Reconstruction of rabbit mandibular bone defects using carbonate apatite honeycomb blocks with an interconnected porous structure.

Carbonate apatite (CO3Ap) granules are useful as a bone substitute because they can be remodeled to new natural bone in a manner that conforms to the bone remodeling process. However, reconstructing large bone defects using CO3Ap granules is difficult because of their granular shape. Therefore, we fabricated CO3Ap honeycomb blocks (HCBs) with continuous unidirectional pores. We aimed to elucidate the tissue response and availability of CO3Ap HCBs in the reconstruction of rabbit mandibular bone defects after marginal mandibulectomy. The percentages of the remaining CO3Ap area and calcified bone area (newly formed bone) were estimated from the histological images. CO3Ap area was 49.1 ± 4.9%, 30.3 ± 3.5%, and 25.5 ± 8.8%, whereas newly formed bone area was 3.0 ± 0.6%, 24.3 ± 3.3%, and 34.7 ± 4.8% at 4, 8, and 12 weeks, respectively, after implantation. Thus, CO3Ap HCBs were gradually resorbed and replaced by new bone. The newly formed bone penetrated most of the pores in the CO3Ap HCBs at 12 weeks after implantation. By contrast, the granulation tissue scarcely invaded the CO3Ap HCBs. Some osteoclasts invaded the wall of CO3Ap HCBs, making resorption pits. Furthermore, many osteoblasts were found on the newly formed bone, indicating ongoing bone remodeling. Blood vessels were also formed inside most of the pores in the CO3Ap HCBs. These findings suggest that CO3Ap HCBs have good osteoconductivity and can be used for the reconstruction of large mandibular bone defects. The CO3Ap HCB were gradually resorbed and replaced by newly formed bone.

Maxillary Sinus Floor Augmentation Using Low-Crystalline Carbonate Apatite Granules With Simultaneous Implant Installation: First-in-Human Clinical Trial.

PURPOSE: Carbonate apatite (CO3Ap), an inorganic component of human bone, can be fabricated in chemically pure form from calcium carbonate block via a dissolution-precipitation reaction. A first-in-human clinical trial was conducted in which low-crystalline CO3Ap granules were evaluated for safety and efficacy in sinus floor augmentation and simultaneous implant installation. MATERIALS AND METHODS: Procedures were performed in 8 patients (9 implants) with 2 granule sizes: small (300 to 600 µm) and medium (600 to 1,000 µm). Panoramic radiographic assessment was performed immediately after augmentation, 7 ± 2 months after augmentation, 6 ± 2 months after prosthetic loading, and 12 ± 2 months after prosthetic loading. RESULTS: Postoperative healing was uniformly uneventful, with no abnormal bleeding, pain, or swelling, and all implants achieved successful osseointegration. The mean residual maxillary molar bone height was 5.2 ± 0.8 mm preoperatively and increased to 14.0 ± 1.9 mm after augmentation. Implants 9.0 to 11.5 mm in length were placed. The post-augmentation height decreased to 12.4 ± 1.3 mm at 7 ± 2 months; after prosthetic loading, it decreased to 11.9 ± 0.8 mm at 6 ± 2 months and 11.7 ± 0.6 mm at 12 ± 2 months. No abnormal bone resorption of the augmented areas was observed, and bone height supporting the implants was maintained. The overall implant survival rate was 100%, with no implant failures or complications during the first year. CONCLUSIONS: Low-crystalline CO3Ap granules were useful and safe for sinus floor augmentation and simultaneous implant installation, providing a promising bone substitute for dental implant surgery.

Compositional and histological comparison of carbonate apatite fabricated by dissolution-precipitation reaction and Bio-Oss®.

