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At least 433 records · Page 24Linked to original sources
PubMed2006

Anomalous ionic conductivity increase in Li2S + GeS2 + GeO2 glasses.

Numerous studies of the ionic conductivities in oxide-doped chalcogenaide glasses have shown the anomalous result that the ionic conductivity actually increases significantly (by more than a factor of 10 in some cases) by the initial addition of an oxide phase to a pure sulfide glass. After this initial sharp increase, the conductivity then monotonically decreases with further oxide addition. While this behavior is important to the application of these glasses for Li batteries, no definitive understanding of this behavior has been elucidated. To examine this effect further and more completely, the ionic conductivities of 0.5Li(2)S + 0.5[(1 - x)GeS(2) + xGeO(2)] glasses have been measured on disc-type bulk glasses. The ionic conductivity of the 0.5Li(2)S + 0.5GeS(2) (x = 0) glass was observed to increase from 4.3 x 10(-5) (Omega cm)(-1) to 1.5 x 10(-4) (Omega cm)(-1) while the activation energy decreased to 0.358 eV from 0.385 eV by the addition of 5 mol % of GeO(2). Further addition of GeO(2) monotonically decreased the conductivity and increased the activation energy. On the basis of our previous studies of the structure of this glass system, the Anderson and Stuart model was applied to explain the decrease in the activation energy and increase in the conductivity. It is suggested that the "doorway" radius between adjacent cation sites increases slightly (from approximately 0.29(+/-0.05) A to approximately 0.40(+/-0.05) A) with the addition of oxygen to the glass and is proposed to be the major cause in decreasing the activation energy and thereby increasing the conductivity. Further addition of oxides appears to contract the glass structure (and the doorway radius) leading to an increase in the conductivity activation energy and a decrease in the conductivity.

Journal Article↗
PubMed2001

Evaluation of effect of 3D video glasses on perceived pain and unpleasantness induced by restorative dental treatment.

Previous studies on modulation of anxiety, pain and unpleasantness have documented a positive effect of video glasses (I-Glasses, Virtual i-O, Seattle, USA) on the perceived pain and unpleasantness under different laboratory and clinical conditions. The aim of this study was to evaluate whether distraction induced by video glasses also had an effect on the perceived intensity of pain and unpleasantness during dental treatment. Pain and unpleasantness was evoked by the preparation (drilling) of a minor dental cavity (class I). Twenty-three patients (17 female and six male, age range 20-49 years) with a need for an occlusal dental restoration in two homologous teeth participated in the study. In this split-mouth design, the patient received the dental treatment wearing 3D video glasses and without video glasses (control situation) in a randomized order. The tooth cavities were prepared in accordance with conventional techniques after mounting the video glasses. The patient rated the intensity of pain and unpleasantness on 100 mm visual analogue scales (VASs) after preparation of the first cavity; immediately after, the opposite tooth was prepared and again the volunteer rated the intensity of pain and unpleasantness. The cavities were then filled using a routine composite technique. Eventually, the patient indicated whether she would prefer video glasses or not if she were to have another filling and what the expectations of the effect had been. Differences in VAS ratings in the video and control situation were tested by Student's t-test. There was no statistically significant effect on the perceived pain (p=0.90) or unpleasantness (p=0.39), but the majority (74%) of the patients would still prefer to wear video glasses if they were to have another dental filling, and 73% had expected a positive effect of the video glasses. These findings suggest that perceived intensity of dental pain is resistant to a simple distraction technique.

Adult↗
PubMed2004

Dopant distribution in a Tm(3+)-Yb(3+) codoped silica based glass ceramic: an infrared-laser induced upconversion study.

The optically active dopant distribution in a Tm(3+)-Yb(3+) doped silica based glass ceramic sample has been investigated. A systematic analysis of the upconversion fluorescence of the Tm(3+)-Yb(3+) codoped glass and glass ceramic has been performed at room temperature. Tm(3+) and Yb(3+) single doped glass and glass ceramics have also been included in the study. Upon infrared excitation at 790 nm into the (3)H(4) level of the Tm(3+) ions a blue upconversion emission is observed, which is drastically increased in the Yb(3+) codoped samples. A rate equation model confirmed the energy transfer upconversion mechanism. Based on these results, the temporal dynamic curves of the levels involved in the upconversion process, (3)H(4), (2)F(5/2), and (1)G(4) were interpreted in the glass ceramic samples. The contribution of the optically active Tm(3+) and Yb(3+) ions in the crystalline and in the vitreous phase of the glass ceramic was distinguished and the ratio of Tm(3+) ions in the crystalline phase could be quantified for the 1 mol % Tm(3+)-2.5 mol % Yb(3+) glass ceramic. A surprising result was obtained for that concentration: the main contribution to the upconversion emission of the glass ceramic is due to Tm(3+)-Yb(3+) ions in the vitreous phase.

