals and collagen fibrils levels. The aim of the study is to understand the relationship between the HAp crystal orientation and the elastic modulus and the relationship between the osteon area fraction and the deformation behavior of HAp crystals in cortical bone. In the experiments, five strip specimens (40×2×1mm(3)) aligned with the bone axis were taken from the cortical bone of a bovine femur. The degree of c-axis orientation of HAp crystals in the specimens was measured with the X-ray diffraction technique with the imaging plate. To measure the deformation behavior of HAp crystals in the specimens, tensile tests under X-ray irradiation were conducted. The specimens were cut at the X-ray measurement positions and osteon area fraction and porosity at the transverse cross-sections were observed. Further, the volume fraction of HAp of the specimens was measured. Results showed the degree of c-axis orientation of HAp crystals was positively correlated with the elastic modulus of the specimens (r=0.94). The volume fraction of HAp and the porosity showed no statistical correlation with the elastic modulus and the tensile strength. The HAp crystal strain ε(H) increased linearly with the bone tissue strain ε. The average value of ε(H)/ε was 0.69±0.13 and there was no correlation between the osteon area fraction and ε(H)/ε (r=-0.27, p=0.33). The results suggest that the degree of c-axis orientation of HAp crystals affects the elastic modulus and the magnitude of HAp crystal strain does not depend on the osteon area fraction.
Topics: Animals; Bone Density; Cattle; Crystallization; Durapatite; Elastic Modulus; Femur; Haversian System; Porosity; Radiography; Tensile Strength
PubMed: 23084783
DOI: 10.1016/j.jbiomech.2012.09.020 -
Biomedical Engineering Online Jul 2018An osteon consists of a multi-layered bone matrix and interstitial fluid flow in the lacunar-canalicular system. Loading-induced interstitial fluid flow in the...
BACKGROUND
An osteon consists of a multi-layered bone matrix and interstitial fluid flow in the lacunar-canalicular system. Loading-induced interstitial fluid flow in the lacunar-canalicular system is critical for osteocyte mechanotransduction and bone remodelling.
METHODS
To investigate the effects of the lamellar structure and heterogeneous material properties of the osteon on the distributions of interstitial fluid flow and seepage velocity, an osteon is idealized as a hollow two-dimensional poroelastic multi-layered slab model subjected to cyclic loading. Based on poroelastic theory, the analytical solutions of interstitial fluid pressure and seepage velocity in lacunar-canalicular pores were obtained.
RESULTS
The results show that strain magnitude has a greater influence on interstitial fluid pressure than loading frequency. Interestingly, the heterogeneous distribution of permeability produces remarkable variations in interstitial fluid pressure and seepage velocity in the cross-section of cortical bone. In addition, interstitial fluid flow stimuli to osteocytes are mostly controlled by the value of permeability at the surface of the osteon rather than at the inner wall of the osteon.
CONCLUSION
Interstitial fluid flow induced by cycling loading stimuli to an osteocyte housed in a lacunar-canalicular pore is not only correlated with strain amplitude and loading frequency, but also closely correlated with the spatial gradient distribution of permeability. This model can help us better understand the fluid flow stimuli to osteocytes during bone remodelling.
Topics: Elasticity; Haversian System; Hydrodynamics; Mechanotransduction, Cellular; Models, Biological; Permeability; Porosity; Pressure; Weight-Bearing
PubMed: 30016971
DOI: 10.1186/s12938-018-0528-y -
Journal of Anatomy May 2011Osteon morphotype scores (MTSs) allow for quantification of mechanically important collagen/lamellar variations between secondary osteons when viewed in circularly...
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.
Topics: Adaptation, Physiological; Animals; Collagen; Femur; Haversian System; Microscopy, Polarization; Pan troglodytes; Stress, Mechanical; Weight-Bearing
PubMed: 21323667
DOI: 10.1111/j.1469-7580.2011.01348.x -
American Journal of Physical... Dec 1991Ahlqvist and Damsten's (1969) modification of the Kerley (1965) method for histological age estimation uses percent osteonal bone, rather than actual osteon counts, in...
Ahlqvist and Damsten's (1969) modification of the Kerley (1965) method for histological age estimation uses percent osteonal bone, rather than actual osteon counts, in order to eliminate the difficulty of distinguishing between intact and fragmentary osteons. Since their method has been developed for the femur only, and several more recent methods have been proposed that utilize percent osteonal bone, a study was undertaken to ascertain the relative value of percent osteonal bone compared with osteon counts to estimate age at death for the radius, tibia, and fibula. First the question of how much of the cross-section of a bone should be sampled was addressed by comparing the results of regression against age for percent osteonal bone derived from sampling only four fields with those derived from the entire cross-section of the radius. A significant age association was found only when the entire cross-section was sampled. In order to evaluate the relative merit of using either percent osteonal bone, or osteon counts to estimate age, each variable was regressed against age. Significant correlation coefficients were found for all three bones when the independent variable was osteon counts. When percent osteonal bone was employed, a significant correlation was found only for the radius. Stepwise linear regression found osteon counts for the fibula alone to be the best age predictor. Finally, a repeated measures analysis of variance revealed that percent osteonal bone and osteon counts both differ among the three bones within an individual. Based upon these results, osteon counts, rather than percent osteonal bone, should be the variable of choice when developing histological age predicting methods.