Carbonate apatite (CO3Ap) is an inorganic component of bone. This study aimed to compare the composition and tissue response to of CO3Ap (CO3Ap-DP) fabricated by the dissolution-precipitation reaction using calcite as a precursor and Bio-Oss®, which is widely used in orthopedic and dental fields as a synthetic bone substitute. X-ray diffraction and Fourier transform infrared results showed that CO3Ap-DP and Bio-Oss® were both B-type carbonate apatite with low crystallinity. The average sizes of CO3Ap-DP and Bio-Oss® granules were 450 ± 58 and 667 ± 168µ m, respectively, and their carbonate contents were 12.1 ± 0.6 and 5.6 ± 0.1 wt%, respectively. CO3Ap-DP had a larger amount of CO3 than Bio-Oss® but higher crystallinity than Bio-Oss®. When a bone defect made at the femur of rabbits was reconstructed with CO3Ap-DP and Bio-Oss®, CO3Ap-DP granules were partially replaced with bone, whereas Bio-Oss® remained at 8 weeks after implantation. CO3Ap-DP granules elicited a significantly larger amount of new bone formation at the cortical bone portion than Bio-Oss® at 4 weeks after the implantation. The results obtained in the present study demonstrated that CO3Ap-DP and Bio-Oss® showed different behavior even though they were both classified as CO3Ap. The CO3 content in CO3Ap played a more important role than the crystallinity of CO3Ap for replacement to bone and high osteoconductivity.

Prevalence and imaging characteristics of palatine tonsilloliths evaluated on 2244 pairs of panoramic radiographs and CT images.

OBJECTIVES: Palatine tonsilloliths incidentally detected on diagnostic imaging should be differentiated from pathologic calcifications to enable correct diagnosis and treatment. The aim of this study is to clarify the prevalence and imaging characteristics of palatine tonsilloliths on panoramic radiographs. MATERIALS AND METHODS: We retrospectively reviewed 2244 individuals who underwent pairs of consecutive panoramic radiography and computed tomography (CT) of the head and neck region. The imaging characteristics of palatine tonsilloliths on panoramic radiography were compared with the findings from CT, which was considered the gold standard. RESULTS: Tonsilloliths were detected in 300 (13.4 %) and 914 (40.7 %) of the 2244 individuals on panoramic radiographs and CT, respectively. On panoramic radiographs, tonsilloliths were superimposed over the ramus of the mandible at the level coincident with and inferior to the soft palate in 176 (7.8 %) and 90 (4.0 %) individuals, respectively. Tonsilloliths were also superimposed over the surrounding soft tissue inferior to the body of the mandible, postero-inferior to the angle of the mandible, and posterior to the ramus of the mandible in 33 (1.5 %), 26 (1.2 %), and 28 (1.3 %) individuals, respectively. A significant correlation was observed between the detectability on panoramic radiographs and the size (Spearman r = 1.000) and number (Spearman r = 0.991) of tonsilloliths, as revealed by CT images. CONCLUSIONS: The present results suggest that tonsilloliths are commonly detected on panoramic radiographs. Furthermore, they can be superimposed on both the mandible and the surrounding soft tissue. CLINICAL RELEVANCE: Clinicians should include tonsilloliths among the differential diagnoses when calcified bodies are detected on panoramic radiographs.

Effects of low crystalline carbonate apatite on proliferation and osteoblastic differentiation of human bone marrow cells.

Carbonated apatite (CO3Ap) is the inorganic component of bone. We have proposed a new method for the fabrication of CO3Ap blocks based on a dissolution-precipitation method using a synthetic precursor. The aim of this study is to examine the effects of low crystalline CO3Ap on initial cell attachment, proliferation and osteoblastic differentiation of human bone marrow cells (hBMCs) using sintered hydroxyapatite and tissue culture plates as controls. Initial cell attachment and proliferation were assessed with a MTT assay. Expression of osteoblastic markers was examined by reverse transcription-polymerase chain reaction. XRD and FT-IR results showed formation of B-type carbonate apatite with lower crystallinity. No difference was observed for initial cell attachment between HAp and CO3Ap discs. hBMSC attached more significantly on tissue culture plate than on HAp and CO3Ap discs. The number of cells on HAp was higher than that on CO3Ap until day 7, after which the number of cells was similar. hBMSC proliferated more significantly on tissue culture plate than on HAp and CO3Ap discs. In contrast, hBMCs incubated on CO3Ap demonstrated much higher expression of osteoblastic markers of differentiation, such as type I collagen, alkaline phosphatase, osteopontin and osteocalcin, than hBMCs on HAp. On the tissue culture plate, they were not any change throughout the culture period. These results demonstrated that low crystalline CO3Ap exhibit higher osteoinductivity than HAp.

Prevalence and imaging characteristics of palatine tonsilloliths detected by CT in 2,873 consecutive patients.

