scholarly journals Distinct Characteristics of Mandibular Bone Collagen Relative to Long Bone Collagen: Relevance to Clinical Dentistry

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Takashi Matsuura ◽  
Kentaro Tokutomi ◽  
Michiko Sasaki ◽  
Michitsuna Katafuchi ◽  
Emiri Mizumachi ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Matrix Protein ◽  
Relative Strength ◽  
Bone Collagen ◽  
Long Bone ◽  
Osteogenic Potential ◽  
Lower Amount ◽  
Long Bones ◽  
Distinctive Features ◽  
Lysine Hydroxylation

Bone undergoes constant remodeling throughout life. The cellular and biochemical mechanisms of bone remodeling vary in a region-specific manner. There are a number of notable differences between the mandible and long bones, including developmental origin, osteogenic potential of mesenchymal stem cells, and the rate of bone turnover. Collagen, the most abundant matrix protein in bone, is responsible for determining the relative strength of particular bones. Posttranslational modifications of collagen, such as intermolecular crosslinking and lysine hydroxylation, are the most essential determinants of bone strength, although the amount of collagen is also important. In comparison to long bones, the mandible has greater collagen content, a lower amount of mature crosslinks, and a lower extent of lysine hydroxylation. The great abundance of immature crosslinks in mandibular collagen suggests that there is a lower rate of cross-link maturation. This means that mandibular collagen is relatively immature and thus more readily undergoes degradation and turnover. The greater rate of remodeling in mandibular collagen likely renders more flexibility to the bone and leaves it more suited to constant exercise. As reviewed here, it is important in clinical dentistry to understand the distinctive features of the bones of the jaw.

scholarly journals Collagen heterogeneity within different growth regions of long bones of rachitic and nonrachitic chicks

1972 ◽  
Vol 127 (4) ◽  
pp. 715-720 ◽  
Author(s):  
Bryan P. Toole ◽  
Andrew H. Kang ◽  
Robert L. Trelstad ◽  
Jerome Gross
Keyword(s):  
Vitamin D ◽  
Amino Acid ◽  
Bone Matrix ◽  
Bone Collagen ◽  
Long Bone ◽  
Long Bones ◽  
Collagen Structure ◽  
Collagen Molecules ◽  
Relationship Of ◽  
Chain Type

The different anatomical regions involved in osteogenesis in the chick long bone have been examined for heterogeneities in collagen structure that might relate to the mechanism of ossification. Experimentally induced lathyrism was employed to enhance collagen solubility, and vitamin D deficiency to allow accumulation of osteoid, the precursor of bone matrix. The extractable lathyritic collagens of the cartilaginous and osseous regions of growing long bones from rachitic and non-rachitic chicks were examined for α-chain type and amino acid composition. In both groups of animals the growth plate and cartilaginous regions of the epiphysis gave collagen molecules of the constitution [α1(II)]3, whereas the ossifying regions contained [α1(I)]2 α2. The degree of hydroxylation of the lysine moieties was increased by approximately 50% in the α1(I)-chain and α2-chain of rachitic bone collagen. Since uncalcified osteoid is greatly enriched in rachitic bone, it is concluded that the collagen of osteoid has the configuration [α1(I)]2 α2, similar to that of bone matrix, but has an elevated hydroxylysine content. The possible relationship of this difference to the mechanism of calcification is discussed.

Longitudinal bone growth in vitro: effects of insulin-like growth factor I and growth hormone

1991 ◽  
Vol 124 (5) ◽  
pp. 602-607 ◽  
Author(s):  
Ben A. A. Scheven ◽  
Nicola J. Hamilton
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Bone Growth ◽  
Long Bone ◽  
Long Bones ◽  
Insulin Like Growth Factor ◽  
Serum Free ◽  
Factor I ◽  
Igf I

