The double-helical structure of double-stranded DNA enables it to form complexes with antibiotics and cytokines. The present study investigated the complex formation for antibiotic or cytokine towards DNA using quarts-crystal microbalance (QCM) technique. The resonance frequency decreases in QCM system linearly upon the increase of adsorbed mass on the QCM sensor at the nanogram level. Biotinylated DNA can easily bind avidin molecules, and DNA could be immobilized onto QCM sensor, which was sputtered with gold. The crystal resonant frequency shift was immediately measured after the injection of daunorubicin hydrochloride, which was an antibiotics, and of basic fibroblast growth factor (b-FGF), which was a growth factor. The present study can monitor the complex formation between daunorubicin hydrochloride or b-FGF and DNA using QCM method, and binding amount of daunorubicin hydrochloride or b-FGF towards DNA can be easily estimated by the frequency decrease. In addition, the difference of binding mode of daunorubicin hydrochloride and b-FGF towards DNA was revealed by the frequency shift. The QCM method is a useful for monitoring DNA complex formation with antibiotics or cytokines.
Collagen sponges are widely used in tissue engineering. Their pore size and pore-interconnection are difficult to control. The purpose of this study was to prepare highly pore-interconnected porous collagen sponges by new pore-forming method. The type I collagen liquid (0.5wt% in HCl solution, pH 3.1) was mixed with chloroform, bubbled by blade-cutter homogenization, gelled by ambient ammonia, freeze-dried and cross-linked by dehydration in vacuum oven at 140°C for six hours. The resultant collagen sponges had the surface brick layer, but sub-surface bulk area about 2mm thick consisting of many well-interconnected homogeneous pores more than 100 mm in size. It was speculated that two porogens such as chloroform and ammonia provided the collagen sponges with well inter-connected pores during freeze-drying. Osteoblast UMR106 cells successfully adhered and multiplied on cut surfaces of prepared collagen sponges. The newly prepared highly pore-interconnected porous collagen sponges might appear to be useful for future oral tissue engineering therapy.
The aim of this study was to examine the effect of alumina blasted titanium disks, prepared by blasting with 7 different graded sizes of alumina particles, on osteoblast-like MG-63 cells. Following an evaluation of the surface conformation and the average surface roughness, the cell morphology, initial cell adhesion, cell proliferation, alkaline phosphatase (ALP) activity and osteocalcin (OC) production were examined. Both the cellular differentiation (ALP activity, OC) and initial cell adhesion increased with a coarser surface. However, differences in surface roughness had no significant effect on cell proliferation.
Few studies have investigated the bone healing of the extracted socket in osteoporosis. The aim of this study is to evaluate the bone response of mandibular incisor extraction in ovariectomized rats using titanium alloy screw. Ovariectomy (OVX) or sham operation was performed at 9 weeks of age. We measured animal body weights each three week to observe the development situation. The titanium alloy screws were placed into the cavities of the mandibular incisor extraction. At 3, 6 and 9 weeks post-insertion, histological observation were performed. Findings in the healing process of the extraction socket after insertion of a titanium screw differed between the Control and OVX groups. The study results indicate that osteoporosis has affect on socket healing after the extraction of ovariectomized rat mandibular incisors. Therefore we may need to consider osteoporosis in patients of bone response after tooth extraction.
The purpose of this study was to evaluate the effect of bone formation induced by recombinant human BMP-2 (rhBMP-2) combined with bioabsorbable material Kurabio®AG (AG) at palatal subperiosteal sites in Wistar rats. AG was freeze-dried alginated gel dressing. Experimental sites were divided into three groups according to the implans : BMP group (rhBMP-2 combined with AG), AG group (AG alone) and Control group. In every group, infected region or atypical cell proliferation was not observed, and new bone formation was observed at 6 weeks after implantation. Thickness of new bone (TNB) of BMP group was significantly higher than that of AG and Control groups. There was no significant difference in TNB between AG and Control groups. These results suggest that rhBMP-2 combined with AG have the ability to promote bone formation, although AG alone do not have any effect on bone formation.