Hiroichi Kobayashi

Ectopic osteogenesis with biphasic ceramics of hydroxyapatite and tricalcium phosphate in rabbits

Porous calcium phosphate ceramics consisting of hydroxyapatite (HA) and tricalcium phosphate (TCP) with different HA to TCP ratio were implanted intramuscularly in rabbits for six months in order to carry out a comparative study on osteogenic activity of the ceramics. Bone formation was detected only in HT73 (HA to TCP ratio, 7-3) specimens. Other implants, HT28 (2-8) and HT010 (0-10), could not induce bone. After a six-month period of implantation, HT28 and HT010 implants showed obvious degradation of the implants changing their shape and size macro and microscopically. Microscopically, they showed aggregates of fine particles and appearance of multinucleated cells. However, HT73 implants was less degraded and could maintain their original structure macro and microscopically. This study showed that HT73 ceramics can induce bone in rabbit muscle tissue and it is considered that maintenance of porous structure, that is, degradation rate of the materials may be one of the affecting factors in ceramic-induced osteogenesis.

Clinical Significance of Cellular Distribution of Moesin in Patients with Oral Squamous Cell Carcinoma

Purpose: Moesin is a linking protein of the submembraneous cytoskeleton and plays a key role in the control of cell morphology, adhesion, and motility. The aim of the present study was to elucidate the clinical significance of expression patterns of moesin in patients with oral squamous cell carcinoma (OSCC). Experimental Design: Immunohistochemistry for moesin monoclonal antibody was performed on 103 paraffin-embedded specimens from patients with primary OSCC, including 30 patients with locoregional lymph node metastasis, and in the sections from nude mice transplanted with two cell lines derived from a single human tongue cancer (SQUU-A and SQUU-B). Results: Expression patterns of moesin in OSCCs were divided into three groups: membranous pattern; mixed pattern; and cytoplasmic pattern. These expression patterns correlated with tumor size, lymph node metastasis, mode of invasion, differentiation, and lymphocytic infiltration. In about two-thirds of the patients with metastatic lymph node, homogeneous cytoplasmic expression was detected in the metastatic lymph nodes. In addition, SQUU-B with high metastatic potential showed more reduced levels of membrane-bound moesin than SQUU-A with low metastatic potential. A multivariate analysis demonstrated that expression patterns of moesin can be an independent prognostic factor. Conclusions: Our results suggest that moesin expression contributed to discriminating between patients with the potentiality for locoregional lymph node metastasis and those with a better prognosis and might improve the definition of suitable therapy for each.

Impact of different surgical margin conditions on local recurrence of oral squamous cell carcinoma

The purpose of this study was to analyze the impact of different surgical margin conditions on local recurrence of oral squamous cell carcinoma (SCC) in 148 consecutive patients who underwent planned radical resection of oral SCC. The patients were classified into four categories according to the status of the surgical margin: clear (no SCC within 5mm, n=103), close (SCC within 5mm, n=21), dysplasia (dysplastic epithelium at margin, n=13), and involved (SCC at margin, n=11). Coxs proportional hazard model showed that the status of the surgical margin had a significant impact on local recurrence (p<0.003); hazard ratio was 3.79 (95%CI: 1.17-12.28) with a close and 7.89 (2.38-26.17) with an involved margin. The presence of mucosal dysplasia at the surgical margin was also a significant predictor of local recurrence (hazard ratio: 5.29, 95%CI: 1.31-21.29). Local recurrence was observed only with severe dysplasia, while no recurrence with mild and moderate dysplasia. In the patients with a clear and closed surgical margin, local recurrence was related with T4 tumor and an advanced mode of tumor invasion. The results of this study suggested that the presence of tumor cells at or close to the surgical margin increased the risk of local recurrence. The presence of dysplastic epithelium (especially severe dysplasia) at the mucosal surgical margin has a significant impact on local control. It was also suggested that not simply the width of the free margin but also clinical and histological risk factors should be included in deciding the necessity for adjuvant radiotherapy.

Osteoinduction with HA/TCP Ceramics of Different Composition and Porous Structure in Rabbits

Abstract To determine the effect of material factors on Ca-P biomaterial-induced osteogenesis, six kinds of biphasic calcium phosphate (BCP) ceramics with different HA to TCP ratio (HA/TCP 2-8, 7-3) and different porous structure (micro-, macro- and micro/macro- porous structures) were implanted intramuscularly in rabbits. Different tissue response was detected histologically and microradiographically after the ceramic samples were implanted in the dorsal muscles of rabbits for 3 and 6 months. Obvious bone formation was found in two kinds of ceramics with the same micro/macro- porous structure at both 3 and 6 months. In contrast, no bone formation or host tissue invasion was detected in two other kinds of ceramics with only microporous structure, even after 6 months implantation. Some bone formation was found occasionally in two kinds of ceramics with only macro-porous structure at 6 months. Bone tissue was usually formed in direct contact with the pore surface and was only located in non-dissolved porous regions. Osteocyte lacunae were seen and no pathological calcifications were observed. These results indicate that micro- and macro-porous structure play an important role in the osteoinduction with Ca-P ceramics. Furthermore, the results showed that the osteoinductive capacity of BCP ceramics was influenced by the different dissolution rate through changing HA/TCP ratio.

Cultured epithelial grafting using human amniotic membrane: the potential for using human amniotic epithelial cells as a cultured oral epithelium sheet.