Abstract. Longitudinal growth was studied using an in vitro model system of intact rat long bones. Metatarsal bones from 18- and 19-day-old rat fetuses, entirely (18 days) or mainly (19 days) composed of chondrocytes, showed a steady rate of growth and radiolabelled thymidine incorporation for at least 7 days in serum-free media. Addition of recombinant human insulin-like growth factor-I to the culture media resulted in a direct stimulation of the longitudinal growth. Recombinant human growth hormone was also able to stimulate bone growth, although this was generally accomplished after a time lag of more than 2 days. A monoclonal antibody to IGF-I abolished both the IGF-I and GH-stimulated growth. However, the antibody had no effect on the growth of the bone explants in control, serum-free medium. Unlike the fetal long bones, bones from 2-day-old neonatal rats were arrested in their growth after 1-2 days in vitro. The neonatal bones responded to IGF-I and GH in a similar fashion as the fetal bones. Thus in this study in vitro evidence of a direct effect of GH on long bone growth via stimulating local production of IGF by the growth plate chondrocytes is presented. Furthermore, endogenous growth factors, others than IGFs, appear to play a crucial role in the regulation of fetal long bone growth.

scholarly journals Exposure to the RXR agonist SR11237 in early life causes disturbed skeletal morphogenesis in a rat model

2019 ◽  
Author(s):  
Holly Dupuis ◽  
Michael Andrew Pest ◽  
Ermina Hadzic ◽  
Thin Xuan Vo ◽  
Daniel B. Hardy ◽  
...  
Keyword(s):  
Growth Plate ◽  
Bone Growth ◽  
Long Bone ◽  
Tunel Staining ◽  
Long Bones ◽  
Micro Computed Tomography ◽  
Computed Tomography Scanning ◽  
Calcified Tissue ◽  
Trap Staining ◽  
Tomography Scanning

AbstractLongitudinal bone growth occurs through endochondral ossification (EO), controlled by various signaling molecules. Retinoid X Receptor (RXR) is a nuclear receptor with important roles in cell death, development, and metabolism. However, little is known about its role in EO. In this study, the agonist SR11237 was used to evaluate RXR activation on EO.Rats given SR11237 from post-natal day 5 to 15 were harvested for micro-computed tomography scanning and histology. In parallel, newborn CD1 mouse tibiae were cultured with increasing concentrations of SR11237 for histological and whole mount evaluation.RXR agonist-treated rats were smaller than controls, and developed dysmorphia of the growth plate. Cells invading the calcified and dysmorphic growth plate appeared pre-hypertrophic in size and shape corresponding with P57 immunostaining. Additionally, SOX9 positive cells were found surrounding the calcified tissue. The epiphysis of SR11237 treated bones showed increased TRAP staining, and additional TUNEL staining at the osteo-chondral junction. MicroCT revealed morphological disorganization in the long bones of treated animals. Isolated mouse long bones treated with SR11237 grew significantly less than their DMSO controls.This study demonstrates that stimulation of the RXR receptor causes irregular ossification, premature closure of the growth plate, and disrupted long bone growth in rodent models.

scholarly journals The first report of direct skeletal attachment method applying for tibia prosthetic leg in a chicken by cortical screw

2019 ◽  
Vol 2 (3) ◽  
pp. 3-5
Author(s):  
Piyabongkarn Damrongdej
Keyword(s):  
Stainless Steel ◽  
Blood Loss ◽  
Endotracheal Tube ◽  
Surgical Procedure ◽  
Small Animal ◽  
Long Bone ◽  
Long Bones ◽  
First Report ◽  
Cortical Screw ◽  
Intramedullary Screw

This is the first report of successful method for direct skeletal attachment for invent tibia prosthetic leg in a chicken amputee by using 3.0 mm stainless steel cortical screw as an intramedullary bone stem for right tibia endoprosthesis leg part and using acrylic with some part of endotracheal tube as an exoprosthesis leg part. This surgery was performed in a chicken amputee without bone cement using. A chicken could stand and sometime walk after 15 days of surgery. No complication problem with a screw’s stump. This intramedullary bone stem technique by a screw can adapt using in other parts of long bone animal amputee. This technique can apply for invent endoprosthesis limb in other small animal amputees and can use intramedullary screw technique with other long bones such as femur, humerus, radius, and ulna because this technique uses only one stainless 316L screw so the surgery cost is not too much. The surgical procedure is not complicated and blood loss during surgery is not much so the risk for this technique is low.

