Comparative study on inorganic composition and crystallographic properties of cortical and cancellous bone.

Science.gov (United States)

Wang, Xiao-Yan; Zuo, Yi; Huang, Di; Hou, Xian-Deng; Li, Yu-Bao

2010-12-01

To comparatively investigate the inorganic composition and crystallographic properties of cortical and cancellous bone via thermal treatment under 700 °C. Thermogravimetric measurement, infrared spectrometer, X-ray diffraction, chemical analysis and X-ray photo-electron spectrometer were used to test the physical and chemical properties of cortical and cancellous bone at room temperature 250 °C, 450 °C, and 650 °C, respectively. The process of heat treatment induced an extension in the a-lattice parameter and changes of the c-lattice parameter, and an increase in the crystallinity reflecting lattice rearrangement after release of lattice carbonate and possible lattice water. The mineral content in cortical and cancellous bone was 73.2wt% and 71.5wt%, respectively. For cortical bone, the weight loss was 6.7% at the temperature from 60 °C to 250 °C, 17.4% from 250 °C to 450 °C, and 2.7% from 450 °C to 700 °C. While the weight loss for the cancellous bone was 5.8%, 19.9%, and 2.8 % at each temperature range, the Ca/P ratio of cortical bone was 1.69 which is higher than the 1.67 of stoichiometric HA due to the B-type CO₃²⁻ substitution in apatite lattice. The Ca/P ratio of cancellous bone was lower than 1.67, suggesting the presence of more calcium deficient apatite. The collagen fibers of cortical bone were arrayed more orderly than those of cancellous bone, while their mineralized fibers ollkded similar. The minerals in both cortical and cancellous bone are composed of poorly crystallized nano-size apatite crystals with lattice carbonate and possible lattice water. The process of heat treatment induces a change of the lattice parameter, resulting in lattice rearrangement after the release of lattice carbonate and lattice water and causing an increase in crystal size and crystallinity. This finding is helpful for future biomaterial design, preparation and application. Copyright © 2010 The Editorial Board of Biomedical and Environmental Sciences

Bone augmentation for cancellous bone- development of a new animal model

Science.gov (United States)

2013-01-01

Background Reproducible and suitable animal models are required for in vivo experiments to investigate new biodegradable and osteoinductive biomaterials for augmentation of bones at risk for osteoporotic fractures. Sheep have especially been used as a model for the human spine due to their size and similar bone metabolism. However, although sheep and human vertebral bodies have similar biomechanical characteristics, the shape of the vertebral bodies, the size of the transverse processes, and the different orientation of the facet joints of sheep are quite different from those of humans making the surgical approach complicated and unpredictable. Therefore, an adequate and safe animal model for bone augmentation was developed using a standardized femoral and tibia augmentation site in sheep. Methods The cancellous bone of the distal femur and proximal tibia were chosen as injection sites with the surgical approach via the medial aspects of the femoral condyle and proximal tibia metaphysis (n = 4 injection sites). For reproducible drilling and injection in a given direction and length, a custom-made c-shaped aiming device was designed. Exact positioning of the aiming device and needle positioning within the intertrabecular space of the intact bone could be validated in a predictable and standardized fashion using fluoroscopy. After sacrifice, bone cylinders (∅ 32 mm) were harvested throughout the tibia and femur by means of a diamond-coated core drill, which was especially developed to harvest the injected bone area exactly. Thereafter, the extracted bone cylinders were processed as non-decalcified specimens for μCT analysis, histomorphometry, histology, and fluorescence evaluation. Results The aiming device could be easily placed in 63 sheep and assured a reproducible, standardized injection area. In four sheep, cardiovascular complications occurred during surgery and pulmonary embolism was detected by computed tomography post surgery in all of these animals

Microstructural Assessment of Cancellous Bone Using 3D Microtomography

International Nuclear Information System (INIS)

Silva A M H; Alves J M; Da Silva O L; Silva Junior N F; Gazziro M; Pereira J C; Lasso P R O; Vaz C M P; Pereira C A M; Leiva T P; Guarniero R

2011-01-01

Cancellous bones have a porous microstructure and can be modeled as linear elastic solid, heterogeneous and anisotropic. Few studies regarding the morphometric analysis of trabecular bone samples with 3D microtomography have been published so far. The technique has spread worldwide for the characterization of trabecular structures in studies related to bone quality and its relationship with metabolic diseases bone like osteoporosis. In our study cancellous bone samples with cubic and cylindrical geometry were extracted from bovine femur were used to investigate the structural arrangement of bone through high resolution x-ray 3D microtomography (μCT). Four trabecular microstructural parameters (tissue volume, bone volume, bone volume fraction and tissue surface) were measured by 2D (stereological method) and 3D morphometric analysis using the software CTan Analyser supplied by the manufacturer of the microtomograph (SkyScan, model 1172, Belgium). The measurements were done in three main directions (superior-inferior, medial-lateral and anterior-posterior) to investigate the correlation between the 2D and 3D morphometric analysis. The results show a high correlation between the analysis. The x-ray 3D microtomography technique has a great potential for the assessment of bone quality.

Application of INAA in the assessment of selected elements in cancellous bone of human iliac crest

International Nuclear Information System (INIS)

Zaichick, V.

2007-01-01

The effect of age and sex was investigated on the concentration of chemical elements in intact cancellous bone of iliac crest of 74 relatively healthy, 15-55 years old women (n = 29) and men (n = 45). Concentrations of Ca, Cl, K, Mg, Mn, Na, P, and Sr in bone samples were determined by instrumental neutron activation analysis using short-lived radionuclides. Mean values (M±S.E.M.) of the mass fraction of the investigated elements (on dry weight basis) for female and male all together were: 127±4 g/kg, 1620±80 mg/kg, 1310±70 mg/kg, 1550±50 mg/kg, <0.32±0.02 mg/kg, 4240±110 mg/kg, 61.8±1.8 g/kg, and 235±18 mg/kg, respectively. The statistically significant (≤0.05) decrease of Ca, Mg, and P concentrations in the iliac cancellous bone with age was found only for women. Sex-related comparison has shown that the mean values of Mg mass fractions in male bone samples were less than in female ones. (author)

Radiographic healing and remodelling of cortical and cancellous bone grafts after rigid plate fixation

International Nuclear Information System (INIS)

Waris, P.; Karaharju, E.; Slaetis, P.; Paavolainen, P.

1980-01-01

Cortical and cancellous interposition grafts, with rigid plate fixation, in the tibiofibular bones of 130 rabbits were followed radiographically for one year. The cancellous grafts healed earlier, but by 12 weeks both graft types had been incorporated, the distal host-graft interface being the last to heal. Progressive cancellous transformation in both the graft and host bone led to an increased over-all bone diameter, a widened medullary canal and a thinned porotic wall. (Auth.)

X-treme CT analysis of cancellous bone at the rotator cuff insertion in human individuals with osteoporosis: superficial versus deep quality.

Science.gov (United States)

Kirchhoff, Chlodwig; Kirchhoff, Sonja; Sprecher, Christoph M; Ahrens, Philipp; Imhoff, Andreas B; Hinterwimmer, Stefan; Milz, Stefan; Braunstein, Volker

2013-03-01

Rotator cuff (RC) repair-especially in the elderly population-is problematic since the patients suffer to a high extent from bone mineral density loss at the reattachment site. Therefore, the study was primarily driven by the question whether it is possible to reach more or qualitatively better cancellous bone and thus a more stable postoperative result if anchors with greater length are used for RC repair and/or the conventional anchors are screwed deeper into the bone. In anatomical terms, the question is raised whether cancellous bone is of better quality close to or far off the RC enthesis. Axial HRqCT scans (X-tremeCT, Scanco Medical) of 36 human cadaveric humeral heads (75 ± 11 years) were performed to determine the ratio of bone volume to total volume (BV/TV), trabecular thickness (Trab Th), number of trabecles (Trab N), trabecular separation (Trab Sp) as well as non-metric indices such as connectivity density (Conn Dens) and structure model index (SMI). Within the greater tuberosity (GT), 6 volumes of interest (VOI) (A1, B1, C1, A2, B2, C2), in the lesser tuberosity (LT) 2 VOIs (D1, D2) and one control VOI in the subchondral bone were set. The analyzed bone cylinder of each VOI was divided into a superficial and a deep portion. The parameters BV/TV, Trab N, Trab Th and Conn Dens in all volumes of the GT and LT revealed higher values in the superficial portion reaching different levels of significance (p significance for the non-metric parameter SMI in no volume of the GT/LT, although the higher values were found superficially. Our data show that cancellous bone presents with decreasing bone quality when analyzing increasingly deeper portions of the bone cylinders of the GT and LT starting at the articular surface. This information seems to be crucial for shoulder surgeons, especially when treating elderly patients. Our results clearly prove that screwing in anchors to a deeper extent will not improve stability, since the deeper bone stock is of worse

An Ultrasonic Backscatter Instrument for Cancellous Bone Evaluation in Neonates

Directory of Open Access Journals (Sweden)

Chengcheng Liu

2015-09-01

Full Text Available Ultrasonic backscatter technique has shown promise as a noninvasive cancellous bone assessment tool. A novel ultrasonic backscatter bone diagnostic (UBBD instrument and an in vivo application for neonatal bone evaluation are introduced in this study. The UBBD provides several advantages, including noninvasiveness, non-ionizing radiation, portability, and simplicity. In this study, the backscatter signal could be measured within 5 s using the UBBD. Ultrasonic backscatter measurements were performed on 467 neonates (268 males and 199 females at the left calcaneus. The backscatter signal was measured at a central frequency of 3.5 MHz. The delay (T1 and duration (T2 of the backscatter signal of interest (SOI were varied, and the apparent integrated backscatter (AIB, frequency slope of apparent backscatter (FSAB, zero frequency intercept of apparent backscatter (FIAB, and spectral centroid shift (SCS were calculated. The results showed that the SOI selection had a direct influence on cancellous bone evaluation. The AIB and FIAB were positively correlated with the gestational age (|R| up to 0.45, P10 µs. Moderate positive correlations (|R| up to 0.45, P10 µs. The T2 mainly introduced fluctuations in the observed correlation coefficients. The moderate correlations observed with UBBD demonstrate the feasibility of using the backscatter signal to evaluate neonatal bone status. This study also proposes an explicit standard for in vivo SOI selection and neonatal cancellous bone assessment.

Effects of Spaceflight on Bone: The Rat as an Animal Model for Human Bone Loss

Science.gov (United States)

Halloran, B.; Weider, T.; Morey-Holton, E.

1999-01-01

The loss of weight bearing during spaceflight results in osteopenia in humans. Decrements in bone mineral reach 3-10% after as little as 75-184 days in space. Loss of bone mineral during flight decreases bone strength and increases fracture risk. The mechanisms responsible for, and the factors contributing to, the changes in bone induced by spaceflight are poorly understood. The rat has been widely used as an animal model for human bone loss during spaceflight. Despite its potential usefulness, the results of bone studies performed in the rat in space have been inconsistent. In some flights bone formation is decreased and cancellous bone volume reduced, while in others no significant changes in bone occur. In June of 1996 Drs. T. Wronski, S. Miller and myself participated in a flight experiment (STS 78) to examine the effects of glucocorticoids on bone during weightlessness. Technically the 17 day flight experiment was flawless. The results, however, were surprising. Cancellous bone volume and osteoblast surface in the proximal tibial metaphysis were the same in flight and ground-based control rats. Normal levels of cancellous bone mass and bone formation were also detected in the lumbar vertebrae and femoral neck of flight rats. Furthermore, periosteal bone formation rate was found to be identical in flight and ground-based control rats. Spaceflight had little or no effect on bone metabolism! These results prompted us to carefully review the changes in bone observed in, and the flight conditions of previous spaceflight missions.

Histologic Evaluation of Wound Healing After Ridge Preservation With Cortical, Cancellous, and Combined Cortico-Cancellous Freeze-Dried Bone Allograft: A Randomized Controlled Clinical Trial.

Science.gov (United States)

Demetter, Randy S; Calahan, Blaine G; Mealey, Brian L

2017-09-01

Cortical and cancellous mineralized freeze-dried bone allografts (FDBA) are available for use in alveolar ridge preservation after tooth extraction. There are currently no data regarding use of a combination 50%/50% cortico-cancellous FDBA compared with a 100% cortical or 100% cancellous FDBA in ridge preservation. The primary objective of this study is to dimensionally and histologically evaluate healing after ridge preservation in non-molar sites using 50%/50% cortico-cancellous FDBA versus 100% cortical and 100% cancellous FDBA. Sixty-six patients requiring extraction of a non-molar tooth were enrolled and randomized into three groups to receive ridge preservation with the following: 1) 100% cortical FDBA; 2) 100% cancellous FDBA; or 3) 50%/50% cortico-cancellous FDBA. After 18 to 20 weeks of healing, a biopsy was harvested, and an implant was placed. The alveolar ridge was measured pre- and postoperatively to evaluate change in ridge height and width. Percentages of vital bone, residual graft, and connective tissue (CT)/other were determined via histomorphometric analysis. Histomorphometric analysis revealed no significant differences among groups regarding percentage of vital bone or CT/other. The 100% cortical FDBA group had significantly greater residual graft material (P = 0.04). Dimensional analysis revealed no significant between-group differences in any parameter measured. To the best knowledge of the authors, this study offers the first histologic evidence demonstrating no significant difference in vital bone formation or dimensional changes among 50%/50% cortico-cancellous FDBA, 100% cortical FDBA, and 100% cancellous FDBA when used in ridge preservation of non-molar tooth sites.

Defect nonunion of a metatarsal bone fracture in a cow: successful management with bone plating and autogenous cancellous bone graft.

Science.gov (United States)

Raghunath, M; Singh, N; Singh, T; Gopinathan, A; Mohindroo, J; Atri, K

2013-01-01

A two-and-half-year-old cow was presented with a defect nonunion of the right metatarsal III/IV bone following a severely comminuted open fracture two months previously. The animal underwent open fixation using a 4.5 mm, broad, 10-hole, dynamic compression plate and autogenous cancellous bone graft collected from the contralateral iliac shaft. The animal started partial weight bearing after the third postoperative day and resumed complete weight bearing after the 10th day. Fracture healing was complete and the implants were removed after the 120th postoperative day. Stable fixation by means of a bone plate in conjunction with a cancellous bone graft facilitated complete healing and restoration of the bone column of the defect and the metatarsal fracture. The animal made a complete recovery.

Empirical angle-dependent Biot and MBA models for acoustic anisotropy in cancellous bone

International Nuclear Information System (INIS)

Lee, Kang ll; Hughes, E R; Humphrey, V F; Leighton, T G; Choi, Min Joo

2007-01-01

The Biot and the modified Biot-Attenborough (MBA) models have been found useful to understand ultrasonic wave propagation in cancellous bone. However, neither of the models, as previously applied to cancellous bone, allows for the angular dependence of acoustic properties with direction. The present study aims to account for the acoustic anisotropy in cancellous bone, by introducing empirical angle-dependent input parameters, as defined for a highly oriented structure, into the Biot and the MBA models. The anisotropy of the angle-dependent Biot model is attributed to the variation in the elastic moduli of the skeletal frame with respect to the trabecular alignment. The angle-dependent MBA model employs a simple empirical way of using the parametric fit for the fast and the slow wave speeds. The angle-dependent models were used to predict both the fast and slow wave velocities as a function of propagation angle with respect to the trabecular alignment of cancellous bone. The predictions were compared with those of the Schoenberg model for anisotropy in cancellous bone and in vitro experimental measurements from the literature. The angle-dependent models successfully predicted the angular dependence of phase velocity of the fast wave with direction. The root-mean-square errors of the measured versus predicted fast wave velocities were 79.2 m s -1 (angle-dependent Biot model) and 36.1 m s -1 (angle-dependent MBA model). They also predicted the fact that the slow wave is nearly independent of propagation angle for angles about 50 0 , but consistently underestimated the slow wave velocity with the root-mean-square errors of 187.2 m s -1 (angle-dependent Biot model) and 240.8 m s -1 (angle-dependent MBA model). The study indicates that the angle-dependent models reasonably replicate the acoustic anisotropy in cancellous bone

Pharmacokinetics of Cefuroxime in Cortical and Cancellous Bone Obtained by Microdialysis - a Porcine Study

DEFF Research Database (Denmark)

Tøttrup, Mikkel; Forsingdal Hardlei, Tore; Bendtsen, Michael

2014-01-01

. As reference, free and total plasma concentrations were also measured. The animals received a bolus of 1500 mg cefuroxime over 30 min. No significant differences between key pharmacokinetic parameters for sealed and unsealed drill holes in cortical bone were found. The mean area under the concentration...... (MD) technique for measurement of cefuroxime in bone, and to obtain pharmacokinetic profiles for the same drug in porcine cortical and cancellous bone. Measurements were conducted in bone-wax sealed and unsealed drill holes in cortical bone, in drill holes in cancellous bone and in subcutaneous tissue...

Dynamic Mechanical Testing Techniques for Cortical and Cancellous Bone

Science.gov (United States)

Cloete, Trevor

2017-06-01

Bone fracture typically occurs as an impact loading event (sporting accidents, vehicle collisions), the simulation of which requires in-depth understanding of dynamic bone behavior. Bone is a natural composite material with a complex multi length-scale hierarchical microstructure. At a macroscopic level, it is classified into hard/compact cortical bone and soft/spongy cancellous (trabecular) bone, though both are low-impedance materials relative to steels. Cortical bone is predominant in long bones, while in complex bone geometries (joints, flat bones) a cancellous bone core supports a thin cortical shell. Bone has primarily been studied at quasi-static strain rates (ɛ˙ failure, with interrupted quasi-static tests revealing a strong microstructure dependence. However, bone specimens are typically destroyed during dynamic tests, leading to a lack of dynamic microstructural damage investigations. In this paper, a short overview of dynamic bone testing is presented to give context to the challenges of testing low impedance, strain-rate dependent, non-linear, visco-elastic-brittle materials. Recent state-of-the-art experimental developments in dynamic bone testing are reviewed, with emphasis on pulse shaping, momentum trapping and ISR testing. These techniques allow for dynamic bone testing at small strains and near-constant strain rates with intact specimen recovery. The results are compared to those obtained with varying strain rate tests. Interrupted dynamic test results with microstructural analysis of the recovered specimens are presented and discussed. The paper concludes with a discussion of the experimental and modeling challenges that lie ahead in the field of dynamic bone behavior. The financial assistance of the National Research Foundation and the University of Cape Town towards this research is hereby acknowledged. Opinions expressed and conclusions arrived at are those of the author alone.

Changed morphology and mechanical properties of cancellous bone in the mandibular condyles of edentate people

DEFF Research Database (Denmark)

Ding, Ming

2004-01-01

Since edentate subjects have a reduced masticatory function, it can be expected that the morphology of the cancellous bone of their mandibular condyles has changed according to the altered mechanical environment. In the present study, the morphology of cylindrical cancellous bone specimens...

Comparison of bioengineered human bone construct from four sources of osteogenic cells.

Science.gov (United States)

Ng, Angela Min-Hwei; Saim, Aminuddin Bin; Tan, Kok-Keong; Tan, G H; Mokhtar, Sabarul Afian; Rose, Isa Mohamed; Othman, Fauziah; Idrus, Ruszymah Binti Haji

2005-01-01

Osteoprogenitor cells have been reported to be present in periosteum, cancellous and cortical bone, and bone marrow; but no attempt to identify the best cell source for bone tissue engineering has yet been reported. In this study, we aimed to investigate the growth and differentiation pattern of cells derived from these four sources in terms of cell doubling time and expression of osteoblast-specific markers in both monolayer cells and three-dimensional cell constructs in vitro. In parallel, human plasma derived-fibrin was evaluated for use as biomaterial when forming three-dimensional bone constructs. Our findings showed osteoprogenitor cells derived from periosteum to be most proliferative followed by cortical bone, cancellous bone, and then bone marrow aspirate. Bone-forming activity was observed in constructs formed with cells derived from periosteum, whereas calcium deposition was seen throughout the constructs formed with cells derived from cancellous and cortical bones. Although no mineralization activity was seen in constructs formed with osteoprogenitor cells derived from bone marrow, well-organized lacunae as would appear in the early phase of bone reconstruction were noted. Scanning electron microscopy evaluation showed cell proliferation throughout the fibrin matrix, suggesting the possible application of human fibrin as the bioengineered tissue scaffold at non-load-bearing sites.

Glucocorticoid induced osteopenia in cancellous bone of sheep: validation of large animal model for spine fusion and biomaterial research.

Science.gov (United States)

Ding, Ming; Cheng, Liming; Bollen, Peter; Schwarz, Peter; Overgaard, Søren

2010-02-15

Glucocorticoid with low calcium and phosphorus intake induces osteopenia in cancellous bone of sheep. To validate a large animal model for spine fusion and biomaterial research. A variety of ovariectomized animals has been used to study osteoporosis. Most experimental spine fusions were based on normal animals, and there is a great need for suitable large animal models with adequate bone size that closely resemble osteoporosis in humans. Eighteen female skeletal mature sheep were randomly allocated into 3 groups, 6 each. Group 1 (GC-1) received prednisolone (GC) treatment (0.60 mg/kg/day, 5 times weekly) for 7 months. Group 2 (GC-2) received the same treatment as GC-1 for 7 months followed by 3 months without treatment. Group 3 was left untreated and served as the controls. All sheep received restricted diet with low calcium and phosphorus during experiment. After killing the animals, cancellous bone specimens from the vertebra, femurs, and tibias were micro-CT scanned and tested mechanically. Serum biomarkers were determined. In lumbar vertebra, the GC treatment resulted in significant decrease of cancellous bone volume fraction and trabecular thickness, and bone strength. However, the microarchitecture and bone strength of GC-2 recovered to a similar level of the controls. A similar trend of microarchitectural changes was also observed in the distal femur and proximal tibia of both GC treated sheep. The bone formation marker serum-osteocalcin was largely reduced in GC-1 compared to the controls, but recovered with a rebound increase at month 10 in GC-2. The current investigation demonstrates that the changes in microarchitecture and mechanical properties were comparable with those observed in humans after long-term GC treatment. A prolonged GC treatment is needed for a long-term observation to keep osteopenic bone. This model resembles long-term glucocorticoid treated osteoporotic model, and is useful in preclinical studies.

Accuracy of cancellous bone volume fraction measured by micro-CT scanning

DEFF Research Database (Denmark)

Ding, Ming; Odgaard, A; Hvid, I

1999-01-01

Volume fraction, the single most important parameter in describing trabecular microstructure, can easily be calculated from three-dimensional reconstructions of micro-CT images. This study sought to quantify the accuracy of this measurement. One hundred and sixty human cancellous bone specimens...... which covered a large range of volume fraction (9.8-39.8%) were produced. The specimens were micro-CT scanned, and the volume fraction based on Archimedes' principle was determined as a reference. After scanning, all micro-CT data were segmented using individual thresholds determined by the scanner...

Cosserat moduli of anisotropic cancellous bone : A micromechanical analysis

NARCIS (Netherlands)

Fatemi, J.; Onck, P.R.; Poort, G.; Van Keulen, F.

A micromechanical-based approach is proposed to quantify the effective (in the macroscopic sense) elastic constants of Cosserat materials. The material under investigation (cancellous bone) is cellular and classically elastic at the microscopic level and assumed to be dense Cosserat elastic at the

Effects of gas produced by degradation of Mg–Zn–Zr Alloy on cancellous bone tissue

Energy Technology Data Exchange (ETDEWEB)

Wang, Jingbo; Jiang, Hongfeng [Tianjin Hospital, 300211 Tianjin (China); Bi, Yanze; Sun, Jin e; Chen, Minfang; Liu, Debao [School of Materials Science and Engineering, Tianjin University of Technology, 300384 Tianjin (China)

2015-10-01

Mg–Zn–Zr alloy cylinders were implanted into the femoral condyles of Japanese big-ear white rabbits. X-ray showed that by 12 weeks following implantation the implant became obscure, around which the low-density area appeared and enlarged. By 24 weeks, the implant was more obscure and the density of the surrounding cancellous bone increased. Scanning electron microscopy examination showed bone tissue on the surface of the alloy attached by living fibers at 12 weeks. Micro-CT confirmed that new bone tissue on the surface of the residual alloy implant increased from 12 weeks to 24 weeks. By 12 weeks, many cavities in the cancellous bone tissue around the implant were noted with a CT value, similar to gas value, and increasing by 24 weeks (P < 0.01). Histological examination of hard tissue slices showed that bone tissue was visibly attached to the alloy in the femoral condyle at 12 weeks. The trabecular bone tissues became more intact and dense, and the cavities were filled with soft tissue at 24 weeks. In general, gas produced by the degradation of the Mg–Zn–Zr alloy can cause cavitation within cancellous bone, which does not affect osteogenesis of Mg alloy. - Highlights: • The degradation of Mg alloy in cancellous bone causes cavitation around the alloy. • At first, the CT value of the cavities is similar to the gas value. • The area of the cavities enlarges gradually by 12 weeks. • The cavities are filled with bone tissue and soft tissue gradually.

Material heterogeneity in cancellous bone promotes deformation recovery after mechanical failure.

Science.gov (United States)

Torres, Ashley M; Matheny, Jonathan B; Keaveny, Tony M; Taylor, David; Rimnac, Clare M; Hernandez, Christopher J

2016-03-15

Many natural structures use a foam core and solid outer shell to achieve high strength and stiffness with relatively small amounts of mass. Biological foams, however, must also resist crack growth. The process of crack propagation within the struts of a foam is not well understood and is complicated by the foam microstructure. We demonstrate that in cancellous bone, the foam-like component of whole bones, damage propagation during cyclic loading is dictated not by local tissue stresses but by heterogeneity of material properties associated with increased ductility of strut surfaces. The increase in surface ductility is unexpected because it is the opposite pattern generated by surface treatments to increase fatigue life in man-made materials, which often result in reduced surface ductility. We show that the more ductile surfaces of cancellous bone are a result of reduced accumulation of advanced glycation end products compared with the strut interior. Damage is therefore likely to accumulate in strut centers making cancellous bone more tolerant of stress concentrations at strut surfaces. Hence, the structure is able to recover more deformation after failure and return to a closer approximation of its original shape. Increased recovery of deformation is a passive mechanism seen in biology for setting a broken bone that allows for a better approximation of initial shape during healing processes and is likely the most important mechanical function. Our findings suggest a previously unidentified biomimetic design strategy in which tissue level material heterogeneity in foams can be used to improve deformation recovery after failure.

Compressive behaviour of gyroid lattice structures for human cancellous bone implant applications

International Nuclear Information System (INIS)

Yánez, A.; Herrera, A.; Martel, O.; Monopoli, D.; Afonso, H.

2016-01-01

Electron beam melting (EBM) was used to fabricate porous titanium alloy structures. The elastic modulus of these porous structures was similar to the elastic modulus of the cancellous human bone. Two types of cellular lattice structures were manufactured and tested: gyroids and diamonds. The design of the gyroid structures was determined by the main angle of the struts with respect to the axial direction. Thus, structures with angles of between 19 and 68.5° were manufactured. The aim of the design was to reduce the amount of material needed to fabricate a structure with the desired angles to increase the range of stiffness of the scaffolds. Compression tests were conducted to obtain the elastic modulus and the strength. Both parameters increased as the angle decreased. Finally, the specific strength of the gyroid structures was compared with that of the diamond structures and other types of structures. It is shown that, for angles lower than 35°, the gyroid structures had a high strength to weight ratios. - Highlights: • Gyroid and diamond lattice structures were fabricated by electron beam melting. • Compression tests were conducted to obtain the elastic modulus and the strength. • Some gyroid structures show a higher specific strength than other types of structures.

Compressive behaviour of gyroid lattice structures for human cancellous bone implant applications

Energy Technology Data Exchange (ETDEWEB)

Yánez, A., E-mail: alejandro.yanez@ulpgc.es [Department of Mechanical Engineering, University of Las Palmas de Gran Canaria (Spain); Herrera, A. [Julius Wolff Institute, Berlin (Germany); Martel, O. [Department of Mechanical Engineering, University of Las Palmas de Gran Canaria (Spain); Monopoli, D.; Afonso, H. [Department of Mechanical Engineering, Instituto Tecnológico de Canarias (Spain)

2016-11-01

Electron beam melting (EBM) was used to fabricate porous titanium alloy structures. The elastic modulus of these porous structures was similar to the elastic modulus of the cancellous human bone. Two types of cellular lattice structures were manufactured and tested: gyroids and diamonds. The design of the gyroid structures was determined by the main angle of the struts with respect to the axial direction. Thus, structures with angles of between 19 and 68.5° were manufactured. The aim of the design was to reduce the amount of material needed to fabricate a structure with the desired angles to increase the range of stiffness of the scaffolds. Compression tests were conducted to obtain the elastic modulus and the strength. Both parameters increased as the angle decreased. Finally, the specific strength of the gyroid structures was compared with that of the diamond structures and other types of structures. It is shown that, for angles lower than 35°, the gyroid structures had a high strength to weight ratios. - Highlights: • Gyroid and diamond lattice structures were fabricated by electron beam melting. • Compression tests were conducted to obtain the elastic modulus and the strength. • Some gyroid structures show a higher specific strength than other types of structures.

Numerical and experimental study on the wave attenuation in bone--FDTD simulation of ultrasound propagation in cancellous bone.

Science.gov (United States)

Nagatani, Yoshiki; Mizuno, Katsunori; Saeki, Takashi; Matsukawa, Mami; Sakaguchi, Takefumi; Hosoi, Hiroshi

2008-11-01

In cancellous bone, longitudinal waves often separate into fast and slow waves depending on the alignment of bone trabeculae in the propagation path. This interesting phenomenon becomes an effective tool for the diagnosis of osteoporosis because wave propagation behavior depends on the bone structure. Since the fast wave mainly propagates in trabeculae, this wave is considered to reflect the structure of trabeculae. For a new diagnosis method using the information of this fast wave, therefore, it is necessary to understand the generation mechanism and propagation behavior precisely. In this study, the generation process of fast wave was examined by numerical simulations using elastic finite-difference time-domain (FDTD) method and experimental measurements. As simulation models, three-dimensional X-ray computer tomography (CT) data of actual bone samples were used. Simulation and experimental results showed that the attenuation of fast wave was always higher in the early state of propagation, and they gradually decreased as the wave propagated in bone. This phenomenon is supposed to come from the complicated propagating paths of fast waves in cancellous bone.

Ultrasonic characterization of cancellous bone using apparent integrated backscatter

Energy Technology Data Exchange (ETDEWEB)

Hoffmeister, B K [Department of Physics, Rhodes College, 2000 North Parkway, Memphis, TN 38112 (United States); III, C I Jones [Department of Physics, Rhodes College, 2000 North Parkway, Memphis, TN 38112 (United States); Caldwell, G J [Department of Physics, Rhodes College, 2000 North Parkway, Memphis, TN 38112 (United States); Kaste, S C [Department of Diagnostic Imaging, St Jude Children' s Research Hospital, Memphis, TN 38105 (United States)

2006-06-07

Apparent integrated backscatter (AIB) is a measure of the frequency-averaged (integrated) backscattered power contained in some portion of a backscattered ultrasonic signal. AIB has been used extensively to study soft tissues, but its usefulness as a tissue characterization technique for cancellous bone has not been demonstrated. To address this, we performed measurements on 17 specimens of cancellous bone over two different frequency ranges using a 1 MHz and 5 MHz broadband ultrasonic transducer. Specimens were obtained from bovine tibiae and prepared in the shape of cubes (15 mm side length) with faces oriented along transverse (anterior, posterior, medial and lateral) and longitudinal (superior and inferior) principal anatomic directions. A mechanical scanning system was used to acquire multiple backscatter signals from each direction for each cube. AIB demonstrated highly significant linear correlations with bone mineral density (BMD) for both the transverse (R{sup 2} = 0.817) and longitudinal (R{sup 2} = 0.488) directions using the 5 MHz transducer. In contrast, the correlations with density were much weaker for the 1 MHz transducer (R{sup 2} = 0.007 transverse, R{sup 2} = 0.228 longitudinal). In all cases where a significant correlation was observed, AIB was found to decrease with increasing BMD.

The micro-architecture of human cancellous bone from fracture neck of femur patients in relation to the structural integrity and fracture toughness of the tissue

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C. Greenwood

2015-12-01

Full Text Available Osteoporosis is clinically assessed from bone mineral density measurements using dual energy X-ray absorption (DXA. However, these measurements do not always provide an accurate fracture prediction, arguably because DXA does not grapple with ‘bone quality’, which is a combined result of microarchitecture, texture, bone tissue properties, past loading history, material chemistry and bone physiology in reaction to disease. Studies addressing bone quality are comparatively few if one considers the potential importance of this factor. They suffer due to low number of human osteoporotic specimens, use of animal proxies and/or the lack of differentiation between confounding parameters such as gender and state of diseased bone. The present study considers bone samples donated from patients (n = 37 who suffered a femoral neck fracture and in this very well defined cohort we have produced in previous work fracture toughness measurements (FT which quantify its ability to resist crack growth which reflects directly the structural integrity of the cancellous bone tissue. We investigated correlations between BV/TV and other microarchitectural parameters; we examined effects that may suggest differences in bone remodelling between males and females and compared the relationships with the FT properties. The data crucially has shown that TbTh, TbSp, SMI and TbN may provide a proxy or surrogate for BV/TV. Correlations between FT critical stress intensity values and microarchitecture parameters (BV/TV, BS/TV, TbN, BS/BV and SMI for osteoporotic cancellous tissue were observed and are for the first time reported in this study. Overall, this study has not only highlighted that the fracture model based upon BMD could potentially be improved with inclusion of other microarchitecture parameters, but has also given us clear clues as to which of them are more influential in this role.

Bioactive Ti metal analogous to human cancellous bone: Fabrication by selective laser melting and chemical treatments.

Science.gov (United States)

Pattanayak, Deepak K; Fukuda, A; Matsushita, T; Takemoto, M; Fujibayashi, S; Sasaki, K; Nishida, N; Nakamura, T; Kokubo, T

2011-03-01

Selective laser melting (SLM) is a useful technique for preparing three-dimensional porous bodies with complicated internal structures directly from titanium (Ti) powders without any intermediate processing steps, with the products being expected to be useful as a bone substitute. In this study the necessary SLM processing conditions to obtain a dense product, such as the laser power, scanning speed, and hatching pattern, were investigated using a Ti powder of less than 45 μm particle size. The results show that a fully dense plate thinner than 1.8 mm was obtained when the laser power to scanning speed ratio was greater than 0.5 and the hatch spacing was less than the laser diameter, with a 30 μm thick powder layer. Porous Ti metals with structures analogous to human cancellous bone were fabricated and the compressive strength measured. The compressive strength was in the range 35-120 MPa when the porosity was in the range 75-55%. Porous Ti metals fabricated by SLM were heat-treated at 1300 °C for 1h in an argon gas atmosphere to smooth the surface. Such prepared specimens were subjected to NaOH, HCl, and heat treatment to provide bioactivity. Field emission scanning electron micrographs showed that fine networks of titanium oxide were formed over the whole surface of the porous body. These treated porous bodies formed bone-like apatite on their surfaces in a simulated body fluid within 3 days. In vivo studies showed that new bone penetrated into the pores and directly bonded to the walls within 12 weeks after implantation into the femur of Japanese white rabbits. The percentage bone affinity indices of the chemical- and heat-treated porous bodies were significantly higher than that of untreated implants. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

In vitro cartilage tissue engineering using cancellous bone matrix gelatin as a biodegradable scaffold

International Nuclear Information System (INIS)

Yang Bo; Yin Zhanhai; Cao Junling; Shi Zhongli; Zhang Zengtie; Liu Fuqiang; Song Hongxing; Caterson, Bruce

2010-01-01

In this study, we constructed tissue-engineered cartilage using allogeneic cancellous bone matrix gelatin (BMG) as a scaffold. Allogeneic BMG was prepared by sequential defatting, demineralization and denaturation. Isolated rabbit chondrocytes were seeded onto allogeneic cancellous BMG, and cell-BMG constructs were harvested after 1, 3 and 6 weeks for evaluation by hematoxylin and eosin staining for overall morphology, toluidine blue for extracellular matrix (ECM) proteoglycans, immunohistochemical staining for collagen type II and a transmission electron microscope for examining cellular microstructure on BMG. The prepared BMG was highly porous with mechanical strength adjustable by duration of demineralization and was easily trimmed for tissue repair. Cancellous BMG showed favorable porosity for cell habitation and metabolism material exchange with larger pore sizes (100-500 μm) than in cortical BMG (5-15 μm), allowing cell penetration. Cancellous BMG also showed good biocompatibility, which supported chondrocyte proliferation and sustained their differentiated phenotype in culture for up to 6 weeks. Rich and evenly distributed cartilage ECM proteoglycans and collagen type II were observed around chondrocytes on the surface and inside the pores throughout the cancellous BMG. Considering the large supply of banked bone allografts and relatively convenient preparation, our study suggests that allogeneic cancellous BMG is a promising scaffold for cartilage tissue engineering.

In vitro cartilage tissue engineering using cancellous bone matrix gelatin as a biodegradable scaffold

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Yang Bo; Yin Zhanhai; Cao Junling; Shi Zhongli; Zhang Zengtie; Liu Fuqiang [College of Medicine, Xi' an Jiaotong University, Yanta West Road, No 76, Yanta District, Xi' an, Shaanxi Province 710061 (China); Song Hongxing [Department of Orthopedics, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Caterson, Bruce, E-mail: caojl@mail.xjtu.edu.c [Connective Tissue Biology Laboratories, Cardiff School of Biosciences, Cardiff University, Biomedical Building, Museum Avenue, Cardiff, CF10 3US (United Kingdom)

2010-08-01

In this study, we constructed tissue-engineered cartilage using allogeneic cancellous bone matrix gelatin (BMG) as a scaffold. Allogeneic BMG was prepared by sequential defatting, demineralization and denaturation. Isolated rabbit chondrocytes were seeded onto allogeneic cancellous BMG, and cell-BMG constructs were harvested after 1, 3 and 6 weeks for evaluation by hematoxylin and eosin staining for overall morphology, toluidine blue for extracellular matrix (ECM) proteoglycans, immunohistochemical staining for collagen type II and a transmission electron microscope for examining cellular microstructure on BMG. The prepared BMG was highly porous with mechanical strength adjustable by duration of demineralization and was easily trimmed for tissue repair. Cancellous BMG showed favorable porosity for cell habitation and metabolism material exchange with larger pore sizes (100-500 {mu}m) than in cortical BMG (5-15 {mu}m), allowing cell penetration. Cancellous BMG also showed good biocompatibility, which supported chondrocyte proliferation and sustained their differentiated phenotype in culture for up to 6 weeks. Rich and evenly distributed cartilage ECM proteoglycans and collagen type II were observed around chondrocytes on the surface and inside the pores throughout the cancellous BMG. Considering the large supply of banked bone allografts and relatively convenient preparation, our study suggests that allogeneic cancellous BMG is a promising scaffold for cartilage tissue engineering.

Effects of vitamin K2 on cortical and cancellous bone mass, cortical osteocyte and lacunar system, and porosity in sciatic neurectomized rats.

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Iwamoto, Jun; Matsumoto, Hideo; Takeda, Tsuyoshi; Sato, Yoshihiro; Yeh, James K

2010-09-01

The purpose of the present study was to examine the effects of vitamin K2 on cortical and cancellous bone mass, cortical osteocyte and lacunar system, and porosity in sciatic neurectomized rats. Thirty-four female Sprague-Dawley retired breeder rats were randomized into three groups: age-matched control, sciatic neurectomy (NX), and NX + vitamin K2 administration (menatetrenone, 30 mg/kg/day p.o., three times a week). At the end of the 8-week experiment, bone histomorphometric analysis was performed on cortical and cancellous bone of the tibial diaphysis and proximal metaphysis, respectively, and osteocyte lacunar system and porosity were evaluated on cortical bone of the tibial diaphysis. NX decreased cortical and cancellous bone mass compared with age-matched controls as a result of increased endocortical and trabecular bone erosion and decreased trabecular mineral apposition rate (MAR). Vitamin K2 ameliorated the NX-induced increase in bone erosion, prevented the NX-induced decrease in MAR, and increased bone formation rate (BFR/bone surface) in cancellous bone, resulting in an attenuation of NX-induced cancellous bone loss. However, vitamin K2 did not significantly influence cortical bone mass. NX also decreased osteocyte density and lacunar occupancy and increased porosity in cortical bone compared with age-matched controls. Vitamin K2 ameliorated the NX-induced decrease in lacunar occupancy by viable osteocytes and the NX-induced increase in porosity. The present study showed the efficacy of vitamin K2 for cancellous bone mass and cortical lacunar occupancy by viable osteocytes and porosity in sciatic NX rats.

Safe Harvesting of Outer Table Parietal Bone Grafts Using an Oscillating Saw and a Bone Scraper : A Refinement of Technique for Harvesting Cortical and "Cancellous"-Like Calvarial Bone

NARCIS (Netherlands)

Schortinghuis, Jurjen; Putters, Thomas F.; Raghoebar, Gerry M.

Calvarial bone is a readily available source of bone for preimplantation augmentation procedures of the alveolar process. However, the calvaria consist mostly of cortical bone, and cancellous bone of the diploic space is scarce. A bone scraper (Safescraper Twist; META, Reggio Emilia, Italy) was used

Acetabular reconstruction with human and bovine freeze-dried bone grafts and a reinforcement device

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Ricardo Rosito

2008-01-01

Full Text Available BACKGROUND: This is a cohort trial (1997-2005 of 49 patients submitted to an acetabular component revision of a total hip arthroplasty, using impacted human and bovine freeze-dried cancellous bone grafts (H&FDBG and a reinforcement device. OBJECTIVE: To compare clinical/radiographic graft incorporation capability between cancellous bone grafts. PATIENTS/METHODS: There were two groups: I (n=26 receiving human grafts and II (n=25 receiving bovine grafts. The average follow-up times were 55 and 49 months, respectively. Clinical analysis was based on the Merle d'Aubigné and Postel score, and the radiographic analysis involved an established score based on Conn's et al. criteria for radiographic bone incorporation. RESULTS: No clinical/radiographic differences were found between the groups and both showed an overall rate of 88.5% and 76% of graft incorporation (p=0.424. CONCLUSION: The results presented here are comparable to those in the literature with the use of deep-FG. Therefore, cancellous bone grafts can be safely and adequately used in acetabular component revision in total hip arthroplasty.

Microstructures and properties of cancellous bone of avascular necrosis of femoral heads

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Yao, Xuefeng; Wang, Peng; Dai, Ruchun; Yeh, Hsien Yang

2010-03-01

The aim of this study is to investigate microscopic structure and characterize cancellous bone of avascular necrosis of the femoral head (ANFH). The rabbit model of the ANFH is established. The histopathologic features are studied successfully. The differences between the steroid-injection group (S.G.) and the controlled group (C.G.) are examined, including the weight of rabbits, the hematological examination and the three-dimensional structures. It is found that the plasma levels of cholesterol (CHO), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) in S.G. are lower than those in C.G. when the triglyceride (TG) increased in the S.G.; but the bone mineral content (BMC) and the structural model index (SMI) of the organ and tissue decreased significantly in S.G. Three-dimensional structures of the femoral head are obtained using micro-computed tomography (CT) scanning and the mechanical model is established to analyze the influences of these structural changes on the mechanical properties of the cancellous bone.

Advances in allogenic bone graft processing and usage: preparation and evaluation of chitosan-demineralized cancellous bone powder composite scaffolds as a bone graft substitute

International Nuclear Information System (INIS)

Yongyudh Vajaradul

2008-01-01

Full text: Demineralized bone matrix (DBM) is currently used by surgeons. It usually exists as a lyophilized powder which is difficult to handle and operated. In this study, we try to improve these disadvantages by combining DBM with a biomaterial. It focuses on a natural biodegradable polymer, chitosan, to act as a temporary matrix for bone growth that easily prepare in any size and shape by using tissue engineering knowledge to get a proper temporary matrix. Thus, the development of chitosan-demineralized bone powder composite scaffold is an alternative way. Polymeric scaffold has been demonstrated to have great potential for tissue engineering because the scaffold or three dimension (3D) construct provides the necessary support for cells to proliferate, extracellular matrix deposition and vascularization of neo-tissue. Moreover, chitosan, a natural cationic polymer which its structural is similar to extracellular matrix glycosaminoblycans, is biodegradable, biocompatible, non-antigenic and biofunctional. It can enhance osteoblast cells proliferation and mineral matrix deposition in culture. The first study was to fabricate and analyze composite scaffold composed of either chitosan-demineralized cancellous bone powders or chitosan-demineralized cancellous cartilage bone powders in a ratio 50:50 and 70:30 w/w (chitosan : bone powders) based on physical properties composing of average pore diameter, mechanical integrity and swelling property. Secondly, scaffolds were evaluated in term of biological properties composing of their ability to support neo osteogenesis, including assessments of cell attachment and viability, cell morphology, and the biosynthesis of extracellular matrix. Results indicated that chitosan-demineralized cancellous bone powder composite scaffolds possessing an interconnecting, porous structure could be easily created through a simple freezing and lyophilization process. (Author)

Cancellous bone structure of iliac crest biopsies following 370 days of head-down bed rest

DEFF Research Database (Denmark)

Thomsen, Jesper Skovhus; Morukov, Boris V.; Vico, Laurence

2005-01-01

INTRODUCTION: Static bone histomorphometry was applied to existing iliac bone sections originating from a 370-d 5 degrees head-down bed rest experiment. This bed rest experiment is the longest ever to have been conducted. We hypothesized that bed rest would decrease cancellous bone volume fractio...

Comparative Biomechanical and Microstructural Analysis of Native versus Peracetic Acid-Ethanol Treated Cancellous Bone Graft

Science.gov (United States)

Rauh, Juliane; Despang, Florian; Baas, Jorgen; Liebers, Cornelia; Pruss, Axel; Günther, Klaus-Peter; Stiehler, Maik

2014-01-01

Bone transplantation is frequently used for the treatment of large osseous defects. The availability of autologous bone grafts as the current biological gold standard is limited and there is a risk of donor site morbidity. Allogenic bone grafts are an appealing alternative, but disinfection should be considered to reduce transmission of infection disorders. Peracetic acid-ethanol (PE) treatment has been proven reliable and effective for disinfection of human bone allografts. The purpose of this study was to evaluate the effects of PE treatment on the biomechanical properties and microstructure of cancellous bone grafts (CBG). Forty-eight human CBG cylinders were either treated by PE or frozen at −20°C and subjected to compression testing and histological and scanning electron microscopy (SEM) analysis. The levels of compressive strength, stiffness (Young's modulus), and fracture energy were significantly decreased upon PE treatment by 54%, 59%, and 36%, respectively. Furthermore, PE-treated CBG demonstrated a 42% increase in ultimate strain. SEM revealed a modified microstructure of CBG with an exposed collagen fiber network after PE treatment. We conclude that the observed reduced compressive strength and reduced stiffness may be beneficial during tissue remodeling thereby explaining the excellent clinical performance of PE-treated CBG. PMID:24678514

Comparative biomechanical and microstructural analysis of native versus peracetic acid-ethanol treated cancellous bone graft.

Science.gov (United States)

Rauh, Juliane; Despang, Florian; Baas, Jorgen; Liebers, Cornelia; Pruss, Axel; Gelinsky, Michael; Günther, Klaus-Peter; Stiehler, Maik

2014-01-01

Bone transplantation is frequently used for the treatment of large osseous defects. The availability of autologous bone grafts as the current biological gold standard is limited and there is a risk of donor site morbidity. Allogenic bone grafts are an appealing alternative, but disinfection should be considered to reduce transmission of infection disorders. Peracetic acid-ethanol (PE) treatment has been proven reliable and effective for disinfection of human bone allografts. The purpose of this study was to evaluate the effects of PE treatment on the biomechanical properties and microstructure of cancellous bone grafts (CBG). Forty-eight human CBG cylinders were either treated by PE or frozen at -20 °C and subjected to compression testing and histological and scanning electron microscopy (SEM) analysis. The levels of compressive strength, stiffness (Young's modulus), and fracture energy were significantly decreased upon PE treatment by 54%, 59%, and 36%, respectively. Furthermore, PE-treated CBG demonstrated a 42% increase in ultimate strain. SEM revealed a modified microstructure of CBG with an exposed collagen fiber network after PE treatment. We conclude that the observed reduced compressive strength and reduced stiffness may be beneficial during tissue remodeling thereby explaining the excellent clinical performance of PE-treated CBG.

Comparative Biomechanical and Microstructural Analysis of Native versus Peracetic Acid-Ethanol Treated Cancellous Bone Graft

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Juliane Rauh

2014-01-01

Full Text Available Bone transplantation is frequently used for the treatment of large osseous defects. The availability of autologous bone grafts as the current biological gold standard is limited and there is a risk of donor site morbidity. Allogenic bone grafts are an appealing alternative, but disinfection should be considered to reduce transmission of infection disorders. Peracetic acid-ethanol (PE treatment has been proven reliable and effective for disinfection of human bone allografts. The purpose of this study was to evaluate the effects of PE treatment on the biomechanical properties and microstructure of cancellous bone grafts (CBG. Forty-eight human CBG cylinders were either treated by PE or frozen at −20°C and subjected to compression testing and histological and scanning electron microscopy (SEM analysis. The levels of compressive strength, stiffness (Young’s modulus, and fracture energy were significantly decreased upon PE treatment by 54%, 59%, and 36%, respectively. Furthermore, PE-treated CBG demonstrated a 42% increase in ultimate strain. SEM revealed a modified microstructure of CBG with an exposed collagen fiber network after PE treatment. We conclude that the observed reduced compressive strength and reduced stiffness may be beneficial during tissue remodeling thereby explaining the excellent clinical performance of PE-treated CBG.

Age-related new bone formation following the use of cancellous bone-block allografts for reconstruction of atrophic alveolar ridges.

Science.gov (United States)

Nissan, Joseph; Kolerman, Roni; Chaushu, Liat; Vered, Marilena; Naishlos, Sarit; Chaushu, Gavriel

2018-02-01

An age-related decrease in the number of osteogenic progenitor cells may compromise bone augmentation. Histomorphometrical assessment of age-related new bone formation, following atrophic alveolar ridge reconstruction, using cancellous bone-block allografts. Ninety-three consecutive patients (58 females and 35 males) were referred for implant-supported restoration of 122 severe atrophic alveolar ridges. Alveolar ridge deficiency locations were classified as anterior maxilla (n = 58), posterior maxilla (n= 32), and posterior mandible (n = 32). A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography (CT) in the posterior mandible and anterior maxilla, served as inclusion criteria. In the posterior maxilla, a residual alveolar ridge up to 4 mm vertically according to CT served as inclusion criteria. Augmentation was performed by the use of cancellous bone-block allografts. Bone biopsies (9-month posterior maxilla, 4 months anterior maxilla and posterior mandible) of young (≤40 years) versus older (>40 years) patients were histomorphometrically evaluated. In the posterior maxilla, no statistically significant histomorphometric differences were noted. While at the anterior maxilla and posterior mandible, statistically significant more newly formed bone was found in young versus older individuals, respectively (38.6% vs 19.8%, P = 0.04 and 69% vs 31%, P = .05). New bone formation following residual alveolar ridge bone grafting is age-related. Longer bone consolidation and healing time may be recommended for older individuals. © 2017 Wiley Periodicals, Inc.

Early reversal cells in adult human bone remodeling

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Abdelgawad, Mohamed Essameldin; Delaissé, Jean-Marie; Hinge, Maja

2016-01-01

The mechanism coupling bone resorption and formation is a burning question that remains incompletely answered through the current investigations on osteoclasts and osteoblasts. An attractive hypothesis is that the reversal cells are likely mediators of this coupling. Their nature is a big matter...... of debate. The present study performed on human cancellous bone is the first one combining in situ hybridization and immunohistochemistry to demonstrate their osteoblastic nature. It shows that the Runx2 and CD56 immunoreactive reversal cells appear to take up TRAcP released by neighboring osteoclasts....... Earlier preclinical studies indicate that reversal cells degrade the organic matrix left behind by the osteoclasts and that this degradation is crucial for the initiation of the subsequent bone formation. To our knowledge, this study is the first addressing these catabolic activities in adult human bone...

