Computed Tomographic Analysis of the Mandibular Body and Ramus in Japanese Patients: Relevance to Bone Harvesting From the Mandibular Ramus.

PURPOSE: The aims of this study were to use computed tomography (CT) imaging to determine the anatomical features of the mandibular body and ramus in Japanese subjects and to relate the findings to bone harvesting from the mandibular ramus. MATERIALS AND METHODS: The mandibles of 100 patients (28 males and 72 females) under dental implant treatment plan were observed on CT imaging (slice thickness, 0.625 mm). The linear distance between the superior aspect of the inferior alveolar nerve canal and the alveolar crest (distance A), the linear distance between the buccal aspect of the inferior alveolar nerve canal and the buccal cortical bone (distance B), the thickest width of the buccal cortical bone (distance C), and the thinnest width of the buccal cortical bone (distance D) were measured in the same coronal plane at 4 specific locations (section 1: the distal aspect of the first molar, section 2: the distal aspect of the second molar, section 3: the 10 mm distal aspect of the second molar, and section 4: the 15 mm distal aspect of the second molar). RESULTS: In the measurement of distance A, the minimum section among the male subjects was section 2 (12.55 ± 3.00 mm), whereas among the females, the minimum section was section 3 (11.82 ± 2.85 mm). In the distance B measurements, the maximum value was at section 2 (males: 6.36 ± 1.33 mm, females: 6.32 ± 1.39 mm) and the minimum value was at section 4 (males: 3.85 ± 1.74 mm, females: 4.75 ± 1.47 mm). Regarding the distance C measurements, the values of all subjects ranged from 3.10 to 4.41 mm, and the distance D values were approximately 2 mm. CONCLUSION: In Japanese patients, a rectangular piece of cortical bone up to 2 mm thickness may be harvested from the ramus, the length of the rectangular graft may approach 26 mm, and the height may be 10 mm for the safest harvesting from the mandibular ramus.

Potential anti-osteoporotic effects of herbal extracts on osteoclasts, osteoblasts and chondrocytes in vitro.

BACKGROUND: Osteoporosis (OP) is one of the most serious diseases in the modern world, and OP patients frequently suffer from fragility fractures in the hip, spine and wrist, resulting in a limited quality of life. Although bisphosphonates (BPs) are the most effective class of anti-bone-resorptive drugs currently available and the most commonly prescribed for the clinical treatment of OP, they are known to cause serious side effects such as bisphosphonate-related osteonecrosis of the jaw. Novel therapeutic materials that can replace the use of BPs have therefore been developed. METHODS: We commenced an institutional collaborative project in which candidates of herbal extracts were selected from more than 400 bioactive herbal products for their potential therapeutic effects not only in OP, but also in oral and skeletal diseases. In the present study, we report on 3 Chinese medical herbal extracts from the root barks of Melia azedarach, Corydalis turtschaninovii, and Cynanchum atratum. RESULTS: All of these extracts inhibited osteoclast proliferation and induced apoptosis by up-regulation of caspase activity and increase of mitochondrial pro-apoptotic proteins expression. Furthermore, the extracts enhanced differentiation, but did not affect proliferation of both osteoblasts and chondrocytes. The osteo-inducible effect was also observed in cultured primary bone marrow cells. CONCLUSIONS: Although these extracts have been utilized in traditional Chinese medicine for hundreds of years, there are no reports to our knowledge, on their therapeutic effects in OP. In this study, we elucidate the potency of these herbal extracts as novel candidates for OP therapy.