Classification of Fractures of Long Bones in the Dog and Cat: Introduction and Clinical Application

1990 ◽  
Vol 03 (02) ◽  
pp. 41-50 ◽  
Author(s):  
M. Unger ◽  
P. M. Montavon ◽  
U. F. A. Heim
Keyword(s):  
Bone Fractures ◽  
Reliable Data ◽  
Long Bone ◽  
Small Animals ◽  
Long Bones ◽  
Coding System ◽  
Fracture Classification ◽  
Fracture Criteria ◽  
Filing System

AbstractA computer filing system for the classification of fractured long bones in dogs and cats is described. It includes definitions of terms and a method of classification, based on fracture criteria seen on radiographs. This fracture classification was adapted from the AO/ASIF classification in man, to accomodate the special requirements of small animals. The localization and morphology of fractures were characterized with defined conventional terms, in order to assign an alpha-numeric code to each fracture. This coding system may also be used for computer filing of the data. With this classification system, the fractures are ranked in increasing severity and complexity for the various anatomical locations. This provides some prognostic and therapeutic informations. The system was used to code 1038 radiographically documented long bone fractures in dogs and cats. The distribution of fractures, with regard to their localization and morphology, was recorded. The system was easy to apply and proved to be able to supply valuable and reliable data.A computer filing system for the classification of fractured long bones in dogs and cats is described.

scholarly journals Alendronate Can Improve Bone Alterations in Experimental Diabetes by Preventing Antiosteogenic, Antichondrogenic, and Proadipocytic Effects of AGEs on Bone Marrow Progenitor Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Sara Rocío Chuguransky ◽  
Ana María Cortizo ◽  
Antonio Desmond McCarthy
Keyword(s):  
Bone Marrow ◽  
Experimental Diabetes ◽  
Bone Microarchitecture ◽  
Bone Matrix ◽  
Diabetic Rats ◽  
Long Bone ◽  
Osteogenic Potential ◽  
Bone Marrow Progenitor

Bisphosphonates such as alendronate are antiosteoporotic drugs that inhibit the activity of bone-resorbing osteoclasts and secondarily promote osteoblastic function. Diabetes increases bone-matrix-associated advanced glycation end products (AGEs) that impair bone marrow progenitor cell (BMPC) osteogenic potential and decrease bone quality. Here we investigated the in vitro effect of alendronate and/or AGEs on the osteoblastogenic, adipogenic, and chondrogenic potential of BMPC isolated from nondiabetic untreated rats. We also evaluated the in vivo effect of alendronate (administered orally to rats with insulin-deficient Diabetes) on long-bone microarchitecture and BMPC multilineage potential. In vitro, the osteogenesis (Runx2, alkaline phosphatase, type 1 collagen, and mineralization) and chondrogenesis (glycosaminoglycan production) of BMPC were both decreased by AGEs, while coincubation with alendronate prevented these effects. The adipogenesis of BMPC (PPARγ, intracellular triglycerides, and lipase) was increased by AGEs, and this was prevented by coincubation with alendronate. In vivo, experimental Diabetes (a) decreased femoral trabecular bone area, osteocyte density, and osteoclastic TRAP activity; (b) increased bone marrow adiposity; and (c) deregulated BMPC phenotypic potential (increasing adipogenesis and decreasing osteogenesis and chondrogenesis). Orally administered alendronate prevented all these Diabetes-induced effects on bone. Thus, alendronate could improve bone alterations in diabetic rats by preventing the antiosteogenic, antichondrogenic, and proadipocytic effects of AGEs on BMPC.

