Fluorinated Bioactive Glass Nanoparticles: Enamel Demineralization Prevention and Antibacterial Effect of Orthodontic Bonding Resin.

Orthodontic treatment involving the bonding of fixed appliances to tooth surfaces can cause white spot lesions (WSLs). WSLs increase the likelihood of cavity formation and hence require preservation and prosthetic restoration. Therefore, the prevention of WSLs is of greater importance than treatment. Application of fluoride or the use of fluoride-containing mouthwash can prevent WSLs, but this requires patient cooperation and additional time and cost. Bioactive glass containing 2.5% fluoride was synthesized and mixed with the orthodontic bonding adhesive Transbond XT Low Flow (LV) at ratios of 1, 3, and 5% to prepare orthodontic adhesive samples. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the samples. The Vickers hardness test, bracket retention test, and adhesive remnant index (ARI) of the samples were analysed to determine their mechanical properties. To determine the biological cytotoxicity, the cell activity of the samples was evaluated using cell viability tests and the antibacterial activity was analysed using Streptococcus mutans. To evaluate the anti-demineralization effect, the sample was bonded to extracted teeth and a pH cycle test was performed. Micro computed tomography data were obtained from the bonded teeth and sample, and the anti-demineralization effect was evaluated using the ImageJ software program. The Vickers hardness of the sample was higher than that of LV and was dependent on the concentration of fluoride-containing bioactive glass (FBAG). The bracket retention test and ARI of the sample showed no significant differences from those of LV. The cell viability test showed no significant changes at 24 and 48 h after application of the sample. The fluoride ion release test indicated an ion release rate of 9.5-17.4 µg/cm2. The antibacterial activity of the experimental group containing FBAG was significantly higher than that of the LV group. The anti-demineralization test showed a concentration-dependent increase. However, the resin containing 5 mass% FBAG (FBAG5) showed a statistically-significant increase compared with LV. The orthodontic adhesive containing FBAG showed antibacterial and anti-demineralization effects, thus indicating possible WSL prevention activity.

Enamel Surface Remineralization Effect by Fluorinated Graphite and Bioactive Glass-Containing Orthodontic Bonding Resin.

All orthodontic appliances are potentially cariogenic. The plaque around the orthodontic appliance can make demineralization on tooth surface causing white spot lesion (WSL). The most effective method to prevent WSL is Fluoride appliance and gargling, but this requires patient cooperation, which consumes additional treatment time and cost. As suggested in this study, biomaterials like bioactive glass and fluorinated graphite (FGt) having antibacterial and anti-demineralization ability effective and easy to use in the clinic. To clinically use orthodontic bonding resins containing Graphite Fluoride BAG (FGtBAG), its properties, biological stability, antimicrobial activity, and remineralization effect must be verified. BAG was mixed with 2.5% FGt containing 51 to 61% fluorine. This mixture was mixed with the CharmFill Flow (CF) in the ratios of 1, 3, and 5 wt%. Microhardness and shear bond strength tests were performed to evaluate its mechanical properties. MTT (3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetra) assay was performed for evaluating its safety. Streptococcus mutans, which is major cariogen by producing lactic acid, was evaluated for antibacterial ability of reducing WSL. In addition, x-ray images were obtained by CBCT (Cone beam computed tomography) after a pH cycle. The remineralization effect was verified in vivo and by Image J. FGtBAG did not differ significantly from CF in mechanical tests. The MTT assay found no significant differences between the groups. The antibacterial activity of FGtBAG at 24 h and 48 h was significantly higher than that of CF. The fluoride release rate tended to increase with the FGtBAG content. The pH cycle results showed that FGtBAG had higher concentration-dependent remineralization effect than CF. The results of this study suggests that orthodontic resins containing FGtBAG can prevent WSL owing to their antibacterial activity and remineralization effect.

Production and Purification of Recombinant Glucocerebrosidase in Transgenic Rice Cell Suspension Cultures.

Gaucher disease, which is caused by deficiency of glucocerebrosidase (GCD), is currently treated by enzyme replacement therapy. Plant-based systems produce glycoproteins and can be combined with targeting strategies to generate proteins with terminal mannose structures for macrophage uptake. However, the gliding step for the purification is essential since the produced protein still exists inside cells. In the case of rice-amylase 1A (RAmy1A) secretion signal peptide, GCD protein is secreted outside of cells and simplifies the purification step. Here, an established cell line was confirmed as having fundamental characteristics of growth and production. GCD from transgenic calli was examined by Western blot analysis and compared with that from Chinese hamster ovary (CHO) cells. Calli expressing high levels of GCD were used to establish suspension cell lines. Growth and production characteristics were investigated in suspension cell cultures. Production of GCD in suspension cultures was confirmed upon induction for 12-24 h. The amount of GCD in medium increased until 60-84 h and decreased thereafter. Purification of GCD was performed in three steps (ion exchange, hydrophobic interaction, and size exclusion chromatography) and verified. Purified GCD was able to hydrolyze the synthetic substrate. Thus, a rice expression system could be a suitable alternative to GCD expression in mammalian cells.

Differences Among Deviations, Genders, and Observers in the Perception of Eye and Nose Asymmetry.