AIM: Tonsilloliths are calcified structures that develop in tonsillar crypts. They are commonly detected in daily clinical practice. The prevalence of tonsilloliths was 16 to 24% in previous reports, but it is inconsistent with clinical experience. The aim of this study is to clarify the prevalence, number, and size distribution of tonsilloliths using computed tomography (CT) in a relatively large number of patients. MATERIALS AND METHODS: We retrospectively reviewed the scans of 2,873 patients referred for CT examinations with regard to tonsilloliths. RESULTS: Palatine tonsilloliths were found in 1,145 out of 2,873 patients (39.9%). The prevalence of tonsilloliths increased with age, and most commonly in patients of ages 50-69. The prevalence in the 30s and younger was statistically lower than in the 40s and older (P < 0.05). The number of tonsilloliths per palatine tonsil ranged from one to 18. The size of the tonsilloliths ranged from 1 to 10 mm. For the patients with multiple CT examinations,the number of tonsilloliths increased in 51 (3.9%) and decreased in 84 (6.5%) of the tonsils. CONCLUSIONS: As palatine tonsilloliths are common conditions, screenings for tonsilloliths during the diagnosis of soft tissue calcifications should be included in routine diagnostic imaging.

Pollen Food Allergy Syndrome Caused by Japanese Radish: A Case Report.

Pollen food allergy syndrome (PFAS) is a food allergy that manifests as hypersensitivity symptoms of the oropharyngeal mucosa on ingesting specific foods, and findings resemble herpetic gingivostomatitis. Few reports of PFAS caused by consuming radishes are found in the literature. A 31-year-old man presented to our department with stomatitis and pharyngeal pain. He had no history of allergies. Herpetic gingivostomatitis was suspected. He was admitted to the emergency room a few days later complaining of oral and epigastric pain. Symptoms were similar to those reported previously. He reported frequently consuming raw Japanese radish (Raphans sativus L.) which gave rise to his symptoms. Japanese radish was suspected as the allergen. The skin-prick test confirmed the diagnosis of PFAS. PFAS can be diagnosed easily once the food-causing symptoms are identified. Upon encountering widespread erosion in the oral cavity, it is essential to consider PFAS as the possible cause.

Radiomics analysis of [18F]-fluoro-2-deoxyglucose positron emission tomography for the prediction of cervical lymph node metastasis in tongue squamous cell carcinoma.

OBJECTIVES: This study aimed to create a predictive model for cervical lymph node metastasis (CLNM) in patients with tongue squamous cell carcinoma (SCC) based on radiomics features detected by [18F]-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET). METHODS: A total of 40 patients with tongue SCC who underwent 18F-FDG PET imaging during their first medical examination were enrolled. During the follow-up period (mean 28 months), 20 patients had CLNM, including six with late CLNM, whereas the remaining 20 patients did not have CLNM. Radiomics features were extracted from 18F-FDG PET images of all patients irrespective of metal artifact, and clinicopathological factors were obtained from the medical records. Late CLNM was defined as the CLNM that occurred after major treatment. The least absolute shrinkage and selection operator (LASSO) model was used for radiomics feature selection and sequential data fitting. The receiver operating characteristic curve analysis was used to assess the predictive performance of the 18F-FDG PET-based model and clinicopathological factors model (CFM) for CLNM. RESULTS: Six radiomics features were selected from LASSO analysis. The average values of the area under the curve (AUC), accuracy, sensitivity, and specificity of radiomics analysis for predicting CLNM from 18F-FDG PET images were 0.79, 0.68, 0.65, and 0.70, respectively. In contrast, those of the CFM were 0.54, 0.60, 0.60, and 0.60, respectively. The 18F-FDG PET-based model showed significantly higher AUC than that of the CFM. CONCLUSIONS: The 18F-FDG PET-based model has better potential for diagnosing CLNM and predicting late CLNM in patients with tongue SCC than the CFM.

Analysis of the sublingual artery using contrast-enhanced computed tomography.