A deconvolution method for deriving the transit time spectrum for ultrasound propagation through cancellous bone replica models.

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Langton, Christian M; Wille, Marie-Luise; Flegg, Mark B

2014-04-01

The acceptance of broadband ultrasound attenuation for the assessment of osteoporosis suffers from a limited understanding of ultrasound wave propagation through cancellous bone. It has recently been proposed that the ultrasound wave propagation can be described by a concept of parallel sonic rays. This concept approximates the detected transmission signal to be the superposition of all sonic rays that travel directly from transmitting to receiving transducer. The transit time of each ray is defined by the proportion of bone and marrow propagated. An ultrasound transit time spectrum describes the proportion of sonic rays having a particular transit time, effectively describing lateral inhomogeneity of transit times over the surface of the receiving ultrasound transducer. The aim of this study was to provide a proof of concept that a transit time spectrum may be derived from digital deconvolution of input and output ultrasound signals. We have applied the active-set method deconvolution algorithm to determine the ultrasound transit time spectra in the three orthogonal directions of four cancellous bone replica samples and have compared experimental data with the prediction from the computer simulation. The agreement between experimental and predicted ultrasound transit time spectrum analyses derived from Bland-Altman analysis ranged from 92% to 99%, thereby supporting the concept of parallel sonic rays for ultrasound propagation in cancellous bone. In addition to further validation of the parallel sonic ray concept, this technique offers the opportunity to consider quantitative characterisation of the material and structural properties of cancellous bone, not previously available utilising ultrasound.

Defective cancellous bone structure and abnormal response to PTH in cortical bone of mice lacking Cx43 cytoplasmic C-terminus domain

Science.gov (United States)

Pacheco-Costa, Rafael; Davis, Hannah M.; Sorenson, Chad; Hon, Mary C.; Hassan, Iraj; Reginato, Rejane D.; Allen, Matthew R.; Bellido, Teresita; Plotkin, Lilian I.

2015-01-01

Connexin43 (Cx43) forms gap junction channels and hemichannels that allow the communication among osteocytes, osteoblasts, and osteoclasts. Cx43 carboxy-terminal (CT) domain regulates channel opening and intracellular signaling by acting as a scaffold for structural and signaling proteins. To determine the role of Cx43 CT domain in bone, mice in which one allele of full length Cx43 was replaced by a mutant lacking the CT domain (Cx43ΔCT/fl) were studied. Cx43ΔCT/fl mice exhibit lower cancellous bone volume but higher cortical thickness than Cx43fl/fl controls, indicating that the CT domain is involved in normal cancellous bone gain but opposes cortical bone acquisition. Further, Cx43ΔCT is able to exert the functions of full length osteocytic Cx43 on cortical bone geometry and mechanical properties, demonstrating that domains other than the CT are responsible for Cx43 function in cortical bone. In addition, parathyroid hormone (PTH) failed to increase endocortical bone formation or energy to failure, a mechanical property that indicates resistance to fracture, in cortical bone in Cx43ΔCT mice with or without osteocytic full length Cx43. On the other hand, bone mass and bone formation markers were increased by the hormone in all mouse models, regardless of whether full length or Cx43ΔCT were or not expressed. We conclude that Cx43 CT domain is involved in proper bone acquisition; and that Cx43 expression in osteocytes is dispensable for some but not all PTH anabolic actions. PMID:26409319

Swine cortical and cancellous bone: histomorphometric and densitometric characterisation

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Maria Elena Andreis

2017-06-01

Full Text Available Introduction: Swine bone morphology, composition and remodelling are similar to humans’, therefore they are considered good models in bone-related research. They have been used for several studies involving bone growth, bone and cartilage fractures and femoral head osteonecrosis. Nevertheless, the literature about pig normal bone features is incomplete. This work aims to fill the literature gaps on the microarchitecture and Bone Mineral Density (BMD of swine femoral diaphysis and distal epiphysis and tibial plateau and diaphysis. Materials and methods: Five hind limbs were collected from slaughtered 80-100 kg pigs. Microscopic analysis of cortical and cancellous bone from middle/distal femur and proximal/middle tibia was performed to determine basic histomorphometric parameters at different sites. Dual-energy X-Rays Absorptiometry was also employed to evaluate BMD. ANOVA and correlation between BMD, bone area (BA and cortical thickness were performed. Results and discussion: Diaphyseal cortical bone was mostly plexiform both in the tibia and the femur; primary/secondary osteons without clear organization were also found. Mean values for bone area, bone perimeter, trabecular width, number and separation and BMD at different anatomical sites were defined. No significant difference was found for these values at different anatomical sites. BMD proved to be positively correlated with cortical thickness (r=0,80; p<0,01. Despite the small sample size, these results seem homogeneous. They could therefore represent reference values for normal bone parameters in pigs. Applied anatomy and regenerative medicine, in fact, demand very precise information about bone micromorphology, composition and density to provide reliable indication in bone substitutes building. Moreover, since the interpretation of bone abnormalities is based on mastering normal bone characteristics, the definition of reference parameters is mandatory to avoid misinterpretation and

The penetration of cefazolin, erythromycin and methicillin into human bone tissue

DEFF Research Database (Denmark)

Sørensen, T S; Colding, H; Schroeder, E

1978-01-01

The penetration of cefazolin, erythromycin and methicillin into normal bone was studied in 20 patients undergoing surgery for fracture in the trochanteric region of the femur. The antibiotic concentrations were determined in serum, bone marrow, and cancellous and cortical bone. For all three...... antibiotics the bone marrow concentrations were of the same order of magnitude as the serum concentrations. In the eight patients receiving erythromycin, detectable concentrations were found in all the cancellous bone specimens (ranging from 1/7 to 1/2 of the serum concentration) and in three cortical bone...... specimens (ranging from 1/50 to 1/5 of the serum concentration). In the six patients receiving cefazolin, a detectable concentration was found in only one cancellous bone sample. In the six patients receiving methicillin, detectable concentrations were found only in the blood contaminated specimens of one...

Structural strength of cancellous specimens from bovine femur under cyclic compression

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Kaori Endo

2016-01-01

Full Text Available The incidence of osteoporotic fractures was estimated as nine million worldwide in 2000, with particular occurrence at the proximity of joints rich in cancellous bone. Although most of these fractures spontaneously heal, some fractures progressively collapse during the early post-fracture period. Prediction of bone fragility during progressive collapse following initial fracture is clinically important. However, the mechanism of collapse, especially the gradual loss of the height in the cancellous bone region, is not clearly proved. The strength of cancellous bone after yield stress is difficult to predict since structural and mechanical strength cannot be determined a priori. The purpose of this study was to identify whether the baseline structure and volume of cancellous bone contributed to the change in cancellous bone strength under cyclic loading. A total of fifteen cubic cancellous bone specimens were obtained from two 2-year-old bovines and divided into three groups by collection regions: femoral head, neck, and proximal metaphysis. Structural indices of each 5-mm cubic specimen were determined using micro-computed tomography. Specimens were then subjected to five cycles of uniaxial compressive loading at 0.05 mm/min with initial 20 N loading, 0.3 mm displacement, and then unloading to 0.2 mm with 0.1 mm displacement for five successive cycles. Elastic modulus and yield stress of cancellous bone decreased exponentially during five loading cycles. The decrease ratio of yield stress from baseline to fifth cycle was strongly correlated with bone volume fraction (BV/TV, r = 0.96, p < 0.01 and structural model index (SMI, r = − 0.81, p < 0.01. The decrease ratio of elastic modulus from baseline to fifth cycle was also correlated with BV/TV (r = 0.80, p < 0.01 and SMI (r = − 0.78, p < 0.01. These data indicate that structural deterioration of cancellous bone is associated with bone strength after yield stress. This study suggests that

Evaluating differential nuclear DNA yield rates and osteocyte numbers among human bone tissue types: A synchrotron radiation micro-CT approach.

Science.gov (United States)

Andronowski, Janna M; Mundorff, Amy Z; Pratt, Isaac V; Davoren, Jon M; Cooper, David M L

2017-05-01

Molecular human identification has conventionally focused on DNA sampling from dense, weight-bearing cortical bone tissue, typically from femora or tibiae. A comparison of skeletal elements from three contemporary individuals demonstrated that elements with high quantities of cancellous bone yielded nuclear DNA at the highest rates, suggesting that preferentially sampling cortical bone may be suboptimal (Mundorff & Davoren, 2014). Despite these findings, the reason for the differential DNA yields between cortical and cancellous bone tissues remains unknown. The primary goal of this work is to ascertain whether differences in bone microstructure can be used to explain differential nuclear DNA yield among bone tissue types observed by Mundorff and Davoren (2014), with a focus on osteocytes and the three-dimensional (3D) quantification of their associated lacunae. Osteocytes and other bone cells are recognized to house DNA in bone tissue, thus examining the density of their lacunae may explain why nuclear DNA yield rates differ among bone tissue types. Lacunae were visualized and quantified using synchrotron radiation-based micro-Computed Tomographic imaging (SR micro-CT). Volumes of interest (VOIs) from cortical and cancellous bone tissues (n=129) were comparatively analyzed from the three skeletons sampled for Mundorff and Davoren's (2014) study. Analyses tested the primary hypothesis that the abundance and density of osteocytes (inferred from their lacunar spaces) vary between cortical and cancellous bone tissue types. Results demonstrated that osteocyte lacunar abundance and density vary between cortical and cancellous bone tissue types, with cortical bone VOIs containing a higher lacunar abundance and density. We found that the osteocyte lacunar density values are independent of nuclear DNA yield, suggesting an alternative explanation for the higher nuclear DNA yields from bones with greater quantities of cancellous bone tissue. The use of SR micro-CT allowed for

[Fusion of reconstructed titanic plate, vertebral pedical screws and autogenous granulated cancellous bone graft in posterior occipitocervical region].

Science.gov (United States)

Zhong, Dejun; Song, Yueming

2006-08-01

To explore the technique of fusing the reconstructed titanic plate, the C2 pedical screws, and the autogenous granulated cancellous bone graft in the occipitocervical region. From April 2002 to January 2005, 19 patients aged 31-67 years with occipitocervical instability underwent the occipitocervical fusion using the reconstructed plate, C2 pedical screws, and autogenous granulated cancellous bone graft. Of the patients, 8 had complex occipitocervical deformity, 8 had old atlantoaxial fracture and dislocation, 2 had rheumatoid arthritis and anterior dislocation of the atlantoaxial joint, and 1 had cancer of the deltoid process of the axis. No complication occurred during and after operation. The follow-up for an average of 16 months in 19 patients showed that all the patients achieved solid bony fusion in the occipitocervical region. There was no broken plate, broken screw, looseness of the internal fixation or neurovascular injury. The fixation of the C2 pedical screws with the reconstructed titanic plate is reliable, the insertion is easy, and the autogenous granulated cancellous bone graft has a high fusion rate, thus resulting in a satisfactory effect in the occipitocervical fusion.

The role of an effective isotropic tissue modulus in the elastic properties of cancellous bone

NARCIS (Netherlands)

Kabel, J.; Rietbergen, van B.; Dalstra, M.; Odgaard, A.; Huiskes, H.W.J.

1999-01-01

Conceptually, the elastic characteristics of cancellous bone could be predicted directly from the trabecular morphology-or architecture-and by the elastic properties of the tissue itself. Although hardly any experimental evidence exists, it is often implicitly assumed that tissue anisotropy has a

Thermal Conductivity of Human Bone in Cryoprobe Freezing as Related to Density.

Science.gov (United States)

Walker, Kyle E; Baldini, Todd; Lindeque, Bennie G

2017-03-01

Cryoprobes create localized cell destruction through freezing. Bone is resistant to temperature flow but is susceptible to freezing necrosis at warmer temperatures than tumor cells. Few studies have determined the thermal conductivity of human bone. No studies have examined conductivity as related to density. The study goal was to examine thermal conductivity in human bone while comparing differences between cancellous and cortical bone. An additional goal was to establish a relationship between bone density and thermal conductivity. Six knee joints from 5 cadavers were obtained. The epiphyseal region was sliced in half coronally prior to inserting an argon-circulating cryoprobe directed away from the joint line. Thermistor thermometers were placed perpendicularly at measured increments, and the freezing cycle was recorded until steady-state conditions were achieved. For 2 cortical samples, the probe was placed intramedullary in metaphyseal samples and measurements were performed radially from the central axis of each sample. Conductivity was calculated using Fournier's Law and then plotted against measured density of each sample. Across samples, density of cancellous bone ranged from 0.86 to 1.38 g/mL and average thermal conductivity ranged between 0.404 and 0.55 W/mK. Comparatively, cortical bone had a density of 1.70 to 1.86 g/mL and thermal conductivity of 0.0742 to 0.109 W/mK. A strong 2-degree polynomial correlation was seen (R 2 =0.8226, P<.001). Bone is highly resistant to temperature flow. This resistance varies and inversely correlates strongly with density. This information is clinically relevant to maximize tumor ablation while minimizing morbidity through unnecessary bone loss and damage to surrounding structures. [Orthopedics. 2017; 40(2):90-94.]. Copyright 2016, SLACK Incorporated.

Human periodontal ligament stem cells cultured onto cortico-cancellous scaffold drive bone regenerative process

Directory of Open Access Journals (Sweden)

F Diomede

2016-09-01

Full Text Available The purpose of this work was to test, in vitro and in vivo, a new tissue-engineered construct constituted by porcine cortico-cancellous scaffold (Osteobiol Dual Block (DB and xeno-free ex vivo culture of human Periodontal Ligament Stem Cells (hPDLSCs. hPDLSCs cultured in xeno-free media formulation preserved the stem cells’ morphological features, the expression of stemness and pluripotency markers, and their ability to differentiate into mesenchymal lineage. Transmission electron microscopy analysis suggested that after one week of culture, both noninduced and osteogenic differentiation induced cells joined and grew on DB secreting extracellular matrix (ECM that in osteogenic induced samples was hierarchically assembled in fibrils. Quantitative RT-PCR (qRT-PCR showed the upregulation of key genes involved in the bone differentiation pathway in both differentiated and undifferentiated hPDLSCs cultured with DB (hPDLSCs/DB. Functional studies revealed a significant increased response of calcium transients in the presence of DB, both in undifferentiated and differentiated cells stimulated with calcitonin and parathormone, suggesting that the biomaterial could drive the osteogenic differentiation process of hPDLSCs. These data were confirmed by the increase of gene expression of L-type voltage-dependent Ca2+ (VDCCL, subunits α1C and α2D1 in undifferentiated cells in the presence of DB. In vivo implantation of the hPDLSCs/DB living construct in the mouse calvaria evidenced a precocious osteointegration and vascularisation process. Our results suggest consideration of DB as a biocompatible, osteoinductive and osteoconductive biomaterial, making it a promising tool to regulate cell activities in biological environments and for a potential use in the development of new custom-made tissue engineering.

Finite element analysis of dental implant loading on atrophic and non-atrophic cancellous and cortical mandibular bone - a feasibility study.

Science.gov (United States)

Marcián, Petr; Borák, Libor; Valášek, Jiří; Kaiser, Jozef; Florian, Zdeněk; Wolff, Jan

2014-12-18

The first aim of this study was to assess displacements and micro-strain induced on different grades of atrophic cortical and trabecular mandibular bone by axially loaded dental implants using finite element analysis (FEA). The second aim was to assess the micro-strain induced by different implant geometries and the levels of bone-to-implant contact (BIC) on the surrounding bone. Six mandibular bone segments demonstrating different grades of mandibular bone atrophy and various bone volume fractions (from 0.149 to 0.471) were imaged using a micro-CT device. The acquired bone STL models and implant (Brånemark, Straumann, Ankylos) were merged into a three-dimensional finite elements structure. The mean displacement value for all implants was 3.1 ±1.2 µm. Displacements were lower in the group with a strong BIC. The results indicated that the maximum strain values of cortical and cancellous bone increased with lower bone density. Strain distribution is the first and foremost dependent on the shape of bone and architecture of cancellous bone. The geometry of the implant, thread patterns, grade of bone atrophy and BIC all affect the displacement and micro-strain on the mandible bone. Preoperative finite element analysis could offer improved predictability in the long-term outlook of dental implant restorations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantification of age-related changes in the structure model type and trabecular thickness of human tibial cancellous

DEFF Research Database (Denmark)

Ding, Ming; Hvid, I

2000-01-01

Structure model type and trabecular thickness are important characteristics in describing cancellous bone architecture. It has been qualitatively observed that a radical change of trabeculae from plate-like to rod-like occurs in aging, bone remodeling, and osteoporosis. Thickness of trabeculae has...... traditionally been measured using model-based histomorphometric methods on two-dimensional (2-D) sections. However, no quantitative study has been published based on three-dimensional (3-D) methods on the age-related changes in structure model type and trabecular thickness for human peripheral (tibial......, structure model type and trabecular thickness were quantified by means of novel 3-D methods. Structure model type was assessed by calculating the structure model index (SMI). The SMI was quantified based on a differential analysis of the triangulated bone surface of a structure. This technique allows...

Experimental studies of the visualisation of spongious bone by high resolution computed tomography

International Nuclear Information System (INIS)

Henschel, M.G.; Freyschmidt, J.; Holland, B.R.

1995-01-01

18 native human lumbar vertebrae were placed in a water phantom and examined by HR-CT. The scans were compared with contact radiographs of correlating thin bone sections by morphologic criteria. The measured lower limit of visualisation of cancellous bone structures is celarly worse than expected from the measurements of spatial resolution with standard phantoms used for HR-CT (0.6 versus 0.4 mm). True and exact imaging of normal cancellous bone cannot be achieved even by modern HR-CT. Noise creates structures mimicking cancellous bone. (orig./MG) [de

Higher number of pentosidine cross-links induced by ribose does not alter tissue stiffness of cancellous bone

Energy Technology Data Exchange (ETDEWEB)

Willems, Nop M.B.K., E-mail: n.willems@acta.nl [Dept. of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam (Netherlands); Dept. of Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam (Netherlands); Langenbach, Geerling E.J. [Dept. of Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam (Netherlands); Stoop, Reinout [Dept. of Metabolic Health Research, TNO, P.O. Box 2215, 2301 CE Leiden (Netherlands); Toonder, Jaap M.J. den [Dept. of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Mulder, Lars [Dept. of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Zentner, Andrej [Dept. of Orthodontics, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam (Netherlands); Everts, Vincent [Dept. of Oral Cell Biology and Functional Anatomy, MOVE Research Institute, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Gustav Mahlerlaan 3004, 1081 LA Amsterdam (Netherlands)

2014-09-01

The role of mature collagen cross-links, pentosidine (Pen) cross-links in particular, in the micromechanical properties of cancellous bone is unknown. The aim of this study was to examine nonenzymatic glycation effects on tissue stiffness of demineralized and non-demineralized cancellous bone. A total of 60 bone samples were derived from mandibular condyles of six pigs, and assigned to either control or experimental groups. Experimental handling included incubation in phosphate buffered saline alone or with 0.2 M ribose at 37 °C for 15 days and, in some of the samples, subsequent complete demineralization of the sample surface using 8% EDTA. Before and after experimental handling, bone microarchitecture and tissue mineral density were examined by means of microcomputed tomography. After experimental handling, the collagen content and the number of Pen, hydroxylysylpyridinoline (HP), and lysylpyridinoline (LP) cross-links were estimated using HPLC, and tissue stiffness was assessed by means of nanoindentation. Ribose treatment caused an up to 300-fold increase in the number of Pen cross-links compared to nonribose-incubated controls, but did not affect the number of HP and LP cross-links. This increase in the number of Pen cross-links had no influence on tissue stiffness of both demineralized and nondemineralized bone samples. These findings suggest that Pen cross-links do not play a significant role in bone tissue stiffness. - Highlights: • The assessment of effects of glycation in bone using HPLC, microCT, and nanoindentation • Ribose incubation: 300‐fold increase in the number of pentosidine cross-links • 300‐fold increase in the number of pentosidine cross-links: no changes in bone tissue stiffness.

In vitro comparison of DE-QCT parameters with the compressive strength of cancellous bone

International Nuclear Information System (INIS)

Oravez, W.T.; Robertson, D.D.

1986-01-01

Quantitative computed tomography (QCT) is used as a method for assessing bone mineral in patients with osteoporosis. The implication being that if the mass of bone mineral is low enough then the patient is at risk for developing symptoms, i.e., fracture. The authors performed an in vitro test which compared dual-energy-QCT (DE-QCT) parameters with compressive strength. The bone samples were placed in a water bath and CT scanned using a Siemens DR-3. Alternating x-ray pulses of 125 and 85 kVp were used to generate the dual energy images. Four images, high kVp, low kVp, monoenergenic, and calcium equivalent, were reconstructed from each scan. A specially constructed bone mineral calibration phantom, consisting of a polyethylene rod and varying tubes of K2HP04, was placed within the water bath along with the specimens. Comparisons will be made between the various DE parameters and their relationship to the compressive strength of cancellous bone. The critical effect of trabecular bone orientation will also be discussed

78 FR 64254 - Advisory Committee for Education and Human Resources; Cancellation of Meeting

Science.gov (United States)

2013-10-28

... NATIONAL SCIENCE FOUNDATION Advisory Committee for Education and Human Resources; Cancellation of... Foundation is issuing this notice to cancel the November 6-7, 2013 Advisory Committee for Education and Human Resources meeting. The public notice for this committee was published in the Federal Register on October 3...

Molt performance and bone density of cortical, medullary, and cancellous bone in laying hens during feed restriction or alfalfa-based feed molt.

Science.gov (United States)

Kim, W K; Donalson, L M; Bloomfield, S A; Hogan, H A; Kubena, L F; Nisbet, D J; Ricke, S C

2007-09-01

A study was conducted to evaluate the effects of alfalfa-based molt diets on molting performance and bone qualities. A total of 36 Single Comb White Leghorn hens were used for the study. There were 6 treatments: pretrial control (PC), fully fed (FF), feed withdrawal (FW), 90% alfalfa:10% layer ration (A90), 80% alfalfa:20% layer ration (A80), and 70% alfalfa:30% layer ration (A70). For the PC treatment, hens were euthanized by CO(2) gas, and bones were collected before molt was initiated. At the end of the 9-d molt period, hens were euthanized, and femurs and tibias were collected to evaluate bone qualities by peripheral quantitative computed tomography, mechanical testing, and conventional ash weights. The hens fed alfalfa-based molt diets and FW stopped laying eggs within 5 d after molt started, and all hens in these groups had reduced ovary weights compared with those of the FF hens. In the FW and A90 groups, total femur volumetric bone mineral densities (vBMD) at the midshaft were significantly lower, but those of the A80 and A70 groups were not significantly different from the values for the PC and FF hens. In cortical bone density, the midshaft tibial vBMD were significantly higher for FF and A70 hens than for PC hens. The medullary bone densities at the midshaft femur or tibia of the FW, A90, A80, and A70 hens were reduced compared with those of the PC hens. Femur cancellous densities at the distal femur for the FW and A90 hens were significantly reduced compared with those of the PC and FF hens. The FW, A80, and A70 hens yielded significantly higher elastic moduli, and the A80 hens had higher ultimate stress compared with the PC hens, suggesting that the mechanical integrity of the midshaft bone was maintained even though the medullary vBMD was reduced. These results suggest that alfalfa-based molt diets exhibit molt performance similar to FW, that medullary and cancellous bones are labile bone compartments during molting, and that alfalfa-based molt diets

Glucocorticoid induced osteopenia in cancellous bone of sheep: validation of large animal model for spine fusion and biomaterial research

DEFF Research Database (Denmark)

Ding, Ming; Cheng, Liming; Bollen, Peter

2010-01-01

STUDY DESIGN: Glucocorticoid with low calcium and phosphorus intake induces osteopenia in cancellous bone of sheep. OBJECTIVE: To validate a large animal model for spine fusion and biomaterial research. SUMMARY OF BACKGROUND DATA: A variety of ovariectomized animals has been used to study...... osteoporosis. Most experimental spine fusions were based on normal animals, and there is a great need for suitable large animal models with adequate bone size that closely resemble osteoporosis in humans. METHODS: Eighteen female skeletal mature sheep were randomly allocated into 3 groups, 6 each. Group 1 (GC......-1) received prednisolone (GC) treatment (0.60 mg/kg/day, 5 times weekly) for 7 months. Group 2 (GC-2) received the same treatment as GC-1 for 7 months followed by 3 months without treatment. Group 3 was left untreated and served as the controls. All sheep received restricted diet with low calcium...

Biomechanical competence of six different bone screws for reconstructive surgery in three different transplants: Fibular, iliac crest, scapular and artificial bone.

Science.gov (United States)

Pietsch, Arnold P; Raith, Stefan; Ode, Jan-Eric; Teichmann, Jan; Lethaus, Bernd; Möhlhenrich, Stephan C; Hölzle, Frank; Duda, Georg N; Steiner, Timm

2016-06-01

The goal of this study was to determine a combination of screw and transplantation type that offers optimal primary stability for reconstructive surgery. Fibular, iliac crest, and scapular transplants were tested along with artificial bone substrate. Six different kinds of bone screws (Medartis(©)) were compared, each type utilized with one of six specimens from human transplants (n = 6). Controlled screw-in-tests were performed and the required torque was protocolled. Subsequently, pull-out-tests were executed to determine the retention forces. The artificial bone substitute material showed significantly higher retention forces than real bone samples. The self-drilling screws achieved the significantly highest retention values in the synthetic bone substitute material. Cancellous screws achieved the highest retention in the fibular transplants, while self-drilling and cancellous screws demonstrated better retention than cortical screws in the iliac crest. In the scapular graft, no significant differences were found between the screw types. In comparison to the human transplant types, the cortical screws showed the significantly highest values in the fibula and the lowest values in the iliac crest. The best retention was found in the combination of cancellous screws with fibular graft (514.8 N + -252.3 N). For the flat bones (i.e., scapular and illiac crest) we recommend the cancellous screws. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Estradiol-loaded PLGA nanoparticles for improving low bone mineral density of cancellous bone caused by osteoporosis: Application of enhanced charged nanoparticles with iontophoresis.

Science.gov (United States)

Takeuchi, Issei; Kobayashi, Shiori; Hida, Yukari; Makino, Kimiko

2017-07-01

Postmenopausal osteoporosis among older women, which occurs by an ovarian hormone deficiency, is one of the major public health problems. 17 β-estradiol (E2) is used to prevent and treat this disease as a drug of hormone replacement therapy. In oral administration, E2 is significantly affected by first-pass hepatic metabolism, and high dose administration must be needed to obtain drug efficacy. Therefore, alternative administration route is needed, and we have focused on the transdermal drug delivery system. In this study, we have prepared E2-loaded poly(DL-lactide-co-glycolide) (PLGA) nanoparticles for osteoporosis by using a combination of an antisolvent diffusion method with preferential solvation. The average particle diameter of the nanoparticles was 110.0±41.0nm and the surface charge number density was 82 times higher than that of conventional E2-loaded PLGA nanoparticles. Therapeutic evaluation of E2-loaded PLGA nanoparticles was carried out using ovariectomized female rats. Therapeutic efficacy was evaluated to measure bone mineral density of cancellous bone using an X-ray CT system. When the E2-loaded PLGA nanoparticles were administrated once a week, bone mineral density was significantly higher than that of the non-treated group at 60days after the start of treatment. Also, in the group administered this nanoparticle twice a week, the bone mineral density increased significantly at 45days after the start of treatment. From these results, it was revealed that E2-loaded PLGA nanoparticles with iontophoresis were useful to recover bone mineral density of cancellous bone, and it was also suggested that they extend the dosing interval of E2. Copyright © 2017 Elsevier B.V. All rights reserved.

Managment of frontal sinus fracture: obliteration sinus with cancellous bone graft.

Science.gov (United States)

Muminagic, Sahib; Masic, Tarik; Babajic, Emina; Asotic, Mithat

2011-01-01

Frontal sinus fractures make up about 2-15% of all facial fractures.This is relatively low frequency of occurrence, but it has a large potential of complication and may involve not only the frontal sinuse but more importantly the brain and the eyes. The management depends of the complexity. If anterior wall is fractured with grossly involved nasofrontal duct (NFD) in the injury it is paramount to occlude NFD. Very often, sinus obliteration is done at the same time. In our expirience autogenous cancellous bone graft is considered to be the best grafting material. It has the less short - or long-term complications and the donor site morbidity is insignificant.

Biomechanical study of the bone tissue with dental implants interaction

Directory of Open Access Journals (Sweden)

Navrátil P.

2011-12-01

Full Text Available The article deals with the stress-strain analysis of human mandible in the physiological state and after the dental implant application. The evaluation is focused on assessing of the cancellous bone tissue modeling-level. Three cancellous bone model-types are assessed: Non-trabecular model with homogenous isotropic material, nontrabecular model with inhomogeneous material obtained from computer tomography data using CT Data Analysis software, and trabecular model built from mandible section image. Computational modeling was chosen as the most suitable solution method and the solution on two-dimensional level was carried out. The results show that strain is more preferable value than stress in case of evaluation of mechanical response in cancellous bone. The non-trabecular model with CT-obtained material model is not acceptable for stress-strain analysis of the cancellous bone for singularities occurring on interfaces of regions with different values of modulus of elasticity.

Generating 3D tissue constructs with mesenchymal stem cells and a cancellous bone graft for orthopaedic applications

International Nuclear Information System (INIS)

Arca, Turkan; Genever, Paul; Proffitt, Joanne

2011-01-01

Bone matrix (BM) is an acellular crosslinked porcine-derived cancellous bone graft, and therefore may provide advantages over other synthetic and naturally derived materials for use in orthopaedic surgery. Here, we analysed the potential of BM to support the growth and differentiation of primary human multipotent stromal cells/mesenchymal stem cells (MSCs) in order to predict in vivo bone regeneration events. Imaging with laser scanning confocal microscopy and scanning electron microscopy showed that 1 day after static seeding, a dense population of viable MSCs could be achieved on scaffolds suggesting they could be used for in vivo delivery of cells to the implant site. Long-term growth analysis by confocal imaging and histology demonstrated that BM was permissive to the growth and the 3D population of primary MSCs and an enhanced green fluorescent protein expressing osteosarcoma cell line, eGFP.MG63s, over several days in culture. Measurement of alkaline phosphatase (ALP) activities and mRNA expression levels of osteogenic markers (Runx-2, ALP, collagen type I, osteonectin, osteocalcin and osteopontin) indicated that BM supported osteogenesis of MSCs when supplemented with osteogenic stimulants. Upregulation of some of these osteogenic markers on BM, but not on tissue culture plastic, under non-osteogenic conditions suggested that BM also had osteoinductive capacities.

Generating 3D tissue constructs with mesenchymal stem cells and a cancellous bone graft for orthopaedic applications

Energy Technology Data Exchange (ETDEWEB)

Arca, Turkan; Genever, Paul [Department of Biology, University of York, York, YO10 5DD (United Kingdom); Proffitt, Joanne, E-mail: paul.genever@york.ac.uk [TSL Centre of Biologics, Covidien, Allerton Bywater, Castleford, WF10 2DB (United Kingdom)

2011-04-15

Bone matrix (BM) is an acellular crosslinked porcine-derived cancellous bone graft, and therefore may provide advantages over other synthetic and naturally derived materials for use in orthopaedic surgery. Here, we analysed the potential of BM to support the growth and differentiation of primary human multipotent stromal cells/mesenchymal stem cells (MSCs) in order to predict in vivo bone regeneration events. Imaging with laser scanning confocal microscopy and scanning electron microscopy showed that 1 day after static seeding, a dense population of viable MSCs could be achieved on scaffolds suggesting they could be used for in vivo delivery of cells to the implant site. Long-term growth analysis by confocal imaging and histology demonstrated that BM was permissive to the growth and the 3D population of primary MSCs and an enhanced green fluorescent protein expressing osteosarcoma cell line, eGFP.MG63s, over several days in culture. Measurement of alkaline phosphatase (ALP) activities and mRNA expression levels of osteogenic markers (Runx-2, ALP, collagen type I, osteonectin, osteocalcin and osteopontin) indicated that BM supported osteogenesis of MSCs when supplemented with osteogenic stimulants. Upregulation of some of these osteogenic markers on BM, but not on tissue culture plastic, under non-osteogenic conditions suggested that BM also had osteoinductive capacities.

Assessment of cancellous bone mechanical properties from micro-FE models based on micro-CT, pQCT and MR images.

NARCIS (Netherlands)

Rietbergen, van B.; Majumdar, S.; Pistoia, W.; Newitt, D.C.; Kothari, M.; Laib, A.; Rüegsegger, P.

1998-01-01

Recently, new micro-finite element (micro-FE) techniques have been introduced to calculate cancellous bone mechanical properties directly from high-resolution images of its internal architecture. Also recently, new peripheral quantitative computed tomography (pQCT) and magnetic resonance (MR)

脱蛋白松质骨作为异种骨移植材料的修复作用%Repair effect of deproteinised cancellous bone as xenogeneic bone graft material

Institute of Scientific and Technical Information of China (English)

高春阳; 姜宏春; 金春明

2011-01-01

BACKGROUND: Unequal size, mutual communication, and open pore network structure can be seen in cancellous bone treated with deproteinization. Its inorganic component is hydroxyapatite, and the organic component is collagen, which has a good mechanical property and biocompatibility. It may be a new type of bone graft material.OBJECTIVE: To study the properties of xenogeneic deproteinised cancellous bone being carrier of bone tissue engineering in bone fusion.METHODS: Taking “xenogeneic deproteinised cancellous bone, bone fusion, carrier” in Chinese as search terms, the articles from January 1998 to December 2009 in VIP database, CNKI database, Pubmed database were retrieved by computer. The relevant literatures were included, the literature of irrelevant purpose and repetitive content were excluded, and 33 of them were involved for further analysis.RESULTS AND CONCLUSION: Compared with synthetic bone material, animal bones have similar biomaterial structure, modeling, excellent cell attachment, and cell growth and proliferation environment. However, the compatibility of bone tissue is poor, because of the differences in species when xenogeneic deproteinised cancellous bone transplantation, and gravis immune rejection, the key question is implantation of immune problems. How to overcome immunogenicity, xenogeneic deproteinised cancellous bone is a good carrier of bone tissue engineering, which can provide a stable environment for revascularization and differentiation of osteoblasts.%背景:采用脱蛋白处理后的松质骨可见大小不等、相互交通、开放孔隙的网架结构,其无机成分为羟基磷灰石,有机成分为胶原,力学性能保存良好,有良好的细胞相容性,可能是一种新型骨移�

Measurement of microvascular blood flow in cancellous bone using laser Doppler flowmetry and 133Xe-clearance

International Nuclear Information System (INIS)

Hellem, S.; Jacobsson, L.S.; Nilsson, G.E.; Lewis, D.H.

1983-01-01

Blood flow in cancelleous bone with varying vascular density was investigated simultaneously with Laser Doppler Flowmeter (LDF) and 113 Xe-clearance. The cancellous bone subapical to 2 contralateral incisors in the mandibles of 17 young pigs was used as an experimental model. Light from a 2 mW He-Ne-laser was guided through an optical fibre to a flowmeter probe. Stainless steel probe-holders firmly inserted in the pulpal canals of the two incisors served as the probe entrance to cancellous bone for blood flow recording. Due to the Doppler effect, the light scattered by circulating blood cells undergoes a frequency shift. The back-scattered light picked up by optical fibres in the probe, was guided to a photosensitive device, where it was demodulated. After signal processing, a signal referred to as the Blood Flow Value (BFV) was recorded on a pen recorder. Rhythmical variations (vasomotion) in BFV with frequencies from 2-11 cycles/min were observed in 6% of recordings made initially after probeholder implantation, and in 34% of the recordings made 5 weeks later. On this occasion, a marked increase in BFV was recorded. Histological examination showed increased vascularity in the bone tissue. The reproducibility error of LDF was 7.4% and temporal changes in BFV, apart from vasomotion, were 8.3%, provided no injections or manipulations of the probe were made. Spatial variations in BFV were found to be related to the vascular density. 2 successive recordings by LDF from the same bone area were highly correlated (r=0.98). The corresponding figure for 2 logarithmic decay rates of locally injected 133 Xe was 0.76. No correlation between BFV and 133 Xe-clearance could be demonstrated. (author)

Evaluation of the bone microstructures after the mandibular reconstruction, using bioresorbable hydroxyapatite/poly-L-lactide mesh tray and the particulate cancellous bone

International Nuclear Information System (INIS)

Takahashi, Hidetoshi; Matsuo, Akira; Chiba, Hiroshige

2010-01-01

The combination of particulate cancellous bone and marrow (PCBM) and a titanium tray is frequently used for mandibular reconstruction. However, there are difficulties in bending the tray and forming a suitable contour. In addition, the metallic ions elute into the living body and the hinders the implant insertion; therefore, a removable operation is required after reconstruction. Hydroxyapatite/poly-L-lactide (HA/PLLA) is a bone-bonding material that has both bio-activity and bio-resorbability. It may overcome the weakness of a titanium tray, but the bone microstructures have not been evaluated after the use of this tray for PCBM reconstruction. We created defects on the mandible of a beagle and reconstructed it by filling it with a mixture of PCBM and PRP using the HA/PLLA tray. We examined the bone-formation mechanism using a confocal laser microscope and bone microstructural analysis using microCT. As a result, compared to the titanium tray, the bone-formation is delayed during the first 3 to 6 months with an HA/PLLA tray. However, a formation of new bone with equal quality is observed after 12 months. According to the bone microstructural measurement, both of them had higher bone volume fraction than the native bone but other parameters were the same. From the above, the quantity of the new bone in the HA/PLLA tray is the same as the bone in the titanium tray, and has equal bone microstructures with the surrounding native bone. (author)

Oreopithecus was a bipedal ape after all: Evidence from the iliac cancellous architecture

Science.gov (United States)

Rook, Lorenzo; Bondioli, Luca; Köhler, Meike; Moyà-Solà, Salvador; Macchiarelli, Roberto

1999-01-01

Textural properties and functional morphology of the hip bone cancellous network of Oreopithecus bambolii, a 9- to 7-million-year-old Late Miocene hominoid from Italy, provide insights into the postural and locomotor behavior of this fossil ape. Digital image processing of calibrated hip bone radiographs reveals the occurrence of trabecular features, which, in humans and fossil hominids, are related to vertical support of the body weight, i.e., to bipedality. PMID:10411955

Cross-correlative 3D micro-structural investigation of human bone processed into bone allografts

International Nuclear Information System (INIS)

Singh, Atul Kumar; Gajiwala, Astrid Lobo; Rai, Ratan Kumar; Khan, Mohd Parvez; Singh, Chandan; Barbhuyan, Tarun; Vijayalakshmi, S.; Chattopadhyay, Naibedya; Sinha, Neeraj; Kumar, Ashutosh; Bellare, Jayesh R.

2016-01-01

critical parameters of bone, showing a significant advancements over currently existing methods. - Highlights: • Aim: to analyze three-dimensional micro- and macro-structural changes in normal and osteoporotic human bone processed into allografts for transplantation. • Method: ssNMR, SEM, μCT-MIMICS and TGA were used for delineating the ultra-structural property of cortical and cancellous bone. • Findings: Altered balance in water content and association, collagen tertiary structure, and crystalline order in normal and osteoporotic bone (ssNMR). • Pasteurization, alcohol treatment and radiation affect bone through bound water integrity resulting in shifted HU (μCT-MIMICS®), which could make bone weaker. • Cross-correlation between probes used quantitatively demonstrated that protocol adopted for bone processing could play a crucial role in allograft preparation.

Cross-correlative 3D micro-structural investigation of human bone processed into bone allografts

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Singh, Atul Kumar [Centre for Research in Nanotechnology & Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Gajiwala, Astrid Lobo [Tissue Bank, Tata Memorial Hospital, Parel, Mumbai 400012 (India); Rai, Ratan Kumar [Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014 (India); Khan, Mohd Parvez [Division of Endocrinology, Center for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI) CSIR-Central Drug Research Institute, Lucknow 226031 (India); Singh, Chandan [Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014 (India); Barbhuyan, Tarun [Division of Endocrinology, Center for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI) CSIR-Central Drug Research Institute, Lucknow 226031 (India); Vijayalakshmi, S. [Centre for Research in Nanotechnology & Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Chattopadhyay, Naibedya [Division of Endocrinology, Center for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI) CSIR-Central Drug Research Institute, Lucknow 226031 (India); Sinha, Neeraj, E-mail: neerajcbmr@gmail.com [Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014 (India); Kumar, Ashutosh, E-mail: ashutoshk@iitb.ac.in [Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); Bellare, Jayesh R., E-mail: jb@iitb.ac.in [Centre for Research in Nanotechnology & Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India)

2016-05-01

critical parameters of bone, showing a significant advancements over currently existing methods. - Highlights: • Aim: to analyze three-dimensional micro- and macro-structural changes in normal and osteoporotic human bone processed into allografts for transplantation. • Method: ssNMR, SEM, μCT-MIMICS and TGA were used for delineating the ultra-structural property of cortical and cancellous bone. • Findings: Altered balance in water content and association, collagen tertiary structure, and crystalline order in normal and osteoporotic bone (ssNMR). • Pasteurization, alcohol treatment and radiation affect bone through bound water integrity resulting in shifted HU (μCT-MIMICS®), which could make bone weaker. • Cross-correlation between probes used quantitatively demonstrated that protocol adopted for bone processing could play a crucial role in allograft preparation.

Morphological studies at subchondral bone structures in human early arthrosis. Final report

International Nuclear Information System (INIS)

1992-01-01

Quantitative histomorphometric studies using an image analysis system were performed simultaneously on hyaline cartilage, calcified cartilage and subchondral cancellous bone of human tibial heads for detailed information about the pathogenesis of arthrosis. Joint structures need to be fully detected in three dimensions since measurement values are more affected by topographical aspects than by either age, or sex, or arthrosin stage. Mechanical factors were found to affect essentially the initiation and progression of arthrosis. Results are demonstrated in detail. (orig.) [de

A soluble activin type IIA receptor mitigates the loss of femoral neck bone strength and cancellous bone mass in a mouse model of disuse osteopenia.

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Lodberg, Andreas; Eijken, Marco; van der Eerden, Bram C J; Okkels, Mette Wendelboe; Thomsen, Jesper Skovhus; Brüel, Annemarie

2018-05-01

Disuse causes a rapid and substantial bone loss distinct in its pathophysiology from the bone loss associated with cancers, age, and menopause. While inhibitors of the activin-receptor signaling pathway (IASPs) have been shown to prevent ovariectomy- and cancer-induced bone loss, their application in a model of disuse osteopenia remains to be tested. Here, we show that a soluble activin type IIA receptor (ActRIIA-mFc) increases diaphyseal bone strength and cancellous bone mass, and mitigates the loss of femoral neck bone strength in the Botulinum Toxin A (BTX)-model of disuse osteopenia in female C57BL/6J mice. We show that ActRIIA-mFc treatment preferentially stimulates a dual-effect (anabolic-antiresorptive) on the periosteal envelope of diaphyseal bone, demonstrating in detail the effects of ActRIIA-mFc on cortical bone. These observations constitute a previously undescribed feature of IASPs that mediates at least part of their ability to mitigate detrimental effects of unloading on bone tissue. The study findings support the application of IASPs as a strategy to combat bone loss during disuse. Copyright © 2018 Elsevier Inc. All rights reserved.

The development of a composite bone model for training on placement of dental implants.

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Alkhodary, Mohamed Ahmed; Abdelraheim, Abdelraheim Emad Eldin; Elsantawy, Abd Elaleem Hassan; Al Dahman, Yousef Hamad; Al-Mershed, Mohammed

2015-04-01

It takes a lot of training on patients for both undergraduate to develop clinical sense as regards to the placement of dental implants in the jaw bones, also, the models provided by the dental implant companies for training are usually made of strengthened synthetic foams, which are far from the composition, and tactile sense provided by natural bone during drilling for clinical placement of dental implants. This is an in-vitro experimental study which utilized bovine femur bone, where the shaft of the femur provided the surface compact layer, and the head provided the cancellous bone layer, to provide a training model similar to jaw bones macroscopic anatomy. Both the compact and cancellous bone samples were characterized using mechanical compressive testing. The elastic moduli of the cancellous and cortical femur bone were comparable to those of the human mandible, and the prepared training model provided a more lifelike condition during the drilling and placement of dental implants. The composite bone model developed simulated the macroscopic anatomy of the jaw bones having a surface layer of compact bone, and a core of cancellous bone, and provided a better and a more natural hands-on experience for placement of dental implants as compared to plastic models made of polyurethane.

Contribution of the endosteal surface of cortical bone to the trabecular pattern seen on IOPA radiographs: an in vitro study

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P T Ravikumar

2012-01-01

Full Text Available Objectives: A study was conducted to assess the contribution of the cancellous and endosteal surface of the cortical bone to the trabecular pattern seen in an IOPA radiograph. Materials and methods: An in vitro study analyzing the contribution of the endosteal surface of cortical bone and cancellous bone to the trabecular pattern was conducted, using 60 specimens of desiccated human mandibles. The mode of execution involved IOPA radiographic evaluation of premolarmolar segments in the specimens before and after removal of cancellous bone. The radiographs were numbered for identification and subjected to evaluation by 5 dentomaxillofacial radiologists who were doubleblinded to ensure an unbiased interpretation. Results: The trabecular pattern appreciation by the experts in the IOPA radiographs before and after removal of cancellous bone displayed immaculate correlation as per the Goodman-Kruskal Gamma Coefficient values which was 0.78 indicating a very large correlation. The relative density of trabecular pattern was significantly higher in radiograph before than after removal of cancellous bone with p-value less than 0.05. Conclusion: Based on these results it was adjudged that both the cancellous and endosteal surface of cortical bone contributed significantly to the trabecular pattern in an IOPA radiograph.

Clinical uses of radiosterilized freeze-dried human bone: its application in buccomaxillary surgery

International Nuclear Information System (INIS)

Wolfsohn, B.; Taramasso, F.; Godoy, J.; Wodowoz, O.; Saldias, M.; Silva, W.; Machin, D.; Sanchez, G.; Alvarez, I.

2008-01-01

Full text: The objective of this paper is to evaluate the uses of different human bone tissue allografts in bucomaxillary surgery between 2005 and 2007. Presentation of our experience using single freeze dried bone allografts and associated to bovine collagen membranes (commercial registered). Twenty patients were treated with cortical struts, cancellous chips, morsellized and morsellized demineralized bone. All the grafts were processed at the INDT multi tissue bank from cardiac arrest and brain death cadaveric donors. All the tissues were radiosterilized by Gamma radiation. Bone allografts were used: 1) to optimize bone support increasing maxillar or mandible bone before implant surgery. 2) in dehiscences and fissures during the implant surgery. 3) to stimulate bone regeneration in alveolar cavity, post-apicectomies, and cystectomies as well as for bone defects. The patients were periodically evaluated using standardized protocols. All the cases were successful showing clinic and radiologically osseointegration after 6 and 12 months. Results were evaluated considering surgical technique and patients bucomaxillary rehabilitation. Clinical uses of bone allografts confirm in our experience, as scientific literature outcomes shows, are useful in patients that refuses autografts ablation. (Author)

Breast Cancer Cell Colonization of the Human Bone Marrow Adipose Tissue Niche.

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Templeton, Zach S; Lie, Wen-Rong; Wang, Weiqi; Rosenberg-Hasson, Yael; Alluri, Rajiv V; Tamaresis, John S; Bachmann, Michael H; Lee, Kitty; Maloney, William J; Contag, Christopher H; King, Bonnie L

2015-12-01

Bone is a preferred site of breast cancer metastasis, suggesting the presence of tissue-specific features that attract and promote the outgrowth of breast cancer cells. We sought to identify parameters of human bone tissue associated with breast cancer cell osteotropism and colonization in the metastatic niche. Migration and colonization patterns of MDA-MB-231-fLuc-EGFP (luciferase-enhanced green fluorescence protein) and MCF-7-fLuc-EGFP breast cancer cells were studied in co-culture with cancellous bone tissue fragments isolated from 14 hip arthroplasties. Breast cancer cell migration into tissues and toward tissue-conditioned medium was measured in Transwell migration chambers using bioluminescence imaging and analyzed as a function of secreted factors measured by multiplex immunoassay. Patterns of breast cancer cell colonization were evaluated with fluorescence microscopy and immunohistochemistry. Enhanced MDA-MB-231-fLuc-EGFP breast cancer cell migration to bone-conditioned versus control medium was observed in 12/14 specimens (P = .0014) and correlated significantly with increasing levels of the adipokines/cytokines leptin (P = .006) and IL-1β (P = .001) in univariate and multivariate regression analyses. Fluorescence microscopy and immunohistochemistry of fragments underscored the extreme adiposity of adult human bone tissues and revealed extensive breast cancer cell colonization within the marrow adipose tissue compartment. Our results show that breast cancer cells migrate to human bone tissue-conditioned medium in association with increasing levels of leptin and IL-1β, and colonize the bone marrow adipose tissue compartment of cultured fragments. Bone marrow adipose tissue and its molecular signals may be important but understudied components of the breast cancer metastatic niche. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Evidence for reduced cancellous bone mass in the spontaneously hypertensive rat

Science.gov (United States)

Wang, T. M.; Hsu, J. F.; Jee, W. S.; Matthews, J. L.

1993-01-01

The histomorphometric changes in the proximal tibial metaphysis and epiphyseal growth plate and midtibial shaft of 26-week-old spontaneously hypertensive rats (SHR) compared with those of the corresponding normotensive Wistar-Kyoto (WKY) rats were studied. A decrease in body weight, growth plate thickness, and longitudinal growth rate of the proximal tibial epiphysis, trabecular bone volume, trabecular thickness and number, the number of osteoblasts and osteoprogenitor cells per millimeter square surface of the proximal tibial metaphysis, periosteal and endocortical apposition rate and bone formation rate of the tibial diaphysis were observed in the SHR. Additionally, systolic blood pressure, the number of osteoclasts per millimeter square surface and average number of nuclei per osteoclast of the proximal tibial metaphysis were significantly increased. Thus, osteoclastic activity is dominant over osteoblastic and chondroblastic activity in the SHR that results in a cancellous bone deficit in the skeleton. It will require additional work to ascertain the underlying cause for this condition as several factors in the SHR with a potential for causing this change are present, including elevated parathyroid hormone (PTH), depressed 1,25-(OH)2D3, low calcium absorption, reduced body weight (reduced loading) elevated blood pressure and possibly other direct cell differences in the mutant strain. At present elevated PTH and adaptation to underloading from reduced weight are postulated to be a likely cause, but additional studies are required to test this interpretation.

Human stem cell osteoblastogenesis mediated by novel glycogen synthase kinase 3 inhibitors induces bone formation and a unique bone turnover biomarker profile in rats

International Nuclear Information System (INIS)

Gilmour, Peter S.; O'Shea, Patrick J.; Fagura, Malbinder; Pilling, James E.; Sanganee, Hitesh; Wada, Hiroki; Courtney, Paul F.; Kavanagh, Stefan; Hall, Peter A.; Escott, K. Jane

2013-01-01

Wnt activation by inhibiting glycogen synthase kinase 3 (GSK-3) causes bone anabolism in rodents making GSK-3 a potential therapeutic target for osteoporotic and osteolytic metastatic bone disease. To understand the wnt pathway related to human disease translation, the ability of 3 potent inhibitors of GSK-3 (AZD2858, AR79, AZ13282107) to 1) drive osteoblast differentiation and mineralisation using human adipose-derived stem cells (hADSC) in vitro; and 2) stimulate rat bone formation in vivo was investigated. Bone anabolism/resorption was determined using clinically relevant serum biomarkers as indicators of bone turnover and bone formation assessed in femurs by histopathology and pQCT/μCT imaging. GSK-3 inhibitors caused β-catenin stabilisation in human and rat mesenchymal stem cells, stimulated hADSC commitment towards osteoblasts and osteogenic mineralisation in vitro. AZD2858 produced time-dependent changes in serum bone turnover biomarkers and increased bone mass over 28 days exposure in rats. After 7 days, AZD2858, AR79 or AZ13282107 exposure increased the bone formation biomarker P1NP, and reduced the resorption biomarker TRAcP-5b, indicating increased bone anabolism and reduced resorption in rats. This biomarker profile was differentiated from anabolic agent PTH 1–34 or the anti-resorptive Alendronate-induced changes. Increased bone formation in cortical and cancellous bone as assessed by femur histopathology supported biomarker changes. 14 day AR79 treatment increased bone mineral density and trabecular thickness, and decreased trabecular number and connectivity assessed by pQCT/μCT. GSK-3 inhibition caused hADSC osteoblastogenesis and mineralisation in vitro. Increased femur bone mass associated with changes in bone turnover biomarkers confirmed in vivo bone formation and indicated uncoupling of bone formation and resorption. - Highlights: • Wnt modulation with 3 novel GSK-3 inhibitors alters bone growth. • Human stem cell osteoblastogenesis and

Laterality and grip strength influence hand bone micro-architecture in modern humans, an HRpQCT study.