Journal Article↗
PubMedDate not supplied

Ground-glass attenuation in nodular bronchioloalveolar carcinoma: CT patterns and prognostic value.

PURPOSE: The purpose of our study was to assess the CT patterns and prognostic value of ground-glass attenuation in nodular bronchioloalveolar carcinoma (BAC). METHOD: We retrospectively reviewed CT examinations of 22 patients with 24 nodular BACs who underwent surgery. CT and pathologic findings were analyzed and correlated with postoperative course of disease. RESULTS: We detected five patterns of ground-glass attenuation associated with nodular BAC: pure ground-glass nodule (n = 1), ground-glass nodule with superimposed lymphangitis (n = 1), nodule with mixed areas of ground-glass attenuation and consolidation (n = 2), ground-glass halo around nodule (halo sign) (n = 3), and nodule associated with a plurisegmental area of ground-glass attenuation (n = 1). Two patients with the halo sign and a third patient with a plurisegmental area of ground-glass attenuation rapidly developed diffuse pulmonary disease by bronchogenic spread and died a few months after surgery. CONCLUSION: Our series demonstrates that focal BAC may progress to diffuse pulmonary involvement by bronchogenic spread. The presence of a large area of ground-glass attenuation associated with a nodular BAC might be the CT sign of an aggressive biologic behavior. In these cases there is a high likelihood for diffuse disease to develop from bronchogenic spread.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1991

Glass encodes a site-specific DNA-binding protein that is regulated in response to positional signals in the developing Drosophila eye.

The glass gene encodes a zinc finger protein required for normal photoreceptor cell development in Drosophila. We show that glass transcripts are present in the third-instar eye-imaginal disc starting in the morphogenetic furrow and extending to the posterior margin of the disc; glass protein is detected in the nuclei of all cells in this region. We also show that glass encodes a site-specific DNA-binding protein. A 27-bp glass-binding site can confer glass-dependent expression on a reporter gene in developing photoreceptor cells, the particular subset of glass-expressing cells known to require glass function. This specificity may represent a regulation of glass protein activity after cells are recruited to the photoreceptor cell fate.

Animals↗
PubMed2005

Glass-batch composition monitoring by laser-induced breakdown spectroscopy.

Laser-induced breakdown spectroscopy is an almost ideal technique for the in situ monitoring of the composition of a glass batch before it enters the glass-melting furnace, saving a significant amount of energy by the optimization of the furnace parameters for a particular composition of the glass batch. We investigate this application of laser-induced breakdown spectroscopy by determining the elemental composition of the glass batch used (i) as a surrogate for radioactive glass waste and (ii) to manufacture the most common type of flat glass. The surrogate glass-batch and flat-glass calibration curves for the major constituents have been prepared using both the line intensity and the line-intensity ratio. The analytical figure of merit of the glass-batch data obtained from the two different detection systems, namely, the Czerny-Turner spectrometer with an intensified diode-array detector and the echelle spectrometer fitted with an intensified CCD camera, are compared.

Journal Article↗
PubMed2003

Widespread ground-glass opacity of the lung in consecutive patients undergoing CT: Does lobular distribution assist diagnosis?

OBJECTIVE: Our purpose was to establish the most frequent diagnoses associated with widespread ground-glass opacity on CT and to determine if the distribution of ground-glass opacity at a lobular level affects the likelihood of a given diagnosis. MATERIALS AND METHODS: A retrospective search of our department's CT database from January 1998 through December 2000 revealed 153 cases of ground-glass opacity. Patients evaluated using bronchoscopy or open biopsy within 30 days (mean, 6.9 days) of imaging with ground-glass opacity as the predominant high-resolution CT finding were selected. There were 21 men and 16 women with a mean age of 51.4 years. Two chest radiologists, unaware of the clinical diagnoses, independently recorded lobular distributions. Consensus interpretation was used for discrepancies. Primary distributions were recorded as lobular (geographic ground-glass opacity marginated by septal anatomy), centrilobular (ground-glass opacity related to bronchovascular anatomy), or random. RESULTS: Infectious and other histologic diagnoses fell into four diagnostic groups: atypical pneumonia, chronic infiltrative interstitial disease, acute air-space filling, and drug toxicity. Ground-glass opacity was most frequently associated with acute atypical pneumonia (n = 12, 32%), chronic infiltrative disease (n = 10, 27%), acute air-space filling (n = 6, 16%), and drug toxicity (n = 4, 11%). In five patients, a definitive diagnosis was not established. Ground-glass opacity was most commonly randomly distributed (n = 16, 43%), followed by lobular (n = 15, 41%) and centrilobular (n = 6, 16%) distributions. Distribution did not correlate with diagnostic group. CONCLUSION: In unselected cases of ground-glass opacity evaluated at a tertiary institution, atypical infection and chronic infiltrative interstitial disease accounted for 59% of diagnoses. Distribution at a lobular level did not differentiate underlying causes.

