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Sample records for adolescent cancellous bone

  1. Three-dimensional microarchitecture of adolescent cancellous bone.

    PubMed

    Ding, Ming; Danielsen, Carl Christian; Hvid, Ivan; Overgaard, Søren

    2012-11-01

    This study investigated microarchitectural, mechanical, collagen and mineral properties of normal adolescent cancellous bone, and compared them with adult and aging cancellous bone, to obtain more insight into the subchondral bone adaptations during development and growth. Twenty-three human proximal tibiae were harvested and divided into 3 groups according to their ages: adolescence (9 to 17 years, n=6), young adult (18 to 24 years, n=9), and adult (25 to 30 years, n=8). Twelve cubic cancellous bone samples with dimensions of 8×8×8 mm(3) were produced from each tibia, 6 from each medial and lateral condyle. These samples were micro-CT scanned (vivaCT 40, Scanco Medical AG, Switzerland) resulting in cubic voxel sizes of 10.5*10.5*10.5 μm(3). Microarchitectural properties were calculated. The samples were then tested in compression followed by collagen and mineral determination. Interestingly, the adolescent cancellous bone had similar bone volume fraction (BV/TV), structure type (plate, rod or mixtures), and connectivity (3-D trabecular networks) as the adult cancellous bone. The adolescent cancellous bone had significantly lower bone surface density (bone surface per total volume of specimen) but higher collagen concentration (collagen weight per dry weight of specimen) than the adult cancellous bone; and significant greater trabecular separation (mean distance between trabeculae), significant lower trabecular number (number of trabeculae per volume), tissue density (dry weight per volume of bone matrix excluding marrow space) and mineral concentration (ash weight per dry weight of specimen) than the young adult and adult cancellous bones. Despite these differences, ultimate stress and failure energy were not significantly different among the three groups, only the Young's modulus in anterior-posterior direction was significantly lower in adolescence. Apparent density appears to be the single best predictor of mechanical properties. In conclusion, adolescent

  2. Cancellous bone repair using bovine trabecular bone matrix particulates.

    PubMed

    Mushipe, M T; Revell, P A; Shelton, J C

    2002-01-01

    At 5 and 15 weeks post-surgery, biomechanical and histological analyses of cancellous bone defects filled with the bovine trabecular bone matrix (BBM) and hydroxyapatite (Hap) particulates of dimensions 106-150 microm were investigated. It was observed that at 5 weeks post-surgery the stiffness properties of the BBM filled defects were significantly higher than those observed in the Hap filled defects (p < 0.01) but comparable to those recorded in intact cancellous bone from the same anatomical position. Histologically, no significant differences were observed in the percentage of new bone contact with the particles. The biomechanical properties of the Hap filled defects mirrored those in intact cancellous bone only at 15 weeks post-surgery. BBM particles thus appeared to accelerate the early healing of osteotomies. It is therefore suggested that particles of this bioceramic be the subject of intense research for more usage in both periodontal osseous defects and orthopaedic fractures.

  3. Hardness, an indicator of the mechanical competence of cancellous bone.

    PubMed

    Hodgskinson, R; Currey, J D; Evans, G P

    1989-01-01

    Hardness and calcium content in compact bone are strongly related. Variation in Young's modulus is produced mainly by variations in mineralisation. Therefore, there should be a relationship between hardness and Young's modulus. We demonstrate this. The calcium content of cancellous bone and adjacent compact bone in several species shows little difference, the cancellous bone having approximately 10% less calcium. The hardness of cancellous bone in Bos is approximately 12% less than that of adjacent compact bone, and the calcium is approximately 2% less. These lines of evidence make it unlikely that the Young modulus of cancellous bone material is much different from that of compact bone. Similar evidence suggests that the yield stress of cancellous bone is similar to that of adjacent compact bone.

  4. Cadmium content of human cancellous bone

    SciTech Connect

    Knuuttila, M.; Lappalainen, R.; Olkkonen, H.; Lammi, S.; Albava, E.M.

    1982-09-01

    The cadmium content of human cancellous bone was related to age, sex, bone loss, physical properties, and elemental composition. Bone specimens from the anterior iliac crest were collected from 88 cadavers with a normal mineral status, and from 50 cadavers which had bone loss from chronic diseases and immobilization. The element concentrations were analyzed using atomic absorption spectrophotometry. Bone fluoride levels were determined with the ion specific electrode, the mineral density with the gamma ray attenuation method, and the compressive strength with a strain transducer. The data were analyzed using multiple linear regression analysis. The mean cadmium content of 0.22 +/- 0.16 ..mu..g/g dry weight (+/- SD) in the samples did not change with age and its content was slightly greater in males than in females. Furthermore, no statistically significant relationship was found in cadmium content to bone loss changes or to the calcium content of bone. The cadmium content had a high statistically significant positive correlation with the strontium and nickel content.

  5. Cadmium content of human cancellous bone.

    PubMed

    Knuuttila, M; Lappalainen, R; Olkkonen, H; Lammi, S; Alhava, E M

    1982-01-01

    The cadmium content of human cancellous bone was related to age, sex, bone loss, physical properties, and elemental composition. Bone specimens from the anterior iliac crest were collected from 889 cadavers with a normal mineral status, and from 50 cadavers which had bone loss from chronic diseases and immobilization. The element concentrations were analyzed using atomic absorption spectrophotometry. Bone fluoride levels ere determined with the ion specific electrode, the mineral density with the gamma ray attenuation method, and the compressive strength with a strain transducer. The data were analyzed using multiple linear regression analysis. The mean cadmium content of 0.22 +/- 9.16 micrograms/g dry weight (+/- SD) in the samples did not change with age and its content was slightly greater in males than in females. Furthermore, no statistically significant relation was found in cadmium content to bone loss changes or to the calcium content of bone. The cadmium content had a high statistically significant positive correlation with the strontium and nickel content. PMID:7138079

  6. Transversely isotropic elasticity imaging of cancellous bone.

    PubMed

    Shore, Spencer W; Barbone, Paul E; Oberai, Assad A; Morgan, Elise F

    2011-06-01

    To measure spatial variations in mechanical properties of biological materials, prior studies have typically performed mechanical tests on excised specimens of tissue. Less invasive measurements, however, are preferable in many applications, such as patient-specific modeling, disease diagnosis, and tracking of age- or damage-related degradation of mechanical properties. Elasticity imaging (elastography) is a nondestructive imaging method in which the distribution of elastic properties throughout a specimen can be reconstructed from measured strain or displacement fields. To date, most work in elasticity imaging has concerned incompressible, isotropic materials. This study presents an extension of elasticity imaging to three-dimensional, compressible, transversely isotropic materials. The formulation and solution of an inverse problem for an anisotropic tissue subjected to a combination of quasi-static loads is described, and an optimization and regularization strategy that indirectly obtains the solution to the inverse problem is presented. Several applications of transversely isotropic elasticity imaging to cancellous bone from the human vertebra are then considered. The feasibility of using isotropic elasticity imaging to obtain meaningful reconstructions of the distribution of material properties for vertebral cancellous bone from experiment is established. However, using simulation, it is shown that an isotropic reconstruction is not appropriate for anisotropic materials. It is further shown that the transversely isotropic method identifies a solution that predicts the measured displacements, reveals regions of low stiffness, and recovers all five elastic parameters with approximately 10% error. The recovery of a given elastic parameter is found to require the presence of its corresponding strain (e.g., a deformation that generates ɛ₁₂ is necessary to reconstruct C₁₂₁₂), and the application of regularization is shown to improve accuracy. Finally

  7. Effect of thermodisinfection on mechanic parameters of cancellous bone.

    PubMed

    Fölsch, Christian; Kellotat, Andreas; Rickert, Markus; Ishaque, Bernd; Ahmed, Gafar; Pruss, Axel; Jahnke, Alexander

    2016-09-01

    Revision surgery of joint replacements is increasing and raises the demand for allograft bone since restoration of bone stock is crucial for longevity of implants. Proceedings of bone grafts influence the biological and mechanic properties differently. This study examines the effect of thermodisinfection on mechanic properties of cancellous bone. Bone cylinders from both femoral heads with length 45 mm were taken from twenty-three 6-8 months-old piglets, thermodisinfected at 82.5 °C according to bone bank guidelines and control remained native. The specimens were stored at -20 °C immediately and were put into 21 °C Ringer's solution for 3 h before testing. Shear and pressure modulus were tested since three point bending force was examined until destruction. Statistical analysis was done with non-parametric Wilcoxon, t test and SPSS since p < 0.05 was significant. Shear modulus was significantly reduced by thermodisinfection to 1.02 ± 0.31 GPa from 1.28 ± 0.68 GPa for unprocessed cancellous bone (p = 0.029) since thermodisinfection reduced pressure modulus not significantly from 6.30 ± 4.72 GPa for native specimens to 4.97 ± 2.23 GPa and maximum bending force was 270.03 ± 116.68 N for native and 228.80 ± 70.49 N for thermodisinfected cancellous bone. Shear and pressure modulus were reduced by thermodisinfection around 20 % and maximum bending force was impaired by about 15 % compared with native cancellous bone since only the reduction of shear modulus reached significance. The results suggest that thermodisinfection similarly affects different mechanic properties of cancellous bone and the reduction of mechanic properties should not relevantly impair clinical use of thermodisinfected cancellous bone. PMID:27344440

  8. Postoperative irradiation of fresh autogenic cancellous bone grafts

    SciTech Connect

    Schwartz, H.C.; Leake, D.L.; Kagan, A.R.; Snow, H.; Pizzoferrato, A.

    1986-01-01

    Discontinuity defects were created in the mandibles of dogs and then reconstructed immediately with fresh autogenic cancellous bone grafts and Dacron-urethane prostheses. The grafts were irradiated to a total dose of 5000 rads after waiting intervals of between 3 and 12 weeks. Nonirradiated grafts served as controls. The grafts were evaluated clinically, radiographically, and histologically. There was complete incorporation of all grafts, regardless of the interval between surgery and radiotherapy. There were no soft-tissue complications. The controls were distinguishable from the irradiated grafts only by the presence of hematopoietic bone marrow. Fibrofatty marrow was observed in the irradiated grafts. Theoretical support for this technique is found in the biology of cancellous bone grafting and the pathology of radiation injury. In view of the difficulties associated with mandibular bone grafting in preoperatively irradiated patients, a new method of reconstructing selected cancer patients who require both mandibular resection and radiotherapy is suggested.

  9. Inter-trabecular bone formation: a specific mechanism for healing of cancellous bone

    PubMed Central

    Sandberg, Olof H; Aspenberg, Per

    2016-01-01

    Background and purpose Studies of fracture healing have mainly dealt with shaft fractures, both experimentally and clinically. In contrast, most patients have metaphyseal fractures. There is an increasing awareness that metaphyseal fractures heal partly through mechanisms specific to cancellous bone. Several new models for the study of cancellous bone healing have recently been presented. This review summarizes our current knowledge of cancellous fracture healing. Methods We performed a review of the literature after doing a systematic literature search. Results Cancellous bone appears to heal mainly via direct, membranous bone formation that occurs freely in the marrow, probably mostly arising from local stem cells. This mechanism appears to be specific for cancellous bone, and could be named inter-trabecular bone formation. This kind of bone formation is spatially restricted and does not extend more than a few mm outside the injured region. Usually no cartilage is seen, although external callus and cartilage formation can be induced in meta­physeal fractures by mechanical instability. Inter-trabecular bone formation seems to be less sensitive to anti-inflammatory treatment than shaft fractures. Interpretation The unique characteristics of inter-trabecular bone formation in metaphyseal fractures can lead to differences from shaft healing regarding the effects of age, loading, or drug treatment. This casts doubt on generalizations about fracture healing based solely on shaft fracture models. PMID:27357416

  10. Predicting Bone Mechanical Properties of Cancellous Bone from DXA, MRI, and Fractal Dimensional Measurements

    NASA Technical Reports Server (NTRS)

    Harrigan, Timothy P.; Ambrose, Catherine G.; Hogan, Harry A.; Shackleford, Linda; Webster, Laurie; LeBlanc, Adrian; Lin, Chen; Evans, Harlan

    1997-01-01

    This project was aimed at making predictions of bone mechanical properties from non-invasive DXA and MRI measurements. Given the bone mechanical properties, stress calculations can be made to compare normal bone stresses to the stresses developed in exercise countermeasures against bone loss during space flight. These calculations in turn will be used to assess whether mechanical factors can explain bone loss in space. In this study we assessed the use of T2(sup *) MRI imaging, DXA, and fractal dimensional analysis to predict strength and stiffness in cancellous bone.

  11. Microhardness of human cancellous bone tissue in progressive hip osteoarthritis.

    PubMed

    Tomanik, Magdalena; Nikodem, Anna; Filipiak, Jarosław

    2016-12-01

    Bone tissue is a biological system in which the dynamic processes of, among others, bone formation or internal reconstruction will determine the spatial structure of the tissue and its mechanical properties. The appearance of a factor disturbing the balance between biological processes, e.g. a disease, will cause changes in the spatial structure of bones, thus affecting its mechanical properties. One of the bone diseases most common in an increasingly ageing population is osteoarthritis, also referred to as degenerative joint disease. It is estimated that in 2050 about 1300 million people will show symptoms of OA. The appearance of a pathological stimulus disturbs the balance of the processes of degradation and synthesis of articular cartilage, chondrocytes and the extracellular matrix, and the subchondral bone layer. As osteoarthritis progresses, study of the epiphysis reveals increasingly widespread changes of the articular surface and the internal structure of bone tissue. In this paper, the authors point out the differences in the mechanical properties of cancellous bone tissue forming the proximal epiphysis of the femoral bone during the progressive stages of OA. In order to determine microproperties of bone trabeculae, specimens from different stages of the disease (N=9) were subjected to microindentation testing, which made it possible to determine the material properties of bone tissue, such as microhardness HV and Young׳s modulus E. In addition, mechanical tests were supplemented with Raman spectroscopy, which determine the degree of bone mineralization, and measurements of structural properties based on analysis using microCT. The conducted tests were used to establish both quantitative and quantitative description of changes in the structural and mechanical properties connected with reorganization of trabeculae making up the bone in the various stages of osteoarthritis. The proposed description will supplement existing knowledge in the literature about

  12. Microhardness of human cancellous bone tissue in progressive hip osteoarthritis.

    PubMed

    Tomanik, Magdalena; Nikodem, Anna; Filipiak, Jarosław

    2016-12-01

    Bone tissue is a biological system in which the dynamic processes of, among others, bone formation or internal reconstruction will determine the spatial structure of the tissue and its mechanical properties. The appearance of a factor disturbing the balance between biological processes, e.g. a disease, will cause changes in the spatial structure of bones, thus affecting its mechanical properties. One of the bone diseases most common in an increasingly ageing population is osteoarthritis, also referred to as degenerative joint disease. It is estimated that in 2050 about 1300 million people will show symptoms of OA. The appearance of a pathological stimulus disturbs the balance of the processes of degradation and synthesis of articular cartilage, chondrocytes and the extracellular matrix, and the subchondral bone layer. As osteoarthritis progresses, study of the epiphysis reveals increasingly widespread changes of the articular surface and the internal structure of bone tissue. In this paper, the authors point out the differences in the mechanical properties of cancellous bone tissue forming the proximal epiphysis of the femoral bone during the progressive stages of OA. In order to determine microproperties of bone trabeculae, specimens from different stages of the disease (N=9) were subjected to microindentation testing, which made it possible to determine the material properties of bone tissue, such as microhardness HV and Young׳s modulus E. In addition, mechanical tests were supplemented with Raman spectroscopy, which determine the degree of bone mineralization, and measurements of structural properties based on analysis using microCT. The conducted tests were used to establish both quantitative and quantitative description of changes in the structural and mechanical properties connected with reorganization of trabeculae making up the bone in the various stages of osteoarthritis. The proposed description will supplement existing knowledge in the literature about

  13. Cancellous Screws Are Biomechanically Superior to Cortical Screws in Metaphyseal Bone.

    PubMed

    Wang, Tim; Boone, Christopher; Behn, Anthony W; Ledesma, Justin B; Bishop, Julius A

    2016-09-01

    Cancellous screws are designed to optimize fixation in metaphyseal bone environments; however, certain clinical situations may require the substitution of cortical screws for use in cancellous bone, such as anatomic constraints, fragment size, or available instrumentation. This study compares the biomechanical properties of commercially available cortical and cancellous screw designs in a synthetic model representing various bone densities. Commercially available, fully threaded, 4.0-mm outer-diameter cortical and cancellous screws were tested in terms of pullout strength and maximum insertion torque in standard-density and osteoporotic cancellous bone models. Pullout strength and maximum insertion torque were both found to be greater for cancellous screws than cortical screws in all synthetic densities tested. The magnitude of difference in pullout strength between cortical and cancellous screws increased with decreasing synthetic bone density. Screw displacement prior to failure and total energy absorbed during pullout strength testing were also significantly greater for cancellous screws in osteoporotic models. Stiffness was greater for cancellous screws in standard and osteoporotic models. Cancellous screws have biomechanical advantages over cortical screws when used in metaphyseal bone, implying the ability to both achieve greater compression and resist displacement at the screw-plate interface. Surgeons should preferentially use cancellous over cortical screws in metaphyseal environments where cortical bone is insufficient for fixation. [Orthopedics.2016; 39(5):e828-e832.].

  14. Reward Improves Cancellation and Restraint Inhibition Across Childhood and Adolescence

    PubMed Central

    Sinopoli, Katia J.; Schachar, Russell; Dennis, Maureen

    2011-01-01

    Inhibitory control allows for the regulation of thought and action, and interacts with motivational variables, such as reward, to modify behavior adaptively as environments change. We examined the effects of reward on two distinct forms of inhibitory control, cancellation and restraint. Typically developing children and adolescents completed two versions of the stop signal task (cancellation and restraint) under three reward conditions (neutral, low reward, and high reward), where rewards were earned for successful inhibitory control. Rewards improved both cancellation and restraint inhibition, with similar effects of reward on each form of inhibitory control. Rewards did not alter the speed of response execution in either task, suggesting that rewards specifically altered inhibition processes without influencing processes related to response execution. Adolescents were faster and less variable than children when executing and inhibiting their responses. There were similar developmental effects of reward on the speed of inhibitory control, but group differences were found in terms of accuracy of inhibition in the restraint task. These results clarify how reward modulates two different forms of regulatory behavior in children and adolescents. PMID:21744952

  15. Ultrasonic backscatter from cancellous bone: the apparent backscatter transfer function.

    PubMed

    Hoffmeister, Brent K; Mcpherson, Joseph A; Smathers, Morgan R; Spinolo, P Luke; Sellers, Mark E

    2015-12-01

    Ultrasonic backscatter techniques are being developed to detect changes in cancellous bone caused by osteoporosis. Many techniques are based on measurements of the apparent backscatter transfer function (ABTF), which represents the backscattered power from bone corrected for the frequency response of the measurement system. The ABTF is determined from a portion of the backscatter signal selected by an analysis gate of width τw delayed by an amount τd from the start of the signal. The goal of this study was to characterize the ABTF for a wide range of gate delays (1 μs ≤ τd ≤ 6 μs) and gate widths (1 μs ≤ τw ≤ 6 μs). Measurements were performed on 29 specimens of human cancellous bone in the frequency range 1.5 to 6.0 MHz using a broadband 5-MHz transducer. The ABTF was found to be an approximately linear function of frequency for most choices of τd and τw. Changes in τd and τw caused the frequency-averaged ABTF [quantified by apparent integrated backscatter (AIB)] and the frequency dependence of the ABTF [quantified by frequency slope of apparent backscatter (FSAB)] to change by as much as 24.6 dB and 6.7 dB/MHz, respectively. τd strongly influenced the measured values of AIB and FSAB and the correlation of AIB with bone density (-0.95 ≤ R ≤ +0.68). The correlation of FSAB with bone density was influenced less strongly by τd (-0.97 ≤ R ≤ -0.87). τw had a weaker influence than τd on the measured values of AIB and FSAB and the correlation of these parameters with bone density.

  16. Cancellous bone homograft storage with aluminium-polyethylene bags.

    PubMed

    Meana, A; Martinez, R; Cañal, P; Arriaga, M J; Román, F San; Llames, S; Orós, C; Moreno, A; Fernandez, C

    2006-01-01

    In order to transport and cryopreserve human tissues, it is essential to have an easy-to-use recipient where tissues can be kept in sterile conditions. Here we show the results obtained by using Macopharma's tissue freezing bags, an aluminium-polyethylene multilayer bag, in our tissue bank of the Centro Comunitario de Sangre y Tejidos de Asturias. Five hundred and twenty-seven cancellous bone homografts were obtained from hospitals located 120 km around our Bank. The homografts were submitted to bacteriological controls and sent to our bank in these bags. They were stored at -70 degrees C and sent in dry ice to about 50 hospitals, where the tissue was bacteriologically controlled and grafted. Furthermore, the behaviour of these bags at -140 degrees C (vapour nitrogen) or -196 degrees C (liquid nitrogen) was tested. Our results indicate that Macopharma aluminium-polyethylene bags are suitable for the transporting and cryopreserving of cancellous bone homografts. These bags could also be used for keeping tissues in nitrogen containers.

  17. A method for isolating high quality RNA from mouse cortical and cancellous bone.

    PubMed

    Kelly, Natalie H; Schimenti, John C; Patrick Ross, F; van der Meulen, Marjolein C H

    2014-11-01

    The high incidence of fragility fractures in cortico-cancellous bone locations, plus the fact that individual skeletal sites exhibit different responsiveness to load and disease, emphasizes the need to document separately gene expression in cortical and cancellous bone. A further confounding factor is marrow contamination since its high cellularity may effect gene expression measurements. We isolated RNA from cortical and cancellous bone of intact mouse tibiae, and also after marrow removal by flushing or centrifugation. RNA isolated from cancellous bone by each method was sufficient for gene expression analysis. Centrifugation removed contaminating cells more efficiently than flushing, as indexed by histology and decreased expression of Icam4, a highly expressed erythroid gene. In contrast, centrifuged cortical bone had 12- and 13- fold higher expression of the bone-related genes Col1a1 and Bglap, while levels in marrow-free cancellous bone were 30- and 31-fold higher when compared to bone where marrow was left intact. Furthermore, cortical bone had higher expression of Col1a1 and Bglap than cancellous bone. Thus, RNA isolated by this novel approach can reveal site-specific changes in gene expression in cortical and cancellous bone sites. PMID:25073031

  18. Mechanical Properties of a Single Cancellous Bone Trabeculae Taken from Bovine Femur

    NASA Astrophysics Data System (ADS)

    Enoki, Shinichi; Sato, Mitsuhiro; Tanaka, Kazuto; Katayama, Tsutao

    The increase of patients with osteoporosis is becoming a social problem, thus it is an urgent issue to find its prevention and treatment methods. Since cancellous bone is metabolically more active than cortical bone, cancellous bone is often used for diagnosis of osteoporosis and has received much attention within the study of bone. Bone is a hierarchically structured material and its mechanical properties vary at different structural levels, therefore it is important to break down the mechanical testing of bone according to the various levels within bone material. Mechanical properties of cancellous bone is said to be depended on quantities and orientation of trabecular bone. It is supposed that mechanical properties of trabecular bone are constant without depending on any structural arrangement and parts. However, such assumption has not been established in studies of trabecular bone. Furthermore test results have a large margin of error caused by insufficient shape assessment. In this study, three point bending tests of single cancellous bone trabeculae extracted from bovine femur were conducted to evaluate the effects of directions to the femur major axis direction on the mechanical properties. X-ray μCT was used to obtain shape of trabecular bone specimens. Furthermore compression tests of cancellous bone specimens, which were extracted in 10mm cubic geometry, were conducted for evaluation of directional properties.There were small difference in the elastic modulus of the trabecular bones which were extracted in parallel and in perpendicular to the major axis of femur. Considering from the results that the cancellous bone specimens, which were extracted in 10mm cubic geometry, have different elastic properties depending on the tested directions; the bone structure has larger influence than bone material property on the mechanical properties of cancellous bone.

  19. Finite element prediction of fatigue damage growth in cancellous bone.

    PubMed

    Hambli, Ridha; Frikha, Sana; Toumi, Hechmi; Tavares, João Manuel R S

    2016-01-01

    Cyclic stresses applied to bones generate fatigue damage that affects the bone stiffness and its elastic modulus. This paper proposes a finite element model for the prediction of fatigue damage accumulation and failure in cancellous bone at continuum scale. The model is based on continuum damage mechanics and incorporates crack closure effects in compression. The propagation of the cracks is completely simulated throughout the damaged area. In this case, the stiffness of the broken element is reduced by 98% to ensure no stress-carrying capacities of completely damaged elements. Once a crack is initiated, the propagation direction is simulated by the propagation of the broken elements of the mesh. The proposed model suggests that damage evolves over a real physical time variable (cycles). In order to reduce the computation time, the integration of the damage growth rate is based on the cycle blocks approach. In this approach, the real number of cycles is reduced (divided) into equivalent blocks of cycles. Damage accumulation is computed over the cycle blocks and then extrapolated over the corresponding real cycles. The results show a clear difference between local tensile and compressive stresses on damage accumulation. Incorporating stiffness reduction also produces a redistribution of the peak stresses in the damaged region, which results in a delay in damage fracture.

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

    PubMed

    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.

  1. Isolation, cultivation and characterisation of pigeon osteoblasts seeded on xenogeneic demineralised cancellous bone scaffold for bone grafting.

    PubMed

    Harvanová, Denisa; Hornák, Slavomír; Amrichová, Judita; Spaková, Tímea; Mikes, Jaromír; Plsíková, Jana; Ledecký, Valent; Rosocha, Ján

    2014-09-01

    Avian osteoblasts have been isolated particularly from chicken embryo, but data about other functional tissue sources of adult avian osteoblast precursors are missing. The method of preparation of pigeon osteoblasts is described in this study. We demonstrate that pigeon cancellous bone derived osteoblasts have particular proliferative capacity in vitro in comparison to mammalian species and developed endogenous ALP. Calcium deposits formation in vitro was confirmed by alizarin red staining. Only a few studies have attempted to investigate bone grafting and treatment of bone loss in birds. Lack of autologous bone grafts in birds has prompted investigation into the use of avian xenografts for bone augmentation. Here we present a method of xenografting of ostrich demineralised cancellous bone scaffold seeded with allogeneic adult pigeon osteoblasts. Ostrich demineralised cancellous bone scaffold supported proliferation of pigeon osteoblasts during two weeks of co - cultivation in vitro. Scanning electron microscopy demonstrated homogeneous adult pigeon osteoblasts attachment and distribution on the surface of xenogeneic ostrich demineralised cancellous bone. Our preliminary in vitro results indicate that demineralised cancellous bone from ostrich tibia could provide an effective biological support for growth and proliferation of allogeneic osteoblasts derived from cancellous bone of pigeons. PMID:24915787

  2. Isolation, cultivation and characterisation of pigeon osteoblasts seeded on xenogeneic demineralised cancellous bone scaffold for bone grafting.

    PubMed

    Harvanová, Denisa; Hornák, Slavomír; Amrichová, Judita; Spaková, Tímea; Mikes, Jaromír; Plsíková, Jana; Ledecký, Valent; Rosocha, Ján

    2014-09-01

    Avian osteoblasts have been isolated particularly from chicken embryo, but data about other functional tissue sources of adult avian osteoblast precursors are missing. The method of preparation of pigeon osteoblasts is described in this study. We demonstrate that pigeon cancellous bone derived osteoblasts have particular proliferative capacity in vitro in comparison to mammalian species and developed endogenous ALP. Calcium deposits formation in vitro was confirmed by alizarin red staining. Only a few studies have attempted to investigate bone grafting and treatment of bone loss in birds. Lack of autologous bone grafts in birds has prompted investigation into the use of avian xenografts for bone augmentation. Here we present a method of xenografting of ostrich demineralised cancellous bone scaffold seeded with allogeneic adult pigeon osteoblasts. Ostrich demineralised cancellous bone scaffold supported proliferation of pigeon osteoblasts during two weeks of co - cultivation in vitro. Scanning electron microscopy demonstrated homogeneous adult pigeon osteoblasts attachment and distribution on the surface of xenogeneic ostrich demineralised cancellous bone. Our preliminary in vitro results indicate that demineralised cancellous bone from ostrich tibia could provide an effective biological support for growth and proliferation of allogeneic osteoblasts derived from cancellous bone of pigeons.

  3. An investigation into the feasibility of implementing fractal paradigms to simulate cancellous bone structure.

    PubMed

    Haire, T J; Ganney, P S; Langton, C M

    2001-01-01

    Cancellous bone consists of a framework of solid trabeculae interspersed with bone marrow. The structure of the bone tissue framework is highly convoluted and complex, being fractal and statistically self-similar over a limited range of magnifications. To date, the structure of natural cancellous bone tissue has been defined using 2D and 3D imaging, with no facility to modify and control the structure. The potential of four computer-generated paradigms has been reviewed based upon knowledge of other fractal structures and chaotic systems, namely Diffusion Limited Aggregation (DLA), Percolation and Epidemics, Cellular Automata, and a regular Grid with randomly relocated nodes. The resulting structures were compared for their ability to create realistic structures of cancellous bone rather than reflecting growth and form processes. Although the creation of realistic computer-generated cancellous bone structures is difficult, it should not be impossible. Future work considering the combination of fractal and chaotic paradigms is underway. PMID:11328644

  4. The effects of PTH, loading and surgical insult on cancellous bone at the bone-implant interface in the rabbit

    PubMed Central

    Fahlgren, Anna; Yang, Xu; Ciani, Cesare; Ryan, James A.; Kelly, Natalie; Ko, Frank C.; van der Meulen, Marjolein C.H.; Bostrom, Mathias P.G.

    2014-01-01

    Enhancing the quantity and quality of cancellous bone with anabolic pharmacologic agents may lead to more successful outcomes of non-cemented joint replacements. Using a novel rabbit model of cancellous bone loading, we examined two specific questions regarding bone formation at the bone-implant interface: (1) does the administration of intermittent PTH, a potent anabolic agent, and mechanical loading individually and combined enhance the peri-implant cancellous bone volume fraction; and, (2) does surgical trauma enhance the anabolic effect of PTH on peri-implant bone volume fraction. In this model, PTH enhanced peri-implant bone volume fraction by 30% in loaded bone, while mechanical loading alone increased bone volume fraction modestly (+10%). Combined mechanical loading and PTH treatment had no synergistic effect on any cancellous parameters. However, a strong combined effect was found in bone volume fraction with combined surgery and PTH treatment (+34%) compared to intact control limbs. Adaptive changes in the cancellous bone tissue included increased ultimate stress and enhanced remodeling activity. The number of proliferative osteoblasts increased as did their expression of pro-collagen 1 and PTH receptor 1, and the number of TRAP positive osteoclasts also increased. In summary, both loading and intermittent PTH treatment enhanced peri-implant bone volume, and surgery and PTH treatment had a strong combined effect. This finding is of clinical importance since enhancing early osseointegration in the post-surgical period has numerous potential benefits. PMID:22613252

  5. Decreased cortical and increased cancellous bone in two children with primary hyperparathyroidism.

    PubMed

    Boechat, M I; Westra, S J; Van Dop, C; Kaufman, F; Gilsanz, V; Roe, T F

    1996-01-01

    The basis for this study is two children with primary hyperparathyroidism (PHPT) who radiographically manifested both marked subperiosteal resorption and prominent osteosclerosis. We hypothesize that the parathyroid hormone (PTH) elevation not only increased osteoclastic resorption of cortical bone but also simultaneously enhanced cancellous bone formation, giving rise to osteosclerosis. In this report, we describe the changes in trabecular and cortical bone density, as measured by quantitative computed tomography (QCT), in these two young patients with severe PHPT, before and after removal of a parathyroid adenoma. Before surgery, the radiographic findings of subperiosteal resorption and osteosclerosis were associated with low cortical and high cancellous bone density values in both children. Within 1 week of surgery, both cortical and cancellous bone density values increased and serum concentrations of calcium and, to a lesser degree, phosphorus decreased due to the "hungry bone syndrome." Twelve weeks after parathyroidectomy, QCT bone density values and skeletal radiographs were normal in both patients. The findings suggest that in patients with severe PHPT, the catabolic effect of PTH on cortical bone may be associated with a simultaneous anabolic effect on cancellous bone, and PTH may cause a significant redistribution of bone mineral from cortical to cancellous bone. PMID:8544781

  6. The effect of screw pullout rate on screw purchase in synthetic cancellous bone.

    PubMed

    Zdero, Rad; Schemitsch, Emil H

    2009-02-01

    Clinically, orthopaedic fracture fixation constructs are mounted using screws inserted into cancellous bone, while biomechanical studies are increasingly using commercially available synthetic bones. The goal of this study was to examine the effect of screw pullout rate on cancellous bone screw purchase strength in synthetic cancellous bone. Sixty synthetic cancellous bone cubes (40x40x40 mm(3)) each had one orthopaedic cancellous bone screw (major diameter=6.5 mm) inserted to a depth of 30 mm. Screws were extracted to obtain outcome measures of failure force, failure shear stress, failure energy, failure displacement, resistance force, and removal energy. The ten test groups (n=6 cubes per group) had screws extracted at pullout rates of 1 mmmin, 2.5 mmmin, 5 mmmin, 7.5 mmmin, 10 mmmin, 20 mmmin, 30 mmmin, 40 mmmin, 50 mmmin, and 60 mmmin. The aggregate average results for failure force, failure stress, failure energy, failure displacement, resistance force, and postfailure removal energy for combined pullout rates were, respectively, 984.8+/-63.9 N, 3.5+/-0.2 MPa, 298.3+/-41.7 J, 0.53+/-0.08 mm, 453.8+/-19.6 N, and 5420.1+/-489.7 J. Most statistical differences (40 of 47) involved either the 5 mmmin or the 60 mmmin rates being compared to other rates. Failure force, failure stress, and resistance force increased and were highly linearly correlated with pullout rate (R(2)=0.78, 0.76, and 0.74, respectively). Failure energy, failure displacement, and removal energy were relatively unchanged over the pullout range tested, yielding low correlation coefficients (R(2)<0.05). Failure force, failure stress, and resistance force were affected by bone screw pullout rate in synthetic cancellous bone, while failure energy, failure displacement, and removal energy remained unchanged. This is the first study to perform an extensive investigation of cancellous bone screw pullout rate in synthetic cancellous bone.

  7. Spatial relationships between bone formation and mechanical stress within cancellous bone.

    PubMed

    Cresswell, E N; Goff, M G; Nguyen, T M; Lee, W X; Hernandez, C J

    2016-01-25

    Bone adapts to mechanical stimuli. While in vivo mechanical loading has been shown to increase the density of cancellous bone, theory suggests that the relationship between tissue stress/strain and subsequent bone formation occurs at the scale of individual trabeculae. Here we examine bone formation one week following mechanical stimulus. Three bouts of cyclic loading (300 cycles/day on 3 consecutive days) were applied to caudal vertebrae of female rats (n=7). Bone formation was determined using three-dimensional images of fluorescent markers of bone formation (0.7×0.7×5.0μm(3)) and local tissue stress/strain was determined using high-resolution finite element models. Three days of mechanical stimuli resulted in an increase in mineralizing surface (loaded: 17.68±2.17%; control: 9.05±3.20%; mean±SD) and an increase in the volume of bone formed (loaded: 7.09±1.97%; control: 1.44±0.50%). The number of bone formation sites was greater in loaded animals (650.71±118.54) than pinned not loaded controls (310.71±91.55), a difference that was explained by the number of formation sites at regions with large local tissue strain energy density (SED). In addition, the probability of observing bone formation was greater at locations of the microstructure experiencing greater SED, but did not exceed 32%, consistent with prior work. Our findings demonstrate that bone formation in the week following a short term mechanical stimulus occurs near regions of bone tissue experiencing high tissue SED, although the ability of finite element models to predict the locations of bone formation remains modest and further improvements may require accounting for additional factors such as osteocyte distribution or fluid flow.

  8. Penetration of piperacillin-tazobactam into cancellous and cortical bone tissues.

    PubMed Central

    Incavo, S J; Ronchetti, P J; Choi, J H; Wu, H; Kinzig, M; Sörgel, F

    1994-01-01

    The penetration characteristics of piperacillin-tazobactam into cortical and cancellous bone tissues were investigated in 10 patients undergoing total hip replacement. The concentration ratios of piperacillin/tazobactam were 9.4 +/- 1.8 in cancellous bone tissue and 8.0 +/- 2.2 in cortical bone tissue, which were close to the 8:1 ratio of drugs administered. The mean ratios of drug concentrations in bone and plasma for cancellous and cortical tissue were 23 and 18%, respectively, for piperacillin and 26 and 22%, respectively, for tazobactam. The concentrations of tazobactam achieved are sufficient to exert anti-beta-lactamase activity and supportive of clinical trials involving bone and joint infections, including those caused by beta-lactamase-producing pathogens. PMID:8031071

  9. Effect of medullary cavity in cancellous bone on two-wave phenomenon

    NASA Astrophysics Data System (ADS)

    Hachiken, Takuma; Nakanishi, Shoko; Matsukawa, Mami

    2016-07-01

    Osteoporotic patients have a larger medullary cavity in their cancellous bone than healthy people. In this study, the effect of the medullary cavity on the two-wave phenomenon was experimentally investigated using a cancellous bone model and a radius bone model. In the cancellous bone model, with the increase in hole (medullary cavity) diameter, the amplitudes of the fast waves became smaller, whereas the amplitudes of the slow waves became larger. In the radius bone model, the fast wave overlapped with the circumferential wave. The slow wave became larger with increasing hole diameter. The analysis of the slow wave thus seems to be useful for the in vivo diagnosis of the degree of osteoporosis.

  10. Oxidative stress and gamma radiation-induced cancellous bone loss with musculoskeletal disuse

    PubMed Central

    Kondo, Hisataka; Yumoto, Kenji; Alwood, Joshua S.; Mojarrab, Rose; Wang, Angela; Almeida, Eduardo A. C.; Searby, Nancy D.; Limoli, Charles L.

    2010-01-01

    Exposure of astronauts in space to radiation during weightlessness may contribute to subsequent bone loss. Gamma irradiation of postpubertal mice rapidly increases the number of bone-resorbing osteoclasts and causes bone loss in cancellous tissue; similar changes occur in skeletal diseases associated with oxidative stress. Therefore, we hypothesized that increased oxidative stress mediates radiation-induced bone loss and that musculoskeletal disuse changes the sensitivity of cancellous tissue to radiation exposure. Musculoskeletal disuse by hindlimb unloading (1 or 2 wk) or total body gamma irradiation (1 or 2 Gy of 137Cs) of 4-mo-old, male C57BL/6 mice each decreased cancellous bone volume fraction in the proximal tibiae and lumbar vertebrae. The extent of radiation-induced acute cancellous bone loss in tibiae and lumbar vertebrae was similar in normally loaded and hindlimb-unloaded mice. Similarly, osteoclast surface in the tibiae increased 46% as a result of irradiation, 47% as a result of hindlimb unloading, and 64% as a result of irradiation + hindlimb unloading compared with normally loaded mice. Irradiation, but not hindlimb unloading, reduced viability and increased apoptosis of marrow cells and caused oxidative damage to lipids within mineralized tissue. Irradiation also stimulated generation of reactive oxygen species in marrow cells. Furthermore, injection of α-lipoic acid, an antioxidant, mitigated the acute bone loss caused by irradiation. Together, these results showed that disuse and gamma irradiation, alone or in combination, caused a similar degree of acute cancellous bone loss and shared a common cellular mechanism of increased bone resorption. Furthermore, irradiation, but not disuse, may increase the number of osteoclasts and the extent of acute bone loss via increased reactive oxygen species production and ensuing oxidative damage, implying different molecular mechanisms. The finding that α-lipoic acid protected cancellous tissue from the

  11. Reproducibility of techniques using Archimedes' principle in measuring cancellous bone volume.

    PubMed

    Zou, L; Bloebaum, R D; Bachus, K N

    1997-01-01

    Researchers have been interested in developing techniques to accurately and reproducibly measure the volume fraction of cancellous bone. Historically bone researchers have used Archimedes' principle with water to measure the volume fraction of cancellous bone. Preliminary results in our lab suggested that the calibrated water technique did not provide reproducible results. Because of this difficulty, it was decided to compare the conventional water method to a water with surfactant and a helium method using a micropycnometer. The water/surfactant and the helium methods were attempts to improve the fluid penetration into the small voids present in the cancellous bone structure. In order to compare the reproducibility of the new methods with the conventional water method, 16 cancellous bone specimens were obtained from femoral condyles of human and greyhound dog femora. The volume fraction measurements on each specimen were repeated three times with all three techniques. The results showed that the helium displacement method was more than an order of magnitudes more reproducible than the two other water methods (p < 0.05). Statistical analysis also showed that the conventional water method produced the lowest reproducibility (p < 0.05). The data from this study indicate that the helium displacement technique is a very useful, rapid and reproducible tool for quantitatively characterizing anisotropic porous tissue structures such as cancellous bone.

  12. Reproducibility of techniques using Archimedes' principle in measuring cancellous bone volume.

    PubMed

    Zou, L; Bloebaum, R D; Bachus, K N

    1997-01-01

    Researchers have been interested in developing techniques to accurately and reproducibly measure the volume fraction of cancellous bone. Historically bone researchers have used Archimedes' principle with water to measure the volume fraction of cancellous bone. Preliminary results in our lab suggested that the calibrated water technique did not provide reproducible results. Because of this difficulty, it was decided to compare the conventional water method to a water with surfactant and a helium method using a micropycnometer. The water/surfactant and the helium methods were attempts to improve the fluid penetration into the small voids present in the cancellous bone structure. In order to compare the reproducibility of the new methods with the conventional water method, 16 cancellous bone specimens were obtained from femoral condyles of human and greyhound dog femora. The volume fraction measurements on each specimen were repeated three times with all three techniques. The results showed that the helium displacement method was more than an order of magnitudes more reproducible than the two other water methods (p < 0.05). Statistical analysis also showed that the conventional water method produced the lowest reproducibility (p < 0.05). The data from this study indicate that the helium displacement technique is a very useful, rapid and reproducible tool for quantitatively characterizing anisotropic porous tissue structures such as cancellous bone. PMID:9140874

  13. Design of functionally graded dental implant in the presence of cancellous bone.

    PubMed

    Hedia, H S

    2005-10-01

    In a previous work by the author [Hedia HS, Mahmoud NA. Biomed Mater Eng 2004;14(2):133--143], a functionally graded material (FGM) dental implant was designed without cancellous bone in the model. In this investigation, the effect of the presence of cancellous bone as a thin layer around the dental implant was investigated. It is well known that the main inorganic component of natural bone is hydroxyapatite (HAP) and that the main organic component is collagen (Col). HAP implants are not bioabsorbable, and because induction of bone into and around the artificially made HAP is not always satisfactory, loosening or breakage of HAP implants might occur after implantation in the clinical application. The development of a new material that is bioabsorbable and that has osteo-conductive activity is needed. Therefore, the aim of the current investigation was to design an implant, in the presence of cancellous bone as a thin layer around it, from FGM. In this study, a novel biomaterial, Col/HAP, as a FGM, was developed using the finite element and optimization techniques that are available in the ANSYS package. These materials have a self-organized character similar to that of natural bone. The investigations have shown that the maximum stress in the cortical bone and cancellous bone for the Col/HAP functionally graded implant has been reduced by about 40% and 19%, respectively, compared with currently used titanium dental implants.

  14. Pharmacokinetics of cefuroxime in porcine cortical and cancellous bone determined by microdialysis.

    PubMed

    Tøttrup, Mikkel; Hardlei, Tore Forsingdal; Bendtsen, Michael; Bue, Mats; Brock, Birgitte; Fuursted, Kurt; Søballe, Kjeld; Birke-Sørensen, Hanne

    2014-06-01

    Traditionally, the pharmacokinetics of antimicrobials in bone have been investigated using bone biopsy specimens, but this approach suffers from considerable methodological limitations. Consequently, new methods are needed. The objectives of this study were to assess the feasibility of microdialysis (MD) for measuring cefuroxime in bone and to obtain pharmacokinetic profiles for the same drug in porcine cortical and cancellous bone. The measurements were conducted in bone wax sealed and unsealed drill holes in cortical bone and in drill holes in cancellous bone and in subcutaneous tissue. As a reference, the free and total plasma concentrations were also measured. The animals received a bolus of 1,500 mg cefuroxime over 30 min. No significant differences were found between the key pharmacokinetic parameters for sealed and unsealed drill holes in cortical bone. The mean ± standard error of the mean area under the concentration-time curve (AUC) values from 0 to 5 h were 6,013 ± 1,339, 3,222 ± 1086, 2,232 ± 635, and 952 ± 290 min · μg/ml for free plasma, subcutaneous tissue, cancellous bone, and cortical bone, respectively (P < 0.01, analysis of variance). The AUC for cortical bone was also significantly different from that for cancellous bone (P = 0.04). This heterogeneous tissue distribution was also reflected in other key pharmacokinetic parameters. This study validates MD as a suitable method for measuring cefuroxime in bone. Cefuroxime penetration was impaired for all tissues, and bone may not be considered one distinct compartment.

  15. Greater Bone Formation Induction Occurred in Aged than Young Cancellous Bone Sites

    NASA Technical Reports Server (NTRS)

    Ke, H. Z.; Jee, W. S. S.; Ito, H.; Setterberg, R. B.; Li, M.; Lin, B. Y.; Liang, X. G.; Ma, Y. F.

    1993-01-01

    We have determined the differences in the effects of continual prostaglandin E(sub 2) (PGE(sub 2) treatment in aged (non-growing) and young (growing) cancellous bone sites in 7-month-old Sprague-Dawley rats. The sites involved are the aged distal tibial metaphysis (DTM) with a closed epiphysis and the young proximal tibial metaphysis (PTM) with a slow growing, open epiphysis. The study involved rats treated with 0, 1, 3 or 6 mg PGE(sub 2)/kg/d for 60, 120 and 180 days. Static and dynamic histomorphometry of percent trabecular area, and tissue-referent bone formation rate (BFR/TV) were determined in both DTM and PTM. In pretreatment controls, the secondary spongiosa of the two metaphyses contain the same amount of cancellous bone (11% in DTM vs. 13% in PTM), but markedly less bone formation in DTM (0.6%/y in DTM vs. 41.5%/y in PTM). After 60 days of 6 mg PGE(sub 2)/kg/d treatment, %Tb.Ar was increased 607% in DTM and 199% in PTM, BFR/TV was increased to nearly 14 fold in DTM and only 5 fold in PTM. These results indicated the aged metaphysis of the DTM was much more responsive to PGE(sub 2) treatment than young, growing metaphysis of the PTM. The results of 120 and 180 days treatment did not significantly differ from 60 days treatment in both sites, indicating that the effect of continuous daily PGE2 treatment were in equilibrium after 60 days. We concluded that aged metaphysis was much more responsive to PGE(sub 2) treatment than young growing metaphysis.

  16. Greater Bone Fomation Induction Occurred in Aged Than Young Cancellous Bone Sites

    NASA Technical Reports Server (NTRS)

    Ke, H. Z.; Jee, Webster S. S.; Ito, H.; Setterberg, R. B.; Li, M.; Lin, B. Y.; Liang, X. G.; Ma, Y.F.

    1993-01-01

    We have determined the differences in the effects of continual prostaglandin E2 (PGE2) treatment in aged (non-growing) and young (growing) cancellous bone sites in 7 month-old Sprague-Dawley rats. The sites involved are the aged Distal Tibial Metaphysis (DTM) with a closed epiphysis and the young Proximal Tibial Metaphysis (PTM) with a slow growing, open epiphysis. The study involved rats treated with 0, 1, 3 or 6 mg PGE2/kg/d for 60, 120 and 180 days. Static and dynamic histomorphometty of percent trabecular area, and tissue-referent bone formation rate (BFR/TV) were determined in both DTM and PTM. In pretreatment controls, the secondary spongiosa of the two metaphyses contain the same amount of cancellous bone (11% in DTM vs. 13% in PTM), but markedly less bone formation in DTM (0.6%/y in DTM vs. 41.5%/y in PTM). After 60 days of 6 mg PGE2/kg/d treatment, %Tb.Ar was increased 607% in DTM and 199% in PTM, BFR/TV was increased to nearly 14 fold in DTM and only 5 fold in PTM. These results indicated the aged metaphysis of the DTM was much more responsive to PGE2 treatment than young, growing metaphysis of the PTM. The results of 120 and 180 days treatment did not significantly differ from 60 days treatment in both sites, indicating that the effect of continuous daily PGE2 treatment were in equilibrium after 60 days. We concluded that aged metaphysis was much more responsive to PGE2 treatment than young growing metaphysis.

  17. Specimen size effect in the volumetric shrinkage of cancellous bone measured at two levels of dehydration.

    PubMed

    Lievers, W Brent; Lee, Victoria; Arsenault, Simon M; Waldman, Stephen D; Pilkey, A Keith

    2007-01-01

    Water is commonly removed from bone to study its effect on mechanical behaviour; however, dehydration also alters the bone structure. To make matters worse, measuring structural changes in cancellous bone is complicated by a number of factors. Therefore, the goals of this study were to address these issues by (1) comparing Archimedes' method and a helium pycnometer as methods for measuring cancellous bone volume; (2) measuring the apparent dimensional and volumetric tissue shrinkage of cancellous bone at two levels of dehydration; and, (3) identifying whether a size effect exists in cancellous bone shrinkage. Cylindrical specimens (3, 5 and 8.3 mm diameters) of cancellous bone were taken from the distal bovine femur. The apparent dimensions of each cylindrical specimen were measured in a fully hydrated state (HYD), after drying at room temperature (AIR), and after oven drying at 105 degrees C (OVEN). Tissue volume measurements for those three hydration states were obtained using both a helium pycnometer and Archimedes' method. Aluminium foams, which mimic the cancellous structure, were used as controls. The results suggest that the helium pycnometer and Archimedes' method yield identical results in the HYD and AIR states, but that Archimedes' method under-predicts the nominal OVEN volume by incorporating the collagen-apatite porosity. A distinct size effect on volumetric shrinkage is observed (p<0.025) using the pycnometer in both AIR and OVEN states. Apparent dimensional shrinkage (2% and 7%) at the two dehydration levels is much smaller than the measured volumetric tissue shrinkage (16% and 29%), which results in a reduced dehydrated bone volume fraction.

  18. Estrogen modulates the mRNA levels for cancellous bone protein of ovariectomized rats.

    PubMed

    Salih, M A; Liu, C C; Arjmandi, B H; Kalu, D N

    1993-12-01

    This study was undertaken to examine the effects of ovariectomy and 17 beta-estradiol (E2) on the gene expression of type 1 collagen, osteocalcin and the protooncogen, c-myc, in cancellous bone. Female Sprague-Dawley rats, aged 95 days, were divided into 4 groups. Group 1 was sham operated and Groups 2-4 were ovariectomized. Groups 3 and 4 received daily injections of 160 ng and 1600 ng E2/kg body weight, respectively. Groups 1 and 2 received the solvent vehicle. All animals were sacrificed after 14 days. The femurs were dissected out and cancellous bone scraped from the distal metaphysis. RNA was isolated from the cancellous bone, immobilized on filters or size-fractionated by agarose gel electrophoresis and adsorbed on filters which were then hybridized with specific cDNA probes. Ovariectomy resulted in a significant increase in the mRNAs of type 1 collagen, osteocalcin and c-myc. The increase was suppressed in animals that received 17 beta-estradiol injections. In addition, ovariectomy caused the expected decrease in cancellous bone in the proximal tibia and increased osteoclast and osteoblast numbers. The ovariectomy-induced changes were prevented by 17 beta-estradiol administration. These findings suggest that the lack of ovarian hormones shortly after ovariectomy up-regulates and estrogen administration down-regulates the expression of important cancellous bone matrix proteins as well as the protooncogen, c-myc.

  19. Prostaglandin E2 Adds Bone to a Cancellous Bone Site with a Closed Growth Plate and Low Bone Turnover in Ovariectomized Rats

    NASA Technical Reports Server (NTRS)

    Ma, Y. F.; Ke, H. Z.; Jee, W. S. S.

    1994-01-01

    The objects of this study were to determine the responses of a cancellous bone site with a closed growth plate (the distal tibial metaphysis, DTM) to ovariectomy (OVX) and OVX plus a prostaglandin E2 (PGE2) treatment, and compare the site's response to previous findings reported for another site (the proximal tibial metaphysis, PTM). Thirty-five 3-month old female Sprague-Dawley rats were divided into five groups: basal, sham-OVX, and OVX+0, +1, or +6 mg PGE2/kg/d injected subcutaneously for 3 months and given double fluorescent labels before sacrifice. Cancellous bone histomorphometric analyses were performed on 20-micron-thick undecalcified DTM sections. Similar to the PTM, the DTM showed age-related decreases in bone formation and increases in bone resorption, but it differed in that at 3 months post-OVX; there was neither bone loss nor changes in formation endpoints. Giving 1 mg PGE2/kg/d to OVX rats prevented most age-related changes and maintained the bone formation histomorphometry near basal levels. Treating OVX rats with 6 mg PGE2/kg/d prevented age-related bone changes, added extra bone, and improved microanatomical structure by stimulating bone formation without altering bone resorption. Furthermore, after PGE2 administration, the DTM, a cancellous bone site with a closed growth plate, inereased bone formation more than did the cancellous bone in the PTM.

  20. Prostaglandin E2 Adds Bone to a Cancellous Bone Site with a Closed Growth Plate and Low Bone Turnover in Ovariectomized Rats

    NASA Technical Reports Server (NTRS)

    Ma, Y. F.; Ke, H. Z.; Jee, W. S. S.

    1994-01-01

    The objects of this study were to determine the responses of a cancellous bone site with a closed growth plate, (the distal tibial metaphysis (DTM), to ovariectomy (OVX) and OVX plus a prostaglandin E(2) treatment, and compare the site's response to previous findings reported for another site, the proximal tibial metaphysis (PTM). Thirty five 3-month old female Sprague-Dawley rats were divided into five groups; basal, sham OVX, and OVX+0, +1, or +6 mg PGE(2)/kg/d injected subcutaneously for 3 months and given double fluorescent labels before sacrifice. Cancellous bone histomorphometric analyses were performed on 20 micrometer thick undecalcified DTM sections. Similar to the PTM, the DTM showed age-related decreases in bone formation and increases in bone resorption, but it differed in that at 3 months POST OVX there was neither bone loss nor changes in formation endpoints. Giving 1 mg PGE(2)/kg/d to OVX rats prevented most age-related changes and maintained the bone formation histomorphometry near basal levels. Treating OVX rats with 6 mg PGE(2)/kd/d prevented age-related bone changes, added extra bone, and improved microanatomical structure by stimulating bone formation, without altering bone resportion. Futhermore, After PGE(2) admimnistration, the DTM, a cancellous bone site with a closed growth plate, increased bone formation more than did the cancellous bone in the PTM.

  1. Anabolic Responses of an Adult Cancellous Bone Site to Prostaglandin E2 in the Rat

    NASA Technical Reports Server (NTRS)

    Ito, Hiroshi; Ke, Hua Zhu; Jee, Webster S. S.; Sakou, Takashi

    1993-01-01

    The objects of this study were to determine: (1) the response of a non-growing cancellous bone site to daily prostaglandin E2 (PGE2) administration; and (2) the differences in the effects of daily PGE2, administration in growing (proximal tibial metaphysis, PTM) and non-growing cancellous bone sites (distal tibial metaphysis, DTM). Seven-month-old male Sprague-Dawley rats were given daily subcutaneous injections of 0, 1, 3 and 6 mg PGE2/kg per day for 60, 120 and 180 days. The static and dynamic histomorphometric analyses were performed on double-fluorescent labeled undecalcified distal tibial metaphyses (DTM). No age-related changes were found in static and dynamic histomorphometry of DTM cancellous bone between 7 and 13 months of age. The DTM of 7-month-old (basal controls) rats consisted of a 24.5 +/- 7.61%-metaphyseal cancellous bone mass, and a thick trabeculae (92 +/- 12 micro-m). It also had a very low tissue-base bone formation rate (3.0 +/- 7.31%/year). Exogenous PGE2 administration produced the following transient changes in a dose-response manner between zero and 60 days: (1) increased trabecular bone mass and improved architecture (increased trabecular bone area, width and number, and decreased trabecular separation); (2) increased trabecular interconnections: (3) increased bone formation parameters; and (4) decreased eroded perimeter. A new steady state with more cancellous bone mass and higher bone turnover was observed from day 60 onward, The elevated bone mass induced by the first 60 days of PGE2 treatment was maintained by another 60 and 120 days with continuous daily PGE2 treatment. When these findings were compared to those previously reported for the PTM, we found that the DTM was much more responsive to PGE2 treatment than the PTM. Percent trabecular bone area and tissue based bone formation rate increased significantly more in DTM as compared to PTM after the 60 days of 6 mg PGE2 treatment. These observations indicate that a non

  2. Orthogonal cutting of cancellous bone with application to the harvesting of bone autograft.

    PubMed

    Malak, Sharif F F; Anderson, Iain A

    2008-07-01

    Autogenous bone graft harvesting results in cell death within the graft and trauma at the donor site. The latter can be mitigated by using minimally invasive tools and techniques, while cell morbidity may be reduced by improving cutter design and cutting parameters. We have performed orthogonal cutting experiments on bovine cancellous bone samples, to gain a basic understanding of the cutting mechanism and to determine design guidelines for tooling. Measurements were performed at cutting speeds from 11.2 to 5000 mm/min, with tool rake angles of 23 degrees, 45 degrees and 60 degrees, and depths of cut in the range of 0.1-3.0 mm. Horizontal and vertical cutting forces were measured, and the chip formation process video recorded. Continuous chip formation was observed for rake angles of 45 degrees and 60 degrees , and depths of cut greater than 0.8 mm. Chip formation for depths of cut greater than 1.0 mm was accompanied by bone marrow extruding out of the free surfaces and away from the rake face. Specific cutting energies decreased with increasing rake angle, increasing depth of cut and increasing cutting speed. Our orthogonal cutting experiments showed that a rake angle of 60 degrees and a depth of cut of 1mm, will avoid excessive fragmentation, keep specific cutting energy low and promote bone marrow extrusion, which may be beneficial for cell survival. We demonstrate how drill bit clearance angle and feed rate can be calculated facilitating a 1mm depth of cut.

  3. Cortical and cancellous bone in the human femoral neck: evaluation of an interactive image analysis system.

    PubMed

    Bell, K L; Garrahan, N; Kneissel, M; Loveridge, N; Grau, E; Stanton, M; Reeve, J

    1996-11-01

    An interactive image analysis package was developed to examine whole cross-sections from the femoral neck. The package quantifies cortical width (Ct.Wi), cortical porosity (Ct.Po), and proportions of cortical, cancellous bone as a percentage of bone plus marrow area. Segmental analysis was used to quantify circumferential variations in bone distribution within the femoral cross-section. To evaluate reproducibility of data four independent operators analyzed previously prepared femoral neck sections from a 2000 BC population. Differences in total and circumferential distributions of cortical and cancellous bone with respect to gender and age of samples were demonstrated. Reproducibility was assessed using coefficients of variation (CV). Analysis of sections using a variable magnification, giving largest possible image size, rather than a set magnification reduced variation between operators for all measurements. Use of a calculated threshold significantly decreased variation between operators for the proportions of cortical and cancellous bone (p < or = 0.026). Dividing the image into 8 rather than 16 segments also improved reproducibility. There was little agreement between operators in the determination of cortical porosity. The mean CV for the other quantitative indices such as cortical width and proportions of cortical and cancellous bone ranged from 4.87% to 13.52%. The genders showed similar patterns in circumferential distribution of bone. Cortical width was significantly greater in the inferior region compared to the other areas, whereas percent cortical bone was lowest at the superior region. The center of mass (COM) for the younger age group was located anteriorly, whereas in the older samples the COM was located posteriorly of the center of area (p = 0.041). Basic data relating to cortical and cancellous bone of acceptable reproducibility in comparison with current standards in iliac histomorphometry can now be provided at modest cost in operator time and

  4. Ultrasonic characterization of human cancellous bone using the Biot theory: inverse problem.

    PubMed

    Sebaa, N; Fellah, Z E A; Fellah, M; Ogam, E; Wirgin, A; Mitri, F G; Depollier, C; Lauriks, W

    2006-10-01

    This paper concerns the ultrasonic characterization of human cancellous bone samples by solving the inverse problem using experimental transmitted signals. The ultrasonic propagation in cancellous bone is modeled using the Biot theory modified by the Johnson et al. model for viscous exchange between fluid and structure. The sensitivity of the Young modulus and the Poisson ratio of the skeletal frame is studied showing their effect on the fast and slow wave forms. The inverse problem is solved numerically by the least squares method. Five parameters are inverted: the porosity, tortuosity, viscous characteristic length, Young modulus, and Poisson ratio of the skeletal frame. The minimization of the discrepancy between experiment and theory is made in the time domain. The inverse problem is shown to be well posed, and its solution to be unique. Experimental results for slow and fast waves transmitted through human cancellous bone samples are given and compared with theoretical predictions.

  5. The non-linear relationship between BUA and porosity in cancellous bone

    NASA Astrophysics Data System (ADS)

    Hodgskinson, R.; Njeh, C. F.; Whitehead, M. A.; Langton, C. M.

    1996-11-01

    There is growing interest in assessing the clinical value of ultrasound in the prediction and management of osteoporosis. However, the mechanism of ultrasound propagation in cancellous bone is not well understood. The Biot theory is one approach to modelling the interaction of sound waves with cancellous structure, and porosity is one of its input parameters. In this paper we report the relationship between broadband ultrasonic attenuation (BUA) corrected for specimen thickness (nBUA) and porosity in a porous Perspex cancellous bone mimic, a stereolithography cancellous bone mimic and in natural human and bovine tissue. nBUA and porosity have a non-linear parabolic relationship. The maximum nBUA value occurs at approximately 30% porosity in the Perspex mimic, approximately 70% in the stereolithography mimic and approximately 75% in natural cancellous bone. We discuss the effect of structure on the form of the nBUA - porosity relationship.

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

    PubMed

    Lee, Kang Il; 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 degrees , 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.

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

    PubMed

    Giesen, E B W; Ding, M; Dalstra, M; van Eijden, T M G J

    2004-03-01

    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 of the mandibular condyles of edentate subjects (n = 25) was compared with that of dentate subjects (n = 24) by means of micro-computed tomography and by the application of Archimedes' principle. Stiffness and strength were determined by destructive mechanical testing. Compared with dentate subjects, it appeared that, in edentate subjects, the bone was less dense and the trabecular structure was less plate-like. The regression models of stiffness and strength built from bone volume fraction and the trabecular orientation relative to the axis of the specimen were similar for both dentate and edentate subjects. This indicates that, under reduced mechanical load, the fundamental relationship between bone morphology and mechanical properties does not change. PMID:14981130

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

    PubMed Central

    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

  9. Hindlimb unloading has a greater effect on cortical compared with cancellous bone in mature female rats

    NASA Technical Reports Server (NTRS)

    Allen, Matthew R.; Bloomfield, Susan A.