scholarly journals Disentangling mechanisms involved in collagen pyridinoline cross-linking: The immunophilin FKBP65 is critical for dimerization of lysyl hydroxylase 2

2016 ◽  
Vol 113 (26) ◽  
pp. 7142-7147 ◽  
Author(s):  
Rutger A. F. Gjaltema ◽  
Miesje M. van der Stoel ◽  
Miriam Boersema ◽  
Ruud A. Bank
Keyword(s):  
Posttranslational Modifications ◽  
Molecular Level ◽  
Splice Variants ◽  
Active Form ◽  
Connective Tissue Disorder ◽  
Cross Linking ◽  
Ppiase Activity ◽  
Lysyl Hydroxylase ◽  
Bruck Syndrome ◽  
Lysine Hydroxylation

Collagens are subjected to extensive posttranslational modifications, such as lysine hydroxylation. Bruck syndrome (BS) is a connective tissue disorder characterized at the molecular level by a loss of telopeptide lysine hydroxylation, resulting in reduced collagen pyridinoline cross-linking. BS results from mutations in the genes coding for lysyl hydroxylase (LH) 2 or peptidyl-prolyl cis-trans isomerase (PPIase) FKBP65. Given that the immunophilin FKBP65 does not exhibit LH activity, it is likely that LH2 activity is somehow dependent on FKPB65. In this report, we provide insights regarding the interplay between LH2 and FKBP65. We found that FKBP65 forms complexes with LH2 splice variants LH2A and LH2B but not with LH1 and LH3. Ablating the catalytic activity of FKBP65 or LH2 did not affect complex formation. Both depletion of FKBP65 and inhibition of FKBP65 PPIase activity reduced the dimeric (active) form of LH2 but did not affect the binding of monomeric (inactive) LH2 to procollagen Iα1. Furthermore, we show that LH2A and LH2B cannot form heterodimers with each other but are able to form heterodimers with LH1 and LH3. Collectively, our results indicate that FKBP65 is linked to pyridinoline cross-linking by specifically mediating the dimerization of LH2. Moreover, FKBP65 does not interact with LH1 and LH3, explaining why in BS triple-helical hydroxylysines are not affected. Our results provide a mechanistic link between FKBP65 and the loss of pyridinolines and may hold the key to future treatments for diseases related to collagen cross-linking anomalies, such as fibrosis and cancer.

Modal Frequencies of Long Tibia Bones: Heterogeneous vs Homogeneous Material Considerations

2017 ◽  
Author(s):  
Reem A. Yassine ◽  
Mohammad Karim Elham ◽  
Samir Mustapha ◽  
Ramsey F. Hamade
Keyword(s):  
Heterogeneous Material ◽  
Approximate Solutions ◽  
3D Models ◽  
Long Bone ◽  
Homogeneous Material ◽  
Long Bones ◽  
Bone Properties ◽  
Stiffness Properties ◽  
Mode 2 ◽  
Experimental Values

Where heterogeneous material considerations may yield more accurate estimates of long bones’ modal characteristics, homogeneous description has the advantage for yielding faster approximate solutions. In this study, modal frequencies of (bovine) long tibia bones are numerically estimated using the finite element method (FEM) using ANSYS starting from anatomically accurate CT scans and 3D models. Whole long bones are segmented into their cortical and cancellous constituents based on Hounsfield (HU) values. Bones’ cortical and cancellous constituents are first treated as heterogeneous material. Relative to stiffness-density relations, stiffness values are assigned for each element yielding a stiffness-graded structure. Modal frequencies are generated and values compared to those measured from dynamic experiments. Analysis was repeated where bone properties are homogenized by averaging the stiffness properties of bone constituents. The resulting frequencies are compared with those of the heterogeneous stiffness-graded bones. As compared with measured experimental values of one control long bone, the heterogeneous material assumption returned good estimates of the frequency values in the CC plane with of +0.85 % for mode 1 and +10.66 % for mode 2. For homogeneous material assumption, underestimates were returned with error values of −13.25% and −0.13 % differences for mode 2. In the ML plane, heterogeneous material assumption returned good estimates of the frequency values with −8.89 % for mode 1 and + 1.01 % for mode 2. Homogeneous material assumption underestimated the frequency values with error of −20.52 % for mode 1 and −7.50 % for mode 2. Homogeneous simplifications yielded faster and more memory-efficient FEM runs with heterogeneous modal analysis requiring 1.5 more running time and twice the utilized memory.