Science.gov (United States)

Reina, Nicolas; Cavaignac, Etienne; Trousdale, William H; Laffosse, Jean-Michel; Braga, José

2017-06-01

It is widely hypothesized that mechanical loading, specifically repetitive low-intensity tasks, influences the inner structure of cancellous bone. As such, there is likely a relationship between handedness and bone morphology. The aim of this study is to determine patterns in trabecular bone between dominant and non-dominant hands in modern humans. Seventeen healthy patients between 22 and 32 years old were included in the study. Radial carpal bones (lunate, capitate, scaphoid, trapezium, trapezoid, 1st, 2nd and 3rd metacarpals) were analyzed with high-resolution micro-computed tomography. Additionally, crush and pinch grip were recorded. Factorial analysis indicated that bone volume ratio, trabeculae number (Tb.N), bone surface to volume ratio (BS.BV), body weight, stature and crush grip were all positively correlated with principal components 1 and 2 explaining 78.7% of the variance. Volumetric and trabecular endostructural parameters (BV/TV, BS/BV or Tb.Th, Tb.N) explain the observed inter-individual variability better than anthropometric or clinical parameters. Factors analysis regressions showed correlations between these parameters and the dominant side for crush strength for the lunate (r 2 = 0.640, P modern human wrist. © 2017 Anatomical Society.

Effect of ovariectomy on BMD, micro-architecture and biomechanics of cortical and cancellous bones in a sheep model.

Science.gov (United States)

Wu, Zi-xiang; Lei, Wei; Hu, Yun-yu; Wang, Hai-qiang; Wan, Shi-yong; Ma, Zhen-sheng; Sang, Hong-xun; Fu, Suo-chao; Han, Yi-sheng

2008-11-01

Osteoporotic/osteopenia fractures occur most frequently in trabeculae-rich skeletal sites. The purpose of this study was to use a high-resolution micro-computed tomography (micro-CT) and dual energy X-ray absorptionmeter (DEXA) to investigate the changes in micro-architecture and bone mineral density (BMD) in a sheep model resulted from ovariectomy (OVX). Biomechanical tests were performed to evaluate the strength of the trabecular bone. Twenty adult sheeps were randomly divided into three groups: sham group (n=8), group 1 (n=4) and group 2 (n=8). In groups 1 and 2, all sheep were ovariectomized (OVX); in the sham group, the ovaries were located and the oviducts were ligated. In all animals, BMD for lumbar spine was obtained during the surgical procedure. BMD at the spine, femoral neck and femoral condyle was determined 6 months (group 1) and 12 months (group 2) post-OVX. Lumbar spines and femora were obtained and underwent BMD scan, micro-CT analysis. Compressive mechanical properties were determined from biopsies of vertebral bodies and femoral condyles. BMD, micro-architectural parameters and mechanical properties of cancellous bone did not decrease significantly at 6 months post-OVX. Twelve months after OVX, BMD, micro-architectural parameters and mechanical properties decreased significantly. The results of linear regression analyses showed that trabecular thickness (Tb.Th) (r=0.945, R2=0.886) and bone volume fraction (BV/TV) (r=0.783, R2=0.586) had strong (R2>0.5) correlation to compression stress. In OVX sheep, changes in the structural parameters of trabecular bone are comparable to the human situation during osteoporosis was induced. The sheep model presented seems to meet the criteria for an osteopenia model for fracture treatment with respect to morphometric and mechanical properties. But the duration of OVX must be longer than 12 months to ensure the animal model can be established successfully.

Evaluation of the effect of platelet rich plasma (PRP) on enhancement of bone healing in diaphyseal bone defects by radiography and computed tomography

International Nuclear Information System (INIS)

Özak, Ahmet; Yardimci, Cenk; Nİsbet, Özlem H.; Bayrak, İlkay Koray; Nİsbet, Cevat

2010-01-01

The effect of platelet-rich plasma (PRP) with autogenous cancellous bone graft on enhancement of bone healing in diaphyseal bone defects was evaluated. A 4-mm defect was created in the middiaphysis of the tibias of 20 rabbits. Rabbits were divided into two groups of ten animals each: only autogenous cancellous graft, PRP and autogenous cancellous graft. In animals of group 1, only autogenous cancellous grafts, and to those in group 2, PRP and autogenous cancellous grafts, were applied to the defect. Radiographical and computed tomography (CT) views were taken and evaluated on postoperative days 0, 15, 30, 60, and 90. According to the bone formation, union, and remodeling scores, group 1 had better scores than group 2 on days 30, 60, and 90. The density was significantly increased on day 60 than on days 0, 15, and 30 in group 1. In conclusion, it was evaluated that PRP could not enhance the bone regeneration in diaphyseal defects when used with autogenous cancellous bone graft

Human stem cell osteoblastogenesis mediated by novel glycogen synthase kinase 3 inhibitors induces bone formation and a unique bone turnover biomarker profile in rats

Energy Technology Data Exchange (ETDEWEB)

Gilmour, Peter S., E-mail: Peter.Gilmour@astrazeneca.com [New Opportunities Innovative Medicines group, AstraZeneca R and D, Alderley Park, Cheshire SK10 4TF (United Kingdom); O' Shea, Patrick J.; Fagura, Malbinder [New Opportunities Innovative Medicines group, AstraZeneca R and D, Alderley Park, Cheshire SK10 4TF (United Kingdom); Pilling, James E. [Discovery Sciences, AstraZeneca R and D, Alderley Park, Cheshire SK10 4TF (United Kingdom); Sanganee, Hitesh [New Opportunities Innovative Medicines group, AstraZeneca R and D, Alderley Park, Cheshire SK10 4TF (United Kingdom); Wada, Hiroki [R and I IMed, AstraZeneca R and D, Molndal (Sweden); Courtney, Paul F. [DMPK, AstraZeneca R and D, Alderley Park, Cheshire SK10 4TF (United Kingdom); Kavanagh, Stefan; Hall, Peter A. [Safety Assessment, AstraZeneca R and D, Alderley Park, Cheshire SK10 4TF (United Kingdom); Escott, K. Jane [New Opportunities Innovative Medicines group, AstraZeneca R and D, Alderley Park, Cheshire SK10 4TF (United Kingdom)

2013-10-15

Wnt activation by inhibiting glycogen synthase kinase 3 (GSK-3) causes bone anabolism in rodents making GSK-3 a potential therapeutic target for osteoporotic and osteolytic metastatic bone disease. To understand the wnt pathway related to human disease translation, the ability of 3 potent inhibitors of GSK-3 (AZD2858, AR79, AZ13282107) to 1) drive osteoblast differentiation and mineralisation using human adipose-derived stem cells (hADSC) in vitro; and 2) stimulate rat bone formation in vivo was investigated. Bone anabolism/resorption was determined using clinically relevant serum biomarkers as indicators of bone turnover and bone formation assessed in femurs by histopathology and pQCT/μCT imaging. GSK-3 inhibitors caused β-catenin stabilisation in human and rat mesenchymal stem cells, stimulated hADSC commitment towards osteoblasts and osteogenic mineralisation in vitro. AZD2858 produced time-dependent changes in serum bone turnover biomarkers and increased bone mass over 28 days exposure in rats. After 7 days, AZD2858, AR79 or AZ13282107 exposure increased the bone formation biomarker P1NP, and reduced the resorption biomarker TRAcP-5b, indicating increased bone anabolism and reduced resorption in rats. This biomarker profile was differentiated from anabolic agent PTH{sub 1–34} or the anti-resorptive Alendronate-induced changes. Increased bone formation in cortical and cancellous bone as assessed by femur histopathology supported biomarker changes. 14 day AR79 treatment increased bone mineral density and trabecular thickness, and decreased trabecular number and connectivity assessed by pQCT/μCT. GSK-3 inhibition caused hADSC osteoblastogenesis and mineralisation in vitro. Increased femur bone mass associated with changes in bone turnover biomarkers confirmed in vivo bone formation and indicated uncoupling of bone formation and resorption. - Highlights: • Wnt modulation with 3 novel GSK-3 inhibitors alters bone growth. • Human stem cell osteoblastogenesis

The Mechanics of Long Bone Fractures.

Science.gov (United States)

1981-01-31

r = .99) between wet density and ultimate bending strength for 37 specimens of human femoral bone. Evans (1973) studied embalmed human tibial...Work 2 2.2 Methods 6 2.2.1 Torsional Loading 6 2.2.2 The Effects of Combined Loading 10 2.2.3 Cancellous Bone Effects 11 2.3 Results 11 2.3.1...PROPERTIES 21 3.1 Previous Work 22 3.2 Methods 26 3.2.1 Cross Sectional Property Software 26 3.2.2 CT Scanning Procedure 28 3.2.3 Linear Dependency of

Recombinant human bone morphogenetic protein induces bone formation

International Nuclear Information System (INIS)

Wang, E.A.; Rosen, V.; D'Alessandro, J.S.; Bauduy, M.; Cordes, P.; Harada, T.; Israel, D.I.; Hewick, R.M.; Kerns, K.M.; LaPan, P.; Luxenberg, D.P.; McQuaid, D.; Moutsatsos, I.K.; Nove, J.; Wozney, J.M.

1990-01-01

The authors have purified and characterized active recombinant human bone morphogenetic protein (BMP) 2A. Implantation of the recombinant protein in rats showed that a single BMP can induce bone formation in vivo. A dose-response and time-course study using the rat ectopic bone formation assay revealed that implantation of 0.5-115 μg of partially purified recombinant human BMP-2A resulted in cartilage by day 7 and bone formation by day 14. The time at which bone formation occurred was dependent on the amount of BMP-2A implanted; at high doses bone formation could be observed at 5 days. The cartilage- and bone-inductive activity of the recombinant BMP-2A is histologically indistinguishable from that of bone extracts. Thus, recombinant BMP-2A has therapeutic potential to promote de novo bone formation in humans

Effects of growth hormone and low dose estrogen on bone growth and turnover in long bones of hypophysectomized rats

Science.gov (United States)

Kidder, L. S.; Schmidt, I. U.; Evans, G. L.; Turner, R. T.

1997-01-01

Pituitary hormones are recognized as critical to longitudinal growth, but their role in the radial growth of bone and in maintaining cancellous bone balance are less clear. This investigation examines the histomorphometric effects of hypophysectomy (Hx) and ovariectomy (OVX) and the subsequent replacement of growth hormone (GH) and estrogen (E), in order to determine the effects and possible interactions between these two hormones on cortical and cancellous bone growth and turnover. The replacement of estrogen is of interest since Hx results in both pituitary and gonadal hormone insufficiencies, with the latter being caused by the Hx-associated reduction in follicle stimulating hormone (FSH). All hypophysectomized animals received daily supplements of hydrocortisone (500 microg/kg) and L-thyroxine (10 microg/kg), whereas intact animals received daily saline injections. One week following surgery, hypophysectomized animals received either daily injections of low-dose 17 beta-estradiol (4.8 microg/kg s.c.), 3 X/d recombinant human GH (2 U/kg s.c.), both, or saline for a period of two weeks. Flurochromes were administered at weekly intervals to label bone matrix undergoing mineralization. Whereas Hx resulted in reductions in body weight, uterine weight, and tibial length, OVX significantly increased body weight and tibial length, while reducing uterine weight. The combination of OVX and Hx resulted in values similar to Hx alone. Treatment with GH normalized body weight and bone length, while not affecting uterine weight in hypophysectomized animals. Estrogen increased uterine weight, while not impacting longitudinal bone growth and reduced body weight. Hypophysectomy diminished tibial cortical bone area through reductions in both mineral appositional rate (MAR) and bone formation rate (BFR). While E had no effect, GH increased both MAR and BFR, though not to sham-operated (control) levels. Hypophysectomy reduced proximal tibial trabecular number and cancellous bone

Horizontal Bone Reconstruction on sites with different amounts of native bone: a retrospective study

Directory of Open Access Journals (Sweden)

André Antonio Pelegrine

2018-04-01

Full Text Available Abstract: The lack of guidelines for bone augmentation procedures might compromise decision making in implantology. The objective of this study was to perform a retrospective study to verify the outcomes of horizontal bone reconstruction in implant dentistry with different types of materials and amounts of native bone in the recipient bed to allow for a new guideline for horizontal bone reconstruction. One hundred preoperative CT scans were retrospectively evaluated and categorized in accordance to horizontal bone defects as presence (Group P or absence (Group A of cancellous bone in the recipient bed. Different approaches were used to treat the edentulous ridge and the outcomes were defined either as satisfactory or unsatisfactory regarding the possibility of implant placement. The percentage distribution of the patients according to the presence or absence of cancellous bone was 92% for Group P and 8% for Group A. In Group P, 98% of the patients had satisfactory outcomes, and the use of autografts had 100% of satisfactory outcomes in this group. In Group A, 37.5% of the patients had satisfactory outcomes, and the use of autografts also yielded 100% of satisfactory outcomes. The use of allografts and xenografts in Group A had 0% and 33.3% of satisfactory outcomes, respectively. Therefore, it seems reasonable to speculate that the presence of cancellous bone might be predictive and predictable when the decision includes bone substitutes. In cases of absence of cancellous bone in the recipient bed, the use of a vitalized graft seems to be mandatory.

The variation of cancellous bones at lumbar vertebra, femoral neck, mandibular angle and rib in ovariectomized sheep.

Science.gov (United States)

Zhang, Yongqiang; Li, Yongfeng; Gao, Qi; Shao, Bo; Xiao, Jianrui; Zhou, Hong; Niu, Qiang; Shen, Mingming; Liu, Baolin; Hu, Kaijin; Kong, Liang

2014-07-01

This study aimed to compare the variation of cancellous bones at four skeletal sites: lumbar vertebra, femoral neck, mandibular angle and rib in ovariectomized sheep. Sixteen adult sheep were randomly divided into two groups: eight sheep were ovariectomized served as experimental group; the other eight untreated sheep were served as control group. Bone mineral density was assessed by dual-energy X-ray absorptiometry on lumbar vertebrae at baseline and twelve months after ovariectomy. After 12 months, lumbar vertebrae L3 and L4, femoral necks, mandibular angles and the fourth ribs were harvested for micro-CT scanning, histological analysis and biomechanical test. The results showed that bone mineral density of lumbar vertebra decreased significantly in twelfth month (pbone volume/total volume decreased by 45.6%, 36.1% 21.3% and 18.7% in lumbar vertebrae, femoral necks, mandibular angles and ribs in experimental group (pbones to oestrogen deficiency in ovariectomized sheep was site-specific on a pattern as follows: lumbar vertebra, femoral neck, mandibular angle and rib. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of parietal bone surrogates for parietal graft lift training

Directory of Open Access Journals (Sweden)

Hollensteiner Marianne

2016-09-01

Full Text Available Currently the surgical training of parietal bone graft techniques is performed on patients or specimens. Commercially available bone models do not deliver realistic haptic feedback. Thus customized parietal skull surrogates were developed for surgical training purposes. Two human parietal bones were used as reference. Based on the measurement of insertion forces of drilling, milling and saw procedures suitable material compositions for molding cortical and cancellous calvarial layers were found. Artificial skull caps were manufactured and tested. Additionally microtomograpy images of human and artificial parietal bones were performed to analyze outer table and diploe thicknesses. Significant differences between human and artificial skulls were not detected with the mechanical procedures tested. Highly significant differences were found for the diploe thickness values. In conclusion, an artificial bone has been created, mimicking the properties of human parietal bone thus being suitable for tabula externa graft lift training.

Bone grafting: An overview

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D. O. Joshi

2010-08-01

Full Text Available Bone grafting is the process by which bone is transferred from a source (donor to site (recipient. Due to trauma from accidents by speedy vehicles, falling down from height or gunshot injury particularly in human being, acquired or developmental diseases like rickets, congenital defects like abnormal bone development, wearing out because of age and overuse; lead to bone loss and to replace the loss we need the bone grafting. Osteogenesis, osteoinduction, osteoconduction, mechanical supports are the four basic mechanisms of bone graft. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. An ideal bone graft material is biologically inert, source of osteogenic, act as a mechanical support, readily available, easily adaptable in terms of size, shape, length and replaced by the host bone. Except blood, bone is grafted with greater frequency. Bone graft indicated for variety of orthopedic abnormalities, comminuted fractures, delayed unions, non-unions, arthrodesis and osteomyelitis. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. By adopting different procedure of graft preservation its antigenicity can be minimized. The concept of bone banking for obtaining bone grafts and implants is very useful for clinical application. Absolute stability require for successful incorporation. Ideal bone graft must possess osteogenic, osteoinductive and osteocon-ductive properties. Cancellous bone graft is superior to cortical bone graft. Usually autologous cancellous bone graft are used as fresh grafts where as allografts are employed as an alloimplant. None of the available type of bone grafts possesses all these properties therefore, a single type of graft cannot be recomm-ended for all types of orthopedic abnormalities. Bone grafts and implants can be selected as per clinical problems, the equipments available and preference of

The hydroxylapatite-bone interface: 10 years after implant installation.

NARCIS (Netherlands)

Beekmans, H.C.; Meijer, G.J.; Barkhuysen, R.; Blijdorp, P.A.; Merkx, M.A.W.; Jansen, J.A.

2008-01-01

Reconstruction of a severely atrophied maxilla by sinus augmentation with a mixture of hydroxylapatite (HA) granules and autologous cancellous bone is claimed to be a predictable means to facilitate implant placement. To the authors' knowledge, this is the first human histological case report of

Use of dual-energy computed tomography to measure skeletal-wide marrow composition and cancellous bone mineral density.

Science.gov (United States)

Arentsen, Luke; Hansen, Karen E; Yagi, Masashi; Takahashi, Yutaka; Shanley, Ryan; McArthur, Angela; Bolan, Patrick; Magome, Taiki; Yee, Douglas; Froelich, Jerry; Hui, Susanta K

2017-07-01

Temporal and spatial variations in bone marrow adipose tissue (MAT) can be indicative of several pathologies and confound current methods of assessing immediate changes in bone mineral remodeling. We present a novel dual-energy computed tomography (DECT) method to monitor MAT and marrow-corrected volumetric BMD (mcvBMD) throughout the body. Twenty-three cancellous skeletal sites in 20 adult female cadavers aged 40-80 years old were measured using DECT (80 and 140 kVp). vBMD was simultaneous recorded using QCT. MAT was further sampled using MRI. Thirteen lumbar vertebrae were then excised from the MRI-imaged donors and examined by microCT. After MAT correction throughout the skeleton, significant differences (p < 0.05) were found between QCT-derived vBMD and DECT-derived mcvBMD results. McvBMD was highly heterogeneous with a maximum at the posterior skull and minimum in the proximal humerus (574 and 0.7 mg/cc, respectively). BV/TV and BMC have a nearly significant correlation with mcvBMD (r = 0.545, p = 0.057 and r = 0.539, p = 0.061, respectively). MAT assessed by DECT showed a significant correlation with MRI MAT results (r = 0.881, p < 0.0001). Both DECT- and MRI-derived MAT had a significant influence on uncorrected vBMD (r = -0.86 and r = -0.818, p ≤ 0.0001, respectively). Conversely, mcvBMD had no correlation with DECT- or MRI-derived MAT (r = 0.261 and r = 0.067). DECT can be used to assess MAT while simultaneously collecting mcvBMD values at each skeletal site. MAT is heterogeneous throughout the skeleton, highly variable, and should be accounted for in longitudinal mcvBMD studies. McvBMD accurately reflects the calcified tissue in cancellous bone.

Evaluation of demineralized bone and bone transplants in vitro and in vivo with cone beam computed tomography imaging.

Science.gov (United States)

Draenert, F G; Gebhart, F; Berthold, M; Gosau, M; Wagner, W

2010-07-01

The objective of this study was to determine the ability of two flat panel cone beam CT (CBCT) devices to identify demineralized bone and bone transplants in vivo and in vitro. Datasets from patients with autologous bone grafts (n = 9, KaVo 3DeXam (KaVo, Biberach, Germany); n = 38, Accuitomo 40 (Morita, Osaka, Japan)) were retrospectively evaluated. Demineralized and non-demineralized porcine cancellous bone blocks were examined with the two CBCT devices. A SawBone skull (Pacific Research Laboratories, Vashon, WA) was used as a positioning tool for the bone blocks. Descriptive evaluation and image quality assessment were conducted on the KaVo 3DeXam data (voxel size 0.3 mm) using the OsiriX viewer as well as on the Morita Accuitomo data (voxel size 0.25 mm) using proprietary viewer software. Both in vivo and in vitro, the descriptive analysis of the images of the two devices showed well-visualized bone transplants with clearly defined cancellous bones and well-defined single bone trabeculae in all cross-sections. In vitro, demineralized samples showed lower radiographic opacity but no significant loss of quality compared with fresh bone (P = 0.070). Single cancellous bone trabeculae were significantly better visualized with the Morita 3D Accuitomo device than with the KaVo 3DeXam device (P = 0.038). Both the KaVo 3DeXam and Morita 3D Accuitomo devices produce good-quality images of cancellous bones in in vivo remodelling as well as after in vitro demineralization.

The effects of orbital spaceflight on bone histomorphometry and messenger ribonucleic acid levels for bone matrix proteins and skeletal signaling peptides in ovariectomized growing rats

Science.gov (United States)

Cavolina, J. M.; Evans, G. L.; Harris, S. A.; Zhang, M.; Westerlind, K. C.; Turner, R. T.

1997-01-01

A 14-day orbital spaceflight was performed using ovariectomized Fisher 344 rats to determine the combined effects of estrogen deficiency and near weightlessness on tibia radial bone growth and cancellous bone turnover. Twelve ovariectomized rats with established cancellous osteopenia were flown aboard the space shuttle Columbia (STS-62). Thirty ovariectomized rats were housed on earth as ground controls: 12 in animal enclosure modules, 12 in vivarium cages, and 6 killed the day of launch for baseline measurements. An additional 18 ovary-intact rats were housed in vivarium cages as ground controls: 8 rats were killed as baseline controls and the remaining 10 rats were killed 14 days later. Ovariectomy increased periosteal bone formation at the tibia-fibula synostosis; cancellous bone resorption and formation in the secondary spongiosa of the proximal tibial metaphysis; and messenger RNA (mRNA) levels for the prepro-alpha2(1) subunit of type 1 collagen, osteocalcin, transforming growth factor-beta, and insulin-like growth factor I in the contralateral proximal tibial metaphysis and for the collagen subunit in periosteum pooled from tibiae and femora and decreased cancellous bone area. Compared to ovariectomized weight-bearing rats, the flight group experienced decreases in periosteal bone formation, collagen subunit mRNA levels, and cancellous bone area. The flight rats had a small decrease in the cancellous mineral apposition rate, but no change in the calculated bone formation rate. Also, spaceflight had no effect on cancellous osteoblast and osteoclast perimeters or on mRNA levels for bone matrix proteins and signaling peptides. On the other hand, spaceflight resulted in an increase in bone resorption, as ascertained from the diminished retention of a preflight fluorochrome label. This latter finding suggests that osteoclast activity was increased. In a follow-up ground-based experiment, unilateral sciatic neurotomy of ovariectomized rats resulted in cancellous

Vancomycin graft composite for infected bone defects

International Nuclear Information System (INIS)

Winkler, H.; Janata, O.; Georgopoulos, A.

1999-01-01

Reconstructive surgery under septic conditions represents a major challenge in orthopaedics. Local application of antibiotics can provide high drug levels at the site of infection without systemic effects. However, removal of non-resorbable implants and filling of defects usually requires additional operative procedures. An ideal antibiotic carrier should provide for : 1) Effective bactericidal activity, especially against staphylococci including MRSA; 2) High and long lasting levels at the site of infection without local or systemic toxicity; 3) Repair of defects without a second stage procedure. Allogeneic cancellous bone is proven to be effective in restoration of bone stock. Vancomycin is effective against all gram-positive populations and the agent of choice for infections with MRSA. The aim of our study is to investigate the efficacy of a combination of both components in bone infection. Cancellous bone of human origin was processed during several steps and incubated in 10% vancomycin solution. The antimicrobial activity of the vancomycin graft composite (VGC) was evaluated using an agar diffusion bioassay against staphylococcus aureus and high performance liquid chromatography (HPLC). The testing period was up to 9 weeks. Elution of vancomycin from the graft was evaluated in 2.5% human albumin solution, which was exchanged every 24 hours. Concentration of vancomycin in allograft-bone was between 6.653[tg/g and 23.194gg/g with an average of 15.250 [tg/g, which is equivalent to 10.000 times the minimum inhibitory concentration (MIC) for s. aureus. The initial activity decreased to approx. 50% during the first week and approx. 30% at the end of the 9th week. The lowest values measured exceeded the MIC by 2000 times. Concentration in surrounding fluid decreased from 24.395,80 to 18,43pg/ml after 11 complete exchanges. Human cancellous bone, processed in an adequate way, offers capability to store high quantities of vancomycin. Vancomycin graft composites are

Tissue engineering for lateral ridge augmentation with recombinant human bone morphogenetic protein 2 combination therapy: a case report.

Science.gov (United States)

Mandelaris, George A; Spagnoli, Daniel B; Rosenfeld, Alan L; McKee, James; Lu, Mei

2015-01-01

This case report describes a tissue-engineered reconstruction with recombinant human bone morphogenetic protein 2/acellular collagen sponge (rhBMP-2/ ACS) + cancellous allograft and space maintenance via Medpor Contain mesh in the treatment of a patient requiring maxillary and mandibular horizontal ridge augmentation to enable implant placement. The patient underwent a previously unsuccessful corticocancellous bone graft at these sites. Multiple and contiguous sites in the maxilla and in the mandibular anterior, demonstrating advanced lateral ridge deficiencies, were managed using a tissue engineering approach as an alternative to autogenous bone harvesting. Four maxillary and three mandibular implants were placed 9 and 10 months, respectively, after tissue engineering reconstruction, and all were functioning successfully after 24 months of follow-up. Histomorphometric analysis of a bone core obtained at the time of the maxillary implant placement demonstrated a mean of 76.1% new vital bone formation, 22.2% marrow/cells, and 1.7% residual graft tissue. Tissue engineering for lateral ridge augmentation with combination therapy requires further research to determine predictability and limitations.

Multiple-energy tissue-cancellation applications of a digital beam attenuator to chest radiography

International Nuclear Information System (INIS)

Dobbins, J.T. III.

1985-01-01

The digitally-formed primary beam attenuator (DBA) spatially modulates the x-ray fluence incident upon the patient to selectively attenuate regions of interest. The DBA attenuating mask is constructed from CeO 2 powder by a modified printing technique and uses image information from an initial low-dose exposure. Two tissue-cancellation imaging techniques are investigated with the DBA: (1) energy-dependent information is used to form a beam attenuator that attenuates specific tissues in the primary x-ray beam for tissue-cancelled film radiography; (2) the beam attenuator is used to improve image signal-to-noise and scattered radiation properties in traditional energy-subtraction tissue-cancellation imaging with digital detectors. The tissue-cancellation techniques in the primary x-ray beam were capable of adequately removing either soft-tissue or bone from the final compensated film radiograph when using a phantom with well defined soft-tissue and bone sections. However, when tried on an anthropomorphic chest phantom the results were adequate for cancellation of large soft tissue structures, but unsatisfactory for cancellation of bony structures such as the ribs, because of the limited spatial frequency content of the attenuating mask. The second technique (with digital detectors) showed improved uniformity of image signal-to-noise and a two-fold increase in soft-tissue nodule contrast due to improved scattered radiation properties. The tissue-cancelled images contained residual image contributions from the presence of the attenuating mask, but this residual may be correctable by future algorithms

The influence of lifelong exposure to environmental fluoride on bone quality in humans

Science.gov (United States)

Chachra, Debbie

The objective of this study was to determine if lifelong exposure to environmental sources of fluoride (including fluoridated water) had an effect on bone quality in humans. Ninety-two femoral heads were obtained from individuals undergoing total hip arthroplasty in regions with and without fluoridated water (Toronto and Montreal, respectively), so that the donors would have had a wide range of fluoride exposure. As the samples were obtained at surgery, the femoral heads were affected by osteoarthritis (75), osteoporosis (9) and other diseases. The fluoride content of cancellous bone was assessed by instrumental neutron activation analysis. A number of contributors to bone quality were assessed. The compressive and torsional mechanical properties were measured for cancellous cores excised from the centre of the femoral head. The architecture was assessed by image analysis of an x-ray of a 5 mm thick coronal section of the femoral head, as well as of histological sections taken from the superior (weightbearing) and the inferior (nonweightbearing) surface of the femoral head. The degree of mineralization was measured using backscattered electron imaging and microhardness, again at the superior and the inferior surface. Femoral heads from Toronto donors had a greater mean fluoride content than those from Montreal donors (1033 +/- 438 ppm vs. 643 +/- 220 ppm). However, the fluoride content of the Toronto donors ranged approximately twelve-fold (192--2264 ppm) and entirely contained the range of Montreal donors. Therefore, fluoridated water exposure is not the only determinant of fluoride content. The logarithm of the bone fluoride content increased with age. No substantive effect of fluoride, independent of age, was observed for the mechanical properties. Similarly, at the inferior surface, the architecture was affected by age but not by fluoride incorporation but the degree of mineralization was not affected by either. However, the degree of mineralization (measured

Bone density does not reflect mechanical properties in early-stage arthrosis

DEFF Research Database (Denmark)

Ding, Ming; Danielsen, CC; Hvid, I

2001-01-01

: medial arthrosis, lateral control, normal medial and normal lateral controls. The specimens were tested in compression to determine mechanical properties and then physical/compositional properties. Compared to the normal medial control, we found reductions in ultimate stress, Young's modulus, and failure...... cancellous bone and the 3 controls. None of the mechanical properties of arthrotic cancellous bone could be predicted by the physical/compositional properties measured. The increase in bone tissue in early-stage arthrotic cancellous bone did not make up for the loss of mechanical properties, which suggests...

Comparative cortical bone thickness between the long bones of humans and five common non-human mammal taxa.

Science.gov (United States)

Croker, Sarah L; Reed, Warren; Donlon, Denise

2016-03-01

The task of identifying fragments of long bone shafts as human or non-human is difficult but necessary, for both forensic and archaeological cases, and a fast simple method is particularly useful. Previous literature suggests there may be differences in the thickness of the cortical bone between these two groups, but this has not been tested thoroughly. The aim of this study was not only to test this suggestion, but also to provide data that could be of practical assistance for future comparisons. The major limb bones (humerus, radius, femur and tibia) of 50 Caucasoid adult skeletons of known age and sex were radiographed, along with corresponding skeletal elements from sheep, pigs, cattle, large dogs and kangaroos. Measurements were taken from the radiographs at five points along the bone shaft, of shaft diameter, cortical bone thickness, and a cortical thickness index (sum of cortices divided by shaft diameter) in both anteroposterior and mediolateral orientations. Each variable for actual cortical bone thickness as well as cortical thickness indices were compared between the human group (split by sex) and each of the non-human groups in turn, using Student's t-tests. Results showed that while significant differences did exist between the human groups and many of the non-human groups, these were not all in the same direction. That is, some variables in the human groups were significantly greater than, and others were significantly less than, the corresponding variable in the non-human groups, depending on the particular non-human group, sex of the human group, or variable under comparison. This was the case for measurements of both actual cortical bone thickness and cortical thickness index. Therefore, for bone shaft fragments for which the skeletal element is unknown, the overlap in cortical bone thickness between different areas of different bones is too great to allow identification using this method alone. However, by providing extensive cortical bone

High-strength mineralized collagen artificial bone

Science.gov (United States)

Qiu, Zhi-Ye; Tao, Chun-Sheng; Cui, Helen; Wang, Chang-Ming; Cui, Fu-Zhai

2014-03-01

Mineralized collagen (MC) is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal's cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in vivo implantation assay demonstrated good biocompatibility of the material, and in vivo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load-bearing sites.

Perfluoroalkyl substances in human bone: concentrations in bones and effects on bone cell differentiation.

Science.gov (United States)

Koskela, A; Koponen, J; Lehenkari, P; Viluksela, M; Korkalainen, M; Tuukkanen, J

2017-07-28

Perfluoroalkyl substances (PFAS), including two most commonly studied compounds perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are widely distributed environmental pollutants, used extensively earlier. Due to their toxicological effects the use of PFAS is now regulated. Based on earlier studies on PFOA's distribution in bone and bone marrow in mice, we investigated PFAS levels and their possible link to bone microarchitecture of human femoral bone samples (n = 18). Soft tissue and bone biopsies were also taken from a 49-year old female cadaver for PFAS analyses. We also studied how PFOA exposure affects differentiation of human osteoblasts and osteoclasts. PFAS were detectable from all dry bone and bone marrow samples, PFOS and PFOA being the most prominent. In cadaver biopsies, lungs and liver contained the highest concentrations of PFAS, whereas PFAS were absent in bone marrow. Perfluorononanoic acid (PFNA) was present in the bones, PFOA and PFOS were absent. In vitro results showed no disturbance in osteogenic differentiation after PFOA exposure, but in osteoclasts, lower concentrations led to increased resorption, which eventually dropped to zero after increase in PFOA concentration. In conclusion, PFAS are present in bone and have the potential to affect human bone cells partly at environmentally relevant concentrations.

Three-dimensional quantitative CT of the proximal femur: Relationship to vertebral trabecular bone density

International Nuclear Information System (INIS)

Bhasin, S.; Zlatkin, M.B.; Sartoris, D.J.; Andre, M.; Resnick, D.

1987-01-01

Integrated cancellous, cortical, and total bone density in the femoral neck and inter-trochanteric region was measured bilaterally in 25 women aged 35-90 years (mean age, 65). Contiguous-section (1-cm-thick) data were analyzed using three-dimensional histogram software on a Cemax 1000 image processor. Single-section quantitative CT was used to determine mean mineral equivalent values for vertebral cancellous bone from T-11 to L-3 in each woman. Significant correlation was found between cancellous bone density at the two sites. Cortical and total bone densities in the proximal femur were predicted less well with vertebral cancellous data, suggesting a greater dependence on weight-bearing and activity factors

The Use of Recombinant Human Platelet-Derived Growth Factor for Maxillary Sinus Augmentation.

Science.gov (United States)

Kubota, Atsushi; Sarmiento, Hector; Alqahtani, Mohammed Saad; Llobell, Arturo; Fiorellini, Joseph P

The maxillary sinus augmentation procedure has become a predictable treatment to regenerate bone for implant placement. The purpose of this study was to evaluate the effect of recombinant human platelet-derived growth factor BB (rhPDGF-BB) combined with a deproteinized cancellous bovine bone graft for sinus augmentation. The lateral window approach was used for maxillary sinuses with minimal residual bone. After a healing period of 4 months, dental implants were placed and then restored following a 2-month osseointegration period. The result demonstrated increased bone height and ISQ values and a 100% survival rate. This study indicates that the addition of rhPDGF-BB to deproteinized cancellous bovine bone accelerated the healing period in maxillary sinuses with minimal native bone.

Late Effects of Heavy Ion Irradiation on Ex Vivo Osteoblastogenesis and Cancellous Bone Microarchitecture

Science.gov (United States)

Tran, Luan Hoang; Alwood, Joshua; Kumar, Akhilesh; Limoli, C. L.; Globus, Ruth

2012-01-01

. Thus, both low and high doses of heavy ion irradiation cause time dependent, adaptive changes in redox state within marrow cells but only high doses (50, 200cGy) inhibit osteoblastogenesis and cause cancellous bone loss. We conclude space radiation has the potential to cause persistent damage to bone marrow derived stem and progenitor cells for osteoblasts despite adaptive changes in cellular redox state.

Does collagen trigger the recruitment of osteoblasts into vacated bone resorption lacunae during bone remodeling?

DEFF Research Database (Denmark)

Abdelgawad, Mohamed Essameldin; Søe, Kent; Andersen, Thomas Levin

2014-01-01

matrix molecules, collagen's potency was superior and only equaled by fibronectin. Next, the majority of the newly recruited osteoblast lineage cells positioned immediately next to the osteoclasts exhibit uPARAP/Endo180, an endocytic collagen receptor reported to be involved in collagen internalization......Osteoblast recruitment during bone remodeling is obligatory to re-construct the bone resorbed by the osteoclast. This recruitment is believed to be triggered by osteoclast products and is therefore likely to start early during the remodeling cycle. Several osteoclast products with osteoblast...... recruitment potential are already known. Here we draw the attention on the osteoblast recruitment potential of the collagen that is freshly demineralized by the osteoclast. Our evidence is based on observations on adult human cancellous bone, combined with in vitro assays. First, freshly eroded surfaces where...

A reversal phase arrest uncoupling the bone formation and resorption contributes to the bone loss in glucocorticoid treated ovariectomised aged sheep

DEFF Research Database (Denmark)

Andreasen, Christina Møller; Ding, Ming; Overgaard, Søren

2015-01-01

Large animals as sheep are often used as models for human osteoporosis. Our aim was therefore to determine how glucocorticoid treatment of ovariectomised sheep affects the cancellous bone, determining the cellular events within the bone remodelling process that contributes to their bone loss...... in postmenopausal women with glucocorticoid-induced osteoporosis. This supports the relevance of the sheep model to the pathophysiology of glucocorticoid-induced osteoporosis in postmenopausal women, making it a relevant preclinical model for orthopaedic implant and biomaterial research........ Twenty female sheep were assigned for two groups; an untreated control group and an ovariectomised group treated with glucocorticoids (0.6mg/kg/day, 5 times weekly) for 7months. At 7months the glucocorticoid-treated ovariectomised sheep showed a significant change in the bone microstructure revealed...

Bone growth and turnover in progesterone receptor knockout mice.

Energy Technology Data Exchange (ETDEWEB)

Rickard, David J.; Iwaniec, Urszula T.; Evans, Glenda; Hefferan, Theresa E.; Hunter, Jaime C.; Waters, Katrina M.; Lydon, John P.; O' Malley, Bert W.; Khosla, Sundeep; Spelsberg, Thomas C.; Turner, Russell T.

2008-05-01

The role of progesterone receptor (PR) signaling in skeletal metabolism is controversial. To address whether signaling through the PR is necessary for normal bone growth and turnover, we performed histomorphometric and mCT analyses of bone from homozygous female PR knockout (PRKO) mice at 6, 12, and 26 weeks of age. These mice possess a null mutation of the PR locus, which blocks the gene expression of A and B isoforms of PR. Body weight gain, uterine weight gain and tibia longitudinal bone growth was normal in PRKO mice. In contrast, total and cortical bone mass were increased in long bones of post-pubertal (12 and 26-week-old) PRKO mice, whereas cancellous bone mass was normal in the tibia but increased in the humerus. The striking 57% decrease in cancellous bone from the proximal tibia metaphysis which occurred between 6 and 26 weeks in WT mice was abolished in PRKO mice. The improved bone balance in aging PRKO mice was associated with elevated bone formation and a tendency toward reduced osteoclast perimeter. Taken together, these findings suggest that PR signaling in mice attenuates the accumulation of cortical bone mass during adolescence and is required for early age-related loss of cancellous bone.

Metabolic Syndrome and Bone: Pharmacologically Induced Diabetes has Deleterious Effect on Bone in Growing Obese Rats.

Science.gov (United States)

Bagi, Cedo M; Edwards, Kristin; Berryman, Edwin

2017-12-01

Metabolic syndrome and osteoporosis share similar risk factors. Also, patients with diabetes have a higher risk of osteoporosis and fracture. Liver manifestations, such as non-alcoholic steatohepatitis (NASH), of metabolic syndrome are further aggravated in diabetics and often lead to liver failure. Our objective was to create a rat model of human metabolic syndrome and determine the long-term impact of early-onset T1D on bone structure and strength in obese growing rats. Male rats were given either standard chow and RO water (Controls) or a high-fat, high-cholesterol diet and sugar water containing 55% fructose and 45% glucose (HFD). A third group of rats received the HFD diet and a single dose of streptozotocin to induce type 1 diabetes (HFD/Sz). Body weight and glucose tolerance tests were conducted several times during the course of the study. Serum chemistry, liver enzymes, and biomarkers of bone metabolism were evaluated at 10 and 28 weeks. Shear wave elastography and histology were used to assess liver fibrosis. Cancellous bone structure and cortical bone geometry were evaluated by mCT and strength by the 3-point bending method. Body mass and fat accumulation was significantly higher in HFD and HFD/Sz rats compared to Controls. Rats in both the HFD and HFD/Sz groups developed NASH, although the change was more severe in diabetic rats. Although both groups of obese rats had larger bones, their cancellous structure and cortical thickness were reduced, resulting in diminished strength that was further aggravated by diabetes. The HFD and HFD/Sz rats recapitulate MeSy in humans with liver pathology consistent with NASH. Our data provide strong indication that obesity accompanied by type 1 diabetes significantly aggravates comorbidities of MeSy, including the development of osteopenia and weaker bones. The juvenile rat skeleton seems to be more vulnerable to damage imposed by obesity and diabetes and may offer a model to inform the underlying pathology associated

In vitro assessment of biomaterial-induced remodeling of subchondral and cancellous bone for the early intervention of joint degeneration with focus on the spinal disc

Science.gov (United States)

McCanless, Jonathan D.

Osteoarthritis-associated pain of the spinal disc, knee, and hip derives from degeneration of cartilagenous tissues in these joints. Traditional therapies have focused on these cartilage (and disc specific nucleus pulposus) changes as a means of treatment through tissue grafting, regenerative synthetic implants, non-regenerative space filling implants, arthroplasty, and arthrodesis. Although such approaches may seem apparent upon initial consideration of joint degeneration, tissue pathology has shown changes in the underlying bone and vascular bed precede the onset of cartilaginous changes. It is hypothesized that these changes precedent joint degeneration and as such may provide a route for early prevention. The current work proposes an injectable biomaterial-based therapy within these subchondral and cancellous bone regions as a means of preventing or reversing osteoarthritis. Two human concentrated platelet releasate-containing alginate hydrogel/beta-tricalcium phosphate composites have been developed for this potential biomaterial application. The undertaking of assessing these materials through bench-, in vitro, and ex vivo work is described herein. These studies showed the capability of the biomaterials to initiate a wound healing response in monocytes, angiogenic and differentiation behavior in immature endothelial cells, and early osteochondral differentiation in mesenchymal stem cells. These cellular activities are associated with fracture healing and endochondral bone formation, demonstrating the potential of the biomaterials to induce osseous and vascular tissue remodeling underlying osteoarthritic joints as a novel therapy for a disease with rapidly growing healthcare costs.

Characterization of Bone Marrow Mononuclear Cells on Biomaterials for Bone Tissue Engineering In Vitro

Science.gov (United States)

Verboket, René; Kontradowitz, Kerstin; Oppermann, Elsie; Brune, Jan C.; Nau, Christoph; Meier, Simon; Bonig, Halvard; Marzi, Ingo; Seebach, Caroline

2015-01-01

Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma), demineralized bone matrix (DBM), and bovine cancellous bone (BS) were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo. PMID:25802865

Characterization of bone marrow mononuclear cells on biomaterials for bone tissue engineering in vitro.

Science.gov (United States)

Henrich, Dirk; Verboket, René; Schaible, Alexander; Kontradowitz, Kerstin; Oppermann, Elsie; Brune, Jan C; Nau, Christoph; Meier, Simon; Bonig, Halvard; Marzi, Ingo; Seebach, Caroline

2015-01-01

Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma), demineralized bone matrix (DBM), and bovine cancellous bone (BS) were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo.

Characterization of Bone Marrow Mononuclear Cells on Biomaterials for Bone Tissue Engineering In Vitro

Directory of Open Access Journals (Sweden)

Dirk Henrich

2015-01-01

Full Text Available Bone marrow mononuclear cells (BMCs are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma, demineralized bone matrix (DBM, and bovine cancellous bone (BS were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo.

Atomic scale chemical tomography of human bone

Science.gov (United States)

Langelier, Brian; Wang, Xiaoyue; Grandfield, Kathryn

2017-01-01

Human bone is a complex hierarchical material. Understanding bone structure and its corresponding composition at the nanometer scale is critical for elucidating mechanisms of biomineralization under healthy and pathological states. However, the three-dimensional structure and chemical nature of bone remains largely unexplored at the nanometer scale due to the challenges associated with characterizing both the structural and chemical integrity of bone simultaneously. Here, we use correlative transmission electron microscopy and atom probe tomography for the first time, to our knowledge, to reveal structures in human bone at the atomic level. This approach provides an overlaying chemical map of the organic and inorganic constituents of bone on its structure. This first use of atom probe tomography on human bone reveals local gradients, trace element detection of Mg, and the co-localization of Na with the inorganic-organic interface of bone mineral and collagen fibrils, suggesting the important role of Na-rich organics in the structural connection between mineral and collagen. Our findings provide the first insights into the hierarchical organization and chemical heterogeneity in human bone in three-dimensions at its smallest length scale - the atomic level. We demonstrate that atom probe tomography shows potential for new insights in biomineralization research on bone.

Sequential treatment with basic fibroblast growth factor and parathyroid hormone restores lost cancellous bone mass and strength in the proximal tibia of aged ovariectomized rats

DEFF Research Database (Denmark)

Wronski, T.J.; Ratkus, A.M.; Thomsen, Jesper Skovhus

2001-01-01

This study was designed to determine whether sequential treatment with basic fibroblast growth factor (bFGF) and parathyroid hormone (PTH) can restore lost cancellous bone mass and strength at a severely osteopenic skeletal site in aged ovariectomized (OVX) rats. Female Sprague-Dawley rats were...... intravenously (iv) daily with bFGF for 14 days at a dose of 200 microg/kg body weight. At the end of bFGF treatment, one group was killed whereas the other group was subjected to 8 weeks of treatment with synthetic human PTH 1-34 [hPTH(1-34)] consisting of subcutaneous (sc) injections 5 days/week at a dose...... of 80 microg/kg. Another group of OVX rats was treated iv with vehicle for 2 weeks followed by treatment with PTH alone for 8 weeks. Other groups of sham-operated control rats and OVX rats were treated iv and sc with vehicle alone. The right proximal tibia from each rat was processed undecalcified...

Pathogenesis of age-related bone loss in humans.

Science.gov (United States)

Khosla, Sundeep

2013-10-01

Although data from rodent systems are extremely useful in providing insights into possible mechanisms of age-related bone loss, concepts evolving from animal models need to ultimately be tested in humans. This review provides an update on mechanisms of age-related bone loss in humans based on the author's knowledge of the field and focused literature reviews. Novel imaging, experimental models, biomarkers, and analytic techniques applied directly to human studies are providing new insights into the patterns of bone mass acquisition and loss as well as the role of sex steroids, in particular estrogen, on bone metabolism and bone loss with aging in women and men. These studies have identified the onset of trabecular bone loss at multiple sites that begins in young adulthood and remains unexplained, at least based on current paradigms of the mechanisms of bone loss. In addition, estrogen appears to be a major regulator of bone metabolism not only in women but also in men. Studies assessing mechanisms of estrogen action on bone in humans have identified effects of estrogen on RANKL expression by several different cell types in the bone microenvironment, a role for TNF-α and IL-1β in mediating effects of estrogen deficiency on bone, and possible regulation of the Wnt inhibitor, sclerostin, by estrogen. There have been considerable advances in our understanding of age-related bone loss in humans. However, there are also significant gaps in knowledge, particularly in defining cell autonomous changes in bone in human studies to test or validate concepts emerging from studies in rodents. Decision Editor: Luigi Ferrucci, MD, PhD.

Changes in bone geometry and microarchitecture caused by intermittent administration of PTH. Comparison with those by exercise load

International Nuclear Information System (INIS)

Mori, Keiya

2010-01-01

There have been several studies showing that periodical intermittent medication with parathyroid hormone (PTH) causes increases in cancellous bone mass. However, there have been almost no reports comparing the effects of periodical intermittent PTH medication on bone microarchitecture with changes caused by physiological stimulation such as exercise load. In this study, we compared the effects of these two interventions on the microarchitecturural deterioration of femoral cancellous bone associated with unloading, using micro-computed tomography (micro-CT), and the effects of PTH administration and motion loading on improvement of the deteriorated structure. In the study, 32 eight-week-old male Wistar rats were divided into four groups: a control group without tail suspension (CON), a control recovery group after suspension (S+C), a suspension/PTH group (S+P), and a suspension/jumping exercise group (S+J). Periodical intermittent human PTH (1-34) was given periodically to the S+P group rats at a dose of 75 μg/kg/day five times a week for five weeks, after two weeks of exercise with suspension of the tail. The rats in the S+J group performed 40 cm-high jumping 10 times/day five times a week for five weeks. After this conditioning, upon examination, bilateral femurs were removed and the right distal metaphysis was scanned using micro-CT to obtain images of the cancellous bone region of the femur. Based on the tomographic data, indices of cancellous bone microarchitecture was the index of trabecular bone structure were determined by using three-dimensional image analysis system. In addition, to examine the geometric properties of the diaphysis, mid-portion images of the bone shaft of the left femur were obtained by micro-CT, and then the mechanical bone strength of the left femur was determined by performing a three-point bending test. Compared to the S+C group, the S+P and S+J groups showed significantly higher bone volume, bone surface mass values, superficial bone

Alien Noise Cancellation

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Full FEXT Cancellation. Expectation Maximization based Algorithms. Partial Cancellation. Optimal Choice of what to Cancel and what not to! Alien Noise Cancellation. Efficient Crosstalk channel estimation. In addition:

Porous bioresorbable magnesium as bone substitute

Energy Technology Data Exchange (ETDEWEB)

Wen, C.E.; Yamada, Y.; Shimojima, K.; Chino, Y.; Hosokawa, H.; Mabuchi, M. [Inst. for Structural and Engineering Materials, National Inst. of Advanced Industrial Science and Technology, Nagoya (Japan)

2003-07-01

Recently magnesium has been recognized as a very promising biomaterial for bone substitutes because of its excellent properties of biocompatibility, biodegradability and bioresorbability. In the present study, magnesium foams were fabricated by using a powder metallurgical process. Scanning electron microscopy equipped with energy dispersive X-ray spectrometer (EDS) and compressive tester were used to characterize the porous magnesium. Results show that the Young's modulus and the peak stress of the porous magnesium increase with decreasing porosity and pore size. This study suggests that the mechanical properties of the porous magnesium with the low porosity of 35% and/or with the small pore size of about 70 {mu}m are close to those of human cancellous bones. (orig.)

[On the preparation and mechanical properties of PVA hydrogel bionic cartilage/bone composite artificial articular implants].

Science.gov (United States)

Meng, Haoye; Zheng, Yudong; Huang, Xiaoshan; Yue, Bingqing; Xu, Hong; Wang, Yingjun; Chen, Xiaofeng

2010-10-01

In view of the problems that conventional artificial cartilages have no bioactivity and are prone to peel off in repeated uses as a result of insufficient strength to bond with subchondral bone, we have designed and prepared a novel kind of PVA-BG composite hydrogel as bionic artificial articular cartilage/bone composite implants. The effects of processes and conditions of preparation on the mechanical properties of implant were explored. In addition, the relationships between compression strain rate, BG content, PVA hydrogels thickness and compressive tangent modulus were also explicated. We also analyzed the effects of cancellous bone aperture, BG and PVA content on the shear strength of bonding interface of artificial articular cartilage with cancellous bone. Meanwhile, the bonding interface of artificial articular cartilage and cancellous bone was characterized by scanning electron microscopy. It was revealed that the compressive modulus of composite implants was correspondingly increased with the adding of BG content and the augments of PVA hydrogel thickness. The compressive modulus and bonding interface were both related to the apertures of cancellous bone. The compressive modulus of composite implants was 1.6-2.23 MPa and the shear strength of bonding interface was 0.63-1.21 MPa. These results demonstrated that the connection between artificial articular cartilage and cancellous bone was adequately firm.