    2003-01-01

    This study was designed to determine the effects of 28 days of hindlimb unloading (HU) on the mature female rat skeleton. In vivo proximal tibia bone mineral density and geometry of HU and cage control (CC) rats were measured with peripheral quantitative computed tomography (pQCT) on days 0 and 28. Postmortem pQCT, histomorphometry, and mechanical testing were performed on tibiae and femora. After 28 days, HU animals had significantly higher daily food consumption (+39%) and lower serum estradiol levels (-49%, P = 0.079) compared with CC. Proximal tibia bone mineral content and cortical bone area significantly declined over 28 days in HU animals (-4.0 and 4.8%, respectively), whereas total and cancellous bone mineral densities were unchanged. HU animals had lower cortical bone formation rates and mineralizing surface at tibial midshaft, whereas differences in similar properties were not detected in cancellous bone of the distal femur. These results suggest that cortical bone, rather than cancellous bone, is more prominently affected by unloading in skeletally mature retired breeder female rats.

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

    PubMed

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

    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 microm) than in cortical BMG (5-15 microm), 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.

  11. Changes in canine cortical and cancellous bone mechanical properties following immobilization and remobilization with exercise.

    PubMed

    Kaneps, A J; Stover, S M; Lane, N E

    1997-11-01

    The purpose of this study was to assess cortical and cancellous bone responses to unilateral limb immobilization and, subsequently, to remobilization with exercise, in a young adult canine model. Right forelimbs of 14 1-2-year old mongrel dogs were immobilized in a non-weight-bearing position by a bandage for 16 weeks. Six control dogs were untreated. At 16 weeks, seven immobilized and three control dogs were euthanized. The remaining seven immobilized dogs began a recovery protocol consisting of 16 weeks of kennel confinement (without the right forelimb bandaged) followed by 16 weeks of treadmill exercise conducted three times per week. These seven dogs and three control dogs were euthanized at 48 weeks. Bone mineral density of the proximal radii was determined with dual-energy X-ray absorptiometry and humeral middiaphyseal cross-sectional areas were determined with computed tomography. Humeri were tested in cranio-caudal three-point bending to failure. Cancellous bone cores from the lateral humeral condyles had wet apparent density determined and were tested to failure in compression. Mechanical properties, bone density, and cross-sectional areas were compared between immobilized (right forelimb), contralateral weight bearing (left forelimb), and control forelimbs with Kruskal-Wallis and post hoc tests. At 16 weeks, bone mineral density, cortical load, yield, and stiffness as well as cancellous bone failure stress, yield stress, and modulus were significantly lower (p < 0.02) for immobilized limbs than control limbs. Immobilized limb cancellous bone mechanical properties were 28%-74% of control values, and cortical bone mechanical properties were 71%-98% of control values. After 32 weeks of remobilization, cortical and cancellous bone mechanical properties were not different from control values except that cortical bone failure stress and modulus were significantly higher (p < 0.01) between remobilized and control limbs. In summary, 16 weeks of forelimb

  12. Adaptation of Cancellous Bone to Aging and Immobilization in Growing Rats

    NASA Technical Reports Server (NTRS)

    Chen, Meng Meng; Jee, Webster S. S.; Ke, Hua Zhu; Lin, Bia Yun; Li, Qing Nan; Li, Xiao Jian

    1992-01-01

    Two-and-a half month-old female rats were subjected to right hindlimb immobilization or served as controls for 0, 1, 2, 8, 14, and 20 weeks. The right hindlimb was immobilized by bandaging it against the abdomen, thus unloading it. Cancellous bone histomorphometry was performed on microradiographs and double-fluorescent labeled 20 micron sections of the distal femoral metaphyses. Primary spongiosa bone loss occurred rapidly by 2 weeks, and secondary spongiosa bone loss occurred rapidly by 8 weeks of immobilization, and then equilibrated at 60% less bone mass than age-related controls. The negative bone balance induced by immobilization was caused by transient increase in bone resorption, decrease in bone formation, and longitudinal bone growth. The dynamic data of secondary spongiosa cancellous bone showed that percent eroded perimeter was transiently elevated by 55% to 82% between 1 and 8 weeks, percent labeled perimeter was transiently depressed by 32% to 50% between 1 and 14 weeks, mineral apposition rate was depressed by 23% and 19% at 1 and 2 weeks, and bone formation rate-bone area referent was transiently depressed by 35% and 59%c at 1 and 2 weeks. All the above parameters were at age-related control levels by 20 weeks of immobilization. However, bone formation rate-tissue area referent was depressed (-65%) throughout the study. Immobilization depressed completely longitudinal bone growth by 2 weeks and remained so. Only 0.65 mm of new metaphysis was generated in the immobilized versus 2.1 mm in controls during the study period. The immobilization induced an early cancellous bone loss which equilibrated at a new steady state with less bone and a normal (age-related control) bone turnover rate. When these findings were compared to an earlier study of 9 month-old virgin females subjected to right hindlimb immobilization up to 26 weeks, we found the adaptive responses of the cancellous bone were identical except that they occurred earlier and equilibrated

  13. Adaptation of Cancellous Bone to Aging and Immobilization in Growing Rats

    NASA Technical Reports Server (NTRS)

    Chen, Meng-Meng; Jee, Webster S. S.; Ke, Hua-Zhu; Lin, Bai-Yun; Li, Qing-Nan; Li, Xiao-Jian

    1992-01-01

    Two-and-half-month-old female rats were subjected to right hindlimb immobilization or served as controls for 0, 1, 2, 8, 14, and 20 weeks. The right hindlimb was immobilized by bandaging it against the abdomen, thus unloading it. Cancellous bone histomorphometry was performed on microradiographs and double-fluorescent labeled 20 tLm sections of the distal femoral metaphyses. Primary spongiosa bone loss occurred rapidly by 2 weeks, and secondary spongiosa bone loss occurred rapidly by 8 weeks of immobilization, and then equilibrated at 60% less bone mass than age-related controls. The negative bone balance induced by immobilization was caused by transient increase in bone resorption, decrease in bone formation, and longitudinal bone growth. The dynamic data of secondary spongiosa cancellous bone showed that percent eroded perimeter was transiently elevated by 55 to 82% between 1 and 8 weeks, percent labeled perimeter was transiently depressed by 32% to 50% between 1 and 14 weeks, mineral apposition rate was depressed by 23% and 19% at I and 2 weeks, and bone formation rate-bone area referent was transiently depressed by 35% and 59% at 1 and 2 weeks. All the above parameters were at age-related control levels by 20 weeks of immobiliza- tion. However, bone formation rate-tissue area referent was depressed (-65%) throughout the study. Immobilization depressed completely longitudinal bone growth by 2 weeks and remained so. Only 0.65 mm of new metaphysis was generated in the immobilized versus 2.1 mm in controls during the study period. The immobilization induced an early cancellous bone loss which equilibrated at a new steady state with less bone and a normal (age-related control) bone turnover rate. When these findings were compared to an earlier study of 9-month-old virgin females subjected to right hindlimb immobilization up to 26 weeks, we found the adaptive responses of the cancellous bone were identical except that they occurred earlier and equilibrated sooner in

  14. Directional tortuosity as a predictor of modulus damage for vertebral cancellous bone.

    PubMed

    Fyhrie, David P; Zauel, Roger

    2015-01-01

    There are many methods used to estimate the undamaged effective (apparent) moduli of cancellous bone as a function of bone volume fraction (BV/TV), mean intercept length(MIL), and other image based average microstructural measures. The MIL and BV/TV are both only functions of the cancellous microstructure and, therefore, cannot directly account for damage induced changes in the intrinsic trabecular hard tissue mechanical properties. Using a nonlinear finite element (FE) approximation for the degradation of effective modulus as a function of applied effective compressive strain, we demonstrate that a measurement of the directional tortuosity of undamaged trabecular hard tissue strongly predicts directional effective modulus (r2>0.90) and directional effective modulus degradation (r2>0.65). This novel measure of cancellous bone directional tortuosity has the potential for development into an anisotropic approach for calculating effective mechanical properties as a function of trabecular level material damage applicable to understanding how tissue microstructure and intrinsic hard tissue moduli interact to determine cancellous bone quality.

  15. Optimized demineralization of human cancellous bone by application of a vacuum.

    PubMed

    Eagle, Mark J; Rooney, Paul; Kearney, John N

    2015-07-01

    Human demineralized bone matrix derived from cortical bone is used by surgeons due to its ability to promote bone formation. There is also a need for shaped demineralized bone matrices made from cancellous bone, where the properties of the material allow its insertion into defects, therefore acting as a void filler and scaffold onto which new bone can form. In this study, we report that demineralized bone sponges were prepared by dissecting and cutting knee bone into cancellous bone cubes of 1 cm(3) . These cubes were then taken through a series of warm water washes, some with sonication, centrifugation, and two decontamination chemical washes. The cubes were optimally demineralized into sponges with 0.5N hydrochloric acid under vacuum with constant pH measurement. Demineralization was confirmed by quantitative measurement of calcium and qualitatively by compression. The sponges were freeze dried before terminal sterilisation with a target dose of 25 kGy gamma radiation whilst frozen. Samples of the sponges were histologically examined for calcium and collagen and also tested for osteoinductivity. Data showed well defined collagen staining in the sponges, with little residual calcium. Sponges from two out of three donors demonstrated osteoinductivity when implanted into the muscle of an athymic mouse.

  16. Association of microstructural and mechanical properties of cancellous bone and their fracture risk assessment tool scores.

    PubMed

    Wu, Dengke; Li, Xin; Tao, Cheng; Dai, Ruchun; Ni, Jiangdong; Liao, Eryuan

    2015-01-01

    This study is to investigate the association between fracture probabilities determined by using the fracture risk assessment tool (FRAX) and the microstructure and mechanical properties of femoral bone trabecula in osteoporosis (OP) and osteoarthritis (OA) patients with hip replacements. By using FRAX, we evaluated fracture risks of the 102 patients with bone replacements. Using micro CT scanning, we obtained the analysis parameters of microstructural properties of cancellous bone. Through morphometric observations, fatigue tests and compression tests, we obtained parameters of mechanical properties of cancellous bones. Relevant Pearson analysis was performed to investigate the association between the fracture probability and the microstructure and mechanical properties of femoral bone trabecula in patients. Fifteen risk factors in FRAX were compared between OP and OA patients. FRAX hip fracture risk score and major osteoporotic in OP and OA patients were significantly different. FRAX was associated with tissue bone mineral density and volumetric bone mineral density. Our study suggests that the probabilities of major osteoporotic and hip fracture using FRAX is associated with bone mass but not with micro bone quality. PMID:26064297

  17. Fast characterization of two ultrasound longitudinal waves in cancellous bone using an adaptive beamforming technique.

    PubMed

    Taki, Hirofumi; Nagatani, Yoshiki; Matsukawa, Mami; Mizuno, Katsunori; Sato, Toru

    2015-04-01

    The received signal in through-transmission ultrasound measurements of cancellous bone consists of two longitudinal waves, called the fast and slow waves. Analysis of these fast and slow waves may reveal characteristics of the cancellous bone that would be good indicators of osteoporosis. Because the two waves often overlap, decomposition of the received signal is an important problem in the characterization of bone quality. This study proposes a fast and accurate decomposition method based on the frequency domain interferometry imaging method with a modified wave transfer function that uses a phase rotation parameter. The proposed method accurately characterized the fast and slow waves in the experimental study, and the residual intensity, which was normalized with respect to the received signal intensity, was less than -20 dB over the bone specimen thickness range from 6 to 15 mm. In the simulation study, the residual intensity was less than -20 dB over the specimen thickness range from 3 to 8 mm. Decomposition of a single received signal takes only 5 s using a laptop personal computer with a single central processing unit. The proposed method has great potential to provide accurate and rapid measurements of indicators of osteoporosis in cancellous bone.

  18. Development and validation of a multiecho computer simulation of ultrasound propagation through cancellous bone

    NASA Astrophysics Data System (ADS)

    Langton, Christian; Church, Luke

    2002-05-01

    Cancellous bone consists of a porous open-celled framework of trabeculae interspersed with marrow. Although the measurement of broadband ultrasound attenuation (BUA) has been shown to be sensitive to osteoporotic changes, the exact dependence on material and structural parameters has not been elucidated. A 3-D computer simulation of ultrasound propagation through cancellous bone has been developed, based upon simple reflective behavior at the multitude of trabecular/marrow interfaces. A cancellous bone framework is initially described by an array of bone and marrow elements. An ultrasound pulse is launched along each row of the model with partial reflection occurring at each bone/marrow interface. If a reverse direction wave hits an interface, a further forward (echo) wave is created, with phase inversion implemented if appropriate. This process is monitored for each wave within each row. The effective received signal is created by summing the time domain data, thus simulating detection by a phase-sensitive ultrasound transducer, as incorporated in clinical systems. The simulation has been validated on a hexagonal honeycomb design of variable mesh size, first against a commercial computer simulation solution (Wave 2000 Pro), and second, via experimental measurement of physical replicas produced by stereolithography.

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

    PubMed Central

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

    2016-01-01

    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. PMID:26929343

  20. Phase velocity and attenuation predictions of waves in cancellous bone using an iterative effective medium approximation.

    PubMed

    Potsika, Vassiliki T; Protopappas, Vasilios C; Vavva, Maria G; Polyzos, Demosthenes; Fotiadis, Dimitrios I

    2013-01-01

    The quantitative determination of wave dispersion and attenuation in bone is an open research area as the factors responsible for ultrasound absorption and scattering in composite biological tissues have not been completely explained. In this study, we use the iterative effective medium approximation (IEMA) proposed in [1] so as to calculate phase velocity and attenuation in media with properties similar to those of cancellous bones. Calculations are performed for a frequency range of 0.4-0.8 MHz and for different inclusions' volume concentrations and sizes. Our numerical results are compared with previous experimental findings so as to assess the effectiveness of IEMA. It was made clear that attenuation and phase velocity estimations could provide supplementary information for cancellous bone characterization. PMID:24111396

  1. Progressive femoral cortical and cancellous bone density loss after uncemented tapered-design stem fixation

    PubMed Central

    Nowak, Tobias E; Haeberle, Lothar; Mueller, Lars P; Kress, Alexander; Voelk, Michael; Pfander, David; Forst, Raimund; Schmidt, Rainer

    2010-01-01

    Background Aseptic implant loosening and periprosthetic bone loss are major problems after total hip arthroplasty (THA). We present an in vivo method of computed tomography (CT) assisted osteodensitometry after THA that differentiates between cortical and cancellous bone density (BD) and area around the femoral component. Method Cortical and cancellous periprosthetic femoral BD (mg CaHA/mL), area (mm2) and contact area between the prothesis and cortical bone were determined prospectively in 31 patients 10 days, 1 year, and 6 years after uncemented THA (mean age at implantation: 55 years) using CT-osteodensitometry. Results 6 years postoperatively, cancellous BD had decreased by as much as 41% and cortical BD by up to 27% at the metaphyseal portion of the femur; this decrease was progressive between the 1-year and 6-year examinations. Mild cortical hypertrophy was observed along the entire length of the diaphysis. No statistically significant changes in cortical BD were observed along the diaphysis of the stem. Interpretation Periprosthetic CT-assisted osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Continuous loss of cortical and cancellous BD at the femoral metaphysis, a homeostatic cortical strain configuration, and mild cortical hypertrophy along the diaphysis suggest a diaphyseal fixation of the implanted stem. CT-assisted osteodensitometry has the potential to become an effective instrument for quality control in THA by means of in vivo determination of periprosthetic BD, which may be a causal factor in implant loosening after THA. PMID:20180716

  2. Reward Improves Cancellation and Restraint Inhibition across Childhood and Adolescence

    ERIC Educational Resources Information Center

    Sinopoli, Katia J.; Schachar, Russell; Dennis, Maureen

    2011-01-01

    Inhibitory control allows for the regulation of thought and action and interacts with motivational variables, such as reward, to modify behavior adaptively as environments change. The authors examined the effects of reward on two distinct forms of inhibitory control, cancellation and restraint. Typically developing children and adolescents…

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

    PubMed

    Kristensen, Helene Bjoerg; Andersen, Thomas Levin; Marcussen, Niels; Rolighed, Lars; Delaisse, Jean-Marie

    2013-03-01

    Vascularization is a prerequisite for osteogenesis in a number of situations, including bone development, fracture healing, and cortical bone remodeling. It is unknown whether a similar link exists between cancellous bone remodeling and vascularization. Here, we show an association between remodeling sites, capillaries, proliferative cells, and putative osteoblast progenitors. Iliac crest biopsies from normal human individuals were subjected to histomorphometry and immunohistochemistry to identify the respective positions of bone remodeling sites, CD34-positive capillaries, smooth muscle actin (SMA)-positive putative osteoblast progenitors, including pericytes, Ki67-positive proliferative cells, and bone remodeling compartment (BRC) canopies. The BRC canopy is a recently described structure separating remodeling sites from the bone marrow, consisting of CD56-positive osteoblasts at an early differentiation stage. We found that bone remodeling sites were associated with a significantly increased presence of capillaries, putative osteoblast progenitors, and proliferative cells in a region within 50 µm of the bone or the canopy surface. The increases were the highest above eroded surfaces and at the level of the light-microscopically assessed contact of these three entities with the bone or canopy surfaces. Between 51 and 100 µm, their densities leveled to that found above quiescent surfaces. Electron microscopy asserted the close proximity between BRC canopies and capillaries lined by pericytes. Furthermore, the BRC canopy cells were found to express SMA. These ordered distributions support the existence of an osteogenic-vascular interface in adult human cancellous bone. The organization of this interface fits the current knowledge on the mode of action of vasculature on osteogenesis, and points to the BRC canopy as a central player in this mechanism. We propose a model where initiation of bone remodeling coincides with the induction of proximity of the

  4. Optimizing bone health in children and adolescents.

    PubMed

    Golden, Neville H; Abrams, Steven A

    2014-10-01

    The pediatrician plays a major role in helping optimize bone health in children and adolescents. This clinical report reviews normal bone acquisition in infants, children, and adolescents and discusses factors affecting bone health in this age group. Previous recommended daily allowances for calcium and vitamin D are updated, and clinical guidance is provided regarding weight-bearing activities and recommendations for calcium and vitamin D intake and supplementation. Routine calcium supplementation is not recommended for healthy children and adolescents, but increased dietary intake to meet daily requirements is encouraged. The American Academy of Pediatrics endorses the higher recommended dietary allowances for vitamin D advised by the Institute of Medicine and supports testing for vitamin D deficiency in children and adolescents with conditions associated with increased bone fragility. Universal screening for vitamin D deficiency is not routinely recommended in healthy children or in children with dark skin or obesity because there is insufficient evidence of the cost-benefit of such a practice in reducing fracture risk. The preferred test to assess bone health is dual-energy x-ray absorptiometry, but caution is advised when interpreting results in children and adolescents who may not yet have achieved peak bone mass. For analyses, z scores should be used instead of T scores, and corrections should be made for size. Office-based strategies for the pediatrician to optimize bone health are provided. This clinical report has been endorsed by American Bone Health. PMID:25266429

  5. Three dimensional stereolithography models of cancellous bone structures from muCT data: testing and validation of finite element results.

    PubMed

    Dobson, C A; Sisias, G; Phillips, R; Fagan, M J; Langton, C M

    2006-04-01

    Stereolithography (STL) models of complex cancellous bone structures have been produced from three-dimensional micro-computed tomography data sets of human cancellous bone histological samples from four skeletal sites. The STL models have been mechanically tested and the derived stiffness compared with that predicted by finite element analysis. The results show a strong correlation (R2 = 0.941) between the predicted and calculated stiffnesses of the structures and show promise for the use of STL as an additional technique to complement the use of finite element models, for the assessment of the mechanical properties of complex cancellous bone structures.

  6. Effect of cancellous bone on the functionally graded dental implant concept.

    PubMed

    Hedia, H S

    2005-01-01

    In a previous work by the author [H.S. Hedia and M. Nemat-Alla, Design optimization of functionally graded dental implant, submitted to be published in the J. Bio-Medical Materials and Engineering], a functionally graded material dental implant was designed without cansellous bone in the model. In this investigation the effect of presence cancellous bone as a thin layer around the dental implant was investigated. It is well known that the main inorganic component of natural bone is hydroxyapatite (HAP) and that the main organic component is collagen (Col). Hydroxyapatite HAP implants are not bioabsorbable, and because induction of bone into and around the artificially made HAP is not always satisfactory, loosening or breakage of HAP implants may occur after implantation in the clinical application. The development of a new material which is bioabsorbable and which has osteoconductive activity is needed. Therefore, the aim of the current investigation is to design an implant, in the presence of cancellous bone as a thin layer around it, from functionally graded material. In this study, a novel biomaterial, collagen/hydroxyapatite (Col/HAP) as a functionally graded material (FGM), was developed using the finite element and optimization techniques which are available in the ANSYS package. These materials have a self-organized character similar to that of natural bone. The investigations have shown that the maximum stress in the cortical bone and cancellous bone for the Col/HAP functionally graded implant has been reduced by about 40% and 19% respectively compared to currently used titanium dental implants.

  7. Intermittent PTH administration and mechanical loading are anabolic for periprosthetic cancellous bone.

    PubMed

    Grosso, Matthew J; Courtland, Hayden-William; Yang, Xu; Sutherland, James P; Stoner, Kirsten; Nguyen, Joseph; Fahlgren, Anna; Ross, F Patrick; van der Meulen, Marjolein C H; Bostrom, Mathias P

    2015-02-01

    The purpose of this study was to determine the individual and combined effects on periprosthetic cancellous bone of intermittent parathyroid hormone administration (iPTH) and mechanical loading at the cellular, molecular, and tissue levels. Porous titanium implants were inserted bilaterally on the cancellous bone of adult rabbits beneath a loading device attached to the distal lateral femur. The left femur received a sham loading device. The right femur was loaded daily, and half of the rabbits received daily PTH. Periprosthetic bone was evaluated up to 28 days for gene expression, histology, and µCT analysis. Loading and iPTH increased bone mass by a combination of two mechanisms: (1) Altering cell populations in a pro-osteoblastic/anti-adipocytic direction, and (2) controlling bone turnover by modulating the RANKL-OPG ratio. At the tissue level, BV/TV increased with both loading (+53%, p < 0.05) and iPTH (+54%, p < 0.05). Combined treatment showed only small additional effects at the cellular and molecular levels that corresponded to a small additive effect on bone volume (+13% compared to iPTH alone, p > 0.05). This study suggests that iPTH and loading are potential therapies for enhancing periprosthetic bone formation. The elucidation of the cellular and molecular response may help further enhance the combined therapy and related targeted treatment strategies. PMID:25408434

  8. Numerical investigation of ultrasound reflection and backscatter measurements in cancellous bone on various receiving areas.

    PubMed

    Hosokawa, Atsushi

    2014-07-01

    In this study, new ultrasound reflection and backscatter measurements in cancellous bone using a membrane-type hydrophone are proposed. A membrane hydrophone made of a piezoelectric polymer film mounted on an annular frame allows an incident ultrasound wave to pass through its aperture because it has no backing material. Therefore, in measurements using the membrane hydrophone, the receiving area could be located independently from the transmitting area. In addition, the size and shape of the receiving area, which corresponded to those of the electrode deposited on the piezoelectric film, could be arranged in various ways. To investigate the validity of the proposed measurements, before bench-top experiments, the reflected and backscattered waves from cancellous bone were numerically simulated using a finite-difference time-domain method. The reflection and backscatter parameters were measured on various receiving areas, and their correlation coefficients with the structural parameters in the cancellous bone were derived. The simulated results suggested that appropriate receiving areas for the reflection and backscatter measurements could exist and that the proposed measurements could be more effective for evaluating bone properties than conventional measurements.

  9. Signal of Interest Selection Standard for Ultrasonic Backscatter in Cancellous Bone Evaluation.

    PubMed

    Liu, Chengcheng; Tang, Tao; Xu, Feng; Ta, Dean; Matsukawa, Mami; Hu, Bo; Wang, Weiqi

    2015-10-01

    The aim of this study was to examine the effect of the backscattered signal of interest (SOI) on ultrasonic cancellous bone evaluation. In vitro backscatter measurements were performed using 16 bovine cancellous bone specimens and six different transducers with central frequencies of 0.5, 1, 2.25, 3.5, 5 and 10 MHz. The SOI for signal analysis was selected by a rectangular window. The delay (T1) and duration (T2) of the time window were varied, and the apparent integrated backscatter (AIB) and its correlation to bone volume fraction (BV/TV) were calculated. The results indicate that in addition to affecting the measured value of AIB, the SOI influences the observed correlation between AIB and BV/TV. Strong positive correlations were observed for short T1 (0.5 MHz: ≤6 μs, 1 MHz: ≤3 μs, 2.25 and 3.5 MHz: ≤2 μs, 5 and 10 MHz: ≤1 μs). However, strong negative correlations were observed when T1 was long (0.5 MHz: >9 μs, 1 MHz: >7 μs, 2.25 and 3.5 MHz: >3 μs, 5 and 10 MHz: >2 μs). The T2 value, especially low values (≤3 μs), also influenced the correlation coefficients. Positive correlations were more commonly observed at lower frequencies (i.e., 0.5-1 MHz), whereas negative correlations were more common at higher frequencies (i.e., 2.25-10 MHz). An explicit standard for in vitro SOI selection and cancellous bone assessment was proposed for a broad frequency range (0.5-10 MHz). Current conflicting findings are explained, and constructive suggestions for ultrasonic backscatter cancellous bone evaluation are provided. PMID:26210784

  10. Prostaglandin E2 Prevents Ovariectomy-Induced Cancellous Bone Loss in Rats

    NASA Technical Reports Server (NTRS)

    Ke, Hua Zhu; Li, Mei; Jee, Webster S. S.

    1992-01-01

    The object of this study was to determine whether prostaglandin E2, (PGE2) can prevent ovariectomy induced cancellous bone loss. Thirty-five 3-month-old female Sprague-Dawley rats were divided into two groups. The rats in the first group were ovariectomized (OVX) while the others received sham operation (sham-OVX). The OVX group was further divided into three treatment groups. The daily doses for the three groups were 0,1 and 6 mg PGE2/kg for 90 days. Bone histomorphometric analyses were performed on double-fluorescent-labeled undecalcified proximal tibial metaphysis (PTM). We confirmed that OVX induces massive cancellous bone loss (-80%) and a higher bone turnover (+143%). The new findings from the present study demonstrate that bone loss due to ovarian hormone deficiency can be prevented by a low-dose (1 mg) daily administration of PGE2. Furthermore, a higher-dose (6 mg) daily administration of PGE2 not only prevents bone loss but also adds extra bone to the proximal tibial metaphyses. PGE, at the 1-mg dose level significantly increased trabecular bone area, trabecular width, trabecular node density, density of node to node, ratio of node to free end, and thus significantly decreased trabecular separation from OVX controls. At this dose level, these same parameters did not differ significantly from sham-OVX controls. However, at the 6-mg dose level PGE2, there were significant increases in trabecular bone area, trabecular width, trabecular node density, density of node to node, and ratio of node to free end, while there was significant decrease in trabecular separation from both OVX and sham-operated controls. The changes in indices of trabecular bone microanatomical structure indicated that PGE2 prevented bone loss as well as the disconnection of existing trabeculae. In summary, PGE2, administration to OVX rats decreased bone turnover and increased bone formation parameters resulting in a positive bone balance that prevented bone loss (in both lower and higher

  11. Preliminary Normative Data on the Penn State University Symbol Cancellation Task With Nonconcussed Adolescents.

    PubMed

    Conder, Robert L; Conder, Alanna A; Register-Mihalik, Johna; Conder, Lauren H; Newton, Shannon

    2015-01-01

    Visual concentration impairment after neurologic injury is frequent, making its identification a critical component of neurocognitive concussion assessment. Visual target cancellation tests such as the Penn State University Symbol Cancellation Task (PSUSCT) have been widely used in assessing professional and collegiate athletes. To date, there are no normative studies using the PSUSCT with an adolescent population. Given that 38 million children and adolescents participate in sports and an estimated 5% to 10% are concussed annually, adolescent normative data are critically needed to evaluate concussions in this vulnerable population. The purpose of this study was to provide adolescent normative data on the PSUSCT. Participants included 40 healthy, nonconcussed high school students aged 14 to 19 years old (20 men, 20 women). Participants were administered Forms A and C of the PSUSCT within a 4-day period. Data analysis examined hits, omission errors, and commission errors, with descriptive statistics calculated for the total sample and for subgroups by gender and age. Study 1 provided normative adolescent data on Form A. Study 2 examined practice effects and established reliable change indexes (RCIs) by comparing results on Forms A and C. Neither Study 1 nor Study 2 demonstrated significant group differences for gender or age. In conclusion, this study presents adolescent normative data, apparent practice effects, and RCIs on the PSUSCT. These norms provide data needed to appropriately include the PSUSCT in baseline and postinjury concussion evaluation batteries with adolescent student-athletes. Findings should be replicated with a larger, more heterogeneous sample. PMID:25072106

  12. Fabrication and development of artificial osteochondral constructs based on cancellous bone/hydrogel hybrid scaffold.

    PubMed

    Song, Kedong; Li, Liying; Yan, Xinyu; Zhang, Yu; Li, Ruipeng; Wang, Yiwei; Wang, Ling; Wang, Hong; Liu, Tianqing

    2016-06-01

    Using tissue engineering techniques, an artificial osteochondral construct was successfully fabricated to treat large osteochondral defects. In this study, porcine cancellous bones and chitosan/gelatin hydrogel scaffolds were used as substitutes to mimic bone and cartilage, respectively. The porosity and distribution of pore size in porcine bone was measured and the degradation ratio and swelling ratio for chitosan/gelatin hydrogel scaffolds was also determined in vitro. Surface morphology was analyzed with the scanning electron microscope (SEM). The physicochemical properties and the composition were tested by using an infrared instrument. A double layer composite scaffold was constructed via seeding adipose-derived stem cells (ADSCs) induced to chondrocytes and osteoblasts, followed by inoculation in cancellous bones and hydrogel scaffolds. Cell proliferation was assessed through Dead/Live staining and cellular activity was analyzed with IpWin5 software. Cell growth, adhesion and formation of extracellular matrix in composite scaffolds blank cancellous bones or hydrogel scaffolds were also analyzed. SEM analysis revealed a super porous internal structure of cancellous bone scaffolds and pore size was measured at an average of 410 ± 59 μm while porosity was recorded at 70.6 ± 1.7 %. In the hydrogel scaffold, the average pore size was measured at 117 ± 21 μm and the porosity and swelling rate were recorded at 83.4 ± 0.8 % and 362.0 ± 2.4 %, respectively. Furthermore, the remaining hydrogel weighed 80.76 ± 1.6 % of the original dry weight after hydration in PBS for 6 weeks. In summary, the cancellous bone and hydrogel composite scaffold is a promising biomaterial which shows an essential physical performance and strength with excellent osteochondral tissue interaction in situ. ADSCs are a suitable cell source for osteochondral composite reconstruction. Moreover, the bi-layered scaffold significantly enhanced cell proliferation compared to the cells seeded on

  13. Fabrication and development of artificial osteochondral constructs based on cancellous bone/hydrogel hybrid scaffold.

    PubMed

    Song, Kedong; Li, Liying; Yan, Xinyu; Zhang, Yu; Li, Ruipeng; Wang, Yiwei; Wang, Ling; Wang, Hong; Liu, Tianqing

    2016-06-01

    Using tissue engineering techniques, an artificial osteochondral construct was successfully fabricated to treat large osteochondral defects. In this study, porcine cancellous bones and chitosan/gelatin hydrogel scaffolds were used as substitutes to mimic bone and cartilage, respectively. The porosity and distribution of pore size in porcine bone was measured and the degradation ratio and swelling ratio for chitosan/gelatin hydrogel scaffolds was also determined in vitro. Surface morphology was analyzed with the scanning electron microscope (SEM). The physicochemical properties and the composition were tested by using an infrared instrument. A double layer composite scaffold was constructed via seeding adipose-derived stem cells (ADSCs) induced to chondrocytes and osteoblasts, followed by inoculation in cancellous bones and hydrogel scaffolds. Cell proliferation was assessed through Dead/Live staining and cellular activity was analyzed with IpWin5 software. Cell growth, adhesion and formation of extracellular matrix in composite scaffolds blank cancellous bones or hydrogel scaffolds were also analyzed. SEM analysis revealed a super porous internal structure of cancellous bone scaffolds and pore size was measured at an average of 410 ± 59 μm while porosity was recorded at 70.6 ± 1.7 %. In the hydrogel scaffold, the average pore size was measured at 117 ± 21 μm and the porosity and swelling rate were recorded at 83.4 ± 0.8 % and 362.0 ± 2.4 %, respectively. Furthermore, the remaining hydrogel weighed 80.76 ± 1.6 % of the original dry weight after hydration in PBS for 6 weeks. In summary, the cancellous bone and hydrogel composite scaffold is a promising biomaterial which shows an essential physical performance and strength with excellent osteochondral tissue interaction in situ. ADSCs are a suitable cell source for osteochondral composite reconstruction. Moreover, the bi-layered scaffold significantly enhanced cell proliferation compared to the cells seeded on

  14. Architectural measures of the cancellous bone of the mandibular condyle identified by principal components analysis.

    PubMed

    Giesen, E B W; Ding, M; Dalstra, M; van Eijden, T M G J

    2003-09-01

    As several morphological parameters of cancellous bone express more or less the same architectural measure, we applied principal components analysis to group these measures and correlated these to the mechanical properties. Cylindrical specimens (n = 24) were obtained in different orientations from embalmed mandibular condyles; the angle of the first principal direction and the axis of the specimen, expressing the orientation of the trabeculae, ranged from 10 degrees to 87 degrees. Morphological parameters were determined by a method based on Archimedes' principle and by micro-CT scanning, and the mechanical properties were obtained by mechanical testing. The principal components analysis was used to obtain a set of independent components to describe the morphology. This set was entered into linear regression analyses for explaining the variance in mechanical properties. The principal components analysis revealed four components: amount of bone, number of trabeculae, trabecular orientation, and miscellaneous. They accounted for about 90% of the variance in the morphological variables. The component loadings indicated that a higher amount of bone was primarily associated with more plate-like trabeculae, and not with more or thicker trabeculae. The trabecular orientation was most determinative (about 50%) in explaining stiffness, strength, and failure energy. The amount of bone was second most determinative and increased the explained variance to about 72%. These results suggest that trabecular orientation and amount of bone are important in explaining the anisotropic mechanical properties of the cancellous bone of the mandibular condyle. PMID:14667134

  15. The use of bone graft substitutes in large cancellous voids: any specific needs?

    PubMed

    Faour, Omar; Dimitriou, Rozalia; Cousins, Charlotte A; Giannoudis, Peter V

    2011-09-01

    Bone graft is the second most common transplantation tissue, with blood being by far the commonest. Autograft is considered ideal for grafting procedures, providing osteoinductive growth factors, osteogenic cells and an osteoconductive scaffold. Limitations, however, exist regarding donor site morbidity and graft availability. Allograft on the other hand poses the risk of disease transmission. Synthetic graft substitutes lack osteoinductive or osteogenic properties. Composite grafts combine scaffolding properties with biological elements to stimulate cell proliferation and differentiation and eventually osteogenesis. We present here an overview of bone graft substitutes available for clinical application in large cancellous voids.

  16. Transcriptional profiling of cortical versus cancellous bone from mechanically-loaded murine tibiae reveals differential gene expression.

    PubMed

    Kelly, Natalie H; Schimenti, John C; Ross, F Patrick; van der Meulen, Marjolein C H

    2016-05-01

    Mechanical loading is an anabolic stimulus that increases bone mass, and thus a promising method to counteract osteoporosis-related bone loss. The mechanism of this anabolism remains unclear, and needs to be established for both cortical and cancellous envelopes individually. We hypothesized that cortical and cancellous bone display different gene expression profiles at baseline and in response to mechanical loading. To test this hypothesis, the left tibiae of 10-week-old female C57Bl/6 mice were subjected to one session of axial tibial compression (9N, 1200cycles, 4Hz triangle waveform) and euthanized 3 and 24h following loading. The right limb served as the contralateral control. We performed RNA-seq on marrow-free metaphyseal samples from the cortical shell and the cancellous core to determine differential gene expression at baseline (control limb) and in response to load. Differential expression was verified with qPCR. Cortical and cancellous bone exhibited distinctly different transcriptional profiles basally and in response to mechanical loading. More genes were differentially expressed with loading at 24h with more genes downregulated at 24h than at 3h in both tissues. Enhanced Wnt signaling dominated the response in cortical bone at 3 and 24h, but in cancellous bone only at 3h. In cancellous bone at 24h many muscle-related genes were downregulated. These findings reveal key differences between cortical and cancellous genetic regulation in response to mechanical loading. Future studies at different time points and multiple loading sessions will add to our knowledge of cortical and cancellous mechanotransduction with the potential to identify new targets for mouse genetic knockout studies and drugs to treat osteoporosis. PMID:26876048

  17. Improvement of cancellous bone microstructure in patients on teriparatide following alendronate pretreatment.

    PubMed

    Fahrleitner-Pammer, Astrid; Burr, David; Dobnig, Harald; Stepan, Jan J; Petto, Helmut; Li, Jiliang; Krege, John H; Pavo, Imre

    2016-08-01

    An increase in procollagen type I amino-terminal propeptide (PINP) early after teriparatide initiation was shown to correlate with increased lumbar spine areal BMD and is a good predictor of the anabolic response to teriparatide. Few data exist correlating PINP and bone microstructure, and no data exist in patients on teriparatide following prior potent antiresorptive treatment. This exploratory analysis aimed to investigate the effects of teriparatide on cancellous bone microstructure and correlations of bone markers with microstructure in alendronate-pretreated patients. This was a post hoc analysis of changes in bone markers and three-dimensional indices of bone microstructure in paired iliac crest biopsies from a prospective teriparatide treatment study in postmenopausal women with osteoporosis who were either treatment-naïve (TN, n=16) or alendronate-pretreated (ALN, n=29) at teriparatide initiation. Teriparatide (20μg/day) was given for 24months; biopsies were taken at baseline and endpoint, and serum concentrations of PINP and type 1 collagen cross-linked C-telopeptide (βCTX) were measured at intervals up to 24months. In the TN and ALN groups, respectively, mean (SD) increases in three-dimensional bone volume/tissue volume were 105 (356)% (P=0.039) and 55 (139)% (P<0.005) and trabecular thickness 30.4 (30)% (P<0.001) and 30.8 (53)% (P<0.001). No significant changes were observed in trabecular number or separation. In the ALN patients, 3-month change of neither PINP nor βCTX correlated with indices of cancellous bone microstructure. However, 12-month changes in biochemical bone markers correlated significantly with improvements in bone volume/tissue volume, r=0.502 (P<0.01) and r=0.378 (P<0.05), trabecular number, r=0.559 (P<0.01) and r=0.515 (P<0.01), and reduction of trabecular separation, r=-0.432 (P<0.05) and r=-0.530 (P<0.01), for PINP and βCTX, respectively. We conclude that cancellous bone microstructure improved with teriparatide therapy

  18. Improvement of cancellous bone microstructure in patients on teriparatide following alendronate pretreatment.

    PubMed

    Fahrleitner-Pammer, Astrid; Burr, David; Dobnig, Harald; Stepan, Jan J; Petto, Helmut; Li, Jiliang; Krege, John H; Pavo, Imre

    2016-08-01

    An increase in procollagen type I amino-terminal propeptide (PINP) early after teriparatide initiation was shown to correlate with increased lumbar spine areal BMD and is a good predictor of the anabolic response to teriparatide. Few data exist correlating PINP and bone microstructure, and no data exist in patients on teriparatide following prior potent antiresorptive treatment. This exploratory analysis aimed to investigate the effects of teriparatide on cancellous bone microstructure and correlations of bone markers with microstructure in alendronate-pretreated patients. This was a post hoc analysis of changes in bone markers and three-dimensional indices of bone microstructure in paired iliac crest biopsies from a prospective teriparatide treatment study in postmenopausal women with osteoporosis who were either treatment-naïve (TN, n=16) or alendronate-pretreated (ALN, n=29) at teriparatide initiation. Teriparatide (20μg/day) was given for 24months; biopsies were taken at baseline and endpoint, and serum concentrations of PINP and type 1 collagen cross-linked C-telopeptide (βCTX) were measured at intervals up to 24months. In the TN and ALN groups, respectively, mean (SD) increases in three-dimensional bone volume/tissue volume were 105 (356)% (P=0.039) and 55 (139)% (P<0.005) and trabecular thickness 30.4 (30)% (P<0.001) and 30.8 (53)% (P<0.001). No significant changes were observed in trabecular number or separation. In the ALN patients, 3-month change of neither PINP nor βCTX correlated with indices of cancellous bone microstructure. However, 12-month changes in biochemical bone markers correlated significantly with improvements in bone volume/tissue volume, r=0.502 (P<0.01) and r=0.378 (P<0.05), trabecular number, r=0.559 (P<0.01) and r=0.515 (P<0.01), and reduction of trabecular separation, r=-0.432 (P<0.05) and r=-0.530 (P<0.01), for PINP and βCTX, respectively. We conclude that cancellous bone microstructure improved with teriparatide therapy

  19. Determining the modulus of intact bovine vertebral cancellous bone tissue: Development and validation of a protocol

    NASA Astrophysics Data System (ADS)

    Engbretson, Andrew Craig

    Cancellous, or spongy, bone accounts for nearly 80% of the human skeleton's internal surface area, despite comprising only 20% of its mass. It is made up of a network of struts and plates that provide lightweight internal support to mammalian bones. In addition, it often serves as the main interface between the skeletal system and implanted devices such as artificial hips, knees, and fracture fixation devices. However, hip arthroplasties can succumb to loosening of the implant due to bone resorption, which is thought to be caused by a mismatch in both apparent and real stiffness between the device and the surrounding bone. Many studies have attempted to determine the Young's modulus of cancellous bone tissue, but the results are far from being in agreement. Reported values range from less than 1 to nearly 20 GPa. In addition, the small size of trabeculae has made dissection and testing a challenge. In this thesis, whole individual trabeculae from a bovine lumbar spine were tested in three-point bending to determine their Young's modulus using custom-made equipment to fit a miniature single-axis testing device. The device itself was validated by testing materials with moduli ranging from 1 to 200 GPa. The structure of the cancellous bone and the morphology of the individual struts were determined using micro x-ray computed tomography (muXCT). Individual struts were manually isolated from slices made using a low-speed saw under constant lubrication and measured under a stereomicroscope. Samples exhibiting no machined surfaces (and thus deemed to be whole, or "uncut" were compared to struts that had been cut by the saw during sectioning. Validation showed that the system was capable of determining the modulus of materials that were approximately five times stiffer than the expected cancellous modulus (copper, at 115 GPa) to within 10% of published values. This gave confidence in the results for bone. The modulus of the "uncut" specimens was found to be 15.28 2.26 GPa

  20. Mechanical properties of cancellous bone in the human mandibular condyle are anisotropic.

    PubMed

    Giesen, E B; Ding, M; Dalstra, M; van Eijden, T M

    2001-06-01

    The objective of the present study was (1) to test the hypothesis that the elastic and failure properties of the cancellous bone of the mandibular condyle depend on the loading direction, and (2) to relate these properties to bone density parameters. Uniaxial compression tests were performed on cylindrical specimens (n=47) obtained from the condyles of 24 embalmed cadavers. Two loading directions were examined, i.e., a direction coinciding with the predominant orientation of the plate-like trabeculae (axial loading) and a direction perpendicular to the plate-like trabeculae (transverse loading). Archimedes' principle was applied to determine bone density parameters. The cancellous bone was in axial loading 3.4 times stiffer and 2.8 times stronger upon failure than in transverse loading. High coefficients of correlation were found among the various mechanical properties and between them and the apparent density and volume fraction. The anisotropic mechanical properties can possibly be considered as a mechanical adaptation to the loading of the condyle in vivo. PMID:11470118

  1. A retrospective analysis evaluating allogeneic cancellous bone sponge for foot and ankle arthrodesis.

    PubMed

    Brigido, Stephen A; Bleazey, Scott T; Protzman, Nicole M; D'Angelantonio, Albert; Schoenhaus, Harold D

    2013-01-01

    The present retrospective case crossover study was conducted to determine the effectiveness and safety data associated with the use of an allogeneic, cancellous bone sponge in an orthopedic foot and ankle population. We reviewed the medical records of 47 subjects (80 joints) who had undergone foot and/or ankle fusion with the cancellous bone sponge. The records were reviewed up to 12 months postoperatively. The joints included in the present study were 12 ankles, 3 ankle syndesmotic fusions (with concurrent total ankle arthroplasty), 17 subtalar joints, 17 talonavicular joints, 9 calcaneocubiod joints, 1 naviculocuneiform joint, 13 first tarsometatarsal joints, 6 lesser tarsometatarsal joints, and 2 first metatarsophalangeal joints. The endpoints of the present study were solid, sustained foot and ankle fusion, as demonstrated radiographically, and the occurrence of unexpected adverse effects related to the graft. The fusion rates were compared with those reported in other studies. The patient-reported outcome variables for the present study included the visual analog pain scale and the American Orthopaedic Foot and Ankle Score. The use of a cancellous sponge showed statistically significant improvements in pain and function and comparable or better fusion rates compared with outcomes reported in other published reports.

  2. Compressive properties of commercially available polyurethane foams as mechanical models for osteoporotic human cancellous bone

    PubMed Central

    Patel, Purvi SD; Shepherd, Duncan ET; Hukins, David WL

    2008-01-01

    Background Polyurethane (PU) foam is widely used as a model for cancellous bone. The higher density foams are used as standard biomechanical test materials, but none of the low density PU foams are universally accepted as models for osteoporotic (OP) bone. The aim of this study was to determine whether low density PU foam might be suitable for mimicking human OP cancellous bone. Methods Quasi-static compression tests were performed on PU foam cylinders of different lengths (3.9 and 7.7 mm) and of different densities (0.09, 0.16 and 0.32 g.cm-3), to determine the Young's modulus, yield strength and energy absorbed to yield. Results Young's modulus values were 0.08–0.93 MPa for the 0.09 g.cm-3 foam and from 15.1–151.4 MPa for the 0.16 and 0.32 g.cm-3 foam. Yield strength values were 0.01–0.07 MPa for the 0.09 g.cm-3 foam and from 0.9–4.5 MPa for the 0.16 and 0.32 g.cm-3 foam. The energy absorbed to yield was found to be negligible for all foam cylinders. Conclusion Based on these results, it is concluded that 0.16 g.cm-3 PU foam may prove to be suitable as an OP cancellous bone model when fracture stress, but not energy dissipation, is of concern. PMID:18844988

  3. Tissue-level remodeling simulations of cancellous bone capture effects of in vivo loading in a rabbit model.

    PubMed

    Morgan, Timothy G; Bostrom, Mathias P G; van der Meulen, Marjolein C H

    2015-03-18

    The adaptation of cancellous bone to mechanical stimuli occurs throughout normal skeletal growth and aging, as well as in response to surgery, disease and device implantation. Previously we developed an in vivo cancellous loading model in the distal lateral femur of the rabbit. In response to daily in vivo loading for four weeks, bone mass increased, trabeculae thickened and the apparent modulus of the underlying cancellous bone increased. Here, we simulated our prior in vivo rabbit loading experiment using a cell-based tissue remodeling algorithm (Mullender et al., 1994) and compared the results to the in vivo experimental data published previously. Cancellous bone tissue was added or removed from the surface of trabeculae in regions of high and low mechanical stimulus, respectively. To examine the effect of material properties on mechanically regulated adaptation, we implemented both a homogeneous material model and a model where the relative density of tissue was lower for new and surface bone tissue compared to interior tissue. The simulations captured the changes in histomorphometric parameters and mechanical properties measured in the in vivo experiment illustrating the ability of computational simulations to predict the effect of mechanically regulated adaptation on cancellous bone histomorphometry and apparent modulus. PMID:25579991

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Fully Threaded Versus Partially Threaded Screws: Determining Shear in Cancellous Bone Fixation.

    PubMed

    Downey, Michael W; Kosmopoulos, Victor; Carpenter, Brian B

    2015-01-01

    Many researchers have studied and compared various forms of intraosseous fixation. No studies have examined the effects of shear through stiffness and failure strength of a fully threaded versus a partially threaded screw. Our hypothesis was that the fully threaded lag screw technique would provide greater shear strength and resistance. Thirty-six synthetic sawbone blocks were used to test screw fixation. In group 1 (n = 9), 2 blocks were fixed together using a fully threaded 4.0-mm stainless steel cancellous bone screw and the lag technique. In group 2 (n = 8), 2 blocks were fixed together using the standard manufacturer-recommended method for inserting 4.0-mm partially threaded stainless steel cancellous bone screws. The constructs were then mechanically tested. Shear was applied by compressing each construct at an axial displacement rate of 0.5 mm/s until failure. The fully threaded screw had a significantly greater (p = .026) initial stiffness (106.4 ± 15.8 N/mm) than the partially threaded screw (80.1 ± 27.5 N/mm). The yield load and displacement for the fully threaded group (429.4 ± 11.7 N and 7.2 ± 0.35 mm) were 64% and 67% greater than those for the partially threaded screw group (261.4 ± 26.1 N and 4.3 ± 1.03 mm), respectively. The results of the present study have demonstrated the importance of a full-thread construct to prevent shear and to decrease strain at the fracture. The confirmation of our hypothesis questions the future need and use of partially threaded screws for cancellous bone fixation. PMID:26210079

  6. Adolescence: the period of dramatic bone growth.

    PubMed

    Weaver, Connie M

    2002-02-01

    Adolescence is a period of rapid skeletal growth during which nearly half of the adult skeletal mass is accrued. This life stage is a window of opportunity for influencing peak bone mass and reducing the risk of osteoporosis later in life. Endocrine factors that may influence peak bone mass include insulin-like growth factor-1, which regulates skeletal growth, and gonadotropic hormones, which stimulate epiphyseal maturation. Estrogen deficiency and amenorrhea can reduce skeletal mass. Weight-bearing exercise can increase bone mass. Appropriate mineralization of the skeleton requires adequate dietary intakes of minerals involved in the formation of hydroxyapatite; the most likely to be deficient is calcium.

  7. Short- and long-term effects of vertebroplastic bone cement on cancellous bone.

    PubMed

    Quan, Renfu; Ni, Yueming; Zhang, Liang; Xu, Jinwei; Zheng, Xuan; Yang, Disheng

    2014-07-01

    Vertebroplasty using poly(methyl methacrylate) (PMMA) bone cement is the most common method to treat osteoporotic vertebral fractures. However, several questions of interest remain to be clarified, including how does PMMA affect the cement-bone interface area and surrounding bone tissue, can damaged bone tissues be repaired, how will PMMA change the bone interface over the long-term, and what happens to PMMA itself? The purpose of this study is to investigate these concerns and provide a basis for clinical evaluation. We made bone defects in the lumbar vertebrae of New Zealand rabbits as a model of osteoporosis and injected them with bone cement. A mechanical testing machine was used to perform axial compression, three-point bending, and twisting resistance tests to observe and investigate the short- and long-term biomechanical properties of PMMA after implantation. Optical, fluorescence, scanning electron microscopy, and nanoindentation were used to observe the changes in the interface microstructure. PMMA can rapidly establish the strong support with stable function in the near future. Biomechanical experiments showed that biomechanical property of bone cement group was significantly higher than those in the other two groups (P<0.05) biomechanical property of bone cement group may decline with the time, but it's still better than that of OP in the control group (P<0.05). Histomorphological observation result shows that under osteoporosis state the bone grows slower, also bone's rebuilding time extended. And in the later period, main bone's continuous osteoporosis has some impact on the interface. Nano-indentation testing shows that the young modulus and stiffness of the interface among bone, material and interface were significantly differences (P<0.05). Bone cement had gave the best nano indentation hardness, then was interface and bone tissue. PMMA bone cement was able to quickly support and stabilize the defect in the short term, and bone growth restarted at

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

    PubMed

    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.

  9. Effect of different sterilization processing methods on the mechanical properties of human cancellous bone allografts.

    PubMed

    Vastel, L; Meunier, A; Siney, H; Sedel, L; Courpied, J-P

    2004-05-01

    Use of new sterilization methods applied to human bone is likely to affect both the mechanical and biological properties of human cancellous grafts. The mechanical properties of the transplanted bone inevitably determine the short- and mid-term results of the orthopedic procedure performed. The aim of this study was to compare, under similar conditions, the mechanical effects of gamma irradiation, lipid extraction, and treatment with 6M urea on trabecular bone samples, through conventional mechanical tests and measurement of the ultrasound wave propagation rate. Deteriorations measured for gamma irradiation and lipid extraction were low: 2.4% and 2.5%, respectively, for ultrasound propagation wave measurements. They were clearly significant for protocol including 6M urea, corresponding to a loss of 30% in values measured in the control sample for the stress to failure, inciting prudence when grafted bone is used for support in orthopedic assembly. High consistency in the results obtained between travel time of the ultrasound wave, easily done, and measurement of stress to failure through conventional tests, favor the use of ultrasound protocol, described as a quality test performed on bone grafts in the tissue bank before distribution and implantation. PMID:14741625

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

    PubMed

    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. PMID:24678514

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

    PubMed Central

    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

  12. Distribution of Young's modulus in the cancellous bone of the proximal canine tibia.

    PubMed

    Sumner, D R; Willke, T L; Berzins, A; Turner, T M

    1994-08-01

    Canine cancellous bone is used as a model for human bone in experimental orthopedic research, including models of total knee arthroplasty. Depth-force measurements produced by small-diameter indentation testing were used to derive the variation of Young's modulus over the transverse cross-sectional surface at three levels within the proximal canine tibia. At the most proximal section the presence of lateral and medial peaks of equal modulus (approximately 1100 MPa) was found. Modulus averages for the three resection levels revealed a trend of distally decreasing values, from 692 MPa proximally to 417 MPa distally. Average regional modulus values for the canine tibia were 50-75% higher than previously reported for the tibia of healthy young adult humans, although the local maxima were only 5-20% greater in canines.

  13. Determining attenuation properties of interfering fast and slow ultrasonic waves in cancellous bone

    PubMed Central

    Nelson, Amber M.; Hoffman, Joseph J.; Anderson, Christian C.; Holland, Mark R.; Nagatani, Yoshiki; Mizuno, Katsunori; Matsukawa, Mami; Miller, James G.

    2011-01-01

    Previous studies have shown that interference between fast waves and slow waves can lead to observed negative dispersion in cancellous bone. In this study, the effects of overlapping fast and slow waves on measurements of the apparent attenuation as a function of propagation distance are investigated along with methods of analysis used to determine the attenuation properties. Two methods are applied to simulated data that were generated based on experimentally acquired signals taken from a bovine specimen. The first method uses a time-domain approach that was dictated by constraints imposed by the partial overlap of fast and slow waves. The second method uses a frequency-domain log-spectral subtraction technique on the separated fast and slow waves. Applying the time-domain analysis to the broadband data yields apparent attenuation behavior that is larger in the early stages of propagation and decreases as the wave travels deeper. In contrast, performing frequency-domain analysis on the separated fast waves and slow waves results in attenuation coefficients that are independent of propagation distance. Results suggest that features arising from the analysis of overlapping two-mode data may represent an alternate explanation for the previously reported apparent dependence on propagation distance of the attenuation coefficient of cancellous bone. PMID:21973378

  14. Fractal dimension predicts broadband ultrasound attenuation in stereolithography models of cancellous bone

    NASA Astrophysics Data System (ADS)

    Langton, C. M.; Whitehead, M. A.; Haire, T. J.; Hodgskinson, R.

    1998-02-01

    There has been considerable debate on the relative dependence of broadband ultrasound attenuation (nBUA, ) upon the density and structure of cancellous bone. A nonlinear relationship between nBUA and porosity has recently been demonstrated using stereolithography models, indicating a high structural dependence for nBUA. We report here on the measurement of trabecular perimeter and fractal dimension on the two-dimensional images used to create the stereolithography models. Adjusted coefficients of determination with nBUA were 94.4% and 98.4% for trabecular perimeter and fractal dimension respectively. The feature of fractal dimension representing both the porosity and connectivity of a given structure is most exciting. Further work is required to determine the relationship between broadband ultrasound attenuation and fractal dimension in complex three-dimensional cancellous bone structures.

  15. Determining attenuation properties of interfering fast and slow ultrasonic waves in cancellous bone.

    PubMed

    Nelson, Amber M; Hoffman, Joseph J; Anderson, Christian C; Holland, Mark R; Nagatani, Yoshiki; Mizuno, Katsunori; Matsukawa, Mami; Miller, James G

    2011-10-01

    Previous studies have shown that interference between fast waves and slow waves can lead to observed negative dispersion in cancellous bone. In this study, the effects of overlapping fast and slow waves on measurements of the apparent attenuation as a function of propagation distance are investigated along with methods of analysis used to determine the attenuation properties. Two methods are applied to simulated data that were generated based on experimentally acquired signals taken from a bovine specimen. The first method uses a time-domain approach that was dictated by constraints imposed by the partial overlap of fast and slow waves. The second method uses a frequency-domain log-spectral subtraction technique on the separated fast and slow waves. Applying the time-domain analysis to the broadband data yields apparent attenuation behavior that is larger in the early stages of propagation and decreases as the wave travels deeper. In contrast, performing frequency-domain analysis on the separated fast waves and slow waves results in attenuation coefficients that are independent of propagation distance. Results suggest that features arising from the analysis of overlapping two-mode data may represent an alternate explanation for the previously reported apparent dependence on propagation distance of the attenuation coefficient of cancellous bone.

  16. Glycation of human cortical and cancellous bone captures differences in the formation of Maillard reaction products between glucose and ribose.

    PubMed

    Sroga, Grażyna E; Siddula, Alankrita; Vashishth, Deepak

    2015-01-01

    To better understand some aspects of bone matrix glycation, we used an in vitro glycation approach. Within two weeks, our glycation procedures led to the formation of advanced glycation end products (AGEs) at the levels that corresponded to approx. 25-30 years of the natural in vivo glycation. Cortical and cancellous bones from human tibias were glycated in vitro using either glucose (glucosylation) or ribose (ribosylation). Both glucosylation and ribosylation led to the formation of higher levels of AGEs and pentosidine (PEN) in cancellous than cortical bone dissected from all tested donors (young, middle-age and elderly men and women). More efficient glycation of bone matrix proteins in cancellous bone most likely depended on the higher porosity of this tissue, which facilitated better accessibility of the sugars to the matrix proteins. Notably, glycation of cortical bone from older donors led to much higher AGEs levels as compared to young donors. Such efficient in vitro glycation of older cortical bone could result from aging-related increase in porosity caused by the loss of mineral content. In addition, more pronounced glycation in vivo would be driven by elevated oxidation processes. Interestingly, the levels of PEN formation differed pronouncedly between glucosylation and ribosylation. Ribosylation generated very high levels of PEN (approx. 6- vs. 2.5-fold higher PEN level than in glucosylated samples). Kinetic studies of AGEs and PEN formation in human cortical and cancellous bone matrix confirmed higher accumulation of fluorescent crosslinks for ribosylation. Our results suggest that in vitro glycation of bone using glucose leads to the formation of lower levels of AGEs including PEN, whereas ribosylation appears to support a pathway toward PEN formation. Our studies may help to understand differences in the progression of bone pathologies related to protein glycation by different sugars, and raise awareness for excessive sugar supplementation in food and

  17. Novel methodology for assessing biomaterial-biofluid interaction in cancellous bone.

    PubMed

    Bou-Francis, Antony; Widmer Soyka, René P; Ferguson, Stephen J; Hall, Richard M; Kapur, Nikil

    2015-06-01

    Understanding the cement flow behaviour and accurately predicting the cement placement within the vertebral body is extremely challenging. Vertebral cancellous bone displays highly complex geometrical structures and architectural inhomogeneities over a range of length scales, thus making the scientific understanding of the cement injection behaviour difficult in clinical or cadaveric studies. Previous experimental studies on cement flow have used open-porous aluminum foam to represent osteoporotic bone. Although the porosity was well controlled, the geometrical structure of each of the foams was inherently unique. This paper presents novel methodology using customized, reproducible and pathologically representative three-dimensional bone surrogates to help study biomaterial--biofluid interaction. The aim was to provide a robust tool for comprehensive assessment of biomaterial injection behaviour through controlling the bone surrogate morphology and the injection parameters (i.e. needle gauge, needle placement, flow rate and injected volume), measuring the injection pressure, and allowing the visualization and quantitative analysis of the spreading distribution. This methodology provides a clinically relevant representation of cement flow patterns and a tool for validating computational simulations.

  18. Comparison of alendronate and sodium fluoride effects on cancellous and cortical bone in minipigs. A one-year study.

    PubMed Central

    Lafage, M H; Balena, R; Battle, M A; Shea, M; Seedor, J G; Klein, H; Hayes, W C; Rodan, G A

    1995-01-01

    Fluoride stimulates trabecular bone formation, whereas bisphosphonates reduce bone resorption and turnover. Fracture prevention has not been convincingly demonstrated for either treatment so far. We compared the effects of 1-yr treatment of 9-mo-old minipigs with sodium fluoride (NaF, 2 mg/kg/d p.o.) or alendronate (ALN, 4 amino-1-hydroxybutylidene bisphosphonate monosodium, 1 mg/kg/d p.o.) on the biomechanical and histomorphometric properties of pig bones. As expected, NaF increased and ALN decreased bone turnover, but in these normal animals neither changed mean bone volume. NaF reduced the strength of cancellous bone from the L4 vertebra, relative to control animals, and the stiffness (resistance to deformation) of the femora, relative to the ALN group. In the ALN-treated animals, there was a strong positive correlation between bone strength and L5 cancellous bone volume, but no such correlation was observed in the NaF group. Furthermore, the modulus (resistance to deformation of the tissue) was inversely related to NaF content and there was a relative decrease in bone strength above 0.25 mg NaF/g bone. Moreover, within the range of changes measured in this study, there was an inverse correlation between bone turnover, estimated as the percentage of osteoid surface, and modulus. These findings have relevant implications regarding the use of these agents for osteoporosis therapy. PMID:7738180

  19. Beta-1 adrenergic agonist treatment mitigates negative changes in cancellous bone microarchitecture and inhibits osteocyte apoptosis during disuse.

