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Journal of Materials Science. Materials... Mar 2017Animal bones bear varied impact loadings during in the movements of animals. The impact resistance and micro-damage of bones are influenced by their various...
Animal bones bear varied impact loadings during in the movements of animals. The impact resistance and micro-damage of bones are influenced by their various microstructures at different length scales. In this paper, according to the microstructure of osteon, three 2-D microstructure models (circumferential ellipse lacunae (Model A), radial elliptical lacunae (Model B) and circular lacunae (Model C) were constructed for investigating the influences of the arranged direction and shape of osteocyte lacunae on resisting impact and micro-damage. Impact analytical results show that the maximal stress of the Model A is the minimum and that of the Model B is the maximal under same boundary conditions, which indicates that the circumferentially elliptical lacunae, whose minor axis is along the radial direction of the osteon (Model A), can enhance impact resistance of osteons effectively. The investigated results of the progressive damage show that the circumferentially ellipse lacunae (Model A) are more benefit to resist micro-damage and that the micro-cracks in the model are mainly along the circumferential direction of the osteon. These investigated results for the novel microstructures found in osteon can serve engineers as guidance in the designs of biomimetic and bioinspired tubular structures or materials for engineering applications.
Topics: Animals; Biomimetics; Cattle; Femur; Haversian System; Humans; Microscopy, Electron, Scanning; Models, Theoretical; Nanostructures; Osteocytes; Tissue Engineering
PubMed: 28144850
DOI: 10.1007/s10856-017-5850-6 -
Journal of the American Geriatrics... May 1964
Topics: Aging; Bone Resorption; Bone and Bones; Growth; Haversian System; Humans; Kinetics; Microscopy; Osteogenesis; Ribs
PubMed: 14157682
DOI: 10.1111/j.1532-5415.1964.tb05726.x -
Anatomical Record (Hoboken, N.J. : 2007) Aug 2013Intracortical bone remodeling is persistent throughout life, leading to age related increases in osteon population density (OPD). Intracortical porosity also increases... (Comparative Study)
Comparative Study
Intracortical bone remodeling is persistent throughout life, leading to age related increases in osteon population density (OPD). Intracortical porosity also increases with age in many mammals including humans, contributing to bone fragility and fracture risk. Unbalanced bone resorption and formation during disuse (e.g., physical inactivity) also increases intracortical porosity. In contrast, hibernating bears are a naturally occurring model for the prevention of both age-related and disuse osteoporoses. Intracortical bone remodeling is decreased during hibernation, but resorption and formation remain balanced. Black bears spend 0.25-7 months in hibernation annually depending on climate and food availability. We found longer hibernating bears demonstrate lower OPD and higher cortical bone mineralization than bears with shorter hibernation durations, but we surprisingly found longer hibernating bears had higher intracortical porosity. However, bears from three different latitudes showed age-related decreases in intracortical porosity, indicating that regardless of hibernation duration, black bears do not show the disuse- or age-related increases in intracortical porosity which is typical of other animals. This ability to prevent increases in intracortical porosity likely contributes to their ability to maintain bone strength during prolonged periods of physical inactivity and throughout life. Improving our understanding of the unique bone metabolism in hibernating bears will potentially increase our ability to develop treatments for age- and disuse-related osteoporoses in humans.
Topics: Aging; Animals; Bone Density; Bone Remodeling; Bone Resorption; Femur; Florida; Haversian System; Hibernation; Male; Models, Animal; Osteogenesis; Porosity; Time Factors; Ursidae; Utah; West Virginia
PubMed: 23728917
DOI: 10.1002/ar.22720 -
The Journal of Bone and Joint Surgery.... Oct 1966
Topics: Animals; Bone and Bones; Capillaries; Dogs; Haversian System; Microscopy, Electron; Osteoblasts; Osteoclasts; Osteocytes; Osteogenesis
PubMed: 5921783
DOI: No ID Found -
Journal of the Mechanical Behavior of... May 2012Variations in Young's modulus of individual lamellae around a single bone osteon have been measured in three orthogonal planes by nanoindentation. The objective of these...
Variations in Young's modulus of individual lamellae around a single bone osteon have been measured in three orthogonal planes by nanoindentation. The objective of these measurements was to establish a correlation between the mechanical properties and the microstructure of the osteonal lamellae. When indentation was performed in a plane perpendicular to the osteon axis (OA), the modulus of the lamella closest to the canal appears to be higher than the modulus of all other lamellae. No such difference was observed in planes parallel to the OA. However, in the parallel planes, an unexpected asymmetry in modulus was detected on opposing sides of the canal, potentially supporting the validity of the rotated plywood structure model of bone lamellae. Finally, based on the experimentally measured Young's modulus values, most osteonal lamellae appear to exhibit structural anisotropy.