Topics: Age Determination by Skeleton; Analysis of Variance; Bone and Bones; Female; Haversian System; Humans; Male; Regression Analysis
PubMed: 1776658
DOI: 10.1002/ajpa.1330860407 -
Bone Jul 2009As computational modeling becomes an increasingly common tool for probing the regulation of bone remodeling, the need for experimental data to refine and validate such...
As computational modeling becomes an increasingly common tool for probing the regulation of bone remodeling, the need for experimental data to refine and validate such models also grows. For example, van Oers et al. (R.F. van Oers, R. Ruimerman, B. van Rietbergen, P.A. Hilbers, R. Huiskes, Relating osteon diameter to strain. Bone 2008;43: 476-482.) recently described a mechanism by which osteon size may be regulated (inversely) by strain. Empirical data supporting this relation, particularly in humans, are sparse. Therefore, we sought to determine if there is a link between body weight (the only measure related to loading available for a cadaveric population) and osteon geometry in human bone. We hypothesized that after controlling for age, sex and height, weight would be inversely related to femoral osteon size (area, On.Ar; diameter, On.Dm). Secondarily we sought to describe the relation between osteon circularity (On.Cr) and these parameters. Osteons (n=12,690) were mapped within microradiographs of femoral mid-diaphyseal specimens (n=88; 45 male, 43 female; 17-97 yrs). Univariate analysis of covariance was conducted (n=87; 1 outlier) with sex as a fixed factor and height, weight and log-transformed age as covariates. Weight was negatively related to On.Ar and On.Dm (p=0.006 and p=0.004, respectively). Age was significantly related to osteon and, it was also significantly related to circularity (all p<0.001). This relation was negative for On.Ar and On.Dm and positive for On.Cr (increasing circularity with age). On.Ar and On.Dm were found to be significantly different between the sexes (p=0.021 and p=0.019, respectively), with females having smaller osteons. No relation between sex and On.Cr was detected (p=0.449). Height was not significantly related to any of the geometric parameters. Partial eta-squared values revealed that age accounted for the largest proportion (On.Ar: 28%, On.Dm: 18%, On.Cr: 30%), weight accounted for the second largest (On.Ar: 9%, On.Dm: 10%) and sex accounted for the smallest proportion (On.Ar: 6%, On.Dm: 7%) of the variance in geometry. While previous studies have reported relations between osteon size and sex/age, we believe that our findings are the first to demonstrate a link with weight. We believe that this negative relation with weight is most probably mechanical in nature; however, alternative (endocrine) links between bone and adipose tissue cannot be ruled out by our design.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Aging; Anthropometry; Body Height; Body Weight; Female; Femur; Haversian System; Humans; Male; Middle Aged; Regression Analysis; Sex Characteristics
PubMed: 19303955
DOI: 10.1016/j.bone.2009.03.654 -
Acta Pathologica, Microbiologica, Et... Sep 1982Cross-sectional osteon size was measured in undecalcified stained sections of iliac crest bone specimens from normal individuals (n = 68) and from patients with spinal... (Comparative Study)
Comparative Study
Osteon cross-sectional size in the iliac crest: variation in normals and patients with osteoporosis, hyperparathyroidism, acromegaly, hypothyroidism and treated epilepsia.
Cross-sectional osteon size was measured in undecalcified stained sections of iliac crest bone specimens from normal individuals (n = 68) and from patients with spinal osteoporosis (n = 27), primary hyperparathyroidism (n = 23), epilepsia (receiving chronic anti-convulsant therapy) (n = 11), acromegaly (n = 18), and hypothyroidism (n = 12). In each individual the shortest osteon diameter (D) and the corresponding Haversian canal diameter (d) were measured in a minimum of 20 completed secondary osteons by means of a micrometer eyepiece. Among normal males the areas of bone resorbed and formed increased with age (p less than 0.01), owing to an increase in the thickness of bone resorbed (p less than 0.01) and an unchanged thickness of bone formed. Among the females, both the areas of bone resorbed and formed decreased with age (p less than 0.05), owing to a reduction in the thickness of bone resorbed (p less than 0.05) as well as formed (p less than 0.001). Resorbed and formed areas were reduced in the epileptic (p less than 0.01) and acromegalic (p less than 0.01) groups but increased in the hypothyroid group (p less than 0.01) compared to sex- and age-matched controls. Neither the osteoporotic nor the hyperparathyroid group showed any alterations in osteon size. The Haversian canal diameter was slightly increased in the epileptic group but normal in the other patient groups. The observed changes reflect variations in the amount of work performed by osteoclasts and osteoblasts during bone remodelling and may be explained by variations in cellular activity and bone turn-over rates.
