The effects of zinc deficiency on plasma calcium and ionized calcium concentrations were examined in rats. We monitored plasma concentrations of calcium, ionized calcium (Ca2+), parathyroid hormone (PTH) and ionized magnesium (Mg2+) in male 4 week-old Sprague-Dawley rats, that were divided into three groups: zinc-deficient (Zn-Def), low-zinc (Low-Zn), and control pair-fed to Zn-Def (Pair-fed) groups, for 28 days. Comparing to Pair-fed rats, plasma calcium and Ca2+ concentrations of Zn-Def rats were found to be significantly lower after 4, 14, 21, 28 days of feeding. There was no significant change of the plasma Mg2+ concentration among three groups. Comparing to Pair-fed rats, the plasma PTH concentration in Zn-Def rats tended to be higher after 21 days of feeding, and significantly higher after 28 days of feeding. The results suggest that zinc deficiency causes to decrease plasma calcium and Ca2+ concentrations prior to an increase of the plasma PTH concentration.
Various designs are used for surface textures of implants to achieve bone osseointegration on the implant for clinical success. In this in vitro study, Ti sheets with groove and pillar shapes of 500 nm, 1 μm, and 2 μm were made by a nanoimprinting method. Osteoblast-like cells (Saos-2 cells) were seeded on the Ti sheets at a density of 5000 cells/cm2 and cultured in DMEM containing 10% FBS. Cell viability was evaluated by calculating the number of cells that had proliferated and by observing vinculin formation to determine the presence of focal contacts 24 hours after seeding. On the groove and pillar structures, cells were growing at 1 hour and the number of cells at 24 hours was approximately twice that on smooth surfaces as a control. The number of cells on the 500-nm grooves and pillars was higher than that on the other patterns. After incubation for 24 hours, vinculin formation had extended to the ridges of the groove and pillar structures as an evidence of cell adhesion. The increase in vinculin was correlated with cell differentiation. The results indicate the importance of the biological effect of surface modification on Ti sheets and the potential use of surface modification to improve osseointegration.
Tumor vasculature has a key role in supplying the oxygen and nutrients. Angiogenesis is necessary for tumor growth, survival, and metastasis, therefore, the suppression of tumor angiogenesis is one of the strategies to suppress the tumor growth. TZT-1027, an anti-microtubule agent, has not only cytotoxicity against cancer cells but also inhibitory effects against tumor vasculature. We estimated the effect of combination of TZT-1027 and X-ray on tumor angiogenesis. Human endothelial cells (HUVEC and ECV304 cell line) were irradiated by 4MV X-ray. The invasive, migration and tube forming capabilities of human endothelial cells were significantly suppressed by TZT-1027 with pre-irradiation. However, the cells administrated regent after irradiation did not inhibit the capabilities significantly. In this study, we found that combination with TZT-1027 and irradiation exhibited synergistic effects of anti-angiogenesis. These results suggest the possibility that TZT-1027 in the combination with irradiation is one of strategy against cancer treatments.
We produced highly pressed nano-hydroxyapatite/collagen composites (P-nHAP/COL) by Newton press. The aim of this study was to investigate osteogenic differentiation profiles in osteoblastic SaOS-2 cells cultured on P-nHAP/COL and pressed collagen (P-COL) as control for 1, 2, 3 and 4 weeks. Total RNA were extracted from cultured cells, and expressions of osteogenic-differentiation related genes were evaluated with quantitative real-time (RT) PCR using primer sets of alkaline phosphatase (ALP), type 1 collagen (COL1), bone Sialo protein (BSP) and osteocalcin precursor (BGLAP) genes as well as β-actin gene. The cultured cells were also observed with scanning electron microscopy (SEM). RT-PCR analyses revealed that osteogenic differentiation was more accelerated on P-nHAP/COL than on P-COL, especially revealed by up-regulation with time of BGLAP gene. In SEM images, SaOS-2 cells on P-COL were either cubic or fibroblastic up to 4 weeks, but those on P-nHAP/COL appeared as granular or highly stretched. The obtained results suggested that P-nHAP/COL could be employed as a new osteo-conductive bone substitute material.
The present study investigated the role of matrix on the behavior of elements in HAp-added conventional glass ionomer cement (GIC), referred to as "apatite-ionomer cement (AIC)." The AIC samples were produced by replacing 8-16 wt% of GIC powder with porous spherical-shaped HAp. One-half of the samples had the matrix-rich layer removed. The AIC and GIC samples with and without a matrix-rich layer underwent multi-element analysis using a fluoride electrode and ICP-AES. The antibacterial activity of the samples against S. mutans was also evaluated using ATP-luminescence methods. The mineral ion release properties and antibacterial activity of AICs were superior to those of GIC. The concentrations of elements released from GIC and AIC samples with a matrix-rich layer were significantly greater than those from GIC and AIC samples without the matrix-rich layer. The luminescence intensities of S. mutans suspensions containing immersed AICs were significantly lower than those of suspensions containing GIC.
In the present study, we developed patterned apatites with grooves, pillars, and holes by micro-molding. The effects of the patterns on adhesion of the human osteoblastic cell line Saos-2 were investigated. The patterned apatites were fabricated with apatite cement paste using the micro-molding method. The number of attached cells and ratio of cell spreading were estimated by a cell adhesion assay using Saos-2. The resulting patterns of grooves, holes, and pillars at the micro-/submicro-level were easily transferred using the corresponding mold. Saos-2 cells were well orientated on the grooves and filopodia were radially elongated on pillars. The number of attached cells on the patterned apatite was higher than that on the planar apatite. Interestingly, the tendency of increasing of ratios of spreading cells was similar to that of decreasing of water contact angle on apatite pillars. These results show that the adhesion of Saos-2 cells was affected by the type and size of the apatite patterns.
The development of nanomaterials has promoted a marked improvement of performance and studies on the addition of new functions. Nanomaterials may be combined in many dental component materials in the future. However, at present, the results of studies on the biological safety of nanomaterials are insufficient. Cells have an active nanomaterial uptake mechanism, i.e., phagocytosis, and this is completely different from the mechanism of incorporating dissolved chemical substances. Moreover, products prepared with nanomaterials alone are rarely developed, and nanomaterials are likely to be added to conventional chemical substances. In this case, there are no data on changes in the toxicity caused by interaction between nanomaterials and dissolved chemical substances. Thus, we investigated the cytotoxicity of nano-zinc oxide alone and changes in the cytotoxicity of Bis-GMA, which is used as a matrix resin monomer of composite resin, at its non-cytotoxic concentration. Bis-GMA cytotoxicity increased in the nano-zinc oxide group compared with that in the control group in both 2- and 3-dimensional culture using collagen gel. It was clarified that the cytotoxicity of Bis-GMA slightly increased due to interaction in the nano-zinc oxide and Bis-GMA mixture.