Topics: Animals; Anisotropy; Biocompatible Materials; Biomechanical Phenomena; Bone Substitutes; Bone and Bones; Elastic Modulus; Femur; Haversian System; Horses; Humans; Imaging, Three-Dimensional; Ions; Male; Materials Testing; Microscopy, Atomic Force; Models, Theoretical; Nanotechnology; Stress, Mechanical
PubMed: 22498296
DOI: 10.1016/j.jmbbm.2012.01.014 -
Biofabrication Mar 2024Scaffolds for bone tissue engineering should enable regeneration of bone tissues with its native hierarchically organized extracellular matrix (ECM) and multiple tissue...
Scaffolds for bone tissue engineering should enable regeneration of bone tissues with its native hierarchically organized extracellular matrix (ECM) and multiple tissue interfaces. To achieve this, inspired by the structure and properties of bone osteon, we fabricated polyhydroxybutyrate (PHB)-based mineralized electrospun fibrous scaffolds. After studying multiple PHB-based fibers, we chose 7%PHB/1%Gelatin fibers (PG) to fabricate mineralized fibers that mimic mineralized collagen fibers in bone. The mineralized PG (mPG) surface had a rough, hydrophilic layer of low crystalline calcium phosphate which was biocompatible to bone marrow stromal cells (BMSCs), induced their proliferation and was osteoinductive. Subsequently, by modulating the electrospinning process, we fabricated mPG-based novel higher order fibrous scaffolds that mimic the macroscale geometries of osteons of bone ECM. Inspired by the aligned collagen fibers in bone lamellae, we fabricated mPG scaffolds with aligned fibers that could direct anisotropic elongation of mouse BMSC (mBMSCs). Further, we fabricated electrospun mPG-based osteoinductive tubular constructs which can mimic cylindrical bone components like osteons or lamellae or be used as long bone analogues based on their dimensions. Finally, to regenerate tissue interfaces in bone, we introduced a novel bi-layered scaffold-based approach. An electrospun bi-layered tubular construct that had PG in the outer layer and 7%PHB/0.5%Polypyrrole fibers (PPy) in the inner layer was fabricated. The bi-layered tubular construct underwent preferential surface mineralization only on its outer layer. This outer mineralized layer supported osteogenesis while the inner PPy layer could support neural cell growth. Thus, the bi-layered tubular construct may be used to regenerate haversian canal in the osteons which hosts nerve fibers. Overall, the study introduced novel techniques to fabricate biomimetic structures that can regenerate components of bone osteon and its multiple tissue interfaces. The study lays foundation for the fabrication of a modular scaffold that can regenerate bone with its hierarchical structure and complex tissue interfaces.
Topics: Mice; Animals; Tissue Engineering; Tissue Scaffolds; Haversian System; Polymers; Polyhydroxybutyrates; Polyesters; Pyrroles; Bone and Bones; Collagen
PubMed: 38471166
DOI: 10.1088/1758-5090/ad331a -
Pathology Oncology Research : POR 2000Blood formation by pluripotent stem cells and their progeny is thought to be regulated by receptor-ligand interactions between cell-substrate, cell-cell and cell-matrix... (Review)
Review
Blood formation by pluripotent stem cells and their progeny is thought to be regulated by receptor-ligand interactions between cell-substrate, cell-cell and cell-matrix in the bone marrow. Primitive stem cells form progenitors and, in their turn, these give rise to haemopoietic progeny which are more specifically committed in that they can form progressively fewer types of blood cells. Recently we have established that direct cell-cell communication via gap junctions may be part of this regulatory system. Connexin43 gap junctions metabolically couple the three dimensional meshwork of bone marrow stromal cells to form a functional syncytium in which some blood-forming cells are also coupled. The expression of gap junctions in the bone marrow is markedly upregulated when there is an urgent and substantial demand for blood-formation; for example, following cytotoxic injury after 5-fluorouracil or irradiation; or during neonatal blood-formation and in the epiphysis of growing bones. Chemical blockade of gap junctions blocks blood-formation in long-term cultures but is reversible after the blockade has been relieved. This short review highlights briefly the known regulatory mechanisms of blood-formation with especial attention to gap junctional communication.
Topics: Animals; Cell Communication; Connexin 43; Extracellular Matrix; Gap Junctions; Haversian System; Hematopoiesis; Hematopoietic Cell Growth Factors; Humans; Integrins; Mice; Up-Regulation
PubMed: 11173655
DOI: 10.1007/BF03187326 -
Brief communication: Test of a method to identify double-zonal osteon in polarized light microscopy.American Journal of Physical... Oct 2018Double-zonal osteons (DZ) have been of interest in paleopathological research because they might be linked to physiological pathology. DZ are thought to be evidence of...