    PubMed

    Swift, Joshua M; Swift, Sibyl N; Allen, Matthew R; Bloomfield, Susan A

    2014-01-01

    The sympathetic nervous system (SNS) plays an important role in mediating bone remodeling. However, the exact role that beta-1 adrenergic receptors (beta1AR) have in this process has not been elucidated. We have previously demonstrated the ability of dobutamine (DOB), primarily a beta1AR agonist, to inhibit reductions in cancellous bone formation and mitigate disuse-induced loss of bone mass. The purpose of this study was to characterize the independent and combined effects of DOB and hindlimb unloading (HU) on cancellous bone microarchitecture, tissue-level bone cell activity, and osteocyte apoptosis. Male Sprague-Dawley rats, aged 6-mos, were assigned to either normal cage activity (CC) or HU (n = 18/group) for 28 days. Animals were administered either daily DOB (4 mg/kg BW/d) or an equal volume of saline (VEH) (n = 9/gp). Unloading resulted in significantly lower distal femur cancellous BV/TV (-33%), Tb.Th (-11%), and Tb.N (-25%) compared to ambulatory controls (CC-VEH). DOB treatment during HU attenuated these changes in cancellous bone microarchitecture, resulting in greater BV/TV (+29%), Tb.Th (+7%), and Tb.N (+21%) vs. HU-VEH. Distal femur cancellous vBMD (+11%) and total BMC (+8%) were significantly greater in DOB- vs. VEH-treated unloaded rats. Administration of DOB during HU resulted in significantly greater osteoid surface (+158%) and osteoblast surface (+110%) vs. HU-VEH group. Furthermore, Oc.S/BS was significantly greater in HU-DOB (+55%) vs. CC-DOB group. DOB treatment during unloading fully restored bone formation, resulting in significantly greater bone formation rate (+200%) than in HU-VEH rats. HU resulted in an increased percentage of apoptotic cancellous osteocytes (+85%), reduced osteocyte number (-16%), lower percentage of occupied osteocytic lacunae (-30%) as compared to CC-VEH, these parameters were all normalized with DOB treatment. Altogether, these data indicate that beta1AR agonist treatment during disuse mitigates negative

  20. Evidence for reduced cancellous bone mass in the spontaneously hypertensive rat

    NASA Technical Reports Server (NTRS)

    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.

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

    PubMed

    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.

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

    PubMed

    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. PMID:20883832

  3. Experimental study of cancellous bone under large strains and a constitutive probabilistic model.

    PubMed

    Kefalas, V; Eftaxiopoulos, D A

    2012-02-01

    Experimental study of bovine cancellous bone up to compaction under uniaxial compression and up to fracture under tension, has been pursued in this article. Compression experiments have revealed the known three stages of the constitutive response, namely the initial increasing and softening branches at moderate strains, the plateau region at large strains and the hardening part at very large strains under compaction. Tension tests have quantified the increasing and softening branches of the stress-strain curve up to fracture. Subsequently, a constitutive mechanical model, for the simulation of the experimental findings up to very large strains (75% engineering strain under compression), is proposed. The model is based on the statistical description of (a) the failure process of the trabecular structure at small and moderate strains and (b) the compaction process of the trabecular mass at very large strains under compression. Several fitting cases indicated that the presented constitutive law can capture the evolution of the experimental results. PMID:22301172

  4. Effects of sodium hydroxide, sodium hypochlorite, and gaseous hydrogen peroxide on the natural properties of cancellous bone.

    PubMed

    Bi, Long; Li, De-Cheng; Huang, Zhao-Song; Yuan, Zhi

    2013-07-01

    Processed xenegeneic cancellous bone represents an alternative to bone autograft. In order to observe the effects of present prion inactivation treatments on the natural properties of xenogeneic cancellous bones, we treated bovine bone granules with sodium hydroxide (NaOH), sodium hypochlorite (NaOCl), and gaseous hydrogen peroxide (gH2 O2 ) respectively in this study. The microstructure, composition, and mineral content of the granules were evaluated by scanning electron micrograph, energy dispersive X-ray spectroscopy, ash analysis, and micro-computed tomography. The biomechanical property was analyzed by a materials testing machine. The cytocompatibility was evaluated by using a mouse fibroblast cell line (3T3). The microstructure, organic content, and mechanical strength were dramatically altered at the surface of bone in both NaOH- and NaOCl-treated groups, but not in the gH2 O2 -treated group. Compared with the gH2 O2 -treated group, attachment and proliferation of 3T3 were reduced in either NaOH- or NaOCl-treated groups. As the consequence, gH2 O2 treatment may be a useful approach of disinfection for the preparation of natural cancellous bone with well-preserved structural, mechanical, and biological properties.

  5. Bone Related Health Status in Adolescent Cyclists

    PubMed Central

    Olmedillas, Hugo; González-Agüero, Alejandro; Moreno, Luís A.; Casajús, José A.; Vicente-Rodríguez, Germán

    2011-01-01

    Purpose To describe bone status and analyse bone mass in adolescent cyclists. Methods Male road cyclists (n = 22) who had been training for a minimum of 2 years and a maximum of 7 years with a volume of 10 h/w, were compared to age-matched controls (n = 22) involved in recreational sports activities. Subjects were divided in 2 groups based on age: adolescents under 17 yrs (cyclists, n = 11; controls, n = 13) and over 17 yrs (cyclists, n = 11; controls, n = 9). Peak oxygen uptake (VO2max) was measured on a cycloergometer. Whole body, lumbar spine, and hip bone mineral content (BMC), density (BMD) and bone area were assessed using dual x-ray absorptiometry (DXA). Volumetric BMD (vBMD) and bone mineral apparent density (BMAD) were also estimated. Results The BMC of cyclists was lower for the whole body, pelvis, femoral neck and legs; BMD for the pelvis, hip, legs and whole body and legs bone area was lower but higher in the hip area (all, P≤0.05) after adjusting by lean mass and height. The BMC of young cyclists was 10% lower in the leg and 8% higher in the hip area than young controls (P≤0.05). The BMC of cyclists over 17 yrs was 26.5%, 15.8% and 14.4% lower BMC at the pelvis, femoral neck and legs respectively while the BMD was 8.9% to 24.5% lower for the whole body, pelvis, total hip, trochanter, intertrochanter, femoral neck and legs and 17.1% lower the vBMD at the femoral neck (all P≤0.05). Grouped by age interaction was found in both pelvis and hip BMC and BMD and in femoral neck vBMD (all P≤0.05). Conclusion Cycling performed throughout adolescence may negatively affect bone health, then compromising the acquisition of peak bone mass. PMID:21980360

  6. Muscle Power Predicts Adolescent Bone Strength: Iowa Bone Development Study

    PubMed Central

    Janz, Kathleen F.; Letuchy, Elena M.; Burns, Trudy L.; Francis, Shelby L.; Levy, Steven M.

    2015-01-01

    Purpose To assess association between lower body muscle power and bone strength, as well as the mediating effect of muscle cross-sectional area (MCSA) on that association. Methods Participants (N=141 males; 162 females) were approximately 17 years. Muscle power was predicted using vertical jump and the Sayers equation. Using peripheral quantitative computed tomography (pQCT), bone strength indices were obtained at two locations of the tibia, corresponding to primary stressors acting upon each site: bone strength index for compression (BSI) at the distal 4% site; density-weighted polar section modulus strength-strain index [SSIp] and cortical bone area (CoA) at the 66% mid-shaft site for torsion. Muscle cross-sectional area (MCSA) was measured at the 66% site. Pearson bivariate and partial correlation coefficients were estimated to quantify the strength of the associations among variables. Direct and indirect mediation model effects were estimated and 95% bootstrap confidence intervals were constructed to test the causal hypothesis. Height and maturity were examined as covariates. Results Pearson correlation coefficients among muscle power, MCSA, and bone strength were statistically significant (p<0.01) and ranged from r=0.54 to 0.78. After adjustment for covariates, associations were reduced (r=0.37 to 0.69) (p<0.01). Mediation models for males for BSI, SSIp, and CoA accounted for 38%, 66%, and 54% of the variance in bone strength, respectively. Models for females for BSI, SSIp, and CoA accounted for 46%, 77%, and 66% of the variance, respectively. Conclusions We found strong and consistent associations, as well as direct and indirect pathways, among muscle power, MCSA, and tibia strength. These results support the use of muscle power as a component of health-related fitness in bone health interventions for older adolescents. PMID:25751769

  7. Does peripheral quantitative computed tomography ignore tissue density of cancellous bone?

    PubMed

    Banse, X; Devogelaer, J P

    2002-01-01

    The purpose of this work was to determine the capacity of peripheral quantitative computed tomography (pQCT) to accurately measure the true physical properties of vertebral cancellous bone samples and to predict their stiffness. pQCT bone mineral density (BMD) was first measured in ideal conditions. Ten cubic specimens of vertebral cancellous bone (10 x 10 x 10 mm) were washed with a water jet, defatted, and scanned in saline after elimination of air bubbles; thirteen slices were obtained. Seventy-one unprepared cylindrical samples were scanned in more realistic conditions, which allow further biomechanical testing. After extraction from the vertebral body, the samples were pushed into a plastic tube (no effort was made to remove the marrow or air bubbles), and only four slices were obtained to reduce the duration of scan. For the 81 samples, the true bone volume fraction (BV/TV, %), true apparent density (rho(app), g/cm(3)), and tissue density (rho(tiss), g/cm(3)) (an indicator of the degree of mineralization of the matrix) were then measured using Archimedes principle. rho(app) was closely correlated to BV/TV (r(2) = 0.97). rho(tiss) (1.58 +/- 0.08 g/cm(2)) was almost constant but had some influence on rho(app) (r(2) = 0.03, p < 0.001). The pQCT BMD predicted accurately rho(app) (r(2) = 0.96) and BV/TV (r(2) = 0.93) for the cylinders. For the cubes, in ideal conditions, the same correlations were even better (r(2) > 0.99, both). Analysis of covariance indicated no difference (p > 0.05) in the regressions due to preparation of the samples. The stiffness was better predicted by the true rho(app) (r(2) = 0.87) than by BV/TV (r(2) = 0.83), indicating that stiffness was influenced by small differences in the tissue density. Consequently, the correlation between pQCT BMD and stiffness was excellent (r(2) = 0.84). The fact that pQCT did not ignore this tissue density information compensated for the inaccuracies linked to realistic scanning conditions of the cylinder

  8. Effects of phase cancellation and receiver aperture size on broadband ultrasonic attenuation for trabecular bone in vitro.

    PubMed

    Cheng, Jiqi; Serra-Hsu, Frederick; Tian, Yuan; Lin, Wei; Qin, Yi-Xian

    2011-12-01

    Phase cancellation in ultrasound due to large receiver size has been proposed as a contributing factor to the inaccuracy of estimating broadband ultrasound attenuation (BUA), which is used to characterize bone quality. Transducers with aperture size ranging from 2 to 5 mm have been used in previous attempts to study the effect of phase cancellation. However, these receivers themselves are susceptible to phase cancellation because aperture size is close to one center wavelength (about 3 mm at 500 KHz in water). This study uses an ultra small receiver (aperture size: 0.2 mm) in conjunction with a newly developed two-dimensional (2-D) synthetic array system to investigate the effects of phase cancellation and receiver aperture size on BUA estimations of bone tissue. In vitro ultrasound measurements were conducted on 54 trabecular bone samples (harvested from sheep femurs) in a confocal configuration with a focused transmitter and synthesized focused receivers of different aperture sizes. Phase sensitive (PS) and phase insensitive (PI) detections were performed. The results show that phase cancellation does have a significant effect on BUA. The normalized BUA (nBUA) with PS is 8.1% higher than PI nBUA while PI BUA is well correlated with PS BUA. Receiver aperture size also influences the BUA reading for both PI and PS detection and smaller receiver aperture tends to result in higher BUA readings. The results also indicate that the receiver aperture size used in the confocal configuration with PI detection should at least equal the aperture of the transmitter to capture most of the energy redistributed by the interference and diffraction from the trabecular bone.

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Bone mineral density in elite adolescent female figure skaters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elite adolescent figure skaters must accommodate both the physical demands of competitive training and the accelerated rate of bone growth that is associated with adolescence. Although, these athletes apparently undergo sufficient physical activity to develop healthy bones, it is possible that other...

  11. Anisotropic post-yield response of cancellous bone simulated by stress-strain curves of bulk equivalent structures.

    PubMed

    Tsouknidas, Alexander; Maliaris, Georgios; Savvakis, Savvas; Michailidis, Nikolaos

    2015-01-01

    During the last decade, finite element (FE) modelling has become ubiquitous in understanding complex mechanobiological phenomena, e.g. bone-implant interactions. The extensive computational effort required to achieve biorealistic results when modelling the post-yield behaviour of microstructures like cancellous bone is a major limitation of these techniques. This study describes the anisotropic biomechanical response of cancellous bone through stress-strain curves of equivalent bulk geometries. A cancellous bone segment, reverse engineered by micro computed tomography, was subjected to uniaxial compression. The material's constitutive law, obtained by nano-indentations, was considered during the simulation of the experimental process. A homodimensionally bulk geometry was employed to determine equivalent properties, resulting in a similar anisotropic response to the trabecular structure. The experimental verification of our model sustained that the obtained stress-strain curves can adequately reflect the post-yield behaviour of the sample. The introduced approach facilitates the consideration of nonlinearity and anisotropy of the tissue, while reducing the geometrical complexity of the model to a minimum. PMID:24156688

  12. Anisotropic post-yield response of cancellous bone simulated by stress-strain curves of bulk equivalent structures.

    PubMed

    Tsouknidas, Alexander; Maliaris, Georgios; Savvakis, Savvas; Michailidis, Nikolaos

    2015-01-01

    During the last decade, finite element (FE) modelling has become ubiquitous in understanding complex mechanobiological phenomena, e.g. bone-implant interactions. The extensive computational effort required to achieve biorealistic results when modelling the post-yield behaviour of microstructures like cancellous bone is a major limitation of these techniques. This study describes the anisotropic biomechanical response of cancellous bone through stress-strain curves of equivalent bulk geometries. A cancellous bone segment, reverse engineered by micro computed tomography, was subjected to uniaxial compression. The material's constitutive law, obtained by nano-indentations, was considered during the simulation of the experimental process. A homodimensionally bulk geometry was employed to determine equivalent properties, resulting in a similar anisotropic response to the trabecular structure. The experimental verification of our model sustained that the obtained stress-strain curves can adequately reflect the post-yield behaviour of the sample. The introduced approach facilitates the consideration of nonlinearity and anisotropy of the tissue, while reducing the geometrical complexity of the model to a minimum.

  13. Socket preservation and sinus augmentation using a medical grade calcium sulfate hemihydrate and mineralized irradiated cancellous bone allograft composite.

    PubMed

    Bagoff, Robert; Mamidwar, Sachin; Chesnoiu-Matei, Ioana; Ricci, John L; Alexander, Harold; Tovar, Nick M

    2013-06-01

    Regeneration and preservation of bone after the extraction of a tooth are necessary for the placement of a dental implant. The goal is to regenerate alveolar bone with minimal postoperative pain. Medical grade calcium sulfate hemihydrate (MGCSH) can be used alone or in combination with other bone grafts; it improves graft handling characteristics and particle containment of particle-based bone grafts. In this case series, a 1:1 ratio mix of MGCSH and mineralized irradiated cancellous bone allograft (MICBA) was mixed with saline and grafted into an extraction socket in an effort to maintain alveolar height and width for future implant placement. MGCSH can be used in combination with other bone grafts and can improve handling characteristics and graft particle containment of particle-based bone grafts. In the cases described, we found that an MGCSH:MICBA graft can potentially be an effective bone graft composite. It has the ability to act as a space maintainer and as an osteoconductive trellis for bone cells, thereby promoting bone regeneration in the extraction socket. MGCSH, a cost-effective option, successfully improved MICBA handling characteristics, prevented soft tissue ingrowth, and assisted in the regeneration of bone.

  14. Anatomically safe and minimally invasive transcrestal technique for procurement of autogenous cancellous bone graft from the mid-iliac crest

    PubMed Central

    Missiuna, Paul C.; Gandhi, Harjeet S.; Farrokhyar, Forough; Harnett, Barry E.; Dore, Edward M.G.; Roberts, Barbara

    2011-01-01

    Background Open iliac bone harvesting techniques can result in significant complications and residual morbidity. In reconstructive procedures where a small volume of autogenous cancellous bone graft is required, a minimally invasive technique for bone harvesting applied at the mid-iliac crest has been deemed satisfactory. We sought to assess the application of a well-established surgical technique to procure adequate volume of autogenous cancellous iliac bone graft with minimal trauma to adjacent structures. Methods We retrospectively reviewed the cases of patients who underwent a minimally invasive transcrestal mid-iliac bone graft procurement technique between May 2003 and December 2007. The technique was performed using a 3.5-mm Steinmann pin as a trocar and a 4.5-mm AO drill sleeve as a trephine. We administered a questionnaire, either in the clinic or by mail, to assess a number of parameters, including postoperative pain, dysthesia, parasthesia, status of the donor site wound and patient satisfaction. Results Of the 37 consecutive patients who underwent the procedure, data from 26 patients were available for assessment. Donor site pain resolved within a few days of the surgery, and none of the patients experienced symptoms of chronic pain. At the final review, none of the patients reported any unpleasant signs and symptoms related to the residual scar. Conclusion We recommend that the described minimally invasive trephine method be used when a small cancellous bone graft is needed. We found that patient morbidity was significantly lower with the trephine harvest technique than with open bone harvesting methods at the anterior iliac crest. PMID:21933526

  15. Histomorphometric Assessment of Cancellous and Cortical Bone Material Distribution in the Proximal Humerus of Normal and Osteoporotic Individuals

    PubMed Central

    Sprecher, Christoph M.; Schmidutz, Florian; Helfen, Tobias; Richards, R. Geoff; Blauth, Michael; Milz, Stefan

    2015-01-01

    Abstract Osteoporosis is a systemic disorder predominantly affecting postmenopausal women but also men at an advanced age. Both genders may suffer from low-energy fractures of, for example, the proximal humerus when reduction of the bone stock or/and quality has occurred. The aim of the current study was to compare the amount of bone in typical fracture zones of the proximal humerus in osteoporotic and non-osteoporotic individuals. The amount of bone in the proximal humerus was determined histomorphometrically in frontal plane sections. The donor bones were allocated to normal and osteoporotic groups using the T-score from distal radius DXA measurements of the same extremities. The T-score evaluation was done according to WHO criteria. Regional thickness of the subchondral plate and the metaphyseal cortical bone were measured using interactive image analysis. At all measured locations the amount of cancellous bone was significantly lower in individuals from the osteoporotic group compared to the non-osteoporotic one. The osteoporotic group showed more significant differences between regions of the same bone than the non-osteoporotic group. In both groups the subchondral cancellous bone and the subchondral plate were least affected by bone loss. In contrast, the medial metaphyseal region in the osteoporotic group exhibited higher bone loss in comparison to the lateral side. This observation may explain prevailing fracture patterns, which frequently involve compression fractures and certainly has an influence on the stability of implants placed in this medial region. It should be considered when planning the anchoring of osteosynthesis materials in osteoporotic patients with fractures of the proximal humerus. PMID:26705200

  16. Age-related differences in microstructure, density and biomechanics of vertebral cancellous bone of Chinese males.

    PubMed

    Liu, Guo-Min; Xu, Chuan-Jie; Kong, Ning; Zhu, Xiao-Min; Zhang, Xing-Yi; Yao, Yan

    2012-12-01

    The conventional lumbar separation was performed by removing soft tissue, subsidiary structures and leaving only the vertebral body. The vertebral body was cut into two halves along the median sagittal plane, keeping the upper and lower end plates of each half, which were subsequently used for biomechanical, morphological and density experiments. From the age of 20-29 to 30-39 years, both the horizontal trabecular thickness (Tb.Th) and vertical Tb.Th decreased; the horizontal and vertical Tb.Sp increased; the plate-like trabecular Tb.Th decreased; the apparent density and volume ratio decreased; and the elastic modulus and the ultimate stress decreased; with all changes being statistically significant (p < 0.01). Similar trends were obtained from ages 40-49 to 50-59, although the changes were not significant (p > 0.05), except for the reduction in ultimate stress (p < 0.05). With aging, the collagen cross-linking capacity declined; the thicknesses of the collagen fibrils were variable, ranging from almost the same to loose, sparse or disordered thickness; and the finer collagen fibrils between the thick filaments were disorganized. In males aged from 20 to 59 years old, the horizontal and vertical Tb.Th and the plate-like Tb.Th of the vertebral body decreased, while the horizontal and vertical Tb.Sp increased. Additionally, the density, elastic modulus and the ultimate stress of the cancellous bone decreased with age. Thus, the associated changes of bone microstructure, density and biomechanics with age may lead to an increased risk of osteoporosis and fracture.

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

    PubMed

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

    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. PMID:27524040

  18. Conventional, Bayesian, and Modified Prony's methods for characterizing fast and slow waves in equine cancellous bone

    PubMed Central

    Groopman, Amber M.; Katz, Jonathan I.; Holland, Mark R.; Fujita, Fuminori; Matsukawa, Mami; Mizuno, Katsunori; Wear, Keith A.; Miller, James G.

    2015-01-01

    Conventional, Bayesian, and the modified least-squares Prony's plus curve-fitting (MLSP + CF) methods were applied to data acquired using 1 MHz center frequency, broadband transducers on a single equine cancellous bone specimen that was systematically shortened from 11.8 mm down to 0.5 mm for a total of 24 sample thicknesses. Due to overlapping fast and slow waves, conventional analysis methods were restricted to data from sample thicknesses ranging from 11.8 mm to 6.0 mm. In contrast, Bayesian and MLSP + CF methods successfully separated fast and slow waves and provided reliable estimates of the ultrasonic properties of fast and slow waves for sample thicknesses ranging from 11.8 mm down to 3.5 mm. Comparisons of the three methods were carried out for phase velocity at the center frequency and the slope of the attenuation coefficient for the fast and slow waves. Good agreement among the three methods was also observed for average signal loss at the center frequency. The Bayesian and MLSP + CF approaches were able to separate the fast and slow waves and provide good estimates of the fast and slow wave properties even when the two wave modes overlapped in both time and frequency domains making conventional analysis methods unreliable. PMID:26328678

  19. Conventional, Bayesian, and Modified Prony's methods for characterizing fast and slow waves in equine cancellous bone.

    PubMed

    Groopman, Amber M; Katz, Jonathan I; Holland, Mark R; Fujita, Fuminori; Matsukawa, Mami; Mizuno, Katsunori; Wear, Keith A; Miller, James G

    2015-08-01

    Conventional, Bayesian, and the modified least-squares Prony's plus curve-fitting (MLSP + CF) methods were applied to data acquired using 1 MHz center frequency, broadband transducers on a single equine cancellous bone specimen that was systematically shortened from 11.8 mm down to 0.5 mm for a total of 24 sample thicknesses. Due to overlapping fast and slow waves, conventional analysis methods were restricted to data from sample thicknesses ranging from 11.8 mm to 6.0 mm. In contrast, Bayesian and MLSP + CF methods successfully separated fast and slow waves and provided reliable estimates of the ultrasonic properties of fast and slow waves for sample thicknesses ranging from 11.8 mm down to 3.5 mm. Comparisons of the three methods were carried out for phase velocity at the center frequency and the slope of the attenuation coefficient for the fast and slow waves. Good agreement among the three methods was also observed for average signal loss at the center frequency. The Bayesian and MLSP + CF approaches were able to separate the fast and slow waves and provide good estimates of the fast and slow wave properties even when the two wave modes overlapped in both time and frequency domains making conventional analysis methods unreliable.

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

    PubMed

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

    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.

  1. Osteoblast-specific overexpression of amphiregulin leads to transient increase in femoral cancellous bone mass in mice.

    PubMed

    Vaidya, Mithila; Lehner, Diana; Handschuh, Stephan; Jay, Freya F; Erben, Reinhold G; Schneider, Marlon R

    2015-12-01

    The epidermal growth factor receptor ligand amphiregulin (AREG) has been implicated in bone physiology and in bone anabolism mediated by intermittent parathyroid hormone treatment. However, the functions of AREG in bone have been only incipiently evaluated in vivo. Here, we generated transgenic mice overexpressing AREG specifically in osteoblasts (Col1-Areg). pQCT analysis of the femoral metaphysis revealed increased trabecular bone mass at 4, 8, and 10weeks of age in Col1-Areg mice compared to control littermates. However, the high bone mass phenotype was transient and disappeared in older animals. Micro-CT analysis of the secondary spongiosa confirmed increased trabecular bone volume and trabecular number in the distal femur of 4-week-old AREG-tg mice compared to control littermates. Furthermore, μ-CT analysis of the primary spongiosa revealed unaltered production of new bone trabeculae in distal femora of Col1-Areg mice. Histomorphometric analysis revealed a reduced number of osteoclasts in 4-week-old Col1-Areg mice, but not at later time points. Cancellous bone formation rate remained unchanged in Col1-Areg mice at all time points. In addition, bone mass and bone turnover in lumbar vertebral bodies were similar in Col1-Areg and control mice at all ages examined. Proliferation and differentiation of osteoblasts isolated from neonatal calvariae did not differ between Col1-Areg and control mice. Taken together, these data suggest that AREG overexpression in osteoblasts induces a transient high bone mass phenotype in the trabecular compartment of the appendicular skeleton by a growth-related, non-cell autonomous mechanism, leading to a positive bone balance with unchanged bone formation and lowered bone resorption.

  2. Human parathyroid hormone-(1-38) restores cancellous bone to the immobilized, osteopenic proximal tibial metaphysis in rats

    NASA Technical Reports Server (NTRS)

    Ma, Y. F.; Jee, W. S.; Ke, H. Z.; Lin, B. Y.; Liang, X. G.; Li, M.; Yamamoto, N.

    1995-01-01

    The purpose of this study was to determine if human parathyroid hormone-(1-38) (hPTH(1-38)) can restore cancellous bone mass to the established osteopenic, immobilized proximal tibial metaphyses of female rats. The right hindlimbs of 6-month-old female Sprague-Dawley rats were immobilized by bandaging the right hindlimbs to the abdomen. After 30 days of right hindlimb immobilization, the rats were subcutaneously injected with 200 micrograms hPTH(1-38)/kg/day for 15 days (short-term treatment) or 75 days (longer-term treatment). Static bone histomorphometry was performed on the primary spongiosa, and both static and dynamic histomorphometry were performed on the secondary spongiosa of the right proximal tibial metaphyses. Immobilization for 30 days without treatment decreased trabecular bone area, number, and thickness in both primary and secondary spongiosa, and induced an increase in eroded perimeter and a decrease in tissue referent-bone formation rate in the secondary spongiosa. These changes reached a new steady state thereafter. Treatment with 200 micrograms hPTH(1-38)/kg/day for 15 days, beginning 30 days after immobilization, significantly increased trabecular bone area, thickness, and number in both primary and secondary spongiosa despite continuous immobilization when compared with controls. The short-term PTH treatment (15 days) significantly increased labeling perimeter, mineral apposition rate, and tissue referent-bone formation rate in the secondary spongiosa and stimulated longitudinal bone growth as compared with the controls. Longer PTH treatment (75 days) further increased trabecular bone area, thickness, and number as compared with controls and groups given short-term PTH treatment (15 days). The bone formation indices in the secondary spongiosa of the longer-term treated rats were lower than those of the short-term treated group, but they were still higher than those of controls. Our findings indicate that PTH treatment stimulates cancellous bone

  3. Human parathyroid hormone-(1-38) restores cancellous bone to the immobilized, osteopenic proximal tibial metaphysis in rats

    NASA Technical Reports Server (NTRS)

    Ma, Y. F.; Jee, W. S. S.; Ke, H. Z.; Lin, B. Y.; Liang, X. G.; Li, M.; Yamamoto, N.

    1994-01-01

    The purpose of this study was to determine if human parathyroid hormone-(1-38) (PTH) can restore cancellous bone mass to the established osteopenic, immobilized proximal tibial metaphyses (PTM) of female rats. The right hindlimbs of six-month-old female Sprague-Dawley rats were immobilized by bandaging the right hindlimbs to the abdomen. After 30 days of right hindlimb immobilization (RHLI), the rats were subcutaneously injected with 200 microgram hPTH(1-38)/kg/day for 15 (short-term) or 75 (longer-term) days. Static bone histomorphometry was performed on the primary spongiosa, while both static and dynamic histomorphometry were performed on the secondary spongiosa of the right PTM. Immobilization for 30 days without treatment decreased trabecular bone area, number and thickness in both primary and secondary spongiosa, and induced an increase in eroded perimeter and a decrease in tissue referent-bone formation rate (BFR/TV) in the secondary spongios. These changes reached a new steady state thereafter. Treatment with 200 microgram hPTH(1-38)/kg/day for 15 days, beginning at 30 days post immobilization (IM), significantly increased trabecular bone area, thickness and number in both primary and secondary spongiosa despite continuous IM when compared to the age-related and IM controls. The short-term (15 days) PTH treatment significantly increased labeling perimeter, mineral apposition rate and BFR/TV in the secondary spongiosa and stimulated longitudinal bone growth as compared to the age-related and IM controls. PTH treatment for longer-term (75 days) further increased trabecular bone area, thickness and number as compared to aging and IM controls and short-term (15 days) PTH treated groups. The bone formation indices in the secondary spongiosa of these longer-term treated rats were lower than that of short-term (15 days) PTH treated group, but they were still higher than those of IM and age-related controls. Our findings indicate that PTH treatment stimulates

  4. Posterolateral Arthrodesis in Lumbar Spine Surgery Using Autologous Platelet-Rich Plasma and Cancellous Bone Substitute: An Osteoinductive and Osteoconductive Effect

    PubMed Central

    Tarantino, Roberto; Donnarumma, Pasquale; Mancarella, Cristina; Rullo, Marika; Ferrazza, Giancarlo; Barrella, Gianna; Martini, Sergio; Delfini, Roberto

    2014-01-01

    Study Design Prospective cohort study. Objectives To analyze the effectiveness and practicality of using cancellous bone substitute with platelet-rich plasma (PRP) in posterolateral arthrodesis. Methods Twenty consecutive patients underwent posterolateral arthrodesis with implantation of cancellous bone substitute soaked with PRP obtained directly in the operating theater on the right hemifield and cancellous bone substitute soaked with saline solution on the right. Results Computed tomography scans at 6 and 12 months after surgery were performed in all patients. Bone density was investigated by comparative analysis of region of interest. The data were analyzed with repeated-measures variance analyses with value of density after 6 months and value of density after 12 months, using age, levels of arthrodesis, and platelet count as covariates. The data demonstrated increased bone density using PRP and heterologous cancellous block resulting in an enhanced fusion rate during the first 6 months after surgery. Conclusions PRP used with cancellous bone substitute increases the rate of fusion and bone density joining osteoinductive and osteoconductive effect. PMID:25083353

  5. Posterolateral arthrodesis in lumbar spine surgery using autologous platelet-rich plasma and cancellous bone substitute: an osteoinductive and osteoconductive effect.

    PubMed

    Tarantino, Roberto; Donnarumma, Pasquale; Mancarella, Cristina; Rullo, Marika; Ferrazza, Giancarlo; Barrella, Gianna; Martini, Sergio; Delfini, Roberto

    2014-08-01

    Study Design Prospective cohort study. Objectives To analyze the effectiveness and practicality of using cancellous bone substitute with platelet-rich plasma (PRP) in posterolateral arthrodesis. Methods Twenty consecutive patients underwent posterolateral arthrodesis with implantation of cancellous bone substitute soaked with PRP obtained directly in the operating theater on the right hemifield and cancellous bone substitute soaked with saline solution on the right. Results Computed tomography scans at 6 and 12 months after surgery were performed in all patients. Bone density was investigated by comparative analysis of region of interest. The data were analyzed with repeated-measures variance analyses with value of density after 6 months and value of density after 12 months, using age, levels of arthrodesis, and platelet count as covariates. The data demonstrated increased bone density using PRP and heterologous cancellous block resulting in an enhanced fusion rate during the first 6 months after surgery. Conclusions PRP used with cancellous bone substitute increases the rate of fusion and bone density joining osteoinductive and osteoconductive effect.

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

    PubMed

    Diomede, F; Zini, N; Gatta, V; Fulle, S; Merciaro, I; D'Aurora, M; La Rovere, R M; Traini, T; Pizzicannella, J; Ballerini, P; Caputi, S; Piattelli, A; Trubiani, O

    2016-01-01

    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. PMID:27633707

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

    PubMed

    Ding, M; Odgaard, A; Hvid, I

    1999-03-01

    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 supplied algorithm (method I). A significant deviation of volume fraction from method I was found: both the y-intercept and the slope of the regression line were significantly different from those of the Archimedes-based volume fraction (p < 0.001). New individual thresholds were determined based on a calibration of volume fraction to the Archimedes-based volume fractions (method II). The mean thresholds of the two methods were applied to segment 20 randomly selected specimens. The results showed that volume fraction using the mean threshold of method I was underestimated by 4% (p = 0.001), whereas the mean threshold of method II yielded accurate values. The precision of the measurement was excellent. Our data show that care must be taken when applying thresholds in generating 3-D data, and that a fixed threshold may be used to obtain reliable volume fraction data. This fixed threshold may be determined from the Archimedes-based volume fraction of a subgroup of specimens. The threshold may vary between different materials, and so it should be determined whenever a study series is performed. PMID:10093033

  8. Effects of Chronic Heavy Alcohol Consumption and Endurance Exercise on Cancellous and Cortical Bone Microarchitecture in Adult Male Rats

    PubMed Central

    Johnson, Teresa L.; Gaddini, Gino; Branscum, Adam J.; Olson, Dawn A.; Caroline-Westerlind, Kim; Turner, Russell T.; Iwaniec, Urszula T.

    2014-01-01

    Background Bone health is influenced by numerous lifestyle factors, including diet and exercise. Alcohol is a major non-essential constituent of diet and has dose and context-dependent effects on bone. Endurance exercise is associated with increased risk for stress fractures. The purpose of this study was to determine the long-term independent and combined effects of chronic heavy alcohol consumption and endurance exercise (treadmill running) on bone mass and microarchitecture in young adult male Sprague-Dawley rats. Methods Six-month-old male rats were randomized into 4 groups (9–13 rats/group): sedentary+control diet, sedentary+ethanol diet, exercise+control diet, or exercise+ethanol diet. Ethanol-fed rats consumed a liquid diet (ethanol comprised 35% of caloric intake) ad libitum. Control rats were pair-fed the same diet with isocaloric substitution of ethanol with maltose-dextran. Exercise was conducted on a motorized treadmill (15% grade for 30 min) 5 days/week for 16 weeks. Femur and 12th thoracic vertebra were analyzed for bone mineral content (BMC) and density (BMD) using densitometry and cortical and cancellous bone architecture using microcomputed tomography. Results Ethanol consumption resulted in lower femur length, BMC, and BMD, and lower midshaft femur cortical volume, cortical thickness, and polar moment of inertia. In addition, trabecular thickness was lower in vertebra of ethanol-fed rats. Endurance exercise had no independent effect on any endpoints evaluated. A significant interaction between endurance exercise and ethanol was detected for several cancellous endpoints in the distal femur metaphysis. Ethanol-consuming rats that exercised had lower distal femur metaphysis bone volume/tissue volume, trabecular connectivity density, and trabecular thickness compared to exercising rats that consumed control diet. Conclusions The results obtained in this model suggest that chronic heavy alcohol consumption may reduce skeletal integrity by reducing

  9. DETERMINANTS OF BONE CALCIUM ACCRETION DURING EARLY ADOLESCENCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bone mineral status during adolescence may be related to genetic and dietary factors. We evaluated 49 female and 49 male adolescents (Tanner 2/3) randomized to receive 8g of Synergl (Orafti Inc., Belgium), a non-digestible inulin-type fructan daily for a year or placebo. Fractional calcium (Ca) abso...

  10. Revision hip arthroplasty using impacted cancellous bone and cement: a long-term follow-up study.

    PubMed

    Arumugam, Gowthaman; Nanjayan, Shashi Kumar; Quah, Conal; Wraighte, Philip; Howard, Peter

    2015-12-01

    Acetabular bone deficiency is one of the many challenging problems encountered in revision hip arthroplasty. A variety of surgical options and techniques are available including impaction bone grafting. We present our long-term experience of 68 consecutive cups in 64 patients, using impacted cancellous bone grafting with bone cement. With a mean follow-up of 10.5 year (IQR 7.5-12.9) after revision surgery, three implants had undergone further revision. Three patients had subsequent femoral peri-prosthetic fractures, and none of these three required further acetabular revision. Survival of the acetabular components was 95.5 % for all causes and 100 % for aseptic loosening as the end point, with a further four patients showing radiographic, but asymptomatic loosening. A significant correlation was found between previous revision and re-revision (early failure) (p = 0.01) as well as progression of lytic lesion and re-revision (p = 0.01). The median Harris hip score at final follow-up was 79.5 (IQR 67.9-80.4). The use of impacted morcellised allograft bone with a cemented cup is an effective technique to achieve longevity and restoration of bone stock in acetabular revision arthroplasty. Our series has shown good clinical and radiological outcome with survivorship of the prosthesis exceeding 95 % at 10 years.

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

    PubMed

    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 (p<0.05). The results of micro-CT showed that the bone 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 (p<0.05) respectively. The trabecular number showed the same downtrend (p<0.05). Histological analysis showed trabecular area/tissue area decreased by 32.1%, 23.2% and 20.7% in lumbar vertebrae, femoral necks and mandibular angles respectively (p<0.05), but no significant difference in ribs. Specimens elastic modulus from lumbar vertebra, femoral neck and mandibular angle were 952±76MPa (628±70MPa), 961±173MPa (610±72MPa) and 595±60MPa (444±31MPa) in control group (experimental group) respectively. These datum indicated that the sensibility of cancellous bones to oestrogen deficiency in ovariectomized sheep was site-specific on a pattern as follows: lumbar vertebra, femoral neck, mandibular angle and rib.

  12. Adolescent obesity, bone mass and cardiometabolic risk factors

    PubMed Central

    Pollock, Norman K; Bernard, Paul J; Gutin, Bernard; Davis, Catherine L; Zhu, Haidong; Dong, Yanbin

    2010-01-01

    Objective To compare bone mass between overweight adolescents with and without cardiometabolic risk factors (CMR). Associations of bone mass with CMR and adiposity were also determined. Study design Overweight adolescents (aged 14–18 years) were classified in Healthy (n=55), 1CMR (n=46) or ≥2CMR (n=42). CMR were measured using standard methods and defined according to pediatric definitions of metabolic syndrome. Total body bone mass, fat mass and fat-free soft tissue mass (FFST) were measured by DXA. Visceral adipose tissue (VAT) and subcutaneous abdominal adipose tissue (SAAT) were assessed using MRI. Results After controlling for age, sex, race, height and FFST, Healthy group had 5.4% and 6.3% greater bone mass than the 1CMR and ≥2CMR groups, respectively (both P<0.04). Multiple linear regression, adjusting for same covariates, revealed that VAT (β=−0.22), waist circumference (β= −0.23), homeostasis model assessment of insulin resistance (β= −0.23) and HDL-cholesterol (β=0.22) were associated with bone mass (all P<0.04). There was a trend towards a significant inverse association between bone mass and fasting glucose (P=0.056). No relations were found between bone mass and fat mass, SAAT, BP or triglycerides. Conclusion Being overweight with metabolic abnormalities, particularly insulin resistance, low HDL-cholesterol and visceral adiposity, may adversely influence adolescent bone mass. PMID:21232765

  13. Effects of alendronate and strontium ranelate on cancellous and cortical bone mass in glucocorticoid-treated adult rats.

    PubMed

    Sun, P; Cai, D H; Li, Q N; Chen, H; Deng, W M; He, L; Yang, L

    2010-06-01

    We studied the effects of alendronate (Aln) and strontium ranelate (SrR) administration on cancellous and cortical bone in glucocorticoid (GC)-treated rats. Thirty-two 3.5-month male Sprague-Dawley rats were randomized into four groups: age-matched normal control (Nrm), methylprednisolone (Met; 5.0 mg/kg/day, sc, for 5 days/week), Met plus Aln orally (1.0 mg/kg/day), and Met plus SrR orally (900 mg/kg/day). The study period was 9 weeks. DXA was used to evaluate the femoral diaphysis and fifth lumbar vertebra (L5). Histomorphometry was performed in the proximal tibial metaphysis and tibial diaphysis. Met significantly decreased body weight and bone mineral density (BMD) compared with Nrm. Aln and SrR significantly increased body weight and BMD compared with Met. SrR resulted in significantly higher BMD than Aln. Met markedly decreased BV/TV, Tb.Th, and Tb.N and increased Tb.Sp compared with Nrm. Aln and SrR showed significantly increased of BV/TV, Tb.Th, and Tb.N and improved bone architecture. Moreover, Met reduced %Ct.Ar, enlarged %Ma.Ar, and decreased bone formation indices in the periosteum as well as increased ES/BS in the endosteum compared with Nrm. Aln significantly decreased endosteal ES/BS compared with Met. SrR significantly increased %Ct.Ar and bone formation indices in the periosteum as well as the endosteum and decreased endosteal ES/BS compared with Met. Furthermore, SrR led to a significantly higher cancellous and endocortical MS/BS and endocortical bone formation compared with Aln. Our findings suggest SrR at a dose of 900 mg/kg has a greater effect than Aln at 1.0 mg/kg, according to BMD and histomorphometric analysis, in preventing GC-induced osteopenia. Therefore, SrR might be applicable as a bone therapeutic agent to treat secondary osteoporosis in the clinic. PMID:20390406

  14. Quantifying trabecular orientation in the pelvic cancellous bone of modern humans, chimpanzees, and the Kebara 2 Neanderthal.

    PubMed

    Martinón-Torres, María

    2003-01-01

    The adaptive nature of bone lies in its ability to respond to the environment by conforming and reshaping itself constantly to accommodate life-time stresses experienced throughout daily activities. In order to keep strains within the bone as uniform and isotropic as possible, the trabecular orientation is determined by forces acting on the bone through adaptive remodeling. Hence, the preserved structure of bones may contain direct information about the forces they may have undergone. Some authors (Correnti [1952], Atti Acc Naz Lincei 12:518-523, [1955] Riv Antrop 42:289-336; Macchiarelli et al. [1999] J Hum Evol 36:211-232, [2001] Cambridge, UK: Cambridge University Press) have described in detail the trabecular systems of the hip bone in different primate species and have identified a gait-related system above the acetabulum with substantial differences across species (Macchiarelli et al. [1999]; Rook et al. [1999] Proc Natl Acad Sci USA 96:8875-8879). The aim of this study was to quantify trabecular orientation above the acetabulum to test the hypothesis that hominoid biomechanical behavior is recorded in the cancellous bone. The pelvic bones of 23 archaeological adult modern humans (12 females, 11 males), 20 adult Pan troglodytes (10 females, 10 males), and one adult male Neanderthal were radiographed and digitized. Fast Fourier transforms (FFTs) of the regions of interest in the corpus of the ilium were performed, with the angular distribution of the trabeculae quantified. All species displayed a constant and periodic orthogonal arrangement in the trabeculae with differences in the pattern of dominance between the arcades oriented along the 0 degrees or the 90 degrees axes. The variation in the FFT spectrum between species is discussed in the light of distinctive biomechanical features. PMID:12953177

  15. Bone Mineral Status in Children and Adolescents with Klinefelter Syndrome

    PubMed Central

    Stagi, Stefano; Di Tommaso, Mariarosaria; Manoni, Cristina; Scalini, Perla; Chiarelli, Francesco; Verrotti, Alberto; Lapi, Elisabetta; Giglio, Sabrina; Dosa, Laura; de Martino, Maurizio

    2016-01-01

    Objective. Klinefelter syndrome (KS) has long-term consequences on bone health. However, studies regarding bone status and metabolism during childhood and adolescence are very rare. Patients. This cross-sectional study involved 40 (mean age: 13.7 ± 3.8 years) KS children and adolescents and 80 age-matched healthy subjects. For both patient and control groups, we evaluated serum levels of ionised and total calcium, phosphate, total testosterone, luteinising hormone, follicle stimulating hormone, parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline concentrations. We also calculated the z-scores of the phalangeal amplitude-dependent speed of sound (AD-SoS) and the bone transmission time (BTT). Results. KS children and adolescents showed significantly reduced AD-SoS (p < 0.005) and BTT (p < 0.0005) z-scores compared to the controls. However, KS patients presented significantly higher PTH (p < 0.0001) and significantly lower 25(OH)D (p < 0.0001), osteocalcin (p < 0.05), and bone alkaline phosphatase levels (p < 0.005). Interestingly, these metabolic bone disorders were already present in the prepubertal subjects. Conclusions. KS children and adolescents exhibited impaired bone mineral status and metabolism with higher PTH levels and a significant reduction of 25-OH-D and bone formation markers. Interestingly, this impairment was already evident in prepubertal KS patients. Follow-ups should be scheduled with KS patients to investigate and ameliorate bone mineral status and metabolism until the prepubertal ages. PMID:27413371

  16. Transforaminal lumbar interbody fusion rates in patients using a novel titanium implant and demineralized cancellous allograft bone sponge

    PubMed Central

    Girasole, Gerard; Muro, Gerard; Mintz, Abraham; Chertoff, Jason

    2013-01-01

    Background Transforaminal lumbar interbody fusion (TLIF) with grafting and implant options like iliac crest bone graft (ICBG), recombinant bone morphogenetic protein (rhBMP), and polyetheretherketone (PEEK) cages have been reported to achieve extremely high fusion rates. Unfortunately, these options have also been frequently cited in the literature as causing postoperative morbidity and complications at a high cost. Knowing this, we sought to investigate TLIF using an acid-etched, roughened titanium cage that upregulates osteogenesis to see if similar fusion rates to those cited for ICBG, rhBMP, and PEEK cages could be safely achieved with minimal morbidity and complications. Materials and methods A radiographic fusion study of 82 patients who underwent TLIF using an acid-etched, roughened titanium cage with demineralized cancellous bone graft was conducted. Fusion was assessed and graded by an independent radiologist using computed tomography scan with sagittal and coronal reconstructions. Results Fusion rates at 6 months were 41 of 44 (93.2%) and at 12 months were 37 of 38 (97.4%). There were no radiographic device-related complications. Conclusions TLIF with an acid-etched, roughened titanium cage filled with a decalcified bone graft achieved similar fusion rates to historical controls using ICBG, rhBMP, and PEEK. PMID:25580378

  17. Decomposition of two-component ultrasound pulses in cancellous bone using modified least squares prony method--phantom experiment and simulation.

    PubMed

    Wear, Keith A

    2010-02-01

    Porous media such as cancellous bone often support the simultaneous propagation of two compressional waves. When small bone samples are interrogated in through-transmission with broadband sources, these two waves often overlap in time. The modified least-squares Prony's (MLSP) method was tested for decomposing a 500 kHz-center-frequency signal containing two overlapping components: one passing through a polycarbonate plate (to produce the "fast" wave) and another passing through a cancellous-bone-mimicking phantom (to produce the "slow" wave). The MLSP method yielded estimates of attenuation slopes accurate to within 7% (polycarbonate plate) and 2% (cancellous bone phantom). The MLSP method yielded estimates of phase velocities accurate to within 1.5% (both media). The MLSP method was also tested on simulated data generated using attenuation slopes and phase velocities corresponding to bovine cancellous bone. Throughout broad ranges of signal-to-noise ratio (SNR), the MLSP method yielded estimates of attenuation slope that were accurate to within 1.0% and estimates of phase velocity that were accurate to within 4.3% (fast wave) and 1.3% (slow wave).

  18. The effect of supplementation of a glutamine precursor on the growth plate, articular cartilage and cancellous bone in fundectomy-induced osteopenic bone

    PubMed Central

    TOMASZEWSKA, Ewa; DOBROWOLSKI, Piotr; PROST, Łukasz; HUŁAS-STASIAK, Monika; MUSZYŃSKI, Siemowit; BLICHARSKI, Tomasz

    2015-01-01

    The aim of the study was to investigate the effect of 2-oxoglutaric acid (2-Ox) supplementation (a precursor of glutamine and hydroxyproline, the most abundant amino acid of collagen) on cartilage and bone in pigs after fundectomy. Pigs at the age of forty days were subjected to fundectomy and divided into two groups depending on 2-Ox supplementation (at the daily dosage of 0.4 g/kg of body weight). Other pigs were sham operated. Pigs were euthanized at the age of eight months. An analysis of the morphometry of trabeculae, growth plate and articular cartilage in fundectomy-induced osteopenic bone was performed. Moreover, the levels of expression of osteocalcin, osteopontin and osteoprotegerin in trabecular bone and osteocalcin in articular cartilage were evaluated. Articular cartilage was thinnest in fundectomized pigs and thickest in 2-Ox-supplemented animals after fundectomy. Moreover, 2-Ox supplementation after fundectomy enhanced the total thickness of the growth plate and trabeculae in fundectomized pigs. The most evident signal for osteocalcin and osteoprotegerin in trabecular bone was in sham-operated and 2-Ox-supplemented pigs; a low reaction was observed in the fundectomized group. Additionally, as a long-term postoperative consequence, a change was observed in the expression of osteocalcin in articular cartilage. It seems that 2-Ox is suitable for use in preventing the negative effects of fundectomy on cancellous bone and cartilage. PMID:26725871

  19. Insulin-like growth factor-1 suspended in hyaluronan improves cartilage and subchondral cancellous bone repair in osteoarthritis of temporomandibular joint.

    PubMed

    Liu, X-W; Hu, J; Man, C; Zhang, B; Ma, Y-Q; Zhu, S-S

    2011-02-01

    This study sought to evaluate the effects of intra-articular injection of insulin-like growth factor-1 (IGF-1) suspended in hyaluronan (HA) on the cartilage and subchondral cancellous bone repair in osteoarthritis (OA) of the temporomandibular joint (TMJ). Disc perforation was performed bilaterally in rabbit TMJs to induce OA. Four groups of animals (n=12) received OA induction only, and either intra-articular HA injection alone, intra-articular IGF-1 injection alone, or a combination of HA and IGF-1 injection. All therapy was begun 4 weeks after OA induction. The animals were killed 12 or 24 weeks after the first injection, for histology and micro-CT examinations. Two additional animals were used as normal controls. Typical cartilage and subchondral cancellous bone lesions were observed in the OA group. No protective effect on cartilage and subchondral cancellous bone was found in the HA or IGF-1 alone groups. Better histological repair and nearly normal micro-architectural properties of the subchondral cancellous bone were observed in the HA+IGF-1 group compared with the HA or IGF-1 alone groups. HA may be used as an effective carrier for intra-articular injection of IGF-1 and the combination of HA/IGF-1 shows promise as a new rational approach to therapy of TMJ OA. PMID:21055904

  20. Fabrication of cancellous biomimetic chitosan-based nanocomposite scaffolds applying a combinational method for bone tissue engineering.

    PubMed

    Jamalpoor, Zahra; Mirzadeh, Hamid; Joghataei, Mohammad Taghi; Zeini, Darya; Bagheri-Khoulenjani, Shadab; Nourani, Mohammad Reza

    2015-05-01

    The aim of this study was to mimic the specific structure of bone and fabricate a biomimetic nano-hydroxyapatite (HA)/chitosan (Cs)/gelatin scaffolds using combination of particle leaching and freeze drying methods eliminating mold effects. To achieve an optimum structure, scaffolds with different gelatin/Cs weight ratio were fabricated. Morphological characterization of scaffolds by scanning electron microscopy method showed highly interconnected porous structures similar to cancellous bone with mean pore size ranging from 140 to 190 μm. Nano-HA crystals were dispersed homogeneously in the polymer matrix according to the energy-dispersive X-ray spectroscopy and transmission electron microscopy images. Fourier transform infrared and X-ray diffraction results disclosed that chemical interactions were formed between nano-HA, Cs, gelatin and crystallinity of each material decreased with blending. It was found that increasing the gelatin content significantly improved water uptake, degradation rate as well as attachment, infiltration and proliferation of Saos2 cells to the scaffolds. The presented results confirm that the designed biomimetic nano-HA /Cs/gelatin scaffolds can be used as promising substitutes for bone tissue engineering.

  1. The Content of the 14 Metals in Cancellous and Cortical Bone of the Hip Joint Affected by Osteoarthritis

    PubMed Central

    Zioła-Frankowska, Anetta; Kubaszewski, Łukasz; Dąbrowski, Mikołaj; Kowalski, Artur; Rogala, Piotr; Strzyżewski, Wojciech; Łabędź, Wojciech; Uklejewski, Ryszard; Novotny, Karel; Kanicky, Viktor; Frankowski, Marcin

    2015-01-01

    The aim of the study was to determine the content of particular elements Ca, Mg, P, Na, K, Zn, Cu, Fe, Mo, Cr, Ni, Ba, Sr, and Pb in the proximal femur bone tissue (cancellous and cortical bone) of 96 patients undergoing total hip replacement for osteoarthritis using ICP-AES and FAAS analytical techniques. The interdependencies among these elements and their correlations depended on factors including age, gender, place of residence, tobacco consumption, alcohol consumption, exposure to environmental pollution, physical activity, and type of degenerative change which were examined by statistical and chemometric methods. The factors that exerted the greatest influence on the elements in the femoral head and neck were tobacco smoking (higher Cr and Ni content in smokers), alcohol consumption (higher concentrations of Ni, Cu in people who consume alcohol), and gender (higher Cu, Zn, and Ni concentrations in men). The factors influencing Pb accumulation in bone tissue were tobacco, alcohol, gender, and age. In primary and secondary osteoarthritis of the hip, the content and interactions of elements are different (mainly those of Fe and Pb). There were no significant differences in the concentrations of elements in the femoral head and neck that could be attributed to residence or physical activity. PMID:26357659

  2. The Content of the 14 Metals in Cancellous and Cortical Bone of the Hip Joint Affected by Osteoarthritis.

    PubMed

    Zioła-Frankowska, Anetta; Kubaszewski, Łukasz; Dąbrowski, Mikołaj; Kowalski, Artur; Rogala, Piotr; Strzyżewski, Wojciech; Łabędź, Wojciech; Uklejewski, Ryszard; Novotny, Karel; Kanicky, Viktor; Frankowski, Marcin

    2015-01-01

    The aim of the study was to determine the content of particular elements Ca, Mg, P, Na, K, Zn, Cu, Fe, Mo, Cr, Ni, Ba, Sr, and Pb in the proximal femur bone tissue (cancellous and cortical bone) of 96 patients undergoing total hip replacement for osteoarthritis using ICP-AES and FAAS analytical techniques. The interdependencies among these elements and their correlations depended on factors including age, gender, place of residence, tobacco consumption, alcohol consumption, exposure to environmental pollution, physical activity, and type of degenerative change which were examined by statistical and chemometric methods. The factors that exerted the greatest influence on the elements in the femoral head and neck were tobacco smoking (higher Cr and Ni content in smokers), alcohol consumption (higher concentrations of Ni, Cu in people who consume alcohol), and gender (higher Cu, Zn, and Ni concentrations in men). The factors influencing Pb accumulation in bone tissue were tobacco, alcohol, gender, and age. In primary and secondary osteoarthritis of the hip, the content and interactions of elements are different (mainly those of Fe and Pb). There were no significant differences in the concentrations of elements in the femoral head and neck that could be attributed to residence or physical activity. PMID:26357659

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

    PubMed

    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.

  4. Effects of Long-Term Daily Administration of Prostaglandin-E2 on Maintaining Elevated Proximal Tibial Metaphyseal Cancellous Bone Mass in Male Rats

    NASA Technical Reports Server (NTRS)

    Ke, Hua Zhu; Jee, Webster S. S.; Mori, Satoshi; Li, Xiao Jian; Kimmel, Donald B.

    1992-01-01

    The effects of long-term prostaglandin E(sub 2) (PGE(sub 2)) on cancellous bone in proximal tibial metaphysis were studied in 7 month old male Sprague-Dawley rats given daily subcutaneous injections of 0, 1, 3, and 6 mg PGE(sub 2)/kg/day and sacrificed after 60, 120, and 180 days. Histomorphometric analyses were performed on double fluorescent-labeled undecalcified bone specimens. After 60 days of treatment, PGE(sub 2) produced diffusely labeled trabecular bone area, increased trabecular bone area, eroded and labeled trabecular perimeter, mineral apposition rate, and bone formation rate at all dose levels when compared with age-matched controls. In rats given PGE(sub 2) for longer time periods (120 and 180 days), trabecular bone area, diffusely labeled trabecular bone area, labeled perimeter, mineral apposition, and bone formation rates were sustained at the elevated levels achieved earlier at 60-day treatment. The eroded perimeter continued to increase until 120 days, then plateau. The observation that continuous systemic PGE(sub 2) administration to adult male rats elevated metaphyseal cancellous bone mass to 3.5-fold of the control level within 60 days and maintained it for another 120 days indicates that the powerful skeletal anabolic effects of PGE2 can be sustained with continuous administration .

  5. Hip bone strength indices in overweight and control adolescent boys.

    PubMed

    El Hage, Zaher; Theunynck, Denis; Jacob, Christophe; Moussa, Elie; Baddoura, Rafic; Kamlé, Pierre; El Hage, Rawad

    2011-11-01

    The influence of being overweight on bone strength in adolescents remains controversial. The aim of this study was to compare hip bone strength indices in overweight and control adolescent boys using hip structure analysis (HSA). This study included 25 overweight adolescent boys [body mass index (BMI) >25 kg/m(2)] and 31 maturation-matched controls (BMI <25 kg/m(2)). Body composition and bone mineral density were assessed by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone strength, DXA scans were analyzed at femoral neck, intertrochanteric, and femoral shaft by the HSA program. Cross-sectional area (CSA), an index of axial compression strength, section modulus (Z), an index of bending strength, cross-sectional moment of inertia (CSMI), cortical thickness (CT), and buckling ratio (BR) were measured from bone mass profiles. Body weight, lean mass, fat mass, and BMI were higher in overweight boys compared to controls (P < 0.001). CSA, CSMI, and Z of the three sites (femoral neck, intertrochanteric, and femoral shaft) were higher in overweight boys compared to controls (P < 0.01). BR was not significantly different between the two groups at the three sites. After adjustment for either body weight, BMI, or fat mass, using a one-way analysis of covariance, there were no differences between the two groups regarding the HSA variables (CSA, Z, CSMI, CT, and BR). After adjusting for lean mass, overweight boys displayed higher values of femoral shaft CSA, CSMI, and Z in comparison to controls (P < 0.05). In conclusion, this study suggests that overweight adolescent boys have greater indices of bone axial and bending strength in comparison to controls at the femoral neck, the intertrochanteric, and the femoral shaft.

  6. Quantitation and localisation of aluminum in human cancellous bone in renal osteodystrophy

    SciTech Connect

    Boyce, B.F.; Eider, H.Y.; Fell, S.G.; Nicholson, W.A.; Smith, G.D.; Dempster, D.W.; Gray, C.C.; Boyle, I.T.

    1981-01-01

    There is increasing evidence that aluminium toxicity may be responsible for a type of vitamin D-resistant osteomalacia and an unusually severe form of dementia (''dialysis dementia'') occurring in some patients with chronic renal failure on regular haemodialysis. High concentrations of Al have been found in blood, bone and brain tissue from these patients. The A1 comes either from the water used during dialysis (added in some public water supplies during purification to precipitate contaminants) or from aluminium salts taken orally to bind phosphates and so restrict their dietary adsorption. Recent X-ray microanalytical studies have demonstrated Al in lysosomes of cerebral cells and at the calcification front in bone of patients dying of dialysis dementia but its concentration at this site in bone has not been measured using this technique. We have examined transiliac bone biopsies from 3 patients with dialysis dementia and 6 non-demented patients on regular haemodialysis, Atomic absorption spectrometry (AAS) reveals high Al content in bone from the 3 demented and 2 of the non-demented patients. All had vitamin D-resistant osteomalacia. Using X-ray microanalysis Al was located in the bone of these five patients only. The Al had a highly focal distribution and was measured at up to 40 times higher concentration than by AAS but only in mineralisation nuclei of the calcification front or less than 2 micrometer into the mineralized bone. The study was done retrospectively on biopsies fixed in 10% buffered formalin, which almost certainly eluted some of the Al. In life, Al levels may have been higher than those we have detected.

  7. Inverse problems in cancellous bone: Estimation of the ultrasonic properties of fast and slow waves using Bayesian probability theory

    PubMed Central

    Anderson, Christian C.; Bauer, Adam Q.; Holland, Mark R.; Pakula, Michal; Laugier, Pascal; Bretthorst, G. Larry; Miller, James G.

    2010-01-01

    Quantitative ultrasonic characterization of cancellous bone can be complicated by artifacts introduced by analyzing acquired data consisting of two propagating waves (a fast wave and a slow wave) as if only one wave were present. Recovering the ultrasonic properties of overlapping fast and slow waves could therefore lead to enhancement of bone quality assessment. The current study uses Bayesian probability theory to estimate phase velocity and normalized broadband ultrasonic attenuation (nBUA) parameters in a model of fast and slow wave propagation. Calculations are carried out using Markov chain Monte Carlo with simulated annealing to approximate the marginal posterior probability densities for parameters in the model. The technique is applied to simulated data, to data acquired on two phantoms capable of generating two waves in acquired signals, and to data acquired on a human femur condyle specimen. The models are in good agreement with both the simulated and experimental data, and the values of the estimated ultrasonic parameters fall within expected ranges. PMID:21110589

  8. Bone acquisition during adolescence in athletes.

    PubMed

    Markou, Kostas B; Theodoropoulou, Anastasia; Tsekouras, Athanasios; Vagenakis, Apostolos G; Georgopoulos, Neoklis A

    2010-09-01

    Bone mass (BM) and skeletal size are similar in prepubertal girls and boys and double between the onset of puberty and early adult life. Sex steroids are responsible for the maturation in human skeleton, as well as for the sexual dimorphism, observed after the onset of puberty. Physical activity in childhood is critical for maximizing bone growth and thus for preventing osteoporosis during older age. Therefore, it constitutes the most effective prevention strategy available. In athletes, high-impact loading activities have been shown to improve BM, whereas in sports requiring a lean somatotype (therefore leading to a negative energy balance), the delay in skeletal maturation and pubertal development predisposes athletes to osteopenia and osteoporosis. Although the early onset of training, the continuous intensive exercise and its long duration attenuate bone acquisition, the excess mechanical load to which these athletes are exposed from a young age exerts beneficial effects on bone formation that lead to a positive net-effect on BM.

  9. Ultrasonic scanner for in vivo measurement of cancellous bone properties from backscattered data.

    PubMed

    Litniewski, Jerzy; Cieslik, Lucyna; Lewandowski, Marcin; Tymkiewicz, Ryszard; Zienkiewicz, Boguslaw; Nowicki, Andrzej

    2012-07-01

    A dedicated ultrasonic scanner for acquiring RF echoes backscattered from the trabecular bone was developed. The design of device is based on the goal of minimizing of custom electronics and computations executed solely on the main computer processor and the graphics card. The electronic encoder-digitizer module executing all of the transmission and reception functions is based on a single low-cost field programmable gate array (FPGA). The scanner is equipped with a mechanical sector-scan probe with a concave transducer with 50 mm focal length, center frequency of 1.5 MHz and 60% bandwidth at -6 dB. The example of femoral neck bone examination shows that the scanner can provide ultrasonic data from deeply located bones with the ultrasound penetrating the trabecular bone up to a depth of 20 mm. It is also shown that the RF echo data acquired with the scanner allow for the estimation of attenuation coefficient and frequency dependence of backscattering coefficient of trabecular bone. The values of the calculated parameters are in the range of corresponding in vitro data from the literature but their variation is relatively high.

  10. Cancellous bone healing around strontium-doped hydroxyapatite in osteoporotic rats previously treated with zoledronic acid.

