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  • 1
    Electronic Resource
    Electronic Resource
    Cytokine Release from Marrow Mononuclear Cells is Negatively Correlated to Cortical Elasticity in Non-Osteoporotic Postmenopausal Women (1998)
    Springer
    Calcified tissue international 62 (1998), S. 13-16 
    Details
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Activation of bone remodeling is likely to be under the control of mechanical factors acting, in part, through soluble local factors. We therefore investigated a relationship between cytokine production by marrow cells and bone elasticity. We studied 36 non-osteoporotic postmenopausal women undergoing hip arthroplasty for hip arthrosis (mean age: 68 ± 8 years; lumbar BMD Z-score: +0.54 ± 0.33 SD). Adherent marrow mononuclear cells were cultured for 48 hours with autologous plasma, and supernatants were harvested for PGE2, IL-1, TNF-α, and IL-6 measurements. Femoral neck cortical bones were removed during surgery for cortical histomorphometric evaluation and determination of elasticity indices (C33) using ultrasonic transmission method. In this nonosteoporotic population, femoral neck longitudinal elasticity indices were inversely correlated to both cortical thickness (r=−0.58, P 〈 0.01) and cortical porosity (r=−0.33, P 〈 0.01). The longitudinal elasticity indices were also negatively correlated to basal IL-1 and TNF-α release by adherent mononuclear marrow cells (r=−0.59, P 〈 0.01; r=−0.60, P 〈 0.01, respectively). However, no relationship was found between the three cytokines tested and either cortical thickness or porosity. These data show a link between cortical biomechanical properties and local factors involved in bone remodeling. We suggest that increased bone elasticity decreases transmission of strain, which in turn decreases cytokine release from marrow cells. However, whether cytokines influence bone elasticity or vice versa remains to be demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900386
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  • 2
    Electronic Resource
    Electronic Resource
    Natural coral as a substrate for fibroblastic growth in vitro (1993)
    Springer
    Journal of materials science 4 (1993), S. 575-581 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Coral skeleton is a naturally porous material. This biomaterial is nowadays currently used in humans as a bone graft substitute. Its open porosity provides a large area for potential cell adhesion and for this reason fibroblastic cell proliferation into this material was investigated. McCoy's human fibroblasts were cultured on coral specimens; cell viability and propagation were evaluated by the means of an MTT test and manual counting. Due to the biomaterial porosity, numerous technical adjustments were necessary to ensure an acceptable cell development and evaluation of cell populations. Cell population was evaluated every 3 days over a 24-day period. When compared to cell growth on culture membranes, fibroblasts grew slower on coral during the early time periods, but increased to 2.2 times that of controls from the 12th day after seeding. Natural coral seems to offer a suitable surface for large fibroblastic culture and could be an interesting alternative to synthetic substrates traditionally used for this purpose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00125596
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  • 3
    Electronic Resource
    Electronic Resource
    The effect of drilling parameters on bone (1994)
    Springer
    Journal of materials science 5 (1994), S. 225-231 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: For biocompatibility evaluation, orthopaedic and dental biomaterials are often implanted into bone after drilling. Bone repair in the drilled hole may be affected by bone damage attributed to drilling, thus influencing the bone response to biomaterials. The drilling parameters (the speed of rotation and irrigation) were investigated histologically. Three holes were drilled in each rabbit tibia with different conditions; three speeds (200, 500 and 5000 r.p.m.) and the use of central irrigation or not. Rabbits were killed immediately, 3 days, 2 weeks or 4 weeks post-operatively. India ink was injected in several rabbits just after drilling to investigate the extent of local ischaemia. The drilling quality was evaluated with regard to hole geometry, initial thermal damage and later bone healing process. For 500 or 200 r.p.m. the initial thermal damage, shown by the degree of ischaemia, was less than for 5000 r.p.m. drilling, but the hole edge was not always cleanly cut. This uneven cut edge was considered not to influence the bone-healing process. Drilling at 200 r.p.m. introduced a lower degree of circularity. The subsequent bone formation was retarded by 5000 r.p.m. drilling, presumably due to thermal damage and vascular obstructions. The irrigation was effective in reducing the ischaemic area. These results suggest that a speed of about 500 r.p.m. may be recommendable for intraosseous implantation of biomaterials. The central irrigation system is considered effective in reducing the ischaemic area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121093