OBJECTIVES
Double-zonal osteons (DZ) have been of interest in paleopathological research because they might be linked to physiological pathology. DZ are thought to be evidence of arrested osteon formation with a brief but abrupt increase in mineralization of lamellae occurring during bone remodeling. Originally identified from microradiographs as hypermineralized rings, recent studies have identified DZ from linear polarized light microscopy (PLM). However, PLM does not guarantee the adequate detection of DZ since PLM captures bone birefringence and not hyper-mineralization. Scanning electron microscopy with backscatter electrons (BSE-SEM) allows observation of DZ by detecting differences in mineralization. The purpose of this study is to investigate whether DZ, as identified by BSE-SEM, can indeed be identified with PLM.
MATERIALS AND METHODS
The sample consists of an archaeological collection of adult midshaft femurs (n = 30) from St. Matthew cemetery, Quebec City (1771-1860). DZ were identified and counted independently with PLM and BSE-SEM for the same sections. Results from both methods were compared.
RESULTS
Chi-square test shows that there was no significant difference between the two methods (p = 0.404). No significant bias was found on Bland-Altman analysis and Cohen's kappa shows a substantial agreement between the two methods (Κ = 0.66). PLM shows a good accuracy (sensitivity 79%, specificity 99.4%) and reliability (Positive Predictive Value: 86.71%; Negative Predictive Value: 99.45%).
DISCUSSION
These findings indicate that the two methods are interchangeable. PLM, using our proposed protocol, is reliable to accurately identify DZ. We discuss how PLM and BSE-SEM that measure different features of the bone tissue can converge on the identification of DZ.
Topics: Adult; Anthropology, Physical; Femur; Haversian System; Humans; Microscopy, Electron, Scanning; Microscopy, Polarization; Sensitivity and Specificity
PubMed: 30132791
DOI: 10.1002/ajpa.23616 -
American Journal of Physical... Sep 2012Distinguishing human from non-human bone fragments is usually accomplished by observation of gross morphology. When macroscopic analysis is insufficient, histological...
Distinguishing human from non-human bone fragments is usually accomplished by observation of gross morphology. When macroscopic analysis is insufficient, histological approaches can be applied. Microscopic features, like plexiform bone or osteon banding, are characteristic of non-humans. In the absence of such features, distinguishing Haversian bone as either human or non-human proves problematic. This study proposes a histomorphometric approach for classifying species from Haversian bone. Two variables, osteon area (On.Ar.) and circularity (On.Cr.), are examined. Measurements were collected from three species (deer, dog, human) represented by various skeletal elements; only ribs were available for humans (ribs: deer n = 6, dog n = 6, human n = 26; humeri: deer n = 6, dog n = 6; femora: deer n = 6, dog n = 6). Qualitative analysis comparing human to non-human On.Ar. demonstrated that human ribs have larger mean On.Ar. (0.036 mm(2)) than non-human ribs (deer = 0.017 mm(2) , dog = 0.013 mm(2)). On.Cr. in the ribs showed minor differences between species (deer = 0.877; dog = 0.885; human = 0.898). Results demonstrated no significant difference across long bone quadrants in long bones. Discriminant analyses run on the means for each sample demonstrated overlap in deer and dog samples, clustering the non-human and human groups apart from each other. Mean On.Cr. proved a poor criterion (ribs only: 76.3%, pooled elements: 66.1%), while mean On.Ar. proved useful in identifying human from non-human samples (ribs only: 92.1%, pooled elements: 93.5%). When variables were combined, accuracy increased to 100% correct classification for rib data and 98.4% when considering data from all elements. These results indicate that On.Ar. and On.Cr. are valuable histomorphometric tools for distinguishing human from non-human Haversian bone.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Bone and Bones; Deer; Dogs; Epiphyses; Female; Haversian System; Histology, Comparative; Humans; Male; Middle Aged; Species Specificity; Statistics, Nonparametric
PubMed: 22700390
DOI: 10.1002/ajpa.22097 -
Acta Anatomica 1978The predominant collagen fiber orientation in newly formed osteons was determined by polarized light microscopy. Osteons were classified into five categories according...
The predominant collagen fiber orientation in newly formed osteons was determined by polarized light microscopy. Osteons were classified into five categories according to the proportion of their cross section formed by dark lamellae. In dark lamellae most fibers run longitudinally or on a step spiral while they follow a circular or shallow spiral course in light lamellae. Types 1 and 2 are 'light' osteons; types 4 and 5 are 'dark', and type 3 is 'intermediate'. A significant correlation was found between the predominant collagen fiber orientation in osteons and the age at which their formation occurs. Significant differences were found also in the collagen fiber orientation in osteons among the different quadrants of the same bone.
Topics: Adult; Aged; Aging; Collagen; Haversian System; Humans; Middle Aged; Tibia
PubMed: 899668
DOI: 10.1159/000144890