Plasma-sprayed titanium coating to polyetheretherketone improves the bone-implant interface.

Science.gov (United States)

Walsh, William R; Bertollo, Nicky; Christou, Chrisopher; Schaffner, Dominik; Mobbs, Ralph J

2015-05-01

Rapid and stable fixation at the bone-implant interface would be regarded as one of the primary goals to achieve clinical efficacy, regardless of the surgical site. Although mechanical and physical properties of polyetheretherketone (PEEK) provide advantages for implant devices, the hydrophobic nature and the lack of direct bone contact remains a limitation. To examine the effects of a plasma-sprayed titanium coated PEEK on the mechanical and histologic properties at the bone-implant interface. A preclinical laboratory study. Polyetheretherketone and plasma-sprayed titanium coated PEEK implants (Ti-bond; Spinal Elements, Carlsbad, CA, USA) were placed in a line-to-line manner in cortical bone and in a press-fit manner in cancellous bone of adult sheep using an established ovine model. Shear strength was assessed in the cortical sites at 4 and 12 weeks, whereas histology was performed in cortical and cancellous sites at both time points. The titanium coating dramatically improved the shear strength at the bone-implant interface at 4 weeks and continued to improve with time compared with PEEK. Direct bone ongrowth in cancellous and cortical sites can be achieved using a plasma-sprayed titanium coating on PEEK. Direct bone to implant bonding can be achieved on PEEK in spite of its hydrophobic nature using a plasma-sprayed titanium coating. The plasma-sprayed titanium coating improved mechanical properties in the cortical sites and the histology in cortical and cancellous sites. Copyright © 2015 Elsevier Inc. All rights reserved.

42 CFR 57.313a - Loan cancellation reimbursement.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Loan cancellation reimbursement. 57.313a Section 57.313a Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR... Loans § 57.313a Loan cancellation reimbursement. In the event that insufficient funds are available to...

Mandibular reconstruction using bone allografts

International Nuclear Information System (INIS)

Chang Joon Yim

1999-01-01

. Combinations of allografts and autografts for mandibular reconstruction have enjoyed great success since their introduction in the late 1960's and early 1970's. Due to its high osteogenic potential, marrow and cancellous bone was used for reconstruction of the mandible. For reconstruction of large defects, surgeons used a scaffold to support the cancellous bone. This practice led to the use of allogeneic bone crib in which the cancellous bone could be packed. Reconstruction of the mandible by this combination is now very commonplace

Increased presence of capillaries next to remodeling sites in adult human cancellous bone

DEFF Research Database (Denmark)

Kristensen, Helene Bjoerg; Andersen, Thomas Levin; Marcussen, Niels

2013-01-01

and at the level of the light-microscopically assessed contact of these three entities with the bone or canopy surfaces. Between 51 and 100 microm, their densities leveled to that found above quiescent surfaces. Electron microscopy asserted the close proximity between BRC canopies and capillaries lined...

Microarchitectural adaptations in aging and osteoarthrotic subchondral bone tissues

DEFF Research Database (Denmark)

Ding, Ming

2010-01-01

. These diseases are among the major health care problems in terms of socio-economic costs. The overall goals of the current series of studies were to investigate the age-related and osteoarthrosis (OA) related changes in the 3-D microarchitectural properties, mechanical properties, collagen and mineral quality......-related development of guinea pig OA; secondly, the potential effects of hyaluronan on OA subchondral bone tissues; and thirdly, the effects on OA progression of an increase in subchondral bone density by inhibition of bone remodeling with a bisphosphonate. These investigations aimed to obtain more insight...... into the age-related and OA-related subchondral bone adaptations.   Microarchitectural adaptation in human aging cancellous bone The precision of micro-CT measurement is excellent. Accurate 3-D micro-CT image datasets can be generated by applying an appropriate segmentation threshold. A fixed threshold may...

Partial Cancellation

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Partial Cancellation. Full Cancellation is desirable. But complexity requirements are enormous. 4000 tones, 100 Users billions of flops !!! Main Idea: Challenge: To determine which cross-talker to cancel on what “tone” for a given victim. Constraint: Total complexity is ...

Effects of long-term alendronate treatment on bone mineralisation, resorption parameters and biomechanics of single human vertebral trabeculae

Directory of Open Access Journals (Sweden)

M Krause

2014-09-01

Full Text Available Due to their well-established fracture risk reduction, bisphosphonates are the most frequently used therapeutic agent to treat osteoporosis. Bisphosphonates reduce fracture risk by suppressing bone resorption, but the lower bone turnover could have a negative impact on bone quality at the tissue level. Here, we directly assess the structural and mechanical characteristics of cancellous bone from the lumbar vertebrae (L5 in non-treated osteoporotic controls (n = 21, mid-term alendronate-treated osteoporotic patients (n = 6, and long-term alendronate-treated osteoporotic patients (n = 7. The strength and toughness of single trabeculae were evaluated, while the structure was characterised through measurements of microdamage accumulation, mineralisation distribution, and histological indices. The alendronate-treated cases had a reduced eroded surface (ES/BS, p < 0.001 and a higher bone mineralisation in comparison to non-treated controls (p = 0.037, which is indicative of low turnover associated with treatment. However, the amount of microdamage and the mechanical properties were similar among the control and treatment groups. As the tissue mineral density (TMD increased significantly with alendronate treatment compared to non-treated osteoporotic controls, the reduction in resorption cavities could counterbalance the higher TMD allowing the alendronate-treated bone to maintain its mechanical properties and resist microdamage accumulation. A multivariate analysis of the possible predictors supports the theory that multiple factors (e.g., body mass index, TMD, and ES/BS can impact the mechanical properties. Our results suggest that long-term alendronate treatment shows no adverse impact on mechanical cancellous bone characteristics.

Compacted cancellous bone has a spring-back effect

DEFF Research Database (Denmark)

Kold, S; Bechtold, JE; Ding, Ming

2003-01-01

A new surgical technique, compaction, has been shown to improve implant fixation. It has been speculated that the enhanced implant fixation with compaction could be due to a spring-back effect of compacted bone. However, such an effect has yet to be shown. Therefore we investigated in a canine mo....... Thus we found a spring-back effect of compacted bone, which may be important for increasing implant fixation by reducing initial gaps between the implant and bone....

Effect of vitamin K2 and growth hormone on the long bones in hypophysectomized young rats: a bone histomorphometry study.

Science.gov (United States)

Iwamoto, Jun; Takeda, Tsuyoshi; Sato, Yoshihiro; Yeh, James K

2007-01-01

The purpose of the present study was to determine whether vitamin K(2) and growth hormone (GH) had an additive effect on the long bones in hypophysectomized young rats. Forty-eight female Sprague-Dawley rats (6 weeks old) were assigned to the following five groups by the stratified weight randomization method: intact controls, hypophysectomy (HX) alone, HX + vitamin K(2) (30 mg/kg, p.o., daily), HX + GH (0.625 mg/kg, s.c., 5 days a week), and HX + vitamin K(2) + GH. The duration of the experiment was 4 weeks. HX resulted in a reduction of the cancellous bone volume/total tissue volume (BV/TV) at the proximal tibial metaphysis, as well as decreasing the total tissue area and cortical area of the tibial diaphysis. These changes resulted from a decrease of the longitudinal growth rate and the bone formation rate (BFR)/TV of cancellous bone, as well as a decrease of the periosteal BFR/bone surface (BS) and an increase of endocortical bone turnover (indicated by the BFR/BS) in cortical bone. Administration of vitamin K(2) to HX rats did not affect the cancellous BV/TV or the cortical area. On the other hand, GH completely prevented the decrease of total tissue area and cortical area in cortical bone, as well as the decrease of marrow area and endocortical circumference, by increasing the periosteal BFR/BS compared with that in intact controls and reversing the increase of endocortical bone turnover (BFR/BS). However, GH only partly improved the reduction of the cancellous BV/TV, despite an increase of the longitudinal growth rate and BFR/TV compared with those of intact controls. When administered with GH, vitamin K(2) counteracted the reduction of endocortical bone turnover (BFR/BS) and circumference caused by GH treatment, resulting in no significant difference of marrow area from that in untreated HX rats. These results suggest that, despite the lack of an obvious effect on bone parameters, vitamin K(2) normalizes the size of the marrow cavity during development of

Multilayer porous UHMWPE scaffolds for bone defects replacement

International Nuclear Information System (INIS)

Maksimkin, A.V.; Senatov, F.S.; Anisimova, N.Yu.; Kiselevskiy, M.V.; Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A.; Kaloshkin, S.D.

2017-01-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.

Multilayer porous UHMWPE scaffolds for bone defects replacement

Energy Technology Data Exchange (ETDEWEB)

Maksimkin, A.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Senatov, F.S., E-mail: senatov@misis.ru [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Anisimova, N.Yu.; Kiselevskiy, M.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); N.N. Blokhin Russian Cancer Research Center, Moscow (Russian Federation); Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A. [State Plant of Medicinal Drugs, Moscow (Russian Federation); Kaloshkin, S.D. [National University of Science and Technology “MISIS”, Moscow (Russian Federation)

2017-04-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.

An in vitro 3D bone metastasis model by using a human bone tissue culture and human sex-related cancer cells.

Science.gov (United States)

Salamanna, Francesca; Borsari, Veronica; Brogini, Silvia; Giavaresi, Gianluca; Parrilli, Annapaola; Cepollaro, Simona; Cadossi, Matteo; Martini, Lucia; Mazzotti, Antonio; Fini, Milena

2016-11-22

One of the main limitations, when studying cancer-bone metastasis, is the complex nature of the native bone environment and the lack of reliable, simple, inexpensive models that closely mimic the biological processes occurring in patients and allowing the correct translation of results. To enhance the understanding of the mechanisms underlying human bone metastases and in order to find new therapies, we developed an in vitro three-dimensional (3D) cancer-bone metastasis model by culturing human breast or prostate cancer cells with human bone tissue isolated from female and male patients, respectively. Bone tissue discarded from total hip replacement surgery was cultured in a rolling apparatus system in a normoxic or hypoxic environment. Gene expression profile, protein levels, histological, immunohistochemical and four-dimensional (4D) micro-CT analyses showed a noticeable specificity of breast and prostate cancer cells for bone colonization and ingrowth, thus highlighting the species-specific and sex-specific osteotropism and the need to widen the current knowledge on cancer-bone metastasis spread in human bone tissues. The results of this study support the application of this model in preclinical studies on bone metastases and also follow the 3R principles, the guiding principles, aimed at replacing/reducing/refining (3R) animal use and their suffering for scientific purposes.

Comparison of radiological changes in humans and beagles with skeletal deposits of radium

Energy Technology Data Exchange (ETDEWEB)

Morgan, J P [Univ. of California, Davis; Pool, R R; Kirsh, I E

1983-01-01

At the Laboratory for Energy-related Health Research at the University of California, Davis, semimonthly injections of /sup 226/Ra were given to a group of beagle dogs, and periodic skeletal radiography followed, as well as histological studies of the bones. At the Center for Human Radiobiology measurements were made of radium body content in 2259 occupationally or otherwise exposed persons. Of these, 1768 had skeletal radiography (one or more times). In humans, the radiographic changes were, in decreasing order of frequency, osteolytic cortical and cancellous bone destruction, bone sclerosis, pathological fracture, and avascular necrosis of bone. In beagles, osteolytic destruction and pathological fractures were common, avascular necrosis was not observed, but there was frequently cortical thickening and new-bone formation in cancellous bone. In both population groups, there was a high incidence of bone sarcoma. In the beagles, one high-dosage group numbering 38 dogs had 49 malignant bone tumors. Among the 2259 measured persons, there were 60 who had bone sarcoma, and 29 who had cancer of the mastoids or paranasal sinuses. No significant skeletal effects have been diagnosed radiologically in persons with systemic intakes of /sup 226/Ra or /sup 228/Ra below about 10 ..mu..Ci or with skeletal doses below about 100 rad. In humans, the lowest skeletal dose at which a bone sarcoma has been diagnosed is 890 rad, and the lowest intake associated with a bone sarcoma is 96 ..integral..Ci /sup 226/Ra or about 1.7 ..mu..Ci per kg body weight.

In vivo analysis of biocompatibility and vascularization of the synthetic bone grafting substitute NanoBone.

Science.gov (United States)

Abshagen, K; Schrodi, I; Gerber, T; Vollmar, B

2009-11-01

One of the major challenges in the application of bone substitutes is adequate vascularization and biocompatibility of the implant. Thus, the temporal course of neovascularization and the microvascular inflammatory response of implants of NanoBone (fully synthetic nanocrystalline bone grafting material) were studied in vivo by using the mouse dorsal skinfold chamber model. Angiogenesis, microhemodynamics, and leukocyte-endothelial cell interaction were analyzed repetitively after implantation in the center and in the border zone of the implant up to 15 days. Both NanoBone granules and plates exhibited high biocompatibility comparable to that of cancellous bone, as indicated by a lack of venular leukocyte activation after implantation. In both synthetic NanoBone groups, signs of angiogenesis could be observed even at day 5 after implantation, whereas granules showed higher functional vessel density compared with NanoBone plates. The angiogenic response of the cancellous bone was markedly accelerated in the center of the implant tissue. Histologically, implant tissue showed an ingrowth of vascularized fibrous tissue into the material combined with an increased number of foreign-body giant cells. In conclusion, NanoBone, particularly in granular form, showed high biocompatibility and high angiogenic response, thus improving the healing of bone defects. Our results underline that, beside the composition and nanostructure, the macrostructure is also of importance for the incorporation of the biomaterial by the host tissue. (c) 2008 Wiley Periodicals, Inc.

Properties of deproteinized bone for reparation of big segmental defect in long bone

Institute of Scientific and Technical Information of China (English)

JIAN Yue-kui; TIAN Xiao-bin; LI Bo; QIU Bing; ZHOU Zuo-jia; YANG Zheng; LI Qi-hong

2008-01-01

Objective: To explore suitable scaffold material for big segmental long bone defect by studying the properties of the prepared deproteinized bone. Methods: Cancellated bone were made as 30 mm ×3 mm ×3 mm bone blocks from inferior extremity of pig femur along bone trabecula. The deproteinized bone was prepared with an improved method. Their morphological features, components, cell compatibility, mechanical and immunological properties were investigated respectively. Results: Deproteinized bone maintained natural re ticular pore system. The main organic material is collagen Ⅰand inorganic composition is hydroxyapatite. It has good mechanical properties, cell adhesion rate and histocompatibility. Conlusion: This deproteinized bone can be applicable as scaffold for reparation of big segmental defect in long bone.

Effects of the 3D bone-to-implant contact and bone stiffness on the initial stability of a dental implant: micro-CT and resonance frequency analyses.

Science.gov (United States)

Hsu, J T; Huang, H L; Tsai, M T; Wu, A Y J; Tu, M G; Fuh, L J

2013-02-01

This study investigated the effects of bone stiffness (elastic modulus) and three-dimensional (3D) bone-to-implant contact ratio (BIC%) on the primary stabilities of dental implants using micro-computed tomography (micro-CT) and resonance frequency analyses. Artificial sawbone models with five values of elastic modulus (137, 123, 47.5, 22, and 12.4 MPa) comprising two types of trabecular structure (solid-rigid and cellular-rigid) were investigated for initial implant stability quotient (ISQ), measured using the wireless Osstell resonance frequency analyzer. Bone specimens were attached to 2 mm fibre-filled epoxy sheets mimicking the cortical shell. ISQ was measured after placing a dental implant into the bone specimen. Each bone specimen with an implant was subjected to micro-CT scanning to calculate the 3D BIC% values. The similarity of the cellular type of artificial bone to the trabecular structure might make it more appropriate for obtaining accurate values of primary implant stability than solid-bone blocks. For the cellular-rigid bone models, the ISQ increased with the elastic modulus of cancellous bone. The regression correlation coefficient was 0.96 for correlations of the ISQ with the elasticity of cancellous bone and with the 3D BIC%. The initial implant stability was moderately positively correlated with the elasticity of cancellous bone and with the 3D BIC%. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Ionizing Radiation Affects Gene Expression in Mouse Skin and Bone

Science.gov (United States)

Terada, Masahiro; Tahimic, Candice; Sowa, Marianne B.; Schreurs, Ann-Sofie; Shirazi-Fard, Yasaman; Alwood, Joshua; Globus, Ruth K.

2017-01-01

Future long-duration space exploration beyond low earth orbit will increase human exposure to space radiation and microgravity conditions as well as associated risks to skeletal health. In animal studies, radiation exposure (greater than 1 Gy) is associated with pathological changes in bone structure, enhanced bone resorption, reduced bone formation and decreased bone mineral density, which can lead to skeletal fragility. Definitive measurements and detection of bone loss typically require large and specialized equipment which can make their application to long duration space missions logistically challenging. Towards the goal of developing non-invasive and less complicated monitoring methods to predict astronauts' health during spaceflight, we examined whether radiation induced gene expression changes in skin may be predictive of the responses of skeletal tissue to radiation exposure. We examined oxidative stress and growth arrest pathways in mouse skin and long bones by measuring gene expression levels via quantitative polymerase chain reaction (qPCR) after exposure to total body irradiation (IR). To investigate the effects of irradiation on gene expression, we used skin and femora (cortical shaft) from the following treatment groups: control (normally loaded, sham-irradiated), and IR (0.5 Gy 56Fe 600 MeV/n and 0.5 Gy 1H 150 MeV/n), euthanized at one and 11 days post-irradiation (IR). To determine the extent of bone loss, tibiae were harvested and cancellous microarchitecture in the proximal tibia quantified ex vivo using microcomputed tomography (microCT). Statistical analysis was performed using Student's t-test. At one day post-IR, expression of FGF18 in skin was significantly greater (3.8X) than sham-irradiated controls, but did not differ at 11 days post IR. Expression levels of other genes associated with antioxidant response (Nfe2l2, FoxO3 and Sod1) and the cell cycle (Trp53, Cdkn1a, Gadd45g) did not significantly differ between the control and IR groups

Spaceflight-induced vertebral bone loss in ovariectomized rats is associated with increased bone marrow adiposity and no change in bone formation

Science.gov (United States)

Keune, Jessica A; Philbrick, Kenneth A; Branscum, Adam J; Iwaniec, Urszula T; Turner, Russell T

2016-01-01

There is often a reciprocal relationship between bone marrow adipocytes and osteoblasts, suggesting that marrow adipose tissue (MAT) antagonizes osteoblast differentiation. MAT is increased in rodents during spaceflight but a causal relationship between MAT and bone loss remains unclear. In the present study, we evaluated the effects of a 14-day spaceflight on bone mass, bone resorption, bone formation, and MAT in lumbar vertebrae of ovariectomized (OVX) rats. Twelve-week-old OVX Fischer 344 rats were randomly assigned to a ground control or flight group. Following flight, histological sections of the second lumbar vertebrae (n=11/group) were stained using a technique that allowed simultaneous quantification of cells and preflight fluorochrome label. Compared with ground controls, rats flown in space had 32% lower cancellous bone area and 306% higher MAT. The increased adiposity was due to an increase in adipocyte number (224%) and size (26%). Mineral apposition rate and osteoblast turnover were unchanged during spaceflight. In contrast, resorption of a preflight fluorochrome and osteoclast-lined bone perimeter were increased (16% and 229%, respectively). The present findings indicate that cancellous bone loss in rat lumbar vertebrae during spaceflight is accompanied by increased bone resorption and MAT but no change in bone formation. These findings do not support the hypothesis that increased MAT during spaceflight reduces osteoblast activity or lifespan. However, in the context of ovarian hormone deficiency, bone formation during spaceflight was insufficient to balance increased resorption, indicating defective coupling. The results are therefore consistent with the hypothesis that during spaceflight mesenchymal stem cells are diverted to adipocytes at the expense of forming osteoblasts. PMID:28725730

Influence of Screw Length and Bone Thickness on the Stability of Temporary Implants

Directory of Open Access Journals (Sweden)

Daniel Jogaib Fernandes

2015-09-01

Full Text Available The purpose of this work was to study the influence of screw length and bone thickness on the stability of temporary implants. A total of 96 self-drilling temporary screws with two different lengths were inserted into polyurethane blocks (n = 66, bovine femurs (n = 18 and rabbit tibia (n = 12 with different cortical thicknesses (1 to 8 mm. Screws insertion in polyurethane blocks was assisted by a universal testing machine, torque peaks were collected by a digital torquemeter and bone thickness was monitored by micro-CT. The results showed that the insertion torque was significantly increased with the thickness of cortical bone from polyurethane (p < 0.0001, bovine (p = 0.0035 and rabbit (p < 0.05 sources. Cancellous bone improved significantly the mechanical implant stability. Insertion torque and insertion strength was successfully moduled by equations, based on the cortical/cancellous bone behavior. Based on the results, insertion torque and bone strength can be estimate in order to prevent failure of the cortical layer during temporary screw placement. The stability provided by a cortical thickness of 2 or 1 mm coupled to cancellous bone was deemed sufficient for temporary implants stability.

The effect of bone marrow aspirate, bone graft and collagen composites on fixation of bone implants

DEFF Research Database (Denmark)

Babiker, Hassan; Ding, Ming; Overgaard, Søren

2007-01-01

 Introduction: Replacement of extensive local bone loss especially in revision joint arthroplasties is a significant clinical challenge. Autogenous and allogenic cancellous bone grafts have been the gold standard in reconstructive orthopaedic surgery, but it is well known that there is morbidity...... associated with harvesting of autogenous bone graft and limitations in the quantity of bone available. Disadvantages of allograft include the risk of bacterial or viral contamination and non union as well as the potential risk of disease transmission. Alternative options are attractive and continue...... to be sought. Hydroxyapatite and collagen composites have the potential in mimicking and replacing skeletal bones. Aim: This study attempted to determine the effect of hydroxyapatite/collagen composites in the fixation of bone implants. The composites used in this study is produced by Institute of Science...

Influence of Piezosurgery on Bone Healing around Titanium Implants: A Histological Study in Rats.

Science.gov (United States)

Sirolli, Marcelo; Mafra, Carlos Eduardo Secco; Santos, Rodrigo Albuquerque Basílio Dos; Saraiva, Luciana; Holzhausen, Marinella; César, João Batista

2016-01-01

The aim of this study was to evaluate histomorphometrically the influence of two techniques of dental implant site preparation on bone healing around titanium implants. Fifteen male Wistar rats (±300 g) were used in the study. Each tibia was randomly assigned to receive the implant site preparation either with a conventional drilling technique (control - DRILL group) or with a piezoelectric device (PIEZO group). The animals were sacrificed after 30 days and then the following histomorphometric parameters were evaluated (percentage) separately for cortical and cancellous regions: proportion of mineralized tissue (PMT) adjacent to implant threads (500 μm adjacent); bone area within the threads (BA) and bone-implant contact (BIC). The results demonstrated that there were no statistically significant differences between both groups for cancellous BIC (p>0.05) and cortical PMT (p>0.05). On the other hand, a higher percentage of BA was observed in the PIEZO group in the cortical (71.50±6.91 and 78.28±4.38 for DRILL and PIEZO groups, respectively; ppiezosurgery also showed higher PMT values in the cancellous zone (9.35±5.54 and 18.72±13.21 for DRILL and PIEZO groups, respectively; ppiezosurgery was beneficial to bone healing rates in the cancellous bone region, while the drill technique produced better results in the cortical bone.

MicroCT evaluation of bone mineral density loss in human bones

International Nuclear Information System (INIS)

Nogueira, Liebert P.; Braz, Delson; Lopes, Ricardo T.; Barroso, Regina C.; Oliveira, Luis F.

2007-01-01

Bone is a connective tissue largely composed of an organic protein, collagen and the inorganic mineral hydroxyapatite [Ca 10 (PO 4 ) 6 OH 2 ], which combine to provide a mechanical and supportive role in the body. Depending on the orientation of collagen fibers, two types of bone can be distinguished: trabecular and cortical bone. Degree of mineralization is considered an important feature of bone quality. Changes in the degree of mineralization is generally due to osteoporosis, but many recent studies have already shown that alterations in degree of mineralization can occur due to a large variety of factors. The transmission X-ray microtomography is one of the most popular methods, which provides the spatial distribution of the total absorption coefficient inside the sample. The aim of this study was to investigate the suitability of using microCT as a supplementary tool for the diagnosis of the health status of human bones. Eleven samples were constructed simulating the physiological range of bone mineral density (BMD) found in cortical human bone. The samples represent healthy mixtures of swine compact bone dried at room temperature, powdered and mixed with fat (0 - 100 % by mass). The samples were imaged by a microfocus tube (Fein-Focus) with focal size of about 60 μm (±5%), and a CCD camera (0.143 mm pixel size) coupled with an intensifier tube with fluoroscope screen at the Nuclear Instrumentation Laboratory (COPPE/UFRJ), Brazil. The images were reconstructed and treated with suitable software developed at the Nuclear Instrumentation Laboratory. The mineral content in cortical bone is defined by the volume of dry, fat-free bone per unit bulk volume of the bone. The volumes were calculated from the bone density using the relationship between volume and density. The densities of fat and bone were taken to be 0.95 g.cm -3 and 1.92 g.cm -3 respectively. The correlation of the measured absorption coefficient with the mineral content in the samples was then

MicroCT evaluation of bone mineral density loss in human bones

Energy Technology Data Exchange (ETDEWEB)

Nogueira, Liebert P.; Braz, Delson; Lopes, Ricardo T. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Instrumentacao Nuclear]. E-mails: lnogueira@con.ufrj.br; Barroso, Regina C.; Oliveira, Luis F. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Inst. de Fisica]. E-mail: cely@uerj.br

2007-07-01

Bone is a connective tissue largely composed of an organic protein, collagen and the inorganic mineral hydroxyapatite [Ca{sub 10}(PO{sub 4}){sub 6}OH{sub 2}], which combine to provide a mechanical and supportive role in the body. Depending on the orientation of collagen fibers, two types of bone can be distinguished: trabecular and cortical bone. Degree of mineralization is considered an important feature of bone quality. Changes in the degree of mineralization is generally due to osteoporosis, but many recent studies have already shown that alterations in degree of mineralization can occur due to a large variety of factors. The transmission X-ray microtomography is one of the most popular methods, which provides the spatial distribution of the total absorption coefficient inside the sample. The aim of this study was to investigate the suitability of using microCT as a supplementary tool for the diagnosis of the health status of human bones. Eleven samples were constructed simulating the physiological range of bone mineral density (BMD) found in cortical human bone. The samples represent healthy mixtures of swine compact bone dried at room temperature, powdered and mixed with fat (0 - 100 % by mass). The samples were imaged by a microfocus tube (Fein-Focus) with focal size of about 60 {mu}m ({+-}5%), and a CCD camera (0.143 mm pixel size) coupled with an intensifier tube with fluoroscope screen at the Nuclear Instrumentation Laboratory (COPPE/UFRJ), Brazil. The images were reconstructed and treated with suitable software developed at the Nuclear Instrumentation Laboratory. The mineral content in cortical bone is defined by the volume of dry, fat-free bone per unit bulk volume of the bone. The volumes were calculated from the bone density using the relationship between volume and density. The densities of fat and bone were taken to be 0.95 g.cm{sup -3} and 1.92 g.cm{sup -3} respectively. The correlation of the measured absorption coefficient with the mineral content

Revascularization of calvarial, mandibular, tibial, and iliac bone grafts in rats

DEFF Research Database (Denmark)

Pinholt, E M; Solheim, E; Talsnes, O

1994-01-01

Some studies have suggested that membranous bone grafts undergo less resorption than endochondral grafts, and faster revascularization of the former has been proposed as the explanation. We studied fresh syngeneic full-thickness bone grafts from calvaria, mandibula, tibia diaphysis, and iliac bone...... implanted in the back muscles of young Lewis rats. As a measure of the quantity of cancellous bone in grafts before implantation, the ratio of the total area of soft-tissue spaces to the total area of the graft was measured histomorphometrically. Revascularization in grafts 3 weeks postoperatively...... was evaluated by deposit of 141Ce-labeled microspheres. Both the quantity of cancellous bone (before implantation) and the revascularization (3 weeks postoperatively) were greater in the mandibular and iliac bone grafts than in the calvarial and tibia diaphyseal grafts. The results suggest that the anatomical...

[Comparation on Haversian system between human and animal bones by imaging analysis].

Science.gov (United States)

Lu, Hui-Ling; Zheng, Jing; Yao, Ya-Nan; Chen, Sen; Wang, Hui-Pin; Chen, Li-Xian; Guo, Jing-Yuan

2006-04-01

To explore the differences in Haversian system between human and animal bones through imaging analysis and morphology description. Thirty-five slices grinding from human being as well as dog, pig, cow and sheep bones were observed to compare their structure, then were analysed with the researchful microscope. Plexiform bone or oeston band was not found in human bones; There were significant differences in the shape, size, location, density of Haversian system, between human and animal bones. The amount of Haversian lamella and diameter of central canal in human were the biggest; Significant differences in the central canal diameter and total area percentage between human and animal bones were shown by imaging analysis. (1) Plexiform bone and osteon band could be the exclusive index in human bone; (2) There were significant differences in the structure of Haversian system between human and animal bones; (3) The percentage of central canals total area was valuable in species identification through imaging analysis.

Effects of implant drilling parameters for pilot and twist drills on temperature rise in bone analog and alveolar bones.

Science.gov (United States)

Chen, Yung-Chuan; Hsiao, Chih-Kun; Ciou, Ji-Sih; Tsai, Yi-Jung; Tu, Yuan-Kun

2016-11-01

This study concerns the effects of different drilling parameters of pilot drills and twist drills on the temperature rise of alveolar bones during dental implant procedures. The drilling parameters studied here include the feed rate and rotation speed of the drill. The bone temperature distribution was analyzed through experiments and numerical simulations of the drilling process. In this study, a three dimensional (3D) elasto-plastic dynamic finite element model (DFEM) was proposed to investigate the effects of drilling parameters on the bone temperature rise. In addition, the FE model is validated with drilling experiments on artificial human bones and porcine alveolar bones. The results indicate that 3D DFEM can effectively simulate the bone temperature rise during the drilling process. During the drilling process with pilot drills or twist drills, the maximum bone temperature occurred in the region of the cancellous bones close to the cortical bones. The feed rate was one of the important factors affecting the time when the maximum bone temperature occurred. Our results also demonstrate that the elevation of bone temperature was reduced as the feed rate increased and the drill speed decreased, which also effectively reduced the risk region of osteonecrosis. These findings can serve as a reference for dentists in choosing drilling parameters for dental implant surgeries. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Intermittent Parathyroid Hormone Enhances Cancellous Osseointegration of a Novel Murine Tibial Implant

Science.gov (United States)

Yang, Xu; Ricciardi, Benjamin F.; Dvorzhinskiy, Aleksey; Brial, Caroline; Lane, Zachary; Bhimani, Samrath; Burket, Jayme C.; Hu, Bin; Sarkisian, Alexander M.; Ross, F. Patrick; van der Meulen, Marjolein C.H.; Bostrom, Mathias P.G.

2015-01-01

Background: Long-term fixation of uncemented joint implants requires early mechanical stability and implant osseointegration. To date, osseointegration has been unreliable and remains a major challenge in cementless total knee arthroplasty. We developed a murine model in which an intra-articular proximal tibial titanium implant with a roughened stem can be loaded through the knee joint. Using this model, we tested the hypothesis that intermittent injection of parathyroid hormone (iPTH) would increase proximal tibial cancellous osseointegration. Methods: Ten-week-old female C57BL/6 mice received a subcutaneous injection of PTH (40 μg/kg/day) or a vehicle (n = 45 per treatment group) five days per week for six weeks, at which time the baseline group was killed (n = 6 per treatment group) and an implant was inserted into the proximal part of the tibiae of the remaining mice. Injections were continued until the animals were killed at one week (n = 7 per treatment group), two weeks (n = 14 per treatment group), or four weeks (n = 17 per treatment group) after implantation. Outcomes included peri-implant bone morphology as analyzed with micro-computed tomography (microCT), osseointegration percentage and bone area fraction as shown with backscattered electron microscopy, cellular composition as demonstrated by immunohistochemical analysis, and pullout strength as measured with mechanical testing. Results: Preimplantation iPTH increased the epiphyseal bone volume fraction by 31.6%. When the data at post-implantation weeks 1, 2, and 4 were averaged for the iPTH-treated mice, the bone volume fraction was 74.5% higher in the peri-implant region and 168% higher distal to the implant compared with the bone volume fractions in the same regions in the vehicle-treated mice. Additionally, the trabecular number was 84.8% greater in the peri-implant region and 74.3% greater distal to the implant. Metaphyseal osseointegration and bone area fraction were 28.1% and 70.1% higher

[Study on preparation and physicochemical properties of surface modified sintered bone].

Science.gov (United States)

Li, Jingfeng; Zheng, Qixin; Guo, Xiaodong

2012-06-01

The aim of this study is to investigate a new method for preparing a biomimetic bone material-surface modified sintered bovine cancellous bone, and to improve its bioactivity as a tissue engineering bone. The prepared sintered bovine cancellous bones with the same size were randomly divided into two groups, immersing in 1 and 1. 5 times simulated body fluid (SBF), respectively. The three time periods of soak time were 7, 14, and 21 days. After sintered bone was dried, the surface morphology of sintered bone and surface mineralization composition were observed under scanning electron microscopy (SEM). By comparing the effect of surface modification of sintered bone materials, we chose the most ideal material and studied its pore size, the rate of the porosity, the compress and bend intensity. And then the material and the sintered bone material without surface modification were compared. The study indicated that sintered bone material immersed in SBF (1.5 times) for 14 days showed the best effect of surface modification, retaining the original physico-chemical properties of sintered bone.

Preoperative assessment of the cancellous bone mineral density of the proximal humerus using CT data

International Nuclear Information System (INIS)

Krappinger, Dietmar; Roth, Tobias; Gschwentner, Martin; Suckert, Armin; Blauth, Michael; Hengg, Clemens; Kralinger, Franz

2012-01-01

Osteoporotic fractures of the proximal humerus show an increasing incidence. Osteoporosis not only influences the fracture risk after low-energy trauma, but also affects the mechanical stability of internal fixation. Preoperative assessment of the local bone quality may be useful in the surgical treatment of patients sustaining these injuries. The aim of the present study was to present a method for the preoperative assessment of the local cancellous bone mineral density (BMD) of the proximal humerus using CT data. In the first part of the study, CT scans of 30 patients with unilateral fractures of the proximal humerus after low-energy trauma were used. The local BMD was assessed on the contralateral uninjured side. All 30 patients additionally underwent dual-emission X-ray absorptiometry (DXA) of the lumbar spine, proximal femur, and forearm of the side of the uninjured proximal humerus within 6 weeks after trauma. Three independent trauma surgeons performed measurements on the uninjured proximal humerus twice with a time interval of 4 weeks in order to assess the inter- and intraobserver reliability of the method. In the second part of the study, the local BMD of 507 patients with either proximal humerus fractures or chronic shoulder instability was assessed by a single trauma surgeon. In both parts, the average HU values in standardized ROIs of the humeral head were automatically calculated after correcting for HU values below the water equivalent. A linear calibration equation was computed for the calculation from HU to BMD using a calibration device (EFP). The intra- and interobserver reliability was high (ICC > 0.95). Correlation coefficients between the local BMD of the proximal humerus and other anatomical sites were between 0.35 (lumbar spine) and 0.64 (forearm). We found a high correlation between the local BMD and age. The BMD in the fracture group was significantly lower than in the instability group. These patients were significantly older and more

Preoperative assessment of the cancellous bone mineral density of the proximal humerus using CT data

Energy Technology Data Exchange (ETDEWEB)

Krappinger, Dietmar; Roth, Tobias; Gschwentner, Martin; Suckert, Armin; Blauth, Michael; Hengg, Clemens; Kralinger, Franz [Innsbruck Medical University, Department of Trauma Surgery and Sports Medicine, Innsbruck (Austria)

2012-03-15

Osteoporotic fractures of the proximal humerus show an increasing incidence. Osteoporosis not only influences the fracture risk after low-energy trauma, but also affects the mechanical stability of internal fixation. Preoperative assessment of the local bone quality may be useful in the surgical treatment of patients sustaining these injuries. The aim of the present study was to present a method for the preoperative assessment of the local cancellous bone mineral density (BMD) of the proximal humerus using CT data. In the first part of the study, CT scans of 30 patients with unilateral fractures of the proximal humerus after low-energy trauma were used. The local BMD was assessed on the contralateral uninjured side. All 30 patients additionally underwent dual-emission X-ray absorptiometry (DXA) of the lumbar spine, proximal femur, and forearm of the side of the uninjured proximal humerus within 6 weeks after trauma. Three independent trauma surgeons performed measurements on the uninjured proximal humerus twice with a time interval of 4 weeks in order to assess the inter- and intraobserver reliability of the method. In the second part of the study, the local BMD of 507 patients with either proximal humerus fractures or chronic shoulder instability was assessed by a single trauma surgeon. In both parts, the average HU values in standardized ROIs of the humeral head were automatically calculated after correcting for HU values below the water equivalent. A linear calibration equation was computed for the calculation from HU to BMD using a calibration device (EFP). The intra- and interobserver reliability was high (ICC > 0.95). Correlation coefficients between the local BMD of the proximal humerus and other anatomical sites were between 0.35 (lumbar spine) and 0.64 (forearm). We found a high correlation between the local BMD and age. The BMD in the fracture group was significantly lower than in the instability group. These patients were significantly older and more

Mechanical Modelling of Cancellous Bone from their Microstructure

Directory of Open Access Journals (Sweden)

Ruiz–Cervantes O.

2010-04-01

Full Text Available In this paper is established a spongy bone bidimensional models methodology for its analysis by finite element software. The models are focused to represent the bone trabecular structure by Voronoi cells, using the coordinates of the porous center, contained within the bone structure, obtained by optical microscope images. Looking for a better geometrical similarity, it was assigned a thicker transversal area in the trabecula union zone, because has been reported that this factor gives a better approximation to experimental results. To feed the finite element models, compression test has been done to trabecular specimens, taking the maximum strain and maximum stress, to obtain the elastic modulus. By means of strained specimen images analysis, it has been established the structure collapse moment. It was when the 36% of total trabeculae failed. Finally it was obtained a tissue Young modulus of 323 [MPa] and with this value, the resistance variation in function of density and trabecular architecture.

Human bone ingrowth into a porous tantalum acetabular cup

Directory of Open Access Journals (Sweden)

Gregory N. Haidemenopoulos

2017-11-01

Full Text Available Porous Tantalum is increasingly used as a structural scaffold in orthopaedic applications. Information on the mechanisms of human bone ingrowth into trabecular metal implants is rather limited. In this work we have studied, qualitatively, human bone ingrowth into a retrieved porous tantalum monoblock acetabular cup using optical microscopy, scanning electron microscopy and energy dispersive X-ray analysis. According to the results and taking into account the short operational life (4 years of the implant, bone ingrowth on the acetabular cup took place in the first two-rows of porous tantalum cells to an estimated depth of 1.5 to 2 mm. The bone material, grown inside the first raw of cells, had almost identical composition with the attached bone on the cup surface, as verified by the same Ca:P ratio. Bone ingrowth has been a gradual process starting with Ca deposition on the tantalum struts, followed by bone formation into the tantalum cells, with gradual densification of the bone tissue into hydroxyapatite. A critical step in this process has been the attachment of bone material to the tantalum struts following the topology of the porous tantalum scaffold. These results provide insight to the human bone ingrowth process into porous tantalum implants.

Validating in vivo Raman spectroscopy of bone in human subjects

Science.gov (United States)

Esmonde-White, Francis W. L.; Morris, Michael D.

2013-03-01

Raman spectroscopy can non-destructively measure properties of bone related to mineral density, mineral composition, and collagen composition. Bone properties can be measured through the skin in animal and human subjects, but correlations between the transcutaneous and exposed bone measurements have only been reported for human cadavers. In this study, we examine human subjects to collect measurements transcutaneously, on surgically exposed bone, and on recovered bone fragments. This data will be used to demonstrate in vivo feasibility and to compare transcutaneous and exposed Raman spectroscopy of bone. A commercially available Raman spectrograph and optical probe operating at 785 nm excitation are used for the in vivo measurements. Requirements for applying Raman spectroscopy during a surgery are also discussed.

Registration-based Bone Morphometry for Shape Analysis of the Bones of the Human Wrist

Science.gov (United States)

Joshi, Anand A.; Leahy, Richard M.; Badawi, Ramsey D.; Chaudhari, Abhijit J.

2015-01-01

We present a method that quantifies point-wise changes in surface morphology of the bones of the human wrist. The proposed method, referred to as Registration-based Bone Morphometry (RBM), consists of two steps: an atlas selection step and an atlas warping step. The atlas for individual wrist bones was selected based on the shortest l2 distance to the ensemble of wrist bones from a database of a healthy population of subjects. The selected atlas was then warped to the corresponding bones of individuals in the population using a non-linear registration method based on regularized l2 distance minimization. The displacement field thus calculated showed local differences in bone shape that then were used for the analysis of group differences. Our results indicate that RBM has potential to provide a standardized approach to shape analysis of bones of the human wrist. We demonstrate the performance of RBM for examining group differences in wrist bone shapes based on sex and between those of the right and left wrists in healthy individuals. We also present data to show the application of RBM for tracking bone erosion status in rheumatoid arthritis. PMID:26353369

Micro-computed tomography assessment of human alveolar bone: bone density and three-dimensional micro-architecture.

Science.gov (United States)

Kim, Yoon Jeong; Henkin, Jeffrey

2015-04-01

Micro-computed tomography (micro-CT) is a valuable means to evaluate and secure information related to bone density and quality in human necropsy samples and small live animals. The aim of this study was to assess the bone density of the alveolar jaw bones in human cadaver, using micro-CT. The correlation between bone density and three-dimensional micro architecture of trabecular bone was evaluated. Thirty-four human cadaver jaw bone specimens were harvested. Each specimen was scanned with micro-CT at resolution of 10.5 μm. The bone volume fraction (BV/TV) and the bone mineral density (BMD) value within a volume of interest were measured. The three-dimensional micro architecture of trabecular bone was assessed. All the parameters in the maxilla and the mandible were subject to comparison. The variables for the bone density and the three-dimensional micro architecture were analyzed for nonparametric correlation using Spearman's rho at the significance level of p architecture parameters were consistently higher in the mandible, up to 3.3 times greater than those in the maxilla. The most linear correlation was observed between BV/TV and BMD, with Spearman's rho = 0.99 (p = .01). Both BV/TV and BMD were highly correlated with all micro architecture parameters with Spearman's rho above 0.74 (p = .01). Two aspects of bone density using micro-CT, the BV/TV and BMD, are highly correlated with three-dimensional micro architecture parameters, which represent the quality of trabecular bone. This noninvasive method may adequately enhance evaluation of the alveolar bone. © 2013 Wiley Periodicals, Inc.

Crestal Sinus Augmentation with Recombinant Human Bone Morphogenetic Protein 2: Clinical and Radiographic Outcomes of 2-Year Pilot Trial.

Science.gov (United States)

Kuchler, Ulrike; Rudelstorfer, Claudia M; Barth, Barbara; Tepper, Gabor; Lidinsky, Dominika; Heimel, Patrick; Watzek, Georg; Gruber, Reinhard

Recombinant human bone morphogenetic protein 2 (rhBMP-2) together with an absorbable collagen carrier (ACS) was approved for augmentation of the maxillary sinus prior to implant placement. The original registration trial was based on a lateral window approach. Clinical outcomes of crestal sinus augmentation with rhBMP-2 have not been reported so far. An uncontrolled pilot trial in which seven patients with a residual maxillary height below 5 mm were enrolled to receive crestal sinus augmentation with rhBMP-2/ACS was conducted. Elevation of the sinus mucosa was performed by gel pressure. Primary endpoints were the gain in augmentation height and volume measured by computed tomography after 6 months. Evaluation of bone quality at the time of implant placement was based on histology. Secondary endpoints were the clinical and radiologic evaluation of the implants and patient satisfaction by visual analog scale (VAS) at the 2-year follow-up. Median gain in augmentation height was 7.2 mm (range 0.0 to 17.5 mm). Five patients gained at least 5 mm of bone height. Two patients with a perforation of the sinus mucosa failed to respond to rhBMP-2/ACS and underwent lateral window augmentation. The median gain in augmentation volume of the five patients was 781.3 mm³ (range 426.9 to 1,242.8 mm³). Biopsy specimens showed a cancellous network consisting of primary plexiform bone with little secondary lamellar bone. After 2 years, implants were in function with no signs of inflammation or peri-implant bone loss. Patients were satisfied with the esthetic outcomes and chewing function. This pilot clinical trial supports the original concept that rhBMP-2/ACS supports bone formation, also in crestal sinus augmentation, and emphasizes the relevance of the integrity of the sinus mucosa to predict the bone gain.

Differentiating human versus non-human bone by exploring the nutrient foramen: implications for forensic anthropology.

Science.gov (United States)

Johnson, Vail; Beckett, Sophie; Márquez-Grant, Nicholas

2017-11-01

One of the roles of a forensic anthropologist is to assist medico-legal investigations in the identification of human skeletal remains. In some instances, only small fragments of bone may be present. In this study, a non-destructive novel technique is presented to distinguish between human and non-human long bones. This technique is based on the macroscopic and computed tomography (CT) analysis of nutrient foramina. The nutrient foramen of long bone diaphyses transmits the nutrient artery which provides much of the oxygen and nutrients to the bone. The nutrient foramen and its canal were analysed in six femora and humeri of human, sheep (Ovies aries) and pig (Sus scrofa) species. The location, position and direction of the nutrient foramina were measured macroscopically. The length of the canal, angle of the canal, circumference and area of the entrance of the foramen were measured from CT images. Macroscopic analysis revealed the femora nutrient foramina are more proximal, whereas humeri foramina are more distal. The human bones and sheep humerus conform to the perceived directionality, but the pig bones and sheep femur do not. Amongst the parameters measured in the CT analysis, the angle of the canal had a discriminatory power. This study shows the potential of this technique to be used independently or complementary to other methods in distinguishing between human and non-human bone in forensic anthropology.

The effect of radiation sterilization on human transplantable bone

International Nuclear Information System (INIS)

Triantafyllou, N.; Karatzas, P.

1974-11-01

In order to study the effect of radiation sterilization on human transplantable bones, work was carried out on human and bovine bone tissue samples. Factors causing possible alterations in the mechanical structures of the preserved bone allografts were considered to be deep freezing (-35degC), lyophylization, irradiation, or a combination of lyophylization and irradiation. The latter could be shown to lower the mechanical strength of the bone. Crystal lattice of the bone did not show any alterations in x-ray diffraction pattern, following freeze drying and/or irradiation with doses up to 10 Mrad of gamma radiation. Deterioration in mechanical properties is probably due to damage to the organic phase of the bone matrix

Recent progress of the bone densitometer

International Nuclear Information System (INIS)

Tamegai, Toshiaki

1996-01-01

A Bone Densitometer is the equipment which non-invasively evaluates bone mineral such as calcium contained in the bone of human. It is widely accepted as a useful equipment for the purpose of diagnosis of the bone, especially of the osteoporosis. Human body is considered as two-component system composed of bone and soft tissue at the point of view of radiation absorption. Therefore it is necessary to eliminate soft tissue component to determine bone mineral content or density. To cancel soft tissue component, there are a few methods employed to the bone densitometers. Accordingly the bone densitometers are classified into two types. In SXA, X-ray source having effective energy of approximately 30keV is used. The measurement site of patient should be soaked in water to eliminate soft tissue component according to the theory that the linear attenuation coefficient of water is nearly equal to that of soft tissue. Therefore the difference between the intensity of X-ray transmitted through soft tissue and that of X-ray through soft tissue plus bone indicates amount of bone mineral directly under the constant water thickness condition. SXA is a very convenient method, but the necessity of water may not be desirable in the clinical use. Therefore, clinical applications of SXA are limited to peripheral site such as forearm or calcaneus. In DXA, X-ray source having dual effective energies of approximately 40keV and 80keV is used. The theory is based on the difference of intensities between X-ray transmitted through soft tissue and that of transmitted through bone. The amount of bone mineral is then estimated by the theoretical calculations. Therefore, DXA is applicable for not only spine or femur but also all sites of patients. The bone densitometers based on SXA or DXA are widely accepted as the equipments for the measurement of bone mineral. However, recently, equipments based on other theoretical method, pQCT and QUS are proposed. (J.P.N.)

Bone cement allocation analysis in artificial cancellous bone structures

Directory of Open Access Journals (Sweden)

Ivan Zderic

2017-01-01

Conclusion: The simulated leakage path seemed to be the most important adverse injection factor influencing the uniformity of cement distribution. Another adverse factor causing dispersion of this distribution was represented by the simulated bone marrow. However, the rather uniform distribution of the totally injected cement amount, considered as one unit, could be ascribed to the medium viscosity of the used cement. Finally, with its short waiting time of 45 s, the stepwise injection procedure was shown to be ineffective in preventing cement leakage.

76 FR 62422 - National Institute of Environmental Health Sciences; Cancellation of Meeting

Science.gov (United States)

2011-10-07

... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health National Institute of Environmental Health Sciences; Cancellation of Meeting Notice is hereby given of the cancellation of the Interagency Breast Cancer and Environmental Research Coordinating Committee, October 12, 2011, 1 p.m. to 3 p.m...

A murine model of human myeloma bone disease

NARCIS (Netherlands)

Garrett, I.R.; Dallas, S.; Radl, J.; Mundy, G.R.

1997-01-01

Myeloma causes a devastating and unique form of osteolytic bone disease. Although osteoclast activation is responsible for bone destruction, the precise mechanisms by which myeloma cells increase osteoclast activity have not been defined. An animal model of human myeloma bone disease mould help in

Papineau debridement, Ilizarov bone transport, and negative-pressure wound closure for septic bone defects of the tibia.

Science.gov (United States)

Karargyris, Orestis; Polyzois, Vasilios D; Karabinas, Panayiotis; Mavrogenis, Andreas F; Pneumaticos, Spyros G

2014-08-01

Ilizarov pioneered bone transport using a circular external fixator. Papineau described a staged technique for the treatment for infected pseudarthrosis of the long bones. This article presents a single-stage Papineau technique and Ilizarov bone transport, and postoperative negative-pressure wound dressing changes for septic bone defects of the tibia. We studied the files of seven patients (mean age, 32 years) with septic bone defects of the tibia treated with a Papineau technique and Ilizarov bone transport in a single stage, followed by postoperative negative-pressure wound dressing changes. All patients had septic pseudarthrosis and skin necrosis of the tibia. The technique included a single-stage extensive surgical debridement of necrotic bone, open bone grafting with cancellous bone autograft and bone transport, and postoperative negative-pressure wound dressing changes for wound closure. The mean time from the initial injury was 6 months (range, 4-8 months). The mean follow-up was 14 months (range, 10-17 months). All patients experienced successful wound healing at a mean of 29 days. Six patients experienced successful bone regeneration and union at the docking side at a mean of 6 months. One patient experienced delayed union at the docking site, which was treated with autologous cancellous bone grafting. Two patients experienced pin track infection, which was successfully treated with antibiotics and pin site dressing changes. All patients were able to return to their work and previous levels of activity, except one patient who had a stiff ankle joint and had to change his job. No patient experienced recurrence of infection, or fracture of the regenerated or transported bone segment until the period of this study. The combined Papineau and Ilizarov bone transport technique with negative-pressure wound closure provides for successful eradication of the infection, reconstruction of the bone defect, and soft-tissue closure. A single-stage surgical treatment is

Enxerto ósseo esponjoso autólogo em pequenos animais Autologous cancellous bone graft in small animals

Directory of Open Access Journals (Sweden)

Fernanda Carpi dos Santos

2004-12-01

Full Text Available O enxerto ósseo esponjoso autólogo é formado por osso trabecular, poroso e altamente celular. Visto ser de fundamental importância na cirurgia ortopédica de pequenos animais, o trabalho teve por objetivo discorrer sobre a função, locais de colheita, cuidados, formas de aplicação, indicações e contra-indicações desse enxerto. Ele estimula a formação óssea devido ao fornecimento de células vivas e fatores de crescimento, mas não possui suporte mecânico. A asa do ílio craniodorsal, úmero proximal, tíbia proximal e fêmur distal, são os locais de colheita mais utilizados em cães. A asa do ílio consiste no local mais satisfatório para gatos. Para maximizar a incorporação do enxerto com o tecido hospedeiro, devem ser tomados alguns cuidados entre a colheita e a transferência para a área receptora. Além disso, pode ser aplicado sem compressão dentro do local recipiente. A freqüência de complicações é considerada baixa.The autologous cancellous bone is formed by trabecular bone, porous, and highly cellular. Since this graft is very important in orthopedic surgery of small animals, the purpose of this paper is to describe the function, donor sites, precautions, application methods, indications, and contraindications. It stimulates the bone formation because it provides live cells and growth factors, but it did not have mechanical support. Cranial dorsal wing of the ilium, proximal humerus, proximal tibia, and distal femur are the most common harvest sites used in dogs. The wing of the ilium is the most satisfactory harvest site in cats. To maximize the graft incorporation with the tissue it is necessary to take care during the harvest and transference to recipient site. In addition, it may be put into the recipient site with no compression. The frequency of complications is considered low.

