Contrast-enhanced (CE)-MR image is useful to distinguish cystic and solid portions on multilocular lesion, however, the CE-MR examination is contraindicated in patients with kidney disease. Fluid-attenuated inversion recovery (FLAIR) image is one of methods which signal of fluid is suppressed. This study investigated qualitatively and quantitatively whether FLAIR images were useful for detecting and differentiating cystic and solid portions of multilocular ameloblastomas. We retrospectively reviewed 11 cases of multilocular ameloblastoma. FLAIR and short T1 inversion recovery (STIR) sequences were performed in all cases, CE-MR images in 10 cases, and T1-weighted images (T1WI) in 7 cases. FLAIR, STIR, CE-MR, and T1WI images were visually evaluated (qualitative analysis). Signal-to-noise ratio (SNR) of cystic and solid portions were measured and compared among the images of all sequences (quantitative analysis). FLAIR imaging could detect cystic portions with very low SI in all cases because cystic fluid was well suppressed on the images, and the solid portion showed intermediate SI. On some STIR images, the solid portion was masked by the markedly high SI of the cystic fluid. CE-T1WI and CE-FLAIR images showed no enhancement of the cystic portion but enhancement of the solid portion. On FLAIR image, SNR of solid was higher than cystic portion (p < 0.05). Cystic and solid portions of a lesion could be detected and distinguished on FLAIR imaging. FLAIR images are thus useful for diagnosing multilocular ameloblastoma when CE-MR cannot be performed.
Osteoporosis, caused by loss in bone mass, has become a major concern in Japan. Several studies have indicated a relationship between bone mass and gene polymorphisms; however, the effect of lifestyle habits is yet to be explored. The aim of the present study was to identify vitamin D receptor (VDR) gene polymorphism and lifestyle factors associated with bone mass in Japanese female college students. The subjects comprised 317 female college students aged between 20 and 24, all of whom were living in the Kanto region at the time of the study. Bone mass measurement was based on qualitative ultrasound (QUS). The subjects were asked what type of sport they used to play in their junior high school and high school days. Gene polymorphism for the restriction enzyme TaqI digestion site (rs731236) were detected by real-time PCR using TaqMan probes. No significant difference in the bone mass was observed between the VDR polymorphisms (TT versus TC + CC). The present study did not demonstrate any correlation between VDR polymorphism and bone mass. Similarly, no correlation was observed between nutritional intake and bone mass. Meanwhile, the results of multiple linear regression analysis ascertain that high BMI levels and the experience of high-impact exercise during junior high school or high school have an independent positive effect on bone mass. These results suggest that BMI and exercise are highly likely to be important factors in increasing bone mass.
Free vascularized fibular flaps (FVFF) have an advantage in their applicability for extensive bone defects in the maxillofacial region after surgery, and have therefore been employed in maxillofacial reconstruction in Western countries. For successful application of FVFF, anatomical understanding of the fibula is necessary. Many studies on the fibula of patients and autopsied bodies have been reported. An increase in demand is predicted in Japan, but few studies on the morphological characteristics of the fibula of Japanese have been reported. Many unclear points remain and no study has focused on sex differences. In this study, the 3-dimensional morphology of the fibula of Japanese was observed, the previously unreported distribution and location of the feeding blood vessels were examined, and the region containing sufficient bone mass for maxillofacial reconstruction was anatomically evaluated. Images of the excised fibula were acquired using CT for medical use and subjected to 3-dimensional reconstruction. Prior to measurement, the fibula was divided into 6 parts between the apex of the fibular head and apex of the lateral malleolus. The 4 central regions were set as regions of interest and the diameters of the fibular cross sections were 3-dimensionallymeasured. In addition, the distribution of the feeding blood vessels to the fibula was macroscopically observed and classified. On 3-dimensional bone morphology measurement, the width (diameter) of fibula cross section between the anterior margin and posterior aspect was the largest, followed by that between the medial crest and lateral aspect. In the regions of interest, the mean width between the anterior margin and posterior aspect, which corresponded to the grafted bone height, exceeded 10 mm, and the mean width between the medial crest and lateral aspect and between the posterior margin and medial aspect, which became the buccolingual width of the grafted bone, exceeded 6 mm, confirming that the graft thickness is sufficient for grafting. Furthermore, the blood vessels feeding the fibula entered the bone in the central one-third region in all preparations. Inclusion of the central one-third region was suggested to be effective for vascularized fibular grafting.