[Retracted] Proteasome inhibitor sensitizes oral squamous cell carcinoma cells to TRAIL­mediated apoptosis.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that, in Fig. 4 on p. 650, the same ß­actin bands had apparently been used to show the experimental effects of the proteasome inhibitor MG­132 on c­FLIP in HSC­2 cells in Fig. 4A, and the effects of MG­132 on IAPs in HSC­3 cells in Fig. 4B. In addition, for the fourth lane in the gel showing the effects of MG­132 on c­FLIP in HSC­3 cells, this should have been labelled as '+MG­132 / +TRAIL' (not as '­/­'). Upon contacting the authors in relation to this matter, they could only admit that errors had been made in the preparation of the figure; moreover, they no longer had access to the original data owing to the time that has elapsed since the publication of the paper, and it would be impossible for them to now repeat this experiment. After having considered this matter and in conjunction with a request made by the authors, the Editor of Oncology Reports has decided that this paper should be retracted from the publication. Both the Editor and the authors apologize to the readership for any inconvenience caused. [Oncology Reports 25: 645­652, 2011; DOI: 10.3892/or.2010.1127].

General rules for clinical and pathological studies on oral cancer: a synopsis.

For the doctors and other medical staff treating oral cancers, it is necessary to standardize basic concepts and rules on oral cancers to progress in the treatment, research and diagnosis. Oral cancers are integrated in head and neck cancers and are applied to the general rules on head and neck cancer, but it is considered that more detailed rules based on the characteristics of oral cancers are essential. The objectives of this 'General Rules for Clinical and Pathological Studies on Oral Cancer' are to contribute to the development of the diagnosis, treatment and research of oral cancers based on the correct and useful medical information of clinical, surgical, pathological and image findings accumulated from individual patients at various institutions.

Binding of glyceraldehyde-3-phosphate dehydrogenase to the cis-acting element of structure-anchored repression in ccn2 mRNA.

CCN2/connective tissue growth factor (CTGF) can be induced by hypoxia and promotes tumor angiogenesis. Our previous studies revealed that hypoxia-induced gene expression of human ccn2 mRNA is regulated post-transcriptionally in human chondrosarcoma-derived cell line, HCS-2/8, in which a minimal cis-element, entitled CAESAR, in the 3'-untranslated region (UTR) of ccn2 mRNA and a 35-kDa protein counterpart play an important role by determining the stability of ccn2 mRNA. In the present study, we identified this corresponding protein as glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by utilizing RNA affinity chromatography combined with mass spectrometry. The results of an RNA binding assay revealed the specific binding of GAPDH to this cis-element. To further characterize the interaction between GAPDH and ccn2 mRNA, we examined the roles of redox conditions and glycolytic coenzyme in the binding of GAPDH to the ccn2 mRNA. An oxidizing agent, diamide, abolished the GAPDH-RNA interaction in a concentration-dependent manner; whereas this effect could be reversed by subsequent treatment with 2-mercaptoethanol (2-ME). In addition, nicotinamide-adenine dinucleotide (NAD), a coenzyme of GAPDH, inhibited the GAPDH-RNA binding. Taken together, these findings suggest that the glycolytic enzyme GAPDH regulates the gene expression of ccn2 mRNA in trans by acting as a sensor of oxidative stress and redox signals, leading to CCN2 overexpression under the condition of hypoxia and promotion of angiogenesis.

A coding RNA segment that enhances the ribosomal recruitment of chicken ccn1 mRNA.

CCN1, a member of the CCN family of proteins, plays important physiological or pathological roles in a variety of tissues. In the present study, we initially found a highly guanine-cytosine (GC)-rich region of approximately 200 bp near the 5'-end of the open reading frame, which was always truncated by amplification of the corresponding cDNA region through the conventional polymerase chain reaction. An RNA in vitro folding assay and selective ribonuclease digestion of the corresponding segment of the ccn1 mRNA confirmed the involvement of a stable secondary structure. Subsequent RNA electromobility-shift assays demonstrated the specific binding of some cytoplasmic factor(s) in chicken embryo fibroblasts to the RNA segment. Moreover, the corresponding cDNA fragment strongly enhanced the expression of the reporter gene in cis at the 5'-end, but did not do so at the 3'-end. According to the results of a ribosomal assembly test, the effect of the mRNA segment can predominantly be ascribed to the enhancement of transport and/or entry of the mRNA into the ribosome. Finally, the minimal GC-rich mRNA segment that was predicted and demonstrated to form a secondary structure was confirmed to be a functional regulatory element. Thus, we here uncover a novel dual-functionality of the mRNA segment in the ccn1 open reading frame, which segment acts as a cis-element that mediates posttranscriptional gene regulation, while retaining the information for the amino acid sequence of the resultant protein.

