Clinicians should include tonsilloliths among the differential diagnoses when calcified bodies are detected on panoramic radiographs.

In general, allergic risk of titanium material is smaller than that of other metal materials. However, we suggest that pre-implant patients should be asked about a history of hypersensitivity reactions to metals, and patch testing should be recommended to patients who have experienced such reactions.

Three commercially available artificial bone substitutes with different compositions, hydroxyapatite (HAp; Neobone®), carbonate apatite (CO3Ap; Cytrans®), and β-tricalcium phosphate (β-TCP; Cerasorb®), were compared with respect to their physical properties and tissue response to bone, using hybrid dogs. Both Neobone® (HAp) and Cerasorb® (β-TCP) were porous, whereas Cytrans® (CO3Ap) was dense. Crystallite size and specific surface area (SSA) of Neobone® (HAp), Cytrans® (CO3Ap), and Cerasorb® (β-TCP) were 75.4 ± 0.9 nm, 30.8 ± 0.8 nm, and 78.5 ± 7.5 nm, and 0.06 m2/g, 18.2 m2/g, and 1.0 m2/g, respectively. These values are consistent with the fact that both Neobone® (HAp) and Cerasorb® (β-TCP) are sintered ceramics, whereas Cytrans® (CO3Ap) is fabricated in aqueous solution. Dissolution in pH 5.3 solution mimicking Howship’s lacunae was fastest in CO3Ap (Cytrans®), whereas dissolution in pH 7.3 physiological solution was fastest in β-TCP (Cerasorb®). These results indicated that CO3Ap is stable under physiological conditions and is resorbed at Howship’s lacunae. Histological evaluation using hybrid dog mandible bone defect model revealed that new bone was formed from existing bone to the center of the bone defect when reconstructed with CO3Ap (Cytrans®) at week 4. The amount of bone increased at week 12, and resorption of the CO3Ap (Cytrans®) was confirmed. β-TCP (Cerasorb®) showed limited bone formation at week 4. However, a larger amount of bone was observed at week 12. Among these three bone substitutes, CO3Ap (Cytrans®) demonstrated the highest level of new bone formation. These results indicate the possibility that bone substitutes with compositions similar to that of bone may have properties similar to those of bone.

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.

TLR4 and MD-2 may mediate OK-432-induced anticancer immunity.

Carbonate apatite (COAp) is an inorganic component of bone. This study aimed to compare the composition and tissue response to of COAp (COAp-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 COAp-DP and Bio-Oss® were both B-type carbonate apatite with low crystallinity. The average sizes of COAp-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. COAp-DP had a larger amount of CO than Bio-Oss® but higher crystallinity than Bio-Oss®. When a bone defect made at the femur of rabbits was reconstructed with COAp-DP and Bio-Oss®, COAp-DP granules were partially replaced with bone, whereas Bio-Oss® remained at 8 weeks after implantation. COAp-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 COAp-DP and Bio-Oss® showed different behavior even though they were both classified as COAp. The CO content in COAp played a more important role than the crystallinity of COAp for replacement to bone and high osteoconductivity.

BACKGROUND Osteoclastic bone resorption is an important step in bone invasion in several malignancies. Although interleukin (IL)‐6 accelerates osteoclastic bone resorption, it remains unclear whether IL‐6 may be involved in bone invasion of oral cancer. METHODS The pit formation assay with calf femur‐derived bone slices was performed to examine the bone‐resorbing activity of osteoclasts and cancer cells. The chemotaxis activity of the culture media was analyzed by the use of Boyden chamber technique. Nude mice, which were inoculated with IL‐6–producing oral cancer cells into masseter, were treated with anti–IL‐6 neutralizing antibody, and mandibular‐bone invasion of the cells was assessed. RESULTS BHY, a bone‐invasive oral cancer cell line, but not HNT, a noninvasive cell line, produced large amounts of IL‐6. In a pit formation assay, addition of conditioned medium (CM) derived from BHY but not HNT increased osteoclastic bone resorption, and the effects were inhibited by anti–IL‐6 antibody. BHY‐secreted IL‐6 showed significant chemotaxis activity for osteoclasts. Of note, CM from the cocultivation of osteoclasts and BHY markedly enhanced the cancer cell migration, and the chemotaxis activity was significantly reduced when anti–IL‐6 antibody was added into the coculture and then CM were collected, but not when the antibody was added into the CM after they were collected. Furthermore, treatment with anti–IL‐6 antibody almost completely inhibited mandibular bone invasion of BHY in nude mice. CONCLUSIONS These results strongly suggest that IL‐6 secreted by oral cancer cells plays a significant role in bone invasion. Cancer 2000;89:1966–75. © 2000 American Cancer Society.

Abstract. Cancer stem cells (CSCs) exhibit self-replication, self-differentiation, drug resistance and immune evasion activities. In recent years CSCs have become increasingly important for the treatment of malignant tumors. CSCs express specific markers, including cluster of differentiation (CD)44, CD44 variant 9 (CD44v9), ATP-binding cassette sub-family G member 2 (ABCG2), CD24, B lymphoma Mo-MLV insertion region 1 homolog (BMI-1) and aldehyde dehydrogenase 1 (ALDH1). However, the prognostic value of their expression in patients with oral squamous cell carcinoma (OSCC) are not well known. The present study evaluated these markers in stage I and II patients with OSCC and examined the association between T classification, histological differentiation, classification of invasion mode, lymph node metastasis and disease-free survival rate. Tissue specimens were obtained from 70 patients with stage I or II OSCC following either surgery or biopsy. Immunohistochemistry was performed and positive staining was defiend as 10% positive cells. CD44 and CD44v9 expressions were strongly detected in all OSCC tissues compared with normal epithelial cells. A total of 22 (31.4%) cases expressed ABCG2 and there was a significant association between ABCG2 expression and invasion. A total of 41 cases (59.0%) expressed CD24 and there was a significant association between CD24 expression and invasion. A total of 33 cases (47.1%) expressed BMI-1 and there was a significant association between BMI-1 expression and the disease-free survival rate. A total of 18 cases (25.7%) expressed ALDH1.Although there was no association between ALDH1 expression and T classification, there were significant associations between ALDH1 expression and histological differentiation, invasion mode, metastasis and the disease-free survival rate. Multivariate analysis revealed that ALDH1 expression was the only prognostic factor for disease-free survival rate. The results of the present study suggest that the positivity of ALDH1 detected in patients with OSCC correlates with the number of cells undergoing epithelial mesenchymal transition and metastasis. These findings indicated that the expression of ALDH1 may be an effective prognostic marker indicating the survival of patients with stage I and II OSCC. IntroductionCancer stem cells (CSCs) are functionally defined by their extensive self-renewal capacity. CSC confers increased radioand chemoresistance in tumors, resulting in tumor recurrence and metastatic spread. Therefore, identification of the regulators that control the tumorigenic potential of CSCs might provide new therapeutic strategies against CSCs to improve cancer treatment. The CSC theory suggests that only a few cancer cells with a capacity for high tumorigenicity, self-renewal, and differentiation are responsible for the maintenance and growth of tumors. Similar to normal tissue stem cells, CSCs can also exist within a supportive niche (1).Oral squamous cell carcinoma (OSCC) patients in stage I and II are mainly treated by surgery and almost all...