INTRODUCTION: This in vivo study aimed to clarify the position of the sublingual artery (SLA) relative to the mandibular bone and to infer the potential risk for injury during dental implant surgery. METHODS: Contrast-enhanced computed tomography images of the mouth of 50 edentulous patients (100 sides) treated at Tokushima University Hospital were reviewed. Curved planar reconstructed images perpendicular to the alveolar ridge were processed and classified into molar, premolar, canine, and incisor regions. The SLA and its branches were identified, and the distance from the mandible to the SLA was measured. RESULTS: The SLA was located close to the mandible (<2 mm) in the molar, premolar, canine, and incisor segments in 12.0% (95% confidence interval 5.6%-18.4%), 20.6% (12.6%-28.7%), 30.5% (21.3%-39.8%), and 41.8% (28.8%-54.9%) cases, respectively. The SLA was located within ±3 mm craniocaudally to the upper wall of the mandibular canal in the molar and premolar regions in 50% of cases and within ±5 mm craniocaudally to the mylohyoid ridge in the canine and incisor regions in the other cases, with no sex or age-related differences. The vertical distance from the alveolar ridge to the SLA was influenced by sex and age owing to alveolar resorption, indicating that the alveolar ridge is not a reliable reference for predicting SLA position. CONCLUSIONS: As the risk of SLA injury always exist during dental implant placement and there is no way to confirm the SLA pathways in a patient, clinicians must avoid injuring the sublingual soft tissue.

Osteoclast behaviors on the surface of deproteinized bovine bone mineral and carbonate apatite substitutes in vitro.

The present study investigated the osteoclast differentiation potential and paracrine effects of osteoclasts on osteoblast differentiation when the cells were cultured directly on two bone substitutes (BSs): deproteinized bovine bone mineral (DBBM) and carbonate apatite (CO3 Ap). Human primary osteoclasts cultured on the BSs were assessed by tartrate-resistant acid phosphatase (TRAP) and actin ring staining. Thereafter, the mRNA levels of osteoclastic differentiation markers were quantified by real-time PCR. Osteoblast behaviors in response to conditioned media collected from osteoclast cultures were investigated. Interestingly, mature osteoclasts were occasionally observed on the surface of the CO3 Ap granules, whereas very few and small osteoclasts were observed on DBBM. Similarly, real-time PCR analysis showed higher mRNA levels of osteoclast markers, including cathepsin K and TRAP, in the cells cultured on CO3 Ap than in those cultured on DBBM. Furthermore, compared to DBBM, CO3 Ap promoted osteoblast differentiation in human primary osteoblasts, whereas few paracrine effects of osteoclasts cultured with either BS were observed on the osteoblast differentiation potential. These limited results showed that CO3 Ap provided a favorable surface for osteoclast differentiation, as well as osteoblasts, compared to DBBM in vitro.

miR-155-5p can be involved in acquisition of osseointegration on titanium surface.

Dental implants made of titanium are commonly used. Although titanium implants succeed by osseointegration with bone, the detailed molecular mechanism of osseointegration is unclear. To clarify the involvement of microRNA (miRNA) in the acquisition of osseointegration on titanium, here we compared the miRNA expression profiles of mouse osteoblast-like cells (MC3T3-E1) cultured on titanium-, gold-, and stainless steel-coating glass dishes by microarray analysis. Three kinds of metals, namely titanium, gold, and stainless steel, were coated on the surface of the glass dishes by sputtering with similar roughness and shape of their surface. After MC3T3-E1 cells were cultured on the dishes without coating or coating with titanium, gold, or stainless steel for 6 h, total RNA was extracted, and miRNA expression was analyzed by microarray. To confirm the expression of the selected miRNA during osteogenic differentiation of MC3T3-E1 cells, real-time PCR analysis was performed. Furthermore, the effects of selected miRNA were examined by ectopic overexpression in MC3T3-E1 cells. The microarray analysis revealed that the expressions of miR-155-5p and miR-7023-3p were significantly increased in MC3T3-E1 cells cultured on titanium-coating glass dishes, compared to non-coating, gold-, and stainless steel-coating glass dishes. Interestingly, miR-155-5p was upregulated during osteogenic differentiation of MC3T3-E1 cells. Furthermore, overexpression of miR-155-5p enhanced the expression of Runx2 and Col1a1. In this study, miR-155-5p may be involved in the acquisition of osseointegration on titanium implant via upregulating osteogenic differentiation-related genes.

Association of PD-L1 and ZEB-1 expression patterns with clinicopathological characteristics and prognosis in oral squamous cell carcinoma.

