Mise en évidence d'un agent coagulant utilisable en fromagerie dans les fruits de Balanites aegyptiaca

Study of a Suitable Cheese Making Milk-clotting Agent from Balanites aegyptiaca Fruits. As slaughtering of zebu (Bos indicus) calves in Cameroon is forbidden, calf abomasa are rare on markets so it is diffi cult to prepare rennet. The aim of this study was to look for other sources of milk clotting extracts, especially from Balanites aegyptiaca fruits. B. aegyptiaca is a widespread tree in northern Cameroon. Its fruit is pulpy with a thin and hard epicarp, a dark brown mesocarp and a hard endocarp enclosing an oil seed. The fruits of B. aegyptiaca were harvested at Pitoa (9°23' N, 13°32 E). Milk clotting, determined by the Berridge method, was only obtained with mesocarp extracts. The experimental design of the extraction was a split-plot (5 4 4) with 5 mesocarp concentrations, 4 temperatures and 4 maceration times. Optimum extraction was performed when macerating 50 g mesocarp in 100 ml water at 4 °C during 9 h. Protein content (91 14 mg. ml-1) was determined by bicinchoninic acid assay. Five proteins of respective molecular masses 27, 30, 42, 44 and 90 kg.mole-1 were observed by SDS-PAGE under reducing conditions. The force of the extract was determined by comparing its milk clotting time to that obtained with rennet. Proteolytic activity of the extract was measured by hydrolysis of bovine haemoglobin and titration of free NH2 using l'ophthaldialdehyde reagent. Counting of coliforms was carried out on DCL gelose, that of the total aerobic mesophil fl ora on PCA and that of the sulfi to-reducing fl ora on TSN. The extract only contained coliforms and aerobic mesophil fl ora. Fresh cheese was made with zebu milk using rennet or B. aegyptiaca mesocarp extract. Indemnes of Specifi que Pathogen Organism mice were fed with these cheeses then with crude B. aegyptiaca mesocarp extract. No abnormality, nor toxicity were observed on mice. A panel was allowed to appreciate these cheeses. Statistical analysis was conducted using SASsoftware. It was concluded that B. aegyptiaca mesocarp extract is suitable for cheese manufacture

The behavior of osteoblast-like cells on various substrates with functional blocking of integrin-β1 and integrin-β3

This study was designed to examine the influence of integrin subunit-β1 and subunit-β3 on the behavior of primary osteoblast-like cells, cultured on calcium phosphate (CaP)-coated and non coated titanium (Ti). Osteoblast-like cells were incubated with specific monoclonal antibodies against integrin-β1 and integrin-β3 to block the integrin function. Subsequently, cells were seeded on Ti discs, either non coated or provided with a 2 μm carbonated hydroxyapatite coating using Electrostatic Spray Deposition. Results showed that on CaP coatings, cellular attachment was decreased after a pre-treatment with either anti-integrin-β1 or anti-integrin-β3 antibodies. On Ti, cell adhesion was only slightly affected after a pre-treatment with anti-integrin-β3 antibodies. Scanning electron microscopy showed that on both types of substrate, cellular morphology was not changed after a pre-treatment with either antibody. With quantitative PCR, it was shown for both substrates that mRNA expression of integrin-β1 was increased after a pre-treatment with either anti-integrin-β1 or anti-integrin-β3 antibodies. Furthermore, after a pre-treatment with either antibody, mRNA expression of integrin-β3 and ALP was decreased, on both types of substrate. In conclusion, osteoblast-like cells have the ability to compensate to great extent for the blocking strategy as applied here. Still, integrin-β1 and β3 seem to play different roles in attachment, proliferation, and differentiation of osteoblast-like cells, and responses on CaP-coated substrates differ to non coated Ti. Furthermore, the influence on ALP expression suggests involvement of both integrin subunits in signal transduction for cellular differentiation

Bone Tissue Response to Porous and Functionalized Titanium and Silica Based Coatings

Background: Topography and presence of bio-mimetic coatings are known to improve osseointegration. The objective of this study was to evaluate the bone regeneration potential of porous and osteogenic coatings. Methodology: Six-implants [Control (CTR); porous titanium coatings (T1, T2); thickened titanium (Ti) dioxide layer (TiO2); Amorphous Microporous Silica (AMS) and Bio-active Glass (BAG)] were implanted randomly in tibiae of 20-New Zealand white rabbits. The animals were sacrificed after 2 or 4 weeks. The samples were analyzed histologically and histomorphometrically. In the initial bone-free areas (bone regeneration areas (BRAs)), the bone area fraction (BAF) was evaluated in the whole cavity (500 mm, BAF-500), in the implant vicinity (100 mm, BAF-100) and further away (100–500 mm, BAF-400) from the implant. Bone-to-implant contact (BIC-BAA) was measured in the areas where the implants were installed in contact to the host bone (bone adaptation areas (BAAs)) to understand and compare the bone adaptation. Mixed models were used for statistical analysis. Principal Findings: After 2 weeks, the differences in BAF-500 for different surfaces were not significant (p.0.05). After 4 weeks, a higher BAF-500 was observed for BAG than CTR. BAF-100 for AMS was higher than BAG and BAF-400 for BAG was higher than CTR and AMS. For T1 and AMS, the bone regeneration was faster in the 100-mm compared to the 400-mm zone. BIC-BAA for AMS and BAG was lower after 4 than 2 weeks. After 4 weeks, BIC-BAA for BAG was lower than AMS and CTR. Conclusions: BAG is highly osteogenic at a distance from the implant. The porous titanium coatings didn’t stimulate bone regeneration but allowed bone growth into the pores. Although AMS didn’t stimulate higher bone response, it has a potential of faster bone growth in the vicinity compared to further away from the surface. BIC-BAA data were inconclusive to understand the bone adaptation.status: publishe

Surface Modification of Biomedical and Dental Implants and the Processes of Inflammation, Wound Healing and Bone Formation

Bone adaptation or integration of an implant is characterized by a series of biological reactions that start with bone turnover at the interface (a process of localized necrosis), followed by rapid repair. The wound healing response is guided by a complex activation of macrophages leading to tissue turnover and new osteoblast differentiation on the implant surface. The complex role of implant surface topography and impact on healing response plays a role in biological criteria that can guide the design and development of future tissue-implant surface interfaces

The influence of implant surface characteristics on bone response

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Ce mémoire a pour sujet la pédagogie de projet en réponse aux besoins éducatifs particuliers d'élèves de CLIS 1. Il s'agit de montrer comment la pédagogie de projet peut répondre aux besoins mnésiques, métacognitifs et aux besoins liés au sentiment de compétences dans le domaine de laproduction d'écrits. Au terme de cette étude, la pédagogie apparaît comme pouvant être une réponse adaptée aux besoins éducatifs mais ne peut se suffire à elle-même