Adult↗
PubMed2005

Effect of water storage, thermocycling, the incorporation and site of placement of glass-fibers on the flexural strength of veneering composite.

OBJECTIVES: To evaluate the effects of water storage, thermocycling, and the incorporation of glass-fibers, on the flexural strength of veneering composites. METHODS: Veneering composites with different fillers, matrices and polymerization methods (Belleglass Kerr Inc., Orange, CA, USA; Sculpture, Pentron Inc. Wallingford CT, USA; Sinfony, 3M Espe, Seefeld, Germany; SR Adoro LC and HP, Targis, Ivoclar Vivadent, Schaan, Liechtenstein), a glass-fiber framework material (Vectris Pontic VP, Ivoclar Vivadent) and a direct restorative composite control (Tetric Ceram, Ivoclar Vivadent) were selected. For the first part of the study, 30 bar specimens (25 x 2 x 2 mm3) per material were fabricated. Ten were stored for 24 h and 10 for 14 days in water at 37 degrees C. Ten were thermocycled (3000 x; 5-50-5 degrees C). Three-point bending tests (crosshead speed: 0.5 mm/min) were performed. For the second part of the study, all veneering materials were combined with a glass-fiber framework (VP). Sixty specimens were produced for each material (25 x 4 x 2 mm3) and treated as in the first part. Three-point bend tests were performed with the reinforcing glass-fiber framework either on the tension or the compression side. Data was evaluated by ANOVA and Weibull analysis. RESULTS: A decrease in flexural strength was observed after water storage or thermocycling for all veneering materials tested. None of the tested materials exhibited significant advantages compared to the control. The flexural strength of glass-fiber reinforced frameworks was ten times higher and not influenced by water storage or thermocycling. A significant reinforcing effect from glass fibers was observed when they were placed on the tension but not when placed on the compression side. SIGNIFICANCE: A glass-fiber framework on the tension side significantly improved the flexural strength of veneering composites. There was less deterioration due to water storage and thermocycling with the glass-fiber reinforced veneering composite compared to the non-reinforced materials.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1996

Mechanical properties of glass ionomers under static and dynamic loading.

OBJECTIVES: This study evaluated the mechanical properties under static and cyclic loading conditions of various types of glass ionomers used for bases and core build-ups under restorations. METHODS: Compressive strength and three-point flexural strength of two different glass ionomers and two metal-reinforced glass ionomers were determined 1 d after the start of mixing. The flexural fatigue resistance of these materials was measured in the load range of 650 g to 1050 g using a three-point bending machine, and fractured surfaces of the specimens were examined using SEM. RESULTS: All the glass ionomers exhibited similar compressive and flexural strengths. The results analyzed by Cox' proportional hazard model demonstrated that the admixed-type metal-reinforced glass ionomer had the highest fatigue resistance, while the water-hardening glass ionomer had the lowest fatigue resistance among the materials examined (p<0.5). SIGNIFICANCE: There was no significant improvement in the static mechanical properties from incorporating metal particles into the glass ionomers. However, the addition of metal particles as in the admixed-type metal-reinforced glass ionomer produced a material with increased fatigue resistance.

Cermet Cements↗
PubMed1998

Effect of surface reaction stage on fibronectin-mediated adhesion of osteoblast-like cells to bioactive glass.