Reduced rates of non-union with modified periacetabular osteotomy using peracetic-acid sterilized cancellous allografts.

Science.gov (United States)

Wassilew, Georgi I; Janz, Viktor; Renner, Lisa; Perka, Carsten; Pruss, Axel

2016-12-01

The objective of the present study was to analyze the clinical and radiological results of periacetabular osteotomies (PAO) using Kirschner wire fixation and an allogeneic cancellous bone graft. This retrospective cohort study included 73 patients (85 PAOs). The allografts were processed from distal femur of cadaveric donors, defatted, sterilized with a peracetic-acid ethanol solution and freeze-dried. The clinical outcome, as measured by the Harris Hip Scores (HHS), the complication rate and the acetabular correction, as measured by radiological parameters, were compared. The postoperative femoral head coverage and HSS were significantly improved. Major complications occurred in five cases (6 %), but in no case did we observe a non-union or a graft-associated adverse effect. Fixation of the acetabular fragment with Kirschner wires in combination with an allogeneic cancellous bone graft is a safe method, with a low complication rate, no loss of correction and can prevent the occurrence of non-union with a high degree of probability.

Bone volume fraction and structural parameters for estimation of mechanical stiffness and failure load of human cancellous bone samples; in-vitro comparison of ultrasound transit time spectroscopy and X-ray μCT.

Science.gov (United States)

Alomari, Ali Hamed; Wille, Marie-Luise; Langton, Christian M

2018-02-01

Conventional mechanical testing is the 'gold standard' for assessing the stiffness (N mm -1 ) and strength (MPa) of bone, although it is not applicable in-vivo since it is inherently invasive and destructive. The mechanical integrity of a bone is determined by its quantity and quality; being related primarily to bone density and structure respectively. Several non-destructive, non-invasive, in-vivo techniques have been developed and clinically implemented to estimate bone density, both areal (dual-energy X-ray absorptiometry (DXA)) and volumetric (quantitative computed tomography (QCT)). Quantitative ultrasound (QUS) parameters of velocity and attenuation are dependent upon both bone quantity and bone quality, although it has not been possible to date to transpose one particular QUS parameter into separate estimates of quantity and quality. It has recently been shown that ultrasound transit time spectroscopy (UTTS) may provide an accurate estimate of bone density and hence quantity. We hypothesised that UTTS also has the potential to provide an estimate of bone structure and hence quality. In this in-vitro study, 16 human femoral bone samples were tested utilising three techniques; UTTS, micro computed tomography (μCT), and mechanical testing. UTTS was utilised to estimate bone volume fraction (BV/TV) and two novel structural parameters, inter-quartile range of the derived transit time (UTTS-IQR) and the transit time of maximum proportion of sonic-rays (TTMP). μCT was utilised to derive BV/TV along with several bone structure parameters. A destructive mechanical test was utilised to measure the stiffness and strength (failure load) of the bone samples. BV/TV was calculated from the derived transit time spectrum (TTS); the correlation coefficient (R 2 ) with μCT-BV/TV was 0.885. For predicting mechanical stiffness and strength, BV/TV derived by both μCT and UTTS provided the strongest correlation with mechanical stiffness (R 2 =0.567 and 0.618 respectively) and

Scientific journal cancellations

CERN Multimedia

The Library

2001-01-01

Earlier this year the Scientific Information Policy Board (SIPB) requested the Library and the Working Group for Acquisitions to revise the current printed journal collection in order to cancel those titles that are less required. Savings could then be used for the development of other collections and particularly electronic resources needed to support CERN current research activities. A list of proposed cancellations was drawn and posted on the Library web pages: http://library.cern.ch/library_general/cancel.html The SIPB invites every one to check if any of the titles are of importance to their work, in which case you are invited to inform the Library before the 25th of September by sending an e-mail to: eliane.chaney@cern.ch Titles not reconsidered by the users will be cancelled by the end of the year. Thank you, The Library

Assessment of bone quality in the isolated femoral head for intracapsular fractures of the femoral head. Analysis of bone architecture using micro-CT and pQCT, and comparison with extracapsular fractures

International Nuclear Information System (INIS)

Sando, Masaru

2003-01-01

Block sections were prepared from the five locations, central portion, superior portion, inferior portion, anterior portion, and posterior portion, of the region around the fracture of the femoral head isolated from 21 patients (16 patients with intracapsular fracture, 5 patients with extracapsular fracture). Cancellous bone microstructure, cortical bone thickness, and bone density were evaluated and analyzed for differences in the mechanism from which intracapsular versus extracapsular fracture and fragility developed. The method of evaluating the bone architecture differed from conventional bone histomorphometry of hard tissues and involved non-invasive micro-CT measurements, while the bone density was measured by peripheral quantitative computed topography (pQCT). The results indicate that in comparison to patients with extracapsular fractures, patients with intracapsular fractures showed significant decreases in the trabecular thickness of superior and posterior portions in the cancellous bone. The cortical bone thickness was significantly decreased in the superior portion. Bone density was significantly decreased in the superior portion, while in the extracapsular fracture group density tended to be lower in the inferior, anterior, and posterior portions, although this was not statistically significant. Although there have been previous studies on the bone quality of the femoral head isolated from intracapsular fracture of the femoral head, most reports are of two-dimensional analysis of coronal sections. As far as we are aware, there have been no previous reports comparing individual locations to extracapsular fractures. In view of the various reports that bone density is lower in the extracapsular fracture compared to the intracapsular fracture, we speculate that extracapsular fracture results from the effects of external forces on decreased bone density, while in the intracapsular fracture type, thinning of the superior portion of the cortical bone creates

Optimizing Segmental Bone Regeneration Using Functionally Graded Scaffolds

Science.gov (United States)

2012-10-01

mechanical strength (130– 190 MPa).4 Cancellous bone accounts for the other 20% of the total bone mass and is highly porous (50%–90%), with *10% of the...bionanotechnology. Adv Mater 18, 1345, 2006. 96. Drury , J.L., and Mooney, D.J. Hydrogels for tissue engi- neering: scaffold design variables and applications. Bio

Bone marrow blood vessel ossification and "microvascular dead space" in rat and human long bone.

Science.gov (United States)

Prisby, Rhonda D

2014-07-01

Severe calcification of the bone microvascular network was observed in rats, whereby the bone marrow blood vessels appeared ossified. This study sought to characterize the magnitude of ossification in relation to patent blood vessels and adipocyte content in femoral diaphyses. Additionally, this study confirmed the presence of ossified vessels in patients with arteriosclerotic vascular disease and peripheral vascular disease and cellulitis. Young (4-6 month; n=8) and old (22-24 month; n=8) male Fischer-344 rats were perfused with barium sulfate to visualize patent bone marrow blood vessels. Femoral shafts were processed for bone histomorphometry to quantify ossified (Goldner's Trichrome) and calcified (Alizarin Red) vessels. Adipocyte content was also determined. Additional femora (n=5/age group) were scanned via μCT to quantify microvascular ossification. Bone marrow blood vessels from the rats and the human patients were also isolated and examined via microscopy. Ossified vessels (rats and humans) had osteocyte lacunae on the vessel surfaces and "normal" vessels were transitioning into bone. The volume of ossified vessels was 4800% higher (pnecrosis. Progression of bone microvascular ossification may provide the common link associated with age-related changes in bone and bone marrow. The clinical implications may be evident in the difficulties treating bone disease in the elderly. Copyright © 2014 Elsevier Inc. All rights reserved.

78 FR 24224 - National Institute of Allergy and Infectious Diseases; Cancellation of Meeting

Science.gov (United States)

2013-04-24

... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health National Institute of Allergy and Infectious Diseases; Cancellation of Meeting Notice is hereby given of the cancellation of the AIDS Research Advisory Committee, NIAID, June 05, 2013, 8:00 a.m. to June 05, 2013, 5:00 p.m., National...

Inca - interparietal bones in neurocranium of human skulls in central India.

Science.gov (United States)

Marathe, Rr; Yogesh, As; Pandit, Sv; Joshi, M; Trivedi, Gn

2010-01-01

Inca bones are accessory bones found in neurocranium of human skulls. Occurrence of Inca bones is rare as compared to other inter sutural bones such as wormian bones. These Inca ossicles are regarded as variants of the normal. The reporting of such occurrences is inadequate from Central India. To find the incidence of Inca variants in Central India. In the present study, 380 dried adult human skulls were examined. All specimen samples were procured from various Medical colleges of Central India. They were analyzed for gross incidence, sexual dimorphism and number of fragments of Inca bones. Gross incidence of Inca bones was found to be 1.315 %. Incidence rate was higher in male skulls than female skulls (male: 1.428%; female: 1.176%). The Inca bones frequently occurred signally. Out of the five observed Inca ossicles, two were fragmented. This data gives idea regarding gross incidence, sexual dimorphism and number of fragments of Inca bones in neurocranium of human skulls from Central India. The knowledge of this variable is useful for neurosurgeons, anthropologists and radiologists.

Engineering bone tissue from human embryonic stem cells

OpenAIRE

Marolt, Darja; Campos, Iván Marcos; Bhumiratana, Sarindr; Koren, Ana; Petridis, Petros; Zhang, Geping; Spitalnik, Patrice F.; Grayson, Warren L.; Vunjak-Novakovic, Gordana

2012-01-01

In extensive bone defects, tissue damage and hypoxia lead to cell death, resulting in slow and incomplete healing. Human embryonic stem cells (hESC) can give rise to all specialized lineages found in healthy bone and are therefore uniquely suited to aid regeneration of damaged bone. We show that the cultivation of hESC-derived mesenchymal progenitors on 3D osteoconductive scaffolds in bioreactors with medium perfusion leads to the formation of large and compact bone constructs. Notably, the i...

Antimicrobial photodynamic inactivation of Staphylococcus aureus biofilms in bone specimens using methylene blue, toluidine blue ortho and malachite green: An in vitro study.

Science.gov (United States)

Rosa, Luciano Pereira; da Silva, Francine Cristina; Nader, Sumaia Alves; Meira, Giselle Andrade; Viana, Magda Souza

2015-05-01

To evaluate the in vitro effectiveness of APDI with a 660 nm laser combined with methylene blue (MB), toluidine blue ortho (TBO) and malachite green (MG) dyes to inactivate Staphylococcus aureus (ATCC 25923) biofilms in compact and cancellous bone specimens. Eighty specimens of compact and 80 of cancellous bone were contaminated with a standard suspension of the microorganism and incubated for 14 days at 37°C to form biofilms. After this period, the specimens were divided into groups (n=10) according to established treatment: PS-L- (control - no treatment); PSmb+L-, PStbo+L-, PSmg+L- (only MB, TBO or MG for 5 min in the dark); PS-L+ (only laser irradiation for 180 s); and APDImb, APDItbo and APDImg (APDI with MB, TBO or MG for 180 s). The findings were statistically analyzed by ANOVA at 5% significance levels. All experimental treatments showed significant reduction of log CFU/mL S. aureus biofilms when compared with the control group for compact and cancellous bones specimens; the APDI group's treatment was more effective. The APDI carried out for the compact specimens showed better results when compared with cancellous specimens at all times of application. For the group of compact bone, APDImg showed greater reductions in CFU/mL (4.46 log 10). In the group of cancellous bone, the greatest reductions were found in the APDImb group (3.06 log 10). APDI with methylene blue, toluidine blue ortho and malachite green dyes and a 660 nm laser proved to be effective in the inactivation of S. aureus biofilms formed in compact and cancellous bone. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bone Marrow Blood Vessel Ossification and “Microvascular Dead Space” in Rat and Human Long Bone

Science.gov (United States)

Prisby, Rhonda D.

2014-01-01

Severe calcification of the bone microvascular network was observed in rats, whereby the bone marrow blood vessels appeared ossified. This study sought to characterize the magnitude of ossification in relation to patent blood vessels and adipocyte content in femoral diaphyses. Additionally, this study confirmed the presence of ossified vessels in patients with arteriosclerotic vascular disease and peripheral vascular disease and cellulitis. Young (4–6 mon; n=8) and old (22–24 mon; n=8) male Fischer-344 rats were perfused with barium sulfate to visualize patent bone marrow blood vessels. Femoral shafts were processed for bone histomorphometry to quantify ossified (Goldner’s Trichrome) and calcified (Alizarin Red) vessels. Adipocyte content was also determined. Additional femora (n=5/age group) were scanned via µCT to quantify microvascular ossification. Bone marrow blood vessels from rats and the human patients were also isolated and examined via microscopy. Ossified vessels (rats and humans) had osteocyte lacunae on the vessel surfaces and “normal” vessels were transitioning into bone. The volume of ossified vessels was 4800% higher (p necrosis. The progression of bone microvascular ossification may provide the common link associated with age-related changes in bone and bone marrow. The clinical implications may be evident in the difficulties treating bone disease in the elderly. PMID:24680721

Clinical trial and in-vitro study comparing the efficacy of treating bony lesions with allografts versus synthetic or highly-processed xenogeneic bone grafts

DEFF Research Database (Denmark)

Kubosch, Eva Johanna; Bernstein, Anke; Wolf, Laura

2016-01-01

BACKGROUND: Our study aim was to compare allogeneic cancellous bone (ACB) and synthetic or highly-processed xenogeneic bone substitutes (SBS) in the treatment of skeletal defects in orthopedic surgery. METHODS: 232 patients treated for bony lesions with ACB (n = 116) or SBS (n = 116) within a 10......-year time period were included in this case-control study. Furthermore, both materials were seeded with human osteoblasts (hOB, n = 10) and analyzed by histology, for viability (AlamarBlue®) and protein expression activity (Luminex®). RESULTS: The complication rate was 14.2 %, proportion of defects....... Histological examination revealed similar bone structures, whereas cell remnants were apparent only in the allografts. Both materials were biocompatible in-vitro, and seeded with human osteoblasts. The cells remained vital over the 3-week culture period and produced microscopically typical bone matrix. We...

30 CFR 250.181 - When may the Secretary cancel my lease and when am I compensated for cancellation?

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When may the Secretary cancel my lease and when... may the Secretary cancel my lease and when am I compensated for cancellation? If the Secretary cancels.... Section 250.185 states conditions under which you will receive no compensation. The Secretary may cancel a...

Scapular Free Vascularised Bone Flaps for Mandibular Reconstruction: Are Dental Implants Possible?

Directory of Open Access Journals (Sweden)

Martin Lanzer

2015-09-01

Full Text Available Objectives: Free fibula flap remains the flap of choice for reconstruction of mandibular defects. If free fibula flap is not possible, the subscapular system of flaps is a valid option. In this study, we evaluated the possibility of dental implant placement in patients receiving a scapular free flap for oromandibular reconstruction. Material and Methods: We retrospectively reviewed 10 patients undergoing mandible reconstruction with a subscapular system free-tissue (lateral border of the scapula transfer at the University Hospital Zürich between January 1, 2010 and January 1, 2013. Bone density in cortical and cancellous bone was measured in Hounsfield units (HU. Changes of bone density, height and width were analysed using IBM SPSS Statistics 22. Comparisons of bone dimensions as well as bone density were performed using a chi-square test. Results: Ten patients were included. Implantation was conducted in 50%. However, all patients could have received dental implants considering bone stock. Loss of bone height and width were significant (P < 0.001. There was a statistical significant increase in bone density in cortical (P < 0.001 and cancellous (P = 0.004 bone. Conclusions: Dental implants are possible after scapular free flap reconstruction of oromandibular defects. Bone height and width were reduced, while bone density increased with time.

Osteocytes, not Osteoblasts or Lining Cells, are the Main Source of the RANKL Required for Osteoclast Formation in Remodeling Bone.

Directory of Open Access Journals (Sweden)

Jinhu Xiong

Full Text Available The cytokine receptor activator of nuclear factor kappa B ligand (RANKL, encoded by the Tnfsf11 gene, is essential for osteoclastogenesis and previous studies have shown that deletion of the Tnfsf11 gene using a Dmp1-Cre transgene reduces osteoclast formation in cancellous bone by more than 70%. However, the Dmp1-Cre transgene used in those studies leads to recombination in osteocytes, osteoblasts, and lining cells making it unclear whether one or more of these cell types produce the RANKL required for osteoclast formation in cancellous bone. Because osteoblasts, osteocytes, and lining cells have distinct locations and functions, distinguishing which of these cell types are sources of RANKL is essential for understanding the orchestration of bone remodeling. To distinguish between these possibilities, we have now created transgenic mice expressing the Cre recombinase under the control of regulatory elements of the Sost gene, which is expressed in osteocytes but not osteoblasts or lining cells in murine bone. Activity of the Sost-Cre transgene in osteocytes, but not osteoblast or lining cells, was confirmed by crossing Sost-Cre transgenic mice with tdTomato and R26R Cre-reporter mice, which express tdTomato fluorescent protein or LacZ, respectively, only in cells expressing the Cre recombinase or their descendants. Deletion of the Tnfsf11 gene in Sost-Cre mice led to a threefold decrease in osteoclast number in cancellous bone and increased cancellous bone mass, mimicking the skeletal phenotype of mice in which the Tnfsf11 gene was deleted using the Dmp1-Cre transgene. These results demonstrate that osteocytes, not osteoblasts or lining cells, are the main source of the RANKL required for osteoclast formation in remodeling cancellous bone.

Inca - interparietal bones in neurocranium of human skulls in central India

Directory of Open Access Journals (Sweden)

R R Marathe

2010-01-01

Full Text Available Inca bones are accessory bones found in neurocranium of human skulls. Occurrence of Inca bones is rare as compared to other inter sutural bones such as wormian bones. These Inca ossicles are regarded as variants of the normal. The reporting of such occurrences is inadequate from Central India. Objectives: To find the incidence of Inca variants in Central India. Materials and Methods: In the present study, 380 dried adult human skulls were examined. All specimen samples were procured from various Medical colleges of Central India. They were analyzed for gross incidence, sexual dimorphism and number of fragments of Inca bones. Results: Gross incidence of Inca bones was found to be 1.315 %. Incidence rate was higher in male skulls than female skulls (male: 1.428%; female: 1.176%. The Inca bones frequently occurred signally. Out of the five observed Inca ossicles, two were fragmented. Conclusions: This data gives idea regarding gross incidence, sexual dimorphism and number of fragments of Inca bones in neurocranium of human skulls from Central India. The knowledge of this variable is useful for neurosurgeons, anthropologists and radiologists.

Study of Cancelled Elective Surgical Operations

Directory of Open Access Journals (Sweden)

M Amrollahi

2004-07-01

Full Text Available Introduction: Cancellation of an elective operation is a very important problem, which is the cause for different types of stresses for patients and their families and results in loss of significant amount of time, money and hospital resources. Therefore, finding the main causes of operation postponement may help us to understand and reduce these problems. Material & Method: A special questionnaire was designed to gather information about different causes of operation cancellation and filled from October 23rd (Aban 1st till November 21st (Azar 30 th, 2001 (1380 in all of the teaching hospitals of Yazd university. (S.Dr Rahnemoon, Afshar, Rah Ahan, Bahman and Savaneg Sukhteghy Results were statistically evaluated.. Results: 180 of the 31437 scheduled operations had been cancelled (12.52% Majority of cases (33.3% had been cancelled due to the absence of the surgeons. This group ((Surgeons absent was the most common cause for the postponement of operations (36.7%. The secondary cause of cancellations was related to anesthetic team and operating room problems (25%, the patient’s reasons for cancellation was 16.2% and the most minimal cause of cancellation was insufficient hospital revenue (0.5%. The basis of disease or high risk patients for operation were the main causes of dysfunction of the anesthetic team (68.9% and also the first cause of cancellation. The rate of cancellation was the most in the "older than 60 years" age group. (15.4% The cancellation in women was 12.6% and in males 12.5%. Conclusion: Surgeons schedule more patients keeping in mind cancellations which occur regularly due to patients, hospital, anesthesia, and operating room problems. This over scheduling is a problem itself, so preadmission evaluation clinics are recommended to decrease the rate of cancellations thereby saving the socioeconomic resources and decreasing patient’s stress.

Effects of combined therapy of alendronate and low-intensity pulsed ultrasound on metaphyseal bone repair after osteotomy in the proximal tibia of glucocorticoid-induced osteopenia rats

Directory of Open Access Journals (Sweden)

Tetsuya Kawano

2017-12-01

Conclusions: ALN monotherapy and combined ALN and LUPUS treatment augmented BMD and stimulated cancellous bone repair with increased Runx2 expression at the osteotomy site in GIO rats. However, the combined treatment had no additional effect on cancellous bone healing compared to ALN monotherapy.

Surgery cancellations at a public hospital

Directory of Open Access Journals (Sweden)

Erika Pittelkow

2008-12-01

Full Text Available Objective: To determine the frequency of cancellation of scheduledsurgeries at a public hospital in the city of São Paulo, and to identifythe reasons of cancellation. Methods: A descriptive, exploratory,retrospective study, with quantitative analysis, of records ofprocedures cancelled and medical charts of patients whose surgerieswere cancelled, between January 2006 and July 2007. Results: Ofthe 6,149 (100% surgeries scheduled for the period surveyed, 701(11.4% were canceled and 5,448 (88.6% conducted; among thesurgeries cancelled, most were general surgeries (237/33.8% andorthopedic surgery (200/28.5%; surgeons or assistant surgeons(518/73.9% and anesthesiologists (183/26.1% were responsible forcancellations. The primary reasons for cancellation were unfavorableclinical status of patients (225/32.1%, no show up of patients(119/17.0%, change in medical management (79/11.3%, patientnot appropriately prepared (53/7.5% and lack of material (52/7.4%.Conclusions: This study enabled identifying the frequency and causesof surgical cancellations at a public hospital, so as to contribute toimproving professional performance in this area.

Preliminary result on trabecular bone score (TBS in lumbar vertebrae with experimentally altered microarchitecture

Directory of Open Access Journals (Sweden)

M. Di Stefano

2013-01-01

Full Text Available The aim of this preliminary research is to investigate the reliability of a new qualitative parameter, called Trabecular Bone Score (TBS, recently proposed for evaluating the microarchitectural arrangement of cancellous bone in scans carried out by dual energy X-ray absorptiometry (DXA. Vertebral bodies of 15 fresh samples of lumbar spines of adult pig were analysed either in basal conditions and with altered microarchitecture of the cancellous bone obtained by progressive drilling. The examined bony areas do not show changes in bone mineral density (BMD, whereas TBS values decrease with the increasing alteration of the vertebral microtrabecular structure. Our preliminary data seem to confirm the reliability of TBS as a qualitative parameter useful for evaluating the microarchitectural strength in bony areas quantitatively analysed by DXA.

20 CFR 217.27 - Effect of cancellation.

Science.gov (United States)

2010-04-01

... ANNUITY OR LUMP SUM Cancellation of Application § 217.27 Effect of cancellation. When a person cancels an application the effect is the same as though an application was never filed. When an employee cancels his or her application, any application filed by the employee's spouse is also cancelled. However, a request...

75 FR 81283 - Oncologic Drugs Advisory Committee; Cancellation

Science.gov (United States)

2010-12-27

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2010-N-0001] Oncologic Drugs Advisory Committee; Cancellation AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The meeting of the Oncologic Drugs Advisory Committee scheduled for February 9, 2011, is...

77 FR 63839 - Oncologic Drugs Advisory Committee; Cancellation

Science.gov (United States)

2012-10-17

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2012-N-0001] Oncologic Drugs Advisory Committee; Cancellation AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The meeting of the Oncologic Drugs Advisory Committee Meeting scheduled for November 8, 2012, is...

48 CFR 552.238-73 - Cancellation.

Science.gov (United States)

2010-10-01

... may cancel this contract in whole or in part by providing written notice. The cancellation will take... elects to cancel this contract, the Government will not reimburse the minimum guarantee. (End of clause) ...

Normal human bone marrow and its variations in MRI

International Nuclear Information System (INIS)

Vahlensieck, M.; Schmidt, H.M.

2000-01-01

Physiology and age dependant changes of human bone marrow are described. The resulting normal distribution patterns of active and inactive bone marrow including the various contrasts on different MR-sequences are discussed. (orig.) [de

Multilayer porous UHMWPE scaffolds for bone defects replacement.

Science.gov (United States)

Maksimkin, A V; Senatov, F S; Anisimova, N Yu; Kiselevskiy, M V; Zalepugin, D Yu; Chernyshova, I V; Tilkunova, N A; Kaloshkin, S D

2017-04-01

Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79±2%; the pore size range was 80-700μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility. Copyright © 2016 Elsevier B.V. All rights reserved.

Radiographic/morphologic investigation of a radiolucent crescent within the flexor central eminence of the navicular bone in Thoroughbreds

International Nuclear Information System (INIS)

Berry, C.R.; Pool, R.R.; Stover, S.; O'Brien, T.R.; Koblik, P.D.

1992-01-01

The source of a previously described radiolucent crescent in the flexor cortex of the distal sesamoid (navicular) bone on the palmaro45 degrees proximal-palmarodistal oblique (Pa45 degrees Pr-PaDio) clinical radiographic projection was investigated in 48 forelimb navicular bones from 24 Thoroughbreds by use of high-detail radiography and x-ray computed tomography (CT). Twenty-five of these bones also were evaluated, using microradiography and histologic examinations. Of these 25 bones, 5 had been labeled in vivo with fluorochrome markers. Tetrachrome-stained 100-microns-thick nondecalcified sections of these 5 bones were examined, using epifluorescence microscopy. A reinforcement line of compacted cancellous bone, parallel and several millimeters deep to the flexor cortex in the region of the flexor central eminence, was visualized by CT in 42 of 48 navicular bones and by microradiography in 23 of 25 navicular bones investigated. Variable degrees of compaction were observed in the cancellous bone between the flexor cortex and the reinforcement line. High-detail skyline radiographic projections and reconstructed CT images indicated a crescent-shaped lucency within the flexor central eminence of the flexor cortex in the bones in which the reinforcement line was identified, but the cancellous bone between the reinforcement line and the flexor cortex had not been compacted. The radiolucent crescent seen in the flexor central eminence of the navicular bone on the Pa45 degrees Pr-PaDiO projection was not caused by the concave defect or synovial fossa of the flexor central eminence overlying the flexor cortex, as was described

Normal epidermal growth factor receptor signaling is dispensable for bone anabolic effects of parathyroid hormone.

Science.gov (United States)

Schneider, Marlon R; Dahlhoff, Maik; Andrukhova, Olena; Grill, Jessica; Glösmann, Martin; Schüler, Christiane; Weber, Karin; Wolf, Eckhard; Erben, Reinhold G

2012-01-01

Although the bone anabolic properties of intermittent parathyroid hormone (PTH) have long been employed in the treatment of osteoporosis, the molecular mechanisms behind this action remain largely unknown. Previous studies showed that PTH increases the expression and the activity of epidermal growth factor receptor (EGFR) in osteoblasts, and activation of ERK1/2 by PTH in osteoblasts was demonstrated to induce the proteolytical release of EGFR ligands and EGFR transactivation. However, conclusive evidence for an important role of the EGFR system in mediating the anabolic actions of intermittent PTH on bone in vivo is lacking. Here, we evaluated the effects of intermittent PTH on bone in Waved-5 (Wa5) mice which carry an antimorphic Egfr allele whose product acts as a dominant negative receptor. Heterozygous Wa5 females and control littermates received a subcutaneous injection of PTH (80 μg/kg) or buffer on 5 days per week for 4 weeks. Wa5 mice had slightly lower total bone mineral density (BMD), but normal cancellous bone volume and turnover in the distal femoral metaphysis. The presence of the antimorphic Egfr allele neither influenced the PTH-induced increase in serum osteocalcin nor the increases in distal femoral BMD, cortical thickness, cancellous bone volume, and cancellous bone formation rate. Similarly, the PTH-induced rise in lumbar vertebral BMD was unchanged in Wa5 relative to wild-type mice. Wa5-derived osteoblasts showed considerably lower basal extracellular signal-regulated kinase 1/2 (ERK1/2) activation as compared to control osteoblasts. Whereas activation of ERK1/2 by the EGFR ligand amphiregulin was largely blocked in Wa5 osteoblasts, treatment with PTH induced ERK1/2 activation comparable to that observed in control osteoblasts, relative to baseline levels. Our data indicate that impairment of EGFR signaling does not affect the anabolic action of intermittent PTH on cancellous and cortical bone. Copyright © 2011. Published by Elsevier Inc.

Stereological measures of trabecular bone structure: comparison of 3D micro computed tomography with 2D histological sections in human proximal tibial bone biopsies

DEFF Research Database (Denmark)

Thomsen, Jesper Skovhus; Laib, A.; Koller, B.

2005-01-01

Stereology applied on histological sections is the 'gold standard' for obtaining quantitative information on cancellous bone structure. Recent advances in micro computed tomography (microCT) have made it possible to acquire three-dimensional (3D) data non-destructively. However, before the 3D...... methods can be used as a substitute for the current 'gold standard' they have to be verified against the existing standard. The aim of this study was to compare bone structural measures obtained from 3D microCT data sets with those obtained by stereology performed on conventional histological sections...... tibial metaphysis. The biopsies were embedded in methylmetacrylate before microCT scanning in a Scanco microCT 40 scanner at a resolution of 20 x 20 x 20 microm3, and the 3D data sets were analysed with a computer program. After microCT scanning, 16 sections were cut from the central 2 mm of each biopsy...

Bone dosimetry using synthetic images to represent trabecular bones of five regions of the human body

Energy Technology Data Exchange (ETDEWEB)

Lima Filho, Jose de M. [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil); Vieira, Jose W. [Escola Politecnica de Pernambuco (POLI). Universidade de Pernambuco (UPE), Recife, PE (Brazil); Lima, Vanildo J. de M., E-mail: vjr@ufpe.br [Departamento de Anatomia. Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Lima, Lindeval F., E-mail: lindeval@dmat.ufrr.br [Departamento de Matematica (DMAT). Universidade Federal de Roraima (UFRR), Boa Vista, RR (Brazil); Lima, Fernando R.A., E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares (CRCN/NE-CNEN-PE), Recife, PE (Brazil); Vasconcelos, Wagner E. de [Departamento de Energia Nuclear (DEN). Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

2011-07-01

One of the greatest challenges in numerical dosimetry of ionizing radiation is to estimate the absorbed dose by bone tissue in the human body. The bone tissues of greater radiosensitivity are the red bone marrow (RBM), that consist of the hematopoietic cells, located within the trabecular bones, and the bone surface cells (BSC), called osteogenic cells. The report 70 of the ICRP lists five spongiosa regions with their respective volume percent of trabecular bone: ribs (also contemplating the clavicles and sternum), spine, long bones, pelvis and skull (also contemplating mandible). The Grupo de Pesquisa em Dosimetria Numerica (GDN/CNPq) has been built exposure computational models (ECMs) based on voxel phantoms and EGSnrc Monte Carlo code. To estimate the energy deposited in the RBM and in the BSC of a phantom, the GDN/CNPq has used a method based on micro-CT images of the five trabecular regions mentioned above. These images were provided by other research institutes and were obtained from scan of bone samples of adult. Here is the greatest difficulty in reproducing this method: besides the need for bone images of real people with micrometer resolution, the distribution of bone marrow in the human body, according to ICRP 70, varies with age. This article presents some proposals of the GDN/CNPQ for replacing in the ECMs the micro-CT images by images synthesized by the computer, based on Monte Carlo sampling. (author)

Bone dosimetry using synthetic images to represent trabecular bones of five regions of the human body

International Nuclear Information System (INIS)

Lima Filho, Jose de M.; Vieira, Jose W.; Lima, Vanildo J. de M.; Lima, Lindeval F.; Lima, Fernando R.A.; Vasconcelos, Wagner E. de

2011-01-01

One of the greatest challenges in numerical dosimetry of ionizing radiation is to estimate the absorbed dose by bone tissue in the human body. The bone tissues of greater radiosensitivity are the red bone marrow (RBM), that consist of the hematopoietic cells, located within the trabecular bones, and the bone surface cells (BSC), called osteogenic cells. The report 70 of the ICRP lists five spongiosa regions with their respective volume percent of trabecular bone: ribs (also contemplating the clavicles and sternum), spine, long bones, pelvis and skull (also contemplating mandible). The Grupo de Pesquisa em Dosimetria Numerica (GDN/CNPq) has been built exposure computational models (ECMs) based on voxel phantoms and EGSnrc Monte Carlo code. To estimate the energy deposited in the RBM and in the BSC of a phantom, the GDN/CNPq has used a method based on micro-CT images of the five trabecular regions mentioned above. These images were provided by other research institutes and were obtained from scan of bone samples of adult. Here is the greatest difficulty in reproducing this method: besides the need for bone images of real people with micrometer resolution, the distribution of bone marrow in the human body, according to ICRP 70, varies with age. This article presents some proposals of the GDN/CNPQ for replacing in the ECMs the micro-CT images by images synthesized by the computer, based on Monte Carlo sampling. (author)

Bone blood flow and metabolism in humans

DEFF Research Database (Denmark)

Heinonen, Ilkka; Kemppainen, Jukka; Kaskinoro, Kimmo

2012-01-01

Human bone blood flow and metabolism during physical exercise remains poorly characterised. In the present study we measured femoral bone blood flow and glucose uptake in young healthy subjects by positron emission tomography in three separate protocols. In six women, blood flow was measured...... in femoral bone at rest and during one leg intermittent isometric exercise with increasing exercise intensities. In nine men, blood flow in femur was determined at rest and during dynamic one leg exercise, and two other physiological perturbations: moderate systemic hypoxia (14 O(2) ) at rest and during...... exercise, and during intra-femoral infusion of high-dose adenosine. Bone glucose uptake was measured at rest and during dynamic one leg exercise in five men. The results indicate that isometric exercise increased femoral bone blood flow from rest (1.8 ± 0.6 ml/100g/min) to low intensity exercise (4.1 ± 1...

Depth measurements of drilled holes in bone by laser triangulation for the field of oral implantology

Science.gov (United States)

Quest, D.; Gayer, C.; Hering, P.

2012-01-01

Laser osteotomy is one possible method of preparing beds for dental implants in the human jaw. A major problem in using this contactless treatment modality is the lack of haptic feedback to control the depth while drilling the implant bed. A contactless measurement system called laser triangulation is presented as a new procedure to overcome this problem. Together with a tomographic picture the actual position of the laser ablation in the bone can be calculated. Furthermore, the laser response is sufficiently fast as to pose little risk to surrounding sensitive areas such as nerves and blood vessels. In the jaw two different bone structures exist, namely the cancellous bone and the compact bone. Samples of both bone structures were examined with test drillings performed either by laser osteotomy or by a conventional rotating drilling tool. The depth of these holes was measured using laser triangulation. The results and the setup are reported in this study.

The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone

DEFF Research Database (Denmark)

Ding, Ming; Danielsen, Carl C; Overgaard, Søren

2010-01-01

The effects of glucocorticoid on microarchitecture, collagen, mineral and mechanical properties of sheep femur cortical bone – Validation of large animal model for tissue engineering and biomaterial research Ming Ding,1* Carl Christian Danielsen,2 Søren Overgaard1 1Orthopaedic Research Laboratory......, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Odense C, Denmark 2Department of Connective Tissue Biology, Institute of Anatomy, University of Aarhus, Aarhus C, Denmark Osteopenia in sheep has been successfully induced...... by glucocorticoid treatment and the changes in properties of cancellous bone were comparable with those observed in humans after long-term glucocorticoid treatment. However, the influence on cortical bone has not been thoroughly elucidated. This study aimed to investigate the influence of glucocorticoid on sheep...

The Anabolic Effect of PTH on Bone is Attenuated by Simultaneous Glucocorticoid Treatment

DEFF Research Database (Denmark)

Oxlund, Hans; Ørtoft, Gitte; Thomsen, Jesper Skovhus

2006-01-01

. The pronounced anabolic effect of PTH injections on the endocortical and trabecular bone surfaces and less pronounced anabolic effect on periosteal surfaces were partially inhibited, but not prevented, by simultaneous GC treatment in old rats. Both cortical and cancellous bone possessed full mechanical...

Methods and theory in bone modeling drift: comparing spatial analyses of primary bone distributions in the human humerus.

Science.gov (United States)

Maggiano, Corey M; Maggiano, Isabel S; Tiesler, Vera G; Chi-Keb, Julio R; Stout, Sam D

2016-01-01

This study compares two novel methods quantifying bone shaft tissue distributions, and relates observations on human humeral growth patterns for applications in anthropological and anatomical research. Microstructural variation in compact bone occurs due to developmental and mechanically adaptive circumstances that are 'recorded' by forming bone and are important for interpretations of growth, health, physical activity, adaptation, and identity in the past and present. Those interpretations hinge on a detailed understanding of the modeling process by which bones achieve their diametric shape, diaphyseal curvature, and general position relative to other elements. Bone modeling is a complex aspect of growth, potentially causing the shaft to drift transversely through formation and resorption on opposing cortices. Unfortunately, the specifics of modeling drift are largely unknown for most skeletal elements. Moreover, bone modeling has seen little quantitative methodological development compared with secondary bone processes, such as intracortical remodeling. The techniques proposed here, starburst point-count and 45° cross-polarization hand-drawn histomorphometry, permit the statistical and populational analysis of human primary tissue distributions and provide similar results despite being suitable for different applications. This analysis of a pooled archaeological and modern skeletal sample confirms the importance of extreme asymmetry in bone modeling as a major determinant of microstructural variation in diaphyses. Specifically, humeral drift is posteromedial in the human humerus, accompanied by a significant rotational trend. In general, results encourage the usage of endocortical primary bone distributions as an indicator and summary of bone modeling drift, enabling quantitative analysis by direction and proportion in other elements and populations. © 2015 Anatomical Society.

DNA and bone structure preservation in medieval human skeletons.

Science.gov (United States)

Coulson-Thomas, Yvette M; Norton, Andrew L; Coulson-Thomas, Vivien J; Florencio-Silva, Rinaldo; Ali, Nadir; Elmrghni, Samir; Gil, Cristiane D; Sasso, Gisela R S; Dixon, Ronald A; Nader, Helena B

2015-06-01

Morphological and ultrastructural data from archaeological human bones are scarce, particularly data that have been correlated with information on the preservation of molecules such as DNA. Here we examine the bone structure of macroscopically well-preserved medieval human skeletons by transmission electron microscopy and immunohistochemistry, and the quantity and quality of DNA extracted from these skeletons. DNA technology has been increasingly used for analyzing physical evidence in archaeological forensics; however, the isolation of ancient DNA is difficult since it is highly degraded, extraction yields are low and the co-extraction of PCR inhibitors is a problem. We adapted and optimised a method that is frequently used for isolating DNA from modern samples, Chelex(®) 100 (Bio-Rad) extraction, for isolating DNA from archaeological human bones and teeth. The isolated DNA was analysed by real-time PCR using primers targeting the sex determining region on the Y chromosome (SRY) and STR typing using the AmpFlSTR(®) Identifiler PCR Amplification kit. Our results clearly show the preservation of bone matrix in medieval bones and the presence of intact osteocytes with well preserved encapsulated nuclei. In addition, we show how effective Chelex(®) 100 is for isolating ancient DNA from archaeological bones and teeth. This optimised method is suitable for STR typing using kits aimed specifically at degraded and difficult DNA templates since amplicons of up to 250bp were successfully amplified. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Age variations in the properties of human tibial trabecular bone and cartilage

DEFF Research Database (Denmark)

Ding, Ming

2000-01-01

, such as apparent, apparent ash and collagen densities of human tibial trabecular bone have significant relationships with age. Tissue density and mineral concentration remain constant throughout life. Trabecular bone is tougher in the younger age, i.e. fracture requires more energy. Collagen density was the single......Initiated and motivated by clinical and scientific problems such as age-related bone fracture, prosthetic loosening, bone remodeling, and degenerative bone diseases, much significant research on the properties of trabecular bone has been carried out over the last two decades. This work has mainly...... focused on the central vertebral trabecular bone, while little is known about age-related changes in the properties of human peripheral (tibial) trabecular bone. Knowledge of the properties of peripheral (tibial) trabecular bone is of major importance for the understanding of degenerative diseases...

Closing the medullary canal after retrograde nail removal using a bioabsorbable bone plug: technical tip

NARCIS (Netherlands)

Schepers, T.; Vogels, L. M. M.

2012-01-01

We describe a simple technique for closure of the intra-articular opening after the removal of a retrograde femur nail. With the use of a gelatine bioabsorbable bone plug the medullary canal is closed, reducing leakage of blood and cancellous bone particles from the bone into the knee joint

First forensic records of termite activity on non-fossilized human bones in Brazil

Directory of Open Access Journals (Sweden)

R. A. Queiroz

Full Text Available Abstract The aim of this study was to describe the first records of termite activity on non-fossilized human bones in Brazil. The cases reported in this study resulted from forensic analysis of six human skeletons found in northeastern Brazil between 2012 and 2014. Traces of tunnels and nests commonly produced by termites were found on several human bone surfaces as well as the specimens and characteristic signs of osteophagic activity. In four cases, the species were identified: Amitermes amifer Silvestri, 1901, Nasutitermes corniger (Motschulsky, 1855 (on two skeletons, and Microcerotermes indistinctus Mathews, 1977. In two other cases, the activity of termites on bone surfaces was evidenced by remains of nests and tunnels produced by these insects. At least in the samples of human remains available for this report, the number of termites collected was greater on bones found during autumn, the rainy season in the Northeast of Brazil. The human bones examined showed termites like insects with lots of strength at bone degradation, capable of continuing the process of decomposition of human remains even in completely skeletonized bodies.

Polyetheretherketone (PEEK) cage filled with cancellous allograft in anterior cervical discectomy and fusion

Science.gov (United States)

Liao, Jen-Chung; Chen, Wen-Jer; Chen, Lih-Huei

2007-01-01

From July 2004 to June 2005, 19 patients with 25 discs underwent anterior cervical discectomy and interbody fusion (ACDF) in which polyetheretherketone (PEEK) cages were filled with freeze-dried cancellous allograft bone. This kind of bone graft was made from femoral condyle that was harvested during total knee arthroplasty. Patient age at surgery was 52.9 (28–68) years. All patients were followed up at least 1 year. We measured the height of the disc and segmental sagittal angulation by pre-operative and post-operative radiographs. CT scan of the cervical spine at 1 year was used to evaluate fusion rates. Odom's criteria were used to assess the clinical outcome. All interbody disc spaces achieved successful union at 1-year follow-up. The use of a PEEK cage was found to increase the height of the disc immediately after surgery (5.0 mm pre-operatively, 7.3 mm immediately post-operatively). The final disc height was 6.2 mm, and the collapse of the disc height was 1.1 mm. The segmental lordosis also increased after surgery (2.0° pre-operatively, 6.6° immediately post-operatively), but the mean loss of lordosis correction was 3.3° at final follow-up. Seventy-four percent of patients (14/19) exhibited excellent/good clinical outcomes. Analysis of the results indicated the cancellous allograft bone-filled PEEK cage used in ACDF is a good choice for patients with cervical disc disease, and avoids the complications of harvesting iliac autograft. PMID:17639386

The relationship between 3D bone architectural parameters and elastic moduli of three orthogonal directions predicted from finite elements analysis

International Nuclear Information System (INIS)

Park, Kwan Soo; Lee, Sam Sun; Huh, Kyung Hoe; Yi, Wan Jin; Heo, Min Suk; Choi, Soon Chul

2008-01-01

To investigate the relationship between 3D bone architectural parameters and direction-related elastic moduli of cancellous bone of mandibular condyle. Two micro-pigs (Micro-pigR, PWG Genetics Korea) were used. Each pig was about 12 months old and weighing around 44 kg. 31 cylindrical bone specimen were obtained from cancellous bone of condyles for 3D analysis and measured by micro-computed tomography. Six parameters were trabecular thickness (Tb.Th), bone specific surface (BS/BV), percent bone volume (BV/TV), structure model index (SMI), degree of anisotropy (DA) and 3-dimensional fractal dimension (3DFD). Elastic moduli of three orthogonal directions (superiorinferior (SI), medial-lateral (ML), andterior-posterior (AP) direction) were calculated through finite element analysis. Elastic modulus of superior-inferior direction was higher than those of other directions. Elastic moduli of 3 orthogonal directions showed different correlation with 3D architectural parameters. Elastic moduli of SI and ML directions showed significant strong to moderate correlation with BV/TV, SMI and 3DFD. Elastic modulus of cancellous bone of pig mandibular condyle was highest in the SI direction and it was supposed that the change into plate-like structure of trabeculae was mainly affected by increase of trabeculae of SI and ML directions.

Micro-CT characterization of human trabecular bone in osteogenesis imperfecta

Science.gov (United States)

Jameson, John; Albert, Carolyne; Smith, Peter; Molthen, Robert; Harris, Gerald

2011-03-01

Osteogenesis imperfecta (OI) is a genetic syndrome affecting collagen synthesis and assembly. Its symptoms vary widely but commonly include bone fragility, reduced stature, and bone deformity. Because of the small size and paucity of human specimens, there is a lack of biomechanical data for OI bone. Most literature has focused on histomorphometric analyses, which rely on assumptions to extrapolate 3-D properties. In this study, a micro-computed tomography (μCT) system was used to directly measure structural and mineral properties in pediatric OI bone collected during routine surgical procedures. Surface renderings suggested a poorly organized, plate-like orientation. Patients with a history of bone-augmenting drugs exhibited increased bone volume fraction (BV/TV), trabecular number (Tb.N), and connectivity density (Eu.Conn.D). The latter two parameters appeared to be related to OI severity. Structural results were consistently higher than those reported in a previous histomorphometric study, but these differences can be attributed to factors such as specimen collection site, drug therapy, and assumptions associated with histomorphometry. Mineral testing revealed strong correlations with several structural parameters, highlighting the importance of a dual approach in trabecular bone testing. This study reports some of the first quantitative μCT data of human OI bone, and it suggests compelling possibilities for the future of OI bone assessment.

Methodological approach for the evaluation of homologous bone graft use in post-extractive atrophic alveolar ridges

Directory of Open Access Journals (Sweden)

B. Musante

2013-01-01

Full Text Available The aim of this study is to investigate the in vivo efficacy of Puros® cancellous particulate allograft bone in the regeneration of post-extractive sites. Twelve molar or premolar sites were selected. Seven days after minimally invasive tooth extraction, Puros® cancellous particulate allografts were inserted into the elected sites. TC Cone-Beam investigation and at 4 months from surgery; bone height and width were evaluated. Five months after surgery, biopsy samples of the regenerated sites were taken and histologically analyzed to qualitatively evaluate bone regeneration. TC analysis showed, a mean bone gain of 4.1 mm in height and 2.02 mm in width. The histological analysis of the samples showed intense bone metabolic activity with active osteoblasts on the implant surface, at the level of the native bone-graft interface and in the grafted area. The radiographic and histological analyses demonstrate an optimal bonen regeneration, both in terms of quality and quantity using Puros®.

Fat, Sugar, and Bone Health: A Complex Relationship.

Science.gov (United States)

Tian, Li; Yu, Xijie

2017-05-17

With people aging, osteoporosis is expected to increase notably. Nutritional status is a relatively easily-modified risk factor, associated with many chronic diseases, and is involved in obesity, diabetes, and coronary heart disease (CHD), along with osteoporosis. Nutrients, such as fats, sugars, and proteins, play a primary function in bone metabolism and maintaining bone health. In Western nations, diets are generally high in saturated fats, however, currently, the nutritional patterns dominating in China continue to be high in carbohydrates from starch, cereals, and sugars. Moreover, high fat or high sugar (fructose, glucose, or sucrose) impart a significant impact on bone structural integrity. Due to diet being modifiable, demonstrating the effects of nutrition on bone health can provide an approach for osteoporosis prevention. Most researchers have reported that a high-fat diet consumption is associated with bone mineral density (BMD) and, as bone strength diminishes, adverse microstructure changes occur in the cancellous bone compartment, which is involved with lipid metabolism modulation disorder and the alteration of the bone marrow environment, along with an increased inflammatory environment. Some studies, however, demonstrated that a high-fat diet contributes to achieving peak bone mass, along with microstructure, at a younger age. Contrary to these results, others have shown that a high-fructose diet consumption leads to stronger bones with a superior microarchitecture than those with the intake of a high-glucose diet and, at the same time, research indicated that a high-fat diet usually deteriorates cancellous bone parameters, and that the incorporation of fructose into a high-fat diet did not aggravate bone mass loss. High-fat/high-sucrose diets have shown both beneficial and detrimental influences on bone metabolism. Combined, these studies showed that nutrition exerts different effects on bone health. Thus, a better understanding of the regulation

Fat, Sugar, and Bone Health: A Complex Relationship

Directory of Open Access Journals (Sweden)

Li Tian

2017-05-01

Full Text Available With people aging, osteoporosis is expected to increase notably. Nutritional status is a relatively easily-modified risk factor, associated with many chronic diseases, and is involved in obesity, diabetes, and coronary heart disease (CHD, along with osteoporosis. Nutrients, such as fats, sugars, and proteins, play a primary function in bone metabolism and maintaining bone health. In Western nations, diets are generally high in saturated fats, however, currently, the nutritional patterns dominating in China continue to be high in carbohydrates from starch, cereals, and sugars. Moreover, high fat or high sugar (fructose, glucose, or sucrose impart a significant impact on bone structural integrity. Due to diet being modifiable, demonstrating the effects of nutrition on bone health can provide an approach for osteoporosis prevention. Most researchers have reported that a high-fat diet consumption is associated with bone mineral density (BMD and, as bone strength diminishes, adverse microstructure changes occur in the cancellous bone compartment, which is involved with lipid metabolism modulation disorder and the alteration of the bone marrow environment, along with an increased inflammatory environment. Some studies, however, demonstrated that a high-fat diet contributes to achieving peak bone mass, along with microstructure, at a younger age. Contrary to these results, others have shown that a high-fructose diet consumption leads to stronger bones with a superior microarchitecture than those with the intake of a high-glucose diet and, at the same time, research indicated that a high-fat diet usually deteriorates cancellous bone parameters, and that the incorporation of fructose into a high-fat diet did not aggravate bone mass loss. High-fat/high-sucrose diets have shown both beneficial and detrimental influences on bone metabolism. Combined, these studies showed that nutrition exerts different effects on bone health. Thus, a better understanding of

Is fatty acid composition of human bone marrow significant to bone health?

Science.gov (United States)

Pino, Ana María; Rodríguez, J Pablo

2017-12-16

The bone marrow adipose tissue (BMAT) is a conserved component of the marrow microenvironment, providing storage and release of energy and stabilizing the marrow extent. Also, it is recognized both the amount and quality of BMAT are relevant to preserve the functional relationships between BMAT, bone, and blood cell production. In this article we ponder the information supporting the tenet that the quality of BMAT is relevant to bone health. In the human adult the distribution of BMAT is heterogeneous over the entire skeleton, and both BMAT accumulation and bone loss come about with aging in healthy populations. But some pathological conditions which increase BMAT formation lead to bone impairment and fragility. Analysis in vivo of the relative content of saturated and unsaturated fatty acids (FA) in BMAT indicates site-related bone marrow fat composition and an association between increased unsaturation index (UI) and bone health. With aging some impairment ensues in the regulation of bone marrow cells and systemic signals leading to local chronic inflammation. Most of the bone loss diseases which evolve altered BMAT composition have as common factors aging and/or chronic inflammation. Both saturated and unsaturated FAs originate lipid species which are active mediators in the inflammation process. Increased free saturated FAs may lead to lipotoxicity of bone marrow cells. The pro-inflammatory, anti-inflammatory or resolving actions of compounds derived from long chain poly unsaturated FAs (PUFA) on bone cells is varied, and depending on the metabolism of the parent n:3 or n:6 PUFAs series. Taking together the evidence substantiate that marrow adipocyte function is fundamental for an efficient link between systemic and marrow fatty acids to accomplish specific energy or regulatory needs of skeletal and marrow cells. Further, they reveal marrow requirements of PUFAs. Copyright © 2017 Elsevier Inc. All rights reserved.