Telomerase-specific virotheranostics for human head and neck cancer.

PURPOSE: Long-term outcomes of patients with squamous cell carcinoma of the head and neck (SCCHN) remain unsatisfactory despite advances in combination of treatment modalities. SCCHN is characterized by locoregional spread and it is clinically accessible, making it an attractive target for intratumoral biological therapies. EXPERIMENTAL DESIGN: OBP-301 is a type 5 adenovirus that contains the replication cassette in which the human telomerase reverse transcriptase promoter drives expression of the E1 genes. OBP-401 contained the replication cassette and the green fluorescent protein (GFP) gene. The antitumor effects of OBP-301 were evaluated in vitro by the sodium 30-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate assay and in vivo in an orthotopic xenograft model. Virus spread into the lymphatics was also orthotopically assessed by using OBP-401. RESULTS: Intratumoral injection of OBP-301 resulted in the shrinkage of human SCCHN tumors orthotopically implanted into the tongues of BALB/c nu/nu mice and significantly recovered weight loss by enabling oral ingestion. The levels of GFP expression following ex vivo infection of OBP-401 may be of value as a positive predictive marker for the outcome of telomerase-specific virotherapy. Moreover, whole-body fluorescent imaging revealed that intratumorally injected OBP-401 could visualize the metastatic lymph nodes, indicating the ability of the virus to traffic to the regional lymphatic area and to selectively replicate in neoplastic lesions, resulting in GFP expression and cell death in metastatic lymph nodes. CONCLUSIONS: These results illustrate the potential of telomerase-specific oncolytic viruses for a novel therapeutic and diagnostic approach, termed theranostics, for human SCCHN.

Inhibition of TGF-beta1 suppresses motility and invasiveness of oral squamous cell carcinoma cell lines via modulation of integrins and down-regulation of matrix-metalloproteinases.

Transforming growth factor (TGF)-beta1 is a multifunctional polypeptide that regulates a variety of cellular processes. Several studies have indicated that it is associated with epithelial-mesenchymal transition, angiogenesis, migration and metastases in many types of malignant tumors. We have used a wound-healing assay and a Matrigel invasion assay to evaluate the effects of TGF-beta1 and TGF-beta receptor I kinase inhibitor (TRI) on the cell motility and invasiveness of the human oral squamous cell carcinoma (OSCC) cell lines SAS-L1 and HSC-3. While TGF-beta1 enhanced the migration and invasion of OSCC cells, TRI significantly suppressed the migration and invasion of these cells. Exogenous TGF-beta1 up-regulated the activity of type IV collagenase (gelatinase A and gelatinase B), whereas TRI down-regulated the activity of these matrix metalloproteinases. Western blot analysis revealed that TGF-beta1 enhanced the expression of alpha5, alphav, beta1, beta6 and alphavbeta3 integrin subunits, and these enhanced integrins were down-regulated by treatment with TRI. These results suggest that the inhibition of TGF-beta1 suppresses motility and invasiveness of OSCC cells via modulation of integrins and matrix-metalloproteinases. Therefore, targeting the TGF-beta1 signaling pathway could be beneficial in the treatment of patients with OSCC.

S-1 mediates the inhibition of lymph node metastasis in oral cancer cells.