PURPOSE: This study investigated the degree and range of recognition of canting of the interpupillary line and deviation of the nose, which were regarded as "normal," "acceptable," and "needing surgical correction," according to different observer groups. MATERIALS AND METHODS: Four different groups (40 each for laypeople, dental students, general dentists, and orthodontists) rated 11 simulated asymmetric images with canted eyes and a deviated nose separately. The raters categorized each image as normal, socially "acceptable" and not requiring correction, or abnormal and would benefit from correction. Survival analysis was used to evaluate the scope of perception. RESULTS: The degree of recognition for eye-canting and nose deviation was 2.31 and 2.92, respectively. Eye-canting and nose deviation had lower degrees of recognition in the clockwise direction (2.13°) and on the left side (2.65°), respectively. Women showed a lower degree of the "upper limit of the acceptable range" for canted eyes, and men showed a lower "degree of recognition" and "upper limit of the acceptable range" for a deviated nose. Orthodontists showed a larger upper limit of the acceptable range for eye-canting (P < .001). CONCLUSIONS: The perceptions of asymmetry of canted eyes and deviated nose were affected by gender, direction of asymmetry, and observer groups.

Elucidating rice cell metabolism under flooding and drought stresses using flux-based modeling and analysis.

Rice (Oryza sativa) is one of the major food crops in world agriculture, especially in Asia. However, the possibility of subsequent occurrence of flood and drought is a major constraint to its production. Thus, the unique behavior of rice toward flooding and drought stresses has required special attention to understand its metabolic adaptations. However, despite several decades of research investigations, the cellular metabolism of rice remains largely unclear. In this study, in order to elucidate the physiological characteristics in response to such abiotic stresses, we reconstructed what is to our knowledge the first metabolic/regulatory network model of rice, representing two tissue types: germinating seeds and photorespiring leaves. The phenotypic behavior and metabolic states simulated by the model are highly consistent with our suspension culture experiments as well as previous reports. The in silico simulation results of seed-derived rice cells indicated (1) the characteristic metabolic utilization of glycolysis and ethanolic fermentation based on oxygen availability and (2) the efficient sucrose breakdown through sucrose synthase instead of invertase. Similarly, flux analysis on photorespiring leaf cells elucidated the crucial role of plastid-cytosol and mitochondrion-cytosol malate transporters in recycling the ammonia liberated during photorespiration and in exporting the excess redox cofactors, respectively. The model simulations also unraveled the essential role of mitochondrial respiration during drought stress. In the future, the combination of experimental and in silico analyses can serve as a promising approach to understand the complex metabolism of rice and potentially help in identifying engineering targets for improving its productivity as well as enabling stress tolerance.

Bioreactor engineering using disposable technology for enhanced production of hCTLA4Ig in transgenic rice cell cultures.

Two kinds of disposable bioreactors, air-lift disposable bioreactors (ADB) and wave disposable bioreactors (WDB) were compared with stirred-tank reactors (5-L STR). These bioreactors were successfully applied to transgenic rice cell cultures for the production of recombinant human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig). In both systems, a fed-batch culture method was used to produce hCTLA4Ig efficiently by feeding concentrated amino acids and production levels were enhanced when dissolved oxygen (DO) level was regulated at 30% using pure oxygen sparging. Agitation and aeration rate during cultivation in ADB and WDB were determined by the same mixing time. The results in both disposable bioreactors showed similar values in maximum cell density (11.9 gDCW/L and 12.6 gDCW/L), doubling time (4.8- and 5.0-day), and maximum hCTLA4Ig concentration (43.7 and 43.3 mg/L). Relatively higher cell viability was sustained in the ADB whereas hCTLA4Ig productivity was 1.2-fold higher than that in WDB. The productivity was improved by increasing aeration rate (0.2 vvm). Overall, our experiments demonstrate pneumatically driven disposable bioreactors are applicable for the production of recombinant proteins in plant cell cultures. These results will be useful for development and scale-up studies of disposable bioreactor systems for transgenic plant cell cultures.

Process characterization of hCTLA4Ig production in transgenic rice cell cultures using a 3-L bioreactor.

Most of the technical know-how and experience of bioreactor engineering is applicable to plant cell cultures. In this study, transgenic rice cell cultures using RAmy3D promoter were used for the production of human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig). In process aspect, the rice cells during production phase are strongly influenced by hydrodynamic stresses, such as shear stress and bubble burst. Therefore, the effects of agitation and aeration rates on cell growth and hCTLA4Ig production were investigated in a 3-L multi-bioreactor. By increasing over 240 rpm, the detrimental effects on cell growth and hCTLA4Ig production were observed. At an aeration rate of 0.3 vvm, relative cell viability sharply decreased 2 days earlier than those of lower aeration rates. In addition, it was confirmed that the specific yields and the specific productivity at 0.3 vvm were superior to those values at 0.05 vvm. Overall, higher aeration rate showed the improved hCTLA4Ig production in combination experiment. High aeration rates in general, however, have an undesired effect as excessive aeration was found to negatively affect the quality of hCTLA4Ig. Consequently, the hydrodynamic conditions must be tightly regulated during bioreactor operation in order to enhance hCTLA4Ig productivity and quality in transgenic rice cell cultures.