    PubMed

    Li, Yunfeng; Shui, Xueping; Zhang, Li; Hu, Jing

    2016-04-01

    Bisphosphonates (BPs) are potent anti-osteoporotic agents. Strontium-doped hydroxyapatite (HA) (SrHA) has been reported to increase bone density and improve trabecular microarchitecture in osteoporotic animals. But information about the effect of SrHA on the surrounding bone tissue in osteoporotic animals previously on BPs treatment is limited. We hypothesize that SrHA will induce increased bone density in the vicinity of the material when compared to HA, even in osteoporotic animals previously treated with BPs. HA and 10%SrHA (HA with 10 mol % calcium substituted by strontium) implants were prepared and characterized by scanning electronic microscopy (SEM), X-ray photoemission spectroscopy (XPS), and X-ray diffraction (XRD). Osteoporotic animal model was established by bilateral ovariectomy. Twelve weeks later, all OVX rats accepted subcutaneous injection of zoledronic acid (ZOL) at the dose of 1.5 μg/kg weekly for another twelve weeks. Subsequently, rod-shaped HA and SrHA implants were inserted in the distal femur of the OVX animals previously treated with ZOL. Eight weeks after implantation, specimens were harvested for histological and micro-computed tomography (micro-CT) analysis. Compared to HA, 10%SrHA raised the percent bone volume by 32.7%, the mean trabecular thickness by 36.5%, the mean trabecular number by 34.3%, the mean connectivity density by 38.4%, while the mean trabecular separation showed no significant difference. 10%SrHA also increased the bone area density by 36.3% in histological analysis. Results from this study indicated that 10%SrHA increased bone density and improved trabecular microarchitecture around implants in osteoporotic animals previously treated with ZOL when compared to HA. PMID:25891947

  11. Body Mass, Training, Menses, and Bone in Adolescent Runners: A 3-y Follow-Up

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: Endurance runners with low bone mass during adolescence may be at risk of developing a low peak bone mineral density (BMD) as a young adult. However, it is possible that they mature late and undergo delayed bone mass accumulation. PURPOSE: We evaluated 40 adolescent runners (age 15.9 ± 0....

  12. Effects of Prostaglandin E2 and Risedronate Administration on Cancellous Bone in Older Female Rats

    NASA Technical Reports Server (NTRS)

    Lin, B. Y.; Jee, W. S. S.; Ma, Y. F.; Ke, H. Z.; Kimmel, D. B.; Li, X. J.

    1994-01-01

    The effects of Prostaglandin E2 (PGE2) and Risedronate (Ris) both separately and in combination (PGE2 + Ris) were studied on the intact aged female rat skeleton to determine whether the combination of PGE2 with an antiresorptive agent is more effective anabolically than PGE2 alone. Nine month-old Sprague-Dawley rats were injected subcutaneously either with vehicle, 6 mg PGE2/kg per day, 1 or 5 microgram Ris/kg twice a week, or 6 mg PGE2/kg per day plus 1 or 5 microgram Ris/kg twice a week (PGE2 + 1 Ris or PGE2 + 5 Ris) for 60 days. After the treatment, we determined the longitudinal bone growth rate, the qualitative appearance of the primary spongiosa (PS), and the static and dynamic bone histomorphometry of the secondary spongiosa (SS) of the proximal tibial metaphysis (PTM) by examining undecalcified longitudinal sections after double fluorescent labeling. The relative effects of these treatments on longitudinal bone growth were ranked as follows: PGE2 + 5 Ris greater than PGE2 + 1 Ris = basal greater than PGE2 greater than 1 microgram Ris = 5 microgram Ris = aging. The density of the PS was ranked as follows: PGE2 + 5 Ris greater than PGE2 + 1 Ris = PGE2 = 5 microgram Ris = 1 microgram Ris greater than basal = aging. The increase in density of the PS was the result of stimulated longitudinal growth and the action of bisphosphonate. Bone mass in the SS was ranked as follows: PGE2 + 5 Ris = PGE2 + 1 Ris = PGE2 greater than 5 microgram Ris = 1 microgram Ris = aging = basal. However, PGE2 alone and its cotreatment with Ris accumulated bone by different tissue mechanisms. PGE2 alone created new bone by increasing activation frequency 8.3-fold and the formation to resorption ratio 1.3-fold from the controls. The combination of PGE2 and Ris depressed activation frequency (-54% to -74%), and bone formation rate (tissue-based -31%, and bone-based -42%) and eroded surface (-79% to -81%), so as to increase the formation to resorption ratio (three- to four-fold) over PGE2

  13. Bone Mineral Density in Healthy Female Adolescents According to Age, Bone Age and Pubertal Breast Stage

    PubMed Central

    Moretto, M.R; Silva, C.C; Kurokawa, C.S; Fortes, C.M; Capela, R.C; Teixeira, A.S; Dalmas, J.C; Goldberg, T.B

    2011-01-01

    Objectives: This study was designed to evaluate bone mineral density (BMD) in healthy female Brazilian adolescents in five groups looking at chronological age, bone age, and pubertal breast stage, and determining BMD behavior for each classification. Methods: Seventy-two healthy female adolescents aged between 10 to 20 incomplete years were divided into five groups and evaluated for calcium intake, weight, height, body mass index (BMI), pubertal breast stage, bone age, and BMD. Bone mass was measured by bone densitometry (DXA) in lumbar spine and proximal femur regions, and the total body. BMI was estimated by Quetelet index. Breast development was assessed by Tanner’s criteria and skeletal maturity by bone age. BMD comparison according to chronologic and bone age, and breast development were analyzed by Anova, with Scheffe’s test used to find significant differences between groups at P≤0.05. Results: BMD (g·cm-2) increased in all studied regions as age advanced, indicating differences from the ages of 13 to 14 years. This group differed to the 10 and 11 to 12 years old groups for lumbar spine BMD (0.865±0.127 vs 0.672±0.082 and 0.689±0.083, respectively) and in girls at pubertal development stage B3, lumbar spine BMD differed from B5 (0.709±0.073 vs 0.936±0.130) and whole body BMD differed from B4 and B5 (0.867±0.056 vs 0.977±0.086 and 1.040±0.080, respectively). Conclusion: Bone mineralization increased in the B3 breast maturity group, and the critical years for bone mass acquisition were between 13 and 14 years of age for all sites evaluated by densitometry. PMID:21966336

  14. Fast and slow wave detection in bovine cancellous bone in vitro using bandlimited deconvolution and Prony's method.

    PubMed

    Wear, Keith; Nagatani, Yoshiki; Mizuno, Katsunori; Matsukawa, Mami

    2014-10-01

    Fast and slow waves were detected in a bovine cancellous bone sample for thicknesses ranging from 7 to 12 mm using bandlimited deconvolution and the modified least-squares Prony's method with curve fitting (MLSP + CF). Bandlimited deconvolution consistently isolated two waves with linear-with-frequency attenuation coefficients as evidenced by high correlation coefficients between attenuation coefficient and frequency: 0.997 ± 0.002 (fast wave) and 0.986 ± 0.013 (slow wave) (mean ± standard deviation). Average root-mean-squared (RMS) differences between the two algorithms for phase velocities were 5 m/s (fast wave, 350 kHz) and 13 m/s (slow wave, 750 kHz). Average RMS differences for signal loss were 1.6 dB (fast wave, 350 kHz) and 0.4 dB (slow wave, 750 kHz). Phase velocities for thickness = 10 mm were 1726 m/s (fast wave, 350 kHz) and 1455 m/s (slow wave, 750 kHz). Results show support for the model of two waves with linear-with frequency attenuation, successful isolation of fast and slow waves, good agreement between bandlimited deconvolution and MLSP + CF as well as with a Bayesian algorithm, and potential variations of fast and/or slow wave properties with bone sample thickness.

  15. Characteristics of osteoma of the temporal bone in young adolescents.

    PubMed

    Viswanatha, Borlingegowda

    2011-02-01

    The author conducted a retrospective review of the clinical presentation, management, and complications of temporal bone osteoma in young adolescents. The study population was made up of 9 patients-5 girls and 4 boys, aged 12 to 15 years at presentation (mean: 13.7)-who had been seen for radiologically and histopathologically proven temporal bone osteoma at the author's institution over a 9-year period. Of this group, 5 patients had extracanalicular osteoma (3 in the mastoid portion of the temporal bone, 1 in the squamous portion, and 1 in the mastoid antrum) and 4 patients had osteoma of the external auditory canal. Six of the 9 patients underwent surgical treatment; of the remainder, 1 refused surgery and 2 were managed conservatively with ongoing observation. All patients were followed for a minimum of 1 year, and no recurrences and no complications were observed during that time.

  16. Delayed Union of a Sacral Fracture: Percutaneous Navigated Autologous Cancellous Bone Grafting and Screw Fixation

    SciTech Connect

    Huegli, R. W. Messmer, P.; Jacob, A. L.; Regazzoni, P.; Styger, S.; Gross, T.

    2003-09-15

    Delayed or non-union of a sacral fracture is a serious clinical condition that may include chronic pain, sitting discomfort, gait disturbances, neurological problems, and inability to work. It is also a difficult reconstruction problem. Late correction of the deformity is technically more demanding than the primary treatment of acute pelvic injuries. Open reduction, internal fixation (ORIF), excision of scar tissue, and bone grafting often in a multi-step approach are considered to be the treatment of choice in delayed unions of the pelvic ring. This procedure implies the risk of neurological and vascular injuries, infection, repeated failure of union, incomplete correction of the deformity, and incomplete pain relief as the most important complications. We report a new approach for minimally invasive treatment of a delayed union of the sacrum without vertical displacement. A patient who suffered a Malgaigne fracture (Tile C1.3) was initially treated with closed reduction and percutaneous screw fixation (CRPF) of the posterior pelvic ring under CT navigation and plating of the anterior pelvic ring. Three months after surgery he presented with increasing hip pain caused by a delayed union of the sacral fracture. The lesion was successfully treated percutaneously in a single step procedure using CT navigation for drilling of the delayed union, autologous bone grafting, and screw fixation.

  17. Tracking of Bone Mass and Density during Childhood and Adolescence

    PubMed Central

    Kalkwarf, Heidi J.; Gilsanz, Vicente; Lappe, Joan M.; Oberfield, Sharon; Shepherd, John A.; Hangartner, Thomas N.; Huang, Xangke; Frederick, Margaret M.; Winer, Karen K.; Zemel, Babette S.

    2010-01-01

    Context: Whether a child with low bone mineral density (BMD) at one point in time will continue to have low BMD, despite continued growth and maturation, is important clinically. The stability of a characteristic during growth is referred to as “tracking.” Objective: We examined the degree of tracking in bone mineral content (BMC) and BMD during childhood and adolescence and investigated whether tracking varied according to age, sexual maturation, and changes in growth status. Design: We conducted a longitudinal study with measurements at baseline and annually for 3 yr. Setting: The Bone Mineral Density in Childhood Study was conducted at five clinical centers in the United States. Study Participants: A total of 1554 girls and boys, ages 6–16 yr at baseline, participated in the study. Main Outcome Measures: Whole body, spine, hip, and forearm BMC and BMD were measured by dual-energy x-ray absorptiometry, and age-, sex-, and race-specific Z-scores were calculated. Deviation from tracking was calculated as the Z-score at yr 3 minus baseline. Results: Correlations between Z-scores at baseline and yr 3 ranged from 0.76–0.88. Among children with a Z-score below −1.5 at baseline, 72–87% still had a Z-score below −1 after 3 yr. Age, sexual maturation, and deviations in growth status (P < 0.01) were associated with deviation from tracking; however, tracking was strongly evident even after adjusting for the effects of age, maturation, and growth. Conclusions: Bone density showed a high degree of tracking over 3 yr in children and adolescents. Healthy children with low bone density will likely continue to have low bone density unless effective interventions are instituted. PMID:20194709

  18. Numerical Analysis of Ultrasound Backscattered Waves in Cancellous Bone Using a Finite-Difference Time-Domain Method: Isolation of the Backscattered Waves From Various Ranges of Bone Depths.

    PubMed

    Hosokawa, Atsushi

    2015-06-01

    Using a finite-difference time-domain method, ultrasound backscattered waves inside cancellous bone were numerically analyzed to investigate the backscatter mechanism. Two bone models with different thicknesses were modeled with artificial absorbing layers positioned at the back surfaces of the model, and an ultrasound pulse wave was transmitted toward the front surface. By calculating the difference between the simulated waveforms obtained using the two bone models, the backscattered waves from a limited range of depths in cancellous bone could be isolated. The results showed that the fast and slow longitudinal waves, which have previously been observed only in the ultrasound waveform transmitted through the bone, could be distinguished in the backscattered waveform from a deeper bone depth when transmitting the ultrasound wave parallel to the main orientation of the trabecular network. The amplitudes of the fast and slow backscattered waves were more closely correlated with the bone porosity [R2 = 0.84 and 0.66 (p < 0.001), respectively] than the amplitude of the whole (nonisolated) backscattered waves [R2 = 0.48 (p < 0.001)]. In conclusion, the nonisolated backscattered waves could be regarded as the superposition of the fast and slow waves reflected from various bone depths, returning at different times.

  19. Assessing cement injection behaviour in cancellous bone: an in vitro study using flow models.

    PubMed

    Bou-Francis, Antony; López, Alejandro; Persson, Cecilia; Hall, Richard M; Kapur, Nikil

    2014-10-01

    Understanding the cement injection behaviour during vertebroplasty and accurately predicting the cement placement within the vertebral body is extremely challenging. As there is no standardized methodology, we propose a novel method using reproducible and pathologically representative flow models to study the influence of cement properties on injection behaviour. The models, confined between an upper glass window and a lower aluminium plate, were filled with bone marrow substitute and then injected (4, 6 and 8 min after cement mixing) with commercially available bone cements (SimplexP, Opacity+, OsteopalV and Parallax) at a constant flow rate (3 mL/min). A load cell was used to measure the force applied on the syringe plunger and calculate the peak pressure. A camera was used to monitor the cement flow during injection and calculate the following parameters when the cement had reached the boundary of the models: the time to reach the boundary, the filled area and the roundness. The peak pressure was comparable to that reported during clinical vertebroplasty and showed a similar increase with injection time. The study highlighted the influence of cement formulations and model structure on the injection behaviour and showed that cements with similar composition/particle size had similar flow behaviour, while the introduction of defects reduced the time to reach the boundary, the filled area and the roundness. The proposed method provides a novel tool for quick, robust differentiation between various cement formulations through the visualization and quantitative analysis of the cement spreading at various time intervals. PMID:24913614

  20. Sclerostin levels and bone turnover markers in adolescents with anorexia nervosa and healthy adolescent girls.

    PubMed

    Faje, Alexander T; Fazeli, Pouneh K; Katzman, Debra K; Miller, Karen K; Breggia, Anne; Rosen, Clifford J; Mendes, Nara; Klibanski, Anne; Misra, Madhusmita

    2012-09-01

    Sclerostin, product of the SOST gene, is an important determinant of bone formation and resorption. Adolescents with anorexia nervosa (AN) have low bone density and decreased levels of bone turnover markers. However, sclerostin has not been examined in AN as a potential mediator of impaired bone metabolism. Our study objectives were to (i) assess associations of sclerostin with surrogate bone turnover markers in girls with AN and controls and (ii) examine effects of transdermal estradiol on sclerostin in AN. 69 girls (44 with AN and 25 normal-weight controls) 13-18 years old were studied at baseline. 22 AN girls were randomized to transdermal estradiol (plus cyclic medroxyprogesterone) or placebo in a double-blind study for 12 months. Sclerostin correlated positively with P1NP and CTX in controls (r=0.67 and 0.53, p=0.0002 and 0.005, respectively) but not in AN despite comparable levels at baseline. Changes in sclerostin over twelve months did not differ in girls randomized to estradiol or placebo. The relationship between sclerostin and bone turnover markers is disrupted in adolescent girls with AN. Despite an increase in BMD with estradiol administration in AN, estrogen does not impact sclerostin levels in this group.

  1. Psychiatric Sequelae in Adolescent Bone Marrow Transplantation Survivors

    PubMed Central

    STUBER, MARGARET L.; NADER, KATHLEEN O.

    1995-01-01

    Survivors of life-threatening pediatric illness and their families present a number of psychotherapeutic challenges. The authors present pilot data evaluating the long-term psychiatric impact of pediatric bone marrow transplantation on 10 adolescent transplantation survivors compared with a matched control group. On a quantitative assessment of posttraumatic stress symptoms, the survivors reported a consistent but low level of symptoms. Their narratives about the experience suggest the need for ongoing mental health assessment in addition to specific interventions with families early in the treatment. PMID:22700211

  2. Histomorphometric Assessment of Cancellous and Cortical Bone Material Distribution in the Proximal Humerus of Normal and Osteoporotic Individuals: Significantly Reduced Bone Stock in the Metaphyseal and Subcapital Regions of Osteoporotic Individuals.

    PubMed

    Sprecher, Christoph M; Schmidutz, Florian; Helfen, Tobias; Richards, R Geoff; Blauth, Michael; Milz, Stefan

    2015-12-01

    Osteoporosis is a systemic disorder predominantly affecting postmenopausal women but also men at an advanced age. Both genders may suffer from low-energy fractures of, for example, the proximal humerus when reduction of the bone stock or/and quality has occurred.The aim of the current study was to compare the amount of bone in typical fracture zones of the proximal humerus in osteoporotic and non-osteoporotic individuals.The amount of bone in the proximal humerus was determined histomorphometrically in frontal plane sections. The donor bones were allocated to normal and osteoporotic groups using the T-score from distal radius DXA measurements of the same extremities. The T-score evaluation was done according to WHO criteria. Regional thickness of the subchondral plate and the metaphyseal cortical bone were measured using interactive image analysis.At all measured locations the amount of cancellous bone was significantly lower in individuals from the osteoporotic group compared to the non-osteoporotic one. The osteoporotic group showed more significant differences between regions of the same bone than the non-osteoporotic group. In both groups the subchondral cancellous bone and the subchondral plate were least affected by bone loss. In contrast, the medial metaphyseal region in the osteoporotic group exhibited higher bone loss in comparison to the lateral side.This observation may explain prevailing fracture patterns, which frequently involve compression fractures and certainly has an influence on the stability of implants placed in this medial region. It should be considered when planning the anchoring of osteosynthesis materials in osteoporotic patients with fractures of the proximal humerus.

  3. Effects of High-LET Radiation Exposure and Hindlimb Unloading on Skeletal Muscle Resistance Artery Vasomotor Properties and Cancellous Bone Microarchitecture in Mice.

    PubMed

    Ghosh, Payal; Behnke, Brad J; Stabley, John N; Kilar, Cody R; Park, Yoonjung; Narayanan, Anand; Alwood, Joshua S; Shirazi-Fard, Yasaman; Schreurs, Ann-Sofie; Globus, Ruth K; Delp, Michael D

    2016-03-01

    Weightlessness during spaceflight leads to functional changes in resistance arteries and loss of cancellous bone, which may be potentiated by radiation exposure. The purpose of this study was to assess the effects of hindlimb unloading (HU) and total-body irradiation (TBI) on the vasomotor responses of skeletal muscle arteries. Male C57BL/6 mice were assigned to control, HU (13-16 days), TBI (1 Gy (56)Fe, 600 MeV, 10 cGy/min) and HU-TBI groups. Gastrocnemius muscle feed arteries were isolated for in vitro study. Endothelium-dependent (acetylcholine) and -independent (Dea-NONOate) vasodilator and vasoconstrictor (KCl, phenylephrine and myogenic) responses were evaluated. Arterial endothelial nitric oxide synthase (eNOS), superoxide dismutase-1 (SOD-1) and xanthine oxidase (XO) protein content and tibial cancellous bone microarchitecture were quantified. Endothelium-dependent and -independent vasodilator responses were impaired in all groups relative to control, and acetylcholine-induced vasodilation was lower in the HU-TBI group relative to that in the HU and TBI groups. Reductions in endothelium-dependent vasodilation correlated with a lower cancellous bone volume fraction. Nitric oxide synthase inhibition abolished all group differences in endothelium-dependent vasodilation. HU and HU-TBI resulted in decreases in eNOS protein levels, while TBI and HU-TBI produced lower SOD-1 and higher XO protein content. Vasoconstrictor responses were not altered. Reductions in NO bioavailability (eNOS), lower anti-oxidant capacity (SOD-1) and higher pro-oxidant capacity (XO) may contribute to the deficits in NOS signaling in skeletal muscle resistance arteries. These findings suggest that the combination of insults experienced in spaceflight leads to impairment of vasodilator function in resistance arteries that is mediated through deficits in NOS signaling. PMID:26930379

  4. Bone Health in Adolescent Athletes with a Focus on Female Athlete Triad

    PubMed Central

    Ackerman, Kathryn E.; Misra, Madhusmita

    2013-01-01

    Peak bone mass (PBM) is a negative predictor of osteoporosis and life-long fracture risk. Because osteoporosis is such a prevalent disease with life-threatening consequences later in life, it is important to try to maximize PBM. Adolescence is a critical time for bone acquisition. This review discusses some of the differences in male and female skeletal development and modifiable factors that enhance bone accrual in this age group, particularly in athletes. Hormonal influences, physical activity effects, and nutritional contributions are presented, with a focus on the adolescent athlete. Emphasis is placed on the importance of appropriate energy availability in this age group. The Female Athlete Triad (the inter-relationship of decreased energy availability, menstrual irregularity, and low bone density) is an important issue for adolescent, athletic women, and is therefore reviewed, including prevention and treatment strategies. Recommendations for maximizing bone density in both male and female adolescents are discussed. PMID:21378496

  5. Preparation of a biphasic porous bioceramic by heating bovine cancellous bone with Na4P2O7.10H2O addition.

    PubMed

    Lin, F H; Liao, C J; Chen, K S; Sun, J S

    1999-03-01

    Sintered bovine cancellous bone exhibited excellent biocompatiblity, high porosity and have an interconnecting porous structure allowing for bone ingrowth. However, the main mineral constitution of sintered bovine bone-hydroxyapatite (Ca10(PO4)6(OH)2, HAP) seems to be too stable in vivo. For improving its bioactivity, the calcined bovine bone removing the organic substance by burning process-with different quantities of sodium pyrophosphate (Na4P2O7.10H2O, NP) addition was heated to a high temperature to transform its crystalline phase constitution from HAP into TCP/HAP biphasic or other multiphasic structures. Results revealed that the calcined bovine bone without NP addition, exhibited a pure form of HAP characterized pattern during heating. Its thermal behavior was similar to stoichiometric HAP, it gradually lost its OH- ions and transformed into oxyhydroxyapatite at high temperature. After being doped into calcined bovine bone, NP would react with HAP to form betaBTCP and NaCaPO4 around 600 degrees C. At 900 degrees C, doped NP would completely react with HAP and the NaCaPO4 would further react with HAP to form more betaBTCP in the system. With NP increasing in the calcined bovine bone, HAP would gradually convert into different crystalline phase compositions of TCP/HAP, TCP/HAP/NaCaPO4 or TCP/NaCaPO4 at high temperature. By heating calcined bovine cancellouse bone with different quantities of NP we could obtain different crystalline phase compositions of natural porous bioceramic in this study.

  6. EFFECTS OF CHEMICAL PROCESSING AND OXIDE ETHYLENE STERILIZATION ON CORTICAL AND CANCELLOUS RAT BONE: A LIGHT AND ELECTRON SCANNING MICROSCOPY STUDY

    PubMed Central

    Castiglia, Marcello Teixeira; da Silva, Juliano Voltarelli F.; Frezarim Thomazini, José Armendir; Volpon, José Batista

    2015-01-01

    To evaluate, under microscopic examination, the structural changes displayed by the trabecular and cortical bones after being processed chemically and sterilized by ethylene oxide. Methods: Samples of cancellous and cortical bones obtained from young female albinus rats (Wistar) were assigned to four groups according to the type of treatment: Group I- drying; Group II- drying and ethylene oxide sterilization; III- chemical treatment; IV- chemical treatment and ethylene oxide sterilization. Half of this material was analyzed under ordinary light microscope and the other half using scanning electron microscopy. Results: In all the samples, regardless the group, there was good preservation of the general morphology. For samples submitted to the chemical processing there was better preservation of the cellular content, whereas there was amalgamation of the fibres when ethylene oxide was used. Conclusion: Treatment with ethylene oxide caused amalgamation of the fibers, possibly because of heating and the chemical treatment contributed to a better cellular preservation of the osseous structure. PMID:26998450

  7. Hypothalamic Suppression during Adolescence Varies by Bone Envelope

    PubMed Central

    SAINE, MCKAYLA ELLE; BARBE, MARY F.; AGAH, MOBIN RASTGAR; YINGLING, VANESSA R.

    2013-01-01

    Purpose The purposes of this study were to suppress estradiol levels in adolescent (postpubertal rats) using gonadotropin-releasing hormone antagonist (GnRH-a) injections and to determine the changes in bone structure and mechanical strength. Methods In an Institutional Animal Care and Use Committee–approved study, female rats at 23 d of age were assigned to a baseline group (BL65; n = 10) sacrificed on day 65, a control group (Control; n = 15) sacrificed on day 90, or an experimental group (AMEN; n = 9) sacrificed on day 90 that received daily injections of GnRH-a for a 25-d period from 65 to 90 d of age (2.5 mg·kg−1 per dose). Results Body weights were similar on day 65; however, the AMEN group was significantly heavier than the Control group (17%, P = 0.001) on day 90. In the AMEN rats relative to the Control group, plasma estradiol levels were reduced by 36% (P = 0.0001) and plasma insulin-like growth factor 1 levels were 24% higher (P = 0.003). In the femur, there was no change in periosteal bone apposition or total cross-sectional area. The marrow area increased by 13.7% (P = 0.05) resulting in a 7.8% decrease in relative cortical area (P = 0.012), and endocortical bone formation rate increased by 39.4% (P = 0.04). Trabecular volume and number decreased by 51.5% (P = 0.0003) and 49.5% (P = 0.0003), respectively. The absolute peak moments of the tibiae and femurs were unchanged in the AMEN group relative to the Control group, but these were reduced by 8.8% (P = 0.03) and 7.5% (P = 0.09), respectively, when normalized by body weight. Conclusions Suppression of estradiol by 25 d of GnRH-a administration to 65-d-old (postpubertal) rats reduced trabecular volume and number by about 50%, increased endocortical bone turnover, and reduced relative cortical thickness without changing tibial and femoral total area. These changes in bone structure were associated with no change in absolute mechanical strength possibly because of increases in body weight or in

  8. In vitro effectiveness of antimicrobial photodynamic therapy (APDT) using a 660 nm laser and malachite green dye in Staphylococcus aureus biofilms arranged on compact and cancellous bone specimens.

    PubMed

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

    2014-11-01

    The aim of this study was to evaluate the in vitro effectiveness of antimicrobial photodynamic therapy (APDT) using a 660 nm visible laser combined with malachite green (MG) dye in the inactivation of Staphylococcus aureus (ATCC 25923) biofilms formed within compact and cancellous bone specimens. Specimens of 80 compact bones and 80 cancellous bones were contaminated with a standard suspension of S. aureus and incubated for 14 days at 37 °C to allow for the formation of biofilms. The specimens were divided into the following groups (n = 10) according to the treatment conditions: PS-L - (control - no treatment), PS+L - (only MG for 5 min), PS-L + 90 (only laser irradiation for 90 s), PS-L + 180 (only laser irradiation for 180 s), PS-L + 300 (only laser irradiation for 300 s), APDT90 (APDT for 90 s), APDT180 (APDT for 180 s), and APDT300 (APDT for 300 s). The findings were statistically analyzed using an ANOVA 5%. All of the experimental groups were significantly different from the control group for both the compact and cancellous bone specimens. The compact bone specimens that received APDT treatment (for either 90, 180, or 300 s) showed reductions in the log10 CFU/ml of S. aureus by a magnitude of 4 log10. Cancellous bone specimens treated with 300 s of APDT showed the highest efficacy, and these specimens had a reduction in S. aureus CFU/ml by a factor of 3 log10. APDT treatment using these proposed parameters in combination with MG was effective at inactivating S. aureus biofilms in compact and cancellous bone specimens.

  9. Clinical Usefulness of Mandibular Reconstruction Using Custom-Made Titanium Mesh Tray and Autogenous Particulate Cancellous Bone and Marrow Harvested From Tibia and/or Ilia.

    PubMed

    Yamada, Hiroyuki; Nakaoka, Kazutoshi; Sonoyama, Tomoo; Kumagai, Kenichi; Ikawa, Tomoko; Shigeta, Yuko; Harada, Naohiko; Kawamura, Noboru; Ogawa, Takumi; Hamada, Yoshiki

    2016-05-01

    The objective of this study was to evaluate usefulness of mandibular reconstructions using custom-made titanium mesh (Ti-mesh) tray and particulate cancellous bone and marrow (PCBM). Consecutive 21 patients who underwent mandibular reconstruction were enrolled in this study. They were 13 men and 8 women (mean age, 52.0 years). Virtual reality simulation was performed using computer software based on the preoperative computed tomography data. A 3-dimensional skull model was constructed using 3-dimensional printer. A tray was custom-made from Ti-mesh sheet bent to adapt to the model. After PCBM harvesting from posterior ilia and/or proximal tibia, the tray was fixed to the host bone. New bone formation and configuration of the reconstructed mandible were assessed radiologically. Complications were recorded in each patient during the follow-up period. Patients' satisfaction with postoperative facial contour was evaluated using visual analog scale (VAS score, range, 0-100). In 16 of 21 patients, excellent new bone formation was recognized and expected results were radiologically achieved. In 5 patients, new bone formation was insufficient. Causes of insufficient bone formation included postoperative infection in 2 patients, Ti-mesh tray fracture in 2 patients, and local recurrence of lower gingival cancer in 1 patient. To prevent a tray fracture, a double-layered Ti-mesh tray was useful. Mean VAS score on patients' satisfaction was 77.1. Our results comprehensively suggest that mandibular reconstruction using custom-made Ti-mesh tray and PCBM is clinically useful. PMID:27092909

  10. Bone Growth and Turnover in Progesterone Receptor Knockout Mice

    PubMed Central

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

    2008-01-01

    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 microcomputed tomography analyses of bone from homozygous female PR knockout (PRKO) mice at 6, 12, and 26 wk 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 were normal in PRKO mice. In contrast, total, cancellous, and cortical bone mass were increased in the humerus of 12-wk-old PRKO mice, whereas cortical and cancellous bone mass in the tibia was normal. At 26 wk of age, cancellous bone area in the proximal tibia metaphysis of PRKO mice was 153% greater than age matched wild-type mice. The improved cancellous bone balance in 6-month-old 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 is not essential for bone growth and turnover. However, at some skeletal sites, PR signaling attenuates the accumulation of cortical and cancellous bone mass during adolescence. PMID:18276762

  11. Monte-Carlo approach to the microdosimetry of /sup 224/Ra in murine compact and cancellous bone

    SciTech Connect

    Humphreys, E.R.; Humm, J.L.

    1988-06-01

    A method is described which allows dose calculations to be made to individual target cells in different regions of mouse bone marrow exposed to alpha particles emitted from bone. The method takes into account the variable rate of transfer of energy along the tracks of alpha particles and was applied to experiment-based values calculated for the concentration of /sup 224/Ra on bone surfaces after an injection of a leukemogenic amount of the nuclide. These calculations show a minimum dose of 11 Gy in small (less than 50-micron) marrow spaces and 10 Gy close to bone surface in the shaft of the femur. The results suggest that leukemogenic doses are likely to occur at some distance from bone surfaces in wide marrow spaces and that osteosarcoma is not likely to be induced directly in cells immediately aligning bone surfaces.

  12. 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

    NASA Astrophysics Data System (ADS)

    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.

  13. The effects of nutrition and physical activity on bone development in male adolescents.

    PubMed

    Doğan, Muhsin; Derman, Orhan; Oksüz-Kanbur, Nuray; Akgül, Sinem; Kutluk, Tezer

    2009-01-01

    Peak bone mass (PBM) is defined as the highest bone mineral content (BMC) reached in any period of a person's life. The bone mass once gained at the peak begins to decline and continues to do so until the end of life. The aim of this study was to evaluate the relationship of nutrition and physical activity on bone mineralization during the adolescent period. The study took place at Hacettepe University Ihsan Doğramaci Children's Hospital Adolescent Unit. One hundred fourteen healthy male adolescents applying for different reasons, with ages ranging between 11.1 and 16.5 years, participated in the study. When all adolescents were evaluated, no statistical relationship between the daily calcium intake, BMC and bone mineral density (BMD) was obtained. However, a positive statistical relationship was found for those participants in Tanner stage I. This result is in support of previous studies stating the importance of calcium intake and bone mineralization in the prepubertal stage, suggested by our findings, which yielded a positive correlation only in the prepubertal stage. One of the reasons for the same effect not being observed in puberty is thought to be due to the hormonal changes and active role of sex steroids. This shows how critical the prepubertal period is for future bone health. During this critical period of prepuberty, the significance of nutritions and physical activity is evident.

  14. Practice of martial arts and bone mineral density in adolescents of both sexes

    PubMed Central

    Ito, Igor Hideki; Mantovani, Alessandra Madia; Agostinete, Ricardo Ribeiro; Costa, Paulo; Zanuto, Edner Fernando; Christofaro, Diego Giulliano Destro; Ribeiro, Luis Pedro; Fernandes, Rômulo Araújo

    2016-01-01

    Abstract Objective: The purpose of this study was to analyze the relationship between martial arts practice (judo, karate and kung-fu) and bone mineral density in adolescents. Methods: The study was composed of 138 (48 martial arts practitioners and 90 non-practitioners) adolescents of both sexes, with an average age of 12.6 years. Bone mineral density was measured using Dual-Energy X-ray Absorptiometry in arms, legs, spine, trunk, pelvis and total. Weekly training load and previous time of engagement in the sport modality were reported by the coach. Partial correlation tested the association between weekly training load and bone mineral density, controlled by sex, chronological age, previous practice and somatic maturation. Analysis of covariance was used to compare bone mineral density values according to control and martial arts groups, controlled by sex, chronological age, previous practice and somatic maturation. Significant relationships between bone mineral density and muscle mass were inserted into a multivariate model and the slopes of the models were compared using the Student t test (control versus martial art). Results: Adolescents engaged in judo practice presented higher values of bone mineral density than the control individuals (p-value=0.042; Medium Effect size [Eta-squared=0.063]), while the relationship between quantity of weekly training and bone mineral density was significant among adolescents engaged in judo (arms [r=0.308] and legs [r=0.223]) and kung-fu (arms [r=0.248] and spine [r=0.228]). Conclusions: Different modalities of martial arts are related to higher bone mineral density in different body regions among adolescents. PMID:27017002

  15. Prevalence of Periodontal Bone Loss in Brazilian Adolescents through Interproximal Radiography

    PubMed Central

    de Toledo, Benedicto Egbert Corrêa; Barroso, Eliane Marçon; Martins, Alex Tadeu; Zuza, Elizangela Partata

    2012-01-01

    Purpose. The aim of this study was to verify the prevalence of alveolar bone loss in Brazilian adolescents through the interproximal X-rays analysis. Methods. Bilateral and standardized interproximal (bitewing) X-rays were performed in 15-year-old adolescents (n = 326), and the processing of films and measurements of alveolar bone levels were accomplished by a single examiner. A distance between the cementoenamel junction (CEJ) and the alveolar bone crest more than 2 mm was considered as periodontal bone loss. Results. The results showed percentage of bone loss of 10.4% with predominance of horizontal defects (8.9%) over the vertical types (1.5%). It was verified higher individual distribution of one lesion (67.6%) than two (26.5%) or three lesions (5.6%), and higher occurrence was detected in men (14.95) than in women (8.21). Conclusion. It can be concluded that the interproximal radiography was an efficient method for the detection of alveolar bone loss, revealing low prevalence in adolescents and predominance of horizontal bone defects. PMID:23056048

  16. Cancellous bone of aged rats maintains its capacity to respond vigorously to the anabolic effects of prostaglandin E2 by modeling-dependent bone gain.

    PubMed

    Cui, L; Ma, Y F; Yao, W; Zhou, H; Setterberg, R B; Liang, T C; Jee, W S

    2001-01-01

    The present study examined the early effects of prostaglandin (PG)E2 on proximal tibial metaphyses of 20-month-old Wistar male rats. PGE, was given to intact rats for 10 and 30 days at 3mg/kg/day. After multiple in vivo fluorochrome labeling, undecalcified longitudinal sections were subjected to analysis of bone histomorphometry and classification of the contour of the cement line in bone formation units. The latter was used to classify bone formation units into modeling, remodeling and uncertain units. After 10 days of treatment, there was a 2% increase in woven bone formation with the appearance of osteoprogenitor cells and increases in the number of osteoblasts (649%) and osteoid (375%) surfaces. Remodeling and modeling units increased by 56% and 429%. respectively. After 30 days of treatment, there was an increase of 212% of total trabecular bone mass, 60% of which was woven bone. In addition, there were increases in labeling surface (147%), mineral apposition rate (760%), bone formation rates tissue area (BFR/T.Ar, 1920%; BFR/B.Pm, 343%), and bone turnover (BFR/B.Ar, 426%). Osteoblasts and osteoid production at 30 days were 29% and 58% less than at 10 days post-treatment. Modeling and remodeling activity did not differ from that seen at 10 days. In addition, PGE2 treatment tended to stimulate the closing of growth plates and decrease the fatty marrow area. We conclude that the aged skeleton was able to respond vigorously to PGE2 treatment. Massive osteoprogenitors cells, and osteoid and osteoblast formations were observed within 10 days. and dramatic woven and lamellar bone formation was seen at 30 days post-treatment. The anabolic effects were driven mainly by modeling.

  17. Accuracy of Cone Beam Computed Tomography, Photostimulable Phosphor Plate Digital Radiography and Conventional Radiography for Detection of Artificial Cancellous Bone Defects

    PubMed Central

    Bardal, Roghieh; Jahanihashemi, Hassan; Mostafavi, Maryam; Kalhor, Esmaeil; Tofangchiha, Maryam; Dehghani, Mahdieh

    2015-01-01

    Objectives: The optimal goal of radiography is to provide high-quality diagnostic images with the least patient radiation dose. The aim of this study was to evaluate the accuracy of cone-beam computed tomography (CBCT) and intraoral photostimulable phosphor plate (PSP) digital and film-based conventional radiography for detection of artificial cancellous bone defects. Materials and Methods: Five dry human mandibles were used in this study. The mandibles were placed inside a water bath made of plexiglass plates; then PSP and CBCT scans were obtained. The mandibles were cut by a coping saw in buccolingual dimension and oval defects measuring 6.1×6.1 mm, 3×6.1 mm and 4×4 mm were created by a milling machine in the spongy bone. After fixing the two parts together (buccal and lingual), radiographs were repeated. Presence or absence of defects on images was evaluated and recorded by the two observers. Using SPSS 16, compatibility level, sensitivity, specificity and receiver operating curve (ROC) analysis were determined for each observer. Results: The intraobserver agreement in all three imaging modalities was low to moderate (kappa≤0.613). The inter-observer agreement in all the three imaging modalities was moderate (kappa=0.406). The area under the curve (AUC) of the imaging modalities in each observation was not significantly different. The area under the curve based on defect size for the two observers was not significantly different either. Conclusion: Defects confined to spongy bone can be identified on film and PSP radiographs and CBCT scans. However, interpretation of PSP images and CBCT scans needs greater expertise and skills. PMID:27507990

  18. The effect of in situ/in vitro three-dimensional quantitative computed tomography image voxel size on the finite element model of human vertebral cancellous bone.

    PubMed

    Lu, Yongtao; Engelke, Klaus; Glueer, Claus-C; Morlock, Michael M; Huber, Gerd

    2014-11-01

    Quantitative computed tomography-based finite element modeling technique is a promising clinical tool for the prediction of bone strength. However, quantitative computed tomography-based finite element models were created from image datasets with different image voxel sizes. The aim of this study was to investigate whether there is an influence of image voxel size on the finite element models. In all 12 thoracolumbar vertebrae were scanned prior to autopsy (in situ) using two different quantitative computed tomography scan protocols, which resulted in image datasets with two different voxel sizes (0.29 × 0.29 × 1.3 mm(3) vs 0.18 × 0.18 × 0.6 mm(3)). Eight of them were scanned after autopsy (in vitro) and the datasets were reconstructed with two voxel sizes (0.32 × 0.32 × 0.6 mm(3) vs. 0.18 × 0.18 × 0.3 mm(3)). Finite element models with cuboid volume of interest extracted from the vertebral cancellous part were created and inhomogeneous bilinear bone properties were defined. Axial compression was simulated. No effect of voxel size was detected on the apparent bone mineral density for both the in situ and in vitro cases. However, the apparent modulus and yield strength showed significant differences in the two voxel size group pairs (in situ and in vitro). In conclusion, the image voxel size may have to be considered when the finite element voxel modeling technique is used in clinical applications.

  19. Bone Characteristics and Their Determinants in Adolescents and Young Adults with Early-Onset Severe Obesity.

    PubMed

    Viljakainen, H T; Valta, H; Lipsanen-Nyman, M; Saukkonen, T; Kajantie, E; Andersson, S; Mäkitie, O

    2015-10-01

    Childhood obesity is associated with compromised bone health. We studied bone characteristics and their determinants in obese young adults. The study included 68 subjects with early-onset severe obesity and 73 normal-weight controls. Data on physical activity (PA), diet and smoking were collected. Bone characteristics were measured using peripheral QCT. The obese and control subjects were similar in age (mean 19.6 ± 2.6 years) and height but BMIs differed (39.7 and 22.6 kg/m(2)). A clustering of unhealthy lifestyles was marked: Obese subjects reported less supervised PA in childhood, adolescence and currently (p < 0.03) and were more likely to smoke (p = 0.005), and had a lower healthy eating index (HEI) (p = 0.007) but similar alcohol consumption compared with controls. In obese women, all crude bone characteristics were higher than in controls; in men, the differences were smaller. Associations of lifestyle factors with bone characteristics were tested using partial correlations. Independently of BMI, supervised PA in adolescence and alcohol consumption were related positively to bone characteristics in both groups. HEI associated positively with bone characteristics only in controls, while smoking was a positive determinant of bone characteristics only in obese subjects. The multivariate model showed that the contribution of lifestyle factors to bone characteristics was minimal compared with BMI. Early-onset obesity is accompanied by poor dietary quality, sedentary lifestyle, and more frequent smoking, but the overall contribution of these lifestyle factors to bone strength is limited. Bone strength is more likely to be compromised in men and in unloaded bone sites in subjects with early-onset severe obesity. The impact of obesity-related endocrine changes on bone characteristics need to be evaluated in future studies.

  20. Relationship between bone mineral density, leptin and insulin concentration in Brazilian obese adolescents.

    PubMed

    do Prado, Wagner Luiz; de Piano, Aline; Lazaretti-Castro, Marise; de Mello, Marco Túlio; Stella, Sérgio Garcia; Tufik, Sergio; do Nascimento, Cláudia Maria Oller; Oyama, Lila Missae; Lofrano, Mara Cristina; Tock, Lian; Caranti, Danielle Arisa; Dâmaso, Ana Raimunda

    2009-01-01

    Despite the epidemic of adolescent obesity, the effect of obesity and hormones on bone mineral accrual during growth is poorly understood. Studies using dual-energy X-ray to examine the effect of obesity on bone mass in children and adolescents have yielded conflicting results. The aim of this study was to explore the combined and independent contributions of body mass index, body composition, leptin, insulin, glucose levels and Homeostasis Model Assessment Insulin Resistance (HOMA-IR) to bone mineral density (BMD) and bone mineral content in a group of Brazilian obese adolescents. This study included 109 post-pubescent obese adolescents. A whole-body dual-energy X-ray absorptiometry scan was performed,using a HOLOGIC QDR4200, to determine whole-body BMD and body composition. Blood samples were collected in the outpatient clinic after an overnight fast, and evaluated for fasting blood glucose and immunoreactive insulin. Leptin levels were assessed with a radioimmunoassay kit. Insulin resistance was assessed by HOMA-IR and the quantitative insulin sensitivity check index. Our results showed that insulin levels and HOMA-IR correlated negatively with BMD and a linear regression analysis showed that serum leptin is inversely associated to BMD adjusted for body mass. In conclusion, our data support the hypothesis that leptin, insulin and HOMA-IR are inversely associated with BMD and play a significant direct role in bone metabolism. PMID:19466592

  1. Low bone mass in behaviorally HIV-infected young men on antiretroviral therapy: adolescent trials network (ATN) study 021B

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peak bone mass is achieved in adolescence/early adulthood and is the key determinant of bone mass in adulthood. We evaluated the association of bone mass with HIV infection and antiretroviral therapy (ART) during this critical period among behaviorally HIV infected young men and seronegative control...

  2. Numerical description and experimental validation of a rheology model for non-Newtonian fluid flow in cancellous bone.

    PubMed

    Widmer Soyka, René P; López, Alejandro; Persson, Cecilia; Cristofolini, Luca; Ferguson, Stephen J

    2013-11-01

    Fluids present or used in biology, medicine and (biomedical) engineering are often significantly non-Newtonian. Furthermore, they are chemically complex and can interact with the porous matrix through which they flow. The porous structures themselves display complex morphological inhomogeneities on a wide range of length scales. In vertebroplasty, a shear-thinning fluid, e.g. poly(methyl methacrylate) (PMMA), is injected into the cavities of vertebral trabecular bone for the stabilization of fractures and metastatic lesions. The main objective of this study was therefore to provide a protocol for numerically investigating the rheological properties of PMMA-based bone cements to predict its spreading behavior while flowing through vertebral trabecular bone. A numerical upscaling scheme based on a dimensionless formulation of the Navier-Stokes equation is proposed in order to relate the pore-scale rheological properties of the PMMA that were experimentally estimated using a plate rheometer, to the continuum-scale. On the pore length scale, a viscosity change on the order of one magnitude was observed whilst the shear-thinning properties caused a viscosity change on the order of only 10% on the continuum length scale and in a flow regime that is relevant for vertebroplasty. An experimental validation, performed on human cadaveric vertebrae (n=9), showed a significant improvement of the cement spreading prediction accuracy with a non-Newtonian formulation. A root mean square cement surface prediction error of 1.53mm (assuming a Newtonian fluid) and 1.37mm (assuming a shear-thinning fluid) was found. Our findings highlight the importance of incorporating the non-Newtonian fluids properties in computational models of porous media at the appropriate length scale. PMID:23867293

  3. Numerical description and experimental validation of a rheology model for non-Newtonian fluid flow in cancellous bone.

    PubMed

    Widmer Soyka, René P; López, Alejandro; Persson, Cecilia; Cristofolini, Luca; Ferguson, Stephen J

    2013-11-01

    Fluids present or used in biology, medicine and (biomedical) engineering are often significantly non-Newtonian. Furthermore, they are chemically complex and can interact with the porous matrix through which they flow. The porous structures themselves display complex morphological inhomogeneities on a wide range of length scales. In vertebroplasty, a shear-thinning fluid, e.g. poly(methyl methacrylate) (PMMA), is injected into the cavities of vertebral trabecular bone for the stabilization of fractures and metastatic lesions. The main objective of this study was therefore to provide a protocol for numerically investigating the rheological properties of PMMA-based bone cements to predict its spreading behavior while flowing through vertebral trabecular bone. A numerical upscaling scheme based on a dimensionless formulation of the Navier-Stokes equation is proposed in order to relate the pore-scale rheological properties of the PMMA that were experimentally estimated using a plate rheometer, to the continuum-scale. On the pore length scale, a viscosity change on the order of one magnitude was observed whilst the shear-thinning properties caused a viscosity change on the order of only 10% on the continuum length scale and in a flow regime that is relevant for vertebroplasty. An experimental validation, performed on human cadaveric vertebrae (n=9), showed a significant improvement of the cement spreading prediction accuracy with a non-Newtonian formulation. A root mean square cement surface prediction error of 1.53mm (assuming a Newtonian fluid) and 1.37mm (assuming a shear-thinning fluid) was found. Our findings highlight the importance of incorporating the non-Newtonian fluids properties in computational models of porous media at the appropriate length scale.

  4. Adolescence: How do we increase intestinal calcium absorption to allow for bone mineral mass accumulation?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An increase in calcium absorptive efficiency (fractional absorption of dietary calcium) during adolescence is associated with a rapid increase in total body bone mineral mass (BMM) accumulation. This increase occurs across a range of calcium intakes. It appears to be principally mediated by hormonal...

  5. Calcium and vitamin D requirements for optimal bone mass during adolescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There remains very strong interest in the calcium and vitamin D requirements of adolescents related to bone health. The Institute of Medicine (IOM) released new dietary guidelines in late 2010 for these nutrients. These guidelines were primarily based on literature published in 2009 and earlier and ...

  6. Effects of Life-long Fluoride Intake on Bone Measures of Adolescents

    PubMed Central

    Levy, S.M.; Warren, J.J.; Phipps, K.; Letuchy, E.; Broffitt, B.; Eichenberger-Gilmore, J.; Burns, T.L.; Kavand, G.; Janz, K.F.; Torner, J.C.; Pauley, C.A.

    2014-01-01

    Controversy persists concerning the impact of community water fluoridation on bone health in adults, and few studies have assessed relationships with bone at younger ages. Ecological studies of fluoride’s effects showed some increase in bone mineral density of adolescents and young adults in areas with fluoridated water compared with non-fluoridated areas. However, none had individual fluoride exposure measures. To avoid ecological fallacy and reduce bias, we assessed associations of average daily fluoride intake from birth to age 15 yr for Iowa Bone Development Study cohort members with age 15 yr dual-energy x-ray absorptiometry (DXA) bone outcomes (whole body, lumbar spine, and hip), controlling for known determinants (including daily calcium intake, average daily time spent in moderate-to-vigorous intensity physical activity, and physical maturity). Mean (SD) daily fluoride intake was 0.66 mg (0.24) for females and 0.78 mg (0.30) for males. We found no significant relationships between daily fluoride intake and adolescents’ bone measures in adjusted models (for 183 females, all p values ≥ .10 and all partial R2 ≤ 0.02; for 175 males, all p values ≥ .34 and all partial R2 ≤ 0.01). The findings suggest that fluoride exposures at the typical levels for most US adolescents in fluoridated areas do not have significant effects on bone mineral measures. PMID:24470542

  7. Vitamin-D nutrition and bone mass in adolescent black girls.

    PubMed Central

    Talwar, Sonia A.; Swedler, Jane; Yeh, James; Pollack, Simcha; Aloia, John F.

    2007-01-01

    OBJECTIVE: To examine the relationship between bone mass and serum levels of 25-hydroxyvitamin D and parathyroid hormone in African-American adolescent girls. STUDY DESIGN: A cross-sectional sample at a suburban research center. METHODS: Twenty-one adolescent black girls 12-14 years of age, were studied during winter with biochemical measurements of serum 25-hydroxyvitamin D (25-OHD) and parathyroid hormone (PTH). Bone mass assessment was done with dual energy x-ray absorbsiometry (DXA) and peripheral quantitative computed tomography of the radius (p-QCT). Anthropometric, physical activity and nutritional data were collected. RESULTS: All participants were vitamin-D deficient (serum 25-OHD level <50 nmol/L), of whom nine (43%) were severely vitamin-D deficient (serum 25-OHD level <20 nmol/L). Mean daily intake of dietary calcium was 540 mg/d and vitamin D was 195 IU/d. There was a positive correlation, although statistically not significant, between serum 25-OHD and various bone mass measurements. Serum PTH was inversely correlated to total body BMD (r = -0.51, p = 0.02) and other bone mineral density at the lumbar spine, total femur and mid-radius. CONCLUSION: Vitamin-D insufficiency is a widely prevalent problem among adolescent African-American girls. Our data implies that enhancing vitamin-D nutrition resulting in lower serum PTH levels could potentially influence their peak bone mass. PMID:17595934

  8. Body mass is the primary determinant of midfemoral bone acquisition during adolescent growth.

    PubMed

    Moro, M; van der Meulen, M C; Kiratli, B J; Marcus, R; Bachrach, L K; Carter, D R

    1996-11-01

    To study the determinants of bone mass and structure during adolescence, we analyzed the femoral mid-diaphysis of 375 healthy adolescents and young adults, ages 9-26 years, from four ethnic cohorts (African-American, Asian-American, Caucasian, and Hispanic). Whole-body dual-energy X-ray absorptiometry (DXA) scans were used to determine diaphyseal length and mid-diaphyseal diameter of the left femur, as well as linear bone mineral content (BMCL) of a region at the mid-diaphysis. Cross-sectional geometric properties were estimated and used to calculate two structural strength indicators: the section modulus and the whole bone strength index. When the relationships between the bone measurements and age, pubertal group, height, or body mass were evaluated, all cross-sectional femoral measures correlated most strongly with body mass. Multiple regressions accounting for gender and ethnicity provided little additional predictive value over the simple regressions with body mass alone. Furthermore, accounting for all developmental parameters (age, pubertal group, body mass, lean body mass, calcium intake, physical activity level) as well as ethnicity and gender in a single saturated model also did not generally significantly improve the predictive results achieved using only body mass. Our results indicate that increases in midfemoral bone mass and cross-sectional properties during adolescence are primarily related to increases in mechanical loading as reflected by body mass.

  9. The Relationship between Physical Activity and Bone during Adolescence Differs according to Sex and Biological Maturity.

    PubMed

    Weeks, Benjamin K; Beck, Belinda R

    2010-01-01

    This study examines the relationships between bone mass, physical activity, and maturational status in healthy adolescent boys and girls. Methods. Ninety-nine early high-school (Year 9) students were recruited. Physical activity and other lifestyle habits were recorded via questionnaire. Anthropometrics, muscle power, calcaneal broadband ultrasound attenuation (BUA), bone mineral content (BMC), and lean tissue mass were measured. Maturity was determined by Tanner stage and estimated age of peak height velocity (APHV). Results. Boys had greater APHV, weight, height, muscle power, and dietary calcium than girls (P < .05). Boys exhibited greater femoral neck BMC and trochanteric BMC while girls had higher BUA and spine BMAD (P < .05). Physical activity and vertical jump predicted BMAD and BUA most strongly for boys whereas years from APHV were the strongest predictor for girls. Conclusion. Sex-specific relationships exist between physical activity, maturity and bone mass during adolescence.

  10. Bone health in children and adolescents with perinatal HIV infection

    PubMed Central

    Puthanakit, Thanyawee; Siberry, George K

    2013-01-01

    The long-term impact on bone health of lifelong HIV infection and prolonged ART in growing and developing children is not yet known. Measures of bone health in youth must be interpreted in the context of expected developmental and physiologic changes in bone mass, size, density and strength that occur from fetal through adult life. Low bone mineral density (BMD) appears to be common in perinatally HIV-infected youth, especially outside of high-income settings, but data are limited and interpretation complicated by the need for better pediatric norms. The potential negative effects of tenofovir on BMD and bone mass accrual are of particular concern as this drug may be used more widely in younger children. Emphasizing good nutrition, calcium and vitamin D sufficiency, weight-bearing exercise and avoidance of alcohol and smoking are effective and available approaches to maintain and improve bone health in all settings. More data are needed to inform therapies and monitoring for HIV-infected youth with proven bone fragility. While very limited data suggest lack of marked increase in fracture risk for youth with perinatal HIV infection, the looming concern for these children is that they may fail to attain their expected peak bone mass in early adulthood which could increase their risk for fractures and osteoporosis later in adulthood. PMID:23782476

  11. Exercise training, menstrual irregularities and bone development in children and adolescents.

    PubMed

    Eliakim, Alon; Beyth, Yoram

    2003-08-01

    Weight bearing physical activity plays an important role in bone development. This is particularly important in children and adolescents since bone mineral density reaches about 90% of its peak by the end of the second decade, and because about one quarter of adult bone is accumulated during the two years surrounding the peak bone growth velocity. Recent studies suggested that the exercise-induced increase in bone mineralization is maturity dependent, and that there is a "window of opportunity" and a critical period for bone response to weight bearing exercise during early puberty and premenarchal years. This supports the idea that increase in physical activity during childhood and adolescence can prevent bone disorders (like osteoporosis) later in life. In contrast, strenuous physical activity may affect the female reproductive system and lead to "athletic amenorrhea". The prevalence of "athletic amenorrhea" is 4-20 times higher than the general population. As a consequence, bone demineralization may develop with increased risk of skeletal fragility, fractures, vertebral instability, and curvature. Menstrual abnormalities in the female athlete result from hypothalamic suppression of the spontaneous pulsatile secretion of gonadotropin releasing hormone. Recent studies suggested that reduced energy availability (increased energy expenditure with inadequate caloric intake) is the main cause of the central suppression of the hypothalamic pituitary-gonadal axis. Therefore, effort should be made to optimize the nutritional state of female athletes, and if not successful, to reduce the training load in order to prevent menstrual abnormalities, and deleterious bone effects in particular during the critical period of rapid bone growth.

  12. Aerobic plus resistance training improves bone metabolism and inflammation in adolescents who are obese.

    PubMed

    Campos, Raquel M S; de Mello, Marco T; Tock, Lian; Silva, Patrícia L; Masquio, Deborah C L; de Piano, Aline; Sanches, Priscila L; Carnier, June; Corgosinho, Flávia C; Foschini, Denis; Tufik, Sergio; Dâmaso, Ana R

    2014-03-01

    Obesity is a worldwide epidemic with a high prevalence of comorbidities, including alterations in bone mineral metabolism. The purpose of this yearlong study was to evaluate the role of 2 types of exercise training (aerobic and aerobic plus resistance exercise) on adipokines parameters and bone metabolism in adolescents who are obese. This was a clinical trial study with interdisciplinary weight loss therapy. Forty-two postpubertal adolescents who are obese were subjected to interdisciplinary weight loss therapy with physical exercise, medical monitoring, nutritional intervention, and psychological intervention. Data were collected from serum analyses of leptin, ghrelin, adiponectin, glucose, and insulin. Anthropometric measurements of body composition, bone mineral density, visceral, and subcutaneous fat were also performed. Statistical tests were applied using repeated-measures analysis of variance. Correlations were established using the Pearson test, and dependencies of variables were established using simple linear regression test. Both training types promoted reductions in body mass index, total central, visceral and subcutaneous fat, insulin concentration, and homeostasis model assessment insulin resistance (HOMA-IR) index, but only aerobic plus resistance training showed statistical improvements in the bone mineral content, adiponectin concentration, and lean tissue. Effective reduction in the visceral/subcutaneous ratio, central/peripheral ratio, and leptin concentration was observed. Insulin and the HOMA-IR index were negative predictors of bone mineral content in the combined training group. Moreover, fat distribution was a negative predictor for bone mineral density in both groups. Aerobic plus resistance training promotes a protective role in bone mineral content associated with an improvement in adiponectin and leptin concentrations, favoring the control of the inflammatory state related to obesity in adolescents. Aerobic plus resistance training

  13. Aerobic plus resistance training improves bone metabolism and inflammation in adolescents who are obese.

    PubMed

    Campos, Raquel M S; de Mello, Marco T; Tock, Lian; Silva, Patrícia L; Masquio, Deborah C L; de Piano, Aline; Sanches, Priscila L; Carnier, June; Corgosinho, Flávia C; Foschini, Denis; Tufik, Sergio; Dâmaso, Ana R

    2014-03-01

    Obesity is a worldwide epidemic with a high prevalence of comorbidities, including alterations in bone mineral metabolism. The purpose of this yearlong study was to evaluate the role of 2 types of exercise training (aerobic and aerobic plus resistance exercise) on adipokines parameters and bone metabolism in adolescents who are obese. This was a clinical trial study with interdisciplinary weight loss therapy. Forty-two postpubertal adolescents who are obese were subjected to interdisciplinary weight loss therapy with physical exercise, medical monitoring, nutritional intervention, and psychological intervention. Data were collected from serum analyses of leptin, ghrelin, adiponectin, glucose, and insulin. Anthropometric measurements of body composition, bone mineral density, visceral, and subcutaneous fat were also performed. Statistical tests were applied using repeated-measures analysis of variance. Correlations were established using the Pearson test, and dependencies of variables were established using simple linear regression test. Both training types promoted reductions in body mass index, total central, visceral and subcutaneous fat, insulin concentration, and homeostasis model assessment insulin resistance (HOMA-IR) index, but only aerobic plus resistance training showed statistical improvements in the bone mineral content, adiponectin concentration, and lean tissue. Effective reduction in the visceral/subcutaneous ratio, central/peripheral ratio, and leptin concentration was observed. Insulin and the HOMA-IR index were negative predictors of bone mineral content in the combined training group. Moreover, fat distribution was a negative predictor for bone mineral density in both groups. Aerobic plus resistance training promotes a protective role in bone mineral content associated with an improvement in adiponectin and leptin concentrations, favoring the control of the inflammatory state related to obesity in adolescents. Aerobic plus resistance training

  14. Major depressive disorder and bone mass in adolescents and young adults.

    PubMed

    Calarge, Chadi A; Butcher, Brandon D; Burns, Trudy L; Coryell, William H; Schlechte, Janet A; Zemel, Babette S

    2014-10-01

    Depression has been associated with reduced bone mass in adults, but the mechanisms remain unclear. In addition, little is known about the association between depression and bone health during growth and development. To address this knowledge gap, we examined bone density and structure in 222 adolescents and young adults (69% females, mean ± SD age: 19.0 ± 1.5 years), enrolled within 1 month of starting a selective serotonin reuptake inhibitor (SSRI) or unmedicated. Psychiatric functioning was assessed with self-report and researcher-administered instruments, including the Longitudinal Interval Follow-up Evaluation for Adolescents (A-LIFE). Anthropometric and laboratory measures included dual-energy x-ray absorptiometry and peripheral quantitative computed tomography scans. Linear multivariable regression analysis tested the association between depression and bone mass, after accounting for relevant confounders. The presence of current depression was associated with a significant reduction in age-sex-height-race-specific bone mineral density (BMD) and content (BMC) of total body less head and lumbar spine. The findings varied by assessment method with self-report scales, capturing symptom severity over the prior week or two, yielding the weakest associations. Depression was also associated with reduced cortical thickness and a trend for increased endosteal circumference. In contrast, generalized anxiety disorder was not associated with bone deficits. In sum, depressive illness is associated with significantly lower bone mass in youths. Future investigations must examine whether bone recovery is possible following depression remission or whether remedial interventions are warranted to optimize bone mass in order to minimize the long-term risk of osteoporosis.

  15. Bone growth and turnover in progesterone receptor knockout mice.

    SciTech Connect

    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.

  16. Clinical and biochemical determinants of bone metabolism and bone mass in adolescent female patients with anorexia nervosa.