Bioactive glasses and ceramics enhance bone formation and bond directly to bone, and have emerged as promising substrates for bone tissue engineering applications. Bone bioactivity involves physicochemical surface reactions and cellular events, including cell attachment to adsorbed extracellular matrix proteins. The effects of fibronectin (Fn) adsorption and glass surface reaction stage on the attachment of osteoblast-like cells (ROS 17/2.8) to bioactive glass were analyzed. Bioactive glass disks were pretreated in a simulated physiologic solution to produce three reaction layers: unreacted glass (BG0), amorphous calcium phosphate (BG1d), and carbonated hydroxyapatite (BG7d). Synthetic hydroxyapatite (sHA) and nonreactive borosilicate glass (CG) were used as controls. A spinning disk device which applied a linear range of forces to attached cells while maintaining uniform chemical conditions at the interface was used to quantify cell adhesion. The number of adherent cells decreased in a sigmoidal fashion with applied force, and the resulting detachment profile provided measurements of adhesion strength. For the same amount of adsorbed Fn, cell adhesion was higher on surface-reacted bioactive glasses (BG1d and BG7d) than on BG0, CG, and sHA. For all substrates, cell attachment was primarily mediated by the RGD binding site of Fn, as demonstrated by blocking experiments with antibodies and RGD peptides. Cell adhesion strength increased linearly with adsorbed Fn surface density. Analysis of this fundamental relationship revealed that improved adhesion to reacted bioactive glasses resulted from enhanced cell receptor-Fn interactions, suggesting substrate-dependent conformational changes in the adsorbed Fn.

Biocompatible Materials↗
PubMed1993

An experimental study and clinical pilot trials on yttrium-90 glass microspheres through the hepatic artery for treatment of primary liver cancer.

BACKGROUND: Yttrium-90 (90-Y) glass microsphere is a new kind of radiation microsphere for internal radiation therapy of primary liver cancer (PLC). The study was carried out by administration of 35 microns nondegradable 90-Y glass microsphere through the hepatic artery for treatment of PLC. METHODS: Six rabbits were injected with 185-1480 megabecquerels (MBq) of 90-Y glass microspheres, and three rabbits were injected with 35-300 mg of 89-Y glass microspheres for the toxic test. Eighteen patients received 2442-5550 MBq of 90-Y glass microspheres for the treatment of PLC. Whole blood counts, liver function, and imaging examination were performed. Pathologic examinations were performed on all rabbits. RESULTS: All rabbits were apparently well after absorbing 114.1-845.2 Gy 90-Y glass microspheres in the liver but showed transient degeneration of hepatocytes and portal fibrosis histologically. The mean absorbed dose in liver tissue of patients with PLC was 30.33 Gy, whereas that in tumor tissue was 88 Gy and the highest in tumor tissue, 186.36 Gy. The mean tumor:liver tissue ratio was 3:1; the highest, 14:1. Fourteen patients were still alive after half a year's follow-up and 6 of these 14 were still alive after 1 year. CONCLUSIONS: The rabbits could tolerate up to eight-fold of the upper limit of clinical dose (100 Gy). Good responses to the radiation therapy of 90-Y glass microspheres in patients with localized and hypervascular or vascular mass were achieved. Contraindications for the therapy were presence of massive hepatic arterioportal shunt and cancer emboli in the main portal vein. It is safe and applicable to deliver 90-Y glass microspheres in large doses through the hepatic artery for internal radiation treatment of PLC.

Adult↗
PubMed2004

Microfluidic devices obtained by thermal toner transferring on glass substrate.

A new process for the manufacture of microfluidic devices based on deposition of laser-printing toner on glass substrates is described. It is an alternative method to the toner on polyester film (toner-polyester) one, previously introduced. Commercial laser printers cannot print directly on glass, thus the toner must first be printed on a special paper and then transferred by heating under pressure to the glass surface. Although this procedure is more complex than the toner-polyester one, it can be repeated several times, yielding multiple toner layers. Even without special alignment equipment, up to four layers could be satisfactorily piled up. Characterization tests revealed that the toner-glass devices have similar behavior as toner-polyester ones regarding the toner layer porosity. The main advantages of the toner-glass technology are improved mechanical stability, possibility of multiple toner layers, augmented electroosmotic flow (EOF), and improved heat transfer. On the other hand, toner adhesion to glass is weaker than to polyester, which limits the device lifetime and usable liquid media. The measured EOF mobility (3.5 x 10(-4) cm2.V(-1).s(-1) for pH 7) suggests that it is mainly determined by the glass surface, being little influenced by the toner walls. Microchip electrophoresis with contactless conductivity detection and photometric detection were implemented using toner-glass devices.

Electrophoresis, Microchip↗
PubMed2002

Synthesis, degradation, and in vitro cell responses of sodium phosphate glasses for craniofacial bone repair.