S-1, an oral fluorouracil antitumor drug, is composed of three agents: tegafur (FT), 5-chloro-2,4-dihydroxypyridine (CDHP), and potassium oxonate (Oxo). Approximately 50% of oral squamous cell carcinomas (OSCC) exhibit cervical lymph node metastasis. The extent of lymph node involvement is a major determinant in both staging and prognosis of the majority of OSCC. The purpose of this study was to examine the effect of S-1 on the metastatic potential of OSCC cells. We used orthotopic green fluorescence protein (GFP) SAS-L1, in BALB/c nu/nu mice. Mice received oral doses of either 5% hydroxypropylmethylcellulose (HPMC) for control or S-1 (20 mg/kg) and were autopsied at 2 weeks. We also performed in vitro experiments using concomitant 5-fluorouracil (5-FU) and CDHP as a drug model of S-1 to determine the effect of S-1 on OSCC invasion and metastasis. Although 100% (11 of 11) of mice not treated with S-1 showed cervical lymph node metastasis, only 54.4% (6 of 11) of S-1 treated mice demonstrated metastasis. In in vitro experiments, OSCC cells treated with 5-FU and CDHP showed a marked reduction in invasiveness and in adhesion to laminin coated plates. Western blot analysis revealed that treatment with 5-FU and CDHP suppressed expression of integrins alphav, alpha3, alpha6, beta1, beta3, beta4, beta5, and beta6. These results suggest that S-1 inhibits tumor proliferation and lymph node metastasis in OSCC cells. Moreover, expression of integrin subunits and the integrin signal transduction pathway may be closely related to metastasis suppression.

Bisphosphonate-related osteonecrosis of the jaw around dental implants in the maxilla: report of a case.

OBJECTIVE: We describe a patient who developed bisphosphonate (BP)-related osteonecrosis of the jaw (ONJ) around implants in the upper molar area. PATIENTS AND METHODS: The patient was a 54-year-old woman with ulceration of the gum, bone exposure, and severe spontaneous pain around implants in the upper left molar area. She had received BPs intravenously for 2 years to treat bone metastases of breast cancer. She was diagnosed with BP-related ONJ. Sequestrum including implants was resected, and hyperbaric oxygen therapy was performed. Undecalcified ground sections were prepared from the resected bone around the implants and stained with toluidine blue. For the bone around the lesion, decalcified sections were prepared, and examined by histological and immunohistological analysis. RESULTS: The surgical wound became completely covered with mucosal epithelia, and postoperative pain disappeared. No recurrence of ONJ was noted during a 6-month postoperative follow-up period. However, the patient died from metastatic disease. Although histopathological examination of the resected jaw bone revealed sequestrum, osseointegration of the implant was maintained. In the area around the lesion, there was no progression of bone necrosis, and reactive bone formation, fibrosis, and invasion of lymphoid cells into the marrow cavity were observed. CONCLUSION: There is no effective treatment for ONJ caused by BPs, and conservative therapy based on clinicians' experience is recommended. However, if chemotherapy is planned, or if bone necrosis around implants is thought to harbor infection, the option of jaw resection should be considered.

Dissecting the Akt/mammalian target of rapamycin signaling network: emerging results from the head and neck cancer tissue array initiative.

PURPOSE: As an approach to evaluate the expression pattern and status of activation of signaling pathways in clinical specimens from head and neck squamous cell carcinoma (HNSCC) patients, we established the Head and Neck Cancer Tissue Array Initiative, an international consortium aimed at developing a high-density HNSCC tissue microarray, with a high representation of oral squamous cell carcinoma. EXPERIMENTAL DESIGN: These tissue arrays were constructed by acquiring cylindrical biopsies from multiple individual tumor tissues and transferring them into tissue microarray blocks. From a total of 1,300 cases, 547 cores, including controls, were selected and used to build the array. RESULTS: Emerging information by the use of phosphospecific antibodies detecting the activated state of signaling molecules indicates that the Akt-mammalian target of rapamycin (mTOR) pathway is frequently activated in HNSCC, but independently from the activation of epidermal growth factor receptor or the detection of mutant p53. Indeed, we identified a large group of tissue samples displaying active Akt and mTOR in the absence of epidermal growth factor receptor activation. Furthermore, we have also identified a small subgroup of patients in which the mTOR pathway is activated but not Akt, suggesting the existence of an Akt-independent signaling route stimulating mTOR. CONCLUSIONS: These findings provide important information about the nature of the dysregulated signaling networks in HNSCC and may also provide the rationale for the future development of novel mechanism-based therapies for HNSCC patients.