Programmed cell death-1 (PD-1) and its ligand programmed cell death 1 ligand 1 (PD-L1) are immune checkpoint inhibitors that play an important role in the host immune avoidance mechanism of tumors. The relationship between PD-L1 expression and malignancy has been reported in various types of cancer, such as lung and gastric cancer. In addition, epithelial-mesenchymal transition (EMT) of cancer cells is deeply involved in the invasion and metastasis of cancer. It has been reported that zinc finger E-box binding homeobox 1 (ZEB-1), an EMT inducer, contributes to metastasis in pancreatic and colon cancer. The present study aimed to investigate the relationship between the expression patterns of two markers, PD-L1 and ZEB-1, and clinicopathological characteristics and prognosis of oral squamous cell carcinoma (OSCC). Biopsy or surgical excision specimens from 169 patients with OSCC were used in the present study. Immunohistochemical staining with monoclonal anti-PD-L1 antibody and anti-ZEB-1 antibody was conducted. Cases with >1% tumor cells positive for PD-L1 and those with >10% tumor cells positive for ZEB-1 were considered positive, respectively. The findings revealed that individual expression of PD-L1 and ZEB-1 in OSCC was not associated with tumor size, degree of differentiation or Yamamoto-Kohama invasion pattern classification. However, co-expression of PD-L1 and ZEB-1 was associated with higher cervical lymph node metastasis and a lower survival rate. In conclusion, the results of the present study indicated that co-expression of PD-L1 and ZEB-1 could serve as a potential marker for the prognosis of patients with OSCC.

Prevalence of and risk factors for postoperative complications after lower third molar extraction: A multicenter prospective observational study in Japan.

Lower third molar extraction is the most common surgical treatment among routine dental and oral surgical procedures. while the surgical procedures for lower third molar extraction are well established, the difficulty of tooth extraction and the frequency of postoperative complications differ depending on the patient's background. To establish a management protocol for the lower third molars, the prevalence of and risk factors for postoperative complications after lower third molar extraction were investigated in a large number of Japanese patients in a multicenter prospective study. During 6 consecutive months in 2020, 1826 lower third molar extractions were performed at the 20 participating institutions. The medical records of the patients were reviewed, and relevant data were extracted. The prevalence of and risk factors for postoperative complications were analyzed. The prevalence of postoperative complications after lower third molar extraction was 10.0%. Multivariate analysis indicated that age (≤32 vs >32, odds ratio [OR]: 1.428, 95% confidence interval [95% CI]: 1.040-1.962, P < .05), the radiographic anatomical relationship between the tooth roots and mandibular canal (overlapping of the roots and canal vs no close anatomical relationship between the roots and the superior border of the canal, OR: 2.078, 95% CI: 1.333-3.238, P < .01; overlapping of the roots and canal vs roots impinging on the superior border of the canal, OR: 1.599, 95% CI: 1.050-2.435, P < .05), and impaction depth according to the Pell and Gregory classification (position C vs position A, OR: 3.7622, 95% CI: 2.079-6.310, P < .001; position C vs position B, OR: 2.574, 95% CI: 1.574-4.210, P < .001) are significant independent risk factors for postoperative complications after lower third molar extraction. These results suggested that higher age and a deeply impacted tooth might be significant independent risk factors for postoperative complications after lower third molar extraction.

[Evaluation of combination chemotherapy with oral S-1 administration followed by docetaxel by superselective intra-arterial infusion for patients with oral squamous cell carcinomas].

The purpose of this study was to evaluate the effectiveness and adverse events of combination chemotherapy with oral S-1 administration following docetaxel (DOC) treatment by superselective intra-arterial infusion as neo-adjuvant chemotherapy (NAC) for patients with oral squamous cell carcinoma. Thirteen patients were enrolled in this study (9 men and 4 women, with a mean age of 61. 0 years). All patients were given S-1 65mg/m(2) per day for 14 days, and DOC 40-50mg/m(2) by intraarterial infusion was administered. The locoregional response evaluated 3 weeks after administration was 100%, including a 69. 2% complete response. According to Oboshi and Shimosato's classification, histological evaluation of surgical specimens revealed that 3 cases were Grade II a, 4 cases Grade II b, 1 case Grade IV a, and 4 cases Grade IV c. The severe side effects were neutropenia and cerebral infarction. The present study suggests that combination chemotherapy with S-1 and DOC by superselective intra-arterial infusion would be an effective and safe regimen in NAC for oral squamous cell carcinomas.

The Soluble Factor from Oral Cancer Cell Lines Inhibits Interferon-γ Production by OK-432 via the CD40/CD40 Ligand Pathway.

