Browsing by Subject "Ultraestructure"

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    Ultrastructural study of the osteointegration of bioceramics (Whitlockite and Composite β-TCP + Collagen) in rabbit bone
    (Taylor and Francis, 1996) Vicente, V.; Meseguer, L.; Martínez Díaz, F.; Galián, A.; Rodríguez, J.; Alcaráz, M.; Clavel, M.; Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica
    Study examines the osteointegration of two porous ceramic implants, β-tricalcium phosphate (β-TCP) and a composite (β-TCP-collagen), in femur and tibias of 20 New Zealand white rabbits, which were sacrificed 1 week and 1, 4, and 12 months postimplant so that radiological, optical microscopic, and ultrastructural studies could be carried out. The results show a progressive degradation and resorption of both implant materials by means of a macrophagic reaction, which is at its most intense 1 month postimplant. The materials are substituted by newly formed bone tissue starting at the host bone-implant interface, the substitution being almost total by the end of the study, although less completely and earlier than in the case of the composite. Both materials can be considered as potential substitutes for bone tissue since they are biocompatible, bioreabsorbable, and osteogenic.
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    Ultrastructure of the mycorrhiza formed by Tetraclinis articulata (Vahl) Masters (Cupressaceae)
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 2004) Honrubia García, Mario; Morte Gómez, María Asunción; Biología Vegetal; Facultad de Biología
    The structural organisation of the endomycorrhiza in naturally infected seedlings and micropropagated and Glomus inoculated plants of Te- traclinis articulata was studied by means of light and electron micros- copy. Hyphal spread from cell to cell in the host root was entirely inter- cellular. Intracellular hyphae crossing through the host walls were ne- ver observed. This could be favoured by the presence of numerous wall swellings at the contacting area among cell walls which are cha- racteristic of T. articulata roots. These wall swellings could impede the crossing of the hyphae. The reduced interfacial region between both symbionts was observed with a fibrillar material in contact with the hyphal wall and, in some cases, in contact with the host plamalemma, although sometimes this region was occupied by small vesicles. The increase of the cytoplasmic organules both in the host cell and intrace- llular hyphae, during the arbuscular phase, indicated an increase of the metabolic activity of both symbionts. The membrane formations, gene- rally referred to as plasmalemmasomes, appeared in the arbuscular interfacial zone and in the cytoplasm of the arbuscular hyphae. This is a typical arbuscular mycorrhiza.