Enhanced susceptibility to apoptosis of oral squamous cell carcinoma cells subjected to combined treatment with anticancer drugs and phosphatidylinositol 3-kinase inhibitors.

The purpose of this study was to determine whether phosphatidylinositol 3-kinase (PI 3-K) inhibitors could modulate the apoptotic activity of the anticancer drugs cisplatin, 5-fluorouracil or docetaxel in an oral squamous cell carcinoma (OSCC) cell line, HSC-2. In preliminary experiments, cisplatin, 5-fluorouracil and docetaxel inhibited the proliferation of OSCC cells in a dose-dependent manner. We found that two PI 3-K inhibitors, wortmannin and LY294002, markedly suppressed the phosphorylation of Akt in OSCC cells. Treatment of OSCC cells with PI 3-K inhibitors significantly enhanced cisplatin-, 5-fluorouracil- or docetaxel-induced apoptosis. Caspase-3 and -9 inhibitors, but not a caspase-8 inhibitor, reduced anticancer drug-mediated apoptosis in PI 3-K inhibitor-treated OSCC cells, suggesting that the apoptotic pathway induced by the combination of anticancer drug therapy and PI 3-K inhibition may be functionally related to the intrinsic apoptotic pathway in OSCC cells. Expression of Bcl-2, cellular inhibitor of apoptosis protein-1 (cIAP-1), and X-linked IAP was down-regulated, and expression of Bax was up-regulated by PI 3-K inhibitors, while that of Bcl-xL, Bak and cIAP-2 was not attenuated. We also found that Bad phosphorylation was down-regulated by PI 3-K inhibitors. These results suggested that inhibition of PI 3-K enhances the susceptibility of OSCC cells to anticancer drug-mediated apoptosis through regulation of expression and post-translational modification of both pro- and anti-apoptotic proteins. These findings could potentially lead to new strategies for improving the efficacy of anticancer drugs in OSCC cells.

Enhanced susceptibility to tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in oral squamous cell carcinoma cells treated with phosphatidylinositol 3-kinase inhibitors.

In general, oral squamous cell carcinoma (OSCC) cells are relatively resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis during culture in vitro. Here, we studied the role of phosphatidylinositol 3-kinase (PI 3-K)/Akt in survival and apoptosis of these cells. The PI 3-K inhibitors wortmannin and LY294002 markedly suppressed phosphorylation of Akt and accelerated TRAIL-mediated apoptosis in OSCC cells. Addition of TRAIL to PI 3-K inhibitor-treated cells resulted in caspase-8 activation and loss of mitochondrial membrane potential. Furthermore, inhibitors of caspase-3, -8 and -9 reduced the accelerative effect of PI 3-K inhibitors on TRAIL-mediated apoptosis. These results suggest that the pro-apoptotic effect of PI 3-K inhibitors on TRAIL-mediated apoptosis may contribute to both the extrinsic and intrinsic pathways. Although PI 3-K inhibitors did not affect expression of the TRAIL receptors DR4 and DR5, we observed a marked reduction in expression of cellular FLICE-inhibitory protein (c-FLIP), Bcl-2, cellular inhibitor of apoptosis protein-1 (cIAP-1) and X-linked IAP (XIAP), whereas Bax was up-regulated and no significant difference was observed in expression of Bcl-xL, Bak or cIAP-2. Therefore, the PI 3-K/Akt signaling pathway provides partial regulation of TRAIL-mediated apoptosis in OSCC cells via modulation of c-FLIP, Bcl-2, Bax, cIAP-1 and XIAP expression. These results suggest that PI 3-K inhibitors may represent a novel strategy for overcoming resistance to TRAIL-mediated apoptosis in OSCC cells.