(1) Background: OK-432 is a penicillin-killed, lyophilized formulation of a low-toxicity strain (Su) of Streptococcus pyogenes (Group A). It is a potent immunotherapy agent for several types of cancer, including oral cancer. We previously showed that (i) OK-432 treatment induces a high amount of IFN-? production from peripheral blood mononuclear cells (PBMCs), and (ii) conditioned medium (CM) from oral cancer cells suppresses both the IFN-? production and cytotoxic activity of PBMCs driven by OK-432. The aim of this study was to determine the inhibitory mechanism of OK-432-induced IFN-? production from PBMCs by CM. (2) Methods: We performed cDNA microarray analysis, quantitative RT-PCR, and ELISA to reveal the inhibitory mechanism of CM. (3) Results: We found that CD40 plays a key role in IFN-? production via IL-12 production. Although OK-432 treatment upregulated the expression levels of the IL-12p40, p35, and CD40 genes, CM from oral cancer cells downregulate these genes. The amount of IFN-? production by OK-432 treatment was decreased by an anti-CD40 neutralizing antibody. (4) Conclusions: Our study suggests that uncertain soluble factor(s) produced from oral cancer cells may inhibit IFN-? production from PBMCs via suppressing the CD40/CD40L-IL-12 axis.

Staged Sinus Floor Elevation Using Novel Low-Crystalline Carbonate Apatite Granules: Prospective Results after 3-Year Functional Loading.

The aim of this study was to evaluate clinical outcomes of staged sinus floor elevation (SFE) using novel low-crystalline carbonate apatite (CO3Ap) granules. Patients who needed SFE for implant placement were recruited into this clinical trial. A staged procedure (lateral window technique using CO3Ap granules, followed by implant placement after 7 ± 2 months) was employed in 13 patients. Bone-height increase and insertion torque values (ITVs) were assessed along with histological evaluation. The survival and success rates of 3-year functioning implants were also evaluated. Mean of bone-height increase after SFE using CO3Ap granules was 7.2 ± 2.5 mm and this increase allowed implant placement in all cases (17 implants). Mean of ITV was 25.1 ± 13.2 Ncm and primary stability was achieved successfully in all cases. Histological analyses revealed mature new bone formation (36.8 ± 17.3%) and residual CO3Ap granules (16.2 ± 10.1%) in the compartment after SFE. The survival and success rates after 3-year functional loading were 100% and no complications were found. These results clearly indicate the clinical usefulness of CO3Ap granules for SFE.

Histological comparison of three apatitic bone substitutes with different carbonate contents in alveolar bone defects in a beagle mandible with simultaneous implant installation.

Since bone apatite is a carbonate apatite containing carbonate in an apatitic structure, carbonate content may be one of the factors governing the osteoconductivity of apatitic bone substitutes. The aim of this study was to evaluate the effects of carbonate content on the osteoconductivity of apatitic bone substitutes using three commercially available bone substitutes for the reconstruction of alveolar bone defects of a beagle mandible with simultaneous dental implant installation. NEOBONE, Bio-Oss, and Cytrans that contain 0.1, 5.5, and 12.0 mass% of carbonate, respectively, were used in this study. The amount of newly formed bone in the upper portion of the alveolar bone defect of the beagle's mandible was 0.7, 6.6, and 39.4% at 4 weeks after surgery and 4.7, 39.5, and 75.2% at 12 weeks after surgery for NEOBONE, Bio-Oss, and Cytrans, respectively. The results indicate that bone-to-implant contact ratio was the largest for Cytrans. Additionally, the continuity of the alveolar ridge was restored in the case of Cytrans, whereas the continuity of the alveolar ridge was not sufficient when using NEOBONE and Bio-Oss. Both Cytrans and Bio-Oss that have a relatively larger carbonate content in their apatitic structure was resorbed with time. We concluded that carbonate content is one of important factors governing the osteoconductivity of apatitic bone substitutes.

Effects of acidic calcium phosphate concentration on setting reaction and tissue response to ß-tricalcium phosphate granular cement.