The use of lyophilised bovine bone xenograft in mandibular reconstructive surgery - an animal experimental surgery

International Nuclear Information System (INIS)

Samsudin, A.R.; Meor Kamal, M. Z.; Afifi Abu Bakar

1999-01-01

The aim of this study is to look at the effectiveness of using lyophillised bovine bone xenograft in mandibular reconstructive surgery. Six adult merino sheep underwent bilateral marginal block resection of the mandible under general anaesthesia. The defect on the right body of mandible was left alone while the similar mandibulectomy defect on the left body of mandible was reconstructed using a cortico-cancellous block of radiosterilised lyophillised bovine bone xenograft which was procured from a calve femur. The bone xenograft was fixed and immobilized using titanium mini plates and screws. All the sheep returned to the controlled grazing ground on the 7th. Postoperative day. One sheep was sacrificed every month and the mandible was retrieved for postmortem gross and microscopical histological examination. Clinical results showed no evidence of tissue rejection in the mandible of the sheep and all the wounds healed well. All sheep showed no problem with normal eating habits. Histological examination showed resorption of the xenograft very early at one month postoperative and xenograft resorption together with new host bone deposition started at 2 months postoperative and maximise at 6 months postoperative. There is also evidence showing that the cancellous portion resorp more than the cortical portion of the xenograft. In conclusion, cortico-cancellous blocks of bovine bone xenograft may be use in mandibular reconstructive surgery giving esthetically acceptable, functional, biocompatible and overall clinically predictable results

Two-wave propagation in in vitro swine distal ulna

Science.gov (United States)

Mano, Isao; Horii, Kaoru; Matsukawa, Mami; Otani, Takahiko

2015-07-01

Ultrasonic transmitted waves were obtained in an in vitro swine distal ulna specimen, which mimics a human distal radius, that consists of interconnected cortical bone and cancellous bone. The transmitted waveforms appeared similar to the fast waves, slow waves, and overlapping fast and slow waves measured in the specimen after removing the surface cortical bone (only cancellous bone). In addition, the circumferential waves in the cortical bone and water did not affect the fast and slow waves. This suggests that the fast-and-slow-wave phenomenon can be observed in an in vivo human distal radius.

Calcium isotope ratios in animal and human bone

Science.gov (United States)

Reynard, L. M.; Henderson, G. M.; Hedges, R. E. M.

2010-07-01

Calcium isotopes in tissues are thought to be influenced by an individual's diet, reflecting parameters such as trophic level and dairy consumption, but this has not been carefully assessed. We report the calcium isotope ratios (δ 44/42Ca) of modern and archaeological animal and human bone ( n = 216). Modern sheep raised at the same location show 0.14 ± 0.08‰ higher δ 44/42Ca in females than in males, which we attribute to lactation by the ewes. In the archaeological bone samples the calcium isotope ratios of the herbivorous fauna vary by location. At a single site, the archaeological fauna do not show a trophic level effect. Humans have lower δ 44/42Ca than the mean site fauna by 0.22 ± 0.22‰, and the humans have a greater δ 44/42Ca range than the animals. No effect of sex or age on the calcium isotope ratios was found, and intra-individual skeletal δ 44/42Ca variability is negligible. We rule out dairy consumption as the main cause of the lower human δ 44/42Ca, based on results from sites pre-dating animal domestication and dairy availability, and suggest instead that individual physiology and calcium intake may be important in determining bone calcium isotope ratios.

34 CFR 674.59 - Cancellation for military service.

Science.gov (United States)

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false Cancellation for military service. 674.59 Section 674... Cancellation for military service. (a) Cancellation on a Defense loan. (1) An institution must cancel up to 50... cancellation rate is 121/2 percent of the original loan principal, plus the interest on the unpaid balance...

T3 Regulates a Human Macrophage-Derived TSH-β Splice Variant: Implications for Human Bone Biology.

Science.gov (United States)

Baliram, R; Latif, R; Morshed, S A; Zaidi, M; Davies, T F

2016-09-01

TSH and thyroid hormones (T3 and T4) are intimately involved in bone biology. We have previously reported the presence of a murine TSH-β splice variant (TSH-βv) expressed specifically in bone marrow-derived macrophages and that exerted an osteoprotective effect by inducing osteoblastogenesis. To extend this observation and its relevance to human bone biology, we set out to identify and characterize a TSH-β variant in human macrophages. Real-time PCR analyses using human TSH-β-specific primers identified a 364-bp product in macrophages, bone marrow, and peripheral blood mononuclear cells that was sequence verified and was homologous to a human TSH-βv previously reported. We then examined TSH-βv regulation using the THP-1 human monocyte cell line matured into macrophages. After 4 days, 46.1% of the THP-1 cells expressed the macrophage markers CD-14 and macrophage colony-stimulating factor and exhibited typical morphological characteristics of macrophages. Real-time PCR analyses of these cells treated in a dose-dependent manner with T3 showed a 14-fold induction of human TSH-βv mRNA and variant protein. Furthermore, these human TSH-βv-positive cells, induced by T3 exposure, had categorized into both M1 and M2 macrophage phenotypes as evidenced by the expression of macrophage colony-stimulating factor for M1 and CCL-22 for M2. These data indicate that in hyperthyroidism, bone marrow resident macrophages have the potential to exert enhanced osteoprotective effects by oversecreting human TSH-βv, which may exert its local osteoprotective role via osteoblast and osteoclast TSH receptors.

Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

Science.gov (United States)

Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)

2000-01-01

The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

Glycation Contributes to Interaction Between Human Bone Alkaline Phosphatase and Collagen Type I.

Science.gov (United States)

Halling Linder, Cecilia; Enander, Karin; Magnusson, Per

2016-03-01

Bone is a biological composite material comprised primarily of collagen type I and mineral crystals of calcium and phosphate in the form of hydroxyapatite (HA), which together provide its mechanical properties. Bone alkaline phosphatase (ALP), produced by osteoblasts, plays a pivotal role in the mineralization process. Affinity contacts between collagen, mainly type II, and the crown domain of various ALP isozymes were reported in a few in vitro studies in the 1980s and 1990s, but have not attracted much attention since, although such interactions may have important implications for the bone mineralization process. The objective of this study was to investigate the binding properties of human collagen type I to human bone ALP, including the two bone ALP isoforms B1 and B2. ALP from human liver, human placenta and E. coli were also studied. A surface plasmon resonance-based analysis, supported by electrophoresis and blotting, showed that bone ALP binds stronger to collagen type I in comparison with ALPs expressed in non-mineralizing tissues. Further, the B2 isoform binds significantly stronger to collagen type I in comparison with the B1 isoform. Human bone and liver ALP (with identical amino acid composition) displayed pronounced differences in binding, revealing that post-translational glycosylation properties govern these interactions to a large extent. In conclusion, this study presents the first evidence that glycosylation differences in human ALPs are of crucial importance for protein-protein interactions with collagen type I, although the presence of the ALP crown domain may also be necessary. Different binding affinities among the bone ALP isoforms may influence the mineral-collagen interface, mineralization kinetics, and degree of bone matrix mineralization, which are important factors determining the material properties of bone.

Human bone hardness seems to depend on tissue type but not on anatomical site in the long bones of an old subject.

Science.gov (United States)

Ohman, Caroline; Zwierzak, Iwona; Baleani, Massimiliano; Viceconti, Marco

2013-02-01

It has been hypothesised that among different human subjects, the bone tissue quality varies as a function of the bone segment morphology. The aim of this study was to assess and compare the quality, evaluated in terms of hardness of packages of lamellae, of cortical and trabecular bones, at different anatomical sites within the human skeleton. The contralateral six long bones of an old human subject were indented at different levels along the diaphysis and at both epiphyses of each bone. Hardness value, which is correlated to the degree of mineralisation, of both cortical and trabecular bone tissues was calculated for each indentation location. It was found that the cortical bone tissue was harder (+18%) than the trabecular one. In general, the bone hardness was found to be locally highly heterogeneous. In fact, considering one single slice obtained for a bone segment, the coefficient of variation of the hardness values was up to 12% for cortical bone and up to 17% for trabecular bone. However, the tissue hardness was on average quite homogeneous within and among the long bones of the studied donor, although differences up to 9% among levels and up to 7% among bone segments were found. These findings seem not to support the mentioned hypothesis, at least not for the long bones of an old subject.

Morphological studies at subchondral bone structures in human early arthrosis. Final report; Morphologische Studien an subchondralen Knochenstrukturen bei humanen Frueharthrosen. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

NONE

1992-12-31

Quantitative histomorphometric studies using an image analysis system were performed simultaneously on hyaline cartilage, calcified cartilage and subchondral cancellous bone of human tibial heads for detailed information about the pathogenesis of arthrosis. Joint structures need to be fully detected in three dimensions since measurement values are more affected by topographical aspects than by either age, or sex, or arthrosin stage. Mechanical factors were found to affect essentially the initiation and progression of arthrosis. Results are demonstrated in detail. (orig.) [Deutsch] Um detaillierte Aussagen ueber die Pathogenese der Arthrose machen zu koennen, wurden hyaliner Knorpel, Kalkknorpel und subchondrale Spongiosa menschlicher Tibiakoepfe gleichzeitig mit Hilfe eines Bildanalysesystems quantitativ histomorphometrisch untersucht. Eine umfangreiche dreidimensionale Erfassung der Gelenkstrukturen ist erforderlich, da sich topographische Aspekte wesentlich staerker auf die Messwerte auswirken als Alter, Geschlecht oder Arthrosestadium. Insgesamt zeigt sich ein wesentlicher Einfluss mechanischer Faktoren auf die Arthroseinitiierung und -progredienz. Die Ergebnisse werden detailliert dargestellt. (orig.)

Radiation dosimetry in human bone using electron paramagnetic resonance

International Nuclear Information System (INIS)

Breen, S.L.

1995-01-01

Accurate measurements of dose in bone are required in order to improve the dosimetry of systemic radiotherapy for osseous metastases. Bone is an integrating dosimeter which records the radiation history of the skeleton. During irradiation, electrons become trapped in the crystalline component of bone mineral (hydroxyapatite). The traps are very stable; at room temperature, emptying of the traps occurs with a half-life of many years. The population of trapped unpaired electrons is proportional to the radiation dose administered to the bone and can be measured in excised bone samples using electron paramagnetic resonance (EPR). EPR spectra of synthetic hydroxyapatite, irradiated with Co-60, were obtained at room temperature and at 77 K. At room temperature, the radiation-induced signal, with a g-value of 2.001 ± 0.001 increased linearly with absorbed dose above a lower threshold of 3 Gy, up to doses of 200 Gy. In contrast with pure hydroxyapatite, EPR spectra of excised human bone showed a broad 'native' signal, due to the organic component of bone, which masks the dosimetrically important signal. This native signal is highly variable from sample to sample and precludes the use of EPR as an absolute dosimetry technique. However, after subtraction of the background signal, irradiated human bone showed a linear response with a lower limit of measurement similar to that of synthetic hydroxyapatite. Bone is an in vivo linear dosimeter which can be exploited to develop accurate estimates of the radiation dose delivered during systemic radiotherapy and teletherapy. However, improved sensitivity of the EPR dosimetry technique is necessary before it can be applied reliably in clinical situations. (author)

Age changes in human bone: an overview

Energy Technology Data Exchange (ETDEWEB)

Sharpe, W.D.

1977-12-03

The human skeleton steadily changes structure and mass during life because of a variety of internal and external factors. Extracellular substance and bone cells get old, characteristic structural remodeling occurs with age and these age-related changes are important in the discrimination between pathological and physiological changes. Perhaps 20 percent of the bone mass is lost between the fourth and the ninth decades, osteoblasts function less efficiently and gradual loss of bone substance is enhanced by delayed mineralization of an increased surface area of thin and relatively less active osteoid seams. After the fifth decade, osteoclasia and the number of Howship's lacunae increase, and with age, the number of large osteolytic osteocytes increases as the number of small osteocytes declines and empty osteocyte lacunae become more common. The result is greater liability to fracture and diminished healing or replacement of injured bone.

Low dose PTH improves metaphyseal bone healing more when muscles are paralyzed.

Science.gov (United States)

Sandberg, Olof; Macias, Brandon R; Aspenberg, Per

2014-06-01

Stimulation of bone formation by PTH is related to mechanosensitivity. The response to PTH treatment in intact bone could therefore be blunted by unloading. We studied the effects of mechanical loading on the response to PTH treatment in bone healing. Most fractures occur in the metaphyses, therefor we used a model for metaphyseal bone injury. One hind leg of 20 male SD rats was unloaded via intramuscular botulinum toxin injections. Two weeks later, the proximal unloaded tibia had lost 78% of its trabecular contents. At this time-point, the rats received bilateral proximal tibiae screw implants. Ten of the 20 rats were given daily injections of 5 μg/kg PTH (1-34). After two weeks of healing, screw fixation was measured by pull-out, and microCT of the distal femur cancellous compartment was performed. Pull-out force provided an estimate for cancellous bone formation after trauma. PTH more than doubled the pull-out force in the unloaded limbs (from 14 to 30 N), but increased it by less than half in the loaded ones (from 30 to 44 N). In relative terms, PTH had a stronger effect on pull-out force in unloaded bone than in loaded bone (p=0.03). The results suggest that PTH treatment for stimulation of bone healing does not require simultaneous mechanical stimulation. Copyright © 2014 Elsevier Inc. All rights reserved.

Treatment of midshaft clavicular nonunion with plate fixation and autologous bone grafting

DEFF Research Database (Denmark)

Olsen, Bo Sanderhoff; Vaesel, M T; Søjbjerg, Jens Ole

1995-01-01

We studied the results of 16 consecutive midshaft clavicular nonunions operated on at the Shoulder and Elbow Clinic during the period from 1990 to 1993. All patients were treated with rigid 3.5 mm plate fixation and autologous cancellous bone grafting. Union of the fractures was achieved in all...... except one case, with a reconstruction ratio (restoration of bone length) of 0.96 (range 0.88 to 1.03). At follow-up 12 of 16 patients had returned to their preinjury activity level and according to the Constant score had obtained an excellent result. Two patients were graded as good, one as fair......, and one had a failure. Thirteen of 16 patients were satisfied with the cosmetic outcome, assessing their cosmetic result as either good or excellent. Rigid plate fixation and restoration of clavicular length with autologous cancellous bone graft is recommended for the treatment of symptomatic clavicular...

78 FR 18594 - Notice of Cancelation for Call of the President's Advisory Council on Faith-Based and...

Science.gov (United States)

2013-03-27

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Notice of Cancelation for Call of the President's Advisory Council on Faith-Based and Neighborhood Partnerships Notice of Cancelation: This notice was published in...: March 21, 2013. Ben O'Dell, Associate Director for Center for Faith-based and Neighborhood Partnerships...

Physics of ultrasonic wave propagation in bone and heart characterized using Bayesian parameter estimation

Science.gov (United States)

Anderson, Christian Carl

This Dissertation explores the physics underlying the propagation of ultrasonic waves in bone and in heart tissue through the use of Bayesian probability theory. Quantitative ultrasound is a noninvasive modality used for clinical detection, characterization, and evaluation of bone quality and cardiovascular disease. Approaches that extend the state of knowledge of the physics underpinning the interaction of ultrasound with inherently inhomogeneous and isotropic tissue have the potential to enhance its clinical utility. Simulations of fast and slow compressional wave propagation in cancellous bone were carried out to demonstrate the plausibility of a proposed explanation for the widely reported anomalous negative dispersion in cancellous bone. The results showed that negative dispersion could arise from analysis that proceeded under the assumption that the data consist of only a single ultrasonic wave, when in fact two overlapping and interfering waves are present. The confounding effect of overlapping fast and slow waves was addressed by applying Bayesian parameter estimation to simulated data, to experimental data acquired on bone-mimicking phantoms, and to data acquired in vitro on cancellous bone. The Bayesian approach successfully estimated the properties of the individual fast and slow waves even when they strongly overlapped in the acquired data. The Bayesian parameter estimation technique was further applied to an investigation of the anisotropy of ultrasonic properties in cancellous bone. The degree to which fast and slow waves overlap is partially determined by the angle of insonation of ultrasound relative to the predominant direction of trabecular orientation. In the past, studies of anisotropy have been limited by interference between fast and slow waves over a portion of the range of insonation angles. Bayesian analysis estimated attenuation, velocity, and amplitude parameters over the entire range of insonation angles, allowing a more complete

Patient experiences with interventions to reduce surgery cancellations

DEFF Research Database (Denmark)

Hovlid, Einar; von Plessen, Christian; Haug, Kjell

2013-01-01

The cancellation of planned surgery harms patients, increases waiting times and wastes scarce health resources. Previous studies have evaluated interventions to reduce cancellations from medical and management perspectives; these have focused on cost, length of stay, improved efficiency......, and reduced post-operative complications. In our case a hospital had experienced high cancellation rates and therefore redesigned their pathway for elective surgery to reduce cancelations. We studied how patients experienced interventions to reduce cancellations....

Cannabis sativa smoke inhalation decreases bone filling around titanium implants: a histomorphometric study in rats.

Science.gov (United States)

Nogueira-Filho, Getulio da R; Cadide, Tiago; Rosa, Bruno T; Neiva, Tiago G; Tunes, Roberto; Peruzzo, Daiane; Nociti, Francisco Humberto; César-Neto, João B

2008-12-01

Although the harmful effect of tobacco smoking on titanium implants has been documented, no studies have investigated the effects of cannabis sativa (marijuana) smoking. Thus, this study investigated whether marijuana smoke influences bone healing around titanium implants. Thirty Wistar rats were used. After anesthesia, the tibiae surface was exposed and 1 screw-shaped titanium implant was placed bilaterally. The animals were randomly assigned to one of the following groups: control (n = 15) and marijuana smoke inhalation (MSI) 8 min/d (n = 15). Urine samples were obtained to detect the presence of tetra-hidro-cannabinoid. After 60 days, the animals were killed. The degree of bone-to-implant contact and the bone area within the limits of the threads of the implant were measured in the cortical (zone A) and cancellous bone (zone B). Tetra-hidro-cannabinoid in urine was positive only for the rats of MSI group. Intergroup analysis did not indicate differences in zone A-cortical bone (P > 0.01), however, a negative effect of marijuana smoke (MSI group) was observed in zone B-cancellous bone for bone-to-implant contact and bone area (Student's t test, P smoke on bone healing may represent a new concern for implant success/failure.

Microstructural, densitometric and metabolic variations in bones from rats with normal or altered skeletal states.

Directory of Open Access Journals (Sweden)

Andrew N Luu

Full Text Available High resolution μCT, and combined μPET/CT have emerged as non-invasive techniques to enhance or even replace dual energy X-ray absorptiometry (DXA as the current preferred approach for fragility fracture risk assessment. The aim of this study was to assess the ability of µPET/CT imaging to differentiate changes in rat bone tissue density and microstructure induced by metabolic bone diseases more accurately than current available methods.Thirty three rats were divided into three groups of control, ovariectomy and vitamin-D deficiency. At the conclusion of the study, animals were subjected to glucose ((18FDG and sodium fluoride (Na(18F PET/CT scanning. Then, specimens were subjected to µCT imaging and tensile mechanical testing.Compared to control, those allocated to ovariectomy and vitamin D deficiency groups showed 4% and 22% (significant increase in (18FDG uptake values, respectively. DXA-based bone mineral density was higher in the vitamin D deficiency group when compared to the other groups (cortical bone, yet μCT-based apparent and mineral density results were not different between groups. DXA-based bone mineral density was lower in the ovariectomy group when compared to the other groups (cancellous bone; yet μCT-based mineral density results were not different between groups, and the μCT-based apparent density results were lower in the ovariectomy group compared to the other groups.PET and micro-CT provide an accurate three-dimensional measurement of the changes in bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity. As osteomalacia is characterized by impaired bone mineralization, the use of densitometric analyses may lead to misinterpretation of the condition as osteoporosis. In contrast, µCT alone and in combination with the PET component certainly provides an accurate three-dimensional measurement of the changes in both bone tissue mineral density, as well as

Low elastic modulus titanium–nickel scaffolds for bone implants

International Nuclear Information System (INIS)

Li, Jing; Yang, Hailin; Wang, Huifeng; Ruan, Jianming

2014-01-01

The superelastic nature of repeating the human bones is crucial to the ideal artificial biomedical implants to ensure smooth load transfer and foster the ingrowth of new bone tissues. Three dimensional interconnected porous TiNi scaffolds, which have the tailorable porous structures with micro-hole, were fabricated by slurry immersing with polymer sponge and sintering method. The crystallinity and phase composition of scaffolds were studied by X-ray diffraction. The pore morphology, size and distribution in the scaffolds were characterized by scanning electron microscopy. The porosity ranged from 65 to 72%, pore size was 250–500 μm. Compressive strength and elastic modulus of the scaffolds were ∼ 73 MPa and ∼ 3GPa respectively. The above pore structural and mechanical properties are similar to those of cancellous bone. In the initial cell culture test, osteoblasts adhered well to the scaffold surface during a short time, and then grew smoothly into the interconnected pore channels. These results indicate that the porous TiNi scaffolds fabricated by this method could be bone substitute materials. - Highlights: • A novel approach for the fabrication of porous TiNi scaffolds • Macroporous structures are replicated from the polymer sponge template. • The pore characteristics and mechanical properties of TiNi scaffolds agree well with the requirement of trabecular bone. • Cytocompatibility of TiNi scaffolds is assessed, and it closely associated with pore property

Effects of Implant-Associated Osteomyelitis on Cefuroxime Bone Pharmacokinetics

DEFF Research Database (Denmark)

Tøttrup, Mikkel; Bue, Mats; Koch, Janne

2016-01-01

Background: The prolonged antibiotic therapy that is often needed for successful management of osteomyelitis may be related to incomplete penetration of antibiotics into the target site. The objective of this study was to assess the effects of implant-associated osteomyelitis on cefuroxime...... cavity up to MICs of 2 mg/L compared with the other tissues, but the time was shorter for higher MICs.  Conclusions: Cefuroxime penetration into infected cancellous bone was incomplete but comparable with that in healthy bone. The destructive bone processes associated with acute osteomyelitis reduced...

Correlation between the thickness of the crestal and buccolingual cortical bone at varying depths and implant stability quotients.

Directory of Open Access Journals (Sweden)

Kanthanat Chatvaratthana

Full Text Available Resonance frequency analysis (RFA is clinically used in dentistry to access the stiffness of dental implants in surrounding bone. However, the clear advantages and disadvantages of this method are still inconclusive. The aim of this study was to investigate and compare implant stability quotient (ISQ values obtained from RFA with parameters obtained from a cone beam computed tomography (CBCT scan of the same region.Nineteen implants (Conelog were inserted in the posterior maxillary and mandibular partially edentulous regions of 16 patients. At the time of implant placement, the ISQ values were obtained using RFA (Osstell. CBCT was used to measure the thickness of the crestal, cortical, buccolingual cortical, and cancellous bone at 3, 6, and 9 mm below the crestal bone level, as indicated by radiographic markers. The ratio of the thickness of the cortical to cancellous bone at varying depths was also calculated and classified into 4 groups (Group 1-4.There was a strong correlation between the crestal cortical bone thickness and ISQ values (P<0.001. The thickness of the buccolingual cortical bone and ratio of the cortical to cancellous bone thickness at 3 mm were significantly related to the ISQ (P = 0.018 and P = 0.034, respectively. Furthermore, the ISQs in Group 1 were the highest compared with those in Group 2 and Group 3, whereas the CBCT parameters at 6 and 9 mm did not have any specific correlation with the ISQ values.This study showed that the ISQ values obtained from RFA highly correlated with the quantity and quality of bone 3 mm below the crestal bone level. The correlation between the ISQ and bone surrounding the implant site was dependent on the depth of measurement. Therefore, RFA can help to predict the marginal bone level, as confirmed in this study.

The correlation between mineralization degree and bone tissue stiffness in the porcine mandibular condyle

NARCIS (Netherlands)

Willems, N.M.B.K.; Mulder, L.; Toonder, den J.M.J.; Zentner, A.; Langenbach, G.E.J.

2014-01-01

The aim of this study was to correlate the local tissue mineral density (TMD) with the bone tissue stiffness. It was hypothesized that these variables are positively correlated. Cancellous and cortical bone samples were derived from ten mandibular condyles taken from 5 young and 5 adult female pigs.

The correlation between metacarpal bone mineral content and bone mineral density of the jawbone in implant patients

International Nuclear Information System (INIS)

Kuroda, Toshinobu; Takamori, Hitoshi; Yosue, Takashi

2006-01-01

This study estimated the relationship between metacarpal bone mineral content and jawbone density. The subjects were 141 patients who desired implant treatment and had undergone a thorough pre-operative CT examination. In the maxilla, bone mineral density (BMD) was measured at the cancellous bone between the nasal cavity and the maxillary sinus. In the mandible, BMD was measured at the cancellous bone beneath the mental foramen. The CT numbers were corrected by the quantitative computer tomography (QCT) method. Furthermore, the cortical indices of the mandible, i.e. C-PMI (Central-Panoramic Mandibular Index), and MCW (Mandibular Cortical Width) were measured and calculated from panoramic radiographs. The bone mineral content of the total body was obtained by ΣGS/D and MCI through Microdensitometry. The following results were obtained. Between the maxillary BMD and ΣGS/D and between the mandibular BMD and ΣGS/D, there was a correlation in females but no correlation in males. Between the maxillary BMD and MCI, there was a correlation in females but no correlation in males. However, in the mandibular BMD and MCI there was no correlation in females and males. Between C-PMI and ΣGS/D there was a correlation in both females and males. Between C-PMI and MCI there was a correlation in both females and males. Between MCW and ΣGS/D there was a correlation in both females and males. Between MCW and MCI there was a correlation in females, but no correlation in males. From the above results, it was concluded that the maxillary BMD and the cortical index of the mandible reflected changes in the metacarpal bone mineral content, while mandibular BMD did not. (author)

Sorption behavior of human bone powder towards 60 Co and 65 Zn

International Nuclear Information System (INIS)

Abdel-Fattah, A.T.; Essa, M.W.A.; Mohamed, S.A.; Molokhia, M.K.

1990-01-01

Human bone powder 30-40 Μ in diameter was prepared from human bone femurs as fat-free (FFB), protein-free (PFB) or left untreated as raw bone powder (RB). The sorption behavior of human bone powder towards 60 Co and 65 Zn was studied. The uptake changed with the type of bone powder to be : PFB>FFB>RB. The increase in the concentration of cobalt(from 10 -6 to 10 -1 Mole/litre)and of zinc (from 10 -7 to 10 -4 M/1) increased the uptake of 60 Co and 65 Zn. Freunclich-type isotherm was successfully applied on the uptake data of both ions and the slopes of these isotherms were, nearly, directly proportional to their uptake values. The uptake was found to be less influenced by the PH. In case of cobalt the uptake increased till PH 4, followed by a plateau till PH 8 while in case of zinc the PH effect is much less pronounced

[Significance of bone mineral density and modern cementing technique for in vitro cement penetration in total shoulder arthroplasty].

Science.gov (United States)

Pape, G; Raiss, P; Kleinschmidt, K; Schuld, C; Mohr, G; Loew, M; Rickert, M

2010-12-01

scans were applied to analyse the cement penetration into the cancellous bone. The mean temperature during the in-vivo arthroplasty of the glenoid was 29.4 °C (27.2-31 °C) before and 26.2 °C (25-27.5 °C) after jet-lavage. The overall peak BMD was 0.59 (range 0.33-0.99) g/cm (2). Mean cement penetration was 107.9 (range 67.6-142.3) mm (2) in the peg group and 128.3 (range 102.6-170.8) mm (2) in the keel group. The thickness of the cement layer varied from 0 to 2.1 mm in the pegged group and from 0 to 2.4 mm in the keeled group. A strong negative correlation between BMD and mean cement penetration was found for the peg group (r (2) = -0.834; p cement into the cancellous bone. Data from the in-vivo temperature measurement indicate that the temperature at the glenohumeral surface under operation differs from the body core temperature and should be considered in further in-vitro studies with human specimens. Bone mineral density is negatively correlated to cement penetration in the glenoid. The application of a modern cementing technique in the glenoid provides sufficient cementing penetration although there is an inhomogenous dispersion of the cement. The findings of this study should be considered in further discussions about cementing technique and cement penetration into the cancellous bone of the glenoid. © Georg Thieme Verlag KG Stuttgart · New York.

Creep of trabecular bone from the human proximal tibia

Energy Technology Data Exchange (ETDEWEB)

Novitskaya, Ekaterina, E-mail: eevdokim@ucsd.edu [Mechanical and Aerospace Engineering, UC, San Diego, La Jolla, CA 92093 (United States); Materials Science and Engineering Program, UC, San Diego, La Jolla, CA 92093 (United States); Zin, Carolyn [Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218 (United States); Chang, Neil; Cory, Esther; Chen, Peter [Departments of Bioengineering and Orthopaedic Surgery, UC, San Diego, La Jolla, CA 92093 (United States); D’Lima, Darryl [Shiley Center for Orthopaedic Research and Education, Scripps Health, La Jolla, CA 92037 (United States); Sah, Robert L. [Materials Science and Engineering Program, UC, San Diego, La Jolla, CA 92093 (United States); Departments of Bioengineering and Orthopaedic Surgery, UC, San Diego, La Jolla, CA 92093 (United States); McKittrick, Joanna [Mechanical and Aerospace Engineering, UC, San Diego, La Jolla, CA 92093 (United States); Materials Science and Engineering Program, UC, San Diego, La Jolla, CA 92093 (United States)

2014-07-01

Creep is the deformation that occurs under a prolonged, sustained load and can lead to permanent damage in bone. Creep in bone is a complex phenomenon and varies with type of loading and local mechanical properties. Human trabecular bone samples from proximal tibia were harvested from a 71-year old female cadaver with osteoporosis. The samples were initially subjected to one cycle load up to 1% strain to determine the creep load. Samples were then loaded in compression under a constant stress for 2 h and immediately unloaded. All tests were conducted with the specimens soaked in phosphate buffered saline with proteinase inhibitors at 37 °C. Steady state creep rate and final creep strain were estimated from mechanical testing and compared with published data. The steady state creep rate correlated well with values obtained from bovine tibial and human vertebral trabecular bone, and was higher for lower density samples. Tissue architecture was analyzed by micro-computed tomography (μCT) both before and after creep testing to assess creep deformation and damage accumulated. Quantitative morphometric analysis indicated that creep induced changes in trabecular separation and the structural model index. A main mode of deformation was bending of trabeculae. - Highlights: • Compressive creep tests of human trabecular bone across the tibia were performed. • The creep rate was found to be inversely proportional to the density of the samples. • μ-computed tomography before and after testing identified regions of deformation. • Bending of the trabeculae was found to be the main deformation mode.

Characterization of Human Bone Alkaline Phosphatase in Pichia Pastoris

Science.gov (United States)

Malone, Christine C.; Ciszak, Eva; Karr, Laurel J.

1999-01-01

A soluble form of human bone alkaline phosphatase has been expressed in a recombinant strain of the methylotrophic yeast Pichia pastoris. We constructed a plasmid containing cDNA encoding for human bone alkaline phosphatase, with the hydrophobic carboxyl terminal portion deleted. Alkaline phosphatase was secreted into the medium to a level of 32mg/L when cultured in shake flasks, and enzyme activity was 12U/mg, as measured by a spectrophotometric assay. By conversion to a fermentation system, a yield of 880mg/L has been achieved with an enzyme activity of 968U/mg. By gel electrophoresis analysis, it appears that greater than 50% of the total protein in the fermentation media is alkaline phosphatase. Although purification procedures are not yet completely optimized, they are expected to include filtration, ion exchange and affinity chromatography. Our presentation will focus on the purification and crystallization results up to the time of the conference. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

Bone Canopies in Pediatric Renal Osteodystrophy

DEFF Research Database (Denmark)

Pereira, Renata C; Levin Andersen, Thomas; Friedman, Peter A

2016-01-01

Pediatric renal osteodystrophy (ROD) is characterized by changes in bone turnover, mineralization, and volume that are brought about by alterations in bone resorption and formation. The resorptive and formative surfaces on the cancellous bone are separated from the marrow cavity by canopies...... and their association with biochemical and bone histomorphometric parameters in 106 pediatric chronic kidney disease (CKD) patients (stage 2-5) across the spectrum of ROD. Canopies in CKD patients often appeared as thickened multilayered canopies, similar to previous reports in patients with primary hyperparathyroidism....... This finding contrasts with the thin appearance reported in healthy individuals with normal kidney function. Furthermore, canopies in pediatric CKD patients showed immunoreactivity to the PTH receptor (PTHR1) as well as to the receptor activator of nuclear factor kappa-B ligand (RANKL). The number of surfaces...

Group study of an "undercover" test for visuospatial neglect: invisible cancellation can reveal more neglect than standard cancellation.

Science.gov (United States)

Wojciulik, E; Rorden, C; Clarke, K; Husain, M; Driver, J

2004-09-01

Visual neglect is a relatively common deficit after brain damage, particularly strokes. Cancellation tests provide standard clinical measures of neglect severity and deficits in daily life. A recent single-case study introduced a new variation on standard cancellation. Instead of making a visible mark on each target found, the patient made invisible marks (recorded with carbon paper underneath, for later scoring). Such invisible cancellation was found to reveal more neglect than cancellation with visible marks. Here we test the generality of this. Twenty three successive cases with suspected neglect each performed cancellation with visible or invisible marks. Neglect of contralesional targets was more pronounced with invisible marks. Indeed, about half of the patients only showed neglect in this version. For cases showing more neglect with invisible marks, stronger neglect of contralesional targets correlated with more revisits to ipsilesional targets for making additional invisible marks upon them. These results indicate that cancellation with invisible marks can reveal more neglect than standard cancellation with visible marks, while still providing a practical bedside test. Our observations may be consistent with recent proposals that demands on spatial working memory (required to keep track of previously found items only when marked invisibly) can exacerbate spatial neglect.

77 FR 50702 - Cardiovascular and Renal Drugs Advisory Committee; Cancellation

Science.gov (United States)

2012-08-22

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2012-N-0001] Cardiovascular and Renal Drugs Advisory Committee; Cancellation AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The meeting of the Cardiovascular and Renal Drugs Advisory Committee scheduled for...

The identification of proteoglycans and glycosaminoglycans in archaeological human bones and teeth.

Science.gov (United States)

Coulson-Thomas, Yvette M; Coulson-Thomas, Vivien J; Norton, Andrew L; Gesteira, Tarsis F; Cavalheiro, Renan P; Meneghetti, Maria Cecília Z; Martins, João R; Dixon, Ronald A; Nader, Helena B

2015-01-01

Bone tissue is mineralized dense connective tissue consisting mainly of a mineral component (hydroxyapatite) and an organic matrix comprised of collagens, non-collagenous proteins and proteoglycans (PGs). Extracellular matrix proteins and PGs bind tightly to hydroxyapatite which would protect these molecules from the destructive effects of temperature and chemical agents after death. DNA and proteins have been successfully extracted from archaeological skeletons from which valuable information has been obtained; however, to date neither PGs nor glycosaminoglycan (GAG) chains have been studied in archaeological skeletons. PGs and GAGs play a major role in bone morphogenesis, homeostasis and degenerative bone disease. The ability to isolate and characterize PG and GAG content from archaeological skeletons would unveil valuable paleontological information. We therefore optimized methods for the extraction of both PGs and GAGs from archaeological human skeletons. PGs and GAGs were successfully extracted from both archaeological human bones and teeth, and characterized by their electrophoretic mobility in agarose gel, degradation by specific enzymes and HPLC. The GAG populations isolated were chondroitin sulfate (CS) and hyaluronic acid (HA). In addition, a CSPG was detected. The localization of CS, HA, three small leucine rich PGs (biglycan, decorin and fibromodulin) and glypican was analyzed in archaeological human bone slices. Staining patterns were different for juvenile and adult bones, whilst adolescent bones had a similar staining pattern to adult bones. The finding that significant quantities of PGs and GAGs persist in archaeological bones and teeth opens novel venues for the field of Paleontology.

Spatial distribution of the trace elements zinc, strontium and lead in human bone tissue☆

Science.gov (United States)

Pemmer, B.; Roschger, A.; Wastl, A.; Hofstaetter, J.G.; Wobrauschek, P.; Simon, R.; Thaler, H.W.; Roschger, P.; Klaushofer, K.; Streli, C.

2013-01-01

Trace elements are chemical elements in minute quantities, which are known to accumulate in the bone. Cortical and trabecular bones consist of bone structural units (BSUs) such as osteons and bone packets of different mineral content and are separated by cement lines. Previous studies investigating trace elements in bone lacked resolution and therefore very little is known about the local concentration of zinc (Zn), strontium (Sr) and lead (Pb) in BSUs of human bone. We used synchrotron radiation induced micro X-ray fluorescence analysis (SR μ-XRF) in combination with quantitative backscattered electron imaging (qBEI) to determine the distribution and accumulation of Zn, Sr, and Pb in human bone tissue. Fourteen human bone samples (10 femoral necks and 4 femoral heads) from individuals with osteoporotic femoral neck fractures as well as from healthy individuals were analyzed. Fluorescence intensity maps were matched with BE images and correlated with calcium (Ca) content. We found that Zn and Pb had significantly increased levels in the cement lines of all samples compared to the surrounding mineralized bone matrix. Pb and Sr levels were found to be correlated with the degree of mineralization. Interestingly, Zn intensities had no correlation with Ca levels. We have shown for the first time that there is a differential accumulation of the trace elements Zn, Pb and Sr in BSUs of human bone indicating different mechanisms of accumulation. PMID:23932972

Electrical impedance spectroscopy as a potential tool for recovering bone porosity

International Nuclear Information System (INIS)

Bonifasi-Lista, C; Cherkaev, E

2009-01-01

This paper deals with the recovery of porosity of bone from measurements of its effective electrical properties. The microstructural information is contained in the spectral measure in the Stieltjes representation of the bone effective complex permittivity or complex conductivity and can be recovered from the measurements over a range of frequencies. The problem of reconstruction of the spectral measure is very ill-posed and requires the use of regularization techniques. We apply the method to the effective electrical properties of cancellous bone numerically calculated using micro-CT images of human vertebrae. The presented method is based on an analytical approach and does not rely on correlation analysis nor on any a priori model of the bone micro-architecture. However the method requires a priori knowledge of the properties of the bone constituents (trabecular tissue and bone marrow). These properties vary from patient to patient. To address this issue, a sensitivity analysis of the technique was performed. Normally distributed random noise was added to the data to simulate uncertainty in the properties of the constituents and possible experimental errors in measurements of the effective properties. The values of porosity calculated from effective complex conductivity are in good agreement with the true values of bone porosity even assuming high level errors in the estimation of the bone components. These results prove the future potential of electrical impedance spectroscopy for in vivo monitoring of level and treatment of osteoporosis.

Determination of Sr90 activity in human bones

International Nuclear Information System (INIS)

Mendonca, Anamelia Habib

1970-01-01

Several studies have been published in the literature on the extent and levels of radioactive contamination of food chains caused by fallout from nuclear weapon tests. According to UNSCEAR, these studies cover a great number of:-areas of the developed world, though large, areas of Asia, Africa and South-America are left aside with only, unsatisfactory information about the levels, of radioactive contamination. In 1968, UNSCEAR recommended that a survey on the contamination of biological materials such as human - bone by fission products and particularly Sr 90 should be encouraged on those areas where only fragmentary information was available. UNSCEAR recommendations call upon the fact that many individuals on such areas of the world have been exposed to Sr 90 contamination from birth to their adult area. Therefore, that group have an Sr 90 skeletal burden very much different from people exposed only at adult age. Based on these considerations, UNSCEAR recommendations called for Sr 90 analysis on human bones from different age groups. In Brazil, studies on the of Sr 90 in human bone are practically non-existent, except for the year of 1959. Following UNSCEAR recommendations, we decided to perform such a survey on Sr 90 levels in human bones. Samples were collected from individuals that died in Rio de Janeiro from accidents. These samples were firstly classified according to social level in very poor and poor groups. Samples were then classified in three age groups ranging 0-18, 18-30 and 30-40 years of age. Results show that levels found in the Brazilian age groups are close to the ones observed in Chile (1969), Argentina and Australia (1966-1968) and slightly, higher than -those observed in Venezuela, Senegal and Jamaica (1969). If one compares the results obtained for the North and South hemispheres respectively, one sees that there was a more pronounced decrease in the levels of Sr 90 content of the of some regions of South America. Our results show no

Enhancement of bone formation in rabbits by recombinant human growth hormone

International Nuclear Information System (INIS)

Ehrnberg, A.; Brosjoe, O.; Laaftman, P.; Nilsson, O.; Stroemberg, L.

1993-01-01

We studied the effect of human recombinant growth hormone on diaphyseal bone in 40 adult rabbits. The diaphyseal periosteum of one femur in each animal was mechanically stimulated by a nylon cerclage band. The bands induced an increase in bone formation, bone mineral content, and maximum torque capacity of the diaphyseal bone at 1 and 2 months. Growth hormone enhanced the anabolic effect of the cerclage bands on bone metabolism, evidenced by a further increase in torsional strength of the femurs. (au) (32 refs.)

Inhibition of radio cobalt uptake by human bone powder using Mg and Ni

International Nuclear Information System (INIS)

Abdel Fattah, A.T.A.; Mohamed, S.A.

1992-01-01

Human bone powder samples of 30 - 40 Μ in diameter were prepared from human bone femurs as fat free (FFB), protein free (PEB) or left untreated as a raw bone powder (RB). The uptake of 60 Co by these types of bone powder took the sequence : PFB > FFB> RB. Stable ions of magnesium and nickel exhibit an inhibition or competing effect on the uptake process of 60 Co. The competing effect did not disturb the uptake sequence. The competing effect of nickel was higher than magnesium

Theory of the cancellation of 4-photon resonances by an off-resonance 3-photon cancellation

DEFF Research Database (Denmark)

Elk, M.; Lambropoulos, P.; Tang, X.

1992-01-01

We present a complete account of our recent work [Phys. Rev. A 44, 31 (1991)] in which we investigate the theory of cancellation by interference between the absorption of three fundamental laser photons and one third-harmonic photon. The theory is formulated in terms of the density matrix so...... as to take detunings, dephasing, and laser bandwidth into account. The result is a theory of cancellation for finite detuning that explains how four-photon resonances can be canceled by a three-photon mechanism if there is an atomic level at near-three-photon resonance. The treatment is extended to focused...

Spatial distribution of the trace elements zinc, strontium and lead in human bone tissue.

Science.gov (United States)

Pemmer, B; Roschger, A; Wastl, A; Hofstaetter, J G; Wobrauschek, P; Simon, R; Thaler, H W; Roschger, P; Klaushofer, K; Streli, C

2013-11-01

Trace elements are chemical elements in minute quantities, which are known to accumulate in the bone. Cortical and trabecular bones consist of bone structural units (BSUs) such as osteons and bone packets of different mineral content and are separated by cement lines. Previous studies investigating trace elements in bone lacked resolution and therefore very little is known about the local concentration of zinc (Zn), strontium (Sr) and lead (Pb) in BSUs of human bone. We used synchrotron radiation induced micro X-ray fluorescence analysis (SR μ-XRF) in combination with quantitative backscattered electron imaging (qBEI) to determine the distribution and accumulation of Zn, Sr, and Pb in human bone tissue. Fourteen human bone samples (10 femoral necks and 4 femoral heads) from individuals with osteoporotic femoral neck fractures as well as from healthy individuals were analyzed. Fluorescence intensity maps were matched with BE images and correlated with calcium (Ca) content. We found that Zn and Pb had significantly increased levels in the cement lines of all samples compared to the surrounding mineralized bone matrix. Pb and Sr levels were found to be correlated with the degree of mineralization. Interestingly, Zn intensities had no correlation with Ca levels. We have shown for the first time that there is a differential accumulation of the trace elements Zn, Pb and Sr in BSUs of human bone indicating different mechanisms of accumulation. © 2013. Published by Elsevier Inc. All rights reserved.

Distribution of radium and plutonium in human bone

International Nuclear Information System (INIS)

Schlenker, R.A.

1985-01-01

This review covers studies of the microdistribution of radium and plutonium in human bone, conducted at Argonne with emphasis on the alpha-spectrometric method of measurement. Alpha spectrometry offers high spatial resolution and is well suited to the measurement of radionuclide concentrations near bone surfaces. With these techniques surface deposit thicknesses have been measured to be about 1 μm thick for isotopes of lead, radium and the actinides, and volume deposits of 226 Ra have been found to be quite nonuniform near bone surfaces, leading to endosteal tissue dose rates that are higher than expected under the assumption of uniform volume concentration normally used in radiation protection calculations. With autoradiography, the bony septa of the mastoid air cell system have been found to be depleted in radium relative to the bone tissue surrounding them; this is expected to have a significant influence on the dosimetry of the mastoid epithelia. A combination of autoradiographic and morphometric measurements indicates that specific activities in the axial skeleton are higher than in the appendicular skeleton, primarily because the former has higher bone surface-to-volume ratios and higher bone surface concentrations of plutonium. 19 references, 14 figures, 6 tables

The identification of proteoglycans and glycosaminoglycans in archaeological human bones and teeth.

Directory of Open Access Journals (Sweden)

Yvette M Coulson-Thomas

Full Text Available Bone tissue is mineralized dense connective tissue consisting mainly of a mineral component (hydroxyapatite and an organic matrix comprised of collagens, non-collagenous proteins and proteoglycans (PGs. Extracellular matrix proteins and PGs bind tightly to hydroxyapatite which would protect these molecules from the destructive effects of temperature and chemical agents after death. DNA and proteins have been successfully extracted from archaeological skeletons from which valuable information has been obtained; however, to date neither PGs nor glycosaminoglycan (GAG chains have been studied in archaeological skeletons. PGs and GAGs play a major role in bone morphogenesis, homeostasis and degenerative bone disease. The ability to isolate and characterize PG and GAG content from archaeological skeletons would unveil valuable paleontological information. We therefore optimized methods for the extraction of both PGs and GAGs from archaeological human skeletons. PGs and GAGs were successfully extracted from both archaeological human bones and teeth, and characterized by their electrophoretic mobility in agarose gel, degradation by specific enzymes and HPLC. The GAG populations isolated were chondroitin sulfate (CS and hyaluronic acid (HA. In addition, a CSPG was detected. The localization of CS, HA, three small leucine rich PGs (biglycan, decorin and fibromodulin and glypican was analyzed in archaeological human bone slices. Staining patterns were different for juvenile and adult bones, whilst adolescent bones had a similar staining pattern to adult bones. The finding that significant quantities of PGs and GAGs persist in archaeological bones and teeth opens novel venues for the field of Paleontology.

Aging and Fracture of Human Cortical Bone and Tooth Dentin

Energy Technology Data Exchange (ETDEWEB)

Ager, Joel; Koester, Kurt J.; Ager III, Joel W.; Ritchie, Robert O.

2008-05-07

Mineralized tissues, such as bone and tooth dentin, serve as structural materials in the human body and, as such, have evolved to resist fracture. In assessing their quantitative fracture resistance or toughness, it is important to distinguish between intrinsic toughening mechanisms which function ahead of the crack tip, such as plasticity in metals, and extrinsic mechanisms which function primarily behind the tip, such as crack bridging in ceramics. Bone and dentin derive their resistance to fracture principally from extrinsic toughening mechanisms which have their origins in the hierarchical microstructure of these mineralized tissues. Experimentally, quantification of these toughening mechanisms requires a crack-growth resistance approach, which can be achieved by measuring the crack-driving force, e.g., the stress intensity, as a function of crack extension ("R-curve approach"). Here this methodology is used to study of the effect of aging on the fracture properties of human cortical bone and human dentin in order to discern the microstructural origins of toughness in these materials.

Wavelet-LMS algorithm-based echo cancellers

Science.gov (United States)

Seetharaman, Lalith K.; Rao, Sathyanarayana S.

2002-12-01

This paper presents Echo Cancellers based on the Wavelet-LMS Algorithm. The performance of the Least Mean Square Algorithm in Wavelet transform domain is observed and its application in Echo cancellation is analyzed. The Widrow-Hoff Least Mean Square Algorithm is most widely used algorithm for Adaptive filters that function as Echo Cancellers. The present day communication signals are widely non-stationary in nature and some errors crop up when Least Mean Square Algorithm is used for the Echo Cancellers handling such signals. The analysis of non-stationary signals often involves a compromise between how well transitions or discontinuities can be located. The multi-scale or multi-resolution of signal analysis, which is the essence of wavelet transform, makes Wavelets popular in non-stationary signal analysis. In this paper, we present a Wavelet-LMS algorithm wherein the wavelet coefficients of a signal are modified adaptively using the Least Mean Square Algorithm and then reconstructed to give an Echo-free signal. The Echo Canceller based on this Algorithm is found to have a better convergence and a comparatively lesser MSE (Mean Square error).

Multistage bone-charged distraction osteogenesis for aesthetic reconstruction of an extensive bone deficiency in the mandible.

Science.gov (United States)

Watanabe, Yorikatsu; Sasaki, Ryo; Ando, Tomohiro; Okano, Teruo; Akizuki, Tanetaka

2012-01-01

Alveolar and mandibular bone defects impair occlusion and affect the aesthetics of facial contouring, making it difficult to obtain a satisfactory outcome. Treatment with distraction osteogenesis (DO) is particularly difficult in cases in which the defective region extends to close to the inferior margin of the mandible. To overcome the limits of current DO, we developed a method as follows. In the first stage, a submucosal space necessary for bone grafting was prepared by soft tissue expansion through DO. In the second stage, an iliac corticocancellous bone was transplanted with its cancellous side in close contact with the new bone in the space formed on the labial side into this new space. In the third stage, the grafted bone was distracted. This technique requires time, but each surgery is of minimum invasiveness and does not leave a visible scar; use of this technique may expand the limited indication of current DO and dental implants.

Unicameral bone cyst of the lunate in an adult: case report.

Science.gov (United States)

Gündeş, Hakan; Sahin, Mustafa; Alici, Tugrul

2010-10-30

We report a case of a symptomatic unicameral (simple) bone cyst of the lunate in a 42-year- old woman. The lesion was treated with curettage and cancellous autogenous iliac bone grafting. At five years of follow-up the wrist was pain free, there were no limitations of motion, and the radiographs showed complete obliteration of the cavity. To the best of our knowledge, no other unicameral bone cyst of the lunate has been reported in an adult. Cysts with significant cavities at the carpal bones in an adult should be approached cautiously, as they may require early curettage and bone grafting for healing, before collapse and degenerative changes occur.

Pharmacokinetics of linezolid in bone tissue investigated by in vivo microdialysis

DEFF Research Database (Denmark)

Stolle, L.B.; Plock, N.; Joukhadar, C.

2008-01-01

Pharmacokinetics of unbound anti-infectives in bone is difficult to characterize. The aim of this study was to assess the feasibility of the microdialysis technique to cancellous bone for single dose pharmacokinetic investigations of the anti-infective linezolid. Serial bone biopsies (left tibia......) and microdialysate samples (right tibia: 2 catheters) as well as plasma and bone marrow samples were obtained from 10 pigs. The concentrations of linezolid reached bacteriostatic levels in plasma, bone marrow, bone biopsies and microdialysates. With the use of microdialysis we here present the first results...... for unbound linezolid bone penetration. Unbound linezolid concentrations in bone obtained by microdialysis were lower than might have been expected from previous bone biopsy studies. To achieve effective concentrations (24 h) for susceptible organisms the chosen dose of linezolid might not be sufficient...

Noise canceling in-situ detection

Science.gov (United States)

Walsh, David O.

2014-08-26

Technologies applicable to noise canceling in-situ NMR detection and imaging are disclosed. An example noise canceling in-situ NMR detection apparatus may comprise one or more of a static magnetic field generator, an alternating magnetic field generator, an in-situ NMR detection device, an auxiliary noise detection device, and a computer.