Objective: This study aims to synthesize a new biodegradable and biomineralized guided bone regeneration membrane. Experimental Methods: Poly(propylene carbonate) (PPC) and nanohydroxyapatite (nHAp) were prepared by solvent casting/particulate leaching and made into membranes with different compositions (0%,10%,20%, 30%, and 40% nHAp/PPC). Their mechanical properties, cell compatibilities and fibroblast barrier functions were studied in vitro. Results: Scanning electron microscopy showed that the nHAp/PPC membrane displayed a smooth and rough surface similar to that of periosteal structure. Tensile test results indicated that the tensile strengths of 10% and 20% nHAp/PPC groups were significantly higher than that of 0% nHAp/PPC group. With the increased nHAp content, the tensile strength of nHAp/PPC membrane and the hydrophilic angle were decreased, and the mineralization ability in vitro was enhanced. After 4 weeks of degradation in vitro, only 40% of the nHAp/PPC group exhibited significantly higher rate of weight loss than that of the 0% nHAp/PPC group. Additionally, scanning electron microscopy showed that MG63 cells adhered to the rough surface of the nHAp/PPC membrane. Five groups of nHAp/PPC membranes showed good fibroblast barrier in vitro .Taken together, this in vitro evaluation suggests that the nHAp/PPC membrane is suitable as a guided bone regeneration membrane.
Intermittent administration of parathyroid hormone (PTH) is known to increase bone mass for the treatment of osteoporosis. The aim of this study was to evaluate the benefits of local intermittent administration of PTH for bone regeneration in rats with cranial bone defects. Cranial bone defects were induced under anesthesia using a trephine bur (diameter, 4.3 mm) in 8-week-old male Wistar rats, which were then divided into four groups for further treatment. In the PTH-3 and PTH-1 groups, animals received PTH at 14.1 μg/kg in an absorbable collagen sponge placed near the bone defect. Animals in the collagen group received saline at 0.05 ml using the same method, while control animals received only sham surgery. Following surgery, PTH-3 animals received two subcutaneous injections of PTH (14.1 μg/kg) at the experimental site, while the PTH-1, collagen, and control animals each received saline (0.05 ml). All animals were sacrificed at 21 days after surgery. The ratio of new bone mineral content to total defect volume (BMC/TV) at the experimental sites was evaluated using micro-computed tomography. Tissue sections were analyzed by hematoxylin and eosin staining and immunohistochemistry with anti-alkaline phosphatase (ALP), anti-dentin matrix protein 1 (DMP1) and anti-Osterix antibodies. The BMC/TV ratio was significantly higher in the PTH-3 and PTH-1 groups than in the collagen group. The ratio of new bone to defect area (N/D%) was significantly higher in PTH-3 animals than in controls. ALP-positivity was more widely distributed in new bone in PTH-3 animals than in the other groups, and regions of DMP1-positivity and Osterix-positivity were also more widespread in these animals. These findings suggest that local intermittent administration of PTH enhances bone regeneration in rats with cranial bone defects.
The aim of this experimental study was to investigate the effects of ozone therapy on tendon healing in rats. A total of 60 adult male, 1-year old Wistar albino rats weighing 450-500 g were randomly assigned to the ozone group (Group 1, n:30) or the control group (Group 2, n:30). In both groups, the right and left Achilles tendons were cut transversally and then sutured. Group 1 underwent ozone treatment rectally (40 μg/mL) four times a week, while Group 2 received only nutrition and routine care. Ten rats from each group were sacrificed and evaluated in respect of histopathological and biomechanical properties at the end of the 2nd, 4th and 6th weeks. There were statistically significant differences between the groups in respect of fibroblastic proliferation (p=0.042) and inflammation (p=0.001) in the 2nd week. Fibroblastic proliferation was higher in the ozone group, and inflammation in the control group was found to be higher. Remodeling and fibroblastic proliferation were significantly increased in the ozone group in the 4th week (p = 0.007 and p=0.003, respestively). In the 6th week, high remodeling and high fibroblast proliferation were observed in the ozone group compared with the control group (p=0.020, p=0.004, respectively). The biomechanical results revealed that the ozone group had significantly higher breaking load and breaking tensile stress values than the control group in the 6th week (p = 0.007, p = 0.003, respectively). The histopathological and biomechanical findings indicated that the ozone therapy had beneficial effects on Achilles tendon rupture healing.
