Papers by Author: M. Fatima Leite

Abstract: Fifteen different lithium-hydroxyapatite composites were tested in this work. LiHA were prepared using 0.25 %, 1 % and 2 % of lithium and five different sintering temperature 900, 1000, 1100, 1200 and 1300oC. Primary culture of osteoblasts were used to evaluate the biocompatibility of the samples, concerning to cell viability and alkaline phosphatase production. The 1% LiHA samples sintered at 1100, 1200 and 13000C showed the best results.

Abstract: The in vitro biocompatibility of aragonite material obtained from inner and out layers of four different molluscs was tested. After grinding and sieving, the obtained fine powders were put in contact with primary osteoblasts derived from rat calvariae. The viability of the cells increased at about 10% in the presence of powders derived from Vennus Gallina outer layer and from Pecten Jacobaeus inner layer. In the case of the presence of the other 6 tested powders, there was no statistical difference in cells’ viability. With regard to alkaline phosphatase production, all the tested powders induced a decrease of the production of this enzyme by osteoblasts. There was no evidence of any alterations in collagen production.

Abstract: In the current work, we investigated cellular viability, proliferation, and metabolic activity of rat primary culture osteoblasts in contact with a sample of collagen type I (C) and of this same collagen chemically treated (CTP). The chemical process used here consisted in recover the collagen surface with silica glass obtained from a sol-gel process. The cell viability, the cell death, the alkaline phosphate production and collagen secretion, after 72 hours of incubating the samples with osteoblasts, were measured by MTT assay, propidium iodide, NBT-BCIP assay and SIRCOL method, respectively. The viability and proliferation of osteoblasts had a significant decrease in the presence of samples when compared to control. The alkaline phosphatase production by the cells had a significant increase in the presence of CTP and collagen secretion by the cells was practically the same when compared to control.

Abstract: Samples of zirconia and a bioinert SiO2-containing glass with different surface roughness were immersed into human whole blood for different settling times to investigate the adhesion and attachment of blood cells onto these materials. The cell/material interface was directly observed by scanning electron microscopy (SEM). The results indicate that the blood cells preserved their physiology and attaching capability regardless the type of material, surface roughness, and settling time. The SEM images strongly indicate the normal function of adhesion proteins.

Abstract: Titanium reinforced with hydroxyapatite (TiHA) prepared using 15% of titanium and 3 different sinterizing temperatures 1100, 1200 and 1300 oC showed a significant increase in cell proliferation, when compared to the control.

Abstract: Two (45.5 wt % P2O5, 54.5 wt% CaO) and three (45 wt % P2O5, 28 wt% CaO, 27wt% Na2O) oxide glasses, sinterizing at 1200 and 1300oC[2] showed an increase on cell viability and proliferation.

Abstract: The biocompatibility of Zeolite was evaluated, in vitro, compared to a control and to three different biomaterials: hydroxyapatite from bovine bone, calcium phosphate and a commercial eugenol paste. The Zeolite did not affect cellular proliferation neither the alkaline phosphatase and collagen production. The apoptosis index of the zeolite groups were similar to control and optical microscopy observations did not show any morphological cell change, except the some cytoplasmatic vacuole formation.

Abstract: Osteoblasts constitutively release glutamate and this release appears to be regulated by calcium entry. In this work we investigated if the bioactive glass with 60% of silicon (BG60S) could alter glutamate release by osteoblasts. We demonstrated that osteoblasts incubated with medium containing ionic products from the dissolution of BG60S showed lower release of glutamate when compared to control. Since intracellular calcium (Cai 2+) increase is required for glutamate release we investigated the subcellular distribution of the calcium channel inositol triphosphate receptors (InsP3Rs) in the presence of BG60S compared to control. We found that the type-III InsP3R was not expressed in osteoblast, while the type-II InsP3R was expressed mainly in the cytosol. We also found that the expression of type-II InsP3R decreased in BG60S treated osteoblasts compared to control. On the other hand, we found that the type-I InsP3R was expressed mainly in the nucleus and its expression increased in the presence of the biomaterial.