Effect of combining epidermal growth factor receptor inhibitors and cisplatin on proliferation and apoptosis of oral squamous cell carcinoma cells.

Epidermal growth factor (EGF) is known to be involved in the proliferation and metastasis of squamous cell carcinoma (SCC), suggesting that the EGF receptor (EGFR) must also contribute to SCC development. In combination with conventional anti-cancer drugs, agents that block EGFR may represent an efficient means of inhibiting proliferation and inducing apoptosis in SCC cells. We investigated the effects of combining an anti-EGFR monoclonal antibody (C225) or an EGFR-selective tyrosine kinase inhibitor (AG1478) with the conventional anti-cancer drug cisplatin on the oral SCC (OSCC) cell lines NA and Ca9-22. We detected constitutive expression of EGFR on the cell membranes of both cell lines. OSCC cell proliferation was inhibited by C225, AG1478 and cisplatin in a dose-dependent manner. The combination of C225 or AG1478 with cisplatin at concentrations

Tumor-specific cytotoxic activity and type of cell death induced by 4-trifluoromethylimidazoles in human oral squamous cell carcinoma cell lines.

Fourteen 4-trifluoromethylimidazole derivatives were investigated for their cytotoxicity against three human normal cells (gingival fibroblast HGF, pulp cell HPC and periodontal ligament fibroblast HPLF) and four human tumor cell lines (oral squamous cell carcinoma HSC-2, HSC-3, HSC-4 and promyelocytic leukemia HL-60). Among these compounds, 4-trifluoromethyl-1,2-diphenylimidazole (IM5), 1-benzyl-4-trifluoromethyl-2-phenylimidazole (IM7) and 5-[1-ethoxy-2,2,2-trifluoro-1-(trifluoromethyl) ethyl]-1-methyl-2-phenyl-1H-imidazole (IM12) showed much higher cytotoxicity and tumor-specificity than the other compounds. IM5, the most potent compound, induced different types of cell death depending on the target cells. IM5 induced DNA fragmentation of oligonucleosomal units (a biochemical hallmark of apoptosis) in the HL-60 cells, but not in such a clear-cut laddering pattern in the HSC-2 cells. On the other hand, IM5 produced secondary lysosomes digesting broken organelles, without induction of internucleosomal DNA fragmentation and disappearance of cell surface microvilli in the HSC-4 cells, even though the HSC-2 and HSC-4 cells showed comparable sensitivity to IM5. These data suggest that the type of cell death is determined by the type of target cells, but not by the drug-sensitivity of the cells.

CXCR4 expression is associated with lymph-node metastasis of oral squamous cell carcinoma.

The support mechanisms that are involved in lymph-node metastasis of oral squamous cell carcinoma (OSCC) remain largely unknown. Recent studies have demonstrated that tumor cells express chemokine receptors and use chemokines to metastasize to the target organ in many malignancies in humans. In this study, we examined the expression and function of chemokines and their receptors in OSCC. The expression of chemokine receptors was assessed in eight OSCC cell lines. CXCR3 mRNA and protein were expressed in all the OSCC cell lines examined, while CXCR4 mRNA and protein were expressed only in HSC2, HSC3, and Ca9-22 cells. Treatment with the ligand for CXCR4, stromal cell-derived factor-1 (SDF-1), enhanced the motility and invasiveness of OSCC cells expressing CXCR4. However, the CXCR3 ligand, Mig, did not affect the migration or invasiveness of CXCR3-positive cells. We also evaluated the clinical significance of CXCR4 expression immunohistochemically. CXCR4 expression was detected in 27 (30%) of the 90 OSCC tissues tested, and was localized in the membrane and cytoplasm of cancer cells. There was a highly significant correlation between CXCR4 expression and lymph-node metastasis (P=0.0035). Collectively, these findings suggest that CXCR4 might be involved in the lymph-node metastasis of OSCC.

