Kazuyuki Yusa

In vitro prominent bone regeneration by release zinc ion from Zn-modified implant.

Zinc is one of the trace elements which induce the proliferation and the differentiation of the osteoblast. In the previous study, we found that zinc ions (Zn(2+) ion)-releasing titanium implants had excellent bone fixation using a rabbit femurs model. In this study, we isolated the Zn(2+) ions (eluted Zn(2+) ion; EZ) released from the implant surface, and evaluated the effect of EZ on the osteogenesis of human bone marrow-derived mesenchymal cells (hBMCs). In the result, it was found that the EZ stimulated cell viability, osteoblast marker gene (type I collagen, osteocalcin (OC), alkaline phosphatase (ALP) and bone sialoprotein (BSP)) expressions and calcium deposition in hBMCs.

Zinc-modified titanium surface enhances osteoblast differentiation of dental pulp stem cells in vitro

Zinc is an essential trace element that plays an important role in differentiation of osteoblasts and bone modeling. This in vitro study aimed to evaluate the osteoblast differentiation of human dental pulp stem cells (DPSCs) on zinc-modified titanium (Zn-Ti) that releases zinc ions from its surface. Based on real-time PCR, alkaline phosphatase (ALP) activity and Western blot analysis data, we investigated osteoblast differentiation of DPSCs cultured on Zn-Ti and controls. DPSCs cultured on Zn-Ti exhibited significantly up-regulated gene expression levels of osteoblast-related genes of type I collagen (Col I), bone morphogenetic protein 2 (BMP2), ALP, runt-related transcription factor 2 (Runx2), osteopontin (OPN), and vascular endothelial growth factor A (VEGF A), as compared with controls. We also investigated extracellular matrix (ECM) mineralization by Alizarin Red S (ARS) staining and found that Zn-Ti significantly promoted ECM mineralization when compared with controls. These findings suggest that the combination of Zn-Ti and DPSCs provides a novel approach for bone regeneration therapy.

Anti-Melanogenesis Effect of Glechoma hederacea L. Extract on B16 Murine Melanoma Cells

Glechoma hederacea L. (Labiatae) has been used in folk medicine to treat various ailments for centuries. We investigated the effects of G. hederacea extract on melanogenesis in B16 melanoma cells. It significantly reduced both the cellular melanin content and tyrosinase activity in a concentration-dependent manner. An MTT assay did not reveal any obvious cytotoxicity. Furthermore, we found that G. hederacea extract decreased tyrosinase and microphthalmia-associated transcription factor protein expression, but did not inhibit tyrosinase-related protein-1 and tyrosinase-related protein-2 expression. RT-PCR analysis indicated that the antimelanogenic effect of G. hederacea extract might be due to inhibition of tyrosinase gene transcription. Moreover, this effect is regulated via suppression of microphthalmia-associated transcription factor protein expression. Our data indicate that G. hederacea extract inhibits melanin synthesis in B16 melanoma cells but is not cytotoxic. Hence it might prove a useful therapeutic agent for treating hyperpigmentation and an effective component of whitening cosmetics.

Eluted zinc ions stimulate osteoblast differentiation and mineralization in human dental pulp stem cells for bone tissue engineering

OBJECTIVE Zinc is an essential element for proliferation, differentiation and survival in various cell types. In a previous study, we found that zinc ions released from zinc-modified titanium surfaces (eluted zinc ions; EZ) stimulate cell viability, osteoblast marker gene expression and calcium deposition in human bone marrow-derived mesenchymal cells (hBMCs). The aim of the present study was to investigate the effects of EZ on osteoblast differentiation among dental pulp stem cells (DPSCs) in vitro. METHOD In this study, we evaluated the effects of EZ on osteogenesis in DPSCs. Osteoblast and osteoclast marker gene expression was evaluated by real-time PCR. We also evaluated alkaline phosphatase (ALP) staining and calcium deposition. RESULTS We found that EZ stimulated osteoblast marker gene (type I collagen, alkaline phosphatase (ALP), osteocalcin (OCN) and Runx2) expression, vascular endothelial growth factor A (VEGF-A), and TGF-beta signaling pathway-related gene expression after 7days of incubation. Osteoclastogenesis occurs in a receptor for activated nuclear-factor kappa B ligand (RANKL)/osteoprotegerin (OPG)-independent manner. Real-time PCR analysis revealed that EZ did not affect RANKL or OPG mRNA expression. It was also revealed that EZ induced alkaline phosphatase (ALP) staining and calcium deposition in DPSCs. Collectively, these results demonstrate the potential for clinical application to prospective treatment of bone diseases.

Functional and aesthetic rehabilitation with maxillary prosthesis supported by two zygomatic implants for maxillary defect resulting from cancer ablative surgery: a case report/technique article

We report herein a case of functional and aesthetic rehabilitation with maxillary prosthesis supported by only two zygomatic implants for a patient with severe maxillary defect resulting from subtotal maxillectomy for malignant melanoma of the upper gingiva. A 76-year-old woman was referred to our facility with non-painful discoloration of the upper gingiva. After several examinations, a clinical diagnosis of malignant melanoma of the upper gingiva (cT3N1M0 stage IVA, American Joint Committee on Cancer) was made. Subtotal maxillectomy utilizing Le Fort I osteotomy and functional neck dissection were performed. A conventional resection denture was made and employed postoperatively, but was unable to be suitably retained due to insufficient residual maxillary structures. Six months after tumor resection, two zygomatic implants were inserted into bilateral zygomatic bones. Magnetic attachments were applied as a mechanism for attaching the implants and resection denture. After application of these implants, retention and stability of the prosthesis was considerably improved. The patient became able to eat a normal diet. From an aesthetic perspective, the depressed upper lip was also properly restored, leading to an acceptable facial appearance.

