Uptake and biological responses in land snail Cornu aspersum exposed to vaporized CdCl2.

The uptake of Cd and some biomarkers of exposure and effects have been investigated in specimens of land snail Cornu aspersum exposed to vaporized CdCl2 (10mg/L) for 7 days. The Cd levels quantified in snail's whole bodies confirmed Cd bioavailability trough vaporization and an higher accumulation in the midgut gland compared to the foot. Biological responses investigated showed a reduction of destabilization time of lysosomal membranes (NRRT) in hemocytes and an induction of catalase activities (CAT) in midgut gland. A further evidence of CdCl2 vaporized exposure was given by an increase in MT protein content as well as induction of Cd-MT gene expression, highlighting the central role of the midgut gland in Cd detoxification. These biomarkers can thus be considered as sensitive tools for the assessment of Cd contamination in the air using land snails as bioindicators. No changes in of GST activity and MDA were observed. From the overall results, the land snail, C. aspersum, could be used as good bioindicator of air quality for pollution monitoring purposes having shown clear signs of exposure and effects due Cd exposure by air.

Setting properties and in vitro bioactivity of strontium-enriched gelatin-calcium phosphate bone cements.

Strontium is known to reduce bone resorption and stimulate bone formation. We have investigated the effect of strontium on the setting properties and in vitro bioactivity of a biomimetic gelatin-calcium phosphate bone cement. Gelatin-alpha-TCP powders, with a gelatin content of 15 wt %, were prepared by grinding and sieving the solid compounds obtained by casting gelatin aqueous solutions containing alpha-TCP. 5 wt % of CaHPO(4).2H(2)O were added to the cement powders before mixing with the liquid phase, with a L/P ratio of 0.3 mL/g. Strontium was added as SrCl(2).6H(2)O in different amounts up to 5 atom %. X-ray diffraction analysis, mechanical tests, and SEM investigations were carried out on the cements after different times of soaking in physiological solution. The presence of strontium affects both the initial and the final setting times of the cements, which increase with the ion content. The microstructural modifications observed in the SEM micrographs of the fractured surfaces are in agreement with the increase of the total porosity, and with the slight reduction of the compressive strength of the aged cements, on increasing strontium content. The rate of transformation of alpha-TCP into calcium deficient hydroxyapatite increases on increasing strontium content. SEM reveals that MG63 osteoblasts grown on the cements show a normal morphology and biological tests demonstrate very good rate of proliferation and viability in every experimental time. In particular, strontium stimulates Alkaline Phosphatase activity, Collagen type I, osteocalcin, and osteoprotegerin expression.

Normal and osteopenic bone-derived osteoblast response to a biomimetic gelatin-calcium phosphate bone cement.

We have recently developed a new calcium phosphate bone cement enriched with gelatin (GEL-CP), which exhibits improved mechanical properties with respect to the control cement (C-CP). In a previous study, we demonstrated the good response of osteoblast-like cells to the new biomimetic bone cement. Herein, we extend the investigation to primary culture of osteoblasts derived from healthy and pathological bones. Osteoblasts derived from normal (N-OB) and osteopenic (O-OB) sheep bones were cultured on samples of GEL-CP, and their behavior was compared with that of cells cultured on C-CP as control. Cell morphology, proliferation, and differentiation were evaluated at 3 and 7 days. SEM analysis revealed that both N-OB and O-OB showed a normal morphology when cultured on GEL-CP. Biological tests demonstrated that the gelatin-enriched cement improves osteoblasts' activity and differentiation of O-OB cultures, with respect to the control samples. The data indicate that the new composite cement positively stimulates alkaline phosphatase activity, collagen type I, and osteocalcin production, not only in N-OB, but also in O-OB culture. The improvement due to the presence of gelatin suggests that the biomimetic composite material could be successfully applied as bone substitute also in the presence of osteopenic bone.

Human osteoblast response to pulsed laser deposited calcium phosphate coatings.

Octacalcium phosphate (OCP) and Mn(2+)-doped carbonate hydroxyapatite (Mn-CHA) thin films were deposited on pure, highly polished and chemically etched Ti substrates with pulsed laser deposition. The coatings exhibit different composition, crystallinity and morphology that might affect their osteoconductivity. Human osteoblasts were cultured on the surfaces of OCP and Mn-CHA thin films, and the cell attachment, proliferation and differentiation were evaluated up to 21 days. The cells showed a normal morphology and a very good rate of proliferation and viability in every experimental time. Alkaline phosphatase activity was always higher than the control and Ti groups. From days 7 to 21 collagen type I production was higher in comparison with control and Ti groups. The level of transforming growth factor beta 1 (TGF-beta1) was lower at 3 and 7 days, but reached the highest values during following experimental times (14 and 21 days). Our data demonstrate that both calcium phosphate coatings favour osteoblasts proliferation, activation of their metabolism and differentiation.

A biomimetic gelatin-calcium phosphate bone cement.

The interest in new bone substitutes is rapidly increasing in the field of orthopedic surgery. A variety of calcium phosphate bone cement has been developed and different additives have been used to improve their biocompatibility and bioactivity. Following a biomimetic strategy aimed at reproducing bone characteristics, this study investigates the biological properties of a new gelatin enriched calcium phosphate cement (GEL-CP) that exhibits improved mechanical properties with respect to cement prepared without gelatin (C-CP). Human osteoblast MG63 were cultured on the surfaces of GEL-CP and were compared to cells cultured on C-CP samples, and on polystyrene of plate culture as control (C). Cell attachment, proliferation and differentiation were evaluated up to 21 days. SEM revealed that osteoblasts grown on GEL-CP showed a normal morphology and biological tests demonstrated very good rate of proliferation and viability in every experimental time. The presence of gelatin stimulated alkaline phosphatase activity, collagen and transforming growth factor 31 production. The data indicate that the new cement GEL-CP favors osteoblast proliferation, activation of their metabolism and differentiation. The remarkable improvement of the setting properties of the calcium phosphate cement due to the presence of gelatin suggest that the biomimetic composite material could be successfully applied as bone substitute.