This report outlines the initial synthesis, degradation, and short-term biocompatibility of sodium phosphate glasses, for use in the drawing of fibers and manufacture of biodegradable composites. Biocompatibility studies were performed using a macrophage cell line and primary human craniofacial osteoblasts. Sodium hydrogen phosphate and sodium dihydrogen phosphate glass synthesized for less than 1 h, resulted in a higher degradation rate than glass synthesized for 3 h or more (0.015 mg cm(-2) h(-1)). Glasses with high and low ratios of hydrogen phosphate to dihydrogen phosphate had very similar degradation rates. A condensation route for the formation of the glass should give rise to varying degradation rates with varying ratios of starting materials. It is suggested that the degradation rate of the glass is independent of the concentrations of the initial reagents and that ring-opening polymerization, which reaches an equilibrium state, occurs. Biocompatibility studies suggest minimal macrophage activation (low levels of peroxide and interleukin-1beta release and rounded morphology) and high osteoblast biocompatibility. The ultimate aim of our studies is to produce a biocompatible soluble phosphate glass that can be drawn into fibers for incorporation into a polycaprolactone matrix for craniofacial bone repair. This report demonstrates the successful production of a soluble glass, which is biocompatible with regard to osteoblasts and macrophages. Recent data from our laboratory have demonstrated successful fiber drawing and production of a novel polycaprolactone.

Absorbable Implants↗
PubMed2002

PMMA-based bioactive cement: effect of glass bead filler content and histological change with time.

A new bioactive bone cement (designated GBC), which is a polymethyl methacrylate (PMMA)-based composite consisting of bioactive glass beads as an inorganic filler and high molecular-weight PMMA as an organic matrix, has been developed. The purpose of the present study was to evaluate the effect of the filler content on the mechanical properties and osteoconductivity of GBC, to decide the most suitable filler proportion, and to evaluate the degree of cement degradation with time. The bioactive beads, consisting of MgO-CaO-SiO(2)-P(2)O(5)-CaF(2) glass, were added to the cement in various proportions (40-70 wt %). The bending strength of GBC did not differ among the proportions (approximately 136 MPa), but the elastic modulus of bending of GBC increased as the glass bead filler content increased (approximately 4.1-7.2 GPa). The all types of GBC were packed into the intramedullary canals of rat tibiae to evaluate osteoconductivity, as determined by an affinity index calculated as the length of bone in direct contact with the cement surface expressed as a percentage of the total length of the cement surface. Rats were sacrificed at 4, 8, 25, and 39 weeks after implantation, and the affinity index was calculated for each type of GBC at each time point. Histologically, new bone had formed along the surface of all types of GBC within 4 weeks, even in GBC containing only 40 wt % of glass beads. The affinity indices of GBC tended to increase as the proportion of glass bead filler increased and as the implantation period increased. In GBC containing 60 or 70 wt % of glass beads, significant rapid increases in the affinity indices were found from 4 to 8 weeks, and the high values (approximately 70%) were maintained up to 39 weeks. A sign of glass bead degradation was observed at the bone-cement interface in the rat tibiae at 39 weeks. We conclude that, when mechanical properties and osteoconductivity are both taken into consideration, GBC containing 60 or 70 wt % of glass beads is the most suitable formulation, but that further studies are needed to investigate and overcome the degradation.

Animals↗
PubMed1991

Bone-bonding ability of P2O5-free CaO.SiO2 glasses.

An apatite- and wollastonite-containing glass-ceramic (A.W-GC) has been reported to form a tight bond with living bone through an apatite layer formed on its surface. This layer is considered to be formed by dissolution of Ca2+ and HSiO3- ions from the glass-ceramic into the surrounding body fluids. In order to confirm this proposed mechanism for the surface reaction of A.W-GC, three kinds of glass in the systems CaO-SiO2, CaO-SiO2-CaF2, and CaO-SiO2-P2O5 were implanted into the tibiae of rabbits for 3 or 8 weeks. Contact microradiography and SEM-EPMA showed that all three kinds of glass formed a Ca,P-rich layer in combination with a Si-rich layer on their surfaces within 3 weeks and formed a direct bond with bone via these layers. The detaching test, performed 8 weeks after implantation, showed that the loads required to detach the implants from the bone were almost equal for the phosphorus-free and the phosphorus-containing glasses. It was concluded that even P2O5-free CaO.SiO2 glass formed a Ca,P-rich layer on its surface and bonded tightly with living bone. If glasses and glass-ceramics release at least Ca2+ and HSiO3- ions, this would be sufficient for them to form the Ca,P-rich layer on their surfaces in vivo, enabling them to bond directly with bone.