    PubMed

    Audí, Laura; Vargas, Deisi M; Gussinyé, Miquel; Yeste, Diego; Martí, Gertrudis; Carrascosa, Antonio

    2002-04-01

    Among pathologies prevalent in western societies, anorexia nervosa has increased over the last decade. Its effects on bone mass need to be defined, and prognostic factors, either clinical or biochemical, could aid clinicians in individual patient management. To determine which clinical and/or biochemical parameters could be related to bone mass status in adolescent female anorexia nervosa patients, 73 female patients were classified according to different stages of their illness and studied in terms of clinical and biochemical parameters and bone densitometric mineral content at lumbar spine. Patients (age 17.2 +/- 1.7 y, mean +/- SD) with Tanner pubertal stage 5, regular menstruation for more than 3 mo before the onset of secondary amenorrhea, and diagnosed with anorexia nervosa were consecutively studied and classified in three clinical situations: I) active phase (34 patients): undernourished and amenorrheic; II) weight recovered but still amenorrheic (20 patients); III) fully recovered (19 patients). Clinical data were recorded at the time of bone density measurement, concomitant with blood sample extraction for study of IGF-I, IGF-binding protein 3 (IGFBP-3), IGFBP-1, estradiol, sex hormone-binding globulin, dehydroepiandrosterone sulfate, prealbumin, amino-terminal propeptide of procollagen III, osteocalcin, bone alkaline phosphatase, carboxy-terminal propeptide of procollagen I, amino-terminal propeptide of procollagen I, carboxy-terminal telopeptide of collagen I, 25-OH-vitamin D, 1,25(OH)(2)-vitamin D, and parathormone. In addition, a 24-h urine collection was made for cortisol, GH, deoxypyridinoline, amino-terminal telopeptide of collagen I, and calcium and creatinine content analysis. IGF-I, estradiol, and biochemical bone formation markers were higher and IGFBP-1, sex hormone-binding globulin, and biochemical bone resorption markers were lower in the weight-recovered stages (stages II and III) compared with the active phase (stage I). Bone formation

  17. Potential of centrifugal seeding method in improving cells distribution and proliferation on demineralized cancellous bone scaffolds for tissue-engineered meniscus.

    PubMed

    Zhang, Zheng-Zheng; Jiang, Dong; Wang, Shao-Jie; Qi, Yan-Song; Zhang, Ji-Ying; Yu, Jia-Kuo

    2015-07-22

    Tissue-engineered meniscus offers a possible solution to the regeneration and replacement problem of meniscectomy. However, the nonuniform distribution and declined proliferation of seeded cells on scaffolds hinder the application of tissue-engineered meniscus as a new generation of meniscus graft. This study systematically investigated the performances of different seeding techniques by using the demineralized cancellous bone (DCB) as the scaffold. Static seeding, injection seeding, centrifugal seeding, and vacuum seeding methods were used to seed the meniscal fibrochondrocytes (MFCs) and mesenchymal stem cells (MSCs) to scaffolds. Cell-binding efficiency, survival rate, distribution ability, and long-term proliferation effects on scaffolds were quantitatively evaluated. Cell adhesion was compared via cell-binding kinetics. Cell viability and morphology were assessed by using fluorescence staining. Combined with the reconstructed three-dimensional image, the distribution of seeded cells was investigated. The Cell Counting Kit-8 assay and DNA assay were employed to assess cell proliferation. Cell-binding kinetics and cell survival of the MFCs were improved via centrifugal seeding compared to injection or vacuum seeding methods. Seeded MFCs by centrifugation showed a more homogeneous distribution throughout the scaffold than cells seeded by other methods. Moreover, the penetration depth in the scaffold of seeded MFCs by centrifugation was 300-500 μm, much higher than the value of 100-300 μm by the surface static and injection seeding. The long-term proliferation of the MFCs in the centrifugal group was also significantly higher than that in the other groups. The results of the MSCs were similar to those of the MFCs. The centrifugal seeding method could significantly improve MFCs or MSCs distribution and proliferation on the DCB scaffolds, thus providing a simple, cost-effective, and effective cell-seeding protocol for tissue-engineered meniscus.

  18. Combat sports practice favors bone mineral density among adolescent male athletes.

    PubMed

    Nasri, Raouf; Hassen Zrour, Saoussen; Rebai, Haithem; Neffeti, Fadoua; Najjar, Mohamed Fadhel; Bergaoui, Naceur; Mejdoub, Hafedh; Tabka, Zouhair

    2015-01-01

    The aim of this study was to determine the impact of combat sports practice on bone mineral density (BMD) and to analyze the relationship between bone parameters and anthropometric measurements, bone markers, and activity index (AI). In other words, to detect the most important determinant of BMD in the adolescent period among combat sports athletes. Fifty athletes engaged in combat sports, mean age 17.1±0.2 yr, were compared with 30 sedentary subjects who were matched for age, height, and pubertal stage. For all subjects, the whole-body BMD, lumbar spine BMD (L2-L4), and BMD in the pelvis, arms, and legs was measured by dual-energy X-ray absorptiometry, and anthropometric measurements were evaluated. Daily calcium intake, bone resorption, and formation markers were measured. BMD measurements were greater in the combat sports athletes than in the sedentary group (p<0.01). Weight, body mass index, and lean body mass were significantly correlated with BMD in different sites. Daily calcium consumption lower than daily calcium intake recommended in both athletes and sedentary group. AI was strongly correlated with all BMD measurements particularly with the whole body, legs, and arms. Negative correlations were observed between bone markers and BMD in different sites. The common major predictor of BMD measurements was AI (p<0.0001). AI associated to lean body mass determined whole-body BMD until 74%. AI explained both BMD in arms and L2-L4 at 25%. AI associated to height can account for 63% of the variance in BMD legs. These observations suggested that the best model predicting BMD in different sites among adolescent combat sports athletes was the AI. Children and adolescents should be encouraged to participate in combat sports to maximize their bone accrual. PMID:24176431

  19. Increasing fluid milk favorably affects bone mineral density responses to resistance training in adolescent boys.

    PubMed

    Volek, Jeff S; Gómez, Ana L; Scheett, Timothy P; Sharman, Matthew J; French, Duncan N; Rubin, Martyn R; Ratamess, Nicholas A; McGuigan, Michael M; Kraemer, William J

    2003-10-01

    This study examined the effects of increasing milk on bone and body composition responses to resistance training in adolescents. Twenty-eight boys (13 to 17 years of age) were randomly assigned to consume, in addition to their habitual diet, 3 servings/day of 1% fluid milk (n=14) or juice not fortified with calcium (n=14) while engaged in a 12-week resistance-training program. For all subjects combined, there were significant (Pbone mineral content (+3.6%), bone mineral density (+1.8%), and maximal strength in the squat (+43%) and bench press (+23%). Compared with juice, the milk group had a significantly greater increase in bone mineral density (0.014 vs 0.028 g/cm(2)). Increasing intake of milk in physically active adolescent boys may enhance bone health.

  20. Condylar subchondral formation of cortical bone in adolescents and young adults.

    PubMed

    Lei, Jie; Liu, Mu-Qing; Yap, Adrian U Jin; Fu, Kai-Yuan

    2013-01-01

    We investigated subchondral formation of cortical bone in the condyles of adolescents and young adults, and looked for age-related and sex-related differences in bony formation with the aid of cone-beam computed tomography data in 1438 subjects aged between 10 and 30 years. The scans were part of the hospital's clinical protocol for patients seeking orthodontic or orthognathic treatment. No patient had signs or symptoms of temporomandibular disorders. Central images of the coronal and sagittal planes of the condyle were acquired and scored. Subchondral formation of cortical bone was seen as a high-density compact linear image, and subjects were classified into complete, partial, and no formation. Subchondral formation of cortical bone was first seen at the ages of 13-14 in boys and 12-13 in girls. Complete cortical bony formation was seen after the age of 22 years for men and 21 for women. We conclude that cortical bone begins to form around the periphery of the condyles during adolescence (12-14 years). A continuous, homogeneous, and compact cortical bony layer is established in young adults by the age of 21-22, indicating full development of the mandibular condyle. The condylar bone developed gradually and was generally fully developed a year earlier in women than men.

  1. Giant cell tumor of bone in children and adolescents.

    PubMed

    Hoeffel, J C; Galloy, M A; Grignon, Y; Chastagner, P; Floquet, J; Mainard, L; Kadiri, R

    1996-10-01

    Giant cell tumor of bone rarely affects children, in whom it is usually located in a metaphysis in contrast to the predominantly epiphyseal localization in adults. Five cases are reported, two at the femur, two at the fibula and one at the tibia. Plain film radiography and computed tomography are the most informative imaging studies. The differential diagnosis is with aneurysmal bone cyst and, in metaphyseal-epiphyseal forms, with chondroblastoma. Treatment usually consists in curettage of the tumor followed by filling of the cavity; however, more extensive resection is required in some cases. PMID:8938873

  2. [Bone and joint diseases in children. Adequate calcium intake and dietary habit especially breakfast in children and adolescents].

    PubMed

    Kodama, Momoko; Uenishi, Kazuhiro

    2010-06-01

    Childhood and adolescence are important periods for body growth. Calcium is one of the critical dietary factors especially for bone growth. Although recommended dietary allowance (RDA) of calcium has been determined higher in Dietary reference intakes for Japanese, 2010, calcium intake of Japanese children and adolescent are not necessarily adequate. Furthermore, breakfast skippers in this period tend to increase. So, it is very important to acquire an adequate dietary habit from childhood and adolescent. PMID:20513944

  3. Porcine skin gelatin hydrolysate promotes longitudinal bone growth in adolescent rats.

    PubMed

    Leem, Kang-Hyun; Lee, Sena; Jang, Aera; Kim, Hye Kyung

    2013-05-01

    Collagen hydrolysates (CHs) are mixtures of peptides obtained by partial hydrolysis of gelatin that are receiving scientific attention as potential oral supplements for the restoration of osteoarticular tissues. The aim of this study was to evaluate the effectiveness of CHs for promoting longitudinal bone growth in growing rats. An in vitro study was carried out in osteoblast-like MG63 cells and the most effective CH on bone formation was selected among 36 various CHs. An in vivo study confirmed the functional effects of a selected CH with molecular weight of <3 kDa on longitudinal bone growth. CHs dose-dependently promoted the longitudinal bone growth and height of the growth plate in adolescent male rats, whereas gelatin failed to affect longitudinal bone growth. Insulin-like growth factor-1 and bone morphogenetic protein-2 in the CH treated group were highly expressed in the growth plate. These results suggest that CHs isolated in this study may provide beneficial effects on bone metabolism of growing animals and humans. PMID:23631489

  4. Nutritional issues in adolescents after bone marrow transplant: a literature review.

    PubMed

    Rodgers, Cheryl; Walsh, Teresa

    2008-01-01

    Bone marrow transplantation and related complications can cause gastrointestinal (GI) side effects that can lead to poor nutrition, which has been associated with several morbidity and mortality issues. Adolescents require adequate nutrition not only to maintain health but to advance with normal growth and development. This article synthesizes the bone marrow transplant (BMT) literature regarding adolescents' nutritional needs, etiologies of altered oral intake, GI symptoms, nutritional assessments, nutritional interventions, and quality of life associated with poor nutrition. In addition, gaps in knowledge in the literature are identified. To provide effective and thorough care to patients during their BMT recovery, the knowledge base of nutritional and eating issues after transplant needs to become more comprehensive. Nurses play an important role in gathering and reporting clinical information. By anticipating potential risk factors, assessing and identifying symptoms, and initiating appropriate interventions promptly, patients can experience a more positive BMT experience.

  5. Motor Competence in Early Childhood Is Positively Associated With Bone Strength in Late Adolescence

    PubMed Central

    Sayers, Adrian; Deere, Kevin C; Emond, Alan; Tobias, Jon H

    2016-01-01

    ABSTRACT The onset of walking in early childhood results in exposure of the lower limb to substantial forces from weight bearing activity that ultimately contribute to adult bone strength. Relationships between gross motor score (GMS), at 18 months and bone outcomes measured at age 17 years were examined in 2327 participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Higher GMS indicated greater motor competence in weight‐bearing activities. Total hip bone mineral density (BMD) and hip cross‐sectional moment of inertia (CSMI) were assessed from dual‐energy X‐ray absorptiometry (DXA). Bone measures including cortical bone mineral content (BMC), periosteal circumference (PC), cortical thickness (CT), cortical bone area (CBA), cortical BMD (BMDC) and cross‐sectional moment of inertia (CSMI) were assessed by peripheral quantitative computed tomography (pQCT) at 50% distal‐proximal length. Before adjustment, GMS was associated with hip BMD, CSMI, and tibia BMC, PC, CT, CBA and CSMI (all p < 0.001) but not BMDC (p > 0.25). Strongest associations (standardized regression coefficients with 95% CI) were between GMS and hip BMD (0.086; 95% CI, 0.067 to 0.105) and tibia BMC (0.105; 95% CI, 0.089 to 0.121). With the exception of hip BMD, larger regression coefficients were observed in males (gender interactions all p < 0.05). Adjustment for lean mass resulted in substantial attenuation of regression coefficients, suggesting associations between impaired motor competence and subsequent bone development are partly mediated by alterations in body composition. In conclusion, impaired motor competence in childhood is associated with lower adolescent bone strength, and may represent a risk factor for subsequent osteoporosis. © 2015 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR). PMID:26713753

  6. Calcium supplementation, bone mineral density and bone mineral content. Predictors of bone mass changes in adolescent mothers during the 6-month postpartum period.

    PubMed

    Malpeli, Agustina; Apezteguia, María; Mansur, José L; Armanini, Alicia; Macías Couret, Melisa; Villalobos, Rosa; Kuzminczuk, Marta; Gonzalez, Horacio F

    2012-03-01

    We determined the effect of calcium supplementation on bone mineral density (BMD) and bone mineral content (BMC) and identified predictors of bone mass changes in adolescent mothers 6 months postpartum. A prospective, analytical, clinical study was performed in adolescent mothers (< or = 19 years old; n = 37) from La Plata, Argentina. At 15 days postpartum, mothers were randomly assigned into one of two groups and started with calcium supplementation; one group received dairy products (932 mg Ca; n = 19) and the other calcium citrate tablets (1000 mg calcium/day; n = 18). Weight, height and dietary intake were measured and BMD was determined by DEXA at 15 days (baseline) and 6 months postpartum. BMC, total body BMD and BMD were assessed in lumbar spine, femoral neck, trochanter and total hip. Regression models were used to identify the relationship of total body BMD and BMC with independent variables (calcium supplementation, months of lactation, weight at 6 months, percent weight change, lean mass at 6 months, percent lean mass change, total calcium intake). Results showed that changes in BMD and BMC at the different sites were similar in both groups, and changes in percent body weight and total calcium intake were the main predictive factors. In conclusion, the effect of calcium was similar with either form of supplementation, i.e., dairy products or tablets, and changes in percent body weight and total calcium intake were predictors of total body BMD and BMC changes. PMID:23477205

  7. Geometric indices of hip bone strength in obese, overweight, and normal-weight adolescent girls.

    PubMed

    El Hage, Rawad; El Hage, Zaher; Moussa, Elie; Jacob, Christophe; Zunquin, Gautier; Theunynck, Denis

    2013-01-01

    The aim of this study was to compare hip bone strength indices in obese, overweight, and normal-weight adolescent girls using hip structure analysis (HSA). This study included 64 postmenarcheal adolescent girls (14 obese, 21 overweight, and 29 normal weight). The 3 groups (obese, overweight, and normal weight) were matched for maturity (years since menarche). Body composition and bone mineral density (BMD) of whole body, lumbar spine, and proximal femur were assessed by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone strength, DXA scans were analyzed at the femoral neck (FN) at its narrow neck (NN) region, the intertrochanteric (IT), and the femoral shaft (FS) by the HSA program. Cross-sectional area and section modulus were measured from hip BMD profiles. Total hip BMD and FN BMD were significantly higher in obese and overweight girls in comparison with normal-weight girls (p < 0.05). However, after adjusting for weight, using a one-way analysis of covariance, there were no significant differences among the 3 groups regarding HSA variables. This study suggests that in obese and overweight adolescent girls, axial strength and bending strength indices of the NN, IT, and FS are adapted to the increased body weight.

  8. Relationship between Weight and Bone Mineral Density in Adolescents on Hormonal Contraception

    PubMed Central

    Bonny, Andrea E.; Secic, Michelle; Cromer, Barbara A.

    2010-01-01

    Study Objective Since bone loss has been observed among adolescents on depot medroxyprogesterone acetate (DMPA), a clinical population that commonly experiences weight gain, we were interested in examining the direct relationship between body weight and bone mineral density (BMD) in adolescents on DMPA as compared to those on oral contraceptive pills (OC) or on no hormonal contraception (control). Design Prospective, Longitudinal study. Setting Four urban adolescent health clinics in a large metropolitan area. Participants Post-menarcheal girls, age 12 – 18 years, selecting DMPA, OC or no hormonal contraception. Interventions At baseline, 6, 12, 18, and 24 months, all study participants underwent measurement of weight and BMD of the hip and spine. Main Outcome Measures The correlation between weight and BMD, and the correlation between change in weight and change in BMD were assessed at each time point. Results Body weight was significantly (p < .05) positively correlated with femoral neck BMD and spine BMD at each time point regardless of contraceptive method. Change in body weight at 12 and 24 months was highly correlated with change in femoral neck BMD (p < .0001) for all treatment groups. No statistically significant correlation between change in weight and change in spine BMD was seen in the DMPA, OC or control subjects at 12 or 24 months. Conclusion Weight gain on DMPA may mitigate loss of BMD among adolescent users. PMID:20709582

  9. NACOB presentation to ASB Young Scientist Award: Postdoctoral. The impact of boundary conditions and mesh size on the accuracy of cancellous bone tissue modulus determination using large-scale finite-element modeling. North American Congress on Biomechanics.

    PubMed

    Jacobs, C R; Davis, B R; Rieger, C J; Francis, J J; Saad, M; Fyhrie, D P

    1999-11-01

    The apparent properties of cancellous bone are determined by a combination of both hard tissue properties and microstructural organization. A method is desired to extract the underlying hard tissue properties from simple mechanical tests, free from the complications of microstructure. It has been suggested that microCT voxel-based large-scale finite element models could be employed to accomplish this goal (van Rietbergen et al., 1995, Journal of Biomechanics, 28, 69-81). This approach has recently been implemented and it is becoming increasingly popular as finite element models increase in size and sophistication (Fyhrie et al., 1997, Proceedings of the 43rd Annual Meeting of the Orthopaedic Research Society, San Francisco, CA, p. 815; van Rietbergen et al., 1997, Proceedings of the 43rd Annual Meeting of the Orthopaedic Research Society, San Francisco, CA, p. 62). However, no direct quantitative measurements of the accuracy of this method applied to porous structures such as cancellous bone have been made. This project demonstrates the feasibility of this approach by quantifying its best-case accuracy in determining the trabecular hard tissue modulus of analogues fabricated of a material with known material properties determined independently by direct testing. In addition we were able to assess the impact of mesh size and boundary conditions on accuracy. We found that the assumption of a frictionless boundary condition in the parallel plate compression loading configuration was a significant source of error that could be overcome with the use of rigid end-caps similar to those used by Keaveny et al. (1997 Journal of Orthopaedic Research, 15(1), 101-110). In conclusion, we found that this approach is an effective method for determining the average trabecular hard tissue properties of human cancellous bone with an expected practical accuracy level better than 5%.

  10. Bone Mineral Density in Adolescent Females Using Injectable or Oral Contraceptives: A 24 Month Prospective Study

    PubMed Central

    Cromer, Barbara A.; Bonny, Andrea E.; Stager, Margaret; Lazebnik, Rina; Rome, Ellen; Ziegler, Julie; Camlin-Shingler, Kelly; Secic, Michelle

    2008-01-01

    Study Objective To determine whether bone mineral density (BMD) is lower in hormonal contraceptive users than that in an untreated, comparison group. Design Observational, prospective cohort; duration: 24 months. Setting Adolescent clinics in a midwestern, metropolitan setting. Patients 433 postmenarcheal girls, aged 12–18 years, on depot medroxyprogesterone acetate (DMPA) [n=58], oral contraceptives (OC) [n=187], or untreated (n=188). Intervention DMPA and OC containing 100 mcg levonorgestrel and 20 mcg ethinyl estradiol. Main Outcome Measure BMD measurements at spine and femoral neck were obtained with dual x-ray absorptiometry (DXA) at baseline and 6-month intervals. Results Over 24 months, mean percent change in spine BMD was: DMPA −1.5%, OC +4.2%, and untreated +6.3%. Mean percent change in femoral neck BMD was: DMPA −5.2%, OC +3.0%, untreated +3.8%. Statistical significance was found between the DMPA group and other two groups (p<.001). In the DMPA group, mean percent change in spine BMD over the first 12 months was −1.4%; the rate of change slowed to −0.1% over the second 12 months. No bone density loss reached the level of osteopenia. Conclusions Adolescent girls receiving DMPA had significant loss in BMD compared with bone gain in the OC and untreated group. However, its clinical significance is mitigated by slowed loss after the first year of DMPA use and general maintenance of bone density values within the normal range. PMID:18222431

  11. Association between duration of playing video games and bone mineral density in Chinese adolescents.

    PubMed

    Shao, Haiyu; Xu, Shaonan; Zhang, Jun; Zheng, Jiayin; Chen, Jinping; Huang, Yazeng; Ru, Bin; Jin, Yongming; Zhang, Qi; Ying, Qifeng

    2015-01-01

    The aim of the study was to investigate the association between duration of playing video games and bone mineral density (BMD) in Chinese adolescents. Three hundred eighty-four Chinese adolescents aged 14-18 yr (148 males and 236 females) were analyzed. Anthropometric measurements were obtained using standard procedures. Total body and regional BMD were measured using dual-energy X-ray absorptiometry. Duration of playing video games, defined as hours per day, was measured by a self-report questionnaire. We examined the association between duration of playing video games and BMD using multiple linear regression analysis. After adjustment for age, sex, pubertal stage, parental education, body mass index, adolescents with longer video game duration were more likely to have lower legs, trunk, pelvic, spine, and total BMD (p < 0.05). We concluded that duration of video game was negatively associated with BMD in Chinese adolescents. These findings provide support for reducing duration of playing video games as a possible means to increase BMD in adolescents. Future research is needed to elucidate the underlined mechanisms linking playing video games and osteoporosis.

  12. Genetic variants in adult bone mineral density and fracture risk genes are associated with the rate of bone mineral density acquisition in adolescence

    PubMed Central

    Warrington, Nicole M.; Kemp, John P.; Tilling, Kate; Tobias, Jonathan H.; Evans, David M.

    2015-01-01

    Previous studies have identified 63 single-nucleotide polymorphisms (SNPs) associated with bone mineral density (BMD) in adults. These SNPs are thought to reflect variants that influence bone maintenance and/or loss in adults. It is unclear whether they affect the rate of bone acquisition during adolescence. Bone measurements and genetic data were available on 6397 individuals from the Avon Longitudinal Study of Parents and Children at up to five follow-up clinics. Linear mixed effects models with smoothing splines were used for longitudinal modelling of BMD and its components bone mineral content (BMC) and bone area (BA), from 9 to 17 years. Genotype data from the 63 adult BMD associated SNPs were investigated individually and as a genetic risk score in the longitudinal model. Each additional BMD lowering allele of the genetic risk score was associated with lower BMD at age 13 [per allele effect size, 0.002 g/cm2 (SE = 0.0001, P = 1.24 × 10−38)] and decreased BMD acquisition from 9 to 17 years (P = 9.17 × 10−7). This association was driven by changes in BMC rather than BA. The genetic risk score explained ∼2% of the variation in BMD at 9 and 17 years, a third of that explained in adults (6%). Genetic variants that putatively affect bone maintenance and/or loss in adults appear to have a small influence on the rate of bone acquisition through adolescence. PMID:25941325

  13. Prolonged Practice of Swimming Is Negatively Related to Bone Mineral Density Gains in Adolescents

    PubMed Central

    Ribeiro-dos-Santos, Marcelo R.; Lynch, Kyle R.; Maillane-Vanegas, Santiago; Turi-Lynch, Bruna; Ito, Igor H.; Luiz-de-Marco, Rafael; Rodrigues-Junior, Mario A.; Fernandes, Rômulo A.

    2016-01-01

    Background The practice of swimming in "hypogravity" conditions has potential to decrease bone formation because it decreases the time engaged in weight-bearing activities usually observed in the daily activities of adolescents. Therefore, adolescents competing in national levels would be more exposed to these deleterious effects, because they are engaged in long routines of training during most part of the year. To analyze the effect of swimming on bone mineral density (BMD) gain among adolescents engaged in national level competitions during a 9-month period. Methods Fifty-five adolescents; the control group contained 29 adolescents and the swimming group was composed of 26 athletes. During the cohort study, BMD, body fat (BF) and fat free mass (FFM) were assessed using a dual-energy x-ray absorptiometry scanner. Body weight was measured with an electronic scale, and height was assessed using a stadiometer. Results During the follow-up, swimmers presented higher gains in FFM (Control 2.35 kg vs. Swimming 5.14 kg; large effect size [eta-squared (ES-r)=0.168]) and BMD-Spine (Swimming 0.087 g/cm2 vs. Control 0.049 g/cm2; large effect size [ES-r=0.167]) compared to control group. Male swimmers gained more FFM (Male 10.63% vs. Female 3.39%) and BMD-Spine (Male 8.47% vs. Female 4.32%) than females. Longer participation in swimming negatively affected gains in upper limbs among males (r=-0.438 [-0.693 to -0.085]), and in spine among females (r=-0.651 [-0.908 to -0.036]). Conclusions Over a 9-month follow-up, BMD and FFM gains were more evident in male swimmers, while longer engagement in swimming negatively affected BMD gains, independently of sex.

  14. Prolonged Practice of Swimming Is Negatively Related to Bone Mineral Density Gains in Adolescents

    PubMed Central

    Ribeiro-dos-Santos, Marcelo R.; Lynch, Kyle R.; Maillane-Vanegas, Santiago; Turi-Lynch, Bruna; Ito, Igor H.; Luiz-de-Marco, Rafael; Rodrigues-Junior, Mario A.; Fernandes, Rômulo A.

    2016-01-01

    Background The practice of swimming in "hypogravity" conditions has potential to decrease bone formation because it decreases the time engaged in weight-bearing activities usually observed in the daily activities of adolescents. Therefore, adolescents competing in national levels would be more exposed to these deleterious effects, because they are engaged in long routines of training during most part of the year. To analyze the effect of swimming on bone mineral density (BMD) gain among adolescents engaged in national level competitions during a 9-month period. Methods Fifty-five adolescents; the control group contained 29 adolescents and the swimming group was composed of 26 athletes. During the cohort study, BMD, body fat (BF) and fat free mass (FFM) were assessed using a dual-energy x-ray absorptiometry scanner. Body weight was measured with an electronic scale, and height was assessed using a stadiometer. Results During the follow-up, swimmers presented higher gains in FFM (Control 2.35 kg vs. Swimming 5.14 kg; large effect size [eta-squared (ES-r)=0.168]) and BMD-Spine (Swimming 0.087 g/cm2 vs. Control 0.049 g/cm2; large effect size [ES-r=0.167]) compared to control group. Male swimmers gained more FFM (Male 10.63% vs. Female 3.39%) and BMD-Spine (Male 8.47% vs. Female 4.32%) than females. Longer participation in swimming negatively affected gains in upper limbs among males (r=-0.438 [-0.693 to -0.085]), and in spine among females (r=-0.651 [-0.908 to -0.036]). Conclusions Over a 9-month follow-up, BMD and FFM gains were more evident in male swimmers, while longer engagement in swimming negatively affected BMD gains, independently of sex. PMID:27622179

  15. Obesity Impact Evaluated from Fat Percentage in Bone Mineral Density of Male Adolescents

    PubMed Central

    Ripka, Wagner Luis; Modesto, Jhomyr Dias; Ulbricht, Leandra; Gewehr, Pedro Miguel

    2016-01-01

    Objective To analyze bone mineral density (BMD) values in adolescents and to assess obesity impact, measured through body fat #x2013;on this variable through the assessment by DEXA. Methodology A total of 318 males adolescents (12–17 years) were evaluated considering weight, height, body mass index (BMI), bone mineral density (BMD), fat and lean mass. BMD was assessed for the arms, legs, hips, and lumbar regions, as well as for total amount. Stratification of the nutritional status was determined by body fat (%BF) percentage; comparison of groups was scrutinized by analysis of variance; and the association of variables was performed using Pearson's test. Results There was a progressive increase in weight, height, and BMD for all evaluated age groups following the advance of chronological age. A negative correlation was found between the %BF with BMD in all evaluated segments. Significant differences were found between the eutrophic group compared to the overweight group and the obesity group in the evaluated segments (P <0.01) noting a reduction of up to 12.92% for the lumbar region between eutrophic and obese. Conclusion The results suggest that increase %BF is associated with lower BMD among male adolescents. PMID:27685942

  16. Effects of Phlomis umbrosa Root on Longitudinal Bone Growth Rate in Adolescent Female Rats.

    PubMed

    Lee, Donghun; Kim, Young-Sik; Song, Jungbin; Kim, Hyun Soo; Lee, Hyun Jung; Guo, Hailing; Kim, Hocheol

    2016-01-01

    This study aimed to investigate the effects of Phlomis umbrosa root on bone growth and growth mediators in rats. Female adolescent rats were administered P. umbrosa extract, recombinant human growth hormone or vehicle for 10 days. Tetracycline was injected intraperitoneally to produce a glowing fluorescence band on the newly formed bone on day 8, and 5-bromo-2'-deoxyuridine was injected to label proliferating chondrocytes on days 8-10. To assess possible endocrine or autocrine/paracrine mechanisms, we evaluated insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3) or bone morphogenetic protein-2 (BMP-2) in response to P. umbrosa administration in either growth plate or serum. Oral administration of P. umbrosa significantly increased longitudinal bone growth rate, height of hypertrophic zone and chondrocyte proliferation of the proximal tibial growth plate. P. umbrosa also increased serum IGFBP-3 levels and upregulated the expressions of IGF-1 and BMP-2 in growth plate. In conclusion, P. umbrosa increases longitudinal bone growth rate by stimulating proliferation and hypertrophy of chondrocyte with the increment of circulating IGFBP-3. Regarding the immunohistochemical study, the effect of P. umbrosa may also be attributable to upregulation of local IGF-1 and BMP-2 expressions in the growth plate, which can be considered as a GH dependent autocrine/paracrine pathway. PMID:27070559

  17. Body Composition During Childhood and Adolescence: Relations to Bone Strength and Microstructure

    PubMed Central

    Amin, Shreyasee; LeBrasseur, Nathan K.; Atkinson, Elizabeth J.; Achenbach, Sara J.; McCready, Louise K.; Joseph Melton, L.; Khosla, Sundeep

    2014-01-01

    Context: Numerous studies have examined the association of body composition with bone development in children and adolescents, but none have used micro-finite element (μFE) analysis of high-resolution peripheral quantitative computed tomography images to assess bone strength. Objective: This study sought to examine the relations of appendicular lean mass (ALM) and total body fat mass (TBFM) to bone strength (failure load) at the distal radius and tibia. Design, Participants, and Setting: This was a cross-sectional study of 198 healthy 8- to <15-year-old boys (n = 109) and girls (n = 89) performed in a Clinical Research Unit. Results: After adjusting for bone age, height, fracture history, ALM, and TBFM, multiple linear regression analyses in boys and girls, separately, showed robust positive associations between ALM and failure loads at both the distal radius (boys: β = 0.92, P < .001; girls: β = 0.66, P = .001) and tibia (boys: β = 0.96, P < .001; girls: β = 0.66, P < .001). By contrast, in both boys and girls the relationship between TBFM and failure load at the distal radius was virtually nonexistent (boys: β = −0.07; P = .284; girls: β = −0.03; P = .729). At the distal tibia, positive, albeit weak, associations were observed between TBFM and failure load in both boys (β = 0.09, P = .075) and girls (β = 0.17, P = .033). Conclusions: Our data highlight the importance of lean mass for optimizing bone strength during growth, and suggest that fat mass may have differential relations to bone strength at weight-bearing vs non-weight-bearing sites in children and adolescents. These observations suggest that the strength of the distal radius does not commensurately increase with excess gains in adiposity during growth, which may result in a mismatch between bone strength and the load experienced by the distal forearm during a fall. These findings may explain, in part, why obese children are over-represented among distal forearm fracture cases. PMID:25243571

  18. Atypical Clival Chordoma in an Adolescent without Imaging Evidence of Bone Involvement

    PubMed Central

    HASHIM, Hilwati; ROSMAN, Azmin Kass; ABDUL AZIZ, Aida; ROQIAH, Abdul Kadir; BAKAR, Nor Salmah

    2014-01-01

    Clival chordoma is a rare primary bone tumour that arises from the remnant of the notochord and typically occurs in older adults. Upon imaging, the tumour can be seen arising from the clivus and causes clival destruction. This usually provides insight for a diagnosis. Here we present a case of a non-enhancing, pre-pontine mass that was hypointense on T1W and hyperintense on T2W in an adolescent. No clival bone erosion was observed. Based on the age group, imaging findings, and lack of clival erosion, a provisional diagnosis of epidermoid cyst was made and the tumour was resected. This patient was eventually diagnosed with a clival chordoma based on histopathological examination. PMID:25977639

  19. Growth promoting in vitro effect of synthetic cyclic RGD-peptides on human osteoblast-like cells attached to cancellous bone.

    PubMed

    Magdolen, Ursula; Auernheimer, Jörg; Dahmen, Claudia; Schauwecker, Johannes; Gollwitzer, Hans; Tübel, Jutta; Gradinger, Reiner; Kessler, Horst; Schmitt, Manfred; Diehl, Peter

    2006-06-01

    In tissue engineering, the application of biofunctional compounds on biomaterials such as integrin binding RGD-peptides has gained growing interest. Anchorage-dependent cells like osteoblasts bind to these peptides thus ameliorating the integration of a synthetic implant. In case sterilized bone grafts are used as substitutes for reconstruction of bone defects, the ingrowth of the implanted bone is often disturbed because of severe pretreatment such as irradiation or autoclaving, impairing the biological and mechanical properties of the bone. We report for the first time on the in vitro coating of the surface of freshly resected, cleaned bone discs with synthetic, cyclic RGD-peptides. For this approach, two different RGD-peptides were used, one containing two phosphonate anchors, the other peptide four of these binding moieties to allow efficient association of these reactive RGD-peptides to the inorganic bone matrix. Human osteoblast-like cells were cultured on RGD-coated bone discs and the adherence and growth of the cells were analyzed. Coating of bone discs with RGD-peptides did not improve the adhesion rate of osteoblast-like cells to the discs but significantly (up to 40%) accelerated growth of these cells within 8 days after attachment. This effect points to pretreatment of bone implants, especially at the critical interface area between the implanted bone and the non-resected residual bone structure, before re-implantation in order to stimulate and enhance osteointegration of a bone implant. PMID:16685410

  20. Percent fat mass is inversely associated with bone mass and hip geometry in rural Chinese adolescents.

    PubMed

    Hong, Xiumei; Arguelles, Lester M; Liu, Xin; Tsai, Hui-Ju; Hsu, Yi-Hsiang; Wang, Binyan; Zhang, Shanchun; Li, Zhiping; Tang, Gengfu; Liu, Xue; Yang, Jianhua; Xu, Xiping; Langman, Craig; Wang, Xiaobin

    2010-07-01

    This study was an attempt to examine the phenotypic, genetic, and environmental correlations between percent fat mass (PFM) and bone parameters, especially hip geometry, among 786 males and 618 females aged 13 to 21 years from a Chinese twin cohort. PFM, bone area (BA), bone mineral content (BMC), cross-sectional area (CSA), and section modulus (SM) were obtained by dual-energy X-ray absorptiometry. Multiple linear regression models were used to assess the PFM-bone relationships. A structural equation model for twin design was used to estimate genetic/environmental influences on individual phenotype and phenotypic correlations. After controlling for body weight and other pertinent covariates, we observed inverse associations between PFM and bone parameters: Compared with the lowest age- and gender-specific tertile of PFM, males in the highest tertile of PFM had lower measures of whole-body-less-head BA (WB-BA), lumbar spine BA (L(2)-L(4)-BA), total-hip BA (TH-BA), total-hip BMC, CSA, and SM (p < .005 for all, adjusted p < .05). Similar inverse associations were observed in females for all the preceding parameters except WB-BA and L2-L(4)-BA. These associations did not vary significantly by Tanner stages. In both genders, the estimated heritabilities were 80% to 86% for BMC, 67% to 80% for BA, 74% to 77% for CSA, and 64% for SM. Both shared genetics and environmental factors contributed to the inverse PFM-bone correlations. We conclude that in this sample of relatively lean Chinese adolescents, at a given body weight, PFM is inversely associated with BA, BMC, and hip geometry in both genders, and such associations are attributed to both shared genetic and environmental factors.

  1. Endocrine disruption in adolescence: immunologic, hematologic, and bone effects in monkeys.

    PubMed

    Golub, Mari S; Hogrefe, Casey E; Germann, Stacey L; Jerome, Christopher P

    2004-12-01

    Environmental contaminants with estrogenic properties have the potential to alter pubertal development. In addition to the reproductive system, other systems that mature under the influence of estrogen could be affected. This study examined the effect on immune, hematologic, and bone mass parameters of treatment with estrogenic agents (methoxychlor, MXC, 25 and 50 mg/kg/day; diethylstilbestrol, DES, 0.5 mg/kg/day) given in the peripubertal period to female rhesus monkeys. DES had striking effects on several parameters assessed measures CBC and clinical chemistry including hematocrit, hemoglobin, serum albumin, liver transaminases, and lipids. Circulating lymphocytes, particularly B cells, were depressed by DES, and a maturational shift in a memory T-cell population was altered. Bone mass and length, as measured after a 9-month recovery period, were significantly lower in the DES group and bone mass tended to be reduced in the femur of the MXC50 group relative to controls. In conclusion, the data indicate that DES had a clear effect on immunohematology and bone growth, while MXC influenced fewer parameters. Disruption in these systems during puberty could alter adolescent risk for anemia and infectious disease and subsequent adult risk for diseases such as osteoporosis, heart disease, and autoimmune disease.

  2. Histomorphometric and 3D Cone-Beam Computerized Tomographic Evaluation of Socket Preservation in Molar Extraction Sites Using Human Particulate Mineralized Cancellous Allograft Bone With a Porcine Collagen Xenograft Barrier: A Case Series.

    PubMed

    Wallace, Stephen

    2015-06-01

    The purpose of this study was to evaluate the results of socket preservation after extraction using human particulate mineralized cancellous allograft bone (MCAB) and type I porcine collagen membranes (PCM) as a guided bone regeneration barrier. Fourteen patients, 12 women and 2 men, were selected who had a diagnosis of one or more unsalvageable teeth with a treatment plan to replace them with implant-supported single crown restorations. Extractions were preformed atraumatically by sectioning teeth for removal to avoid damaging the socket walls and by immediately placing MCAB graft to fill the sockets. The sockets were occluded with a new PCM. The membranes were cut to overlap the facial and lingual (or palatal) socket rim by at least 5 mm (or more if necessary) to cover bony wall fenestration or dehiscence defects. Implants were then placed 16 weeks after the extractions and augmentation. The results were evaluated clinically, histomorphometrically, and with cone-beam computerized tomographic scanning. The formation of new bone in the treated sites averaged 11.2%, with a range of 1.8% to 43%, in bone biopsies trephined from the center of the grafted socket sites. Density, calculated with proprietary software and measured in Hounsfield units (HUs), was 543 HU with a range of 420 to 822 HU. The resulting new bone regeneration varied widely, but the barrier membranes showed potential for promoting significant bone regeneration. A larger sample of treated cases is needed. Wall defects did not appear to influence the histologic results, but the number of sites was too small to determine their significance.

  3. Bone speed of sound and physical activity levels of overweight and normal-weight girls and adolescents.

    PubMed

    Yao, Mathew; Ludwa, Izabella; Corbett, Lauren; Klentrou, Panagiota; Bonsu, Peter; Gammage, Kimberley; Falk, Bareket

    2011-02-01

    Bone properties, reflected by speed of sound (SOS), and physical activity levels were examined in overweight (OW) girls (n = 19) and adolescents (n = 22), in comparison with normal-weight (NW) girls (n = 21) and adolescents (n = 13). Moderate-to-vigorous physical activity (MVPA) was higher in NW than in OW in both age groups. Tibial SOS was lower in OW compared with NW in both age groups. MVPA correlated with tibial SOS, once age was partialed out. The results suggest that overweight girls and adolescents are characterized by low tibial SOS, which may be partially attributed to lower physical activity levels.

  4. Comparison of the Effect of Velvet Antler from Different Sections on Longitudinal Bone Growth of Adolescent Rats

    PubMed Central

    Kim, Hye Kyung; Kim, Myung-Gyou

    2016-01-01

    The aim of this study was to compare the effectiveness of velvet antler (VA) from different sections for promoting longitudinal bone growth in growing rats. VA was divided into upper (VAU), middle (VAM), and basal sections (VAB). An in vivo study was performed to examine the effect on longitudinal bone growth in adolescent rats. In addition, in vitro osteogenic activities were examined using osteoblastic MG-63 cells. VA promoted longitudinal bone growth and height of the growth plate in adolescent rats. Bone morphogenetic protein-2 (BMP-2) in growth plate of VA group was highly expressed compared with control. The anabolic effect of VA on bone was further supported by in vitro study. VA enhanced the proliferation, differentiation, and mineralization of MG-63 cells. The mRNA expressions of osteogenic genes such as collagen, alkaline phosphatase, and osteocalcin were increased by VA treatment. These effects of in vivo and in vitro study were decreased from upper to basal sections of VA. In conclusion, VA treatment promotes longitudinal bone growth in growing rats through enhanced BMP-2 expression, osteogenic activities, and bone matrix gene expressions. In addition, present study provides evidence for the regional differences in the effectiveness of velvet antler for longitudinal bone growth. PMID:27382403

  5. Adolescents with childhood-onset GHD: how do we get them to peak bone mass?

    PubMed

    Shalet, Stephen

    2006-01-01

    The development of osteoporosis, with its attendant risk of fragility fracture, is in part related to the peak bone mass (PBM) achieved in early adulthood. Adolescence is a critical time for the acquisition of bone mass, with around 40% of skeletal mass being accrued during pubertal maturation. Growth hormone (GH) plays an integral role in the achievement of PBM after completion of linear growth, and several recent studies have suggested that GH replacement should continue in individuals with childhood-onset GHD until PBM has been attained - irrespective of the height achieved. In those with severe GHD after growth and pubertal development are complete, a seamless transition of GH therapy into adult life may be preferable to allowing a gap in GH treatment. The 'window of opportunity' concept for achieving PBM will, nevertheless, continue to be challenged by GHD teenagers who may resent the seamless continuation of GH replacement beyond adolescence. Preparation for this possibility should therefore begin during childhood, with all GHD teenagers being encouraged to remain on GH therapy until at least their mid-20s.

  6. Grip strength is a predictor of bone mineral density among adolescent combat sport athletes.

    PubMed

    Nasri, Raouf; Hassen Zrour, Saoussen; Rebai, Haithem; Fadhel Najjar, Mohamed; Neffeti, Fadoua; Bergaoui, Naceur; Mejdoub, Hafedh; Tabka, Zouhair

    2013-01-01

    The aim of this study was firstly to investigate the correlation between bone parameters and grip strength (GS) in hands, explosive legs power (ELP), and hormonal parameters; second, to identify the most determinant variables of bone mineral density (BMD) among adolescent combat sport athletes. Fifty combat sport athletes aged 17.1 ± 0.2 year were compared with 30 sedentary subjects matched for age, height, and pubertal stage. For all subjects, the BMD in deferent sites associated with anthropometric parameters were measured by dual-energy X-ray absorptiometry. The growth hormone (GH) and testosterone (TESTO) concentrations were tested. The GS in dominant (GSDA) and nondominant arms (GSNDA) and ELP were evaluated. All BMD measured were greater in athletes than in sedentary group (p<0.01). The GS and ELP showed higher values in athletes than in sedentary group (p<0.01). The BMD in all sites were correlated with weight, but without correlation with height. The GSNDA and ELP were significantly correlated with BMD of both spine and legs. The GH was correlated with the BMD of whole body and spine (p<0.05). The TESTO was only correlated with BMD of the arms (p<0.01). The best predictor of BMD measurements is GSNDA. This study has proved the osteogenic effect of combat sports practice, especially judo and karate kyokushinkai. Therefore, children and adolescent should be encouraged to participate in combat sport. Moreover, it suggested that the best model predicting BMD in different sites among adolescent combat sports athletes was the GSNDA. PMID:22980488

  7. Grip strength is a predictor of bone mineral density among adolescent combat sport athletes.

    PubMed

    Nasri, Raouf; Hassen Zrour, Saoussen; Rebai, Haithem; Fadhel Najjar, Mohamed; Neffeti, Fadoua; Bergaoui, Naceur; Mejdoub, Hafedh; Tabka, Zouhair

    2013-01-01

    The aim of this study was firstly to investigate the correlation between bone parameters and grip strength (GS) in hands, explosive legs power (ELP), and hormonal parameters; second, to identify the most determinant variables of bone mineral density (BMD) among adolescent combat sport athletes. Fifty combat sport athletes aged 17.1 ± 0.2 year were compared with 30 sedentary subjects matched for age, height, and pubertal stage. For all subjects, the BMD in deferent sites associated with anthropometric parameters were measured by dual-energy X-ray absorptiometry. The growth hormone (GH) and testosterone (TESTO) concentrations were tested. The GS in dominant (GSDA) and nondominant arms (GSNDA) and ELP were evaluated. All BMD measured were greater in athletes than in sedentary group (p<0.01). The GS and ELP showed higher values in athletes than in sedentary group (p<0.01). The BMD in all sites were correlated with weight, but without correlation with height. The GSNDA and ELP were significantly correlated with BMD of both spine and legs. The GH was correlated with the BMD of whole body and spine (p<0.05). The TESTO was only correlated with BMD of the arms (p<0.01). The best predictor of BMD measurements is GSNDA. This study has proved the osteogenic effect of combat sports practice, especially judo and karate kyokushinkai. Therefore, children and adolescent should be encouraged to participate in combat sport. Moreover, it suggested that the best model predicting BMD in different sites among adolescent combat sports athletes was the GSNDA.

  8. Evaluation of bone density in infancy and adolescence. Review of medical literature and personal experience

    PubMed Central

    Pedrotti, Luisella; Bertani, Barbara; Tuvo, Gabriella; Barone, Francesca; Crivellari, Ilaria; Lucanto, Stefano; Redento, Mora

    2010-01-01

    The evolution of medical and surgical therapies allows the increased survival rate of a growing number of children affected by rare pathologies. In this light osteoporotic disease is also of orthopaedic interest as it is sometimes the outward manifestation of serious pathologies (i.e. osteogenesis imperfecta). Sometimes, even in infancy and adolescence, osteoporosis is associated with complications due to fractures; in other cases it seems to have no immediate consequence. Nevertheless it must be considered as a fracture risk factor in adulthood as it negatively affects the achievement of peak bone mass. The evaluation of variations in bone mass that take place during growth is thus of particular importance in order to guarantee a level of bone health suitable for the next phase. These remarks compose the premise of a study on bone resistance carried out on a study population of between 6 and 18 years of age in the city of Pavia. To determine the resistance of the bone an ultrasound device was employed (Omnisense™ , Sunlight Medical Ltd, Tel Aviv, Israel) in two skeletal sites, distal radius and midshaft of tibia. The analysis of our results and a review of the relevant literature indicate that the median values of normality, against which we compare the measurements of the patients under examination, depend not only on age, sex, skeletal sites, race, and even ethnic group. The introduction of this new parameter, to be kept in mind when interpreting the results, invites us to be very prudent in determining the diagnostic threshold values in paediatric age. As with anthropometric data (weight, height, cranial circumference) it is possible to suggest an interpretation of the patient’s SOS values comparing them with the ‘centile curves’ typical to the region the child belongs to. Of course, further studies are required to understand what are the variables involved and to determine the extension of the geographical area to be examined to obtain suitable

  9. Does hormone replacement normalize bone geometry in adolescents with anorexia nervosa?

    PubMed

    DiVasta, Amy D; Feldman, Henry A; Beck, Thomas J; LeBoff, Meryl S; Gordon, Catherine M

    2014-01-01

    Young women with anorexia nervosa (AN) have reduced secretion of dehydroepiandrosterone (DHEA) and estrogen contributing to skeletal deficits. In this randomized, placebo-controlled trial, we investigated the effects of oral DHEA + combined oral contraceptive (COC) versus placebo on changes in bone geometry in young women with AN. Eighty women with AN, aged 13 to 27 years, received a random, double-blinded assignment to micronized DHEA (50 mg/day) + COC (20 µg ethinyl estradiol/0.1 mg levonorgestrel) or placebo for 18 months. Measurements of areal bone mineral density (aBMD) at the total hip were obtained by dual-energy X-ray absorptiometry at 0, 6, 12, and 18 months. We used the Hip Structural Analysis (HSA) program to determine BMD, cross-sectional area (CSA), and section modulus at the femoral neck and shaft. Each measurement was expressed as a percentage of the age-, height-, and lean mass-specific mean from an independent sample of healthy adolescent females. Over the 18 months, DHEA + COC led to stabilization in femoral shaft BMD (0.0 ± 0.5% of normal mean for age, height, and lean mass/year) compared with decreases in the placebo group (-1.1 ± 0.5% per year, p = 0.03). Similarly, CSA, section modulus, and cortical thickness improved with treatment. In young women with AN, adrenal and gonadal hormone replacement improved bone health and increased cross-sectional geometry. Our results indicate that this combination treatment has a beneficial impact on surrogate measures of bone strength, and not only bone density, in young women with AN.

  10. Bone mineral density in a cohort of adolescent women using depot medroxyprogesterone acetate for one to two years.

    PubMed

    Busen, Nancy H; Britt, Robin B; Rianon, Nahid

    2003-04-01

    The purpose of this study was to examine estradiol and bone mineral density (BMD) in a cohort of adolescents using depot medroxyprogesterone acetate (DMPA) for one to two years. BMD was significantly decreased in the femoral neck and lumbar spine at year one. Estradiol levels suggested hypoestrogenization among subjects

  11. Adolescent and School Health

    MedlinePlus

    ... Search The CDC Cancel Submit Search The CDC Adolescent and School Health Note: Javascript is disabled or ... behaviors now JAMA Viewpoint: Lesbian, Gay, and Bisexual Adolescents New MMWR Article Learn What State and Local ...

  12. Influence of physical activity on bone strength in children and adolescents: a systematic review and narrative synthesis.

    PubMed

    Tan, Vina P S; Macdonald, Heather M; Kim, SoJung; Nettlefold, Lindsay; Gabel, Leigh; Ashe, Maureen C; McKay, Heather A

    2014-10-01

    A preponderance of evidence from systematic reviews supports the effectiveness of weight-bearing exercises on bone mass accrual, especially during the growing years. However, only one systematic review (limited to randomized controlled trials) examined the role of physical activity (PA) on bone strength. Thus, our systematic review extended the scope of the previous review by including all PA intervention and observational studies, including organized sports participation studies, with child or adolescent bone strength as the main outcome. We also sought to discern the skeletal elements (eg, mass, structure, density) that accompanied significant bone strength changes. Our electronic-database, forward, and reference searches yielded 14 intervention and 23 observational studies that met our inclusion criteria. We used the Effective Public Health Practice Project (EPHPP) tool to assess the quality of studies. Due to heterogeneity across studies, we adopted a narrative synthesis for our analysis and found that bone strength adaptations to PA were related to maturity level, sex, and study quality. Three (of five) weight-bearing PA intervention studies with a strong rating reported significantly greater gains in bone strength for the intervention group (3% to 4%) compared with only three significant (of nine) moderate intervention studies. Changes in bone structure (eg, bone cross-sectional area, cortical thickness, alone or in combination) rather than bone mass most often accompanied significant bone strength outcomes. Prepuberty and peripuberty may be the most opportune time for boys and girls to enhance bone strength through PA, although this finding is tempered by the few available studies in more mature groups. Despite the central role that muscle plays in bones' response to loading, few studies discerned the specific contribution of muscle function (or surrogates) to bone strength. Although not the focus of the current review, this seems an important consideration

  13. Cancellous osteoma of maxilla: A rare case report

    PubMed Central

    Debta, Priyanka; Debta, F. M.; Bussari, Smita; Acharya, Swati S.; Jeergal, Vasanti A.

    2016-01-01

    Osteoma is a slow growing benign tumor result from either cancellous or compact bone proliferation. Osteoma of the jaws may arise from the surface of the bone as a sessile mass located either peripherally or endosteally. This paper presents a rare case report of peripheral cancellous osteoma, involving the buccal cortical plate and alveolar process of the right maxilla of a 37-year-old female patient. PMID:27382545

  14. Cancellous osteoma of maxilla: A rare case report.

    PubMed

    Debta, Priyanka; Debta, F M; Bussari, Smita; Acharya, Swati S; Jeergal, Vasanti A

    2016-01-01

    Osteoma is a slow growing benign tumor result from either cancellous or compact bone proliferation. Osteoma of the jaws may arise from the surface of the bone as a sessile mass located either peripherally or endosteally. This paper presents a rare case report of peripheral cancellous osteoma, involving the buccal cortical plate and alveolar process of the right maxilla of a 37-year-old female patient. PMID:27382545

  15. Are Volumetric Bone Mineral Density and Bone Micro-Architecture Associated with Leptin and Soluble Leptin Receptor Levels in Adolescent Idiopathic Scoliosis? – A Case-Control Study

    PubMed Central

    Tam, Elisa M. S.; Yu, Fiona W. P.; Hung, Vivian W. Y.; Liu, Zhen; Liu, King Lok; Ng, Bobby K. W.; Lee, Simon K. M.; Qiu, Yong; Cheng, Jack C. Y.; Lam, Tsz-Ping

    2014-01-01

    Background Adolescent idiopathic scoliosis (AIS) is associated with low bone mineral density (BMD). The underlying etiology and how it may relate to the development of osteopenia remains unknown. Leptin has been postulated as one of the etiologic factors of AIS because of its profound effects on bone metabolism and pubertal growth. Its modulator, soluble leptin receptor (sOB-R), may affect leptin bioavailability and signaling. This study aimed to investigate whether serum leptin and sOB-R levels may be associated with bone quality, and whether these relationships may differ between young adolescent girls with and without AIS. Methods This was a case-control study involving 94 newly diagnosed AIS girls (Cobb angle 12–48°) aged 12 to 14 years old and 87 age and gender-matched normal controls. Subjects with BMI>23.0 Kg/m2 were excluded. Anthropometric measurements including body weight, height, arm span and sitting height were taken. Serum total leptin and sOB-R were assayed with ELISA. Non-dominant distal radius was scanned with High Resolution pQCT for assessing bone quality in terms of bone morphometry, volumetric BMD (vBMD) and trabecular bone micro-architecture. Results Compared with normal controls, AIS girls had numerically higher sOB-R (p = 0.006), lower average vBMD (p = 0.048), lower cortical vBMD (p = 0.029), higher cortical bone perimeter (p = 0.014) and higher trabecular area (p = 0.027), but none remained statistically significant after the Hochberg-Benjamini procedure. Correlation analysis on serum leptin level indicated that distinctive correlations with trabecular bone parameters occurred only in AIS. Conclusion This study showed that bone quality in AIS girls was deranged as compared with controls. In addition, the distinct differences in correlation pattern between leptin and trabecular bone parameters indicated possible abnormalities in bone metabolism and dysfunction of the leptin signaling pathway in AIS. PMID:24516571

  16. Long-term voluntary exercise of male mice induces more beneficial effects on cancellous and cortical bone than on the collagenous matrix.

    PubMed

    Isaksson, Hanna; Tolvanen, Viivi; Finnilä, Mikko A J; Iivarinen, Jarkko; Turunen, Antti; Silvast, Tuomo S; Tuukkanen, Juha; Seppänen, Kari; Arokoski, Jari P A; Brama, Pieter A; Jurvelin, Jukka S; Helminen, Heikki J

    2009-11-01

    The effects of lifelong physical exercise on the composition, structure and mechanical properties of bone are not well understood. Earlier, we found that voluntary physical exercise improved various properties of bone in maturing male mice up to 6 months of age. In this study, we extended the previous study to 18 months. Half of the mice (total N=144) had access to running wheels while half were kept sedentary. The collagen network was assessed biochemically and by tensile testing of decalcified bone. The mineralized femur was analyzed with pQCT and three-point-bending of the diaphysis and neck-strength-test. The proximal tibia was analyzed with microCT. The bone collagen revealed inferior tensional properties with aging and the mineralized femur demonstrated decreased stiffness with age. In the running mice, tensile properties and the BMD were reduced at 18 months of age compared to the sedentary mice. In contrast, the stiffness of both the diaphysis and femoral neck was higher, and trabecular architecture and structure were improved in the running mice. In summary, the results suggest that lifelong exercise training of male mice results in more beneficial effects on intact mineralized bone in both the diaphysis and epiphysis than on bone collagenous matrix.

  17. Active lifestyle in childhood and adolescence prevents obesity development in young adulthood: Iowa Bone Development Study

    PubMed Central

    Kwon, Soyang; Janz, Kathleen F.; Letuchy, Elena M.; Burns, Trudy L.; Levy, Steven M.

    2015-01-01

    Objective To test the hypothesis that individuals who are active but who decrease physical activity (PA) over time have a higher risk of becoming obese in young adulthood, when compared to individuals who are consistently active throughout childhood and adolescence. Methods Iowa Bone Development Study cohort members (242 males and 251 females) participated in accelerometry assessments, dual-energy X-ray absorptiometry scans, and dietary questionnaire surveys at ages 5, 8, 11, 13, 15, 17, and 19 years. Group-based trajectory analyses identified distinct trajectory patterns of moderate- to vigorous-intensity PA (MVPA), percentage of body fat (%BF), and energy intake. A multivariable logistic regression model was fit to estimate the odds of “becoming obese” based on the MVPA trajectories, adjusted for mother’s education, somatic maturation, and energy intake. Results Among males, 74.7% had a “normal” body fat pattern, 14.6% had a “becoming obese” pattern, and 10.7% had a “consistently obese” pattern, while among females, the percentages were 58.6%, 28.6% and 12.8%, respectively. Participants who were active (≥45 minutes MVPA) as children but decreased MVPA with age were more likely to become obese, compared to consistently active participants (adjusted OR=2.77; 95% CI=1.16, 6.58). Conclusions An active lifestyle throughout childhood and adolescence could prevent obesity development in young adulthood. PMID:26538514

  18. Anorexia nervosa in female adolescents: endocrine and bone mineral density disturbances.

    PubMed

    Muñoz, M T; Argente, J

    2002-09-01

    Anorexia nervosa (AN) is a chronic childhood psychiatric illness that involves a reduction in caloric intake, loss of weight and amenorrhea, either primary or secondary. The diagnostic criteria for AN have been established by the American Psychiatric Association. The prevalence of this disease amongst adolescents and young adults is between 0.5 and 1% and the incidence of new cases per year is approximately 5-10/100,000 between 15 and 19 years of age.A number of endocrine and metabolic disturbances have been described in patients with AN including amenorrhea-oligomenorrhea, delayed puberty, hypothyroidism, hypercortisolism, IGF-I deficiency, electrolyte abnormalities, hypoglycemia and hypophosphatemia, among others. In addition to prolonged amenorrhea, osteopenia and osteoporosis are the most frequent complications leading to clinically relevant fractures and increased fracture risk throughout life. Patients exhibit an alteration in the hypothalamic-pituitary-gonadal axis, which is responsible for the menstrual disorders. The increase in gonadotropin secretion that can be observed after ponderal recuperation suggests that malnutrition could be the most important mechanism involved in the decrease in gonadotropin secretion. The loss of fat tissue as a consequence of nutrient restriction has been associated with hypoleptinemia and abnormal secretion of peptides implicated in food control (neuropeptide Y, melanocortins and corticotropin-releasing factor, among others).A review of the endocrine abnormalities, disturbances in neurotransmitters, as well as a detailed analysis of bone markers and bone mineral density in patients with AN is described.

  19. Comparison of bone mineral density between athletic and non-athletic Chinese male adolescents.

    PubMed

    Tsai, S C; Kao, C H; Wang, S J

    1996-10-01

    For the evaluation of the effect of exercise on bone mineral density of adolescent athletes, twenty-nine Chinese male adolescent athletes, each of whom had regular training in his major sport which included baseball, swimming, judo and middle/long-distance running for one to six years and eight age-matched non-athletic controls were included in this study. Bone mineral density (BMD) was measured in all study subjects using dual photo absorptiometry at the second to fourth lumbar spines (L2-4) and the right femoral neck (FN). The results revealed the following: (1) the combined group of athletes had significantly greater BMD of L2-4 (1.08 +/- 0.09 g/cm2) than the control group (0.99 +/- 0.08 g/cm2) and a tendency for greater BMD of FN (1.15 +/- 0.13 g/cm2) than the control group (1.09 +/- 0.13 g/cm2); (2) judo majors had significantly greater BMD of L2-4 than baseball majors (P < 0.05), swimming majors (P < 0.01), track majors (P < 0.05) and controls (P < 0.005); (3) baseball majors had significantly greater BMD of L2-4 than controls (P < 0.05) and greater BMD of FN than swimming majors (P < 0.05), judo majors (P < 0.05), track majors (P < 0.005) and controls (P < 0.005); (4) body weight and body mass index (BMI) had good correlation with BMD of L2-4 and FN in control group, (5) in the combined group of athletes, weight and BMI were only strongly linked to BMD of FN, and not to BMD of L2-4. There was no good correlation between BMI and BMD of L2-4 and FN in any group of athletes. We concluded that (1) physical activity during adolescence may contribute significantly towards increasing BMD of athletes and (2) the training type may provide a specific stimulus for increasing BMD at specific localized sites experienced in training.

  20. Navel jewelry artifacts and intravertebral variation in spine bone densitometry in adolescents and young women.

    PubMed

    Ott, Susan M; Ichikawa, Laura E; LaCroix, Andrea Z; Scholes, Delia

    2009-01-01

    Non-removable navel jewelry can increase the measured bone density of the underlying vertebra. We measured lumbar spine bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) in an observational study of 727 adolescents and young women aged 14-30 yr. We evaluated several methods of correcting BMD: manually erasing a small area, eliminating 1 or 2 vertebrae, estimating the BMD from 1 or 2 vertebrae using data from remaining vertebrae, and estimating the BMD using T-scores of the remaining vertebrae. Ten percent (n=71) of the subjects were wearing navel jewelry. The areal BMD by DXA of L1 and L2 was similar in those with jewels as in controls without jewels, but L3-L4 showed higher bone density in those with jewelry, and the spine BMD of L1-L4 was significantly higher in the bejeweled women (1.043+/-0.011 vs 1.006+/-0.004 g/cm2, p=0.01). The estimated errors in accuracy (g/cm2) were 0.034 due to the jewels; 0.005 from erasing a small area; 0.019 from eliminating L4; 0.044 from eliminating both L3 and L4; 0.016 from predicting BMD using L1-L3; and 0.028 using L1-L2. The T-scores using the Hologic database were progressively lower in the caudal vertebrae, even in 96 local women aged 30-35 yr, whose average T-score was 0.35 at L1 but -0.26 at L4. Thus, we found significant errors due to intravertebral variability. We suggest the optimal method of correcting for small artifacts is to erase the area under the artifact.