Test Methods for Accurate and Robust Material Property Measurements of Rodent Cortical Bone

2008 ◽  
Author(s):  
Douglas J. Adams ◽  
Svetlana Lublinsky ◽  
Mauricio Barrero
Keyword(s):  
Cortical Bone ◽  
Material Property ◽  
Statistical Power ◽  
Test Methods ◽  
Standard Test ◽  
Long Bone ◽  
Long Bones ◽  
Tissue Properties ◽  
Serial Test ◽  
Direct Measurements

Direct measurements of cortical bone material properties are difficult to achieve in rodent long bones due to the inherently small dimensions and difficulties in machining standard test specimen geometries [1]. Bone tissue properties in nearly all rodent studies are thus limited to estimates from flexural tests of long bone diaphyses. In addition to the inaccuracies imposed by the bending stress state itself, these material property estimates are further confounded by the non-uniform geometry of long bones along the diaphyseal length. The goal of this work was to develop a series of techniques to improve the accuracy and precision of material property measurements in rodent long bones, with explicit mathematical correction for geometrical complexity and multiple measurements from individual bones. In combination, these techniques provide a pragmatic serial test routine for collecting multiple direct measurements of cortical tissue elastic modulus and strength, with a potential for improving sensitivity and statistical power in skeletal studies using rodents.

scholarly journals Do Systemic Factors Influence the Fate of Nonunions to Become Atrophic? A Retrospective Analysis of 162 Cases

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Markus Rupp ◽  
Stefanie Kern ◽  
Thaqif El Khassawna ◽  
Abdullah Ismat ◽  
Deeksha Malhan ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Scientific Evidence ◽  
Fibrous Tissue ◽  
Patient Characteristics ◽  
The Elderly ◽  
Long Bone ◽  
Osteogenic Potential ◽  
Accompanying Injuries ◽  
Systemic Factors ◽  
Atrophic Nonunion

Introduction. Nonunions are a challenge for orthopedic surgeons. In hypertrophic nonunions, improvement of mechanical stability usually is the satisfactory treatment, whereas in atrophic nonunions improvement of the biological environment is most important. However, scientific evidence revealed that “avital” nonunions are not avascular and fibrous tissue contains cells with osteogenic potential. To find out if systemic factors suppress this intrinsic potential in atrophic nonunions, this study compares characteristics of hypertrophic with atrophic nonunion patients. Methods. We analyzed medical records of 162 surgically treated patients suffering from aseptic long bone nonunions. Atrophic and hypertrophic nonunions were distinguished by absence or presence of callus and calcification in the fracture gap. Mechanical implant loosening and patient characteristics such as age, gender, and body mass index were assessed. Fracture classification according to AO/OTA, open and closed fractures, and osteosynthesis were recorded. In addition, comorbidities and allergies between both groups were compared. Results. A higher number of hypertrophic nonunion patients were male with often allergies. Hypertrophic nonunion occurred more often after intramedullary nailing compared to atrophic nonunions. Atrophic nonunion patients being nonallergic were significantly older than nonallergic patients suffering from hypertrophic nonunions. In both atrophic and hypertrophic nonunion patients, age was lower in patients with accompanying injuries compared with age of patients with isolated fractures. Conclusion. Systemic factors influence development of nonunion types. In nonallergic patients, atrophic nonunions occur more often in the elderly. This manuscript is a first step to identify different factors which might influence the nature of nonunion. To enable nonunion treatment which is tailored to individual patient characteristics, further prospective studies with more sophisticated research methods are necessary.

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