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of drilling parameters on bone (1994)
    Springer
    Journal of materials science 5 (1994), S. 237-241 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: For biocompatibility testing, cylindrical specimens are often inserted into drilled cortical defects. However, little attention has been paid to the drilling conditions. Our previous experience revealed that bone formation in drilled cortial defects was delayed by 5000 r.p.m. drilling due to thermal necrosis around the hole compared with 500 r.p.m., and the use of irrigation was effective in reducing the degree of local ischaemia. Therefore, this experiment was performed to investigate the short- and long-term effects of the drilling conditions on bone response to cylindrical porous hydroxyapatite implants. Two holes were drilled in rabbit tibia diaphysis with two different drilling conditions: 500 r.p.m. with irrigation and 5000 r.p.m. without irrigation. Rabbits were killed at 2 or 12 weeks post-operatively. The bone formation on the hole edge, on the implant surface and within the implant pores was investigated. At 2 weeks post-operatively the area of newly formed bone within the implant pores at 500 r.p.m. was significantly greater, whereas there was no difference at 12 weeks. These results indicate that the drilling conditions affect the short-term bone response to the implants. Therefore, the drilling conditions must be taken into consideration when investigating the early bone response to materials implanted into drilled cortical defects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121095
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  • 5
    Electronic Resource
    Electronic Resource
    A histomorphometric comparison of the muscular tissue reaction to stainless steel, pure titanium and titanium alloy implant materials (1991)
    Springer
    Journal of materials science 2 (1991), S. 1-8 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Thein vivo tissue reaction to titanium and titanium-based alloys using quantitative histomorphometry was investigated. According to the guidelines for biomaterials testing suggested by ISO, 2 mm × 6 mm cylindrical specimens of chemically pure (CP) Ti, TiO2, electrolytically coated Ti, Ti6Al4V, TiO2-coated Ti6Al4V, TiN physical vapour deposition-coated Ti6Al4V and Ti5Al2.5Fe were implanted in the paravertebral muscles of rats, for 1–52 weeks, 316L stainless steel being used as a control implant material. After PMMA embedding, electrochemical dissolution of the implants, microtome sectioning and Masson's trichrome staining, the tissue reaction was assayed using a semi-automatic method based on the digitization of both the encapsulating membrane contours and the different cell types located within it. All materials induced a close tissue reaction. There was no statistical difference between the tested materials regarding the time-evolution of the inflammatory cells. However, when comparing CP Ti with 316L, a significant difference was found in the fibrocyte kinetics: in the short term, fibrocyte densities were lower for 316L, while beyond 12 weeks, they exhibited higher values than CP Ti. To a lesser extent, a similar observation was made when comparing CP Ti with Ti5Al12.5Fe. No statistical difference was found in the comparison of CP Ti with Ti6Al4V. The membrane thickness was identical for all tested materials and appeared not to be time-dependent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00701681
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  • 6
    Electronic Resource
    Electronic Resource
    A generalized method for characterizing elastic anisotropy in solid living tissues (1990)
    Springer
    Journal of materials science 1 (1990), S. 1-8 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The microstructure of cortical bone may exhibit either transverse isotropic or orthotropic symmetry, thus requiring either five or nine independent elastic stiffness coefficients (or compliances), respectively, to describe its elastic anisotropy. Our previous analysis to describe this anisotropy in terms of two scalar quantities for the transverse isotropic case is extended here to include orthotropic symmetry. The new results for orthotropic symmetry are compared with previous calculations using the transverse isotropic analysis on the same sets of anisotropic elastic constants for bone, determined either by mechanical or by ultrasonic experiments. In addition, the orthotropic calculation has been applied to full sets of orthotropic elastic stiffness coefficients of a large variety of wood species. Although having some resemblance to plexiform bone in microstructural organization, there is a dramatic difference in both the shear and the compressive elastic anisotropy between the two materials: wood is at least one order of magnitude more anisotropic than bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705346