  1. "Bone-οn-Bone" surgical reconstruction of moderate severity, flexible single curve adolescent idiopathic scoliosis: continuing improvements of the technique and results in three scoliosis centers after almost twenty years of use.

    PubMed

    Gaines, Robert W; Min, Kan; Zarzycki, Daniel

    2015-01-01

    The "bone-on-bone" reconstruction for adolescent idiopathic scoliosis is reviewed in this article. Extensive use over the past 18 years has identified it's functional benefits outstanding clinical results, and very limited complications. This is an extensive update of it's application, since it's introduction, 18 years ago. PMID:26000031

  2. Fracture toughness and compressive properties of cancellous bone at the head of the femur and relationships to non-invasive skeletal assessment measurements.

    PubMed

    Cook, R B; Curwen, C; Tasker, T; Zioupos, P

    2010-11-01

    Osteoporosis defines a causal relationship between reduced bone density, reduced mechanical competence of the bone tissue of the sufferers and concomitantly an increased risk of fracture in life. The aims of the present study is: (1) to provide further evidence to support the use of Quantitative Ultrasound (QUS) results from peripheral sites to provide a prediction of the density of the proximal femur; and (2) to provide rational evidence for the well-proven ability of QUS to predict directly 'risk of fracture'. 20 femoral heads were obtained from 15 Caucasian females and 5 Caucasian males undergoing emergency surgery for a fractured neck of femur. QUS investigations of the calcaneus, proximal phalanx, distal radius and mid-shaft tibia were undertaken on the donors with 72h of surgery. 128 fracture toughness samples and 20 compression cores were manufactured and tested. Significant relationships were found between QUS parameters determined in vivo and the apparent density (g/cm(3)) of the tissue at the proximal femur and both the fracture toughness and strength determined in vitro from the same donor individual. In this study we relate QUS results obtained in vivo to the actual apparent density of bone tissue from the proximal femur, donated by the same individual, and the fracture toughness and compressive strength. The study demonstrates the ability of QUS investigations at peripheral sites to accurately predict the density of bone from the proximal femur and provides evidence to support the use of QUS to predict the 'risk of fracture' directly.

  3. Correlation between hyoid bone position and airway dimensions in Chinese adolescents by cone beam computed tomography analysis.

    PubMed

    Jiang, Y-Y

    2016-07-01

    This study aimed to investigate the correlation between upper airway dimensions and hyoid bone position in Chinese adolescents based on cone beam computed tomography (CBCT) images. CBCT images from a total of 254 study subjects were included. The upper airway and hyoid bone parameters were measured by Materialism's interactive medical image control system (MIMICS) v.16.01 (Materialise, Leuven, Belgium). The airway dimensions were evaluated in terms of volume, cross-sectional area (CSA), mean CSA, length, anteroposterior dimension of the cross-section (AP), lateral dimension of the cross-section (LAT), and LAT/AP ratio. The hyoid bone position was evaluated using eight linear parameters and two angular parameters. Facial characteristics were evaluated using three linear parameters and three angular parameters. Most hyoid bone position parameters (especially the distance between the hyoid bone and hard palate) were significantly associated with most airway dimension parameters. Significant correlations were also observed between the different facial characteristic parameters and hyoid bone position parameters. Most airway dimension parameters showed significant correlations with linear facial parameters, but they displayed significant correlations with only a few angular facial parameters. These findings provide an understanding of the static relationship between the hyoid bone position and airway dimensions, which may serve as a reference for surgeons before orthodontic or orthognathic surgery.

  4. Differential effect of age, gender and puberty on bone formation rate assessed by measurement of bone-specific alkaline phosphatase in healthy Italian children and adolescents.

    PubMed

    Mora, Stefano; Cafarelli, Laura; Erba, Paola; Puzzovio, Maria; Zamproni, Ilaria; Giacomet, Vania; Viganò, Alessandra

    2009-01-01

    Bones undergo intensive modeling during growth, a process involving both formation and resorption processes. Bone formation can be accurately monitored by measurements of bone-specific alkaline phosphatase (BAP) in serum. The lack of appropriate reference values has hampered the use of BAP in pediatric subjects. The purposes of the present study were to verify the effect of age, gender, and puberty on BAP concentration in healthy children, and to generate reference curves. Morning blood samples were collected from 239 healthy children and adolescents (113 boys), aged 4.5-20.9 years. Anthropometric measurements and pubertal stage were recorded. Blood samples were also obtained from 37 healthy young adults (13 men), aged 21.5-30.2 years. BAP concentration varied significantly with age, showing a peak at age 10-12 years in girls and 12-14 years in boys. Prepubertal concentration of BAP was six- to sevenfold higher than in healthy adults. We observed significantly higher BAP values at the beginning of puberty (stage II) compared to prepubertal stage in both sexes. The effect of puberty was independent from age and gender. We demonstrated that BAP serum concentration varies with age in children and adolescents, and we provided equations to calculate reference values. Because BAP concentrations vary markedly according to the pubertal stage, the values of BAP obtained in single patients should be compared to reference considering not only age and sex, but also the stage of pubertal development.

  5. Bone

    NASA Astrophysics Data System (ADS)

    Helmberger, Thomas K.; Hoffmann, Ralf-Thorsten

    The typical clinical signs in bone tumours are pain, destruction and destabilization, immobilization, neurologic deficits, and finally functional impairment. Primary malignant bone tumours are a rare entity, accounting for about 0.2% of all malignancies. Also benign primary bone tumours are in total rare and mostly asymptomatic. The most common symptomatic benign bone tumour is osteoid osteoma with an incidence of 1:2000.

  6. Abnormal Bone Mechanical and Structural Properties in Adolescent Idiopathic Scoliosis: A Study with Finite Element Analysis and Structural Model Index.

    PubMed

    Cheuk, K Y; Zhu, T Y; Yu, F W P; Hung, V W Y; Lee, K M; Qin, L; Cheng, J C Y; Lam, T P

    2015-10-01

    Previous studies found adolescent idiopathic scoliosis (AIS) is associated with low bone mineral density (BMD) and abnormal bone quality, whilst the association between AIS and their bone strength is unknown. From high-resolution peripheral quantitative computed tomography-generated images, bone mechanical properties can be evaluated with finite element analysis (FEA), and trabecular rod-plate configuration related to trabecular bone strength can be quantified by structure model index (SMI). This study aimed to compare trabecular configuration and bone mechanical properties between AIS and the controls. 95 AIS girls aged 12-14 years and 97 age- and gender-matched normal controls were recruited. Bilateral femoral necks and non-dominant distal radius were scanned by dual-energy X-ray absorptiometry for areal BMD and HR-pQCT for SMI and FEA, respectively. Subjects were further classified into osteopenic and non-osteopenic group based on their areal BMD. Bone mechanical properties (stiffness, failure load and apparent modulus) were calculated using FEA. Linear regression model was used for controlling age, physical activity and calcium intake. AIS was associated with lower failure load and apparent modulus after adjusting for age, whereas AIS was associated with lower apparent modulus after adjusting for all confounders. Osteopenic AIS was associated with more rod-like trabeculae when compared with non-osteopenic AIS, whereas no difference was detected between osteopenic and non-osteopenic controls. This might be the result of abnormal regulation and modulation of bone metabolism and bone modelling and remodelling in AIS which will warrant future studies with a longitudinal design to determine the significance of micro-architectural abnormalities in AIS.

  7. Does physical activity in adolescence have site-specific and sex-specific benefits on young adult bone size, content, and estimated strength?

    PubMed

    Duckham, Rachel L; Baxter-Jones, Adam D G; Johnston, James D; Vatanparast, Hassanali; Cooper, David; Kontulainen, Saija

    2014-02-01

    The long-term benefits of habitual physical activity during adolescence on adult bone structure and strength are poorly understood. We investigated whether physically active adolescents had greater bone size, density, content, and estimated bone strength in young adulthood when compared to their peers who were inactive during adolescence. Peripheral quantitative computed tomography (pQCT) was used to measure the tibia and radius of 122 (73 females) participants (age mean ± SD, 29.3 ± 2.3 years) of the Saskatchewan Pediatric Bone Mineral Accrual Study (PBMAS). Total bone area (ToA), cortical density (CoD), cortical area (CoA), cortical content (CoC), and estimated bone strength in torsion (SSIp ) and muscle area (MuA) were measured at the diaphyses (66% tibia and 65% radius). Total density (ToD), trabecular density (TrD), trabecular content (TrC), and estimated bone strength in compression (BSIc ) were measured at the distal ends (4%). Participants were grouped by their adolescent physical activity (PA) levels (inactive, average, and active) based on mean PA Z-scores obtained from serial questionnaire assessments completed during adolescence. We compared adult bone outcomes across adolescent PA groups in each sex using analysis of covariance followed by post hoc pairwise comparisons with Bonferroni adjustments. When adjusted for adult height, MuA, and PA, adult males who were more physically active than their peers in adolescence had 13% greater adjusted torsional bone strength (SSIp , p < 0.05) and 10% greater adjusted ToA (p < 0.05) at the tibia diaphysis. Females who were more active in adolescence had 10% larger adjusted CoA (p < 0.05), 12% greater adjusted CoC (p < 0.05) at the tibia diaphysis, and 3% greater adjusted TrC (p < 0.05) at the distal tibia when compared to their inactive peers. Benefits to tibia bone size, content, and strength in those who were more active during adolescence seemed to persist into young adulthood

  8. Effects of hindlimb unloading and ionizing radiation on skeletal muscle resistance artery vasodilation and its relation to cancellous bone in mice.

    PubMed

    Prisby, Rhonda D; Alwood, Joshua S; Behnke, Brad J; Stabley, John N; McCullough, Danielle J; Ghosh, Payal; Globus, Ruth K; Delp, Michael D

    2016-01-15

    Spaceflight has profound effects on vascular function as a result of weightlessness that may be further compounded by radiation exposure. The purpose of the present study was to assess the individual and combined effects of hindlimb unloading (HU) and radiation (Rad) on vasodilator responses in the skeletal muscle vasculature. Adult male C57BL/6J mice were randomized to one of four groups: control (Con), HU (tail suspension for 15 days), Rad (200 cGy of (137)Cs), and HU-Rad (15-day tail suspension and 200 cGy of (137)Cs). Endothelium-dependent vasodilation of gastrocnemius feed arteries was assessed in vitro using acetylcholine (ACh, 10(-9)-10(-4) M) and inhibitors of nitric oxide synthase (NOS) and cyclooxygenase (COX). Endothelium-independent vasodilation was assessed using Dea-NONOate (10(-9)-10(-4) M). Endothelium-dependent and -independent vasodilator responses were impaired relative to Con responses in all treatment groups; however, there was no further impairment from the combination of treatments (HU-Rad) relative to that in the HU and Rad groups. The NOS-mediated contribution to endothelium-dependent vasodilation was depressed with HU and Rad. This impairment in NOS signaling may have been partially compensated for by an enhancement of PGI2-mediated dilation. Changes in endothelium-dependent vasodilation were also associated with decrements in trabecular bone volume in the proximal tibia metaphysis. These data demonstrate that the simulated space environment (i.e., radiation exposure and unloading of muscle and bone) significantly impairs skeletal muscle artery vasodilation, mediated through endothelium-dependent reductions in NOS signaling and decrements in vascular smooth muscle cell responsiveness to NO.

  9. DXA surrogates for visceral fat are inversely associated with bone density measures in adolescent athletes with menstrual dysfunction

    PubMed Central

    Ackerman, Kathryn E.; Davis, Brittany; Jacoby, Leah; Misra, Madhusmita

    2013-01-01

    Objective Lean mass is associated with bone mineral density (BMD) in athletes, attributable to the anabolic pull of muscle on bone. Fat mass is also important, and subcutaneous fat positively and visceral fat negatively correlates with BMD in obese adolescents. The contribution of regional body composition to low BMD in amenorrheic athletes (AA) has not been elucidated. We hypothesized that in adolescent athletes (runners), BMD is associated positively with total fat (surrogate for subcutaneous fat) and lean mass, and inversely with percent trunk fat and trunk-to-extremity fat ratio (surrogates for visceral fat). Design Cross-sectional study. Subjects and methods We examined BMD and body composition using dual energy X-ray absorptiometry (DXA) in 21 AA and 19 eumenorrheic athletes (EA) (12–18 years) (runners). We report total hip and height-adjusted BMD [lumbar bone mineral apparent density (LBMAD) and whole body bone mineral content/height (WBBMC/Ht)]. Results AA had lower BMD than EA. Lean mass was less strongly associated with hip BMD in AA than EA; fat mass was positively associated with LBMAD in EA. Percent trunk fat and trunk-to-extremity fat ratio were inversely associated with lumbar and WB measures in AA. In a regression model, lean and fat mass were positively, and percent trunk fat and trunk-to-extremity fat ratio negatively associated with LBMAD and WBBMC/Ht for all athletes, even after controlling for serum estradiol. Conclusions DXA surrogates for visceral fat are inversely associated with bone density in athletes. PMID:21932588

  10. Long-Term Neurotoxicity of Chemotherapy in Adolescents and Young Adults Treated for Bone and Soft Tissue Sarcomas

    PubMed Central

    Connolly, Sean; Latoufis, Christos; Eagle, Karen; Ash, Catherine M.; Fowler, Clare; Souhami, Robert L.

    1998-01-01

    Purpose. To study the long-term neurotoxicity of chemotherapy in adolescents and young adults treated for bone and soft tissue sarcomas. Patients and Methods. Thirty-six adolescents and young adults (median age 17 years) were examined following chemotherapy for bone and soft tissue sarcomas. Twenty-nine (29/36) had received cisplatin (median 400 mg/m2), 15/36 ifosfamide (median 20 g/m2), and 12/36 vincristine (median 16 mg). Neurotoxicity was assessed at a median of 8 months (range, 1–54 months) after completion of chemotherapy by clinical examination, nerve conduction studies, audiograms and autonomic function tests. The same nerve conduction studies were carried out in 20 normal volunteers to define normal ranges in this age group. Results. Sixteen patients (44%) had a significant reduction in deep tendon reflexes, and this clinical parameter correlated well with abnormalities detected in nerve conduction studies. Vibration perception threshold (VPT) was raised in 20/36 patients (55%) and this was the most sensitive single test in the assessment of neuropathy. There was a significant correlation between VPT and cumulative cisplatin dose received in mg/m-2 (r=0.607, p<0.01). Ten of 29 patients (35%) had abnormal nerve conduction studies with a pattern characteristic of sensory axonal neuropathy. No patient complained of auditory symptoms, but minor high tone hearing loss was detected by audiograms in 5/28 patients who had received cisplatin. No patients had symptoms of autonomic neuropathy, but autonomic function tests showed minor abnormalities in 4/22 patients tested, and all had received cisplatin. Conclusions. This study demonstrates significant, although asymptomatic, long-term neurotoxicity of cisplatin in adolescents and young adults receiving chemotherapy for bone and soft tissue sarcomas. Follow-up studies are planned to assess whether these neurological deficits improve with time. PMID:18521240

  11. Adaptive cancellation techniques

    NASA Astrophysics Data System (ADS)

    1983-11-01

    An adaptive signal canceller has been evaluated for the enhancement of pulse signal reception during the transmission of a high power ECM jamming signal. The canceller design is based on the use of DRFM(Digital RF Memory) technology as part of an adaptive multiple tapped delay line. The study includes analysis of relationship of tap spacing and waveform bandwidth, survey of related documents in areas of sidelobe cancellers, transversal equalizers, and adaptive filters, and derivation of control equations and corresponding control processes. The simulation of overall processes included geometric analysis of the multibeam transmitting antenna, multiple reflection sources and the receiving antenna; waveforms, tap spacings and bandwidths; and alternate control algorithms. Conclusions are provided regarding practical system control algorithms, design characteristics and limitations.

  12. Top 10 Research Questions Related to Physical Activity and Bone Health in Children and Adolescents

    ERIC Educational Resources Information Center

    Janz, Kathleen F.; Thomas, David Q.; Ford, M. Allison; Williams, Skip M.

    2015-01-01

    Evidence strongly supports a positive, causal effect of physical activity on bone strength and suggests long-term benefits of childhood physical activity to the prevention of osteoporosis. The contribution of healthy bone development in youth is likely to be as important to fracture prevention as the amount of late adulthood bone loss. Families,…

  13. Influence of bone parameters on peri-implant bone strain distribution in the posterior mandible

    PubMed Central

    Yamamoto, Kazuhiko; Kawakami, Masayoshi; Horita, Satoshi; Murakami, Kazuhiro; Kirita, Tadaaki

    2015-01-01

    Objectives: The success rate of dental implants depends on the type of bone at the implant site. The purpose of the present study was to investigate the effects of the bone parameters at the implant-placement site on peri-implant bone strain distributions. Study Design: The morphologies and bone densities of seventy-five potential implant sites in the posterior mandible were measured using computed tomography (CT). Based on the CT data, we defined bone parameters (low and high in terms of cancellous-bone density and crestal-cortical bone density, and thin and thick in terms of crestal-cortical bone thickness), and we constructed finite-element models simulating the various bone types. A buccolingual oblique load of 200 N was applied to the top of the abutment. The von Mises equivalent (EQV) strains in the crestal-cortical bone and in the cancellous bone around the implant were calculated. Results: Cancellous-bone density greatly affected the maximum EQV strain regardless of the density and thickness of the crestal cortical-bone. The maximum EQV strains in the crestal cortical-bone and the cancellous bone in the low-density cancellous-bone models (of 150 Hounsfield units (HU) were 1.56 to 2.62-fold and 3.49 to 5.31-fold higher than those in the high-density cancellous-bone models (of 850 HU), respectively. The crestal cortical-bone density affected the maximum EQV strains in the crestal cortical-bone and in the cancellous bone in the low-density cancellous-bone models. The crestal cortical-bone thickness affected the maximum EQV strains in the cancellous bone and in the crestal cortical-bone in the low-density cancellous-bone models. Conclusions: Our results confirm the importance of bone types for the peri-implant bone strain distribution. Cancellous-bone density may be a critical factor for peri-implant bone strain. Key words:Dental implant, bone density, finite-element analysis. PMID:25129251

  14. A Piece of the Puzzle: The Bone Health Index of the BoneXpert Software Reflects Cortical Bone Mineral Density in Pediatric and Adolescent Patients

    PubMed Central

    Schündeln, Michael M.; Marschke, Laura; Bauer, Jens J.; Hauffa, Pia K.; Schweiger, Bernd; Führer-Sakel, Dagmar; Lahner, Harald; Poeppel, Thorsten D.; Kiewert, Cordula; Hauffa, Berthold P.; Grasemann, Corinna

    2016-01-01

    Introduction Suspected osteopathology in chronically ill children often necessitates the assessment of bone mineral density. The most frequently used methods are dual-energy X-ray-absorption (DXA) and peripheral quantitative computed tomography (pQCT). The BoneXpert software provides an automated radiogrammatic method to assess skeletal age from digitalized X-rays of the left hand. Furthermore, the program calculates the Bone Health Index (BHI), a measure of cortical thickness and mineralization, which is obtained from indices of three metacarpal bones. In our study, we analyzed the manner in which BHI information provided by BoneXpert compares with DXA or pQCT measurements in youths. Study Design The BHI was retrospectively obtained using digitalized X-rays of the left hand and compared with the results of 203 corresponding DXA readings (Lunar Prodigy, GE Healthcare) of the lumbar vertebrae and femur as well as 117 pQCT readings (XCT 900, Stratec) of the distal radius. Results The BHI values showed a strong positive correlation with the DXA readings at each and all lumbar vertebrae (L1 –L4: r = 0.73; P < 0.0001). The age-adjusted Z-score of L1 –L4 and the height-adjusted score showed a positive correlation with the BHI-SDS (standard deviation score, r = 0.23; P < 0.002 and r = 0.27; P < 0.001, respectively). Total bone mineral density, as assessed via pQCT, also positively correlated with the BHI (r = 0.39; P < 0.0001), but the trabecular values displayed only a weak correlation. Conclusions The BHI obtained using BoneXpert can be a useful parameter in the assessment of bone health in children in most cases. This technique provides observer-independent information on cortical thickness and mineralization based on X-ray imaging of the hands. PMID:27014874

  15. A prospective comparison of bone density in adolescent girls receiving depot medroxyprogesterone acetate (Depo-Provera), levonorgestrel (Norplant), or oral contraceptives.

    PubMed

    Cromer, B A; Blair, J M; Mahan, J D; Zibners, L; Naumovski, Z

    1996-11-01

    In Ohio, data on 31 postmenarcheal women, 12-21 years old and using hormonal contraception (Norplant = 7, Depo Provera = 15, and oral contraceptives [OCs] = 9) were compared with data on 17 controls of similar age to prospectively examine lumbar bone density in girls before and after 1 and 2 years of hormonal contraceptive use and to compare the results with young women not using hormonal contraceptives. The subjects attended a general adolescent clinic at Children's Hospital in Columbus. There was an insufficient number of OC users at 2 years, so they were not included in second year analyses. Initial height and weight were significantly associated with bone density values (p 0.05). Weight accounted for the most variance both at baseline (p 0.001) and after 1 year of treatment (p 0.01). At baseline and 1 year, bone density values between patient groups were not significantly different. At 2 years, however, Norplant users had higher bone density than Depo- Provera users and controls (1.308 vs. 1.004 and 1.087, respectively; p 0.01). After 1 year, Depo-Provera users experienced a decrease (1.53%) in bone density while Norplant users, OC users, and controls experienced an increase in bone density (2.46%, 1.52%, and 2.85%, respectively). The change in bone density between Depo-Provera users and controls was significant (p 0.02). At 2 years, Depo Provera users experienced a decrease in bone density while Norplant users and controls experienced an increase (-3.12% vs. 9.33% and 9.49%, respectively; p 0.0001). This study is important because 50% of adult bone mass is accrued during adolescence. In fact, bone mass peaks during adolescence. It is not known whether bone loss during Depo Provera use is reversible after treatment discontinuation. These findings show that Depo Provera inhibits skeletal bone mineralization in adolescents, at least temporarily, while Norplant and OCs appear to increase bone density.

  16. The use of femoral struts and impacted cancellous bone allograft in patients with severe femoral bone loss who undergo revision total hip replacement: a three- to nine-year follow-up.

    PubMed

    Buttaro, M A; Costantini, J; Comba, F; Piccaluga, F

    2012-02-01

    We determined the midterm survival, incidence of peri-prosthetic fracture and the enhancement of the width of the femur when combining struts and impacted bone allografts in 24 patients (25 hips) with severe femoral bone loss who underwent revision hip surgery. The pre-operative diagnosis was aseptic loosening in 16 hips, second-stage reconstruction in seven, peri-prosthetic fracture in one and stem fracture in one hip. A total of 14 hips presented with an Endoklinik grade 4 defect and 11 hips a grade 3 defect. The mean pre-operative Merle D'Aubigné and Postel score was 5.5 points (1 to 8). The survivorship was 96% (95% confidence interval 72 to 98) at a mean of 54.5 months (36 to 109). The mean functional score was 17.3 points (16 to 18). One patient in which the strut did not completely bypass the femoral defect was further revised using a long cemented stem due to peri-prosthetic fracture at six months post-operatively. The mean subsidence of the stem was 1.6 mm (1 to 3). There was no evidence of osteolysis, resorption or radiolucencies during follow-up in any hip. Femoral width was enhanced by a mean of 41% (19% to 82%). A total of 24 hips had partial or complete bridging of the strut allografts. This combined biological method was associated with a favourable survivorship, a low incidence of peri-prosthetic fracture and enhancement of the width of the femur in revision total hip replacement in patients with severe proximal femoral bone loss.

  17. [Value of physical activity for proper bone mass and bone mineral density attaining in children and adolescents].

    PubMed

    Bolanowski, Marek; Basiak, Aleksander; Bolanowski, Janusz; Sutkowski, Krzysztof

    2008-01-01

    Physical activity is an important factor for healthy life of the humans. Its significance regards mostly the developmental age, when natural mobility of the youth prones to the proper growing of the skeleton and is important in the prevention and therapy of many diseases. The advantageous effect of regular physical activity and different sport disciplines on bone mass and density is described. In the young age, puberty is an ideal moment for attaining the maximal bone mass and density gain due to physical exercising. The possible harmful effect of exaggerated physical activity has been shown. It is connected with hormonal disorders - secondary amenorrhea, delay of menarche, increased injuries and BMD loss together with significant body mass reduction.

  18. Bone mineral density reduction in adolescents with systemic erythematosus lupus: association with lack of vitamin D supplementation.

    PubMed

    Caetano, M; Terreri, M T; Ortiz, T; Pinheiro, M; Souza, F; Sarni, R

    2015-12-01

    The aim of this study is to evaluate body composition and the bone mineral density in female adolescents with juvenile systemic lupus erythematosus. Body composition (BC) and bone mineral density (BMD) were evaluated in an observational cohort study with 35 postmenarcheal adolescent females. The variables studied were as follows: current and cumulative corticosteroid dose, intake of supplements containing calcium and vitamin D, 24-h proteinuria, body mass index (BMI), and height for age (Z-score). BC was assessed using dual-energy X-ray absorptiometry (DXA) at two time points (median interval of 1.2 years). The fat mass index (FMI = fat mass in kilograms divided by the height in meters squared) and lean mass index (LMI = lean mass in kilograms divided by the height in meters squared) were calculated based on the DXA results. BMD was classified according to the International Society of Clinical Densitometry (low BMD for chronological age < -2.0 standard deviations). .The mean age of the subjects was 15.4 ± 1.8 years. Of patients, 54.3 % were normal weight, 22.8 % were overweight, 22.8 % were obese, and 8.6 % had short stature. Low BMD for chronological age was observed in 42.8 % of patients, and 60 % were not taking vitamin D. There was no significant difference between the two time points with respect to FMI, LMI, or body mass index Z-score (ZBMI); however, BMD has decreased significantly (p = 0.011). There was an association between not taking a vitamin D supplement and decreased BMD (p = 0.027). Almost half of the patients had altered nutritional status. The BMD decrease in adolescents with juvenile systemic lupus erythematosus (JSLE) was associated with the lack of vitamin D supplementation, highlighting the importance of well-defined vitamin D supplementation protocols.

  19. Influence of ghrelin and adipocytokines on bone mineral density in adolescent female athletes with amenorrhea and eumenorrheic athletes.

    PubMed

    Russell, Melissa; Misra, Madhusmita

    2010-01-01

    Adolescent female athletes are at increased risk for low bone mineral density (BMD) secondary to exercise-induced hypogonadism. Of particular concern is that the adolescent years are also a critical time for bone accrual, and deficits incurred during this period could lead to suboptimal peak bone mass acquisition and subsequent fracture risk in later life. Although weight-bearing exercise is typically associated with an increase in BMD, amenorrheic athletes have lower BMD than eumenorrheic athletes and nonathletic controls as a consequence of low energy availability and subsequent hypogonadism. It is important to recognize that critical interactions exist between net energy availability and the hypothalamo-pituitary-gonadal (H-P-G) axis that are key to the development of a hypogonadal state when energy intake cannot keep pace with expenditure. While the link between energy availability and gonadtotropin pulsatility patterns is well established, the actual metabolic signals that link the two are less clear. Decreased energy availability in athletes is associated with decreases in fat mass, and alterations in adipokines (such as leptin and adiponectin) and fat-regulated hormones (such as ghrelin and peptide YY). These hormones impact the H-P-G axis in animal models, and it is possible that in athletes alterations in fat-related hormones signal the state of energy availability to the hypothalamus and contribute to suppression of gonadotropin pulsatility, hypothalamic amenorrhea and consequent decreased BMD. A better understanding of pathways linking low energy availability with functional hypothalamic amenorrhea and low BMD is critical for the development of future therapeutic strategies addressing these issues in amenorrheic athletes. PMID:20956863

  20. Structural strength of cancellous specimens from bovine femur under cyclic compression

    PubMed Central

    Endo, Kaori; Yamada, Satoshi; Todoh, Masahiro; Takahata, Masahiko; Iwasaki, Norimasa

    2016-01-01

    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 baseline cancellous

  1. A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage.

    PubMed

    Yamagata, Toru; Naito, Kentaro; Arima, Hironori; Yoshimura, Masaki; Ohata, Kenji; Takami, Toshihiro

    2016-07-01

    Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of β-tricalcium phosphate (β-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with β-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the β-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the β-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion. PMID:27098659

  2. A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage.

    PubMed

    Yamagata, Toru; Naito, Kentaro; Arima, Hironori; Yoshimura, Masaki; Ohata, Kenji; Takami, Toshihiro

    2016-07-01

    Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of β-tricalcium phosphate (β-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with β-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the β-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the β-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion.

  3. Hip bone trabecular architecture shows uniquely distinctive locomotor behaviour in South African australopithecines.

    PubMed

    Macchiarelli, R; Bondioli, L; Galichon, V; Tobias, P V

    1999-02-01

    Cancellous bone retains structural and behavioural properties which are time and strain-rate dependent. As the orientation of the trabeculae (trajectories) follows the direction of the principal strains imposed by daily loadings, habitual postural and locomotor behaviours are responsible for a variety of trabecular architectures and site-specific textural arrangements of the pelvic cancellous network. With respect to the great ape condition, the human trabecular pattern is characterized by a distinctive ilioischial bundle, an undivided sacropubic bundle, and a full diagonal crossing (approximately 100 degrees) over the acetabulum between the ilioischial and the sacropubic bundles. Advanced digital image processing (DIP) of hip bone radiographs has revealed that adolescent and adult South African australopithecines retained an incompletely developed human-like trabecular pattern associated with gait-related features that are unique among the extant primates. PMID:10068067

  4. Hip bone trabecular architecture shows uniquely distinctive locomotor behaviour in South African australopithecines.

    PubMed

    Macchiarelli, R; Bondioli, L; Galichon, V; Tobias, P V

    1999-02-01

    Cancellous bone retains structural and behavioural properties which are time and strain-rate dependent. As the orientation of the trabeculae (trajectories) follows the direction of the principal strains imposed by daily loadings, habitual postural and locomotor behaviours are responsible for a variety of trabecular architectures and site-specific textural arrangements of the pelvic cancellous network. With respect to the great ape condition, the human trabecular pattern is characterized by a distinctive ilioischial bundle, an undivided sacropubic bundle, and a full diagonal crossing (approximately 100 degrees) over the acetabulum between the ilioischial and the sacropubic bundles. Advanced digital image processing (DIP) of hip bone radiographs has revealed that adolescent and adult South African australopithecines retained an incompletely developed human-like trabecular pattern associated with gait-related features that are unique among the extant primates.

  5. Postal cancellation from spaceport

    NASA Astrophysics Data System (ADS)

    The John F. Kennedy Space Center, in cooperation with the United States Postal Service, is offering a cancellation service to interested philatelists for the space flight programs at Kennedy.Philatelists who wish to avail themselves of this service may do so by following the procedures outlined below: Specify the event for which you wish this service. There is a limit of five covers per customer per event.

  6. Material Properties of Inorganic Bovine Cancellous Bovine: Nukbone

    NASA Astrophysics Data System (ADS)

    Piña, Cristina; Palma, Benito; Munguía, Nadia

    2006-09-01

    In this work, inorganic cancellous bovine bone implants prepared in the Instituto de Investigaciones en Materiales — UNAM were characterized. Elementary chemical analysis was made, toxic elements concentration were measured and the content of organic matter also. These implants fulfill all the requirements of the ASTM standards, and therefore it is possible their use in medical applications.

  7. Bone Strength and Structural Deficits in Children and Adolescents With a Distal Forearm Fracture Resulting From Mild Trauma

    PubMed Central

    Farr, Joshua N; Amin, Shreyasee; Melton, L Joseph; Kirmani, Salman; McCready, Louise K; Atkinson, Elizabeth J; Müller, Ralph; Khosla, Sundeep

    2014-01-01

    Although distal forearm fractures (DFFs) are common during childhood and adolescence, it is unclear whether they reflect underlying skeletal deficits or are simply a consequence of the usual physical activities, and associated trauma, during growth. Therefore, we examined whether a recent DFF, resulting from mild or moderate trauma, is related to deficits in bone strength and cortical and trabecular bone macro- and microstructure compared with nonfracture controls. High-resolution peripheral quantitative computed tomography was used to assess micro-finite element-derived bone strength (ie, failure load) and to measure cortical and trabecular bone parameters at the distal radius and tibia in 115 boys and girls with a recent (<1 year) DFF and 108 nonfracture controls aged 8 to 15 years. Trauma levels (mild versus moderate) were assigned based on a validated classification scheme. Compared with sex-matched controls, boys and girls with a mild-trauma DFF (eg, fall from standing height) showed significant deficits at the distal radius in failure load (−13% and −11%, respectively; p<0.05) and had higher (“worse”) fall load-to-strength ratios (both þ10%; p<0.05 for boys and p=0.06 for girls). In addition, boys and girls with a mild-trauma DFF had significant reductions in cortical area (−26% and −23%, respectively; p<0.01) and cortical thickness (−14% and −13%, respectively; p<0.01) compared with controls. The skeletal deficits in the mild-trauma DFF patients were generalized, as similar changes were present at the distal tibia. By contrast, both boys and girls with a moderate-trauma DFF (eg, fall from a bicycle) had virtually identical values for all of the measured bone parameters compared with controls. In conclusion, DFFs during growth have two distinct etiologies: those owing to underlying skeletal deficits leading to fractures with mild trauma versus those owing to more significant trauma in the setting of normal bone strength. PMID:23959563

  8. Decreased levels of physical activity in adolescents with down syndrome are related with low bone mineral density: a cross-sectional study

    PubMed Central

    2013-01-01

    Background Down syndrome (DS) has been described as one of the main contributors for low bone mineral density (BMD). Physical activity (PA) is a key factor in skeletal health and thus, PA levels might be associated to the risk of developing osteoporosis. Therefore, the aims were (1) to describe PA patterns in adolescents with DS compared to their counterparts and (2) to determine the relationships between PA and the risk of having low bone mass in adolescents with DS. Methods Nineteen adolescents (10 girls) with DS and 14 without disabilities (7 girls) participated in the study. Minutes in different PA intensities were objectively assessed with accelerometers (ActiTrainer). Moreover adolescents with DS were classified into PA tertiles taking into account the amount of total minutes of PA at any intensity, resulting in those performing low, medium or high of PA (lowPA, medPA and highPA). BMD was measured at the whole body, hip and lumbar spine with dual-energy X-ray absorptiometry and the BMD Z-score was calculated for each region taking into account age- and sex-matched reference data. Student’s unpaired t-tests and analysis of covariance were used to compare variables between different conditions (DS vs. control) and PA levels (low, medium and high). Results None of the adolescents with DS achieved the minimum of 60 min of daily moderate to vigorous PA (VPA) intensity recommended by PA guidelines; adolescents with DS group spent less time in sedentary and in VPA and more time in light PA than those without DS (p < 0.05). Adolescents with DS showed lower BMD Z-score values than those without (p < 0.05). Those adolescents with DS allocated in the lowPA tertile showed significant lower BMD Z-score at the hip and a general tendency towards lower BMD Z-score was found at whole body and lumbar spine compared to those in highPA tertile and (p < 0.05). Conclusions Adolescents with DS in the highPA tertile showed lower risk of developing future osteoporosis by having

  9. Tibial tubercle avulsion fractures in adolescent basketball players.

    PubMed

    Jakoi, Andre; Freidl, Michael; Old, Andrew; Javandel, Mitra; Tom, James; Realyvasquez, Juan

    2012-08-01

    Tibial tubercle avulsion fractures most commonly occur in adolescent boys and usually result from pushing off or landing while jumping. These fractures are relatively uncommon but can have a significant functional effect. The purpose of this study was to determine the long-term outcome with return to play in 8 adolescent basketball players with at least 4 years of postoperative reconditioning. Results with return to play at the preinjury level are favorable after treatment of acute tibial avulsion fractures in adolescent basketball players. Long-term outcome was excellent in all patients regardless of fracture type. Open reduction and internal fixation using 1 or 2 cancellous bone screws achieved union in all cases.

  10. Alcohol consumption inhibits bone growth and development in young actively growing rats.

    PubMed

    Sampson, H W; Perks, N; Champney, T H; DeFee, B

    1996-11-01

    Adolescence is an age of widespread alcohol abuse, but the effect of alcohol consumption on bone formation has not been studied in the young population. This study addresses the effect of alcohol on the early phases of bone growth and development in an animal model. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin substituted calories supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae (primarily cancellous bone) and femora (primarily cortical bone) were removed for analysis after 2, 4, 6, or 8 weeks on the diets. Serum was collected for analysis of calcium levels, osteocalcin, corticosterone, growth hormone, parathyroid hormone, and 25-hydroxyvitamin D. The most rapid weight gain occurred between 6 and 8 weeks of age, it was significantly delayed in alcohol and pair-fed animals. Almost all morphological parameters of bone were lower in the alcohol groups. No significant difference in serum calcium levels, osteocalcin, or growth hormone levels were found, and small difference in calciotropic hormone levels was found between groups. The results indicated that chronic alcohol consumption during the age of bone development reduces bone density and peak bone mass in both cortical and cancellous bone. The mechanism whereby this effect occurs is not fully understood, but, our results suggest that the negative impact of alcohol on growing bone is not due to the secondary effects of altered bone mineral regulating hormones.

  11. Aneurysmal bone cyst involving the metacarpal bone in a child.

    PubMed

    Song, Kwang Soon; Lee, Si Wook; Bae, Ki Cheor; Sohn, Eun Seok

    2015-03-01

    Aneurysmal bone cysts associated with tubular bones of the hand occur rarely and require particular diagnostic and therapeutic management techniques. While optimal treatment has not been established, accepted treatments range from aggressive radical treatment, including en bloc resection and excision diaphysectomy with strut bone grafting, to relatively simple techniques, such as thorough curettage followed by bone graft. Aggressive treatment approaches may be optimal for the cases with articular surface involvement, full-bone invasion of the phalanx or metacarpal, or more than 1 recurrence. We report a monocentric case of aneurysmal bone cysts involving metacarpal bone in a child who achieved favorable outcome with curettage and morselized cancellous bone grafts. PMID:25750953

  12. [A case of adolescent adrenoleukodystrophy with clinical improvement after allogeneic bone marrow transplantation (allo-BMT)].

    PubMed

    Tsujii, Tomomi; Kinoshita, Masako; Tomimoto, Hidekazu; Hitomi, Takefumi; Okazaki, Toshirou; Uchiyama, Taku; Shibasaki, Hiroshi

    2004-10-01

    We reported a case of adolescent type adrenoleukodystrophy. A 20-year old man noticed slight hemiparesis on his right side. After admission, high level of serum VCLFA and ACTH and a point mutation in ALDP codon 606 were recognized along with white matter lesions in the left medulla, basal ganglia, splenium of the corpus callosum on brain MRI. Then we diagnosed the patient as having adolescent type adrenoleukodystrophy. We started Lorenzo's oil and seaching for BMT donor. Six months later, he received allo-BMT at our hospital. His clinical symptoms gradually deteriorated during waiting allo-BMT, and just before allo-BMT, right hemiparesis, gait disturbance, exaggerated deep tendon reflexes on his right side, right lower quadrantanopia and mild cognitive deterioration. Two months after allo-BMT, gait disturbance and right hemiparesis were alleviated. We also observed improvement of abnormal findings on brain MRI and magnetic stimulation. We believed that allo-BMT is effective for the treatment of adolescent type adrenoleukodystrophy.

  13. 43 CFR 3601.62 - Cancellation procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Disposal; General Provisions Contract and Permit Cancellation § 3601.62 Cancellation procedure....

  14. 43 CFR 3601.62 - Cancellation procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Disposal; General Provisions Contract and Permit Cancellation § 3601.62 Cancellation procedure....

  15. [Ultrasound bone densitometry in children and adolescents; Italian refence curves with multi-site device (Omnisense)].

    PubMed

    Pedrotti, L; Mora, R; Bertani, B; Tuvo, G; Galli, G B; Pazzano, S; Quattrini, F; Crivellari, I

    2007-01-01

    The values of bone density represent one of the best parameters for the prediction of the risk of fracture in the adult. Since the peak of bone mass depends over that on genetic factors also on modifiable environmental factors, the evaluation of the state of bone health in paediatric populations has assumed great importance; the ultrasound techniques seem to represent a potential alternative to DXA and QTC. Using Omnisense device (Omnisense, Sunlight Ultrasound Technologies) we have evaluated the bone strength in a champion of 652 children and teen-agers aged 6-18 (328 females, 324 males). The measurements have been made at the distal third of the radius and midshaft tibia. The purpose has been to record the values of SOS in a healthy paediatric population, building a normal database and to find a correlation between the SOS values and anthropometric data, dietary factors and physical activity. The comparison with an analogous study conducted by other Authors prompted us to conclude that in the paediatric population the construction of proper curves of reference, with which to compare the data of the patients, is essential to avoid errors in the evaluation of bone density, in agreement with how much already underlined in literature. Besides a correct interpretation of the data obtained with ultrasounds systems asks for a change of the thresholds values established by the OMS for the diagnosis of osteopenia/osteoporosis with the DXA. As already happened for the adult population in children also it will be therefore necessary to compare a great number of pathological subjects with the normal database, establishing so the new values of Z-Score and giving a clinical meaning to the effected measurements.

  16. Daily Parathyroid Hormone 1-34 Replacement Therapy for Hypoparathyroidism Induces Marked Changes in Bone Turnover and Structure

    PubMed Central

    Gafni, Rachel I.; Brahim, Jaime S.; Andreopoulou, Panagiota; Bhattacharyya, Nisan; Kelly, Marilyn H.; Brillante, Beth A.; Reynolds, James C.; Zhou, Hua; Dempster, David W.; Collins, Michael T.

    2012-01-01

    Parathyroid hormone (PTH) has variable actions on bone. Chronically increased PTH is catabolic leading to osteoporosis, yet intermittent administration is anabolic and increases bone mass. PTH deficiency is associated with decreased bone remodeling and increased bone mass. However, the effects of PTH replacement therapy on bone in hypoparathyroidism are not well known. We discontinued calcitriol therapy and treated five hypoparathyroid subjects (2 adults and 3 adolescents) with synthetic human PTH 1-34 (hPTH 1-34), injected 2-3 times daily for 18 months, with doses individualized to maintain serum calcium at 1.9-2.25 mmol/L. Biochemical markers and bone density (BMD) were assessed every 6 months; iliac-crest biopsies were performed before and after 1 year of treatment. hPTH 1-34 therapy significantly increased bone markers to supranormal levels. Histomorphometry revealed that treatment dramatically increased cancellous bone volume and trabecular number and decreased trabecular separation. Changes in trabecular width were variable, suggesting that the increase in trabecular number was due to the observed intratrabecular tunneling. Cortical width remained unchanged, however, hPTH 1-34 treatment increased cortical porosity. Cancellous bone remodeling was also stimulated, inducing significant changes in osteoid, mineralizing surface, and bone formation rate. Similar changes were seen in endocortical and intracortical remodeling. BMD Z-scores were unchanged at the spine and femoral neck. Total hip Z-scores increased, however, total body BMD Z-scores decreased during the first 6 months of treatment and then stabilized, remaining significantly decreased compared to baseline. Radial Z-scores also decreased with treatment; this was most pronounced in the growing adolescent. Daily hPTH 1-34 therapy for hypoparathyroidism stimulated bone turnover, increased bone volume, and altered bone structure in the iliac crest. These findings suggest that treatment with hPTH 1-34 in

  17. Trabecular and cortical bone deficits are present in children and adolescents with cystic fibrosis.

    PubMed

    Kelly, Andrea; Schall, Joan; Stallings, Virginia A; Zemel, Babette S

    2016-09-01

    Osteopenia and increased fracture rates are well-recognized in adults with CF, but neither the specific contributions of cortical and trabecular bone deficits to bone fragility nor their presence in youth with CF are well-characterized. This study sought to characterize cortical and trabecular volumetric bone mineral density (vBMD), geometry, and biomechanical competence in children with CF and determine their relationship to growth, body composition, and disease severity. Peripheral quantitative computerized tomography (pQCT) measures of total, cortical, and trabecular vBMD, cortical, muscle, and fat cross-sectional areas (CSA), periosteal and endosteal circumferences, and the polar unweighted section modulus (Zp) of the tibia were converted to age- and tibial length-adjusted Z-scores in 97 CF and 199 healthy children (aged 8-21y). Effects of body composition and pulmonary function (forced expiratory volume in 1s, FEV1) upon pQCT outcomes were determined using linear regression. Children with CF (FEV1%-predicted: 84.4+19.7) had lower weight-, height-, BMI-, and whole body lean mass (LBM)-Z and tibial length. Females with CF had lower (p<0.01) total and trabecular vBMD; cortical, muscle, and fat CSA; Zp and periosteal circumference than females in the healthy reference group. These bone differences persisted after adjustment for BMI-Z and to a great extent following adjustment for muscle CSA. Males with CF had lower (p<0.01) cortical, muscle, and fat CSA and their trabecular vBMD deficit approached significance (p=0.069). Deficits were attenuated by adjustment for BMI-Z and to a greater extent adjustment for muscle CSA-Z. The relationship between FEV1%-predicted and pQCT outcomes persisted only in males following adjustment for age and BMI-Z. The CF cohort had lower tibial muscle CSA than expected for their LBM. In this relatively healthy, young CF cohort, deficits in trabecular and multiple cortical bone parameters were present. In females, deficits were greater

  18. The efficacy of mineralized allograft cortical and cancellous chips in maxillary sinus augmentations.

    PubMed

    Nevins, Myron; Parma-Benfenati, Stefano; Janke, Ulrich W; Kleyer, Aimé; Rasperini, Giulio; Tinti, Carlo; Schupbach, Peter; Kim, David M

    2014-01-01

    A mixture of mineralized allograft cortical and cancellous chips was used to augment the maxillary sinuses of 10 patients. Eleven sinus augmentation procedures were performed, and 19 bone cores were obtained at reentry after 6 to 7 months. Computed tomography at 6 months postaugmentation demonstrated bone formation in all sites. Light microscopic and histomorphometric evaluation confirmed bone formation at the treatment site that would receive osseointegrated implants to replace the missing maxillary posterior teeth. These encouraging results support the use of a mixture of mineralized allograft cortical and cancellous chips for sinus augmentation.

  19. Efficacy of the Survivor Health and Resilience Education (SHARE) Program to Improve Bone Health Behaviors among Adolescent Survivors of Childhood Cancer

    PubMed Central

    Mays, Darren; Black, Jessica Donze; Mosher, Revonda B.; Heinly, Allison; Shad, Aziza T.; Tercyak, Kenneth P.

    2012-01-01

    Purpose To test the efficacy of the Survivor Health and Resilience Education (SHARE) Program intervention—a manualized, behavioral intervention focusing on bone health behaviors among adolescent survivors of childhood cancer. Methods Participants were 75 teens age 11 – 21 years, 1 or more years post-treatment, currently cancer-free. Teens were randomized to a group-based intervention focusing on bone health, or a wait-list control. Bone health behaviors were assessed at baseline and 1-month post-intervention. Results Controlling for baseline outcome measures and theoretical predictors, milk consumption frequency (p = 0.03), past month calcium supplementation (p < 0.001), days in the past month with calcium supplementation (p < 0.001), and dietary calcium intake (p = 0.04) were significantly greater at 1-month follow-up among intervention participants compared with control participants. Conclusions The intervention had a significant short-term impact on self-reported bone health behaviors among adolescent survivors of childhood cancer. Research examining long-term intervention effectiveness is warranted. PMID:21328040

  20. Genetics of Bone Mass in Childhood and Adolescence: Effects of Sex and Maturation Interactions.

    PubMed

    Mitchell, Jonathan A; Chesi, Alessandra; Elci, Okan; McCormack, Shana E; Kalkwarf, Heidi J; Lappe, Joan M; Gilsanz, Vicente; Oberfield, Sharon E; Shepherd, John A; Kelly, Andrea; Zemel, Babette S; Grant, Struan F A

    2015-09-01

    We aimed to determine if adult bone mineral density (BMD) susceptibility loci were associated with pediatric bone mass and density, and if sex and pubertal stage influenced any association. We analyzed prospective areal BMD (aBMD) and bone mineral content (BMC) data from the Bone Mineral Density in Childhood Study (n = 603, European ancestry, 54% female). Linear mixed models were used to assess if 77 single-nucleotide polymorphisms (SNPs) near known adult BMD susceptibility loci interacted with sex and pubertal stage to influence the aBMD/BMC; adjusting for age, BMI, physical activity, and dietary calcium. The strongest main association was observed between an SNP near C7orf58 and distal radius aBMD. However, this association had a significant sex • SNP interaction, revealing a significant association only in females (b = -0.32, p = 1.8 × 10(-6)). Furthermore, the C12orf23 locus had significant interactions with both sex and pubertal stage, revealing associations in females during Tanner stage I for total hip aBMD (b = 0.24, p = 0.001) and femoral neck aBMD (b = 0.27, p = 3.0 × 10(-5)). In contrast, the sex • SNP interactions for loci near LRP5 and WNT16 uncovered associations that were only in males for total body less head BMC (b = 0.22, p = 4.4 × 10(-4)) and distal radius aBMD (b = 0.27, p = 0.001), respectively. Furthermore, the LRP5 locus interacted with both sex and pubertal stage, demonstrating associations that were exclusively in males during Tanner V for total hip aBMD (b = 0.29, p = 0.003). In total, significant sex • SNP interactions were found at 15 loci; pubertal stage • SNP interactions at 23 loci and 19 loci interacted with both sex and pubertal stage. In conclusion, variants originally associated with adult BMD influence bone mass in children of European ancestry, highlighting the fact that many of these loci operate early in life. However, the direction and magnitude of associations for a large number of SNPs only became evident when

  1. Unexpected cancellations in gravity theories

    SciTech Connect

    Bern, Z.; Carrasco, J. J.; Johansson, H.; Forde, D.; Ita, H.

    2008-01-15

    Recent computations of scattering amplitudes show that N=8 supergravity is surprisingly well behaved in the ultraviolet and may even be ultraviolet finite in perturbation theory. The novel cancellations necessary for ultraviolet finiteness first appear at one loop in the guise of the ''no-triangle hypothesis.'' We study one-loop amplitudes in pure Einstein gravity and point out the existence of cancellations similar to those found previously in N=8 supergravity. These cancellations go beyond those found in the one-loop effective action. Using unitarity, this suggests that generic theories of quantum gravity based on the Einstein-Hilbert action may be better behaved in the ultraviolet at higher loops than suggested by naive power counting, though without additional (supersymmetric) cancellations they diverge. We comment on future studies that should be performed to support this proposal.

  2. Unexpected Cancellations in Gravity Theories

    SciTech Connect

    Bern, Z.; Carrasco, J.J.; Forde, D.; Ita, H.; Johansson, H.; /UCLA

    2007-07-13

    Recent computations of scattering amplitudes show that N = 8 supergravity is surprisingly well behaved in the ultraviolet and may even be ultraviolet finite in perturbation theory. The novel cancellations necessary for ultraviolet finiteness first appear at one loop in the guise of the ''no-triangle hypothesis''. We study one-loop amplitudes in pure Einstein gravity and point out the existence of cancellations similar to those found previously in N = 8 supergravity. These cancellations go beyond those found in the one-loop effective action. Using unitarity, this suggests that generic theories of quantum gravity based on the Einstein-Hilbert action may be better behaved in the ultraviolet at higher loops than suggested by naive power counting, though without additional (supersymmetric) cancellations they diverge. We comment on future studies that should be performed to support this proposal.

  3. Obesity and sedentarism in children and adolescents: what should be bone?

    PubMed

    Santaliestra-Pasías, Alba M; Rey-López, Juan Pablo; Moreno Aznar, Luis A

    2013-09-01

    Paediatric overweight continues to be a public health problem, and the etiology of obesity is multifactorial and complex. Dietary patterns, physical activity (PA) and sedentary behaviors are acknowledged as major behavioural determinants of obesity. New technologies and electronic based activities have produced a decrease in PA levels, and an increase in sedentary activities in children and adolescents. Potential mechanisms that explain the association between TV viewing and childhood obesity are: displacement of PA, unhealthy food preferences produced by food advertisements, a higher energy intake by automatic eating and overconsumption caused by distraction. Interventions aimed to reduce time in sedentary behaviours are in children generally positive. However, their benefits on adiposity markers are small. Thus, if global and macro-level obesogenic factors are not changed substantially, the interventions oriented to prevent obesity will produce small benefits.

  4. The effects of bone density and crestal cortical bone thickness on micromotion and peri-implant bone strain distribution in an immediately loaded implant: a nonlinear finite element analysis

    PubMed Central

    2016-01-01

    Purpose This study investigated the effects of bone density and crestal cortical bone thickness at the implant-placement site on micromotion (relative displacement between the implant and bone) and the peri-implant bone strain distribution under immediate-loading conditions. Methods A three-dimensional finite element model of the posterior mandible with an implant was constructed. Various bone parameters were simulated, including low or high cancellous bone density, low or high crestal cortical bone density, and crestal cortical bone thicknesses ranging from 0.5 to 2.5 mm. Delayed- and immediate-loading conditions were simulated. A buccolingual oblique load of 200 N was applied to the top of the abutment. Results The maximum extent of micromotion was approximately 100 μm in the low-density cancellous bone models, whereas it was under 30 μm in the high-density cancellous bone models. Crestal cortical bone thickness significantly affected the maximum micromotion in the low-density cancellous bone models. The minimum principal strain in the peri-implant cortical bone was affected by the density of the crestal cortical bone and cancellous bone to the same degree for both delayed and immediate loading. In the low-density cancellous bone models under immediate loading, the minimum principal strain in the peri-implant cortical bone decreased with an increase in crestal cortical bone thickness. Conclusions Cancellous bone density may be a critical factor for avoiding excessive micromotion in immediately loaded implants. Crestal cortical bone thickness significantly affected the maximum extent of micromotion and peri-implant bone strain in simulations of low-density cancellous bone under immediate loading. PMID:27382504

  5. Eight months of regular in-school jumping improves indices of bone strength in adolescent boys and Girls: the POWER PE study.

    PubMed

    Weeks, Benjamin K; Young, Cath M; Beck, Belinda R

    2008-07-01

    The POWER PE study was an 8-mo, randomized, controlled, school-based exercise intervention designed to apply known principles of effective bone loading to practical opportunities to improve life-long musculoskeletal outcomes. A total of 99 adolescents (46 boys and 53 girls) with a mean age of 13.8 +/- 0.4 yr (peri- to postpubertal) volunteered to participate. Intervention subjects performed 10 min of jumping activity in place of regular physical education (PE) warm up. Control subjects performed usual PE warm-up activities. Bone mass (DXA and QUS) was assessed at baseline and follow-up along with anthropometry, maturity, muscle power, and estimates of physical activity and dietary calcium. Geometric properties (such as femoral neck [FN] moment of inertia) were calculated from DXA measures. Boys in the intervention group experienced improvements in calcaneal broadband ultrasound attenuation (BUA) (+5.0%) and fat mass (-10.5%), whereas controls did not (+1.4% and -0.8%, respectively). Girls in the intervention group improved FN BMC (+13.9%) and lumbar spine (LS) BMAD (+5.2%) more than controls (+4.9% and +1.5%, respectively). Between-group comparisons of change showed intervention effects only for whole body (WB) BMC (+10.6% versus +6.3%) for boys. Boys in the intervention group gained more lean tissue mass, trochanter (TR) BMC, LS BMC, and WB BMC and lost more fat mass than girls in the intervention group (p < 0.05). Ten minutes of jumping activity twice a week for 8 mo during adolescence seems to improve bone accrual in a sex-specific manner. Boys increased WB bone mass and BUA, and reduced fat mass, whereas girls improved bone mass at the hip and spine. PMID:18302501

  6. Cancellous bone lamellae strongly affect microcrack propagation and apparent mechanical properties: Separation of patients with osteoporotic fracture from normal controls using a 2D nonlinear finite element method (biomechanical stereology)

    PubMed Central

    Wang, Xiang; Zauel, Roger R.; Rao, D. Sudhaker; Fyhrie, David P.

    2009-01-01

    Biomechanical stereology is proposed as a two-dimensional (2D) finite element (FE) method to estimate the ability of bone tissue to sustain damage and to separate patients with osteoporotic fracture from normal controls. Briefly, 2D nonlinear compact tension FE models were created from quantitative back scattered electron images taken of iliac crest bone specimens collected from the individuals with or without osteoporotic fracture history. The effects of bone mineral microstructure on predicted bone fracture toughness and microcrack propagation were examined. The 2D FE models were used as surrogates for the real bone tissues. The calculated microcrack propagation results and bone mechanical properties were examined as surrogates for measurements from mechanical testing of actual specimens. The results for the 2D FE simulation separated patients with osteoporotic fracture from normal controls even though only the variability in tissue mineral microstructure was used to build the models. The models were deliberately created to ignore all differences in mean mineralization. Hence, the current results support the following hypotheses: (1) that material heterogeneity is important to the separation of patients with osteoporotic fracture from normal controls and; and (2) that 2D nonlinear finite element modeling can produce surrogate mechanical parameters that separate patients with fracture from normal controls. PMID:18378204

  7. Placental vitamin D receptor (VDR) expression is related to neonatal vitamin D status, placental calcium transfer, and fetal bone length in pregnant adolescents.

    PubMed

    Young, Bridget E; Cooper, Elizabeth M; McIntyre, Allison W; Kent, Tera; Witter, Frank; Harris, Z Leah; O'Brien, Kimberly O

    2014-05-01

    The purpose of the study was to identify determinants of placental vitamin D receptor (VDR) expression and placental calcium (Ca) transfer among pregnant adolescents. Placental tissue was obtained in 94 adolescents (≤18 yr) at term. In 12 of these teens, stable Ca isotopes were given intravenously ((42)Ca) and orally ((44)Ca) early in labor. Placental VDR expression was assessed via Western blot and validated by RT-PCR. Maternal-to-fetal Ca transfer was calculated as the enrichment in cord blood at delivery relative to maternal serum enrichment 2 h postdosing. Isotopic study outcomes were examined in relation to fetal long bone length, placental VDR, serum 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)2D], and parathyroid hormone (PTH) in maternal circulation and cord blood at delivery. Placental VDR expression was inversely associated with neonatal 25(OH)D (P=0.012) and positively with neonatal 1,25(OH)2D (P=0.006). Placental VDR was a positive predictor of fetal femur length Z score (P=0.018; R(2)=0.06) and was positively correlated with maternal-to-fetal transfer of intravenous (42)Ca (P=0.004; R(2)=0.62). The fetus may regulate placental VDR expression given the significant associations with neonatal vitamin D metabolites. The association between placental VDR and fetal long bone length may indicate a role for VDR in fetal bone development, potentially by mediating transplacental Ca transfer.

  8. The relationships among bone health, insulin-like growth factor-1 and sex hormones in adolescent female athletes.

    PubMed

    Gruodyte, Rita; Jürimäe, Jaak; Saar, Meeli; Jürimäe, Toivo

    2010-05-01

    The aim of this study was to determine the relationships of bone mineral density (BMD) and content (BMC) with insulin-like growth factor-1 (IGF-1), IGF-binding protein-3 (IGFBP-3) and estradiol in pubertal female athletes. The participants were 170 healthy adolescent girls (13-15 years) who participated in competitive extramural athletic programs, i.e., sports games (n = 49), track sprinting (n = 24), rhythmic gymnastics (n = 23), swimming (n = 24) and cross-country skiing (n = 17). The control group (n = 33) consisted of girls who took part only in compulsory physical education classes at school. The whole-body BMD and femoral neck and lumbar spine BMD and BMC were measured using DXA, and the volumetric BMD was calculated. Venous blood samples to determine the concentration of IGF-1, IGFBP-3 and estradiol were drawn after an overnight fasting. After adjusting for age, body height and body mass, the relationships among BMD variables, IGF-1 and the IGF-1/IGFBP-3 molar ratio remained significant only in the rhythmic gymnast group. BMDs at the femoral neck and lumbar spine were also related to estradiol levels (r = 0.45-0.60; p < 0.05) only in the rhythmic gymnast group. No relationships were found among the measured BMD, IGF axis and estradiol in other athletic groups. Only BMC at the femoral neck remained associated with the IGF-1/IGFBP-3 molar ratio in the rhythmic gymnast group after adjusting for age, body height and body mass. Stepwise multiple regression analysis indicated that IGF-1 and estradiol together explained 42.6% (R(2) x 100) of total variance in the femoral neck BMD and IGF-1 alone 35.4% (R(2) x 100) of the total variance in the femoral neck BMC only in the rhythmic gymnast group. We conclude that femoral neck and lumbar spine BMD correlated with IGF-1, IGF-1/IGFBP-3 molar ratio and estradiol in rhythmic gymnasts. No relationships were found between bone parameters and the hormones used in other athletic groups.

  9. Adolescent Diet and Subsequent Serum Hormones, Breast Density and Bone Mineral Density in Young Women: Results of the Dietary Intervention Study in Children (DISC) Follow-Up Study

    PubMed Central

    Dorgan, Joanne F.; Liu, Lea; Klifa, Catherine; Hylton, Nola; Shepherd, John A.; Stanczyk, Frank Z.; Snetselaar, Linda G.; Van Horn, Linda; Stevens, Victor J.; Robson, Alan; Kwiterovich, Peter O.; Lasser, Norman L.; Himes, John H.; Gabriel, Kelley Pettee; Kriska, Andrea; Ruder, Elizabeth H.; Fang, Carolyn Y.; Barton, Bruce A.

    2010-01-01

    Background Adolescent diet is hypothesized to influence breast cancer risk. We evaluated the long-term effects of an intervention to lower fat intake among adolescent girls on biomarkers that are related to breast cancer risk in adults. Methods A follow-up study was conducted of 230 girls who participated in the Dietary Intervention Study in Children (DISC), in which healthy, prepubertal 8-10 year olds were randomly assigned to usual care or to a behavioral intervention that promoted a reduced fat diet. Participants were 25-29 years old at follow-up visits. All tests of statistical significance are two-sided. Results In analyses that did not take account of diet at the time of the follow-up visit, the only statistically significant treatment group difference was higher bone mineral content (BMC) in intervention group participants compared to usual care group participants; their mean BMCs were 2,444g and 2,377g, respectively. After adjustment for current diet, the intervention group also had statistically significantly higher bone mineral density and luteal phase serum estradiol concentrations. Serum progesterone concentrations and breast density did not differ by treatment group in unadjusted or adjusted analyses. Conclusion Results do not support the hypothesis that consumption of a lower fat diet during adolescence reduces breast cancer risk via effects on subsequent serum estradiol and progesterone levels, breast density or BMD. Impact Additional research is needed to clarify the association of adolescent diet with breast cancer risk and to determine if the results reported here are specific to the DISC intervention or more broadly applicable. PMID:20501774

  10. Determination of mechanical properties of impacted human morsellized cancellous allografts for revision joint arthroplasty.