It is necessary to acquire osseointegration at an early stage in implant therapy, and a number of various approaches using titanium and cells have been evaluated. Mesenchymal cells exist in dental pulp and have been confirmed to form osseous hard tissues in vitro. However, there have been few studies on the application of dental pulp-derived stem cells in implant therapy. In this study, we cultured osteoblast-like cells derived from rat incisor pulp on titanium discs and evaluated their proliferation and differentiation potential. We further examined the possibility of applying dental pulp-derived cultured cells during titanium implant placement. Dental pulp cells were collected from the incisors of SD rats and then cultured on titanium discs. The titanium discs were treated with sulfuric acid after sandblasting with alumina. Cell proliferation and differentiation potential was evaluated by WST-1 assay, alkaline phosphatase (ALP) activity, and Alizarin red staining. Finally, the dental pulp-derived cultured cells were used in an implant test to measure the mechanical strength of the bone-titanium integration. ALP activity was significantly increased in cultured cells after 10 days compared with that after 5 days. The area of Alizarin red-positive staining increased significantly in a time-dependent manner upon incubation for 10, 20, and 30 days. The mechanical strength achieved at 2 weeks after implantation in the experimental group was significantly greater than that in the control group. These results demonstrate that osteoblast-like cells derived from rat dental pulp and cultured on surface-treated titanium discs maintained their cell differentiation potential. The results of the implant test cultured the potential application of dental pulp-derived cells to rapidly achieve osseointegration of titanium implants.
The aim of this study was to investigate whether an increase in the inorganic phosphate (Pi) concentration through the sodium-dependent phosphate cotransporters, Pit-1 and Pit-2 is involved in the differentiation of fibroblasts into osteoblasts in human PDLfs (hPDLfs). Expression of Pit-1 and Pit-2 mRNA from three different donors was examined by RT-PCR. Pit-1 and Pit-2 proteins were examined by western blotting. Localization of Pit-1 and Pit-2 was examined with immunocytochemistry. Phosphonoformic acid (PFA) was used to inhibit Pi transport. Time-course assays of Pi concentration in the hPDLfs were performed in the three different media; standard medium, calcification medium, and calcification medium with 1.0 mM PFA. Pit-1 and Pit-2 were expressed in hPDLfs at the mRNA and protein levels. The intracellular Pi (intra-Pi) concentration in hPDLfs incubated only in calcification medium was significantly higher than those in the other media, and calcification was observed in this medium. The intra-Pi concentration decreased by PFA, and calcification was not observed. The hPDLfs showed expression of Runx2 and osterix: specific marker of osteoblast in the calcification medium. The results indicated that the increase in the Pi concentration through Pit-1 and Pit-2 is play a critical role in the differentiation of PDLfs to osteoblasts.
We aimed to study the biomechanical characteristics of sciatic nerve after transplantation with poly lactic-co-glycolic acid (PLGA) catheter combined with bone marrow mesenchymal stem cells (BMMSCs) and extracellular matrix (ECM) gel in rabbit model of sciatic nerve injury, so as to provide biomechanics and other basis for the clinical practice. The rabbit sciatic nerve injury model was used in this study. The rabbits with sciatic nerve injury received autologous nerve transplantation (ANT), PLGA catheter combined with BMMSCs transplantation and PLGA catheter combined with BMMSCs and ECM gel transplantation respectively and then correspondingly grouped into ANT group, PCBT group and PCBET group. Twenty-four weeks later, the sciatic nerves in each group were used for electrophysiological examination, histomorphological observation and tensile mechanical properties test. Amplitude (AMP) and motor nerve conduction velocity (MNCV) values of the sciatic nerves in PCBET group were remarkably higher than those in the PCBT group and ANT group with statistical significance (P<0.05). The tensile elastic limit stress, elastic limit strain, maximum stress and strain in PCBET group were all larger than those in the PCBT group and ANT group with a significant difference (P<0.05). PLGA catheter combined with BMMSCs or PLGA catheter combined with BMSCs and ECM gel can restore the elasticity and toughness of the injured sciatic nerve at some extent, and has obvious recovery effect on the function of the injured sciatic nerves.
