Browsing by Author "Abiraman, S"

Now showing 1 - 4 of 4
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    Bone growth response with porous hydroxyapatite granules in a critical sized lapine tibial-defect model
    (Bulletin of Materials Science., 2002) John, A; Abiraman, S; Varma, HK; Kumar, TV; Umashankar, PR
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    Fibrin glue as an osteoinductive protein in a mouse model
    (BIOMATERIALS, 2002)
    Fibrin sealant or fibrin glue (FG) has been found to be effective as a wound-healing substance in surgery. However, its role in bone fracture healing and osseous tissue response is not fully understood. This ambiguity questions the potential of FG as an inductive protein. The present study was undertaken to evaluate the osteoinductive property of FG when coated with calcium phosphate and glass ceramics and implanted in the extraskeletal site of male Swiss albino mice. Implant materials used for this study were hydroxyapatite (HA) porous granules (300-350 mum), bioactive glass system (BGS)-AW type and calcium phosphate calcium silicate system (HABGS) non-porous granules (300-350 mum). Uncoated granules (control) and coated granules with 2.5 mg FG and 5 mg FG were implanted in the quadriceps muscle of mice and sacrificed after 28 days. Histologically, HA, BGS and HABGS implanted animal groups showed good healing response. However, neo-osteogenesis was observed only in the BGS and HABGS granules impregnated with FG. Furthermore, bone formation was observed to be more conspicuous in 5 mg FG coated BGS and HABGS granules when compared with 2.5 mg FG coated BGS and HABGS granules. Fluorochrome labeling proved that mineralization had already started by day 15 with FG preadsorbed BGS and HABGS granules. On the contrary, the uncoated granules did not show any de novo bone formation. This experimental study provides an evidence of the positive role of FG as a potential osteoinductive biologic tissue adhesive. (C) 2002 Elsevier Science Ltd. All rights reserved.
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    Preliminary in vitro and in vivo characterization of a sol-gel derived bioactive glass
    (Bulletin of Materials Science., 2002) Abiraman, S; Varma, HK; Kumari, TV; Umashankar, PR; John, A
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    Preliminary in vitro and in vivo characterizations of a sol-gel derived bioactive glass-ceramic system
    (BULLETIN OF MATERIALS SCIENCE, 2002) Abiraman, S; Varma, HK; Kumari, TV; Umashankar, PR; John, A
    This study investigates quantitatively and qualitatively the sol-gel derived bioactive glass-ceramic system (BGS)-apatite-wollastonite (AW) type granules in the size range of 0.5-1 mm, as an effective graft material for bone augmentation and restoration. Scanning electron micrographs (SEM) of the sintered granules revealed the rough material surface with micropores in the range 10-30 mum. X-ray diffraction (XRD) pattern of the granules revealed the presence of crystalline phases of the hydroxyapatite and wollastonite, and the functional groups of the silicate and phosphates were identified by Fourier transform infrared spectroscopy (FT-IR). The in vitro cell culture studies with L929 mouse fibroblast cell line showed very few cells adhered on the BGS disc after 24 h. This could be due to the highly reactive surface of the disc concomitant with the crystallization but not due to the cytotoxicity of the material, since the cellular viability (MTT assay) with the material was 80%. Cytotoxicity and cytocompatibility studies proved that the material was non-toxic and biocompatible. After 12 weeks of implantation of the BGS granules in the tibia bone of New Zealand white rabbits, the granules were found to be well osteointegrated, as observed in the radiographs. Angiogram with barium sulphate and Indian ink after 12 weeks showed the presence of micro capillaries in the vicinity of the implant site implicating high vascularity. Gross observation of the implant site did not show any inflammation or necrosis. SEM of the implanted site after 24 weeks revealed good osteointegration of the material with the newly formed bone and host bone. New bone was also observed within the material, which was degrading. Histological evaluation of the bone healing with the BGS granules in the tibial defect at all time intervals was without inflammation or fibrous tissue encapsulation. After 2 weeks the new bone was observed as a trabeculae network around the granules, and by 6 weeks the defect was completely closed with immature woven bone. By 12 weeks mature woven bone was observed, and new immature woven bone was seen within the cracks of the granules. After 24 weeks the defect was completely healed with lamellar bone and the size of the granules decreased. Histomorphometrically the area percentage of new bone formed was 67.77% after 12 weeks and 63.37% after 24 weeks. Less bone formation after 24 weeks was due to an increased implant surface area contributed by the material degradation and active bone remodeling. The osteostimulative and osteoconductive potential of the BGS granules was established by tetracycline labelling of the mineralizing areas by 2 and 6 weeks. This sol-gel derived BGS granules proved to be bioactive and resorbable which in turn encouraged active bone formation.