Facilitation of bone resorption activities in synovial lavage fluid patients with mandibular condyle fractures

The aim of this study was to investigate the bone resorption effect of the mediators delivered in joint cavity of patients with mandibular condyle fractures by detecting osteoclast markers using cellular biochemistry methods, and by analysing bone resorption activities via inducing osteoclast differentiation of the infiltrated cells from arthrocentesis. Sixteen joints in 10 patients with mandibular condyle fractures were evaluated. The control group consisted of synovial fluid (SF) samples from seven joints of four volunteers who had no clinical signs or symptoms involving the temporomandibular joint (TMJ) or disc displacement. We collected SF cells from all patients during therapeutic arthrocentesis. The infiltrating cells from TMJ SF were cultured, differentiated into tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and examined bone resorption activities. We also investigated factors related to osteoclast induction of SF, using ELISA procedures. Osteoclast-like cells were induced from the SF cells obtained from all patients with condylar fractures. These multinucleated giant cells were positive for TRAP and actin, and had the ability to absorb dentin slices. The levels of macrophage colony-stimulating factor (M-CSF), prostaglandin E2 (PGE2), soluble form of receptor activator of nuclear factor kappa-B ligand (sRANKL) and osteoprotegerin (OPG), in SF samples from the patients, were significantly higher than in the controls. These findings indicate that bone resorption activities in SF from patients with mandibular condyle fractures were upregulated and may participate in the pathogenesis and wound healing.

Disseminated Intravascular Coagulation after Surgery for Facial Injury

A case of disseminated intravascular coagulation (DIC) presenting after surgery for facial trauma associated with multiple facial bone fractures is described. With regard to the oral and maxillofacial region, DIC has been described in the literature following head trauma, infection, and metastatic disease. Until now, only 5 reports have described DIC after surgery for facial injury. DIC secondary to facial injury is thus rare. The patient in this case was young and had no medical history. Preoperative hemorrhage or postoperative septicemia may thus induce DIC.

A Case of Simultaneous Unilateral Anterior and Posterior Stafne Bone Defects

Stafne bone defects (SBDs) are asymptomatic mandibular lingual bone depressions mainly caused by soft tissue inclusions. The most common form of SBDs is posterior; the anterior variant of SBD is relatively uncommon. Although posterior SBD is easily diagnosed by the unique location on radiography, anterior SBD is sometimes misdiagnosed and confused with other pathological entities owing to the location. We report herein a case of simultaneous unilateral anterior and posterior SBDs. In the present case, definitive diagnosis for the anterior mandibular cavity was unclear, as in reported cases. Surgical exploration was thus performed for the lesion in the anterior mandibular cavity. Pathologic examination of the removed tissue showed salivary gland with chronic inflammation. Postoperatively, no functional disturbance has been observed. Management of the posterior SBD was conservative, with radiographic follow-up. To the best of our knowledge, this represents the first report of simultaneous unilateral anterior and posterior SBDs.

Three-Dimensional Printing Model as a Tool to Assist in Surgery for Large Mandibular Tumour: a Case Report

ABSTRACT Objectives Recently, three-dimensional printing models based on preoperative computed tomography and magnetic resonance imaging images have been widely used in medical fields. This study presents an effective use of the three-dimensional printing model in exploring complex spatial relationship between the tumour and surrounding tissue and in simulation surgery based planning of the operative procedure. Material and Methods The patient was a 7-year-old boy with ameloblastic fibro-odontoma. Prior to surgery, a hybrid three-dimensional printing model consisting of the jaw bone, the tumour and the inferior alveolar nerve was fabricated. After the simulation surgery based on this model, enucleation of the tumour, leaving tooth 46 intact (Universal Numbering System by ADA) safe, was planned. Results Enucleation of the tumour was successfully carried out. One year later, healing was found to be satisfactory both clinically and radiographically. Conclusions The study presented an effective application of a novel hybrid three-dimensional printing model composed of hard and soft tissues. Such innovations can bring significant benefits, especially to the field of oncological surgery.

Successful Outcome of Low-Dose S-1 Used to Treat Buccal Squamous Cell Carcinoma

This case report describes an 86-year-old woman with dormant right buccal squamous cell carcinoma who was able to maintain a reasonable quality of life after being treated with oral low-dose S-1 (80 mg/day). The treatment regimen started in April 2014 and consisted of two weeks of S-1 followed by a one-week interval. The patient remains on this regimen while maintaining her quality of life and she has been under follow-up as an outpatient for 36 months. The outcomes for this patient indicated that low-dose S-1 is a valid anticancer therapy that may help maintain quality of life for some patients with incurable or dormant cancers.