Hypoxia enhances c-Met/HGF receptor expression and signaling by activating HIF-1alpha in human salivary gland cancer cells.

Hypoxia increases the invasive and metastatic potential of tumor cells. Increased expression of c-Met/hepatocyte growth factor (HGF)-receptor protein in response to hypoxia in thyroid papillary carcinomas is hypoxia-inducible factor-1 (HIF-1) dependent. Both HGF and c-Met are expressed in human salivary gland cancers. In the current study, we tested whether c-Met expression was regulated by hypoxia and HIF-1alpha using two human salivary gland cancer cell lines: GFP-ACC2 and GFP-ACCM. Hypoxia enhanced the expression of HIF-1alpha in both cell lines, whereas c-Met was markedly induced only in the GFP-ACCM cells, which have metastatic potential. In the latter, hypoxia also promoted HGF-induced invasiveness. Synthetic small-interfering RNA specific for HIF-1alpha inhibited HIF-1alpha expression in the GFP-ACCM cells, and also suppressed the increase in c-Met expression and HGF-induced invasiveness under hypoxic conditions. These results suggest that hypoxia activates the HGF/c-Met system via HIF-1alpha in human salivary gland cancers and might be involved in their metastasis.

Anti-tumor effect of radiation response by combined treatment with angiogenesis inhibitor, TNP-470, in oral squamous cell carcinoma.

Blocking angiogenesis may enhance conventional anticancer treatments such as radiation therapy. In this study, we examined the effects of the angiogenesis inhibitor TNP-470 on human OSCC cell lines HSC2 and KB, with combining radiation therapy in the nude mouse. We evaluated cell-induced neovascularization with dorsal air sac assay, and selected two cells (HSC2: low, KB: high) with different level of cell-induced angiogenesis. The angiogenesis inhibitor TNP-470 was given 30 mg/kg s.c. daily on day 1-5, and irradiation, 8 Gy x 1, was administered on day 1 each week for 3 weeks. Significant inhibition of tumor growth relative to untreated controls was achieved in KB cells showing high induced angiogenesis with both TNP-470 (P < 0.01) and radiation (P < 0.01) and combining TNP-470 and radiation (P < 0.01). We saw little effect of TNP-470 either alone or in addition to the effect of radiation on the HSC2 cells showing low induced angiogenesis. These results suggested that TNP-470 significantly enhanced the effect of radiation on the cells with high neovascularization. These findings indicated that individual evaluation of each tumor neovascularization potential will be important before deciding the anti-angiogenesis treatment.

Effects of apatite foam combined with platelet-rich plasma on regeneration of bone defects.

The objective of this study was to investigate the regenerative effects of apatite foam (AF) combined with platelet-rich plasma (PRP) on bone defects. Critical-sized defects in the tibia of rats were filled with randomly distributed combinations of AF with and without PRP. The animals were killed after three, six, and 12 weeks, and their tissue responses were histologically examined. At three weeks, we found no significant differences in bone regeneration against control group (21.9 +/- 3.1%) when PRP (20.3 +/- 4.2%) and AF (21.6 +/- 2.9%) were used independently of each other. In contrast, significantly (p<0.01) larger amount of bone (32.3 +/- 6.5%) was formed when the defect was filled with PRP-incorporated AF. At six weeks, both PRP (38.1 +/- 3.2%) and AF (39.6 +/- 7.8%) showed significantly (p<0.05) higher rates of bone regeneration than the control, even though they were used independently. Moreover, the amount of regenerated bone significantly (p<0.01) increased in the defect filled with PRP-incorporated AF (76.1 +/- 8.2%). We concluded, therefore, that the combination of PRP and AF may be useful for the regeneration of defected bone.