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of drilling parameters on bone (1994)
    Springer
    Journal of materials science 5 (1994), S. 232-236 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: For orthopaedic biomaterial implantation testing, specimens are often implanted into cortical bone defects. The implantation site is assumed to be one of the factors that influence the bone response to biomaterials. The aim of this study was to investigate the bone-healing process in drilled cortical defects at different sites with respect to time. Sheep metatarsus was implemented, since it is a long straight bone with four flat faces. Thus, the different drilling sites were obtained by changing the longitudinal level (proximal, middle and distal) and bone aspect (anterior, lateral and posterior). Metatarsi were obtained at 1, 2, 3 and 4 months post-operatively and with non-decalcified sections the newly formed bone area was measured using a microscope connected to an image analyser. The rate of bone formation was higher in the anterior aspect (P〈0.05). The new bone did not form concentrically from the hole edge towards the centre, and the principal direction of bone growth was different between the anterior and the posterior aspects (P〈0.05). However, there was no difference with respect to the longitudinal axis. These results indicate that the implantation site must be considered when analysing the bone response to biomaterials implanted in cortical defects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121094
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  • 8
    Electronic Resource
    Electronic Resource
    Circulating stable antigens at higher levels down-regulate antibody responses toPlasmodium falciparum (1993)
    Springer
    Parasitology research 79 (1993), S. 163-167 
    Details
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A study involving 169 schoolchildren (5–14 years old) living in Manarintsoa near Antananarivo (Madagascar, East Africa) was performed during the seasonal malaria transmission period. For the whole population examined, the prevalence ofPlasmodium falciparum and the rates of spleen enlargement and of circulating stable antigen (S-Ag) were found to be 60.9%, 71.7%, and 46,8%, respectively. The prevalence of IgG antibody to RESA (ring-infected erythrocyte surface antigen) was 42.7% and that of IgG and IgM antibodies to E-Ag (exoantigens) was 44.9% and 2.9%, respectively. The positive rates for IgG and IgM antibodies to Som-Ag (somatic antigen) were 48.5% and 5.9%, respectively. Concerning S−Ag, no significant relationship was observed for parasitemia, spleen size, age, or IgM antibody responses to exoantigens (E-Ag) or to somatic antigen (Som-Ag). Levels of S−Ag were found to be related to IgG antibodies to E-Ag. Our results suggest that S−Ag at low levels may participate in the mechanisms involved in the development of the IgG antibody responses to E-Ag and to Som-Ag, whereas at a comparative population level, higher quantities of S−Ag down-regulate antibody responses toP. falciparum. The data we obtained were compared with those gathered in another malaria mesoendemic area (Bobo-Dioulasso, Burkina Faso, West Africa), where lower levels of S−Ag were found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00932264
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  • 9
    Electronic Resource
    Electronic Resource
    A new apparatus for studying the effect of hydrostatic pressure on cells in culture (1996)
    Springer
    Cytotechnology 21 (1996), S. 21-30 
    Details
    ISSN: 1573-0778
    Keywords: hydrostatic pressure ; mechanical stress ; osteoblasts ; ROS 17/2.8
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Although mechanical stresses have long been recognized as an important factor in the regulation of bone remodeling, the mechanism underlying this effect has remained obscure. A number of methods have been devised to apply forces to bone tissues and bone-derived cells in order to investigate the biochemical results of mechanical stimuli. In this paper we report a method for applying a well controlled cyclic hydrostatic pressure on cultured ROS 17/2.8 osteoblastic lineage cells. This technique allows the investigation of the true frequency response of cells. Hydrostatic pressure with a 1 Hz frequency decreases alkaline phosphatase activity of confluent osteoblastic-like cells (ROS 17/2.8).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00364834
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  • 10
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    Lentiviral vectors for gene transfer into the spinal cord glial cells (2009)
    Springer Nature
    Details
    Publication Date: 2009-02-26
    Print ISSN: 0969-7128
    Electronic ISSN: 1476-5462
    Topics: Biology , Medicine
    Published by Springer Nature
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