Animals↗
PubMed2004

Novel bioactive and biodegradable glass ceramics with high mechanical strength in the CaO--SiO2--B2O3 system.

Novel bioactive and biodegradable glass ceramics with high mechanical strength in the (50-x/2)CaO. SiO(2)--xB(2)O(3) (4.2 < or = x < or = 17.2) system were investigated. The systems consisted of three phases: monoclinic wollastonite, calcium metaborate, and amorphous borosilicate matrix. The glass ceramics containing 4.2 mol% and 8.4 mol% B(2)O(3) showed high bulk density and a dense microstructure. Mechanical strengths of the glass ceramics were higher than those of other bioactive ceramics: high compressive strength (2813 MPa), bending strength of 212 MPa, and fracture toughness of 3.12 MPa. m(1/2). The glass-ceramic formed apatite layer on their surface in the simulated body fluid and showed significant biodegradation. The degree of apatite formation in the glass ceramics depended on the calcium metaborate content and borosilicate glassy matrix. Additional calcium metaborate and borosilicate glassy matrix increased the apatite formation rate on the surface. It might be likely that calcium metaborate causes supersaturation of Ca ions, for its high solubility in SBF and the water-reactive borosilicate glassy matrix formed Sibond;OH groups on the surface to provide nucleation sites for apatite formation. Also, through in vitro test for the biocompatibility of the CaO--SiO(2)--B(2)O(3) glass ceramics, no cytotoxicity of the glass ceramics were found. The results on bioactivity and noncytotoxicity indicated that glass ceramics in the (50-x/2)CaO. SiO(2)--xB(2)O(3) (4.2 < or = x < or = 17.2) system could be useful as a biodegradable bone replacement material.

Biocompatible Materials↗
PubMed2004

Proliferation, differentiation, and calcification of preosteoblast-like MC3T3-E1 cells cultured onto noncrystalline calcium phosphate glass.

The purpose of this study was to investigate calcium phosphate glass as a potential biomaterial for hard tissue repair. We prepared calcium phosphate glass using the system CaO-CaF(2)-P(2)O(5)-MgO-ZnO and cultured MC3T3-E1 cells onto the glass in alpha-MEM with beta-glycerophosphatase and ascorbic acid. Proliferation of the cells was determined to evaluate the biocompatibility of the prepared calcium phosphate glass. The alkaline phosphatase activity was measured to examine the osteoblast differentiation. Mineralization was evaluated by staining the calcium precipitates with Alizarin red. Culture onto the calcium phosphate glass exhibited no significant influence on cell proliferation compared to the polystyrene chosen as a control in this experiment (p > 0.05). The alkaline phosphatase activity in the experimental group, however, was enhanced by the calcium phosphate glass significantly at 10-18 days after incubation than that of the control group (p < 0.05). The promotion of bone-like tissue formation by the calcium phosphate glass was observed after 7 days and thereafter. The results of the present study indicate that the prepared calcium phosphate glass affects osteogenesis by increasing calcification of the extracellular matrix.

Alkaline Phosphatase↗
PubMed2006

Effects of 58S sol-gel glasses on the temporal expression of bone markers during mouse osteoblastic differentiation.

Previous studies have shown that bioactive glasses can support osteoblastic growth and differentiation in vitro as well as in vivo. More recently, a new category of sol-gel glasses has been developed with enhanced bioactivity and open pores enclosed in a mesoporous matrix. In our study, we investigated the effect of 58S sol-gel glasses on the growth and differentiation of mouse calvaria osteoblasts. Two types of granules were used: 58S sol-gel granules and 60S inert glasses used as control. Phase contrast microscopy showed that cells proliferated and formed mineralized bone nodules in both cultures. However, this phenomenon occurred earlier and to a higher degree in cultures with 58S sol-gel glasses. Northern blot analysis of the expression of osteoblastic markers revealed that osteoblasts retained their phenotype in both types of cultures. Interestingly, stimulation of alkaline phosphatase, bone sialoprotein, and osteocalcin was noticed at day 18 in sol-gel cultures when compared with that in control. These data confirm that 58S bioactive glasses are capable of supporting the growth and maturation of primary mouse osteoblasts. In addition, it was shown that 58S glasses affected the gene-expression profile, causing an up-regulation of the major bone markers. These results indicated that 58S sol-gel glasses appeared as suitable candidates for osteoblast scaffolds in the field of bone tissue engineering.

Animals↗