    PubMed

    Tanabe, Y; Wakui, T; Kobayashi, A; Ohashi, H; Kadoya, Y; Yamano, Y

    1999-12-01

    This paper deals with the characterization of mechanical properties of impacted morsellized cancellous allograft (IMCA) produced by dynamic compaction of allograft femoral heads ground by commercially available bone mills, i.e. rotating rasp and reciprocating type bone mills. Various ranges and profiles of particle size in the graft aggregates were obtained using these bone mills, and the effect of number of compaction as well as the distribution of particle sizes on the mechanical properties of IMCA under quasistatic compression and shear loading conditions was discussed. The morsellized cancellous allograft prepared by the reciprocating type bone mill showed a broad distribution of particle sizes, and gave IMCA superior mechanical properties to the graft with a more uniform size distribution, or prepared by the rotating rasp type bone mills. The increase of number of compaction also improved the mechanical properties of IMCA in compression.

  11. Body composition and bone health in long-term survivors of acute lymphoblastic leukaemia in childhood and adolescence: the protocol for a cross-sectional cohort study

    PubMed Central

    Barr, Ronald; Nayiager, Trishana; Gordon, Christopher; Marriott, Christopher; Athale, Uma

    2015-01-01

    Introduction Success in the treatment of young people with cancer, as measured conventionally by survival rates, is mitigated by late effects of therapy that impose a burden of morbidity and limit life expectancy. Among these adverse sequelae are altered body composition, especially obesity, and compromised bone health in the form of osteoporosis and increased fragility. These outcomes are potentially reversible and even preventable. This study will examine measures of body composition and bone health in long-term survivors of acute lymphoblastic leukaemia (ALL) in childhood and adolescence. These measures will be complemented by measures of physical activity and health-related quality of life (HRQL). Methods and analysis Survivors of ALL who are at least 10 years from diagnosis, following treatment on uniform protocols, will undergo measurements of body mass index; triceps skin fold thickness and mid-upper arm circumference; fat mass, lean body mass, skeletal muscle mass and bone mineral density by dual energy X-ray absorptiometry; trabecular and cortical bone indices and muscle density by peripheral quantitative CT; physical activity by the Habitual Activity Estimation Scale; and HRQL by Health Utilities Index instruments. Descriptive measures will be used for continuous variables and number (percent) for categorical variables. Associations between variables will be assessed using Fisher's exact t test and the χ2 test; correlations will be tested by the Pearson correlation coefficient. Ethics and dissemination The study is approved by the institutional research ethics board and is supported by a competitive funding award. Dissemination of the results will occur by presentations to scientific meetings and publications in peer-reviewed journals, and by posting summaries of the results on websites accessed by adolescent and young adult survivors of cancer. PMID:25603918

  12. Effects of whole-body vibration training on physical function, bone and muscle mass in adolescents and young adults with cerebral palsy

    PubMed Central

    Gusso, Silmara; Munns, Craig F; Colle, Patrícia; Derraik, José G B; Biggs, Janene B; Cutfield, Wayne S; Hofman, Paul L

    2016-01-01

    We performed a clinical trial on the effects of whole-body vibration training (WBVT) on muscle function and bone health of adolescents and young adults with cerebral palsy. Forty participants (11.3–20.8 years) with mild to moderate cerebral palsy (GMFCS II–III) underwent 20-week WBVT on a vibration plate for 9 minutes/day 4 times/week at 20 Hz (without controls). Assessments included 6-minute walk test, whole-body DXA, lower leg pQCT scans, and muscle function (force plate). Twenty weeks of WBVT were associated with increased lean mass in the total body (+770 g; p = 0.0003), trunk (+410 g; p = 0.004), and lower limbs (+240 g; p = 0.012). Bone mineral content increased in total body (+48 g; p = 0.0001), lumbar spine (+2.7 g; p = 0.0003), and lower limbs (+13 g; p < 0.0001). Similarly, bone mineral density increased in total body (+0.008 g/cm2; p = 0.013), lumbar spine (+0.014 g/cm2; p = 0.003), and lower limbs (+0.023 g/cm2; p < 0.0001). Participants reduced the time taken to perform the chair test, and improved the distance walked in the 6-minute walk test by 11% and 35% for those with GMFCS II and III, respectively. WBVT was associated with increases in muscle mass and bone mass and density, and improved mobility of adolescents and young adults with cerebral palsy. PMID:26936535

  13. 34 CFR 674.52 - Cancellation procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... accelerated— (i) May qualify for a loan cancellation for services performed before the date of acceleration; and (ii) Cannot qualify for a cancellation for services performed on or after the date of...

  14. 77 FR 19747 - Proposed Cancelation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Office of the Secretary Proposed Cancelation of the Air Taxi Authority Of VIH Cougar Helicopters, Inc... cause why it should not issue an order finding that VIH Cougar Helicopters, Inc. is not a U.S....

  15. Reexamining the Surfaces of Bone in Boys and Girls During Adolescent Growth: A 12-Year Mixed Longitudinal pQCT Study.

    PubMed

    Gabel, Leigh; Nettlefold, Lindsay; Brasher, Penelope M; Moore, Sarah A; Ahamed, Yasmin; Macdonald, Heather M; McKay, Heather A

    2015-12-01

    We revisit Stanley Garn's theory related to sex differences in endocortical and periosteal apposition during adolescence using a 12-year mixed longitudinal study design. We used peripheral quantitative computed tomography to examine bone parameters in 230 participants (110 boys, 120 girls; aged 11.0 years at baseline). We assessed total (Tt.Ar, mm(2)), cortical (Ct.Ar, mm(2)), and medullary canal area (Me.Ar, mm(2)), Ct.Ar/Tt.Ar, cortical bone mineral density (Ct.BMD, mg/cm(3)), and polar strength-strain index (SSIp , mm(3)) at the tibial midshaft (50% site). We used annual measures of height and chronological age to identify age at peak height velocity (APHV) for each participant. We compared annual accrual rates of bone parameters between boys and girls, aligned on APHV using a linear mixed effects model. At APHV, boys demonstrated greater Tt.Ar (ratio = 1.27; 95% confidence interval [CI] 1.21, 1.32), Ct.Ar (1.24 [1.18, 1.30]), Me.Ar (1.31 [1.22, 1.40]), and SSIp (1.36 [1.28, 1.45]) and less Ct.Ar/Tt.Ar (0.98 [0.96, 1.00]) and Ct.BMD (0.97 [0.96, 0.97]) compared with girls. Boys and girls demonstrated periosteal bone formation and net bone loss at the endocortical surface. Compared with girls, boys demonstrated greater annual accrual rates pre-APHV for Tt.Ar (1.18 [1.02, 1.34]) and Me.Ar (1.34 [1.11, 1.57]), lower annual accrual rates pre-APHV for Ct.Ar/Tt.Ar (0.56 [0.29, 0.83]) and Ct.BMD (-0.07 [-0.17, 0.04]), and similar annual accrual rates pre-APHV for Ct.Ar (1.10 [0.94, 1.26]) and SSIp (1.14 [0.98, 1.30]). Post-APHV, boys demonstrated similar annual accrual rates for Ct.Ar/Tt.Ar (1.01 [0.71, 1.31]) and greater annual accrual rates for all other bone parameters compared with girls (ratio = 1.23 to 2.63; 95% CI 1.11 to 3.45). Our findings support those of Garn and others of accelerated periosteal apposition during adolescence, more evident in boys than girls. However, our findings challenge the notion of greater endocortical apposition in girls, suggesting

  16. 47 CFR 213.3 - Cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Cancellation. 213.3 Section 213.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.3 Cancellation. This circular cancels: (a)...

  17. 47 CFR 213.3 - Cancellation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Cancellation. 213.3 Section 213.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.3 Cancellation. This circular cancels: (a)...

  18. 47 CFR 213.3 - Cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Cancellation. 213.3 Section 213.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.3 Cancellation. This circular cancels: (a)...

  19. 47 CFR 213.3 - Cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Cancellation. 213.3 Section 213.3 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.3 Cancellation. This circular cancels: (a)...

  20. Stress Distribution on Short Implants at Maxillary Posterior Alveolar Bone Model With Different Bone-to-Implant Contact Ratio: Finite Element Analysis.

    PubMed

    Yazicioglu, Duygu; Bayram, Burak; Oguz, Yener; Cinar, Duygu; Uckan, Sina

    2016-02-01

    The aim of this study was to evaluate the stress distribution of the short dental implants and bone-to-implant contact ratios in the posterior maxilla using 3-dimensional (3D) finite element models. Two different 3D maxillary posterior bone segments were modeled. Group 1 was composed of a bone segment consisting of cortical bone and type IV cancellous bone with 100% bone-to-implant contact. Group 2 was composed of a bone segment consisting of cortical bone and type IV cancellous bone including spherical bone design and homogenous tubular hollow spaced structures with 30% spherical porosities and 70% bone-to-implant contact ratio. Four-millimeter-diameter and 5-mm-height dental implants were assumed to be osseointegrated and placed at the center of the segments. Lateral occlusal bite force (300 N) was applied at a 25° inclination to the implants long axis. The maximum von Mises stresses in cortical and cancellous bones and implant-abutment complex were calculated. The von Mises stress values on the implants and the cancellous bone around the implants of the 70% bone-to-implant contact group were almost 3 times higher compared with the values of the 100% bone-to-implant contact group. For clinical reality, use of the 70% model for finite element analysis simulation of the posterior maxilla region better represents real alveolar bone and the increased stress and strain distributions evaluated on the cortical and cancellous bone around the dental implants.

  1. Combined with Bone Marrow-Derived Cells and rhBMP-2 for Osteonecrosis after Femoral Neck Fractures in Children and Adolescents: A case series

    PubMed Central

    Gao, Fuqiang; Sun, Wei; Guo, Wanshou; Wang, Bailiang; Cheng, Liming; Li, Zirong

    2016-01-01

    Osteonecrosis of the femoral head (ONFH) following femoral neck fractures is a rare, yet severe, disorder in children and adolescents. This study evaluated the effectiveness of core decompression (CD) combined with implantation of bone marrow–derived cells (BMDC) and rhBMP-2 for osteonecrosis of femoral head (ONFH) after femoral neck fractures in children and adolescents. This study included 51 patients, aged 11.4–18.1 years, with ARCO stages I–III ONFH after femoral neck fractures between 2004 and 2010. The hips were divided into two groups based on whether the lateral pillar of the femoral head (LPFH) was preserved: LPFH and non-LPFH groups. All patients were followed up clinically and radiographically for a minimum of 5 years. 44 patients (86.3%) had improved clinical outcome. Radiologically, 9 of the 51 hips (17.6%) exhibited collapse onset or progression of the femoral head or narrowing of the hip joint space, and one patient in the non-LPFH group required hip arthroplasty due to the worsened syndrome. The technique provided an effective therapeutic option for children and adolescents with ONFH following femoral neck fractures. It relieves hip pain and prevents the progression of osteonecrosis in young patients lasting more than 5 years after surgery. PMID:27477836

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

    NASA Technical Reports Server (NTRS)

    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.

  3. Enhanced Cancelable Biometrics for Online Signature Verification

    NASA Astrophysics Data System (ADS)

    Muramatsu, Daigo; Inuma, Manabu; Shikata, Junji; Otsuka, Akira

    Cancelable approaches for biometric person authentication have been studied to protect enrolled biometric data, and several algorithms have been proposed. One drawback of cancelable approaches is that the performance is inferior to that of non-cancelable approaches. In this paper, we propose a scheme to improve the performance of a cancelable approach for online signature verification. Our scheme generates two cancelable dataset from one raw dataset and uses them for verification. Preliminary experiments were performed using a distance-based online signature verification algorithm. The experimental results show that our proposed scheme is promising.

  4. REGULAR VERSUS DIFFUSIVE PHOTOSPHERIC FLUX CANCELLATION

    SciTech Connect

    Litvinenko, Yuri E.

    2011-04-20

    Observations of photospheric flux cancellation on the Sun imply that cancellation can be a diffusive rather than regular process. A criterion is derived, which quantifies the parameter range in which diffusive photospheric cancellation should occur. Numerical estimates show that regular cancellation models should be expected to give a quantitatively accurate description of photospheric cancellation. The estimates rely on a recently suggested scaling for a turbulent magnetic diffusivity, which is consistent with the diffusivity measurements on spatial scales varying by almost two orders of magnitude. Application of the turbulent diffusivity to large-scale dispersal of the photospheric magnetic flux is discussed.

  5. Factors that influence bone mass of healthy children and adolescents measured by quantitative ultrasound at the hand phalanges: a systematic review☆

    PubMed Central

    Krahenbühl, Tathyane; Gonçalves, Ezequiel Moreira; Costa, Eduardo Tavares; Barros, Antonio de Azevedo

    2014-01-01

    Objective: To analyze the main factors that influence bone mass in children and teenagers assessed by quantitative ultrasound (QUS) of the phalanges. Data source: A systematic literature review was performed according to the PRISMA method with searches in databases Pubmed/Medline, SciELO and Bireme for the period 2001-2012, in English and Portuguese languages, using the keywords: children, teenagers, adolescent, ultrasound finger phalanges, quantitative ultrasound of phalanges, phalangeal quantitative ultrasound. Data synthesis: 21 articles were included. Girls had, in QUS, Amplitude Dependent Speed of Sound (AD-SoS) values higher than boys during pubertal development. The values of the parameters of QUS of the phalanges and dual-energy X-ray Absorptiometry (DXA) increased with the increase of the maturational stage. Anthropometric variables such as age, weight, height, body mass index (BMI), lean mass showed positive correlations with the values of QUS of the phalanges. Physical activity has also been shown to be positively associated with increased bone mass. Factors such as ethnicity, genetics, caloric intake and socioeconomic profile have not yet shown a conclusive relationship and need a larger number of studies. Conclusions: QUS of the phalanges is a method used to evaluate the progressive acquisition of bone mass during growth and maturation of individuals in school phase, by monitoring changes that occur with increasing age and pubertal stage. There were mainly positive influences variables of sex, maturity, height, weight and BMI, with similar data when compared to the gold standard method, the DXA. PMID:25479860

  6. Behavioral evaluation of movement cancellation.

    PubMed

    Walton, Mark M G; Gandhi, Neeraj J

    2006-10-01

    The countermanding saccade task has been used in many studies to investigate the neural mechanisms that underlie the decision to execute or restrain rapid eye movements. In this task, the presentation of a saccade target is sometimes followed by the appearance of a stop cue that indicates that the subject should cancel the planned movement. Performance has been modeled as a race between motor preparation and cancellation processes. The signal that reaches its activation threshold first determines whether a saccade is generated or cancelled. In these studies, an important parameter is the time required to process the stop cue, referred to as the stop signal reaction time (SSRT). The SSRT is estimated using statistical approaches, the validity of which has not been unequivocally established. A more direct measure of this parameter might be obtainable if a method was available to "unmask" the developing motor command. This can be accomplished by air-puff-evoked blinks, which inhibit pontine omnipause neurons that serve as an inhibitory gate for the saccadic system. In the present study, brief puffs of air were used to elicit blinks at various times while rhesus monkeys performed a countermanding saccade task. If the developing motor command has not yet been cancelled, this should trigger a saccade. When blinks occurred between approximately 50 and 200 ms after target onset, saccades were often evoked. Saccades were rarely evoked more than approximately 70 ms after stop cue onset; this value represents a behavioral evaluation of SSRT and was comparable to the estimates obtained using standard statistical approaches. When saccades occurred near the SSRT on blink trials, they were often hypometric. Furthermore, Monte Carlo simulations were performed to model the effects of blink time on the race model. Overall, the study supports the validity of the statistical methods currently in use. PMID:16760340

  7. Bone quality and bone strength: benefits of the bone-forming approach.

    PubMed

    Iolascon, Giovanni; Frizzi, Laura; Di Pietro, Gioconda; Capaldo, Annarita; Luciano, Fabrizio; Gimigliano, Francesca

    2014-01-01

    The ability of bone to resist fracture depends on the intrinsic properties of the materials that comprise the bone matrix mineralization, the amount of bone (i.e. mass), and the spatial distribution of the bone mass (i.e. microarchitecture). Antiresorptive agents may prevent the decay of cancellous bone and cortical thinning, with no improvement of bone microstructure, leading to a partial correction of the principal bone quality defect in osteoporosis, the disruption of trabecular microarchitecture. Anabolic agents promote bone formation at both trabecular and endocortical surfaces, resulting in an increase of cancellous bone volume and cortical thickness. The improvement of cortical bone strength may be limited by an increase in cortical porosity. strontium ranelate improves trabecular network and cortical thickness that will contribute to anti-fracture efficacy at both vertebral and non-vertebral sites. The results of clinical and experimental studies are consistent with the mode of action of strontium involving dissociation between bone formation and resorption leading to a stimulation both trabecular and cortical bone formation without increasing cortical porosity. PMID:25002875

  8. Bone cysts: unicameral and aneurysmal bone cyst.

    PubMed

    Mascard, E; Gomez-Brouchet, A; Lambot, K

    2015-02-01

    Simple and aneurysmal bone cysts are benign lytic bone lesions, usually encountered in children and adolescents. Simple bone cyst is a cystic, fluid-filled lesion, which may be unicameral (UBC) or partially separated. UBC can involve all bones, but usually the long bone metaphysis and otherwise primarily the proximal humerus and proximal femur. The classic aneurysmal bone cyst (ABC) is an expansive and hemorrhagic tumor, usually showing characteristic translocation. About 30% of ABCs are secondary, without translocation; they occur in reaction to another, usually benign, bone lesion. ABCs are metaphyseal, excentric, bulging, fluid-filled and multicameral, and may develop in all bones of the skeleton. On MRI, the fluid level is evocative. It is mandatory to distinguish ABC from UBC, as prognosis and treatment are different. UBCs resolve spontaneously between adolescence and adulthood; the main concern is the risk of pathologic fracture. Treatment in non-threatening forms consists in intracystic injection of methylprednisolone. When there is a risk of fracture, especially of the femoral neck, surgery with curettage, filling with bone substitute or graft and osteosynthesis may be required. ABCs are potentially more aggressive, with a risk of bone destruction. Diagnosis must systematically be confirmed by biopsy, identifying soft-tissue parts, as telangiectatic sarcoma can mimic ABC. Intra-lesional sclerotherapy with alcohol is an effective treatment. In spinal ABC and in aggressive lesions with a risk of fracture, surgical treatment should be preferred, possibly after preoperative embolization. The risk of malignant transformation is very low, except in case of radiation therapy.

  9. 34 CFR 674.59 - Cancellation for military service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 3 2014-07-01 2014-07-01 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... fraction of a year beyond a complete year of service, does not qualify for military cancellation....

  10. 34 CFR 674.59 - Cancellation for military service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 3 2012-07-01 2012-07-01 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... fraction of a year beyond a complete year of service, does not qualify for military cancellation....

  11. 34 CFR 674.59 - Cancellation for military service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 3 2013-07-01 2013-07-01 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... fraction of a year beyond a complete year of service, does not qualify for military cancellation....

  12. Onlay Bone Grafts in Head and Neck Reconstruction

    PubMed Central

    Yazar, Sukru

    2010-01-01

    Bone grafts are used in a variety of clinical situations and can be divided into two categories: treatment of bone gaps (inlay bone grafting) and bone projection (onlay bone grafting). Cortical grafts are useful in situations requiring immediate mechanical strength. These grafts can survive with or without complete revascularization or resorption and are primarily used by plastic surgeons in the treatment of bone volume deficiency. Cancellous grafts, in contrast, have no mechanical strength and therefore require additional support to bridge bone defects. Thus, they are used primarily for the treatment of bone gaps and in general revascularize quickly, resorb completely, and stimulate significant new bone formation. PMID:22550447

  13. 29 CFR 4.190 - Contract cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., the contract is subject upon written notice to cancellation by the contracting agency, whereupon the... contract is similarly subject upon written notice to immediate cancellation by the contracting agency and... in paragraph (a). Such contract is without warrant of law and has no force and effect and is void...

  14. 25 CFR 214.19 - Cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Cancellation. 214.19 Section 214.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.19 Cancellation. When a lessee makes application for...

  15. 25 CFR 213.40 - Cancellations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Cancellations. 213.40 Section 213.40 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF RESTRICTED LANDS OF MEMBERS OF FIVE CIVILIZED TRIBES, OKLAHOMA, FOR MINING Operations § 213.40 Cancellations. (a) When, in the...

  16. 25 CFR 214.19 - Cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Cancellation. 214.19 Section 214.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.19 Cancellation. When a lessee makes application for...

  17. 25 CFR 213.40 - Cancellations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Cancellations. 213.40 Section 213.40 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF RESTRICTED LANDS OF MEMBERS OF FIVE CIVILIZED TRIBES, OKLAHOMA, FOR MINING Operations § 213.40 Cancellations. (a) When, in the...

  18. 25 CFR 213.40 - Cancellations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Cancellations. 213.40 Section 213.40 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF RESTRICTED LANDS OF MEMBERS OF FIVE CIVILIZED TRIBES, OKLAHOMA, FOR MINING Operations § 213.40 Cancellations. (a) When, in the...

  19. 25 CFR 214.19 - Cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Cancellation. 214.19 Section 214.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.19 Cancellation. When a lessee makes application for...

  20. 25 CFR 214.19 - Cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Cancellation. 214.19 Section 214.19 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.19 Cancellation. When a lessee makes application for...

  1. 25 CFR 227.28 - Cancellations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Cancellations. 227.28 Section 227.28 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF CERTAIN LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING Operations § 227.28 Cancellations. Leases shall...

  2. 25 CFR 227.28 - Cancellations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Cancellations. 227.28 Section 227.28 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF CERTAIN LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING Operations § 227.28 Cancellations. Leases shall...

  3. 25 CFR 227.28 - Cancellations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Cancellations. 227.28 Section 227.28 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF CERTAIN LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING Operations § 227.28 Cancellations. Leases shall...

  4. 25 CFR 227.28 - Cancellations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Cancellations. 227.28 Section 227.28 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF CERTAIN LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING Operations § 227.28 Cancellations. Leases shall...

  5. 25 CFR 227.28 - Cancellations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Cancellations. 227.28 Section 227.28 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF CERTAIN LANDS IN WIND RIVER INDIAN RESERVATION, WYOMING, FOR OIL AND GAS MINING Operations § 227.28 Cancellations. Leases shall...

  6. 34 CFR 674.52 - Cancellation procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... borrower's loan deferment under § 674.34(c) to run concurrently with any period for which cancellation... run concurrently with any period for which a cancellation under §§ 674.53, 674.56, 674.57, or 674.58 is granted. (e) National community service. No borrower who has received a benefit under subtitle...

  7. 25 CFR 23.53 - Cancellation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Cancellation. 23.53 Section 23.53 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR HUMAN SERVICES INDIAN CHILD WELFARE ACT General and Uniform Grant Administration Provisions and Requirements § 23.53 Cancellation. (a) The grants officer may...

  8. 43 CFR 3601.62 - Cancellation procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Disposal; General Provisions Contract and Permit Cancellation § 3601.62 Cancellation procedure. (a... notice under paragraph (a) of this section, or if delivery of the notice is refused, or not completed...

  9. 36 CFR 223.116 - Cancellation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER Timber Sale Contracts Contract Administration § 223.116 Cancellation. (a) Timber sale contracts and permits may be canceled: (1) For serious or continued violation of... the value of the timber remaining to be cut is diminished materially because of catastrophic...

  10. 7 CFR 1942.12 - Loan cancellation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS (CONTINUED) ASSOCIATIONS Community Facility Loans § 1942.12 Loan cancellation. Loans which have... Development Manager or State Director may prepare and execute Form Rural Development 1940-10, Cancellation of... disbursement has been received or is subsequently received in the Area Office, the Rural Development...

  11. 34 CFR 674.52 - Cancellation procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... covered under the Family and Medical Leave Act of 1993 (FMLA) (29 U.S.C. 2601, et seq.), the borrower... cancellation based on a claim of simultaneous employment as a nurse or medical technician in two or more... of title I of the National and Community Service Act of 1990 may receive a cancellation under......

  12. 43 CFR 3601.62 - Cancellation procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL MATERIALS DISPOSAL Mineral Materials Disposal; General Provisions Contract and Permit Cancellation § 3601.62 Cancellation procedure. (a... notice under paragraph (a) of this section, or if delivery of the notice is refused, or not completed...

  13. 44 CFR 206.376 - Loan cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Community Disaster Loans § 206.376 Loan cancellation. (a) FEMA shall cancel repayment of all or part of a Special Community Disaster Loan to the extent... Special Community Disaster loans issued from the dates of enactment of Public Law 109-88 and Public...

  14. 44 CFR 206.376 - Loan cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Community Disaster Loans § 206.376 Loan cancellation. (a) FEMA shall cancel repayment of all or part of a Special Community Disaster Loan to the extent... Special Community Disaster loans issued from the dates of enactment of Public Law 109-88 and Public...

  15. 44 CFR 206.366 - Loan cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Community Disaster Loans § 206.366 Loan cancellation. (a) Policies. (1) FEMA shall cancel repayment of all or part of a Community Disaster Loan to the... incurred for general government purposes, such as police and fire protection, trash collection,...

  16. 44 CFR 206.366 - Loan cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Community Disaster Loans § 206.366 Loan cancellation. (a) Policies. (1) FEMA shall cancel repayment of all or part of a Community Disaster Loan to the... incurred for general government purposes, such as police and fire protection, trash collection,...

  17. 44 CFR 206.376 - Loan cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Community Disaster Loans § 206.376 Loan cancellation. (a) FEMA shall cancel repayment of all or part of a Special Community Disaster Loan to the extent... Special Community Disaster loans issued from the dates of enactment of Public Law 109-88 and Public...

  18. 44 CFR 206.366 - Loan cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Community Disaster Loans § 206.366 Loan cancellation. (a) Policies. (1) FEMA shall cancel repayment of all or part of a Community Disaster Loan to the... incurred for general government purposes, such as police and fire protection, trash collection,...

  19. 44 CFR 206.366 - Loan cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Community Disaster Loans § 206.366 Loan cancellation. (a) Policies. (1) FEMA shall cancel repayment of all or part of a Community Disaster Loan to the... incurred for general government purposes, such as police and fire protection, trash collection,...

  20. Noise canceling in-situ detection

    SciTech Connect

    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.

  1. 7 CFR 1956.70 - Cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS (CONTINUED) DEBT SETTLEMENT Debt Settlement-Farm Loan Programs and Multi-Family Housing § 1956.70 Cancellation. Nonjudgment debts may be canceled in the following instances: (a) With application. The debt or any extension thereof on Farmer Programs debts do not have to be due and payable under the terms...

  2. Nuclear plant cancellations: causes, costs, and consequences

    SciTech Connect

    Not Available

    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.

  3. 78 FR 48456 - Notice of Cancellation of Customs Broker Licenses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ... permits of certain customs brokers are being cancelled without prejudice. SUPPLEMENTARY INFORMATION... following customs broker licenses are cancelled without prejudice. ] Last/company name First name License...

  4. Brillouin scattering self-cancellation.

    PubMed

    Florez, O; Jarschel, P F; Espinel, Y A V; Cordeiro, C M B; Mayer Alegre, T P; Wiederhecker, G S; Dainese, P

    2016-01-01

    The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin scattering arising from Rayleigh acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it. PMID:27283092

  5. Brillouin scattering self-cancellation

    NASA Astrophysics Data System (ADS)

    Florez, O.; Jarschel, P. F.; Espinel, Y. A. V.; Cordeiro, C. M. B.; Mayer Alegre, T. P.; Wiederhecker, G. S.; Dainese, P.

    2016-06-01

    The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin scattering arising from Rayleigh acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon-phonon interaction, enhancing or suppressing it.

  6. Brillouin scattering self-cancellation

    PubMed Central

    Florez, O.; Jarschel, P. F.; Espinel, Y. A. V.; Cordeiro, C. M. B.; Mayer Alegre, T. P.; Wiederhecker, G. S.; Dainese, P.

    2016-01-01

    The interaction between light and acoustic phonons is strongly modified in sub-wavelength confinement, and has led to the demonstration and control of Brillouin scattering in photonic structures such as nano-scale optical waveguides and cavities. Besides the small optical mode volume, two physical mechanisms come into play simultaneously: a volume effect caused by the strain-induced refractive index perturbation (known as photo-elasticity), and a surface effect caused by the shift of the optical boundaries due to mechanical vibrations. As a result, proper material and structure engineering allows one to control each contribution individually. Here, we experimentally demonstrate the perfect cancellation of Brillouin scattering arising from Rayleigh acoustic waves by engineering a silica nanowire with exactly opposing photo-elastic and moving-boundary effects. This demonstration provides clear experimental evidence that the interplay between the two mechanisms is a promising tool to precisely control the photon–phonon interaction, enhancing or suppressing it. PMID:27283092

  7. Background canceling surface alpha detector

    DOEpatents

    MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

    1996-01-01

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

  8. Background canceling surface alpha detector

    DOEpatents

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

    1996-06-11

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

  9. Muscle torque relative to cross-sectional area and the functional muscle-bone unit in children and adolescents with chronic disease.

    PubMed

    Lee, Dale Y; Wetzsteon, Rachel J; Zemel, Babette S; Shults, Justine; Organ, Jason M; Foster, Bethany J; Herskovitz, Rita M; Foerster, Debbie L; Leonard, Mary B

    2015-03-01

    Measures of muscle mass or size are often used as surrogates of forces acting on bone. However, chronic diseases may be associated with abnormal muscle force relative to muscle size. The muscle-bone unit was examined in 64 children and adolescents with new-onset Crohn's disease (CD), 54 with chronic kidney disease (CKD), 51 treated with glucocorticoids for nephrotic syndrome (NS), and 264 healthy controls. Muscle torque was assessed by isometric ankle dynamometry. Calf muscle cross-sectional area (CSA) and tibia cortical section modulus (Zp) were assessed by quantitative CT. Log-linear regression was used to determine the relations among muscle CSA, muscle torque, and Zp, adjusted for tibia length, age, Tanner stage, sex, and race. Muscle CSA and muscle torque-relative-to-muscle CSA were significantly lower than controls in advanced CKD (CSA -8.7%, p = 0.01; torque -22.9%, p < 0.001) and moderate-to-severe CD (CSA -14.1%, p < 0.001; torque -7.6%, p = 0.05), but not in NS. Zp was 11.5% lower in advanced CKD (p = 0.005) compared to controls, and this deficit was attenuated to 6.7% (p = 0.05) with adjustment for muscle CSA. With additional adjustment for muscle torque and body weight, Zp was 5.9% lower and the difference with controls was no longer significant (p = 0.09). In participants with moderate-to-severe CD, Zp was 6.8% greater than predicted (p = 0.01) given muscle CSA and torque deficits (R(2)  = 0.92), likely due to acute muscle loss in newly-diagnosed patients. Zp did not differ in NS, compared with controls. In conclusion, muscle torque relative to muscle CSA was significantly lower in CKD and CD, compared with controls, and was independently associated with Zp. Future studies are needed to determine if abnormal muscle strength contributes to progressive bone deficits in chronic disease, independent of muscle area. © 2014 American Society for Bone and Mineral Research. PMID:25264231

  10. Mechanical loading with or without weight-bearing activity: influence on bone strength index in elite female adolescent athletes engaged in water polo, gymnastics, and track-and-field.

    PubMed

    Greene, David A; Naughton, Geraldine A; Bradshaw, Elizabeth; Moresi, Mark; Ducher, Gaele

    2012-09-01

    Bone health is considered not to benefit from water-based sports because of their weight-supported nature, but available evidence primarily relies on DXA technology. Our purpose was to investigate musculoskeletal health in the upper and lower body in well-trained adolescent female athletes using pQCT and compare these athletes with less-active, age- and sex-matched peers. Bone mineral content, volumetric cortical and trabecular BMD, total and cortical area, and bone strength index were assessed at the distal and proximal tibia and radius in four groups of adolescent females (mean age, 14.9 years) including water polo players (n = 30), gymnasts (n = 25), track-and-field athletes (n = 34), and nonactive controls (n = 28). Water polo players did not show any benefit in bone strength index or muscle size in the lower leg when compared with controls. In contrast, gymnasts showed 60.1 % and 53.4 % greater bone strength index at the distal and proximal tibia, respectively, than nonactive females (p < 0.05). Similarly, track-and-field athletes displayed 33.9 % and 14.7 % greater bone strength index at the distal and proximal tibia, respectively, compared with controls (p < 0.05). In the upper body, water polo players had 31.9 % greater bone strength index at the distal radius, but not the radial shaft, and 15.2 % larger forearm muscle cross-sectional area than controls (p < 0.05). The greatest musculoskeletal benefits in the upper body were found in gymnasts. In conclusion, despite training at an elite level, female water polo players did not show any benefits in musculoskeletal health in the lower leg and only limited benefits in the upper body when compared with nonactive girls. PMID:22614913

  11. Mechanical loading with or without weight-bearing activity: influence on bone strength index in elite female adolescent athletes engaged in water polo, gymnastics, and track-and-field.

    PubMed

    Greene, David A; Naughton, Geraldine A; Bradshaw, Elizabeth; Moresi, Mark; Ducher, Gaele

    2012-09-01

    Bone health is considered not to benefit from water-based sports because of their weight-supported nature, but available evidence primarily relies on DXA technology. Our purpose was to investigate musculoskeletal health in the upper and lower body in well-trained adolescent female athletes using pQCT and compare these athletes with less-active, age- and sex-matched peers. Bone mineral content, volumetric cortical and trabecular BMD, total and cortical area, and bone strength index were assessed at the distal and proximal tibia and radius in four groups of adolescent females (mean age, 14.9 years) including water polo players (n = 30), gymnasts (n = 25), track-and-field athletes (n = 34), and nonactive controls (n = 28). Water polo players did not show any benefit in bone strength index or muscle size in the lower leg when compared with controls. In contrast, gymnasts showed 60.1 % and 53.4 % greater bone strength index at the distal and proximal tibia, respectively, than nonactive females (p < 0.05). Similarly, track-and-field athletes displayed 33.9 % and 14.7 % greater bone strength index at the distal and proximal tibia, respectively, compared with controls (p < 0.05). In the upper body, water polo players had 31.9 % greater bone strength index at the distal radius, but not the radial shaft, and 15.2 % larger forearm muscle cross-sectional area than controls (p < 0.05). The greatest musculoskeletal benefits in the upper body were found in gymnasts. In conclusion, despite training at an elite level, female water polo players did not show any benefits in musculoskeletal health in the lower leg and only limited benefits in the upper body when compared with nonactive girls.

  12. Prostaglandin E2 Prevents Bone Loss and Adds Extra Bone to Immobilized Distal Femoral Metaphysis in Female Rats

    NASA Technical Reports Server (NTRS)

    Akamine, T.; Jee, W. S. S.; Ke, H. Z.; Li, X. J.; Lin, B. Y.

    1992-01-01

    The object of this study was to determine whether prostaglandin E2 (PGE2) can prevent disuse (underloading)-induced cancellous bone loss. Thirteen-month-old retired female Sprague-Dawley breeders served as controls or were subjected to right hindlimb immobilization by bandaging and simultaneously treated subcutaneously daily with 0, 1, 3, or 6 mg PGE2/kg/d for two and six weeks. Histomorphometric analyses were performed on the cancellous bone using double-fluorescent labeled, 20 micron thick, undecalcified distal femoral metaphysis sections. We found that PGE2 administration not only prevented disuse-induced bone loss, but also added extra bone to disuse cancellous bone in a dose-response manner. PGE2 prevented the disuse-induced osteopenia by stimulating more bone formation than and shortening the period of bone remodeling. It activated woven bone formation, stimulated lamellar bone formation, and increased the eroded bone surface above that caused by disuse alone. While underloading increased the remodeling period (sigma), PGE2 treatment of underloaded bone shortened the time for osteoclastic bone resorption and bone remodeling, and thus reduced the remodeling space. The study shows that PGE2 is a powerful anabolic agent that prevents disuse-induced osteopenia and adds extra bone to these same bones.

  13. [The results of resonance frequency analysis by dental implantation after bone augmentation for alveolar bone atrophy].

    PubMed

    Kulakov, A A; Braĭlovskaia, T V; Osman, B M; Bedretdinov, R M; Dzhakoniia, V D

    2014-01-01

    The report concerns dental implantation effectiveness in case of jawbone atrophy. Thirty patients were included in the study to reveal resonance frequency analysis rates of intraosseous dental implants by dental implant placement with bone augmentation using the veneer technique of cortico-cancellous blocks and guided bone regeneration (GBR) with biodegradable membranes and pins having poly (dl- lactic acid) base.

  14. Leisure time computer use and adolescent bone health—findings from the Tromsø Study, Fit Futures: a cross-sectional study

    PubMed Central

    Winther, Anne; Ahmed, Luai Awad; Furberg, Anne-Sofie; Grimnes, Guri; Jorde, Rolf; Nilsen, Ole Andreas; Dennison, Elaine; Emaus, Nina

    2015-01-01

    Objectives Low levels of physical activity may have considerable negative effects on bone health in adolescence, and increasing screen time in place of sporting activity during growth is worrying. This study explored the associations between self-reported screen time at weekends and bone mineral density (BMD). Design In 2010/2011, 1038 (93%) of the region’s first-year upper-secondary school students (15–18 years) attended the Tromsø Study, Fit Futures 1 (FF1). A follow-up survey (FF2) took place in 2012/2013. BMD at total hip, femoral neck and total body was measured as g/cm² by dual X-ray absorptiometry (GE Lunar prodigy). Lifestyle variables were self-reported, including questions on hours per day spent in front of television/computer during weekends and hours spent on leisure time physical activities. Complete data sets for 388/312 girls and 359/231 boys at FF1/FF2, respectively, were used in analyses. Sex stratified multiple regression analyses were performed. Results Many adolescents balanced 2–4 h screen time with moderate or high physical activity levels. Screen time was positively related to body mass index (BMI) in boys (p=0.002), who spent more time in front of the computer than girls did (p<0.001). In boys, screen time was adversely associated with BMDFF1 at all sites, and these associations remained robust to adjustments for age, puberty, height, BMI, physical activity, vitamin D levels, smoking, alcohol, calcium and carbonated drink consumption (p<0.05). Screen time was also negatively associated with total hip BMDFF2 (p=0.031). In contrast, girls who spent 4–6 h in front of the computer had higher BMD than the reference (<2 h). Conclusions In Norwegian boys, time spent on screen-based sedentary activity was negatively associated with BMD levels; this relationship persisted 2 years later. Such negative associations were not present among girls. Whether this surprising result is explained by biological differences remains unclear

  15. Magnetic Flux Cancellation and Formation of Prominence

    NASA Astrophysics Data System (ADS)

    Miley, George; Kim, Mun Song; Chon Nam, Sok; Kim, Kyong Chol

    2015-08-01

    Magnetic flux cancellation appears to be closely related to various kinds of solar activities such as flares, microflares/surges/jets, X-ray bright points, erupting mini-filaments, transition region explosive events, filament formation, filament activation and eruption, and coronal mass ejections. It is commonly believed that magnetic reconnections in the low atmosphere are responsible for canceling magnetic features, and magnetic fragments are observed to originate as bipoles. According to the Sweet-Parker type reconnection model, the inflow speed closely corresponds to the converging speed of each pole in a canceling magnetic feature and the rate of flux cancellation must be explained by the observed converging speed. As distinct from the corona, the efficiency of photospheric magnetic reconnection may be due to the small Cowling conductivity, instead of the Spitzer, of weakly ionized and magnetized plasma in the low atmosphere of the sun. Using the VAL-C atmospheric model and Cowling conductivity, we have computed the parameters describing Sweet-Parker type reconnecting current sheets in the plasma of the solar photosphere and chromosphere, and particularly for the phenomena of magnetic flux cancellation and dark filament formation which occurred on July 2, 1994 we have estimated the rate of flux cancellation, the inflow speed(the converging speed) and the upward mass flux to compare with the observation. The results show that when taking account of the Cowling conductivity in the low atmosphere, large flux cancellation rates(>1019Mxhr-1) in solar active regions are better explained than by the Spitzer conductivity-considered reconnection model. Particularly for the flux cancellation event on July 2, 1994, the inflow speed(0.26kms-1)is almost similar to the converging speed(0.22kms-1)and the upward mass flux(3.3X1012gs-1) in the model is sufficient for the large dark filament formation in a time of several hours through magnetic flux cancellation process.

  16. Estrogen regulates the rate of bone turnover but bone balance in ovariectomized rats is modulated by prevailing mechanical strain

    NASA Technical Reports Server (NTRS)

    Westerlind, K. C.; Wronski, T. J.; Ritman, E. L.; Luo, Z. P.; An, K. N.; Bell, N. H.; Turner, R. T.

    1997-01-01

    Estrogen deficiency induced bone loss is associated with increased bone turnover in rats and humans. The respective roles of increased bone turnover and altered balance between bone formation and bone resorption in mediating estrogen deficiency-induced cancellous bone loss was investigated in ovariectomized rats. Ovariectomy resulted in increased bone turnover in the distal femur. However, cancellous bone was preferentially lost in the metaphysis, a site that normally experiences low strain energy. No bone loss was observed in the epiphysis, a site experiencing higher strain energy. The role of mechanical strain in maintaining bone balance was investigated by altering the strain history. Mechanical strain was increased and decreased in long bones of ovariectomized rats by treadmill exercise and functional unloading, respectively. Functional unloading was achieved during orbital spaceflight and following unilateral sciatic neurotomy. Increasing mechanical loading reduced bone loss in the metaphysis. In contrast, decreasing loading accentuated bone loss in the metaphysis and resulted in bone loss in the epiphysis. Finally, administration of estrogen to ovariectomized rats reduced bone loss in the unloaded and prevented loss in the loaded limb following unilateral sciatic neurotomy in part by reducing indices of bone turnover. These results suggest that estrogen regulates the rate of bone turnover, but the overall balance between bone formation and bone resorption is influenced by prevailing levels of mechanical strain.

  17. Estrogen regulates the rate of bone turnover but bone balance in ovariectomized rats is modulated by prevailing mechanical strain

    PubMed Central

    Westerlind, Kim C.; Wronski, Thomas J.; Ritman, Erik L.; Luo, Zong-Ping; An, Kai-Nan; Bell, Norman H.; Turner, Russell T.

    1997-01-01

    Estrogen deficiency induced bone loss is associated with increased bone turnover in rats and humans. The respective roles of increased bone turnover and altered balance between bone formation and bone resorption in mediating estrogen deficiency-induced cancellous bone loss was investigated in ovariectomized rats. Ovariectomy resulted in increased bone turnover in the distal femur. However, cancellous bone was preferentially lost in the metaphysis, a site that normally experiences low strain energy. No bone loss was observed in the epiphysis, a site experiencing higher strain energy. The role of mechanical strain in maintaining bone balance was investigated by altering the strain history. Mechanical strain was increased and decreased in long bones of ovariectomized rats by treadmill exercise and functional unloading, respectively. Functional unloading was achieved during orbital spaceflight and following unilateral sciatic neurotomy. Increasing mechanical loading reduced bone loss in the metaphysis. In contrast, decreasing loading accentuated bone loss in the metaphysis and resulted in bone loss in the epiphysis. Finally, administration of estrogen to ovariectomized rats reduced bone loss in the unloaded and prevented loss in the loaded limb following unilateral sciatic neurotomy in part by reducing indices of bone turnover. These results suggest that estrogen regulates the rate of bone turnover, but the overall balance between bone formation and bone resorption is influenced by prevailing levels of mechanical strain. PMID:9108129

  18. Low-Power Ultrasounds as a Tool to Culture Human Osteoblasts inside Cancellous Hydroxyapatite

    PubMed Central

    Fassina, Lorenzo; Saino, Enrica; Cusella De Angelis, Maria Gabriella; Magenes, Giovanni; Benazzo, Francesco; Visai, Livia

    2010-01-01

    Bone graft substitutes and cancellous biomaterials have been widely used to heal critical-size long bone defects due to trauma, tumor resection, and tissue degeneration. In particular, porous hydroxyapatite is widely used in reconstructive bone surgery owing to its biocompatibility. In addition, the in vitro modification of cancellous hydroxyapatite with osteogenic signals enhances the tissue regeneration in vivo, suggesting that the biomaterial modification could play an important role in tissue engineering. In this study, we have followed a tissue-engineering strategy where ultrasonically stimulated SAOS-2 human osteoblasts proliferated and built their extracellular matrix inside a porous hydroxyapatite scaffold. The ultrasonic stimulus had the following parameters: average power equal to 149 mW and frequency of 1.5 MHz. In comparison with control conditions, the ultrasonic stimulus increased the cell proliferation and the surface coating with bone proteins (decorin, osteocalcin, osteopontin, type-I collagen, and type-III collagen). The mechanical stimulus aimed at obtaining a better modification of the biomaterial internal surface in terms of cell colonization and coating with bone matrix. The modified biomaterial could be used, in clinical applications, as an implant for bone repair. PMID:20379359

  19. 42 CFR 493.1842 - Cancellation of Medicare approval.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Written notice of the rationale for, effective date, and effect of, cancellation; (2) Opportunity to submit written evidence or other information against cancellation of the laboratory's approval. This... appeals procedures set forth in § 493.1844. (c) Effect of cancellation. Cancellation of Medicare...

  20. 43 CFR 3452.2-1 - Cause for cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Cause for cancellation. 3452.2-1 Section... Relinquishment, Cancellation, and Termination § 3452.2-1 Cause for cancellation. (a) The authorized officer... continued operation requirements shall be subject to cancellation in whole or in part. In deciding...

  1. 43 CFR 3452.2-1 - Cause for cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Cause for cancellation. 3452.2-1 Section... Relinquishment, Cancellation, and Termination § 3452.2-1 Cause for cancellation. (a) The authorized officer... continued operation requirements shall be subject to cancellation in whole or in part. In deciding...

  2. 43 CFR 3452.2-1 - Cause for cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Cause for cancellation. 3452.2-1 Section... Relinquishment, Cancellation, and Termination § 3452.2-1 Cause for cancellation. (a) The authorized officer... continued operation requirements shall be subject to cancellation in whole or in part. In deciding...

  3. 43 CFR 3452.2-1 - Cause for cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Cause for cancellation. 3452.2-1 Section... Relinquishment, Cancellation, and Termination § 3452.2-1 Cause for cancellation. (a) The authorized officer... continued operation requirements shall be subject to cancellation in whole or in part. In deciding...

  4. 18 CFR 4.83 - Cancellation and loss of priority.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... opportunity for hearing. Cancellation of a permit will result in loss of the permittee's priority of... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Cancellation and loss... Permit § 4.83 Cancellation and loss of priority. (a) The Commission may cancel a preliminary permit...

  5. 18 CFR 4.83 - Cancellation and loss of priority.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... opportunity for hearing. Cancellation of a permit will result in loss of the permittee's priority of... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Cancellation and loss... Permit § 4.83 Cancellation and loss of priority. (a) The Commission may cancel a preliminary permit...

  6. 12 CFR 209.3 - Cancellation of Reserve Bank stock.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Cancellation of Reserve Bank stock. 209.3... ISSUE AND CANCELLATION OF FEDERAL RESERVE BANK CAPITAL STOCK (REGULATION I) § 209.3 Cancellation of Reserve Bank stock. (a) Application for cancellation. Any bank that desires to withdraw from membership...

  7. 34 CFR 674.59 - Cancellation for military service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... balance on an NDSL or Perkins loan for active duty service that ended before August 14, 2008, as a member... 34 Education 3 2011-07-01 2011-07-01 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...

  8. 42 CFR 493.1842 - Cancellation of Medicare approval.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false Cancellation of Medicare approval. 493.1842 Section 493.1842 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... Cancellation of Medicare approval. (a) Basis for cancellation. (1) CMS always cancels a laboratory's...

  9. 18 CFR 4.83 - Cancellation and loss of priority.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Cancellation and loss... Permit § 4.83 Cancellation and loss of priority. (a) The Commission may cancel a preliminary permit after... opportunity for hearing. Cancellation of a permit will result in loss of the permittee's priority...

  10. 18 CFR 4.83 - Cancellation and loss of priority.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Cancellation and loss... Permit § 4.83 Cancellation and loss of priority. (a) The Commission may cancel a preliminary permit after... opportunity for hearing. Cancellation of a permit will result in loss of the permittee's priority...

  11. 18 CFR 4.83 - Cancellation and loss of priority.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Cancellation and loss... Permit § 4.83 Cancellation and loss of priority. (a) The Commission may cancel a preliminary permit after... opportunity for hearing. Cancellation of a permit will result in loss of the permittee's priority...

  12. Muscle Torque Relative to Cross-Sectional Area and the Functional Muscle-Bone Unit in Children and Adolescents with Chronic Disease

    PubMed Central

    Lee, Dale Y.; Wetzsteon, Rachel J.; Zemel, Babette S.; Shults, Justine; Organ, Jason M.; Foster, Bethany J.; Herskovitz, Rita M.; Foerster, Debbie L.; Leonard, Mary B.

    2015-01-01

    Measures of muscle mass or size are often used as surrogates of forces acting on bone. However, chronic diseases may be associated with abnormal muscle force relative to muscle size. The muscle-bone unit was examined in 64 children and adolescents with new-onset Crohn’s disease (CD), 54 with chronic kidney disease (CKD), 51 treated with glucocorticoids for nephrotic syndrome (NS), and 264 healthy controls. Muscle torque was assessed by isometric ankle dynamometry. Calf muscle cross-sectional area (CSA) and tibia cortical section modulus (Zp) were assessed by quantitative CT. Log-linear regression was used to determine the relations among muscle CSA, muscle torque, and Zp, adjusted for tibia length, age, Tanner stage, sex, and race. Muscle CSA and muscle torque-relative-to-muscle CSA were significantly lower than controls in advanced CKD (CSA −8.7%, p = 0.01; torque −22.9%, p < 0.001) and moderate-to-severe CD (CSA −14.1%, p < 0.001; torque −7.6%, p = 0.05), but not in NS. Zp was 11.5% lower in advanced CKD (p = 0.005) compared to controls, and this deficit was attenuated to 6.7% (p = 0.05) with adjustment for muscle CSA. With additional adjustment for muscle torque and body weight, Zp was 5.9% lower and the difference with controls was no longer significant (p = 0.09). In participants with moderate-to-severe CD, Zp was 6.8% greater than predicted (p = 0.01) given muscle CSA and torque deficits (R2=0.92), likely due to acute muscle loss in newly diagnosed patients. Zp did not differ in NS, compared with controls. In conclusion, muscle torque relative to muscle CSA was significantly lower in CKD and CD, compared with controls, and was independently associated with Zp. Future studies are needed to determine if abnormal muscle strength contributes to progressive bone deficits in chronic disease, independent of muscle area. PMID:25264231

  13. Effective Topological Charge Cancelation Mechanism

    PubMed Central

    Mesarec, Luka; Góźdź, Wojciech; Iglič, Aleš; Kralj, Samo

    2016-01-01

    Topological defects (TDs) appear almost unavoidably in continuous symmetry breaking phase transitions. The topological origin makes their key features independent of systems’ microscopic details; therefore TDs display many universalities. Because of their strong impact on numerous material properties and their significant role in several technological applications it is of strong interest to find simple and robust mechanisms controlling the positioning and local number of TDs. We present a numerical study of TDs within effectively two dimensional closed soft films exhibiting in-plane orientational ordering. Popular examples of such class of systems are liquid crystalline shells and various biological membranes. We introduce the Effective Topological Charge Cancellation mechanism controlling localised positional assembling tendency of TDs and the formation of pairs {defect, antidefect} on curved surfaces and/or presence of relevant “impurities” (e.g. nanoparticles). For this purpose, we define an effective topological charge Δmeff consisting of real, virtual and smeared curvature topological charges within a surface patch Δς identified by the typical spatially averaged local Gaussian curvature K. We demonstrate a strong tendency enforcing Δmeff → 0 on surfaces composed of Δς exhibiting significantly different values of spatially averaged K. For Δmeff ≠ 0 we estimate a critical depinning threshold to form pairs {defect, antidefect} using the electrostatic analogy. PMID:27250777

  14. Effective Topological Charge Cancelation Mechanism

    NASA Astrophysics Data System (ADS)

    Mesarec, Luka; Góźdź, Wojciech; Iglič, Aleš; Kralj, Samo

    2016-06-01

    Topological defects (TDs) appear almost unavoidably in continuous symmetry breaking phase transitions. The topological origin makes their key features independent of systems’ microscopic details; therefore TDs display many universalities. Because of their strong impact on numerous material properties and their significant role in several technological applications it is of strong interest to find simple and robust mechanisms controlling the positioning and local number of TDs. We present a numerical study of TDs within effectively two dimensional closed soft films exhibiting in-plane orientational ordering. Popular examples of such class of systems are liquid crystalline shells and various biological membranes. We introduce the Effective Topological Charge Cancellation mechanism controlling localised positional assembling tendency of TDs and the formation of pairs {defect, antidefect} on curved surfaces and/or presence of relevant “impurities” (e.g. nanoparticles). For this purpose, we define an effective topological charge Δmeff consisting of real, virtual and smeared curvature topological charges within a surface patch Δς identified by the typical spatially averaged local Gaussian curvature K. We demonstrate a strong tendency enforcing Δmeff → 0 on surfaces composed of Δς exhibiting significantly different values of spatially averaged K. For Δmeff ≠ 0 we estimate a critical depinning threshold to form pairs {defect, antidefect} using the electrostatic analogy.

  15. Bone Cancer: Questions and Answers

    MedlinePlus

    ... determine the level of an enzyme called alkaline phosphatase. A large amount of this enzyme is present ... abnormal bone tissue. Because high levels of alkaline phosphatase are normal in growing children and adolescents, this ...

  16. ANOMALY STRUCTURE OF SUPERGRAVITY AND ANOMALY CANCELLATION

    SciTech Connect

    Butter, Daniel; Gaillard, Mary K.

    2009-06-10

    We display the full anomaly structure of supergravity, including new D-term contributions to the conformal anomaly. This expression has the super-Weyl and chiral U(1){sub K} transformation properties that are required for implementation of the Green-Schwarz mechanism for anomaly cancellation. We outline the procedure for full anomaly cancellation. Our results have implications for effective supergravity theories from the weakly coupled heterotic string theory.

  17. Urinary Mineral Concentrations in European Pre-Adolescent Children and Their Association with Calcaneal Bone Quantitative Ultrasound Measurements †

    PubMed Central

    Van den Bussche, Karen; Herrmann, Diana; De Henauw, Stefaan; Kourides, Yiannis A.; Lauria, Fabio; Marild, Staffan; Molnár, Dénes; Moreno, Luis A.; Veidebaum, Toomas; Ahrens, Wolfgang; Sioen, Isabelle

    2016-01-01

    This study investigates differences and associations between urinary mineral concentrations and calcaneal bone measures assessed by quantitative ultrasonography (QUS) in 4322 children (3.1–11.9 years, 50.6% boys) from seven European countries. Urinary mineral concentrations and calcaneal QUS parameters differed significantly across countries. Clustering revealed a lower stiffness index (SI) in children with low and medium urinary mineral concentrations, and a higher SI in children with high urinary mineral concentrations. Urinary sodium (uNa) was positively correlated with urinary calcium (uCa), and was positively associated with broadband ultrasound attenuation and SI after adjustment for age, sex and fat-free mass. Urinary potassium (uK) was negatively correlated with uCa but positively associated with speed of sound after adjustment. No association was found between uCa and QUS parameters after adjustment, but when additionally adjusting for uNa, uCa was negatively associated with SI. Our findings suggest that urinary mineral concentrations are associated with calcaneal QUS parameters and may therefore implicate bone properties. These findings should be confirmed in longitudinal studies that include the food intake and repeated measurement of urinary mineral concentrations to better estimate usual intake and minimize bias. PMID:27164120

  18. Adolescence physical activity is associated with higher tibial pQCT bone values in adulthood after 28-years of follow-up--the Cardiovascular Risk in Young Finns Study.

    PubMed

    Tolonen, S; Sievänen, H; Mikkilä, V; Telama, R; Oikonen, M; Laaksonen, M; Viikari, J; Kähönen, M; Raitakari, O T

    2015-06-01

    High peak bone mass and strong bone phenotype are known to be partly explained by physical activity during growth but there are few prospective studies on this topic. In this 28-year follow-up of Cardiovascular Risk in Young Finns Study cohort, we assessed whether habitual childhood and adolescence physical activity or inactivity at the age of 3-18 years were associated with adult phenotype of weight-bearing tibia and the risk of low-energy fractures. Baseline physical activity and data on clinical, nutritional and lifestyle factors were assessed separately for females and males aged 3-6-years (N=395-421) and 9-18-years (N=923-965). At the age of 31-46-years, the prevalence of low-energy fractures was assessed with a questionnaire and several tibial traits were measured with pQCT (bone mineral content (BMC; mg), total and cortical cross-sectional areas (mm(2)), trabecular (for the distal site only) and cortical (for the shaft only) bone densities (mg/cm(3)), stress-strain index (SSI; mm(3), for the shaft only), bone strength index (BSI; mg(2)/cm(4), for the distal site only) and the cortical strength index (CSI, for the shaft only)). For the statistical analysis, each bone trait was categorized as below the cohort median or the median and above and the adjusted odds ratios (OR) were determined. In females, frequent physical activity at the age of 9-18-years was associated with higher adulthood values of BSI, total and cortical areas, BMC, CSI and SSI at the tibia independently of many health and lifestyle factors (ORs 0.33-0.53, P≤0.05; P-values for trend 0.002-0.05). Cortical density at the tibial shaft showed the opposite trend (P-value for trend 0.03). Similarly in males, frequent physical activity was associated with higher values of adult total and cortical areas and CSI at the tibia (ORs 0.48-0.53, P≤0.05; P-values for trend 0.01-0.02). However, there was no evidence that childhood or adolescence physical activity was associated with lower risk of low

  19. Adolescence physical activity is associated with higher tibial pQCT bone values in adulthood after 28-years of follow-up--the Cardiovascular Risk in Young Finns Study.

    PubMed

    Tolonen, S; Sievänen, H; Mikkilä, V; Telama, R; Oikonen, M; Laaksonen, M; Viikari, J; Kähönen, M; Raitakari, O T

    2015-06-01

    High peak bone mass and strong bone phenotype are known to be partly explained by physical activity during growth but there are few prospective studies on this topic. In this 28-year follow-up of Cardiovascular Risk in Young Finns Study cohort, we assessed whether habitual childhood and adolescence physical activity or inactivity at the age of 3-18 years were associated with adult phenotype of weight-bearing tibia and the risk of low-energy fractures. Baseline physical activity and data on clinical, nutritional and lifestyle factors were assessed separately for females and males aged 3-6-years (N=395-421) and 9-18-years (N=923-965). At the age of 31-46-years, the prevalence of low-energy fractures was assessed with a questionnaire and several tibial traits were measured with pQCT (bone mineral content (BMC; mg), total and cortical cross-sectional areas (mm(2)), trabecular (for the distal site only) and cortical (for the shaft only) bone densities (mg/cm(3)), stress-strain index (SSI; mm(3), for the shaft only), bone strength index (BSI; mg(2)/cm(4), for the distal site only) and the cortical strength index (CSI, for the shaft only)). For the statistical analysis, each bone trait was categorized as below the cohort median or the median and above and the adjusted odds ratios (OR) were determined. In females, frequent physical activity at the age of 9-18-years was associated with higher adulthood values of BSI, total and cortical areas, BMC, CSI and SSI at the tibia independently of many health and lifestyle factors (ORs 0.33-0.53, P≤0.05; P-values for trend 0.002-0.05). Cortical density at the tibial shaft showed the opposite trend (P-value for trend 0.03). Similarly in males, frequent physical activity was associated with higher values of adult total and cortical areas and CSI at the tibia (ORs 0.48-0.53, P≤0.05; P-values for trend 0.01-0.02). However, there was no evidence that childhood or adolescence physical activity was associated with lower risk of low

  20. Measurements of tortuosity in stereolithographical bone replicas using audiofrequency pulses

    NASA Astrophysics Data System (ADS)

    Attenborough, Keith; Shin, Ho-Chul; Qin, Qin; Fagan, Michael J.; Langton, Christian M.

    2005-11-01

    The tortuosity of five air-filled stereolithographical cancellous bone replicas has been obtained from measurements using audiofrequency pulses in a rectangular waveguide. The data obtained from the replicas yields information about anisotropy with respect to orthogonal axes of the passages that would be marrow filled in vivo. A strong relationship has been found between the acoustically measured tortuosity and the independently measured porosity. Use of stereolithographical bone replicas has the potential to simulate perforation and thinning of cancellous bone and hence evaluate the dependence of acoustic properties on cancellous bone microstructure. As an ``extreme'' illustration of such use, ``inverses'' of the original replicas have been manufactured and acoustic measurements have been made on them. The data reveal significantly greater tortuosity of the passages that are geometrically equivalent to the original solid bone structures.

  1. Programmed administration of parathyroid hormone increases bone formation and reduces bone loss in hindlimb-unloaded ovariectomized rats

    NASA Technical Reports Server (NTRS)

    Turner, R. T.; Evans, G. L.; Cavolina, J. M.; Halloran, B.; Morey-Holton, E.

    1998-01-01

    Gonadal insufficiency and reduced mechanical usage are two important risk factors for osteoporosis. The beneficial effects of PTH therapy to reverse the estrogen deficiency-induced bone loss in the laboratory rat are well known, but the influence of mechanical usage in this response has not been established. In this study, the effects of programed administration of PTH on cancellous bone volume and turnover at the proximal tibial metaphysis were determined in hindlimb-unloaded, ovariectomized (OVX), 3-month-old Sprague-Dawley rats. PTH was administered to weight-bearing and hindlimb-unloaded OVX rats with osmotic pumps programed to deliver 20 microg human PTH (approximately 80 microg/kg x day) during a daily 1-h infusion for 7 days. Compared with sham-operated rats, OVX increased longitudinal and radial bone growth, increased indexes of cancellous bone turnover, and resulted in net resorption of cancellous bone. Hindlimb unloading of OVX rats decreased longitudinal and radial bone growth, decreased osteoblast number, increased osteoclast number, and resulted in a further decrease in cancellous bone volume compared with those in weight-bearing OVX rats. Programed administration of PTH had no effect on either radial or longitudinal bone growth in weight-bearing and hindlimb-unloaded OVX rats. PTH treatment had dramatic effects on selected cancellous bone measurements; PTH maintained cancellous bone volume in OVX weight-bearing rats and greatly reduced cancellous bone loss in OVX hindlimb-unloaded rats. In the latter animals, PTH treatment prevented the hindlimb unloading-induced reduction in trabecular thickness, but the hormone was ineffective in preventing either the increase in osteoclast number or the loss of trabecular plates. Importantly, PTH treatment increased the retention of a baseline flurochrome label, osteoblast number, and bone formation in the proximal tibial metaphysis regardless of the level of mechanical usage. These findings demonstrate that

  2. Multiscale imaging of bone microdamage

    PubMed Central

    Poundarik, Atharva A.; Vashishth, Deepak

    2015-01-01

    Bone is a structural and hierarchical composite that exhibits remarkable ability to sustain complex mechanical loading and resist fracture. Bone quality encompasses various attributes of bone matrix from the quality of its material components (type-I collagen, mineral and non-collagenous matrix proteins) and cancellous microarchitecture, to the nature and extent of bone microdamage. Microdamage, produced during loading, manifests in multiple forms across the scales of hierarchy in bone and functions to dissipate energy and avert fracture. Microdamage formation is a key determinant of bone quality, and through a range of biological and physical mechanisms, accumulates with age and disease. Accumulated microdamage in bone decreases bone strength and increases bone’s propensity to fracture. Thus, a thorough assessment of microdamage, across the hierarchical levels of bone, is crucial to better understand bone quality and bone fracture. This review article details multiple imaging modalities that have been used to study and characterize microdamage; from bulk staining techniques originally developed by Harold Frost to assess linear microcracks, to atomic force microscopy, a modality that revealed mechanistic insights into the formation diffuse damage at the ultrastructural level in bone. New automated techniques using imaging modalities such as microcomputed tomography are also presented for a comprehensive overview. PMID:25664772

  3. Bone histology in chronic kidney disease-related mineral and bone disorder.

    PubMed

    Kazama, Junichiro James

    2011-06-01

    A quantitative histological analysis of biopsied bone samples is currently regarded as the gold standard for a diagnosing procedure for bone diseases associated with chronic kidney disease-related mineral and bone disorder. Conventionally, "bone cell activities" and "bone mineralization" are applied as two independent assessment axes, and the histology results are classified into five categories according to these axes. Recently, a new bone histology classification system called the Turnover-Mineralization-Volume system, which applied "cancellous bone volume" as another major assessing axis, was advocated; however, both classification systems have many unsolved problems. Clinicians must realize the limitations in evaluating bone metabolism by bone histology. We will need to establish a new classification method for renal bone diseases independent of histological findings.

