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  • 1
    Electronic Resource
    Electronic Resource
    Mechanical implications of collagen fibre orientation in cortical bone of the equine radius (1993)
    Springer
    Anatomy and embryology 187 (1993), S. 239-248 
    Details
    ISSN: 1432-0568
    Keywords: Collagen orientation ; Bone ; Stress ; Strain ; Adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Mechanical test specimens were prepared from the cranial and caudal cortices of radii from eight horses. These were subjected to destructive tests in either tension or compression. The ultimate stress, elastic modulus and energy absorbed to failure were calculated in either mode of loading. Analysis was performed on the specimens following mechanical testing to determine their density, mineral content, mineral density distribution and histological type. A novel technique was applied to sections from each specimen to quantify the predominant collagen fibre orientation of the bone near the plane of fracture. The collagen map for each bone studied was in agreement with the previously observed pattern of longitudinal orientation in the cranial cortex and more oblique to transverse collagen in the caudal cortex. Bone from the cranial cortex had a significantly higher ultimate tensile stress (UTS) than that from the caudal cortex (160 MPa vs 104 MPa; P〈0.001) though this trend was reversed in compression, the caudal cortex becoming relatively stronger (185 MPa vs 217 MPa; P〈0.01). Bone from the cranial cortex was significantly suffer than that from the caudal cortex both in tension (22 GPa vs 15 GPa; P〈0.001) and compression (19 GPa vs 15 GPa; P〈0.01). Of all the histo-compositional variables studied, collagen fibre orientation was most closely correlated with mechanical properties, accounting for 71% of variation in ultimate tensile stress and 58% of variation in the elastic modulus. Mineral density and porosity were the only other variables to show any significant correlation with either UTS or elastic modulus. The variations in mechanical properties around the equine radius, which occur in close association with the different collagen fibre orientations, provide maximal safety factors in terms of ultimate stress, yet contribute to greater bending of the bone as it is loaded during locomotion, and thus lower safety factors through the higher strains this engenders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195761
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Use of a genetically attenuated strain of Aeromonas salmonicida to vaccinate salmonid fish (1996)
    Springer
    Aquaculture international 4 (1996), S. 55-66 
    Details
    ISSN: 1573-143X
    Keywords: Aeromonas salmonicida ; aroA ; β-galactosidase ; Furunculosis ; Genetically attenuated live vaccine ; Immune response ; Salmonids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A genetically attenuated strain of Aeromonas salmonicida has been developed that has a complete deletion of the aroA gene (Brivax II), making it suitable for development as a commercial vaccine. Brivax II was effectively cleared from Atlantic salmon, Salmo salar, a species highly susceptible to furunculosis, confirming that it is attenuated. Clearance rate was dependent on the vaccine dose administered, being longer with higher doses. Immunological studies using Brivax II injected in rainbow trout, Oncorhynchus mykiss, confirmed that live vaccines stimulate a greater response, in terms of generating leucocytes able to proliferate to a subsequent encounter with antigen, relative to killed vaccines. Development of strains of Brivax II as carriers of heterologous antigens was also investigated. Escherichia coli Β-galactosidase was chosen as the model antigen, and three strains containing plasmids with the LacZ gene were constructed (Brivax 12, Brivax 61 and Brivax 107). All three strains were shown to express Β-galactosidase in vivo in rainbow trout and to be cleared effectively. Interestingly, Brivax 107 was cleared faster than the other two Lac+ strains and had the highest level of Β-galactosidase activity. The two strains expressing lower levels of activity also behaved differently in vivo, in that Brivax 12 accumulated derivatives expressing lower levels of Β-galactosidase activity, suggesting that mutants are being selected in vivo. The potential advantages of live vaccines over killed vaccines are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175221
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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