Direct transplantation of native pericytes from adipose tissue: A new perspective to stimulate healing in critical size bone defects.

Science.gov (United States)

König, Matthias A; Canepa, Daisy D; Cadosch, Dieter; Casanova, Elisa; Heinzelmann, Michael; Rittirsch, Daniel; Plecko, Michael; Hemmi, Sonja; Simmen, Hans-Peter; Cinelli, Paolo; Wanner, Guido A

2016-01-01

Fractures with a critical size bone defect (e.g., open fracture with segmental bone loss) are associated with high rates of delayed union and non-union. The prevention and treatment of these complications remain a serious issue in trauma and orthopaedic surgery. Autologous cancellous bone grafting is a well-established and widely used technique. However, it has drawbacks related to availability, increased morbidity and insufficient efficacy. Mesenchymal stromal cells can potentially be used to improve fracture healing. In particular, human fat tissue has been identified as a good source of multilineage adipose-derived stem cells, which can be differentiated into osteoblasts. The main issue is that mesenchymal stromal cells are a heterogeneous population of progenitors and lineage-committed cells harboring a broad range of regenerative properties. This heterogeneity is also mirrored in the differentiation potential of these cells. In the present study, we sought to test the possibility to enrich defined subpopulations of stem/progenitor cells for direct therapeutic application without requiring an in vitro expansion. We enriched a CD146+NG2+CD45- population of pericytes from freshly isolated stromal vascular fraction from mouse fat tissue and tested their osteogenic differentiation capacity in vitro and in vivo in a mouse model for critical size bone injury. Our results confirm the ability of enriched CD146+NG2+CD45- cells to efficiently generate osteoblasts in vitro, to colonize cancellous bone scaffolds and to successfully contribute to regeneration of large bone defects in vivo. This study represents proof of principle for the direct use of enriched populations of cells with stem/progenitor identity for therapeutic applications. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Effect of water on piezoelectricity in bone and collagen.

Science.gov (United States)

Netto, T G; Zimmerman, R L

1975-01-01

Interferometric measurements of bovine bone and tendon show that the values of the piezoelectric strain constant d14 decrease with hydration from the dry values of 0.2 X 10(-14) and 2.0 X 10(-14) m/V, respectively. The decrease of piezoelectricity in tendon is exponential with a characteristic hydration of 7% by weight from which an upper limit of the average molecular weight of the responsible electric dipole moments is deduced. The piezoelectricity in bone decreases relatively slowly with hydration indicating that the electric dipoles in bone collagen are subject to a different cancelling mechanism. PMID:1148359

The role of fat in the prediction of bone strength of porcine lumbar vertebrae by quanititative computed tomography

International Nuclear Information System (INIS)

Chang, G.L.; Tsai, K.H.; Yu, C.Y.; Lin, R.M.

1996-01-01

In order to prevent cancellous bone fractures, and understanding of the strength characteristics of cancellous bone must be achieved. Although there is a definite relationship between the strengt and relative ash content of the vertebrae, the well-known relationship is not practical in clinical use. As we know, QCT was regarded as an ideal method because it is a cross-sectional tecnique. However, no matter what kind of CT machine was used, the physiological factor must be influencing the accuracy in QCT measurement. Because a given region of the vertebrae contains bone mineral, bone matrix, fatty marrow and red marrow. In words, the role of fat content in bony strength and QCT measurement remained obscure. If QCT can reflect the bone strength to a reliable level and the influence of fat on QCT can be clarified, then QCT may become more useful. Therefore, the purpose of this study was to investigate the relationships among fat content, bone strength and QCT. Six freshly female porcine lumbar spinal semgemts were used in this study. Poster 182. (author)

A histomorphometric and micro-computed tomography study of bone regeneration in the maxillary sinus comparing biphasic calcium phosphate and deproteinized cancellous bovine bone in a human split-mouth model

NARCIS (Netherlands)

de Lange, G.L.; Overman, J.R.; Farre-Guasch, E.; Korstjens, C.M.; Hartman, B.; Langenbach, G.E.J.; van Duin, M.A.; Klein-Nulend, J.

2014-01-01

Objective The gain of mineralized bone was compared between deproteinized bovine bone allograft (DBA) and biphasic calcium phosphate (BCP) for dental implant placement. Study Design Five patients with atrophic maxillae underwent bilateral sinus elevation with DBA (Bio-Oss) and BCP (Straumann

An animal model in sheep for biocompatibility testing of biomaterials in cancellous bones.

Science.gov (United States)

Nuss, Katja M R; Auer, Joerg A; Boos, Alois; von Rechenberg, Brigitte

2006-08-15

The past years have seen the development of many synthetic bone replacements. To test their biocompatibility and ability for osseointegration, osseoinduction and -conduction requires their placement within bone preferably in an animal experiment of a higher species. A suitable experimental animal model in sheep with drill holes of 8 mm diameter and 13 mm depth within the proximal and distal humerus and femur for testing biocompatibility issues is introduced. This present sheep model allows the placing of up to 8 different test materials within one animal and because of the standardization of the bone defect, routine evaluation by means of histomorphometry is easily conducted. This method was used successfully in 66 White Alpine Sheep. When the drill holes were correctly placed no complications such as spontaneous fractures were encountered. This experimental animal model serves an excellent basis for testing the biocompatibility of novel biomaterials to be used as bone replacement or new bone formation enhancing materials.

An animal model in sheep for biocompatibility testing of biomaterials in cancellous bones

Directory of Open Access Journals (Sweden)

Boos Alois

2006-08-01

Full Text Available Abstract Background The past years have seen the development of many synthetic bone replacements. To test their biocompatibility and ability for osseointegration, osseoinduction and -conduction requires their placement within bone preferably in an animal experiment of a higher species. Methods A suitable experimental animal model in sheep with drill holes of 8 mm diameter and 13 mm depth within the proximal and distal humerus and femur for testing biocompatibility issues is introduced. Results This present sheep model allows the placing of up to 8 different test materials within one animal and because of the standardization of the bone defect, routine evaluation by means of histomorphometry is easily conducted. This method was used successfully in 66 White Alpine Sheep. When the drill holes were correctly placed no complications such as spontaneous fractures were encountered. Conclusion This experimental animal model serves an excellent basis for testing the biocompatibility of novel biomaterials to be used as bone replacement or new bone formation enhancing materials.

An animal model in sheep for biocompatibility testing of biomaterials in cancellous bones

Science.gov (United States)

Nuss, Katja MR; Auer, Joerg A; Boos, Alois; Rechenberg, Brigitte von

2006-01-01

Background The past years have seen the development of many synthetic bone replacements. To test their biocompatibility and ability for osseointegration, osseoinduction and -conduction requires their placement within bone preferably in an animal experiment of a higher species. Methods A suitable experimental animal model in sheep with drill holes of 8 mm diameter and 13 mm depth within the proximal and distal humerus and femur for testing biocompatibility issues is introduced. Results This present sheep model allows the placing of up to 8 different test materials within one animal and because of the standardization of the bone defect, routine evaluation by means of histomorphometry is easily conducted. This method was used successfully in 66 White Alpine Sheep. When the drill holes were correctly placed no complications such as spontaneous fractures were encountered. Conclusion This experimental animal model serves an excellent basis for testing the biocompatibility of novel biomaterials to be used as bone replacement or new bone formation enhancing materials. PMID:16911787

Nuclear plant cancellations: causes, costs, and consequences

International Nuclear Information System (INIS)

1983-04-01

This study was commissioned in order to help quantify the effects of nuclear plant cancellations on the Nation's electricity prices. This report presents a historical overview of nuclear plant cancellations through 1982, the costs associated with those cancellations, and the reasons that the projects were terminated. A survey is presented of the precedents for regulatory treatment of the costs, the specific methods of cost recovery that were adopted, and the impacts of these decisions upon ratepayers, utility stockholders, and taxpayers. Finally, the report identifies a series of other nuclear plants that remain at risk of canellation in the future, principally as a result of similar demand, finance, or regulatory problems cited as causes of cancellation in the past. The costs associated with these potential cancellations are estimated, along with their regional distributions, and likely methods of cost recovery are suggested

Immune Humanization of Immunodeficient Mice Using Diagnostic Bone Marrow Aspirates from Carcinoma Patients

Science.gov (United States)

Werner-Klein, Melanie; Proske, Judith; Werno, Christian; Schneider, Katharina; Hofmann, Hans-Stefan; Rack, Brigitte; Buchholz, Stefan; Ganzer, Roman; Blana, Andreas; Seelbach-Göbel, Birgit; Nitsche, Ulrich

2014-01-01

Tumor xenografts in immunodeficient mice, while routinely used in cancer research, preclude studying interactions of immune and cancer cells or, if humanized by allogeneic immune cells, are of limited use for tumor-immunological questions. Here, we explore a novel way to generate cancer models with an autologous humanized immune system. We demonstrate that hematopoietic stem and progenitor cells (HSPCs) from bone marrow aspirates of non-metastasized carcinoma patients, which are taken at specialized centers for diagnostic purposes, can be used to generate a human immune system in NOD-scid IL2rγ(null) (NSG) and HLA-I expressing NSG mice (NSG-HLA-A2/HHD) comprising both, lymphoid and myeloid cell lineages. Using NSG-HLA-A2/HHD mice, we show that responsive and self-tolerant human T cells develop and human antigen presenting cells can activate human T cells. As critical factors we identified the low potential of bone marrow HSPCs to engraft, generally low HSPC numbers in patient-derived bone marrow samples, cryopreservation and routes of cell administration. We provide here an optimized protocol that uses a minimum number of HSPCs, preselects high-quality bone marrow samples defined by the number of initially isolated leukocytes and intra-femoral or intra-venous injection. In conclusion, the use of diagnostic bone marrow aspirates from non-metastasized carcinoma patients for the immunological humanization of immunodeficient mice is feasible and opens the chance for individualized analyses of anti-tumoral T cell responses. PMID:24830425

Immune humanization of immunodeficient mice using diagnostic bone marrow aspirates from carcinoma patients.

Directory of Open Access Journals (Sweden)

Melanie Werner-Klein

Full Text Available Tumor xenografts in immunodeficient mice, while routinely used in cancer research, preclude studying interactions of immune and cancer cells or, if humanized by allogeneic immune cells, are of limited use for tumor-immunological questions. Here, we explore a novel way to generate cancer models with an autologous humanized immune system. We demonstrate that hematopoietic stem and progenitor cells (HSPCs from bone marrow aspirates of non-metastasized carcinoma patients, which are taken at specialized centers for diagnostic purposes, can be used to generate a human immune system in NOD-scid IL2rγ(null (NSG and HLA-I expressing NSG mice (NSG-HLA-A2/HHD comprising both, lymphoid and myeloid cell lineages. Using NSG-HLA-A2/HHD mice, we show that responsive and self-tolerant human T cells develop and human antigen presenting cells can activate human T cells. As critical factors we identified the low potential of bone marrow HSPCs to engraft, generally low HSPC numbers in patient-derived bone marrow samples, cryopreservation and routes of cell administration. We provide here an optimized protocol that uses a minimum number of HSPCs, preselects high-quality bone marrow samples defined by the number of initially isolated leukocytes and intra-femoral or intra-venous injection. In conclusion, the use of diagnostic bone marrow aspirates from non-metastasized carcinoma patients for the immunological humanization of immunodeficient mice is feasible and opens the chance for individualized analyses of anti-tumoral T cell responses.

Voluntary Cancellation of a Pesticide Product or Use

Science.gov (United States)

A registrant can cancel the registration of a pesticide product or cancel a use from the product’s label at any time as stated in Section 6(f) of FIFRA. Learn how to request a voluntary cancellation or use deletion.

Case review analysis of operating room decisions to cancel surgery.

Science.gov (United States)

Chang, Ju-Hsin; Chen, Ke-Wei; Chen, Kuen-Bao; Poon, Kin-Shing; Liu, Shih-Kai

2014-07-23

Cancellation of surgery close to scheduled time causes a waste of healthcare resources. The current study analyzes surgery cancellations occurring after the patient has been prepared for the operating room, in order to see whether improvements in the surgery planning process may reduce the number of cancellations. In a retrospective chart review of operating room surgery cancellations during the period from 2006 to 2011, cancellations were divided into the following categories: inadequate NPO; medical; surgical; system; airway; incomplete evaluation. The relative use of these reasons in relation to patient age and surgical department was then evaluated. Forty-one percent of cancellations were for other than medical reasons. Among these, 17.7% were due to incomplete evaluation, and 8.2% were due to family issues. Sixty seven percent of cancelled cases eventually received surgery. The relative use of individual reasons for cancellation varied with patient age and surgical department. The difference between cancellations before and after anesthesia was dependent on the causes of cancellation, but not age, sex, ASA status, or follow-up procedures required. Almost half of the cancellations were not due to medical reasons, and these cancellations could be reduced by better administrative and surgical planning and better communication with the patient and/or his family.

Angiographic findings of demineralised bone matrix grafts in femoral fracture repair in canines*

International Nuclear Information System (INIS)

Kumar, R.V.S.; Ramakrishna, O.

2000-01-01

Demineralised bone matrix implants and autogenous cancellous bone grafts were evaluated in femoral fracture repair with bone loss in canines, and compared to untreated animals. Angiograms were taken at 3,6,9 and 12 weeks post- operatively using conrary-420 as contrast medium. Early angiograms showed leakage of contrast medium into soft tissue. Grafted groups showed slight hypervascularity and enhanced capillary network. At 12 Weeks the same groups observed nearly normal persistent vascular supply. Early establishment of cortices continuity and draining of contrast medium via extraosseous veins was observed in demineralized bone matrix implanted groups

20 CFR 217.26 - How to cancel an application.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false How to cancel an application. 217.26 Section... APPLICATION FOR ANNUITY OR LUMP SUM Cancellation of Application § 217.26 How to cancel an application. An application may be cancelled under the following conditions: (a) Before an annuity is awarded. The application...

Animal Models and Bone Histomorphometry: Translational Research for the Human Research Program

Science.gov (United States)

Sibonga, Jean D.

2010-01-01

This slide presentation reviews the use of animal models to research and inform bone morphology, in particular relating to human research in bone loss as a result of low gravity environments. Reasons for use of animal models as tools for human research programs include: time-efficient, cost-effective, invasive measures, and predictability as some model are predictive for drug effects.

Performance comparison of optical interference cancellation system architectures.

Science.gov (United States)

Lu, Maddie; Chang, Matt; Deng, Yanhua; Prucnal, Paul R

2013-04-10

The performance of three optics-based interference cancellation systems are compared and contrasted with each other, and with traditional electronic techniques for interference cancellation. The comparison is based on a set of common performance metrics that we have developed for this purpose. It is shown that thorough evaluation of our optical approaches takes into account the traditional notions of depth of cancellation and dynamic range, along with notions of link loss and uniformity of cancellation. Our evaluation shows that our use of optical components affords performance that surpasses traditional electronic approaches, and that the optimal choice for an optical interference canceller requires taking into account the performance metrics discussed in this paper.

Non-vascularized iliac bone grafting for scaphoid nonunion with avascular necrosis.

Science.gov (United States)

Kim, Jihyeung; Park, Jin Woo; Chung, Jeehyeok; Jeong Bae, Kee; Gong, Hyun Sik; Baek, Goo Hyun

2018-01-01

We present the surgical outcomes of non-vascularized bone grafting taken from the iliac crest in 24 patients with scaphoid nonunion and avascular necrosis. The Fisk-Fernandez technique was used in 11 patients, and cancellous bone grafting was used in 13 patients. Bony union was achieved in 22 of the 24 patients. Non-vascularized iliac bone grafting can be used for the surgical management of scaphoid nonunion with avascular necrosis. Although revascularization of the proximal fragment after surgery was not evaluated, bony union was confirmed in nearly all patients. IV.

Revascularisation of fresh compared with demineralised bone grafts in rats

DEFF Research Database (Denmark)

Solheim, E; Pinholt, E M; Talsnes, O

2001-01-01

Revascularisation of bone grafts is influenced by both the anatomical origin and the pre-implantation processing of the graft. We investigated the revascularisation by entrapment of 141Ce (cerium)-labelled microspheres in large, fresh and demineralised syngeneic grafts of predominantly cancellous...... (iliac bone) or cortical (tibial diaphysis) bone three weeks after heterotopic implantation in rats. The mean (SD) 141Ce deposition index (counts per minute (cpm) of mg recovered implant/cpm of mg host iliac bone) was higher in fresh iliac bone grafts, 0.98 (0.46) compared to that of demineralised iliac...... bone, 0.32 (0.20), p bone grafts, 0.51 (0.27), p = 0.007. We found no significant difference in the mean 141Ce deposition index between fresh tibial bone grafts and demineralised tibial bone grafts, 0.35 (0.42), p = 0.4, or between demineralised tibial grafts and demineralised...

Elective surgery cancelation on day of surgery: An endless dilemma

Directory of Open Access Journals (Sweden)

A Fayed

2016-01-01

Full Text Available Background: Cancelation of surgery is a constant agonizing dilemma for nearly all healthcare services that has been intensively investigated to find out its roots, consequences, and possible solutions. The rates of cancelation of surgery vary between centers and more so among surgical specialties with numerous reasons standing behind this phenomenon. Patients and Methods: In the current study, analysis of monthly cancelation rates from January 2009 to December 2012, and assessment of establishing new operating rooms (ORs using statistical process control charts was conducted. A detailed review of a total of 1813 cases canceled on the day of surgery from January to December 2012, to examine the various reasons of cancelation among surgical specialties. Results: The average cancelation rate was 11.1%, which dropped to 9.0% after launching of new theaters. Four reasons explained about 80% of cancelations; Patients "no show" was the leading cause of cancelation (27%. One-fourth of cancelations (24.3% were due to the need for further optimization, and the third most prominent cause of cancelation was a lack of OR time (19.5%. Unavailability of staff/equipment/implants accounted for only 0.7% of cancelations. The "no show" was the most common cause of cancelation among all surgical specialties ranging from 21% for plastic surgery to 32% in ophthalmic surgeries. Conclusion: It was confirmed that there is a unique profile of cancelation of surgery problem for every institute, an extension of infrastructure may not be the only solution. Control charts helped to enhance the general picture and are functional in monitoring and evaluating changes in the cancelation of surgery.

20 CFR 217.25 - Who may cancel an application.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Who may cancel an application. 217.25 Section... APPLICATION FOR ANNUITY OR LUMP SUM Cancellation of Application § 217.25 Who may cancel an application. An application may be cancelled by the claimant or a person described in § 217.17. If the claimant is deceased...

Creep of trabecular bone from the human proximal tibia.

Science.gov (United States)

Novitskaya, Ekaterina; Zin, Carolyn; Chang, Neil; Cory, Esther; Chen, Peter; D'Lima, Darryl; Sah, Robert L; McKittrick, Joanna

2014-07-01

Creep is the deformation that occurs under a prolonged, sustained load and can lead to permanent damage in bone. Creep in bone is a complex phenomenon and varies with type of loading and local mechanical properties. Human trabecular bone samples from proximal tibia were harvested from a 71-year old female cadaver with osteoporosis. The samples were initially subjected to one cycle load up to 1% strain to determine the creep load. Samples were then loaded in compression under a constant stress for 2h and immediately unloaded. All tests were conducted with the specimens soaked in phosphate buffered saline with proteinase inhibitors at 37 °C. Steady state creep rate and final creep strain were estimated from mechanical testing and compared with published data. The steady state creep rate correlated well with values obtained from bovine tibial and human vertebral trabecular bone, and was higher for lower density samples. Tissue architecture was analyzed by micro-computed tomography (μCT) both before and after creep testing to assess creep deformation and damage accumulated. Quantitative morphometric analysis indicated that creep induced changes in trabecular separation and the structural model index. A main mode of deformation was bending of trabeculae. Copyright © 2014 Elsevier B.V. All rights reserved.

Functional adaptation to mechanical loading in both cortical and cancellous bone is controlled locally and is confined to the loaded bones.

Science.gov (United States)

Sugiyama, Toshihiro; Price, Joanna S; Lanyon, Lance E

2010-02-01

In order to validate whether bones' functional adaptation to mechanical loading is a local phenomenon, we randomly assigned 21 female C57BL/6 mice at 19 weeks of age to one of three equal numbered groups. All groups were treated with isoflurane anesthesia three times a week for 2 weeks (approximately 7 min/day). During each anaesthetic period, the right tibiae/fibulae in the DYNAMIC+STATIC group were subjected to a peak dynamic load of 11.5 N (40 cycles with 10-s intervals between cycles) superimposed upon a static "pre-load" of 2.0 N. This total load of 13.5 N engendered peak longitudinal strains of approximately 1400 microstrain on the medial surface of the tibia at a middle/proximal site. The right tibiae/fibulae in the STATIC group received the static "pre-load" alone while the NOLOAD group received no artificial loading. After 2 weeks, the animals were sacrificed and both tibiae, fibulae, femora, ulnae and radii analyzed by three-dimensional high-resolution (5 mum) micro-computed tomography (microCT). In the DYNAMIC+STATIC group, the proximal trabecular percent bone volume and cortical bone volume at the proximal and middle levels of the right tibiae as well as the cortical bone volume at the middle level of the right fibulae were markedly greater than the left. In contrast, the left bones in the DYNAMIC+STATIC group showed no differences compared to the left or right bones in the NOLOAD or STATIC group. These microCT data were confirmed by two-dimensional examination of fluorochrome labels in bone sections which showed the predominantly woven nature of the new bone formed in the loaded bones. We conclude that the adaptive response in both cortical and trabecular regions of bones subjected to short periods of dynamic loading, even when this response is sufficiently vigorous to stimulate woven bone formation, is confined to the loaded bones and does not involve changes in other bones that are adjacent, contra-lateral or remote to them. (c) 2009 Elsevier Inc

Restoration of a Critical Mandibular Bone Defect Using Human Alveolar Bone-Derived Stem Cells and Porous Nano-HA/Collagen/PLA Scaffold

Directory of Open Access Journals (Sweden)

Xing Wang

2016-01-01

Full Text Available Periodontal bone defects occur in a wide variety of clinical situations. Adult stem cell- and biomaterial-based bone tissue regeneration are a promising alternative to natural bone grafts. Recent evidence has demonstrated that two populations of adult bone marrow mesenchymal stromal cells (BMSCs can be distinguished based on their embryonic origins. These BMSCs are not interchangeable, as bones preferentially heal using cells that share the same embryonic origin. However, the feasibility of tissue engineering using human craniofacial BMSCs was unclear. The goal of this study was to explore human craniofacial BMSC-based therapy for the treatment of localized mandibular defects using a standardized, minimally invasive procedure. The BMSCs’ identity was confirmed. Scanning electron microscopy, a cell proliferation assay, and supernatant detection indicated that the nHAC/PLA provided a suitable environment for aBMSCs. Real-time PCR and electrochemiluminescence immunoassays demonstrated that osteogenic markers were upregulated by osteogenic preinduction. Moreover, in a rabbit critical-size mandibular bone defect model, total bone formation in the nHAC/PLA + aBMSCs group was significantly higher than in the nHAC/PLA group but significantly lower than in the nHAC/PLA + preinduced aBMSCs. These findings demonstrate that this engineered bone is a valid alternative for the correction of mandibular bone defects.

Restoration of a Critical Mandibular Bone Defect Using Human Alveolar Bone-Derived Stem Cells and Porous Nano-HA/Collagen/PLA Scaffold

Science.gov (United States)

Wang, Xing; Xing, Helin; Zhang, Guilan; Wu, Xia; Zou, Xuan; Feng, Lin; Wang, Dongsheng; Li, Meng; Zhao, Jing; Du, Jianwei; Lv, Yan; E, Lingling; Liu, Hongchen

2016-01-01

Periodontal bone defects occur in a wide variety of clinical situations. Adult stem cell- and biomaterial-based bone tissue regeneration are a promising alternative to natural bone grafts. Recent evidence has demonstrated that two populations of adult bone marrow mesenchymal stromal cells (BMSCs) can be distinguished based on their embryonic origins. These BMSCs are not interchangeable, as bones preferentially heal using cells that share the same embryonic origin. However, the feasibility of tissue engineering using human craniofacial BMSCs was unclear. The goal of this study was to explore human craniofacial BMSC-based therapy for the treatment of localized mandibular defects using a standardized, minimally invasive procedure. The BMSCs' identity was confirmed. Scanning electron microscopy, a cell proliferation assay, and supernatant detection indicated that the nHAC/PLA provided a suitable environment for aBMSCs. Real-time PCR and electrochemiluminescence immunoassays demonstrated that osteogenic markers were upregulated by osteogenic preinduction. Moreover, in a rabbit critical-size mandibular bone defect model, total bone formation in the nHAC/PLA + aBMSCs group was significantly higher than in the nHAC/PLA group but significantly lower than in the nHAC/PLA + preinduced aBMSCs. These findings demonstrate that this engineered bone is a valid alternative for the correction of mandibular bone defects. PMID:27118977

Unicameral bone cyst of the lunate in an adult: case report

Directory of Open Access Journals (Sweden)

Alici Tugrul

2010-10-01

Full Text Available Abstract We report a case of a symptomatic unicameral (simple bone cyst of the lunate in a 42-year- old woman. The lesion was treated with curettage and cancellous autogenous iliac bone grafting. At five years of follow-up the wrist was pain free, there were no limitations of motion, and the radiographs showed complete obliteration of the cavity. To the best of our knowledge, no other unicameral bone cyst of the lunate has been reported in an adult. Cysts with significant cavities at the carpal bones in an adult should be approached cautiously, as they may require early curettage and bone grafting for healing, before collapse and degenerative changes occur.

Gene Expression Changes in Femoral Head Necrosis of Human Bone Tissue

Directory of Open Access Journals (Sweden)

Bernadett Balla

2011-01-01

Full Text Available Osteonecrosis of the femoral head (ONFH is the result of an interruption of the local circulation and the injury of vascular supply of bone. Multiple factors have been implicated in the development of the disease. However the mechanism of ischemia and necrosis in non-traumatic ONFH is not clear. The aim of our investigation was to identify genes that are differently expressed in ONFH vs. non-ONFH human bone and to describe the relationships between these genes using multivariate data analysis. Six bone tissue samples from ONFH male patients and 8 bone tissue samples from non-ONFH men were examined. The expression differences of selected 117 genes were analyzed by TaqMan probe-based quantitative real-time RT-PCR system. The significance test indicated marked differences in the expression of nine genes between ONFH and non-ONFH individuals. These altered genes code for collagen molecules, an extracellular matrix digesting metalloproteinase, a transcription factor, an adhesion molecule, and a growth factor. Canonical variates analysis demonstrated that ONFH and non-ONFH bone tissues can be distinguished by the multiple expression profile analysis of numerous genes controlled via canonical TGFB pathway as well as genes coding for extracellular matrix composing collagen type molecules. The markedly altered gene expression profile observed in the ONFH of human bone tissue may provide further insight into the pathogenetic process of osteonecrotic degeneration of bone.

Active noise cancellation in hearing devices

DEFF Research Database (Denmark)

2013-01-01

Disclosed is a hearing device system comprising at least one hearing aid circuitry and at least one active noise cancellation unit, the at least one hearing aid circuitry comprises at least one input transducer adapted to convert a first audio signal to an electric audio signal; a signal processor...... connected to the at least one input transducer and adapted to process said electric audio signal by at least partially correcting for a hearing loss of a user; an output transducer adapted to generate from at least said processed electric audio signal a sound pressure in an ear canal of the user, whereby...... the generated sound pressure is at least partially corrected for the hearing loss of the user; ; the at least one active noise cancellation unit being adapted to provide an active noise cancellation signal adapted to perform active noise cancellation of an acoustical signal entering the ear canal in addition...

Effects of long-term estrogen replacement therapy on bone turnover in periarticular tibial osteophytes in surgically postmenopausal cynomolgus monkeys

OpenAIRE

Olson, Erik J.; Lindgren, Bruce R.; Carlson, Cathy S.

2007-01-01

The aims of the present study were to assess the effects of long-term estrogen replacement therapy (ERT) on size and indices of bone turnover in periarticular osteophytes in ovariectomized cynomolgus monkeys and to compare dynamic indices of bone turnover in osteophyte bone with those of subchondral bone (SCB) and epiphyseal/metaphyseal cancellous (EMC) bone. One hundred sixty-five adult female cynomolgus macaques were bilaterally ovariectomized and randomly divided into three age- and weight...

Day of Surgery Admission in Total Joint Arthroplasty: Why Are Surgeries Cancelled? An Analysis of 3195 Planned Procedures and 114 Cancellations

Directory of Open Access Journals (Sweden)

David M. Dalton

2016-01-01

Full Text Available Background. Day of surgery admission (DOSA is becoming standard practice as a means of reducing cost in total joint arthroplasty. Aims. The aim of our study was to audit the use of DOSA in a specialty hospital and identify reasons for cancellation. Methods. A retrospective study of patients presenting for hip or knee arthroplasty between 2008 and 2013 was performed. All patients were assessed at the preoperative assessment clinic (PAC. Results. Of 3195 patients deemed fit for surgery, 114 patients (3.5% had their surgery cancelled. Ninety-two cancellations (80% were due to the patient being deemed medically unsuitable for surgery by the anaesthetist. Cardiac disease was the most common reason for cancellation (n=27, followed by pulmonary disease (n=22. 77 patients (67.5% had their operation rescheduled and successfully performed in our institution at a later date. Conclusion. DOSA is associated with a low rate of cancellations on the day of surgery. Patients with cardiorespiratory comorbidities are at greatest risk of cancellation.

Is the corticomedullary index valid to distinguish human from nonhuman bones: a multislice computed tomography study.

Science.gov (United States)

Rérolle, Camille; Saint-Martin, Pauline; Dedouit, Fabrice; Rousseau, Hervé; Telmon, Norbert

2013-09-10

The first step in the identification process of bone remains is to determine whether they are of human or nonhuman origin. This issue may arise when only a fragment of bone is available, as the species of origin is usually easily determined on a complete bone. The present study aims to assess the validity of a morphometric method used by French forensic anthropologists to determine the species of origin: the corticomedullary index (CMI), defined by the ratio of the diameter of the medullary cavity to the total diameter of the bone. We studied the constancy of the CMI from measurements made on computed tomography images (CT scans) of different human bones, and compared our measurements with reference values selected in the literature. The measurements obtained on CT scans at three different sites of 30 human femurs, 24 tibias, and 24 fibulas were compared between themselves and with the CMI reference values for humans, pigs, dogs and sheep. Our results differed significantly from these reference values, with three exceptions: the proximal quarter of the femur and mid-fibular measurements for the human CMI, and the proximal quarter of the tibia for the sheep CMI. Mid-tibial, mid-femoral, and mid-fibular measurements also differed significantly between themselves. Only 22.6% of CT scans of human bones were correctly identified as human. We concluded that the CMI is not an effective method for determining the human origin of bone remains. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

40 CFR 152.99 - Petitions to cancel registration.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Petitions to cancel registration. 152... Submitters' Rights § 152.99 Petitions to cancel registration. An original data submitter may petition the Agency to deny or cancel the registration of a product in accordance with this section if he has...

Using Comics to Communicate Legal Contract Cancellation

OpenAIRE

Marietjie Botes

2017-01-01

This article investigates how comics can be used to adequately communicate the correct process of contract cancellation and whether comics can enhance understanding of the legal process. A survey of pre-owned vehicle buyers of various levels of education in Pretoria, South Africa found that when comics are used to communicate contract cancellation, a significant increase in the comprehension of the legal cancellation process occurs. The results may influence how contracting parties may choose...

Evaluation of tibolone administration in bone architectural by MicroCT

Energy Technology Data Exchange (ETDEWEB)

Carvalho, A. C. B.; Henriques, H. N. [Patology Dept., Fluminense Federal Univ., Niteroi (Brazil); Granjeiro, J. M. [Molecular and Cell Biology Dept., Fluminense Federal Univ., Niteroi, Rio de Janeiro (Brazil); Guzman-Silva, M. A. [Patology Dept., Fluminense Federal Univ., Niteroi (Brazil); Lopes, R. T.; Lima, I. [Nuclear Engineering Laboratory, Federal Univ. of Rio de Janeiro (Brazil)

2011-07-01

Elderly women are at higher risk for hip fracture because of additional and relatively rapid bone loss due to estrogen deficiency by loss of the ovarian function and a longer average life span than men. The early application of agents that suppress the increase in bone turnover due to estrogen deficiency is essential to prevent bone loss and reduce the risk of osteoporosis. Some advanced imaging techniques may be required to investigate osteoporosis. X-ray micro-computed tomography has been used to generate high-resolution 3D images of cancellous and cortical bone morphology from normal and pathologic human and animal specimens. The aim of this study is to verify the effects of tibolone administration by evaluating the trabecular bone region. The experiment was performed on two groups of rats previously ovariectomized in which one received tibolone while the other did not. Tibolone administration (1 mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs were collected. The scan was obtained using a Hamamatsu 10 Mp camera with a pixel size of 11.59 {mu}m and trabecular region in the right femoral head were quantified. All results were statistically evaluated with significance set at P<0.05%. Tibolone administration was shown to be beneficial in some analysis of the femoral head, performing higher bone volume and reducing the porosity when compared to ovariectomized. It can be concluded that tibolone administered to ovariectomized rats significantly preserved bone mass in the femoral head and microtomography was an efficient method to identify bone loss process and to evaluate potential therapies, as tibolone administration. (authors)

Evaluation of tibolone administration in bone architectural by MicroCT

International Nuclear Information System (INIS)

Carvalho, A. C. B.; Henriques, H. N.; Granjeiro, J. M.; Guzman-Silva, M. A.; Lopes, R. T.; Lima, I.

2011-01-01

Elderly women are at higher risk for hip fracture because of additional and relatively rapid bone loss due to estrogen deficiency by loss of the ovarian function and a longer average life span than men. The early application of agents that suppress the increase in bone turnover due to estrogen deficiency is essential to prevent bone loss and reduce the risk of osteoporosis. Some advanced imaging techniques may be required to investigate osteoporosis. X-ray micro-computed tomography has been used to generate high-resolution 3D images of cancellous and cortical bone morphology from normal and pathologic human and animal specimens. The aim of this study is to verify the effects of tibolone administration by evaluating the trabecular bone region. The experiment was performed on two groups of rats previously ovariectomized in which one received tibolone while the other did not. Tibolone administration (1 mg/day) began thirty days after the ovariectomy and the treatment remained for five months. At last, the animals were euthanized and femurs were collected. The scan was obtained using a Hamamatsu 10 Mp camera with a pixel size of 11.59 μm and trabecular region in the right femoral head were quantified. All results were statistically evaluated with significance set at P<0.05%. Tibolone administration was shown to be beneficial in some analysis of the femoral head, performing higher bone volume and reducing the porosity when compared to ovariectomized. It can be concluded that tibolone administered to ovariectomized rats significantly preserved bone mass in the femoral head and microtomography was an efficient method to identify bone loss process and to evaluate potential therapies, as tibolone administration. (authors)

Development of a Human Cranial Bone Surrogate for Impact Studies

International Nuclear Information System (INIS)

Roberts, Jack C.; Merkle, Andrew C.; Carneal, Catherine M.; Voo, Liming M.; Johannes, Matthew S.; Paulson, Jeff M.; Tankard, Sara; Uy, O. Manny

2013-01-01

In order to replicate the fracture behavior of the intact human skull under impact it becomes necessary to develop a material having the mechanical properties of cranial bone. The most important properties to replicate in a surrogate human skull were found to be the fracture toughness and tensile strength of the cranial tables as well as the bending strength of the three-layer (inner table-diplöe-outer table) architecture of the human skull. The materials selected to represent the surrogate cranial tables consisted of two different epoxy resins systems with random milled glass fiber to enhance the strength and stiffness and the materials to represent the surrogate diplöe consisted of three low density foams. Forty-one three-point bending fracture toughness tests were performed on nine material combinations. The materials that best represented the fracture toughness of cranial tables were then selected and formed into tensile samples and tested. These materials were then used with the two surrogate diplöe foam materials to create the three-layer surrogate cranial bone samples for three-point bending tests. Drop tower tests were performed on flat samples created from these materials and the fracture patterns were very similar to the linear fractures in pendulum impacts of intact human skulls, previously reported in the literature. The surrogate cranial tables had the quasi-static fracture toughness and tensile strength of 2.5 MPa√ m and 53 ± 4.9 MPa, respectively, while the same properties of human compact bone were 3.1 ± 1.8 MPa√ m and 68 ± 18 MPa, respectively. The cranial surrogate had a quasi-static bending strength of 68 ± 5.7 MPa, while that of cranial bone was 82 ± 26 MPa. This material/design is currently being used to construct spherical shell samples for drop tower and ballistic tests.

Calcium citrate: a new biomaterial that can enhance bone formation in situ

Directory of Open Access Journals (Sweden)

WANG Li-ming

2012-11-01

Full Text Available 【Abstract】 Objective: To investigate the effect of a new biomaterial combining calcium citrate and recombinant human bone morphogenetic protein-2 (rhBMP-2 on bone regeneration in a bone defect rabbit model. Methods: Totally 30 male New Zealand white rabbits were randomly and equally divided into calcium citrate-rhBMP-2 (CC-rhBMP-2 group and rhBMP-2 only group. Two 10 mm-long and 5 mm-deep bone defects were respec-tively created in the left and right femoral condyles of the rabbits. Subsequently 5 pellets of calcium citrate (10 mg combined with rhBMP-2 (2 mg or rhBMP-2 alone were im-planted into the bone defects and compressed with cotton swab. Bone granules were obtained at 2, 4 and 6 weeks after procedure and received histological analysis. LSD t-test and a subsequent t-test were adopted for statistical analysis. Results: Histomorphometric analysis revealed newly formed bones, and calcium citrate has been absorbed in the treatment group. The percent of newly formed bone area in femoral condyle in control group and CC-rhBMP-2 group was respectively 31.73%±1.26% vs 48.21%±2.37% at 2 weeks; 43.40%±1.65% vs 57.32%±1.47% at 4 weeks, and 51.32%±7.80% vs 66.74%±4.05% at 6 weeks (P<0.05 for all. At 2 weeks, mature cancellous bone was observed to be already formed in the treatment group. Conclusion: From this study, it can be concluded that calcium citrate combined with rhBMP-2 signifcantly en-hances bone regeneration in bone defects. This synthetic gelatin matrix stimulates formation of new bone and bone marrow in the defect areas by releasing calcium ions. Key words: Bone morphogenetic protein-2; Biocompatible materials; Calcium citrate; Gelatin

77 FR 70788 - National Advisory Council on Migrant Health; Cancellation of Meeting

Science.gov (United States)

2012-11-27

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Health Resources and Services Administration National Advisory Council on Migrant Health; Cancellation of Meeting Name: National Advisory Council on Migrant....m. STATUS: The meeting of the National Advisory Council on Migrant Health, scheduled for December 4...

Photonic-Enabled RF Canceller with Tunable Time-Delay Taps

Science.gov (United States)

2016-12-05

Photonic -Enabled RF Canceller with Tunable Time-Delay Taps Kenneth E. Kolodziej, Sivasubramaniam Yegnanarayanan, Bradley T. Perry MIT Lincoln...canceller design that uses photonics and a vector modulator architecture to provide a high number of canceller taps with tunable time-delays, which allow...microwave photonics , RF cancellation. I. INTRODUCTION In-Band Full-Duplex (IBFD) technologies are being consid- ered for 5th generation (5G) wireless

Cell and protein compatible 3D bioprinting of mechanically strong constructs for bone repair

International Nuclear Information System (INIS)

Sawkins, M J; Mistry, P; Shakesheff, K M; Yang, J; Brown, B N; Bonassar, L J

2015-01-01

Rapid prototyping of bone tissue engineering constructs often utilizes elevated temperatures, organic solvents and/or UV light for materials processing. These harsh conditions may prevent the incorporation of cells and therapeutic proteins in the fabrication processes. Here we developed a method for using bioprinting to produce constructs from a thermoresponsive microparticulate material based on poly(lactic-co-glycolic acid) at ambient conditions. These constructs could be engineered with yield stresses of up to 1.22 MPa and Young’s moduli of up to 57.3 MPa which are within the range of properties of human cancellous bone. Further study showed that protein-releasing microspheres could be incorporated into the bioprinted constructs. The release of the model protein lysozyme from bioprinted constructs was sustainted for a period of 15 days and a high degree of protein activity could be measured up to day 9. This work suggests that bioprinting is a viable route to the production of mechanically strong constructs for bone repair under mild conditions which allow the inclusion of viable cells and active proteins. (paper)

Human Cementum Protein 1 induces expression of bone and cementum proteins by human gingival fibroblasts

International Nuclear Information System (INIS)

Carmona-Rodriguez, Bruno; Alvarez-Perez, Marco Antonio; Narayanan, A. Sampath; Zeichner-David, Margarita; Reyes-Gasga, Jose; Molina-Guarneros, Juan; Garcia-Hernandez, Ana Lilia; Suarez-Franco, Jose Luis; Chavarria, Ivet Gil; Villarreal-Ramirez, Eduardo; Arzate, Higinio

2007-01-01

We recently presented evidence showing that a human cementoblastoma-derived protein, named Cementum Protein 1 (CEMP1) may play a role as a local regulator of cementoblast differentiation and cementum-matrix mineralization. This protein was shown to be expressed by cementoblasts and progenitor cells localized in the periodontal ligament. In this study we demonstrate that transfection of CEMP1 into human gingival fibroblasts (HGF) induces mineralization and expression of bone and cementum-matrix proteins. The transfected HGF cells had higher alkaline phosphatase activity and proliferation rate and they expressed genes for alkaline phosphatase, bone sialoprotein, osteocalcin, osteopontin, the transcription factor Runx2/Cbfa1, and cementum attachment protein (CAP). They also produced biological-type hydroxyapatite. These findings indicate that the CEMP1 might participate in differentiation and mineralization of nonosteogenic cells, and that it might have a potential function in cementum and bone formation

Scanning electron microscopy of bone.

Science.gov (United States)

Boyde, Alan

2012-01-01

This chapter described methods for Scanning Electron Microscopical imaging of bone and bone cells. Backscattered electron (BSE) imaging is by far the most useful in the bone field, followed by secondary electrons (SE) and the energy dispersive X-ray (EDX) analytical modes. This chapter considers preparing and imaging samples of unembedded bone having 3D detail in a 3D surface, topography-free, polished or micromilled, resin-embedded block surfaces, and resin casts of space in bone matrix. The chapter considers methods for fixation, drying, looking at undersides of bone cells, and coating. Maceration with alkaline bacterial pronase, hypochlorite, hydrogen peroxide, and sodium or potassium hydroxide to remove cells and unmineralised matrix is described in detail. Attention is given especially to methods for 3D BSE SEM imaging of bone samples and recommendations for the types of resin embedding of bone for BSE imaging are given. Correlated confocal and SEM imaging of PMMA-embedded bone requires the use of glycerol to coverslip. Cathodoluminescence (CL) mode SEM imaging is an alternative for visualising fluorescent mineralising front labels such as calcein and tetracyclines. Making spatial casts from PMMA or other resin embedded samples is an important use of this material. Correlation with other imaging means, including microradiography and microtomography is important. Shipping wet bone samples between labs is best done in glycerol. Environmental SEM (ESEM, controlled vacuum mode) is valuable in eliminating -"charging" problems which are common with complex, cancellous bone samples.

Human bone marrow stem cell-encapsulating calcium phosphate scaffolds for bone repair

Science.gov (United States)

Weir, Michael D.; Xu, Hockin H.K.

2010-01-01

Due to its injectability and excellent osteoconductivity, calcium phosphate cement (CPC) is highly promising for orthopedic applications. However, a literature search revealed no report on human bone marrow mesenchymal stem cell (hBMSC) encapsulation in CPC for bone tissue engineering. The aim of this study was to encapsulate hBMSCs in alginate hydrogel beads and then incorporate them into CPC, CPC–chitosan and CPC–chitosan–fiber scaffolds. Chitosan and degradable fibers were used to mechanically reinforce the scaffolds. After 21 days, that the percentage of live cells and the cell density of hBMSCs inside CPC-based constructs matched those in alginate without CPC, indicating that the CPC setting reaction did not harm the hBMSCs. Alkaline phosphate activity increased by 8-fold after 14 days. Mineral staining, scanning electron microscopy and X-ray diffraction confirmed that apatitic mineral was deposited by the cells. The amount of hBMSC-synthesized mineral in CPC–chitosan–fiber matched that in CPC without chitosan and fibers. Hence, adding chitosan and fibers, which reinforced the CPC, did not compromise hBMSC osteodifferentiation and mineral synthesis. In conclusion, hBMSCs were encapsulated in CPC and CPC–chitosan–fiber scaffolds for the first time. The encapsulated cells remained viable, osteodifferentiated and synthesized bone minerals. These self-setting, hBMSC-encapsulating CPC-based constructs may be promising for bone tissue engineering applications. PMID:20451676

Impact of radiation history, gender and age on bone quality in sites for orthodontic skeletal anchorage device placement.

Science.gov (United States)

Konermann, A; Appel, T; Wenghoefer, M; Sirokay, S; Dirk, C; Jäger, A; Götz, W

2015-05-01

Stability of orthodontic miniscrew implants is prerequisite to their success and durability in orthodontic treatment. As investigations revealed a positive correlation of miniscrew stability to periimplant bone quality, it has been the aim of this study to analyze the bone structure of resection preparations of human mandibles histologically by investigating the samples according to age, gender and exposure to radiotherapy. Inflammation- and tumor-free alveolar bone sections from human mandibles (n = 31) with previously diagnosed carcinoma, chronic osteomyelitis or cysts were analyzed histomorphologically and histomorphometrically as to the dimension of trabeculae in cancellous areas. Group A investigated the impact of a history of radiation therapy, group B of gender and group C contrasted biopsies from individuals aging under 60 or over 60 years. Statistics were performed using the Kruskal-Wallis-test. Radiation, gender and age did not significantly influence bone density. The mean bone density averaged 40.7 ± 15.0% of spongiosa for the total collective with a median age of 58.4 years ± 14.7 years. Our findings provide new information on bone quality, thus contributing to a more precise evaluation of the parameters affecting and those not affecting miniscrew implant stability. On the basis of these results, the formulation of clinical guidelines for risk assessment of therapeutic approaches in patients prior to insertion of orthodontic skeletal anchorage devices seems to be conceivable. Copyright © 2014 Elsevier GmbH. All rights reserved.

78 FR 27974 - National Advisory Council on Migrant Health; Cancellation of Meeting

Science.gov (United States)

2013-05-13

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Health Resources and Services Administration National Advisory Council on Migrant Health; Cancellation of Meeting Name: National Advisory Council on Migrant.... Status: The meeting of the National Advisory Council on Migrant Health, scheduled for May 21 and 22, 2013...

RATES OF PHOTOSPHERIC MAGNETIC FLUX CANCELLATION MEASURED WITH HINODE

International Nuclear Information System (INIS)

Park, Soyoung; Chae, Jongchul; Litvinenko, Yuri E.

2009-01-01

Photospheric magnetic flux cancellation on the Sun is generally believed to be caused by magnetic reconnection occurring in the low solar atmosphere. Individual canceling magnetic features are observationally characterized by the rate of flux cancellation. The specific cancellation rate, defined as the rate of flux cancellation divided by the interface length, gives an accurate estimate of the electric field in the reconnecting current sheet. We have determined the specific cancellation rate using the magnetograms taken by the Solar Optical Telescope (SOT) aboard the Hinode satellite. The specific rates determined with SOT turned out to be systematically higher than those based on the data taken by the Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory. The median value of the specific cancellation rate was found to be 8 x 10 6 G cm s -1 -a value four times that obtained from the MDI data. This big difference is mainly due to a higher angular resolution and better sensitivity of the SOT, resulting in magnetic fluxes up to five times larger than those obtained from the MDI. The higher rates of flux cancellation correspond to either faster inflows or stronger magnetic fields of the reconnection inflow region, which may have important consequences for the physics of photospheric magnetic reconnection.

Bone strength and material properties of the glenoid

DEFF Research Database (Denmark)

Frich, Lars Henrik; Jensen, N.C.; Odgaard, A.

1997-01-01

of bone specimens harvested from the central part of the glenoid subchondral area. The elastic modulus varied from approximately 100 MPa at the glenoid bare area to 400 MPa at the superior part of the glenoid. With the elastic constants used a predictor of the mechanical anisotropy, the average anisotropy...... ratio was 5.2, indicating strong anisotropy. The apparent density was an average 0.35 gr. cm-3, and the Poisson ratio averaged 0.263. According to our findings the anisotropy of the glenoid cancellous bone, details concerning the strength distribution, and the load-bearing function of the cortical shell......The quality of the glenoid bone is important to a successful total shoulder replacement. Finite element models have been used to model the response of the glenoid bone to an implanted prosthesis. Because very little is known about the bone strength and the material properties at the glenoid...

Bone grafting in surgery about the foot and ankle: indications and techniques.

Science.gov (United States)

Fitzgibbons, Timothy C; Hawks, Michael A; McMullen, Scott T; Inda, David J

2011-02-01

Bone grafting is a common procedure in foot and ankle surgery. Historically, autogenous bone graft has most often been harvested from the ipsilateral iliac crest. However, other sites offer similar volumes of cancellous bone and are associated with fewer complications. The ipsilateral proximal tibia, distal tibia, and calcaneus provide adequate amounts of bone graft material for most arthrodesis procedures about the foot and ankle. Emerging techniques have enabled the development of a seemingly unlimited supply of alternative bone graft materials with osteoconductive properties. The osteoprogenitor cells in bone marrow aspirates can be concentrated by use of selective retention systems. These aspirate-matrix composites may be combined with allograft preparations, resulting in a product that promotes osteoconduction, osteoinduction, and osteogenesis with limited morbidity.

Association between in vivo bone formation and ex vivo migratory capacity of human bone marrow stromal cells

DEFF Research Database (Denmark)

Andersen, Rikke K.; Zaher, Walid; Larsen, Kenneth Hauberg

2015-01-01

INTRODUCTION: There is a clinical need for developing systemic transplantation protocols for use of human skeletal stem cells (also known bone marrow stromal stem cells) (hBMSC) in tissue regeneration. In systemic transplantation studies, only a limited number of hBMSC home to injured tissues...... populations derived from telomerized hBMSC (hBMSC-TERT) with variable ability to form heterotopic bone when implanted subcutaneously in immune deficient mice. In vitro transwell migration assay was used and the in vivo homing ability of transplanted hBMSC to bone fractures in mice was visualized...... suggesting that only a subpopulation of hBMSC possesses "homing" capacity. Thus, we tested the hypothesis that a subpopulation of hBMSC defined by ability to form heterotopic bone in vivo, is capable of homing to injured bone. METHODS: We tested ex vivo and in vivo homing capacity of a number of clonal cell...

Microstructural properties of trabecular bone autografts: comparison of men and women with and without osteoporosis.

Science.gov (United States)

Xie, Fen; Zhou, Bin; Wang, Jian; Liu, Tang; Wu, Xiyu; Fang, Rui; Kang, Yijun; Dai, Ruchun

2018-03-05

The microstructure of autologous bone grafts from men over 50 years old and postmenopausal women undergoing spinal fusion were evaluated using micro-CT. We demonstrated postmenopausal women, especially those with osteoporosis (OP) presented more serious microarchitectural deterioration of bone grafts. This study was undertaken to determine microstructural properties of cancellous bone used as autologous bone grafts from osteoporosis patients undergoing lumbar fusion by comparing microstructural indices to controls. Cancellous bone specimens from spinous processes were obtained from 41 postmenopausal women (osteoporosis women, n = 19; controls, n = 22) and 26 men over 50 years old (osteoporosis men, n = 8; controls, n = 18) during lumbar fusion surgery. The microstructural parameters were measured using micro-CT. Significant difference in bone volume fraction (BV/TV), specific bone surface (BS/BV), trabecular thickness (Tb.Th), and structure model index (SMI) value existed between postmenopausal women with OP and controls. Significant difference in trabecular number (Tb.N) existed between men over 50 years old with OP and controls. Postmenopausal women exhibited lower BV/TV, Tb.Th, and higher SMI value than men over 50 years old. Postmenopausal women with OP exhibited lower BV/TV, Tb.Th, and higher BS/BV than men over 50 years old with OP. Post-menopausal women and older men with OP have worse bone quality in autografts than non-osteoporotic men and women. Postmenopausal women with OP presented serious microarchitectural deterioration in older population.