  4. Bone cysts: unicameral and aneurysmal bone cyst.

    PubMed

    Mascard, E; Gomez-Brouchet, A; Lambot, K

    2015-02-01

    Simple and aneurysmal bone cysts are benign lytic bone lesions, usually encountered in children and adolescents. Simple bone cyst is a cystic, fluid-filled lesion, which may be unicameral (UBC) or partially separated. UBC can involve all bones, but usually the long bone metaphysis and otherwise primarily the proximal humerus and proximal femur. The classic aneurysmal bone cyst (ABC) is an expansive and hemorrhagic tumor, usually showing characteristic translocation. About 30% of ABCs are secondary, without translocation; they occur in reaction to another, usually benign, bone lesion. ABCs are metaphyseal, excentric, bulging, fluid-filled and multicameral, and may develop in all bones of the skeleton. On MRI, the fluid level is evocative. It is mandatory to distinguish ABC from UBC, as prognosis and treatment are different. UBCs resolve spontaneously between adolescence and adulthood; the main concern is the risk of pathologic fracture. Treatment in non-threatening forms consists in intracystic injection of methylprednisolone. When there is a risk of fracture, especially of the femoral neck, surgery with curettage, filling with bone substitute or graft and osteosynthesis may be required. ABCs are potentially more aggressive, with a risk of bone destruction. Diagnosis must systematically be confirmed by biopsy, identifying soft-tissue parts, as telangiectatic sarcoma can mimic ABC. Intra-lesional sclerotherapy with alcohol is an effective treatment. In spinal ABC and in aggressive lesions with a risk of fracture, surgical treatment should be preferred, possibly after preoperative embolization. The risk of malignant transformation is very low, except in case of radiation therapy. PMID:25579825

  5. High-Dose α-Tocopherol Supplementation Does Not Induce Bone Loss in Normal Rats.

    PubMed

    Kasai, Shunji; Ito, Akemi; Shindo, Kaori; Toyoshi, Tohru; Bando, Masahiro

    2015-01-01

    Oxidative stress affects bone turnover. Preventative effects of antioxidants such as vitamin E on reduced bone mineral density and fractures associated with aging, osteoporosis, and smoking have been examined in animals and humans. The effects of vitamin E (α-tocopherol; αT) on bone health have yielded conflicting and inconclusive results from animal studies. In this study, to determine the bone effects of αT, we investigated the in vivo effects of αT on the bone mineral density, bone mass, bone microstructure, bone resorption, and osteogenesis through peripheral quantitative computed tomography (pQCT) measurements, micro-computed tomography (micro-CT) analyses, and bone histomorphometry of lumbar vertebrae and femurs in normal female Wistar rats fed diets containing αT in different quantities (0, 30, 120, or 600 mg/kg diet) for 8 weeks. To validate our hypotheses regarding bone changes, we examined ovariectomized rats as an osteoporosis model and control sham-operated rats in parallel. As expected, ovariectomized rats had reduced bone mineral density in lumbar vertebrae and the distal metaphyses of their femurs, reduced bone mass and deteriorated microstructure of cancellous bones in the vertebral body and distal femur metaphyses, and reduced bone mass due to resorption-dominant enhanced bone turnover in secondary cancellous bones in these sites. In comparison, αT administered to normal rats, even at the highest dose, did not induce reduced bone mineral density of lumbar vertebrae and femurs or a reduced bone mass or fragile microstructure of cancellous bones of the vertebral body and distal femur metaphyses. Instead, αT-fed rats showed a tendency for an osteogenesis-dominant bone mass increase in secondary cancellous bones in the vertebral body, in which active bone remodeling occurs. Thus, αT consumption may have beneficial effects on bone health. PMID:26147575

  6. Restoring and maintaining bone in osteopenic female rat skeleton: I. Changes in bone mass and structure

    NASA Technical Reports Server (NTRS)

    Tang, L. Y.; Jee, W. S.; Ke, H. Z.; Kimmel, D. B.

    1992-01-01

    This experiment contains the crucial data for the lose, restore, and maintain (LRM) concept, a practical approach for reversing existing osteoporosis. The LRM concept uses anabolic agents to restore bone mass and architecture (+ phase) and then switches to an agent with the established ability to maintain bone mass, to keep the new bone (+/- phase). The purpose of this study was to learn whether switching to an agent known chiefly for its ability to maintain existing bone mass preserves new bone induced by PGE2 in osteopenic, estrogen-depleted rats. The current study had three phases, the bone loss (-), restore (+), and maintain (+/-) phases. We ovariectomized (OX) or sham ovariectomized (sham-OX) 5.5-month-old female rats (- phase). The OX rats were treated 5 months postovariectomy with 1-6 mg PGE2 per kg/day for 75 days to restore lost cancellous bone mass (+ phase), and then PGE2 treatment was stopped and treatment began with 1 or 5 micrograms/kg of risedronate, a bisphosphonate, twice a week for 60 days (+/- phase). During the loss (-) phase, the cancellous bone volume of the proximal tibial metaphysis in the OX rat fell to 19% of initial and 30% of age-matched control levels. During the restore (+) phase, the cancellous bone volume in OX rats doubled. When PGE2 treatment was stopped, however, and no special maintenance efforts were made during the maintain (+/-) phase, the PGE2-induced cancellous bone disappeared. In contrast, the PGE2-induced cancellous bone persisted when the PGE2 treatment was followed by either a 1 or 5 micrograms treatment of risedronate per kg given twice a week for 60 days during the maintain (+/-) phase. The tibial shaft demonstrated very little cortical bone loss during the loss (-) phase in OX rats. The tibial shaft cortical bone fell some 8%. During the restore (+) phase, new cortical bone in OX rats increased by 22%. When PGE2 treatment was stopped and nothing was given during the maintain (+/-) phase, however, all but the PGE2

  7. Vascularized tail bone grafts in rats.

    PubMed

    Sempuku, T; Tamai, S; Mizumoto, S; Yajima, H

    1993-03-01

    A new experimental model for vascularized corticocancellous bone grafts was established by investigation of vascular anatomy of the tail in 15 adult Fischer 344 rats and determination of the viability of vascularized tail bone grafts into the abdominal wall in 22 7-week-old rats. The tail bones of 40 rats were then raised on the pedicle of the caudal artery and its venae comitantes, transferred to a resected portion in the femur, and observed for 16 weeks. The vascularized graft showed marked reactive periosteal bone formation during the first and second weeks following transfer, and thereafter, the graft continued to show active bone formation. In transverse section, the sharp processes became rounded. In the cancellous bone, both bone resorption and bone formation were noticeably activated early after transfer, although resorption predominated and the amount of the cancellous bone consequently diminished. The nonvascularized grafts showed "creeping substitution." The results suggest that morphologic adaptation occurs if living (i.e., vascularized) tail bones are transferred to long-bone femurs.

  8. The nonlinear transition period of broadband ultrasound attenuation as bone density varies.

    PubMed

    Serpe, L; Rho, J Y

    1996-07-01

    The purpose of this study was to determine whether a transition period occurs between cortical and cancellous bone in the relationship between ultrasound parameters [broadband ultrasound attenuation (BUA) and ultrasonic velocity] and density. Twenty-two cancellous bone discs wee obtained from proximal bovine tibiae. Also included were three samples of human vertebral cancellous bone from an elderly female and four samples of bovine cortical bone. Ultrasonic velocity did not show any transition period as density varied from cancellous to cortical bone. Ultrasonic velocity exhibited a definite linear dependence on density over the entire range examined. However, BUA has shown a transition period as density varied. Although BUA increased linearly with density for a low density cancellous bone tested (below 0.64 g cm-3), the dependence of BUA on density is nonlinear with a downwardly inflected parabola shape when covering a wide density range (0.130-0.913 g cm-3) of cancellous bone. When one includes cortical bone, the parabola tends to level off in a slow exponential decay. This nonlinear dependence may help to understand the characteristics of BUA measurement. PMID:8809627

  9. Improved CDMA Performance Using Parallel Interference Cancellation

    NASA Technical Reports Server (NTRS)

    Simon, Marvin; Divsalar, Dariush

    1995-01-01

    This report considers a general parallel interference cancellation scheme that significantly reduces the degradation effect of user interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each user the interference produced by the remaining users accessing the channel in an amount proportional to their reliability. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of user interference. The 1-stage interference cancellation is analyzed for three types of tentative decision devices, namely, hard, null zone, and soft decision, and two types of user power distribution, namely, equal and unequal powers. Simulation results are given for a multitude of different situations, in particular, those cases for which the analysis is too complex.

  10. Mechanotransduction of bone cells in vitro: mechanobiology of bone tissue.

    PubMed

    Mullender, M; El Haj, A J; Yang, Y; van Duin, M A; Burger, E H; Klein-Nulend, J

    2004-01-01

    Mechanical force plays an important role in the regulation of bone remodelling in intact bone and bone repair. In vitro, bone cells demonstrate a high responsiveness to mechanical stimuli. Much debate exists regarding the critical components in the load profile and whether different components, such as fluid shear, tension or compression, can influence cells in differing ways. During dynamic loading of intact bone, fluid is pressed through the osteocyte canaliculi, and it has been demonstrated that fluid shear stress stimulates osteocytes to produce signalling molecules. It is less clear how mechanical loads act on mature osteoblasts present on the surface of cancellous or trabecular bone. Although tissue strain and fluid shear stress both cause cell deformation, these stimuli could excite different signalling pathways. This is confirmed by our experimental findings, in human bone cells, that strain applied through the substrate and fluid flow stimulate the release of signalling molecules to varying extents. Nitric oxide and prostaglandin E2 values increased by between two- and nine-fold after treatment with pulsating fluid flow (0.6 +/- 0.3 Pa). Cyclic strain (1000 microstrain) stimulated the release of nitric oxide two-fold, but had no effect on prostaglandin E2. Furthermore, substrate strains enhanced the bone matrix protein collagen I two-fold, whereas fluid shear caused a 50% reduction in collagen I. The relevance of these variations is discussed in relation to bone growth and remodelling. In applications such as tissue engineering, both stimuli offer possibilities for enhancing bone cell growth in vitro.

  11. CancellationTools: All-in-one software for administration and analysis of cancellation tasks.

    PubMed

    Dalmaijer, Edwin S; Van der Stigchel, Stefan; Nijboer, Tanja C W; Cornelissen, Tim H W; Husain, Masud

    2015-12-01

    In a cancellation task, a participant is required to search for and cross out ("cancel") targets, which are usually embedded among distractor stimuli. The number of cancelled targets and their location can be used to diagnose the neglect syndrome after stroke. In addition, the organization of search provides a potentially useful way to measure executive control over multitarget search. Although many useful cancellation measures have been introduced, most fail to make their way into research studies and clinical practice due to the practical difficulty of acquiring such parameters from traditional pen-and-paper measures. Here we present new, open-source software that is freely available to all. It allows researchers and clinicians to flexibly administer computerized cancellation tasks using stimuli of their choice, and to directly analyze the data in a convenient manner. The automated analysis suite provides output that includes almost all of the currently existing measures, as well as several new ones introduced here. All tasks can be performed using either a computer mouse or a touchscreen as an input device, and an online version of the task runtime is available for tablet devices. A summary of the results is produced in a single A4-sized PDF document, including high quality data visualizations. For research purposes, batch analysis of large datasets is possible. In sum, CancellationTools allows users to employ a flexible, computerized cancellation task, which provides extensive benefits and ease of use.

  12. Cloaking through cancellation of diffusive wave scattering

    NASA Astrophysics Data System (ADS)

    Farhat, M.; Chen, P. Y.; Guenneau, S.; Bağc, H.; Salama, K. N.; Alù, A.

    2016-08-01

    A new cloaking mechanism, which makes enclosed objects invisible to diffusive photon density waves, is proposed. First, diffusive scattering from a basic core-shell geometry, which represents the cloaked structure, is studied. The conditions of scattering cancellation in a quasi-static scattering regime are derived. These allow for tailoring the diffusivity constant of the shell enclosing the object so that the fields scattered from the shell and the object cancel each other. This means that the photon flow outside the cloak behaves as if the cloaked object were not present. Diffusive light invisibility may have potential applications in hiding hot spots in infrared thermography or tissue imaging.

  13. Better Bones Buddies: An Osteoporosis Prevention Program

    ERIC Educational Resources Information Center

    Schrader, Susan L.; Blue, Rebecca; Horner, Arlene

    2005-01-01

    Although osteoporosis typically surfaces in later life, peak bone mass attained before age 20 is a key factor in its prevention. However, most American children's diets lack sufficient calcium during the critical growth periods of preadolescence and adolescence to achieve peak bone mass. "Better Bones (BB) Buddies" is an educational program…

  14. Bone Grafts

    MedlinePlus

    A bone graft transplants bone tissue. Surgeons use bone grafts to repair and rebuild diseased bones in your hips, knees, ... fractures or cancers. Once your body accepts the bone graft, it provides a framework for growth of new, ...

  15. Bone Diseases

    MedlinePlus

    ... avoid smoking and drinking too much alcohol. Bone diseases can make bones easy to break. Different kinds ... break Osteogenesis imperfecta makes your bones brittle Paget's disease of bone makes them weak Bones can also ...

  16. 78 FR 73587 - Taxpayer Advocacy Panel; Meeting Cancellation.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-06

    ... Internal Revenue Service Taxpayer Advocacy Panel; Meeting Cancellation. AGENCY: Internal Revenue Service... cancellation of the open meeting of the Taxpayer Advocacy Panel Taxpayer Communications Project Committee..., Acting Director, Taxpayer Advocacy Panel. BILLING CODE 4830-01-P...

  17. 37 CFR 2.111 - Filing petition for cancellation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... cancellation. (a) A cancellation proceeding is commenced by filing in the Office a timely petition for... representative, as specified in § 11.14(b) of this chapter. Electronic signatures pursuant to § 2.193(c)...

  18. Biologic augmentation of foot and ankle arthrodeses with an allogeneic cancellous sponge.

    PubMed

    Protzman, Nicole M; Galli, Melissa M; Bleazey, Scott T; Brigido, Stephen A

    2014-03-01

    This case series was conducted to assess the safety and efficacy of using an allogeneic cancellous bone sponge for augmentation of foot and ankle arthrodeses. Twenty-five patients were prospectively enrolled in the study prior to undergoing fusion and were then followed for 12 months postoperatively. There were 45 joints: 7 ankles, 12 subtalars, 12 talonaviculars, 6 calcaneocuboids, 1 naviculocuneiform, 6 first tarsometatarsals, and 1 second tarsometatarsal. Patient-reported outcomes of pain (visual analog scale) and function (American Orthopaedic Foot and Ankle Society score) were obtained preoperatively and postoperatively at 6 and 12 months. No complications were noted intraoperatively or during the follow-up period. Three months postoperatively, radiographic osseous union was noted in 52% (13/25) of patients, which further increased to 96% (24/25) of patients at 6 and 12 months. There was no statistically significant difference in union time between joints [H(6)=11.5; P=.08]. Statistically significant improvements in pain (P≤.002) and function (P<.001) were observed across assessments. This study demonstrated that the cancellous bone sponge appears to be a safe and efficacious product. Randomized controlled trials are warranted to determine if the allogeneic cancellous sponge improves fusion rate, pain, and function.

  19. The complexity of bone architecture: A tool to differentiate bone diseases

    NASA Astrophysics Data System (ADS)

    Saparin, Peter I.; Gowin, Wolfgang; Kurths, Jürgen; Felsenberg, Dieter

    2000-02-01

    We introduce a generalization of symbolic dynamics to analyze two-dimensional objects and propose measures of complexity to quantify the structure of symbol encoded images. This technique is applied to evaluate the architecture of human cancellous bone by analyzing computed tomography images of vertebrae acquired from specimens and in vivo. The pixels of the preprocessed images are encoded using a mixture of static and dynamic encoding. The architecture of encoded cancellous bone is evaluated as a whole using measures of complexity. A set of new parameters are introduced to quantify the different aspects of structure: complexity and degree of disorder of the architecture as a whole, or spatial arrangements of hard or soft elements of the bone separately. It is found that the complexity of the bone structure relates to its density exponentially. Normal bone has a complex ordered structure, while the architecture during the initial stage of bone loss is characterized by lower complexity and a maximal level of disorder. Increased bone loss leads again to ordered structure, however, its complexity is minimal. This phenomenon was observed in a series of osteoporotic specimens as well as in vivo in patients treated with fluor, and hormone replacement therapy. We found that different bone diseases demonstrate distinctive features captured by the measurements of complexity of the bone's structural composition. It is shown that the application of the proposed technique leads to new insights for understanding of the bone's response on medical treatment and provide important additional information for the diagnostics of bone diseases.

  20. Measurement of drag and its cancellation

    NASA Astrophysics Data System (ADS)

    DeBra, D. B.; Conklin, J. W.

    2011-05-01

    The design of drag cancellation missions of the future will take advantage of the technology experience of the past. The importance of data for modeling of the atmosphere led to at least six types of measurement: (a) balloon flights, (b) missile-launched falling spheres, (c) the 'cannonball' satellites of Ken Champion with accelerometers for low-altitude drag measurement (late 1960s and early 1970s), (d) the Agena flight of LOGACS (1967), a Bell MESA accelerometer mounted on a rotating platform to spectrally shift low-frequency errors in the accelerometer, (e) a series of French low-level accelerometers (e.g. CACTUS, 1975), and (f) correction of differential accelerations for drag errors in measuring gravity gradient on a pair of satellites (GRACE, 2002). The independent invention of the drag-free satellite concept by Pugh and Lange (1964) to cancel external disturbance added implementation opportunities. Its first flight application was for ephemeris prediction improvement with the DISCOS flight (1972)—still the only extended free test mass flight. Then successful flights for reduced disturbance environment for science measurement with gyros on GP-B (2004) and for improved accuracy in geodesy and ocean studies (GOCE, 2009) each using accelerometer measurements to control the drag-canceling thrust. LISA, DECIGO, BBO and other gravity wave-measuring satellite systems will push the cancellation of drag to new levels.

  1. 36 CFR 223.116 - Cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Cancellation. 223.116 Section 223.116 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS...

  2. Database Cancellation: The "Hows" and "Whys"

    ERIC Educational Resources Information Center

    Shapiro, Steven

    2012-01-01

    Database cancellation is one of the most difficult tasks performed by a librarian. This may seem counter-intuitive but, psychologically, it is certainly true. When a librarian or a team of librarians has invested a great deal of time doing research, talking to potential users, and conducting trials before deciding to subscribe to a database, they…

  3. 43 CFR 3108.3 - Cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING Relinquishment, Termination... law, the regulations issued thereunder, or the lease, the lease may be canceled by the Secretary, if the leasehold does not contain a well capable of production of oil or gas in paying quantities, or...

  4. Heineman Prize Lecture: Anomaly Cancellation: A Retrospective

    NASA Astrophysics Data System (ADS)

    Schwarz, John

    2002-04-01

    The mechanism by which gauge and gravitational anomalies cancel in certain string theories is reviewed. A few new tricks are introduced to make the derivation a little simpler, and the string-theoretic interpretation a little clearer, than in the original 1984 work.

  5. Experimental Demonstration of Underwater Acoustic Scattering Cancellation

    PubMed Central

    Rohde, Charles A.; Martin, Theodore P.; Guild, Matthew D.; Layman, Christopher N.; Naify, Christina J.; Nicholas, Michael; Thangawng, Abel L.; Calvo, David C.; Orris, Gregory J.

    2015-01-01

    We explore an acoustic scattering cancellation shell for buoyant hollow cylinders submersed in a water background. A thin, low-shear, elastic coating is used to cancel the monopole scattering from an air-filled, neutrally buoyant steel shell for all frequencies where the wavelength is larger than the object diameter. By design, the uncoated shell also has an effective density close to the aqueous background, independently canceling its dipole scattering. Due to the significantly reduced monopole and dipole scattering, the compliant coating results in a hollow cylindrical inclusion that is simultaneously impedance and sound speed matched to the water background. We demonstrate the proposed cancellation method with a specific case, using an array of hollow steel cylinders coated with thin silicone rubber shells. These experimental results are matched to finite element modeling predictions, confirming the scattering reduction. Additional calculations explore the optimization of the silicone coating properties. Using this approach, it is found that scattering cross-sections can be reduced by 20 dB for all wavelengths up to k0a = 0.85. PMID:26282067

  6. 36 CFR 223.116 - Cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Cancellation. 223.116 Section 223.116 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS...

  7. 36 CFR 223.116 - Cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Cancellation. 223.116 Section 223.116 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS...

  8. 36 CFR 223.116 - Cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Cancellation. 223.116 Section 223.116 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST PRODUCTS, AND FOREST BOTANICAL PRODUCTS...

  9. 25 CFR 213.40 - Cancellations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... FIVE CIVILIZED TRIBES, OKLAHOMA, FOR MINING Operations § 213.40 Cancellations. (a) When, in the opinion... or of the applicable regulations, or if mining operations are conducted wastefully and without regard to good mining practice, the Secretary of the Interior shall have the right at any time after 30...

  10. 25 CFR 213.40 - Cancellations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FIVE CIVILIZED TRIBES, OKLAHOMA, FOR MINING Operations § 213.40 Cancellations. (a) When, in the opinion... or of the applicable regulations, or if mining operations are conducted wastefully and without regard to good mining practice, the Secretary of the Interior shall have the right at any time after 30...

  11. 44 CFR 206.376 - Loan cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Loan cancellation. 206.376 Section 206.376 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... as a liability is incurred, regardless of the timing of related cash flows. (c) Revenue...

  12. 7 CFR 1956.130 - Cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of acceleration by written notice prior to the date of application. (b) Without application by debtor... bankruptcy shall be cancelled by the use of Form FmHA or its successor agency under Public Law 103-354 1956-1... its successor agency under Public Law 103-354 1956-1 will document: (i) The sources of...

  13. 7 CFR 1956.130 - Cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... of acceleration by written notice prior to the date of application. (b) Without application by debtor... bankruptcy shall be cancelled by the use of Form FmHA or its successor agency under Public Law 103-354 1956-1... its successor agency under Public Law 103-354 1956-1 will document: (i) The sources of...

  14. 7 CFR 1956.70 - Cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the note or other instrument, or because of acceleration by written notice prior to the date of application. Debts due the FmHA or its successor agency under Public Law 103-354 may be canceled upon... administrator, subject to the following conditions: (1) The FmHA or its successor agency under Public Law...

  15. 7 CFR 1956.70 - Cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the note or other instrument, or because of acceleration by written notice prior to the date of application. Debts due the FmHA or its successor agency under Public Law 103-354 may be canceled upon... administrator, subject to the following conditions: (1) The FmHA or its successor agency under Public Law...

  16. 7 CFR 1956.130 - Cancellation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... of acceleration by written notice prior to the date of application. (b) Without application by debtor... bankruptcy shall be cancelled by the use of Form FmHA or its successor agency under Public Law 103-354 1956-1... its successor agency under Public Law 103-354 1956-1 will document: (i) The sources of...

  17. 7 CFR 1956.130 - Cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... of acceleration by written notice prior to the date of application. (b) Without application by debtor... bankruptcy shall be cancelled by the use of Form FmHA or its successor agency under Public Law 103-354 1956-1... its successor agency under Public Law 103-354 1956-1 will document: (i) The sources of...

  18. 7 CFR 1956.70 - Cancellation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the note or other instrument, or because of acceleration by written notice prior to the date of application. Debts due the FmHA or its successor agency under Public Law 103-354 may be canceled upon... administrator, subject to the following conditions: (1) The FmHA or its successor agency under Public Law...

  19. 7 CFR 1956.70 - Cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the note or other instrument, or because of acceleration by written notice prior to the date of application. Debts due the FmHA or its successor agency under Public Law 103-354 may be canceled upon... administrator, subject to the following conditions: (1) The FmHA or its successor agency under Public Law...

  20. Method for Canceling Ionospheric Doppler Effect

    NASA Technical Reports Server (NTRS)

    Vessot, R. F. C.

    1982-01-01

    Unified transponder system with hydrogen-maser oscillators at both stations can compensate for both motional and ionospheric components of Doppler shift. Appropriate choices of frequency shift in output of mixer m3. System exploits proportionality between dispersive component of frequency shift and reciprocal of frequency to achieve cancellation of dispersive component at output.

  1. Advancements in Orthopedic Intervention: Retrograde Drilling and Bone Grafting of Osteochondral Lesions of the Knee Using Magnetic Resonance Imaging Guidance

    SciTech Connect

    Seebauer, Christian J.; Bail, Hermann J.; Rump, Jens C. Walter, Thula Teichgraeber, Ulf K. M.

    2010-12-15

    Computer-assisted surgery is currently a novel challenge for surgeons and interventional radiologists. Magnetic resonance imaging (MRI)-guided procedures are still evolving. In this experimental study, we describe and assess an innovative passive-navigation method for MRI-guided treatment of osteochondritis dissecans of the knee. A navigation principle using a passive-navigation device was evaluated in six cadaveric knee joint specimens for potential applicability in retrograde drilling and bone grafting of osteochondral lesions using MRI guidance. Feasibility and accuracy were evaluated in an open MRI scanner (1.0 T Philips Panorama HFO MRI System). Interactive MRI navigation allowed precise drilling and bone grafting of osteochondral lesions of the knee. All lesions were hit with an accuracy of 1.86 mm in the coronal plane and 1.4 mm the sagittal plane. Targeting of all lesions was possible with a single drilling. MRI allowed excellent assessment of correct positioning of the cancellous bone cylinder during bone grafting. The navigation device and anatomic structures could be clearly identified and distinguished throughout the entire drilling procedure. MRI-assisted navigation method using a passive navigation device is feasible for the treatment of osteochondral lesions of the knee under MRI guidance and allows precise and safe drilling without exposure to ionizing radiation. This method may be a viable alternative to other navigation principles, especially for pediatric and adolescent patients. This MRI-navigated method is also potentially applicable in many other MRI-guided interventions.

  2. 12 CFR 209.3 - Cancellation of Reserve Bank stock.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Cancellation of Reserve Bank stock. 209.3 Section 209.3 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM ISSUE AND CANCELLATION OF FEDERAL RESERVE BANK CAPITAL STOCK (REGULATION I) § 209.3 Cancellation...

  3. 46 CFR 308.511 - Cancellation of Open Cargo Policy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Cancellation of Open Cargo Policy. 308.511 Section 308... INSURANCE War Risk Cargo Insurance Ii-Open Policy War Risk Cargo Insurance § 308.511 Cancellation of Open Cargo Policy. An assured may cancel an Open Cargo Policy by delivering to the underwriting agent,...

  4. 25 CFR 273.62 - Cancelling a contract for cause.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Cancelling a contract for cause. 273.62 Section 273.62....62 Cancelling a contract for cause. (a) Any contract entered into under this part may be cancelled for cause when the contractor fails to perform the work called for under the contract or fails...

  5. 25 CFR 273.62 - Cancelling a contract for cause.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Cancelling a contract for cause. 273.62 Section 273.62....62 Cancelling a contract for cause. (a) Any contract entered into under this part may be cancelled for cause when the contractor fails to perform the work called for under the contract or fails...

  6. 25 CFR 273.62 - Cancelling a contract for cause.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Cancelling a contract for cause. 273.62 Section 273.62....62 Cancelling a contract for cause. (a) Any contract entered into under this part may be cancelled for cause when the contractor fails to perform the work called for under the contract or fails...

  7. 25 CFR 273.62 - Cancelling a contract for cause.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Cancelling a contract for cause. 273.62 Section 273.62....62 Cancelling a contract for cause. (a) Any contract entered into under this part may be cancelled for cause when the contractor fails to perform the work called for under the contract or fails...

  8. 25 CFR 273.62 - Cancelling a contract for cause.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Cancelling a contract for cause. 273.62 Section 273.62....62 Cancelling a contract for cause. (a) Any contract entered into under this part may be cancelled for cause when the contractor fails to perform the work called for under the contract or fails...

  9. 14 CFR 297.25 - Cancellation or conditioning of registration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Cancellation or conditioning of... § 297.25 Cancellation or conditioning of registration. The registration of a foreign indirect air carrier may be canceled or subjected to additional terms, conditions or limitations if: (a) It files...

  10. 26 CFR 301.6804-1 - Attachment and cancellation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Attachment and cancellation. 301.6804-1 Section 301.6804-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) PROCEDURE... Attachment and cancellation. For provisions relating to the attachment and cancellation of specific...

  11. 12 CFR 209.3 - Cancellation of Reserve Bank stock.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Cancellation of Reserve Bank stock. 209.3 Section 209.3 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM ISSUE AND CANCELLATION OF FEDERAL RESERVE BANK CAPITAL STOCK (REGULATION I) § 209.3 Cancellation...

  12. 48 CFR 52.217-2 - Cancellation Under Multiyear Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... canceled work; or (4) For service contracts, the remaining useful commercial life of facilities. Useful commercial life means the commercial utility of the facilities rather than their physical life with due... clause: Cancellation Under Multiyear Contracts (OCT 1997) (a) Cancellation, as used in this clause,...

  13. 48 CFR 52.217-2 - Cancellation Under Multiyear Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... canceled work; or (4) For service contracts, the remaining useful commercial life of facilities. Useful commercial life means the commercial utility of the facilities rather than their physical life with due... clause: Cancellation Under Multiyear Contracts (OCT 1997) (a) Cancellation, as used in this clause,...

  14. 5 CFR 870.906 - Cancellation of insurance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS (CONTINUED) FEDERAL EMPLOYEES' GROUP LIFE INSURANCE PROGRAM Assignments of Life Insurance § 870.906 Cancellation of insurance. (a) The right to cancel (or reduce) insurance transfers to the assignee... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Cancellation of insurance....

  15. 30 CFR 250.181 - When may the Secretary cancel my lease and when am I compensated for cancellation?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... cancellation? If the Secretary cancels your lease under this part or under 30 CFR part 256, you are entitled to... OPERATIONS IN THE OUTER CONTINENTAL SHELF General Primary Lease Requirements, Lease Term Extensions,...

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

    PubMed

    Willems, Nop M B K; Mulder, Lars; den Toonder, Jaap M J; Zentner, Andrej; Langenbach, Geerling 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 bone tissue stiffness was assessed in three directions using nanoindentation. At each of three tested sides 5 indents were made over the width of 5 single bone elements, resulting in a total number of 1500 indents. MicroCT was used to determine the local TMD at the indented sites. The TMD and the bone tissue stiffness were higher in bone from the adult animals than from the young ones, but did not differ between cancellous and cortical bone. In the adult group, both the TMD and the bone tissue stiffness were higher in the center than at the surface of the bone elements. The mean TMD, thus ignoring the local mineral distribution, had a coefficient of determination (R(2)) with the mean bone tissue stiffness of 0.55, p < 0.05, whereas the correlation between local bone tissue stiffness and the concomitant TMD appeared to be weak (R (2) 0.07, p < 0.001). It was concluded that the mineralization degree plays a larger role in bone tissue stiffness in cancellous than in cortical bone. Our data based on bone from the mandibular condyle suggest that the mineralization degree is not a decisive determinant of the local bone tissue stiffness.

  17. Arthroscopically assisted medial meniscal allograft transplantation using a modified bone plug to facilitate passage: surgical technique.

    PubMed

    Kim, Jin Goo; Lee, Yong Seuk; Lee, Soo Won; Kim, Young Jae; Kong, Doo Hwan; Ko, Min Soo

    2009-07-01

    This article describes a novel medial meniscal allograft transplantation method that permits easy passage of posterior bone plugs and facilitates bone-to-bone healing. With this method, an anterior bone plug with a long cylindrical shape is prepared, and the posterior bone plug is prepared using only a 2-mm deep, flat bone shell containing cancellous material with 6 baseball Ethibond stitches placed around it. The graft is divided into 3 portions, and boundaries of each are marked. Using a posteromedial portal, the posterior bony bed is prepared directly, and the exact anatomic location is visualized. This modified method facilitates graft passage as well as bone-to-bone healing.

  18. [Age-dependent decrease in plasma androgens, and role of androgens in bone mineral density and bone metabolism].

    PubMed

    Adachi, Masahiro; Takayanagi, Ryoichi

    2006-03-01

    Circulating plasma testosterone decreases by 0.5-1% per year after 40 age in men. Bone mineral density (BMD) in men also decreases by about 1% per year after age 40-60. Due to progression of an aging society, the frequency of osteoporosis in elderly men is gradually increased. Androgens have a major role in the growth and the maintenance of both cancellous and cortical bone mass in men. Androgen receptor is expressed in osteoblasts, osteoclasts and bone marrow stromal cells. Androgens have been shown to control the bone formation and resorption by regulating the expression and the activity of several cytokines and growth factors through androgen receptor. In addition to these direct actions, through the aromatase activity estrogens converted from androgens are converted to estrogens which act on bone tissues through estrogen receptor and play an important role in the homeostasis of cancellous and cortical bones in men. PMID:16508123

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

    PubMed Central

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

    2015-01-01

    Objectives 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. Methodology 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. Results 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. Conclusion 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. PMID:26309434

  20. The Burden of Surgical Cancellations and No-Shows

    PubMed Central

    Appavu, Sivasubramanian T.; Al-Shekaili, Salim M.; Al-Sharif, Ahmed M.; Elawdy, Mohamed M.

    2016-01-01

    Objectives: The operating theatre (OT) is a vital facility that utilises a considerable portion of the hospital’s budget; thus proper OT utilisation is essential. Surgical cancellation is a leading cause of OT underutilisation. This study aimed to report the rate and reasons for surgical cancellations and no-shows in a large regional hospital in Oman. Methods: This study took place as part of a retrospective quality management project at the Ibri Regional Hospital, Ibri, Oman. All elective surgical procedures scheduled between January and December 2014 were included. Cancelled procedures were reviewed to determine the reasons for cancellation. Results: A total of 4,814 elective procedures were scheduled during the study period; of these, 1,235 (26%) were cancelled. Patient no-shows were the most prevalent reason for surgical cancellation (63%), followed by surgical reasons (17%); in contrast, OT-associated reasons were responsible for only 2% of cancellations. According to speciality, general surgery had the highest percentage of total cancellations (65%), while ear, nose and throat had the highest rate of surgical cancellations among their scheduled cases (42%). Conclusion: Ibri Regional Hospital had a higher surgical cancellation rate due to no-shows than those reported in the literature. Regular audits, quality management projects and the appointment of a dedicated procedure booking coordinator may enhance proper utilisation of the OT, potentially saving funds, conserving resources and alleviating the burden of cancellations.

  1. The Burden of Surgical Cancellations and No-Shows

    PubMed Central

    Appavu, Sivasubramanian T.; Al-Shekaili, Salim M.; Al-Sharif, Ahmed M.; Elawdy, Mohamed M.

    2016-01-01

    Objectives: The operating theatre (OT) is a vital facility that utilises a considerable portion of the hospital’s budget; thus proper OT utilisation is essential. Surgical cancellation is a leading cause of OT underutilisation. This study aimed to report the rate and reasons for surgical cancellations and no-shows in a large regional hospital in Oman. Methods: This study took place as part of a retrospective quality management project at the Ibri Regional Hospital, Ibri, Oman. All elective surgical procedures scheduled between January and December 2014 were included. Cancelled procedures were reviewed to determine the reasons for cancellation. Results: A total of 4,814 elective procedures were scheduled during the study period; of these, 1,235 (26%) were cancelled. Patient no-shows were the most prevalent reason for surgical cancellation (63%), followed by surgical reasons (17%); in contrast, OT-associated reasons were responsible for only 2% of cancellations. According to speciality, general surgery had the highest percentage of total cancellations (65%), while ear, nose and throat had the highest rate of surgical cancellations among their scheduled cases (42%). Conclusion: Ibri Regional Hospital had a higher surgical cancellation rate due to no-shows than those reported in the literature. Regular audits, quality management projects and the appointment of a dedicated procedure booking coordinator may enhance proper utilisation of the OT, potentially saving funds, conserving resources and alleviating the burden of cancellations. PMID:27606108

  2. Sub-band adaptive noise cancelling

    NASA Astrophysics Data System (ADS)

    Ryan, James G.; Goubran, Rafik A.

    The technique of using sub-band adaptive filters for acoustic noise suppression is examined. Simulation results are presented for experimental systems trained with white noise and colored noise for both decimated and non-decimated sub-band signals. To illustrate the usefulness of the sub-band approach for a real application, the full band and sub-band noise cancellers were applied to car data. Estimates of the input and output power spectra for the different cases are presented. It is shown that the full-band noise canceller is unable to attenuate the noise in the higher frequencies due to the low input signal power in this region. The sub-band decomposition of the input signal can significantly increase the rate as compared to a full-band implementation under certain conditions. This increase in convergence speed is manifested as an increased noise attenuation in those regions of the input spectrum with relatively low amounts of power. In addition, the sub-band processing is seen to eliminate the noise enhancement phenomenon found in acoustic noise cancellers for mobile telephony.

  3. [Tibial bone harvesting technique for filling maxillary bone gaps in implantology].

    PubMed

    Aboul-Hosn, S; Monner, A; Juárez, I; Arranz, C; Díaz-Carandell, A; Marí, A; Piulachs, P

    2006-04-01

    We present an easy and quick technique of tibial bone grafting that can be used in maxillary bone losses, specially in implantology. The surgical technique is performed under general anaesthesia. A 1.5 cm skin incision is made on the anteromedial side of the tibia. Then the bone marrow can be approached through a cortical window drilled with a motorized trephine. At this stage, a disposable bone aspirator is used to collect the cancellous bone. At the end of the procedure, the periosteum, the subcutaneous tissues and the skin are sutured in three layers. The quantity of harvested cancellous bone varies from 18 to 30 cc. The procedure duration is about twenty minutes. The complication rate is low and the patients are able to walk a few hours after the procedure. They leave the hospital on the day after. Tibial bone harvesting is an alternative technique that can be chosen in cases with large bone defects. This tibial graft can be recommended because of its low morbidity, the quality of the bone and the short time duration of the procedure. Some details must be pointed out. A medial tibial surgical approach is for us better than a lateral approach because of its lower morbidity and because the bone is more superficial. The use of a motorized trephine is important to lift precisely the cortical bone window and because it is less traumatic than the hand trephine. The disposable bone aspirator is an excellent option to pick-up bone marrow with a minimum loss of bone material and in a shorter time.

  4. Healing of fractures with freeze-dried cortical bone plates. Comparison with compression plating.

    PubMed

    Malinin, T; Latta, L L; Wagner, J L; Brown, M D

    1984-11-01

    The healing of fractures of the radius with internal fixation by stainless-steel compression plates was compared with fractures fixed with freeze-dried bone-plate allografts. Fractures fixed with metallic plates gained slightly less than half the biomechanical strength of the contralateral control bone and healed without noticeable external callus formation. Bone-plated fractures regained three-fourths of the biomechanical strength of controls and healed by forming an external callus. Bone-plate allografts were eventually incorporated in the host bone. Allograft plates were vascularized and remodeled into cancellous bone in the process of incorporation in the host bones.

  5. Structural and cellular changes during bone growth in healthy children.

    PubMed

    Parfitt, A M; Travers, R; Rauch, F; Glorieux, F H

    2000-10-01

    Normal postnatal bone growth is essential for the health of adults as well as children but has never been studied histologically in human subjects. Accordingly, we analyzed iliac bone histomorphometric data from 58 healthy white subjects, aged 1.5-23 years, 33 females and 25 males, of whom 48 had undergone double tetracycline labeling. The results were compared with similar data from 109 healthy white women, aged 20-76 years, including both young adult reference ranges and regressions on age. There was a significant increase with age in core width, with corresponding increases in both cortical width and cancellous width. In cancellous bone there were increases in bone volume and trabecular thickness, but not trabecular number, wall thickness, interstitial thickness, and inferred erosion depth. Mineral apposition rates declined on the periosteal envelope and on all subdivisions of the endosteal envelope. Because of the concomitant increase in wall thickness, active osteoblast lifespan increased substantially. Bone formation rate was almost eight times higher on the outer than on the inner periosteum, and more than four times higher on the inner than on the outer endocortical surface. On the cancellous surface, bone formation rate and activation frequency declined in accordance with a fifth order polynomial that matched previously published biochemical indices of bone turnover. The analysis suggested the following conclusions: (1) Between 2 and 20 years the ilium grows in width by periosteal apposition (3.8 mm) and endocortical resorption (3.2 mm) on the outer cortex, and net periosteal resorption (0.4 mm) and net endocortical formation (1.0 mm) on the inner cortex. (2) Cortical width increases from 0.52 mm at age 2 years to 1.14 mm by age 20 years. To attain adult values there must be further endocortical apposition of 0.25 mm by age 30 years, at a time when cancellous bone mass is declining. (3) Lateral modeling drift of the outer cortex enlarges the marrow cavity

  6. Marked changes in iliac crest bone structure in postmenopausal osteoporotic patients without any signs of disturbed bone remodeling or balance.

    PubMed

    Steiniche, T; Christiansen, P; Vesterby, A; Hasling, C; Ullerup, R; Mosekilde, L; Melsen, F

    1994-01-01

    Successful iliac crest bone biopsies were obtained from 63 women with postmenopausal vertebral crush fracture osteoporosis. Structural and static histomorphometric parameters were compared with 25 age-matched normal females, who had suffered an unexpected and sudden death. The control group for dynamic parameters comprised 13 younger normal females. Marked structural changes were observed in the osteoporotic patients in cortical as well as cancellous bone. Cortical width, trabecular volume, trabecular bone surface density and trabecular number were all reduced, whereas trabecular separation and star volume were increased. On the other hand trabecular thickness was normal in the patients. These structural changes in cancellous bone indicate that extensive perforations of trabecular plates have occurred or that whole trabecular elements have been removed. The remodeling cycles of cancellous bone surface and the frequency by which they were repeated (activation frequency) did not differ significantly between osteoporotic patients and normal younger women. The bone balance per remodeling cycle in osteoporotic patients and controls was not significantly different. No subset of individuals in the group of osteoporotic patients could be identified regarding extent of resorptive and formative surfaces, bone formation rate or activation frequency. In the present osteoporotic patients nothing in the ongoing remodeling process could explain the marked changes in bone structure. The pathophysiological changes leading to osteoporosis may therefore occur earlier in life, maybe long before the manifestation of the disease. PMID:8024855

  7. Discussions on the Cancellation Effect on a Curved Orbit

    SciTech Connect

    Rui Li; Ya. S. Derbenev

    2005-05-16

    The canonical formulation and the cancellation effect for bunch dynamics under collective interaction on a curved orbit were presented in Ref. [*]. Some possible controversial representations of the cancellation effect were later addressed by Geloni et al.** In this study, we discuss all the points raised in Ref. [**] based on our canonical treatment, and show how these points can be perceived from the view point of the cancellation picture.

  8. Roentgenologic aspects of bone islands.

    PubMed

    Onitsuka, H

    1977-06-01

    A review of radiographs of 143 Adult Health Study and 46 non-sample subjects made over a period of 23 years established sites, sizes, ages at detection, and prevalence of 209 bone islands in 189 subjects. Except for 18 new bone islands, all appeared during the period of observation. Twenty-six of them changed: of these, 21 enlarged, 4 became smaller, and 1 disappeared. There was no association with atomic bomb radiation dose. Bone islands were more frequent in the pelvis and femora but often occurred in the ribs. Five bone islands in adolescents enlarged proportionally to bone growth, suggesting that they often participate metabolically in the normal osseous system. Bone islands must be differentiated from osteoblastic metastases.

  9. 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

    NASA Technical Reports Server (NTRS)

    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

  10. Adolescent development

    MedlinePlus

    Development - adolescent; Growth and development - adolescent ... During adolescence, children develop the ability to: Understand abstract ideas. These include grasping higher math concepts, and developing moral ...

  11. Scattering cancellation by metamaterial cylindrical multilayers

    NASA Astrophysics Data System (ADS)

    Tricarico, S.; Bilotti, F.; Vegni, L.

    2009-05-01

    In this paper, we present the theoretical analysis and the design of cylindrical multilayered electromagnetic cloaks based on the scattering cancellation technique. We propose at first the analysis and the design of bi-layered cylindrical shells, made of homogenous and isotropic metamaterials, in order to effectively reduce the scattered field from a dielectric cylindrical object. The single shell and the bi-layered shell cases are compared in terms of scattering reduction and loss effects. The comparison shows that the bi-layered configuration exhibits superior performances. The scattering cancellation approach, is, then, extended to the case of generic multilayered cylindrical shells, considering again homogeneous and isotropic metamaterials. The employment of the proposed technique to the case of cloaking devices working at multiple frequencies is also envisaged and discussed. Finally, some practical layouts of cylindrical electromagnetic cloaks working at optical frequencies are also proposed. In these configurations, the homogenous and isotropic metamaterials are replaced by their actual counterparts, obtained using alternating stacked plasmonic and non-plasmonic layers. The theoretical formulation and the design approaches presented throughout the paper are validated through proper full-wave numerical simulations.

  12. Driver Module for Noise Cancellation System

    NASA Astrophysics Data System (ADS)

    Shirvani, Mir S.

    2002-12-01

    The Driver module is an integral part of the noise cancellation system, which was my primary objective to research, design, and prototype during the tenure in NASA Langley research center. The function of the driver module is to actuate a panel that is constructed with a smart material and invented in NASA-LaRC. The bandwidth and amplitude of the actuation of the panel correlates the undesirable structural bandwidth and amplitude of the applied object. The undesirable structural bandwidth is relatively narrow and the undesirable amplitude is relatively large. A highly stable, low distortion, linear monolithic integrated circuit was used as a variable frequency and amplitude function generator. In order to elevate the amplitude of the output waveform of the generator to a sufficient magnitude a pair of high voltage monolithic MOSFET operational amplifiers were implemented. The amplifiers connected in a bipolar bridge configuration for a higher efficiency. In order to reduce the required external Supply voltages and make the driver capable to be operated by a battery a pair of ultra miniature high-output voltage dc to dc converters are also used. The driver module tested with the noise cancellation panel, the required data was acquired, and the result was promising. After examining all the options the driver module was designed and prototyped.

  13. Living Bones, Strong Bones

    NASA Video Gallery

    In this classroom activity, engineering, nutrition, and physical activity collide when students design and build a healthy bone model of a space explorer which is strong enough to withstand increas...

  14. A long term histological analysis of effect of interposed hydroxyapatite between bone and bone cement in THA and TKA.

    PubMed

    Oonishi, Hironobu

    2012-01-01

    The standard cementing technique for total hip and knee arthroplasty (THA, TKA) was modified by interposing osteoconductive porous polycrystalline hydroxyapatite (HA) granules at the cement-bone interface to augment cement-bone bonding. Twenty-one specimens from the acetabulum and two specimens from the femur containing well-fixed bone-cement interface were retrieved five months to twenty-two years after THA and TKA with an interface bioactive bone cement technique. Histological findings were evaluated in terms of the retrieved sites, the interval between index operation and revision, patient age at retrieval and bone pathology. Dense bone ingrowth was observed in all specimens retrieved from the superior wall of the acetabulum. Cancellous bone ingrowth was observed in specimens retrieved from the infero-medial wall of the acetabulum. Connective tissue interposition and osteolysis were observed at the sites where hydroxyapatite granules were absent. Findings of bone ingrowth for the HA interposed retrievals were similar regardless of the interval between index operation and revision, patient age at retrieval, and bone pathology. Longer survivability of the bone-cement bonding was attributed more to the interposed HA granules. In spite of various degrees of aging, postmenopausal osteoporosis, and pathological bone condition the histological findings were not affected by the bone pathology. There was long-term direct contact between the bone and hydroxyapatite granules. Thus, the interface bioactive bone cement technique can ensure longevity of bone-cement bonding even after the onset of osteoporosis and for pathological bone conditions.

  15. Bone Tumor

    MedlinePlus

    ... most common types of primary bone cancer are: • Multiple myeloma. Multiple myeloma is the most common primary bone cancer. It ... Any bone can be affected by this cancer. Multiple myeloma affects approximately six people per 100,000 each ...

  16. Bone Cancer

    MedlinePlus

    Cancer that starts in a bone is uncommon. Cancer that has spread to the bone from another ... more common. There are three types of bone cancer: Osteosarcoma - occurs most often between ages 10 and ...

  17. Alteration in bone geometric and mechanical properties, histomorphometrical parameters of trabecular bone, articular cartilage, and growth plate in adolescent rats after chronic co-exposure to cadmium and lead in the case of supplementation with green, black, red and white tea.

    PubMed

    Tomaszewska, Ewa; Dobrowolski, Piotr; Winiarska-Mieczan, Anna; Kwiecień, Małgorzata; Tomczyk, Agnieszka; Muszyński, Siemowit; Radzki, Radosław

    2016-09-01

    Adolescent male Wistar rats were used to check whether regular consumption of black, red, white, or green tea would have a protective effect on femur development during 12-week exposure to Cd and Pb (7mg Cd and 50mg Pb in 1kg of the diet). The animals were randomly divided (n=12) into a positive control (without Cd, Pb and teas), a negative control group (Cd and Pb), and groups supplemented additionally with green (GT), black (BT), red (RT), and white tea (WT). Heavy metals reduced the geometric and densitometric parameters and the total thickness of articular cartilage irrespective of tea administration and influenced mechanical endurance, growth plate thickness, and trabecular histomorphometry depending on the tea type. It is difficult to indicate which tea has the best protective effects on bone and hyaline cartilage against heavy metal action.

  18. Bone healing of an unfixed bone fragment of the distal segment in sagittal split ramus osteotomy.

    PubMed

    Park, Won-Jong; Hwang, Soon Jung

    2014-03-01

    In bilateral sagittal split ramus osteotomy for the correction of asymmetry of the mandible, yawing movement of the distal segment can displace the proximal segment. This displacement can be minimized through osteotomy of the posterior part of the distal segment (ie, distal cutting). This free bone fragment is usually removed because of the difficulty of fixation. No previous studies have examined whether union of the bone fragment after distal cutting could join and consequently strengthen the thinned mandibular posterior border. This study used CT imaging to evaluate bone union of the unfixed bone fragment at 3 months postoperatively. The location of the bone fragment and the morphology of bone healing were evaluated in 2D and 3D. The amount of cancellous bone healing between the free bone segment and the proximal segment averaged 63.69%. There was no correlation between the size of the bone gap and the degree of bone union. In most cases, the free bone fragment was located between the distal and proximal segments and tended to dislocate in an anterior-superior direction. Because the postoperative follow-up period was only 3 months, a longer-term study of the changes in bone volume after remodeling is necessary.

  19. 21 CFR 1305.28 - Canceling and voiding electronic orders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Canceling and voiding electronic orders. 1305.28... I AND II CONTROLLED SUBSTANCES Electronic Orders § 1305.28 Canceling and voiding electronic orders. (a) A supplier may void all or part of an electronic order by notifying the purchaser of the...

  20. 78 FR 14351 - Invasive Species Advisory Committee; Meeting Cancellation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    ... Office of the Secretary Invasive Species Advisory Committee; Meeting Cancellation AGENCY: Office of the Secretary, Interior. ACTION: Notice of meeting cancellation. SUMMARY: The meeting of the Invasive Species....gov . SUPPLEMENTARY INFORMATION: The ISAC is comprised of 31 nonfederal invasive species experts...

  1. 77 FR 16895 - Taxpayer Advocacy Panel Meeting Cancellation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... Internal Revenue Service Taxpayer Advocacy Panel Meeting Cancellation AGENCY: Internal Revenue Service (IRS... the open meeting of the Taxpayer Advocacy Panel Taxpayer Burden Reduction Project Committee scheduled... cancelled pending renewal of the Taxpayer Advocacy Panel Charter. FOR FURTHER INFORMATION CONTACT: Audrey...

  2. 77 FR 16895 - Taxpayer Advocacy Panel Meeting Cancellation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... Internal Revenue Service Taxpayer Advocacy Panel Meeting Cancellation AGENCY: Internal Revenue Service (IRS... open meeting of the Taxpayer Advocacy Panel Small Business/Self-Employed Decreasing Non-Filers Project... meeting is cancelled pending renewal of the Taxpayer Advocacy Panel Charter. FOR FURTHER...

  3. 32 CFR 1615.8 - Cancellation of registration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Cancellation of registration. 1615.8 Section 1615.8 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM ADMINISTRATION OF REGISTRATION § 1615.8 Cancellation of registration. The Director of Selective Service...

  4. 32 CFR 1615.8 - Cancellation of registration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Cancellation of registration. 1615.8 Section 1615.8 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM ADMINISTRATION OF REGISTRATION § 1615.8 Cancellation of registration. The Director of Selective Service...

  5. 32 CFR 1615.8 - Cancellation of registration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Cancellation of registration. 1615.8 Section 1615.8 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM ADMINISTRATION OF REGISTRATION § 1615.8 Cancellation of registration. The Director of Selective Service...

  6. 32 CFR 1615.8 - Cancellation of registration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Cancellation of registration. 1615.8 Section 1615.8 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM ADMINISTRATION OF REGISTRATION § 1615.8 Cancellation of registration. The Director of Selective Service...

  7. 32 CFR 1615.8 - Cancellation of registration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Cancellation of registration. 1615.8 Section 1615.8 National Defense Other Regulations Relating to National Defense SELECTIVE SERVICE SYSTEM ADMINISTRATION OF REGISTRATION § 1615.8 Cancellation of registration. The Director of Selective Service...

  8. 34 CFR 674.55 - Teacher cancellation-Defense loans.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false Teacher cancellation-Defense loans. 674.55 Section 674... POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION FEDERAL PERKINS LOAN PROGRAM Loan Cancellation § 674.55 Teacher... other nonprofit elementary or secondary school; (ii) An institution of higher education; or (iii)...

  9. 9 CFR 166.12 - Cancellation of licenses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Cancellation of licenses. 166.12 Section 166.12 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE SWINE HEALTH PROTECTION SWINE HEALTH PROTECTION General Provisions § 166.12 Cancellation...

  10. 9 CFR 166.12 - Cancellation of licenses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cancellation of licenses. 166.12 Section 166.12 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE SWINE HEALTH PROTECTION SWINE HEALTH PROTECTION General Provisions § 166.12 Cancellation...

  11. 77 FR 5012 - Rescission of Certain Product Cancellations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ... 010707-00055, which appeared in FR Doc. 2011-22135, published in the Federal Register of August 31, 2011 (76 FR 54230) (FRL-8885-6). The Cancellation Order was issued following a Notice announcing the... (76 FR 31380(FRL- 8857-1) . However, the request to voluntarily cancel this pesticide product had...

  12. 40 CFR 152.99 - Petitions to cancel registration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Protection of Data Submitters' Rights § 152.99 Petitions to cancel registration. An original data submitter... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Petitions to cancel registration. 152.99 Section 152.99 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  13. 30 CFR 281.47 - Cancellation of leases.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Cancellation of leases. 281.47 Section 281.47... OTHER THAN OIL, GAS, AND SULPHUR IN THE OUTER CONTINENTAL SHELF Termination of Leases § 281.47 Cancellation of leases. (a) Whenever the owner of a nonproducing lease fails to comply with any of...

  14. 30 CFR 282.15 - Cancellation of leases.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Cancellation of leases. 282.15 Section 282.15... § 282.15 Cancellation of leases. (a) Whenever the owner of a nonproducing lease fails to comply with any of the provisions of the Act, the lease, or the regulations issued under the Act, and the...

  15. 42 CFR 57.213a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.213a Loan cancellation reimbursement. (a) For loans made prior to October 22... 42 Public Health 1 2013-10-01 2013-10-01 false Loan cancellation reimbursement. 57.213a Section...

  16. 42 CFR 57.213a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.213a Loan cancellation reimbursement. (a) For loans made prior to October 22... 42 Public Health 1 2014-10-01 2014-10-01 false Loan cancellation reimbursement. 57.213a Section...

  17. 42 CFR 57.313a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Nursing Student Loans § 57.313a Loan cancellation reimbursement. In the event that insufficient funds are available to... 42 Public Health 1 2014-10-01 2014-10-01 false Loan cancellation reimbursement. 57.313a Section...

  18. 42 CFR 57.313a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Nursing Student Loans § 57.313a Loan cancellation reimbursement. In the event that insufficient funds are available to... 42 Public Health 1 2013-10-01 2013-10-01 false Loan cancellation reimbursement. 57.313a Section...

  19. 42 CFR 57.213a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.213a Loan cancellation reimbursement. (a) For loans made prior to October 22... 42 Public Health 1 2011-10-01 2011-10-01 false Loan cancellation reimbursement. 57.213a Section...

  20. 42 CFR 57.313a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Nursing Student Loans § 57.313a Loan cancellation reimbursement. In the event that insufficient funds are available to... 42 Public Health 1 2011-10-01 2011-10-01 false Loan cancellation reimbursement. 57.313a Section...

  1. 42 CFR 57.213a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.213a Loan cancellation reimbursement. (a) For loans made prior to October 22... 42 Public Health 1 2012-10-01 2012-10-01 false Loan cancellation reimbursement. 57.213a Section...

  2. 42 CFR 57.213a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.213a Loan cancellation reimbursement. (a) For loans made prior to October 22... 42 Public Health 1 2010-10-01 2010-10-01 false Loan cancellation reimbursement. 57.213a Section...

  3. 42 CFR 57.313a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Nursing Student Loans § 57.313a Loan cancellation reimbursement. In the event that insufficient funds are available to... 42 Public Health 1 2010-10-01 2010-10-01 false Loan cancellation reimbursement. 57.313a Section...

  4. 42 CFR 57.313a - Loan cancellation reimbursement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONSTRUCTION OF TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Nursing Student Loans § 57.313a Loan cancellation reimbursement. In the event that insufficient funds are available to... 42 Public Health 1 2012-10-01 2012-10-01 false Loan cancellation reimbursement. 57.313a Section...

  5. 78 FR 30932 - National Cancer Institute; Cancellation of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health National Cancer Institute; Cancellation of Meeting Notice is hereby given of the cancellation of the National Cancer Institute Special Emphasis Panel, June 7, 2013, 10:00 a.m. to June 7, 2013, 1:00...

  6. Active noise canceling system for mechanically cooled germanium radiation detectors

    DOEpatents

    Nelson, Karl Einar; Burks, Morgan T

    2014-04-22

    A microphonics noise cancellation system and method for improving the energy resolution for mechanically cooled high-purity Germanium (HPGe) detector systems. A classical adaptive noise canceling digital processing system using an adaptive predictor is used in an MCA to attenuate the microphonics noise source making the system more deployable.

  7. 30 CFR 282.15 - Cancellation of leases.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Cancellation of leases. 282.15 Section 282.15 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE... Jurisdiction and Responsibilities of Director § 282.15 Cancellation of leases. (a) Whenever the owner of...

  8. 75 FR 30386 - Cancellation Notice of a Sunshine Act Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-01

    ... From the Federal Register Online via the Government Publishing Office ELECTION ASSISTANCE COMMISSION Cancellation Notice of a Sunshine Act Meeting AGENCY: United States Election Assistance Commission (EAC). ACTION: Notice to cancel EAC public meeting. SUMMARY: The U.S. Election Assistance...

  9. 75 FR 33628 - National Cancer Institute; Cancellation of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-14

    ... HUMAN SERVICES National Institutes of Health National Cancer Institute; Cancellation of Meeting Notice is hereby given of the cancellation of the National Cancer Institute Clinical Trials and Translational Research Advisory Committee, July 14, 2010, 8 a.m. to July 14, 2010, 4 p.m., National...

  10. 77 FR 34396 - National Cancer Institute; Cancellation of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-11

    ... HUMAN SERVICES National Institutes of Health National Cancer Institute; Cancellation of Meeting Notice is hereby given of the cancellation of the National Cancer Institute Clinical Trials and Translational Research Advisory Committee, July 11, 2012, 9:00 a.m. to July 11, 2012, 4:00 p.m.,...

  11. 78 FR 69432 - National Institute on Aging; Cancellation of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-19

    ... November 8, 2013, 67177 FR 217. The meeting was entitled Member Conflict. Dated: November 13, 2013. Melanie... HUMAN SERVICES National Institutes of Health National Institute on Aging; Cancellation of Meeting Notice is hereby given of the cancellation of the National Institute on Aging Special Emphasis...

  12. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  13. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  14. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  15. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  16. 14 CFR 221.211 - Cancellation of suspended matter.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Cancellation of suspended matter. 221.211 Section 221.211 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION... matter. When, pursuant to an order of the Department, the cancellation of rules, fares, charges, or...

  17. 14 CFR 1215.110 - User cancellation of all services.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false User cancellation of all services. 1215.110... RELAY SATELLITE SYSTEM (TDRSS) Use and Reimbursement Policy for Non-U.S. Government Users § 1215.110 User cancellation of all services. The user has the right to terminate its service contract with...

  18. 19 CFR 111.51 - Cancellation of license or permit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Without prejudice. The Assistant Commissioner may cancel a broker's license or permit “without prejudice... in order to avoid those proceedings, he may cancel the license or permit “without prejudice” only with authorization from the Secretary of Homeland Security, or his designee. (b) With prejudice....

  19. 34 CFR 674.55 - Teacher cancellation-Defense loans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Teacher cancellation-Defense loans. 674.55 Section 674... POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION FEDERAL PERKINS LOAN PROGRAM Loan Cancellation § 674.55 Teacher... majority of the students whom the borrower teaches are children. (Authority: 20 U.S.C. 425(b)(3))...

  20. 77 FR 27072 - Gastrointestinal Drugs Advisory Committee; Cancellation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-08

    ... Federal Register of March 23, 2012 (77 FR 17078). The meeting is being canceled because the Agency no... HUMAN SERVICES Food and Drug Administration Gastrointestinal Drugs Advisory Committee; Cancellation AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The meeting of the...