The alterations of osteon morphology were caused by many factors, such as age, osteoporosis, and physical activity level. It is known that fluid flow in osteon play an important role in osteocyte mechanotransduction and hard tissue health, but less is known about these alterations of osteon morphology affect the response of fluid flow. This study aims at using poroelastic finite element analysis to investigate whether these variations of osteon morphology caused by ageing, osteoporosis, or physical activity level can affect the responses of osteon poroelastic behaviors. In this paper, the COMSOL Multiphysics software was used to establish osteon model with different morphological parameters (shape, cross-section curvature, cross-section area and wall thickness), and the effects of these parameters on the fluid pressure (P) and velocity (V) were investigated. The results showed that the osteon shape had large effects on P and V, and the peak value of P and V increased with the increase of the osteon oblateness. Then, we noticed that, the P and V had obviously positive correlation with cross-section curvature in the same region or lamellar structure in an osteon. The larger cross-sectional area caused a smaller P and V. However, the effects of osteon wall thickness showed the opposite way, the P and V amplitudes increased with the increase of the wall thickness. Significantly, our findings indicated that the wall thickness have a larger effect on P and V than that of the cross-section area. The findings of this work indicate that the alterations of osteon morphology associated with age, osteoporosis or physical activity level had significant influence on P and V in the osteon, and affect the signal transduction in the bone which have the potential research and applications value in treatment osteoporosis and other skeletal diseases.
Spheroid culture systems more accurately recreate the in vivo microenvironment and are susceptible to factors that induce differentiation. In this study, we assessed whether bone morphogenetic protein (BMP)-2 induces enhanced osteogenic differentiation in spheroid-derived mesenchymal stem cells (MSCs). MSC spheroids were generated from human adipose tissue-derived MSCs using low-binding plates. Osteogenic differentiation of monolayer and spheroid-derived MSCs was induced by osteogenesis induction medium (OIM) with or without BMP-2. Increased alkaline phosphatase and Alizarin Red staining were observed in spheroid-derived MSCs treated with a mixture of OIM and BMP-2, compared with monolayer MSCs. Spheroid-derived MSCs had increased mRNA and protein expressions of osteogenic runt-related transcription factor 2 (Runx2) and osterix (OSX). The intranuclear expression of OSX was also observed in spheroid-derived MSCs treated with the mixture of OIM and BMP-2. In addition, spheroid-derived MSCs with BMP-2 treatment showed the upregulation of Smad5 mRNA and phosphorylated Smad1/5, suggesting that the Smad-BMP signaling pathway is enhanced in these cells. Our data indicate that the Smad-dependent BMP signaling pathway accelerates osteogenic differentiation in spheroid-derived MSCs, compared with monolayer MSCs.
Alkali-treated titanium with nanonetwork structure (TNS) is strongly osteogenic but not antibacterial in nature. In contrast, titanium doped with silver nanoparticles (Ag-NPs) possesses excellent and long-term antibacterial activity, but induces significant levels of intracellular reactive oxygen species that may cause cytotoxicity. We attempted to enhance the antibacterial activity of TNS by doping with Ag-NPs and prevent intracellular reactive oxygen species formation by coating with the antioxidant N-acetyl cysteine. Importantly, TNS doped with Ag-NPs and coated with N-acetyl cysteine has similar antibacterial activity against Staphylococcus aureus as TNS doped with only Ag-NPs, and inhibited bacterial attachment, proliferation, and biofilm formation by Actinomyces oris. However, TNS doped with Ag was significantly cytotoxic for rat bone marrow mesenchymal stem cells, whereas TNS doped with Ag and coated with N-acetyl cysteine supported cell viability and differentiation to a certain extent by suppressing overproduction of intracellular reactive oxygen species. Collectively, our results suggest that application of N-acetyl cysteine enhances the biocompatibility of TNS doped with Ag-NPs without compromising antibacterial activity, yielding a material with clinical potential.
Real-time three-dimensional navigation images can facilitate minimally invasive and accurate surgery. The aim of this study was to clarify the usefulness of a real-time three-dimensional navigation system for removal of dental implants. The authors designed a retrospective study and analyzed patients who underwent implant removal surgery with a real-time three-dimensional navigation guide under general anesthesia. Six patients (age, 64.3 ± 8.8 years) were included in this study. The procedures involved the maxilla and the mandible in four and two patients, respectively. The implant bodies were adjacent to the maxillary sinus or nasal cavity in all the maxillary cases, and to the mandibular canal in both mandibular cases. Adjacent implant bodies and adjacent teeth that had to be preserved were noted in 1 and 5 cases, respectively. All cases required elevation of a mucoperiosteal flap for removal of the implant bodies, and five cases required removal of the alveolar bone. No postoperative complications were observed, and the adjacent teeth and implants could be preserved in all cases. This study suggests that a real-time three-dimensional navigation system under general anesthesia is useful for dental implant removal surgery in cases with no absorption of alveolar bone around the implant bodies, cases wherein the implant bodies have migrated into an inappropriate position, and cases with adjacent teeth or implant bodies that have to be preserved intact.