Beta-tricalcium phosphate granular cement (ß-TCP GC), consisting of ß-TCP granules and an acidic calcium phosphate (Ca-P) solution, shows promise in the reconstruction of bone defects as it sets to form interconnected porous structures, that is, ß-TCP granules are bridged with dicalcium phosphate dihydrate (DCPD) crystals. In this study, the effects of acidic Ca-P solution concentration (0-600 mmol/L) on the setting reaction and tissue response to ß-TCP GC were investigated. The ß-TCP GC set upon mixing with its liquid phase, based on the formation of DCPD crystals, which bridged ß-TCP granules to one another. Diametral tensile strength of the set ß-TCP GC was relatively the same, at ∼0.6 MPa, when the Ca-P concentration was 20-600 mmol/L. Due to the setting ability, reconstruction of the rat's calvarial bone defect using ß-TCP GC with 20, 200, and 600 mmol/L Ca-P solution was much easier compared to that with ß-TCP granules without setting ability. Four weeks after the reconstruction, the amount of new bone was the same, ∼17% in both ß-TCP GC and ß-TCP granules groups. Cellular response to ß-TCP granules and ß-TCP GC using the 20 mmol/L acidic Ca-P solution was almost the same. However, ß-TCP GC using the 200 and 600 mmol/L acidic Ca-P solution showed a more severe inflammatory reaction. It is concluded, therefore, that ß-TCP GC, using the 20 mmol/L acidic Ca-P solution, is recommended as this concentration allows surgical techniques to be performed easily and provides good mechanical strength, and the similar cellular response to ß-TCP granules. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:22-29, 2020.

Fabrication of porous carbonate apatite granules using microfiber and its histological evaluations in rabbit calvarial bone defects.

Carbonate apatite (CO3 Ap) granules are known to show good osteoconductivity and replaced to new bone. On the other hand, it is well known that a porous structure allows bone tissue to penetrate its pores, and the optimal pore size for bone ingrowth is dependent on the composition and structure of the scaffold material. Therefore, the aim of this study was to fabricate various porous CO3 Ap granules through a two-step dissolution-precipitation reaction using CaSO4 as a precursor and 30-, 50-, 120-, and 205-µm diameter microfibers as porogen and to find the optimal pore size of CO3 Ap. Porous CO3 Ap granules were successfully fabricated with pore size 8.2-18.7% smaller than the size of the original fiber porogen. Two weeks after the reconstruction of rabbit calvarial bone defects using porous CO3 Ap granules, the largest amount of mature bone was seen to be formed inside the pores of CO3 Ap (120) [porous CO3 Ap granules made using 120-µm microfiber] followed by CO3 Ap (50) and CO3 Ap (30). At 4 and 8 weeks, no statistically significant difference was observed based on the pore size, even though largest amount of mature bone was formed in case of CO3 Ap (120). It is concluded, therefore, that the optimal pore size of the CO3 Ap is that of CO3 Ap (120), which is 85 µm.

Vesnarinone downregulates CXCR4 expression via upregulation of Krüppel-like factor 2 in oral cancer cells.

BACKGROUND: We have demonstrated that the stromal cell-derived factor-1 (SDF-1; CXCL12)/CXCR4 system is involved in the establishment of lymph node metastasis in oral squamous cell carcinoma (SCC). Chemotherapy is a powerful tool for the treatment of oral cancer, including oral SCC; however, the effects of chemotherapeutic agents on the expression of CXCR4 are unknown. In this study, we examined the expression of CXCR4 associated with the chemotherapeutic agents in oral cancer cells. RESULTS: The expression of CXCR4 was examined using 3 different chemotherapeutic agents; 5-fluorouracil, cisplatin, and vesnarinone (3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2-(1H)-quinolinone) in B88, a line of oral cancer cells that exhibits high levels of CXCR4 and lymph node metastatic potential. Of the 3 chemotherapeutic agents that we examined, only vesnarinone downregulated the expression of CXCR4 at the mRNA as well as the protein level. Vesnarinone significantly inhibited lymph node metastasis in tumor-bearing nude mice. Moreover, vesnarinone markedly inhibited 2.7-kb human CXCR4 promoter activity, and we identified the transcription factor, Krüppel-like factor 2 (KLF2), as a novel vesnarinone-responsive molecule, which was bound to the CXCR4 promoter at positions -300 to -167 relative to the transcription start site. The forced-expression of KLF2 led to the downregulation of CXCR4 mRNA and impaired CXCR4 promoter activity. The use of siRNA against KLF2 led to an upregulation of CXCR4 mRNA. CONCLUSION: These Results indicate that vesnarinone downregulates CXCR4 via the upregulation of KLF2 in oral cancer.