Topics: Acromegaly; Adult; Aged; Bone Resorption; Epilepsy; Female; Haversian System; Humans; Hyperparathyroidism; Hypothyroidism; Ilium; Male; Middle Aged; Ossification, Heterotopic; Osteoblasts; Osteoclasts; Osteoporosis
PubMed: 6816007
DOI: No ID Found -
The Journal of Veterinary Medical... Feb 1999The transverse sections of radius diaphysis in an 11-year-old giant Holstein cow with dermal dysplasia of a collagen disorder-related skin fragility (Cow 1), probably...
The transverse sections of radius diaphysis in an 11-year-old giant Holstein cow with dermal dysplasia of a collagen disorder-related skin fragility (Cow 1), probably based on increasing turnover of the dermal collagen as reported previously, were morphologically and physico-chemically investigated. Cow 1 had about one and a half times as much as the body weight of normal Holstein cows, aged 5 to 6.5 years with stabilized growth. The bone samples were compared with those of a 12-year-old Holstein cow as controls (Cow 2). It has been reported that the long-bone diaphysis of young calves and some herbivorous dinosaurs are occupied with laminar bone showing a concentric appositional formation, and that such a laminar bone is characteristically seen during the growing period of some farm animals and large dogs that show very rapid growth rates. Cow 1 had a smaller number of osteons than Cow 2 in the outer-half layer of the diaphysis, and showed an intermediate type between Cow 2 and a 1-year-old Holstein ox in the entire layers, although their bone volumes were similar among them. There were no significant differences in Ca and P concentrations and the Vickers microhardness values between the bone matrix of Cow 1 and Cow 2. The bone-collagen fibrils of Cow 1 showed uneven diameters and a disordered arrangement. Thus, there may be some relation in collagen formation between the bone matrix of Cow 1 and the dermis. From the remaining volume of laminar bone, Cow 1, aged 11 years, had probably shown growth until quite recently, so that we consider that Cow 1 became a giant animal, in the same way as some herbivorous dinosaurs.
Topics: Animals; Bone and Bones; Cattle; Cattle Diseases; Collagen; Diaphyses; Female; Haversian System; Male; Microscopy, Electron, Scanning; Radius; Skin Diseases
PubMed: 10081745
DOI: 10.1292/jvms.61.101 -
Journal of Biomechanics 2006Measurement of the elastic properties of single osteon lamellae is still one of the most demanding tasks in bone mechanics to be solved. By means of site-matched Raman...
Measurement of the elastic properties of single osteon lamellae is still one of the most demanding tasks in bone mechanics to be solved. By means of site-matched Raman microspectroscopy, acoustic microscopy and nanoindentation the structure, chemical composition and anisotropic elasticity of individual lamellae in secondary osteons were investigated. Acoustic impedance images (911-MHz) and two-dimensional Raman spectra were acquired in sections of human femoral bone. The samples were prepared with orientations at various observation angles theta relative to the femoral long axis. Nanoindentations provided local estimations of the elastic modulus and landmarks necessary for spatial fusion of the acoustic and spectral Raman images. Phosphate nu(1) (961 cm(-1)) and amide I (1665 cm(-1)) band images representing spatial distributions of mineral and collagen were fused with the acoustic images. Acoustic impedance was correlated with the indentation elastic modulus E(IT) (R(2)=0.61). Both parameters are sensitive to elastic tissue anisotropy. The lowest values were obtained in the direction perpendicular to the femoral long axis. Acoustic images exhibit a characteristic bimodal lamellar pattern of alternating high and low impedance values. Since this undulation was not associated with a variation of the phosphate nu(1)-band intensity in the Raman images, it was attributed to variations of the lamellar orientation. After threshold segmentation and conversion to elastic modulus the orientation and transverse isotropic elastic constants were derived for individual ensembles of apparent thin and thick lamellae. Our results suggest that this model represents the effective anisotropic properties of an asymmetric twisted plywood structure made of transverse isotropic fibrils. This is the first report that proves experimentally the ability of acoustic microscopy to map tissue elasticity in two dimensions with micrometer resolution. The combination with Raman microspectroscopy provides a unique way to study bone and mineral metabolism and the relation with mechanical function at the ultrastructural tissue level.
Topics: Anisotropy; Bone Density; Bone Matrix; Elasticity; Femur; Haversian System; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Stress, Mechanical; Ultrasonography; Weight-Bearing
PubMed: 16144702
DOI: 10.1016/j.jbiomech.2005.07.009