Human decellularized bone scaffolds from aged donors show improved osteoinductive capacity compared to young donor bone.

Directory of Open Access Journals (Sweden)

Christopher A Smith

Full Text Available To improve the safe use of allograft bone, decellularization techniques may be utilized to produce acellular scaffolds. Such scaffolds should retain their innate biological and biomechanical capacity and support mesenchymal stem cell (MSC osteogenic differentiation. However, as allograft bone is derived from a wide age-range, this study aimed to determine whether donor age impacts on the ability an osteoinductive, acellular scaffold produced from human bone to promote the osteogenic differentiation of bone marrow MSCs (BM-MSC. BM-MSCs from young and old donors were seeded on acellular bone cubes from young and old donors undergoing osteoarthritis related hip surgery. All combinations resulted in increased osteogenic gene expression, and alkaline phosphatase (ALP enzyme activity, however BM-MSCs cultured on old donor bone displayed the largest increases. BM-MSCs cultured in old donor bone conditioned media also displayed higher osteogenic gene expression and ALP activity than those exposed to young donor bone conditioned media. ELISA and Luminex analysis of conditioned media demonstrated similar levels of bioactive factors between age groups; however, IGF binding protein 1 (IGFBP1 concentration was significantly higher in young donor samples. Additionally, structural analysis of old donor bone indicated an increased porosity compared to young donor bone. These results demonstrate the ability of a decellularized scaffold produced from young and old donors to support osteogenic differentiation of cells from young and old donors. Significantly, the older donor bone produced greater osteogenic differentiation which may be related to reduced IGFBP1 bioavailability and increased porosity, potentially explaining the excellent clinical results seen with the use of allograft from aged donors.

Bone properties of the humeral head and resistance to screw cutout

DEFF Research Database (Denmark)

Frich, L. H.; Jensen, N. C.

2014-01-01

Surgical treatment of fractures involving the proximal humeral head is hampered by complications. Screw cutout is the major pitfall seen in connection with rigid plating. We have exploited a bony explanation for this phenomenon. Materials and Methods: We examined the convex surface of the humeral...... sectioning technique. Results: The bone strength and bone density correlated well and revealed large regional variations across the humeral head. Bone strength and stiffness of the trabecular bone came to a maximum in the most medial anterior and central parts of the humeral head, where strong textural...... screw directions will predictably place screws in areas of the humeral head comprising low density and low strength cancellous bone. New concepts of plates and plating techniques for the surgical treatment of complex fractures of the proximal humerus should take bone distribution, strength...

[Progress of Masquelet technique to repair bone defect].

Science.gov (United States)

Yin, Qudong; Sun, Zhenzhong; Gu, Sanjun

2013-10-01

To summarize the progress of Masquelet technique to repair bone defect. The recent literature concerning the application of Masquelet technique to repair bone defect was extensively reviewed and summarized. Masquelet technique involves a two-step procedure. First, bone cement is used to fill the bone defect after a thorough debridement, and an induced membrane structure surrounding the spacer formed; then the bone cement is removed after 6-8 weeks, and rich cancellous bone is implanted into the induced membrane. Massive cortical bone defect is repaired by new bone forming and consolidation. Experiments show that the induced membrane has vascular system and is also rich in vascular endothelial growth factor, transforming growth factor beta1, bone morphogenetic protein 2, and bone progenitor cells, so it has osteoinductive property; satisfactory results have been achieved in clinical application of almost all parts of defects, various types of bone defect and massive defect up to 25 cm long. Compared with other repair methods, Masquelet technique has the advantages of reliable effect, easy to operate, few complications, low requirements for recipient site, and wide application. Masquelet technique is an effective method to repair bone defect and is suitable for various types of bone defect, especially for bone defects caused by infection and tumor resection.

Recombinant human bone morphogenetic protein 2 in augmentation procedures: case reports.

Science.gov (United States)

Luiz, Jaques; Padovan, Luis Eduardo Marques; Claudino, Marcela

2014-01-01

To successfully rehabilitate edentulous patients using endosseous implants, there must be enough available bone. Several techniques have been proposed for augmentation of sites with insufficient bone volume. Although autogenous bone has long been considered the gold standard for such procedures, the limited availability of graft material and a high morbidity rate are potential disadvantages of this type of graft. An alternative is to use recombinant human bone morphogenetic protein 2 (rhBMP-2), which is able to support bone regeneration in the oral environment. These cases demonstrate the applicability of rhBMP-2 in maxillary sinus elevation and augmentation procedures in the maxilla to enable dental implant placement. The use of rhBMP-2 in alveolar augmentation procedures had several clinical benefits for these patients.

Recombinant human bone morphogenetic protein-2 in the treatment of bone fractures

Directory of Open Access Journals (Sweden)

Neil Ghodadra

2008-09-01

Full Text Available Neil Ghodadra, Kern SinghDepartment of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USAAbstract: Over one million fractures occur per year in the US and are associated with impaired healing increasing patient morbidity, stress, and economic costs. Despite improvements in surgical technique, internal fixation, and understanding of biologics, fracture healing is delayed or impaired in up to 4% of all fractures. Complications due to impaired fracture healing present therapeutic challenges to the orthopedic surgeon and often lead to chronic functional and psychological disability for the patient. As a result, it has become clinically desirable to augment mechanical fixation with biologic strategies in order to accelerate osteogenesis and promote successful arthrodesis. The discovery of bone morphogenic protein (BMP has been pivotal in understanding the biology of fracture healing and has been a source of intense clinical research as an adjunct to fracture treatment. Multiple in vitro and in vivo studies in animals have elucidated the complex biologic interactions between BMPs and cellular receptors and have convincingly demonstrated rhBMP-2 to be a safe, effective treatment option to enhance bone healing. Multiple clinical trials in trauma surgery have provided level 1 evidence for the use of rhBMP-2 as a safe and effective treatment of fractures. Human clinical trials have provided further insight into BMP-2 dosage, time course, carriers, and efficacy in fracture healing of tibial defects. These promising results have provided hope that a new biologic field of technology has emerged as a useful adjunct in the treatment of skeletal injuries and conditions.Keywords: bone morphogenic protein-2, bone fracture, bone healing

CD146/MCAM defines functionality of human bone marrow stromal stem cell populations

DEFF Research Database (Denmark)

Harkness, Linda; Zaher, Walid; Ditzel, Nicholas

2016-01-01

BACKGROUND: Identification of surface markers for prospective isolation of functionally homogenous populations of human skeletal (stromal, mesenchymal) stem cells (hMSCs) is highly relevant for cell therapy protocols. Thus, we examined the possible use of CD146 to subtype a heterogeneous hMSC...... population. METHODS: Using flow cytometry and cell sorting, we isolated two distinct hMSC-CD146(+) and hMSC-CD146(-) cell populations from the telomerized human bone marrow-derived stromal cell line (hMSC-TERT). Cells were examined for differences in their size, shape and texture by using high...... and adipocytes on the basis of gene expression and protein production of lineage-specific markers. In vivo, hMSC-CD146(+) and hMSC-CD146(-) cells formed bone and bone marrow organ when implanted subcutaneously in immune-deficient mice. Bone was enriched in hMSC-CD146(-) cells (12.6 % versus 8.1 %) and bone...

Does PEEK/HA Enhance Bone Formation Compared With PEEK in a Sheep Cervical Fusion Model?

Science.gov (United States)

Walsh, William R; Pelletier, Matthew H; Bertollo, Nicky; Christou, Chris; Tan, Chris

2016-11-01

Polyetheretherketone (PEEK) has a wide range of clinical applications but does not directly bond to bone. Bulk incorporation of osteoconductive materials including hydroxyapatite (HA) into the PEEK matrix is a potential solution to address the formation of a fibrous tissue layer between PEEK and bone and has not been tested. Using in vivo ovine animal models, we asked: (1) Does PEEK-HA improve cortical and cancellous bone ongrowth compared with PEEK? (2) Does PEEK-HA improve bone ongrowth and fusion outcome in a more challenging functional ovine cervical fusion model? The in vivo responses of PEEK-HA Enhanced and PEEK-OPTIMA ® Natural were evaluated for bone ongrowth in the form of dowels implanted in the cancellous and cortical bone of adult sheep and examined at 4 and 12 weeks as well as interbody cervical fusion at 6, 12, and 26 weeks. The bone-implant interface was evaluated with radiographic and histologic endpoints for a qualitative assessment of direct bone contact of an intervening fibrous tissue later. Gamma-irradiated cortical allograft cages were evaluated as well. Incorporating HA into the PEEK matrix resulted in more direct bone apposition as opposed to the fibrous tissue interface with PEEK alone in the bone ongrowth as well as interbody cervical fusions. No adverse reactions were found at the implant-bone interface for either material. Radiography and histology revealed resorption and fracture of the allograft devices in vivo. Incorporating HA into PEEK provides a more favorable environment than PEEK alone for bone ongrowth. Cervical fusion was improved with PEEK-HA compared with PEEK alone as well as allograft bone interbody devices. Improving the bone-implant interface with a PEEK device by incorporating HA may improve interbody fusion results and requires further clinical studies.

Dispersion cancellation in a triple Laue interferometer

International Nuclear Information System (INIS)

Lemmel, Hartmut

2014-01-01

The concept of dispersion cancellation has been established in light optics to improve the resolution of interferometric measurements on dispersive media. Odd order dispersion cancellation allows to measure phase shifts without defocusing the interferometer due to wave packet displacements, while even order dispersion cancellation allows to measure time lags without losing resolution due to wave packet spreading. We report that either type of dispersion cancellation can be realized very easily in a triple Laue interferometer. Such interferometers are Mach–Zehnder interferometers based on Bragg diffraction, and are commonly used for neutrons and x-rays. Although the first x-ray interferometer was built nearly five decades ago, the feature of dispersion cancellation hasn't been recognized so far because the concept was hardly known in the neutron and x-ray community. However, it explains right away the surprising decoupling of phase shift and spatial displacement that we have discovered recently in neutron interferometry (Lemmel and Wagh 2010 Phys. Rev. A 82 033626). Furthermore, this article might inspire the light optics community to consider whether a triple Laue interferometer for laser light would be useful and feasible. We explain how dispersion cancellation works in neutron interferometry, and we describe the setup rigorously by solving the Schrödinger equation and by calculating the path integral. We point out, that the latter has to be evaluated with special care since in our setup the beam trajectory moves with respect to the crystal lattice of the interferometer. (paper)

No effect of Osteoset, a bone graft substitute, on bone healing in humans: a prospective randomized double-blind study

DEFF Research Database (Denmark)

Petruskevicius, Juozas; Nielsen, Mette Strange; Kaalund, Søren

2002-01-01

We studied the effects of a newly marketed bone substitute, Osteoset, on bone healing in a tibial defect in humans. 20 patients undergoing an ACL (anterior cruciate ligament) reconstruction with bone-patella tendon-bone graft were block-randomized into 2 groups of 10 each. In the treatment group......, the tibial defect was filled manually with Osteoset pellets, in the control group the defect was left empty. CTs of the defect were taken on the first day after the operation, 6 weeks, 3 and 6 months postoperatively. We found about the same amount of bone in the defect in the Osteoset and control groups...... after 6 weeks, 3, and 6 months. In the control group, but not in the Osteoset group, the bone volume increased from 6 weeks to 3 months. The Osteoset pellets were almost resorbed after 6 weeks....

30 CFR 280.27 - When may MMS cancel my permit?

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When may MMS cancel my permit? 280.27 Section... Part Interrupted Activities § 280.27 When may MMS cancel my permit? The RD may cancel a permit at any time. (a) If we cancel your permit, the RD will advise you by certified or registered mail 30 days...

Bone induction by surface-double-modified true bone ceramics in vitro and in vivo

International Nuclear Information System (INIS)

Li, Jingfeng; Chen, Liaobin; Deng, Yu; Zheng, Qixin; Guo, Xiaodong; Zou, Zhenwei; Liu, Yudong; Lan, Shenghui

2013-01-01

True bone ceramic (TBC), obtained by twice sintering fresh bovine cancellous bone at high temperatures, is an osteoconductive and bioactive bone substitute material that exhibits excellent biocompatibility with hard tissue. The authors have previously synthesized a novel BMP-2-related peptide, P24, and found that it could enhance the osteoblastic differentiation of cells. The objective of the present study was to construct a double-modified TBC via mineralization into simulated body fluid and P24 incorporation for enhanced bone formation. In vitro experiments revealed that surface mineralization-modified (SMM) TBC scaffolds demonstrated efficiency for sustained release of P24. The P24/SMM-TBC composite exhibited increased osteogenic activity by cell adhesion rate determination, MTT assay, alkaline phosphatase staining, and calcium nodule staining with alizarin red compared with SMM-TBC and TBC. In vivo studies showed that the P24/SMM-TBC composite scaffold promoted significant bone defect repair, in marked contrast to stand-alone SMM-TBC and TBC, based on the results of radiographic evaluation and histological examination. These findings indicate that SMM-TBC is a good scaffold for the controlled release of P24 and that the P24/SMM-TBC composite could improve the adhesion, proliferation and differentiation of cells and repair bone defects. The double-modified P24/SMM-TBC composite biomaterial shows potential for clinical application in bone tissue engineering. (paper)

Decision tree analysis as a supplementary tool to enhance histomorphological differentiation when distinguishing human from non-human cranial bone in both burnt and unburnt states: A feasibility study.

Science.gov (United States)

Simmons, T; Goodburn, B; Singhrao, S K

2016-01-01

This feasibility study was undertaken to describe and record the histological characteristics of burnt and unburnt cranial bone fragments from human and non-human bones. Reference series of fully mineralized, transverse sections of cranial bone, from all variables and specimen states, were prepared by manual cutting and semi-automated grinding and polishing methods. A photomicrograph catalogue reflecting differences in burnt and unburnt bone from human and non-humans was recorded and qualitative analysis was performed using an established classification system based on primary bone characteristics. The histomorphology associated with human and non-human samples was, for the main part, preserved following burning at high temperature. Clearly, fibro-lamellar complex tissue subtypes, such as plexiform or laminar primary bone, were only present in non-human bones. A decision tree analysis based on histological features provided a definitive identification key for distinguishing human from non-human bone, with an accuracy of 100%. The decision tree for samples where burning was unknown was 96% accurate, and multi-step classification to taxon was possible with 100% accuracy. The results of this feasibility study strongly suggest that histology remains a viable alternative technique if fragments of cranial bone require forensic examination in both burnt and unburnt states. The decision tree analysis may provide an additional but vital tool to enhance data interpretation. Further studies are needed to assess variation in histomorphology taking into account other cranial bones, ontogeny, species and burning conditions. © The Author(s) 2015.

Adaptive noise cancellation

International Nuclear Information System (INIS)

Akram, N.

1999-01-01

In this report we describe the concept of adaptive noise canceling, an alternative method of estimating signals corrupted by additive noise of interference. The method uses 'primary' input containing the corrupted signal and a 'reference' input containing noise correlated in some unknown way with the primary noise, the reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate. Adaptive filtering before subtraction allows the treatment of inputs that are deterministic or stochastic, stationary or time variable. When the reference input is free of signal and certain other conditions are met then noise in the primary input can be essentially eliminated without signal distortion. It is further shown that the adaptive filter also acts as notch filter. Simulated results illustrate the usefulness of the adaptive noise canceling technique. (author)

Histomorphometric quantification of human pathological bones from synchrotron radiation 3D computed microtomography

International Nuclear Information System (INIS)

Nogueira, Liebert P.; Braz, Delson

2011-01-01

Conventional bone histomorphometry is an important method for quantitative evaluation of bone microstructure. X-ray computed microtomography is a noninvasive technique, which can be used to evaluate histomorphometric indices in trabecular bones (BV/TV, BS/BV, Tb.N, Tb.Th, Tb.Sp). In this technique, the output 3D images are used to quantify the whole sample, differently from the conventional one, in which the quantification is performed in 2D slices and extrapolated for 3D case. In this work, histomorphometric quantification using synchrotron 3D X-ray computed microtomography was performed to quantify pathological samples of human bone. Samples of human bones were cut into small blocks (8 mm x 8 mm x 10 mm) with a precision saw and then imaged. The computed microtomographies were obtained at SYRMEP (Synchrotron Radiation for MEdical Physics) beamline, at ELETTRA synchrotron radiation facility (Italy). The obtained 3D images yielded excellent resolution and details of intra-trabecular bone structures, including marrow present inside trabeculae. Histomorphometric quantification was compared to literature as well. (author)

Histomorphometric Parameters of the Growth Plate and Trabecular Bone in Wild-Type and Trefoil Factor Family 3 (Tff3)-Deficient Mice Analyzed by Free and Open-Source Image Processing Software.

Science.gov (United States)

Bijelić, Nikola; Belovari, Tatjana; Stolnik, Dunja; Lovrić, Ivana; Baus Lončar, Mirela

2017-08-01

Trefoil factor family 3 (Tff3) peptide is present during intrauterine endochondral ossification in mice, and its deficiency affects cancellous bone quality in secondary ossification centers of mouse tibiae. The aim of this study was to quantitatively analyze parameters describing the growth plate and primary ossification centers in tibiae of 1-month-old wild-type and Tff3 knock-out mice (n=5 per genotype) by using free and open-source software. Digital photographs of the growth plates and trabecular bone were processed by open-source computer programs GIMP and FIJI. Histomorphometric parameters were calculated using measurements made with FIJI. Tff3 knock-out mice had significantly smaller trabecular number and significantly larger trabecular separation. Trabecular bone volume, trabecular bone surface, and trabecular thickness showed no significant difference between the two groups. Although such histomorphological differences were found in the cancellous bone structure, no significant differences were found in the epiphyseal plate histomorphology. Tff3 peptide probably has an effect on the formation and quality of the cancellous bone in the primary ossification centers, but not through disrupting the epiphyseal plate morphology. This work emphasizes the benefits of using free and open-source programs for morphological studies in life sciences.

Effects of fluoridation of porcine hydroxyapatite on osteoblastic activity of human MG63 cells

International Nuclear Information System (INIS)

Li, Zhipeng; Huang, Baoxin; Mai, Sui; Wu, Xiayi; Zhang, Hanqing; Qiao, Wei; Luo, Xin; Chen, Zhuofan

2015-01-01

Biological hydroxyapatite, derived from animal bones, is the most widely used bone substitute in orthopedic and dental treatments. Fluorine is the trace element involved in bone remodeling and has been confirmed to promote osteogenesis when administered at the appropriate dose. To take advantage of this knowledge, fluorinated porcine hydroxyapatite (FPHA) incorporating increasing levels of fluoride was derived from cancellous porcine bone through straightforward chemical and thermal treatments. Physiochemical characteristics, including crystalline phases, functional groups and dissolution behavior, were investigated on this novel FPHA. Human osteoblast-like MG63 cells were cultured on the FPHA to examine cell attachment, cytoskeleton, proliferation and osteoblastic differentiation for in vitro cellular evaluation. Results suggest that fluoride ions released from the FPHA play a significant role in stimulating osteoblastic activity in vitro, and appropriate level of fluoridation (1.5 to 3.1 atomic percents of fluorine) for the FPHA could be selected with high potential for use as a bone substitute. (paper)

Radiographic Comparison of Bovine Bone Substitute Alone versus Bovine Bone Substitute and Simvastatin for Human Maxillary Sinus Augmentation

Directory of Open Access Journals (Sweden)

Amir Ali Reza Rasouli Ghahroudi

2018-01-01

Full Text Available Objectives: The aim of this study was to compare the efficacy of bovine bone substitute (Compact Bone B. ® alone versus bovine bone substitute and simvastatin for human maxillary sinus augmentation.Materials and Methods: This study was conducted on 16 sinuses in eight patients. Radiographic assessments were done preoperatively (T0, immediately (T1 and at nine months after sinus grafting (T2. Alveolar bone height and density were assessed on cone beam computed tomography (CBCT scans using Planmeca Romexis™ Imaging Software 2.2.Results: The change in alveolar bone height and density between T0, T1 and T2 was significant in both groups. Alveolar bone height (h0, h1, h2 and vertical height of the grafted bone (g1, g2 in three lines (anterior, middle and posterior were not significantly different between groups. The grafted bone height shrinkage (% in the anterior, middle and posterior limits of the augmented area were not significantly different between groups. The existing alveolar and grafted bone density increased significantly in both groups between T1 and T2, except for the existing alveolar bone density in the control group. There were no statistically significant differences between the alveolar bone density values obtained in TI and T2 between groups, except for the existing alveolar bone density at T1.Conclusions: This study did not show any significant positive effect for simvastatin in maxillary sinus augmentation based on radiographic examination.

Simulation for noise cancellation using LMS adaptive filter

Science.gov (United States)

Lee, Jia-Haw; Ooi, Lu-Ean; Ko, Ying-Hao; Teoh, Choe-Yung

2017-06-01

In this paper, the fundamental algorithm of noise cancellation, Least Mean Square (LMS) algorithm is studied and enhanced with adaptive filter. The simulation of the noise cancellation using LMS adaptive filter algorithm is developed. The noise corrupted speech signal and the engine noise signal are used as inputs for LMS adaptive filter algorithm. The filtered signal is compared to the original noise-free speech signal in order to highlight the level of attenuation of the noise signal. The result shows that the noise signal is successfully canceled by the developed adaptive filter. The difference of the noise-free speech signal and filtered signal are calculated and the outcome implies that the filtered signal is approaching the noise-free speech signal upon the adaptive filtering. The frequency range of the successfully canceled noise by the LMS adaptive filter algorithm is determined by performing Fast Fourier Transform (FFT) on the signals. The LMS adaptive filter algorithm shows significant noise cancellation at lower frequency range.

Full-duplex wireless communications systems self-interference cancellation

CERN Document Server

Le-Ngoc, Tho

2017-01-01

This book introduces the development of self-interference (SI)-cancellation techniques for full-duplex wireless communication systems. The authors rely on estimation theory and signal processing to develop SI-cancellation algorithms by generating an estimate of the received SI and subtracting it from the received signal. The authors also cover two new SI-cancellation methods using the new concept of active signal injection (ASI) for full-duplex MIMO-OFDM systems. The ASI approach adds an appropriate cancelling signal to each transmitted signal such that the combined signals from transmit antennas attenuate the SI at the receive antennas. The authors illustrate that the SI-pre-cancelling signal does not affect the data-bearing signal. This book is for researchers and professionals working in wireless communications and engineers willing to understand the challenges of deploying full-duplex and practical solutions to implement a full-duplex system. Advanced-level students in electrical engineering and computer ...

Human Dental Pulp-Derived Cells Produce Bone-Like Tissue and Exhibit Bone Cell-Like Responsiveness to Mechanical Loading

DEFF Research Database (Denmark)

Kraft, David Christian Evar; Melsen, Birte; Bindslev, Dorthe Arenholt

2010-01-01

and characterize cell lines from human 3rd molar dental pulp tissue to determine whether human dental pulp-derived cells (DPCs) are osteogenic and responsive to mechanical loading by pulsating fluid flow (PFF) in vitro. Methods: Human DPCs used for this study were characterized by measuring proliferation....... We also assessed bone formation by DPCs on hydroxyapatite-tricalcium phosphate granules after subcutaneous implantation in mice. Results: We found that DPCs are intrinsically mechanosensitive and, like osteogenic cells, respond to PFF-induced fluid shear stress. Implantation of DPCs resulted...... remodeling in vivo, and therefore provide a promising new tool for regenerative dentistry, for example mineralized tissue engineering to restore bone defects in relation to periodontitis, periimplantatis and orofacial surgery. Experiments in progress have proven that DPCSs are also useful for assessing...

A Framework for Music-Speech Segregation using Music Fingerprinting and Acoustic Echo Cancellation Principle

International Nuclear Information System (INIS)

Hussain, F.; Habib, H. A.; Khan, M. J.

2015-01-01

Background interference creates voice intelligibility issue for listerner. This research work considers background music as interference for communication through smart phone in areas with loud background music. This paper proposes a novel framework for background music segregation from human speech using music fingerprinting and acoustic echo cancellation. Initially, background music is searched in the database by music fingerprinting. Identified background music is registered and segregated using acoustic echo cancellation. Proposed approach generates better quality music speech segregation than existing algorithms. The research work is novel and segregates background music completely in comparison to existing approaches where single instruments are segregated successfully. (author)

Can experimental data in humans verify the finite element-based bone remodeling algorithm?

DEFF Research Database (Denmark)

Wong, C.; Gehrchen, P.M.; Kiaer, T.

2008-01-01

STUDY DESIGN: A finite element analysis-based bone remodeling study in human was conducted in the lumbar spine operated on with pedicle screws. Bone remodeling results were compared to prospective experimental bone mineral content data of patients operated on with pedicle screws. OBJECTIVE......: The validity of 2 bone remodeling algorithms was evaluated by comparing against prospective bone mineral content measurements. Also, the potential stress shielding effect was examined using the 2 bone remodeling algorithms and the experimental bone mineral data. SUMMARY OF BACKGROUND DATA: In previous studies...... operated on with pedicle screws between L4 and L5. The stress shielding effect was also examined. The bone remodeling results were compared with prospective bone mineral content measurements of 4 patients. They were measured after surgery, 3-, 6- and 12-months postoperatively. RESULTS: After 1 year...

Bone modeling and remodeling: potential as therapeutic targets for the treatment of osteoporosis.

Science.gov (United States)

Langdahl, Bente; Ferrari, Serge; Dempster, David W

2016-12-01

The adult skeleton is renewed by remodeling throughout life. Bone remodeling is a process where osteoclasts and osteoblasts work sequentially in the same bone remodeling unit. After the attainment of peak bone mass, bone remodeling is balanced and bone mass is stable for one or two decades until age-related bone loss begins. Age-related bone loss is caused by increases in resorptive activity and reduced bone formation. The relative importance of cortical remodeling increases with age as cancellous bone is lost and remodeling activity in both compartments increases. Bone modeling describes the process whereby bones are shaped or reshaped by the independent action of osteoblast and osteoclasts. The activities of osteoblasts and osteoclasts are not necessarily coupled anatomically or temporally. Bone modeling defines skeletal development and growth but continues throughout life. Modeling-based bone formation contributes to the periosteal expansion, just as remodeling-based resorption is responsible for the medullary expansion seen at the long bones with aging. Existing and upcoming treatments affect remodeling as well as modeling. Teriparatide stimulates bone formation, 70% of which is remodeling based and 20-30% is modeling based. The vast majority of modeling represents overflow from remodeling units rather than de novo modeling. Denosumab inhibits bone remodeling but is permissive for modeling at cortex. Odanacatib inhibits bone resorption by inhibiting cathepsin K activity, whereas modeling-based bone formation is stimulated at periosteal surfaces. Inhibition of sclerostin stimulates bone formation and histomorphometric analysis demonstrated that bone formation is predominantly modeling based. The bone-mass response to some osteoporosis treatments in humans certainly suggests that nonremodeling mechanisms contribute to this response and bone modeling may be such a mechanism. To date, this has only been demonstrated for teriparatide, however, it is clear that

27 CFR 479.87 - Cancellation of stamp.

Science.gov (United States)

2010-04-01

... OTHER FIREARMS Transfer Tax Application and Order for Transfer of Firearm § 479.87 Cancellation of stamp. The method of cancellation of the stamp required by this subpart as prescribed in § 479.67 shall be used. Exemptions Relating to Transfers of Firearms ...

Human Bone Derived Collagen for the Development of an Artificial Corneal Endothelial Graft. In Vivo Results in a Rabbit Model.

Directory of Open Access Journals (Sweden)

Natalia Vázquez

Full Text Available Corneal keratoplasty (penetrating or lamellar using cadaveric human tissue, is nowadays the main treatment for corneal endotelial dysfunctions. However, there is a worldwide shortage of donor corneas available for transplantation and about 53% of the world's population have no access to corneal transplantation. Generating a complete cornea by tissue engineering is still a tough goal, but an endothelial lamellar graft might be an easier task. In this study, we developed a tissue engineered corneal endothelium by culturing human corneal endothelial cells on a human purified type I collagen membrane. Human corneal endothelial cells were cultured from corneal rims after corneal penetrating keratoplasty and type I collagen was isolated from remnant cancellous bone chips. Isolated type I collagen was analyzed by western blot, liquid chromatography -mass spectrometry and quantified using the exponentially modified protein abundance index. Later on, collagen solution was casted at room temperature obtaining an optically transparent and mechanically manageable membrane that supports the growth of human and rabbit corneal endothelial cells which expressed characteristic markers of corneal endothelium: zonula ocluddens-1 and Na+/K+ ATPase. To evaluate the therapeutic efficiency of our artificial endothelial grafts, human purified type I collagen membranes cultured with rabbit corneal endothelial cells were transplanted in New Zealand white rabbits that were kept under a minimal immunosuppression regimen. Transplanted corneas maintained transparency for as long as 6 weeks without obvious edema or immune rejection and maintaining the same endothelial markers that in a healthy cornea. In conclusion, it is possible to develop an artificial human corneal endothelial graft using remnant tissues that are not employed in transplant procedures. This artificial endothelial graft can restore the integrality of corneal endothelium in an experimental model of

Multimodal biometric approach for cancelable face template generation

Science.gov (United States)

Paul, Padma Polash; Gavrilova, Marina

2012-06-01

Due to the rapid growth of biometric technology, template protection becomes crucial to secure integrity of the biometric security system and prevent unauthorized access. Cancelable biometrics is emerging as one of the best solutions to secure the biometric identification and verification system. We present a novel technique for robust cancelable template generation algorithm that takes advantage of the multimodal biometric using feature level fusion. Feature level fusion of different facial features is applied to generate the cancelable template. A proposed algorithm based on the multi-fold random projection and fuzzy communication scheme is used for this purpose. In cancelable template generation, one of the main difficulties is keeping interclass variance of the feature. We have found that interclass variations of the features that are lost during multi fold random projection can be recovered using fusion of different feature subsets and projecting in a new feature domain. Applying the multimodal technique in feature level, we enhance the interclass variability hence improving the performance of the system. We have tested the system for classifier fusion for different feature subset and different cancelable template fusion. Experiments have shown that cancelable template improves the performance of the biometric system compared with the original template.

CERN Library - Scientific journal cancellations

CERN Multimedia

2004-01-01

Due to the constant increase of the subscription costs of scientific journals and the current budget restrictions, the Scientific Information Policy Board has mandated the Working Group for Acquisitions (WGA) together with the Library to propose a list of titles to be cancelled at the end of 2004. As a first step, the WGA has identified the scientific journals listed at the web site below as candidates for cancellation. The choice has been guided by the personal experience of the WGA members, consultation of other expert CERN staff for highly specialized titles, and by criteria such as subscription price, impact factor, and - where available - access statistics for electronic journals. The list also accounts for the fact that many titles are subscribed to in 'packages' such that a cancellation of individual titles would not lead to any cost savings. We invite users to carefully check the list on the Library homepage (http://library.cern.ch/). If you find any title that you consider critically important for y...

Cryogenic 3D printing for producing hierarchical porous and rhBMP-2-loaded Ca-P/PLLA nanocomposite scaffolds for bone tissue engineering.

Science.gov (United States)

Wang, Chong; Zhao, Qilong; Wang, Min

2017-06-07

The performance of bone tissue engineering scaffolds can be assessed through cell responses to scaffolds, including cell attachment, infiltration, morphogenesis, proliferation, differentiation, etc, which are determined or heavily influenced by the composition, structure, mechanical properties, and biological properties (e.g. osteoconductivity and osteoinductivity) of scaffolds. Although some promising 3D printing techniques such as fused deposition modeling and selective laser sintering could be employed to produce biodegradable bone tissue engineering scaffolds with customized shapes and tailored interconnected pores, effective methods for fabricating scaffolds with well-designed hierarchical porous structure (both interconnected macropores and surface micropores) and tunable osteoconductivity/osteoinductivity still need to be developed. In this investigation, a novel cryogenic 3D printing technique was investigated and developed for producing hierarchical porous and recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded calcium phosphate (Ca-P) nanoparticle/poly(L-lactic acid) nanocomposite scaffolds, in which the Ca-P nanoparticle-incorporated scaffold layer and rhBMP-2-encapsulated scaffold layer were deposited alternatingly using different types of emulsions as printing inks. The mechanical properties of the as-printed scaffolds were comparable to those of human cancellous bone. Sustained releases of Ca 2+ ions and rhBMP-2 were achieved and the biological activity of rhBMP-2 was well-preserved. Scaffolds with a desirable hierarchical porous structure and dual delivery of Ca 2+ ions and rhBMP-2 exhibited superior performance in directing the behaviors of human bone marrow-derived mesenchymal stem cells and caused improved cell viability, attachment, proliferation, and osteogenic differentiation, which has suggested their great potential for bone tissue engineering.

MESOLITHIC HUMAN BONES FROM THE UPPER VOLGA BASIN : RADIOCARBON AND TRACE ELEMENTS

NARCIS (Netherlands)

Alexandrovskiy, A. L.; Alexandrovskaya, E. I.; Zhilin, M. I.; van der Plicht, J.

2009-01-01

Human bones from 3 Mesolithic sites in the Upper Volga basin were analyzed for trace elements, and dated by accelerator mass spectrometry (AMS). The radiocarbon dates of the bones correspond to the Mesolithic era. However, some dates differ from those obtained for the enclosing deposits and for the

5 CFR 837.803 - Cancellation of retirement by judicial or administrative authority.

Science.gov (United States)

2010-01-01

... Canceled Retirements § 837.803 Cancellation of retirement by judicial or administrative authority. (a... may only be canceled by the former employing agency in response to a direct and final order of a... requiring cancellation of the annuitant's separation or after the annuitant and the agency agree to cancel...

Aging, human immunodeficiency virus, and bone health

Directory of Open Access Journals (Sweden)

Kim C Mansky

2010-09-01

Full Text Available Kim C ManskyDivision of Orthodontics, Department of Developmental and Surgical Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, USAAbstract: Highly active antiretroviral therapy (HAART has had a profound impact on improving the long-term prognosis for individuals infected with human immunodeficiency virus (HIV. HAART has been available for close to two decades, and now a significant number of patients with access to HAART are over the age of 50 years. Many clinical studies have indicated that HIV infection, as well as components of HAART, can increase the risk in these individuals to a variety of noninfectious complications, including a risk to bone health. There is a significant need for detailed mechanistic analysis of the aging, HIV-infected population regarding the risk of HIV infection and therapy in order to maintain bone health. Insights from basic mechanistic studies will help to shed light on the role of HIV infection and the components of HAART that impact bone health, and will help in identifying preventative countermeasures, particularly for individuals 50 years of age and older.Keywords: osteopenia, osteomalacia, osteoporosis, bisphosphonates, tenofovir, osteoimmunology

Empirical properties of inter-cancellation durations in the Chinese stock market

Directory of Open Access Journals (Sweden)

Gao-Feng eGu

2014-03-01

Full Text Available Order cancellation process plays a crucial role in the dynamics of price formation in order-driven stock markets and is important in the construction and validation of computational finance models. Based on the order flow data of 23 liquid stocks traded on the Shenzhen Stock Exchange in 2003, we investigate the empirical statistical properties of inter-cancellation durations in units of events defined as the waiting times between two consecutive cancellations. The inter-cancellation durations for both buy and sell orders of all the stocks favor a $q$-exponential distribution when the maximum likelihood estimation method is adopted; In contrast, both cancelled buy orders of 9 stocks and cancelled sell orders of 4 stocks prefer Weibull distribution when the nonlinear least-square estimation is used. Applying detrended fluctuation analysis (DFA, centered detrending moving average (CDMA and multifractal detrended fluctuation analysis (MF-DFA methods, we unveil that the inter-cancellation duration time series process long memory and multifractal nature for both buy and sell cancellations of all the stocks. Our findings show that order cancellation processes exhibit long-range correlated bursty behaviors and are thus not Poissonian.

The use of total human bone marrow fraction in a direct three-dimensional expansion approach for bone tissue engineering applications: focus on angiogenesis and osteogenesis.

Science.gov (United States)

Guerrero, Julien; Oliveira, Hugo; Catros, Sylvain; Siadous, Robin; Derkaoui, Sidi-Mohammed; Bareille, Reine; Letourneur, Didier; Amédée, Joëlle

2015-03-01

Current approaches in bone tissue engineering have shown limited success, mostly owing to insufficient vascularization of the construct. A common approach consists of co-culture of endothelial cells and osteoblastic cells. This strategy uses cells from different sources and differentiation states, thus increasing the complexity upstream of a clinical application. The source of reparative cells is paramount for the success of bone tissue engineering applications. In this context, stem cells obtained from human bone marrow hold much promise. Here, we analyzed the potential of human whole bone marrow cells directly expanded in a three-dimensional (3D) polymer matrix and focused on the further characterization of this heterogeneous population and on their ability to promote angiogenesis and osteogenesis, both in vitro and in vivo, in a subcutaneous model. Cellular aggregates were formed within 24 h and over the 12-day culture period expressed endothelial and bone-specific markers and a specific junctional protein. Ectopic implantation of the tissue-engineered constructs revealed osteoid tissue and vessel formation both at the periphery and within the implant. This work sheds light on the potential clinical use of human whole bone marrow for bone regeneration strategies, focusing on a simplified approach to develop a direct 3D culture without two-dimensional isolation or expansion.

Can Spatiotemporal Fluoride (18F?) Uptake be Used to Assess Bone Formation in the Tibia? A Longitudinal Study Using PET/CT

OpenAIRE

Lundblad, Henrik; Karlsson-Thur, Charlotte; Maguire, Gerald Q.; Jonsson, Cathrine; Noz, Marilyn E.; Zeleznik, Michael P.; Weidenhielm, Lars

2017-01-01

Background When a bone is broken for any reason, it is important for the orthopaedic surgeon to know how bone healing is progressing. There has been resurgence in the use of the fluoride (18F?) ion to evaluate various bone conditions. This has been made possible by availability of positron emission tomography (PET)/CT hybrid scanners together with cyclotrons. Absorbed on the bone surface from blood flow, 18F? attaches to the osteoblasts in cancellous bone and acts as a pharmacokinetic agent, ...

Mechanical Vibration Mitigates the Decrease of Bone Quantity and Bone Quality of Leptin Receptor-Deficient Db/Db Mice by Promoting Bone Formation and Inhibiting Bone Resorption.

Science.gov (United States)

Jing, Da; Luo, Erping; Cai, Jing; Tong, Shichao; Zhai, Mingming; Shen, Guanghao; Wang, Xin; Luo, Zhuojing

2016-09-01

Leptin, a major hormonal product of adipocytes, is involved in regulating appetite and energy metabolism. Substantial studies have revealed the anabolic actions of leptin on skeletons and bone cells both in vivo and in vitro. Growing evidence has substantiated that leptin receptor-deficient db/db mice exhibit decreased bone mass and impaired bone microstructure despite several conflicting results previously reported. We herein systematically investigated bone microarchitecture, mechanical strength, bone turnover and its potential molecular mechanisms in db/db mice. More importantly, we also explored an effective approach for increasing bone mass in leptin receptor-deficient animals in an easy and noninvasive manner. Our results show that deterioration of trabecular and cortical bone microarchitecture and decreases of skeletal mechanical strength-including maximum load, yield load, stiffness, energy, tissue-level modulus and hardness-in db/db mice were significantly ameliorated by 12-week, whole-body vibration (WBV) with 0.5 g, 45 Hz via micro-computed tomography (μCT), three-point bending, and nanoindentation examinations. Serum biochemical analysis shows that WBV significantly decreased serum tartrate-resistant acid phosphatase 5b (TRACP5b) and CTx-1 levels and also mitigated the reduction of serum osteocalcin (OCN) in db/db mice. Bone histomorphometric analysis confirmed that decreased bone formation-lower mineral apposition rate, bone formation rate, and osteoblast numbers in cancellous bone-in db/db mice were suppressed by WBV. Real-time PCR assays show that WBV mitigated the reductions of tibial alkaline phosphatase (ALP), OCN, Runt-related transcription factor 2 (RUNX2), type I collagen (COL1), BMP2, Wnt3a, Lrp6, and β-catenin mRNA expression, and prevented the increases of tibial sclerostin (SOST), RANK, RANKL, RANL/osteoprotegerin (OPG) gene levels in db/db mice. Our results show that WBV promoted bone quantity and quality in db/db mice with obvious

3D Architecture of Trabecular Bone in the Pig Mandible and Femur: Inter-Trabecular Angle Distributions.

Science.gov (United States)

Ben-Zvi, Yehonatan; Reznikov, Natalie; Shahar, Ron; Weiner, Steve

2017-09-01

Cancellous bone is an intricate network of interconnected trabeculae, to which analysis of network topology can be applied. The inter-trabecular angle (ITA) analysis - an analysis of network topological parameters and regularity of network-forming nodes, was previously carried out on human proximal femora and showed that trabecular bone follows two main principles: sparsity of the network connectedness (prevalence of nodes with low connectivity in the network) and maximal space spanning (angular offset of connected elements is maximal for their number and approximates the values of geometrically symmetric shapes). These observations suggest that 3D organization of trabecular bone, irrespective of size and shape of individual elements, reflects a tradeoff between minimal metabolic cost of maintenance and maximal network stability under conditions of multidirectional loading. In this study we validate the ITA application using additional 3D structures (cork and 3D-printed metal lattices), analyze the ITA parameters in porcine proximal femora and mandibles and carry out a spatial analysis of the most common node type in the porcine mandibular condyle. The validation shows that the ITA application reliably detects designed or evolved topological parameters. The ITA parameters of porcine trabecular bones are similar to those of human bones. We demonstrate functional adaptation in the pig mandibular condyle by showing that the planar nodes with 3 edges are preferentially aligned in relation to the muscle forces that are applied to the condyle. We conclude that the ITA topological parameters are remarkable conserved, but locally do adapt to applied stresses.

3D Architecture of Trabecular Bone in the Pig Mandible and Femur: Inter-Trabecular Angle Distributions

Directory of Open Access Journals (Sweden)

Yehonatan Ben-Zvi

2017-09-01

Full Text Available Cancellous bone is an intricate network of interconnected trabeculae, to which analysis of network topology can be applied. The inter-trabecular angle (ITA analysis—an analysis of network topological parameters and regularity of network-forming nodes—was previously carried out on human proximal femora and showed that trabecular bone follows two main principles: sparsity of the network connectedness (prevalence of nodes with low connectivity in the network and maximal space spanning (angular offset of connected elements is maximal for their number and approximates the values of geometrically symmetric shapes. These observations suggest that 3D organization of trabecular bone, irrespective of size and shape of individual elements, reflects a tradeoff between minimal metabolic cost of maintenance and maximal network stability under conditions of multidirectional loading. In this study, we validate the ITA application using additional 3D structures (cork and 3D-printed metal lattices, analyze the ITA parameters in porcine proximal femora and mandibles, and carry out a spatial analysis of the most common node type in the porcine mandibular condyle. The validation shows that the ITA application reliably detects designed or evolved topological parameters. The ITA parameters of porcine trabecular bones are similar to those of human bones. We demonstrate functional adaptation in the pig mandibular condyle by showing that the planar nodes with three edges are preferentially aligned in relation to the muscle forces that are applied to the condyle. We conclude that the ITA topological parameters are remarkably conserved, but locally do adapt to applied stresses.

Mechanical properties of the normal human cartilage-bone complex in relation to age

DEFF Research Database (Denmark)

Ding, Ming; Dalstra, M; Linde, F

1998-01-01

OBJECTIVE: This study investigates the age-related variations in the mechanical properties of the normal human tibial cartilage-bone complex and the relationships between cartilage and bone. DESIGN: A novel technique was applied to assess the mechanical properties of the cartilage and bone by mea...... that are of importance for the understanding of the etiology and pathogenesis of degenerative joint diseases, such as arthrosis....

An animal model in sheep for biocompatibility testing of biomaterials in cancellous bones

OpenAIRE

Nuss, Katja MR; Auer, Joerg A; Boos, Alois; Rechenberg, Brigitte von

2006-01-01

Abstract Background The past years have seen the development of many synthetic bone replacements. To test their biocompatibility and ability for osseointegration, osseoinduction and -conduction requires their placement within bone preferably in an animal experiment of a higher species. Methods A suitable experimental animal model in sheep with drill holes of 8 mm diameter and 13 mm depth within the proximal and distal humerus and femur for testing biocompatibility issues is introduced. Result...

5 CFR 894.602 - May I cancel my enrollment at any time?

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false May I cancel my enrollment at any time... Cancellation of Coverage § 894.602 May I cancel my enrollment at any time? No. You may only cancel your enrollment during an open season. Exceptions: You may cancel your dental and/or vision enrollment if you...

Maxillary anterior ridge augmentation with recombinant human bone morphogenetic protein 2.

Science.gov (United States)

Edmunds, Ryan K; Mealey, Brian L; Mills, Michael P; Thoma, Daniel S; Schoolfield, John; Cochran, David L; Mellonig, Jim

2014-01-01

No human studies exist on the use of recombinant human bone morphogenetic protein 2 (rhBMP-2) on an absorbable collagen sponge (ACS) as a sole graft material for lateral ridge augmentation in large ridge defect sites. This series evaluates the treatment outcome of maxillary anterior lateral ridge augmentation with rhBMP-2/ACS. Twenty patients were treated with rhBMP-2/ACS and fixation screws for space maintenance. Cone beam volumetric tomography measurements were used to determine gain in ridge width, and a bone core biopsy was obtained. The mean horizontal ridge gain was 1.2 mm across sites, and every site gained width.

Optimal Reinsertion of Cancelled Train Lines

DEFF Research Database (Denmark)

Groth, Julie Jespersen; Clausen, Jens

2006-01-01

One recovery strategy in case of a major disruption in rail network is to cancel all trains on a specific line of the network. When the disturbance has ended, the cancelled line must be reinserted as soon as possible. In this article we present a mixed integer programming (MIP) model for calculat....... The model finds the optimal solution in an average of 0.5 CPU seconds in each test case....

Introduction to skeletal radiology and bone growth

International Nuclear Information System (INIS)

Rogers, L.F.

1987-01-01

Radiographic examination is the key to the diagnosis of many skeletal abnormalities. It is essential that each bone be examined in its entirety, including the cortex, medullary canal (cancellous bone or spongiosa), and articular ends. The position and alignment of joints are determined. In children, the epiphysis and epiphyseal line or physis must be observed. The adjacent soft tissues are examined. Obliteration of normal soft-tissue lines and the presence of a joint effusion are of particular importance. When disease is present, it is important to determine whether the process is limited to a single bone or joint or whether multiple bones or joints are involved. The distribution of disease is also a consideration. The presence and type of bone destruction and bone production, the appearance of the edges or borders of the lesion, and the presence or absence of cortical expansion and periosteal reaction are also noted. The radiographic findings are then correlated with the clinical history and the age and sex of the patient to arrive at a logical diagnosis. The diagnosis may be firm in some instances; in other cases, a differential diagnosis is offered since the exact diagnosis cannot be determined

Cancelled surgeries and payment by results in the English National Health Service.

Science.gov (United States)

McIntosh, Bryan; Cookson, Graham; Jones, Simon

2012-04-01

To model the frequency of 'last minute' cancellations of planned elective procedures in the English NHS with respect to the patient and provider factors that led to these cancellations. A dataset of 5,288,604 elective patients spell in the English NHS from January 1st, 2007 to December 31st, 2007 was extracted from the Hospital Episode Statistics. A binary dependent variable indicating whether or not a patient had a Health Resource Group coded as S22--'Planned elective procedure not carried out'--was modeled using a probit regression estimated via maximum likelihood including patient, case and hospital level covariates. Longer waiting times and being admitted on a Monday were associated with a greater rate of cancelled procedures. Male patients, patients from lower socio-economic groups and older patients had higher rates of cancelled procedures. There was significant variation in cancellation rates between hospitals; Foundation Trusts and private facilities had the lowest cancellation rates. Further research is needed on why Foundation Trusts exhibit lower cancellation rates. Hospitals with relatively high cancellation rates should be encouraged to tackle this problem. Further evidence is needed on whether hospitals are more likely to cancel operations where the procedure tariff is lower than the S22 tariff as this creates a perverse incentive to cancel. Understanding the underlying causes of why male, older and patients from lower socio-economic groups are more likely to have their operations cancelled is important to inform the appropriate policy response. This research suggests that interventions designed to reduce cancellation rates should be targeted to high-cancellation groups.

[Progesterone Promotes Human Bone Marrow Mesenchymal Stem Cells to Synthesize Fibronectin via ERK Pathway].

Science.gov (United States)

Wu, Zhen-Yong; Chen, Jing-Li; Huang, Shu; Zhang, Hui; Wang, Fang; Wang, Yan; Bi, Xiao-Yun; Guo, Zi-Kuan

2015-12-01

To investigate whether the progesterone can promote fibronection (FN) synthesis by human bone marrow mesenchymal stem cells (MSCs) and to explore the potential underlying mechanism. The human bone marrow MSCs were cultured in a serum-free medium with progesterone for 72 hours, the MTT test was performed to observe the proliferation status and adhension ability of the treated cells. Western blot was used to detect the content of FN in MSDs with GAPDH as the internal reference, the phosphorylation of ERK1/2, as well as the FN content in MSC treated by PD98059, a specific inhibitor of ERK1/2. The progesterone at a range of certain doses not effect on the proliferation of human bone marrow MSCs. Progesterone (25 µg/L) treatment enhanced the FN expression and adherent ability of marrow MSCs. Progesterone could induce prompt phosphorylation of ERK 1/2 and its promoting effects on FN synthesis was reversed by PD98059. The progesterone can promote FN synthesis by human bone marrow MSCs via ERK 1/2 pathway, and it might be used to culture MSCs in serum-free medium.

Bone marrow aspiration and biopsy. Technique and considerations

Directory of Open Access Journals (Sweden)

R.A. Trejo-Ayala

2015-10-01

Full Text Available Bone marrow aspiration and bone marrow biopsy are invasive procedures in which good technical skill is crucial to obtain samples suitable for processing and diagnostic interpretation. The type and calibre of the needle is one of the main variables of the technique, and is selected on the basis of the age, gender and body mass of the patient. This article provides a practical, step-by-step guide to the technique for both procedures. It also discusses existing techniques for reducing the pain associated with the procedure, an essential aspect for the patient that if poorly handled, can force cancellation of the procedure.

Suppression of autophagy in osteocytes does not modify the adverse effects of glucocorticoids on cortical bone.

Science.gov (United States)

Piemontese, Marilina; Onal, Melda; Xiong, Jinhu; Wang, Yiying; Almeida, Maria; Thostenson, Jeff D; Weinstein, Robert S; Manolagas, Stavros C; O'Brien, Charles A

2015-06-01

Glucocorticoid excess decreases bone mass and strength in part by acting directly on osteoblasts and osteocytes, but the mechanisms remain unclear. Macroautophagy (herein referred to as autophagy) is a lysosome-based recycling pathway that promotes the turnover of intracellular components and can promote cell function and survival under stressful conditions. Recent studies have shown that glucocorticoids stimulate autophagy in osteocytes, suggesting that autophagy may oppose the negative actions of glucocorticoids on this cell type. To address this possibility, we compared the impact of prednisolone administration on the skeletons of adult mice in which autophagy was suppressed in osteocytes, via deletion of Atg7 with a Dmp1-Cre transgene, to their control littermates. In control mice, prednisolone increased autophagic flux in osteocyte-enriched bone as measured by LC3 conversion, but this change did not occur in the mice lacking Atg7 in osteocytes. Nonetheless, prednisolone reduced femoral cortical thickness, increased cortical porosity, and reduced bone strength to similar extents in mice with and without autophagy in osteocytes. Prednisolone also suppressed osteoblast number and bone formation in the cancellous bone of control mice. As shown previously, Atg7 deletion in osteocytes reduced osteoblast number and bone formation in cancellous bone, but these parameters were not further reduced by prednisolone administration. In cortical bone, prednisolone elevated osteoclast number to a similar extent in both genotypes. Taken together, these results demonstrate that although glucocorticoids stimulate autophagy in osteocytes, suppression of autophagy in this cell type does not worsen the negative impact of glucocorticoids on the skeleton. Published by Elsevier Inc.