OBJECTIVE Human amniotic cells are a valuable source of functional cells that can be used in various fields, including regenerative medicine and tissue engineering. The aim of this study was to investigate the utility of human amniotic epithelial (hAE) cells as a new cell source for culturing stratified epithelium sheets for intraoral grafting. METHODS Enzymatically isolated hAE cells were submerged in a serum-free, low-calcium-supplemented MCDB 153 medium without a feeder layer. The hAE cells were seeded onto a Millicell cell culture plate insert and cultured while submerged in a high-calcium medium for 4 days. Then, they were cultured at an air-liquid interface for 3 weeks. Cultures of hAE cells proliferated at the air-liquid interface. RESULTS After 3 weeks, the hAE cells cultivated using the air-liquid interface method lead to almost 10 continuous layers of stratified epithelium without parakeratinization or keratinization. It confirmed immunohistochemically that the presence of CK10/13 and Ki-67 positive cells were spread throughout almost all the epithelial layer, and that CK19 positive cells were expressed throughout the entire epithelial layer in the cultured hAE cell sheets. Cultured hAE cells sheets showed a staining pattern similar to that of uncultured oral mucosa: ZO-1 and occludin were located in the intercellular junctions throughout all the epithelial layers. It was suggested that the hAE sheets consisted of highly-active proliferating cells and undifferentiated cells, and had a barrier function. CONCLUSIONS These results suggested that hAE cells may be a promising cell source for the development of stratified epithelium allograft sheets using a human cell strain.

Accuracy of intraoperative tissue staining in delineating deep surgical margins in oral carcinoma surgery

The purpose of this study was to assess the accuracy of this tissue staining assessment of surgical specimens in delineating deep surgical margins in oral cancer surgery. Fifteen patients who underwent surgery for oral carcinoma were included in the study. Once the tumor was resected, a vertical section of the surgical specimen was taken from the central part of the tumor. The section was consecutively stained with 0.4% indigo carmine and 0.5% Congo red, and deep surgical margins were assessed using a digital microscope with a magnification power of 25-175x. The results of tissue staining analysis were compared with the corresponding results of conventional histopathological analysis with HE staining, which is considered the gold standard. The extent of carcinoma invasion could be visualized after the application of tissue staining solutions. Tissue staining analysis was accurate in 12 of the 15 patients (80%) in evaluating the closest deep surgical margin. There was no significant difference in the tumor-margin distance between tissue staining and histopathological assessment in these 12 patients (Wilcoxon signed-ranks test, P>0.63). The results of this study showed that intraoperative tissue staining of surgical specimens permitted visual inspection and assessment of tumor spread to surgical margin, although the method has some limitations. The method had a possible ability in controlling the deep surgical margin.

Clinical significance of apoptosis-associated speck-like protein containing a caspase recruitment domain in oral squamous cell carcinoma

OBJECTIVES To assess apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) expression in oral squamous cell carcinoma (OSCC) and analyze its clinical and pathological significance. STUDY DESIGN ASC expression was studied using immunohistochemistry in 119 OSCCs patients. The relationships between ASC expression and clinical and pathological parameters were statistically analyzed. In addition, the relationships between ASC expression and cell differentiation [IVL (involcrin) expression] and apoptosis (TUNEL [TdT-mediated dUTP nick end labeling] positive cell number) were investigated. RESULTS ASC expression showed significant correlations with parameters including clinical tumor stage, mode of invasion, and histological differentiation, and had a significant impact on survival of OSCC. The distribution of ASC correlated well with that of IVL. ASC expression was significantly correlated with the TUNEL-positive cell number. CONCLUSIONS Lower ASC expression correlates with clinical and pathological malignancy and, consequently, poor prognosis of OSCC. ASC has a close association with cell differentiation and apoptosis.

Intraoperative Tissue Staining of Invaded Oral Carcinoma

The purpose of this study was to assess the ability of intraoperative tissue staining with consecutive application of 0.4% indigo carmine and 0.5% Congo red to demonstrate the extent and border of oral carcinoma invasion. Seventeen patients were included in the study. Once the oral tumor was resected, a vertical section of surgical specimen was taken from the central part of the tumor. The extent and border of the invaded carcinoma were assessed on digital microscopic examination with tissue staining. The results of assessments were compared with corresponding results of conventional histopathological analysis with HE staining, which is considered the gold standard. Tissue staining produced a brown-black stain on normal muscle, connective, and salivary tissues but not tumor and epithelial tissues. It clearly demonstrated the extent and border of tumor invasion in 13 of 17 patients (76.5%); however, detection of remnant vital tumor cells in scar tissue after neoadjuvant chemotherapy, and distinction between the tumor and adipose tissue scattered in the muscle tissue was difficult. The results of this study showed that intraoperative tissue staining was a possible method in demonstrating the extent and border of carcinoma deeply invaded in the soft tissue and selecting the site for additional frozen section analysis, although the method needed some refinement.

Three Cases of Oral Cancer in a Patient with Dementia-The Problems in Patient Management During Hospitalization-

高齢化社会を迎え, 痴呆症を有し口腔癌を発症する高齢者も増加してきている。この様な患者の治療は大変困難である。最近われわれは, 痴呆を有する高齢者の口腔癌患者を3症例経験し, 様々な治療上の問題点が明らかとなった。痴呆症を有する患者との意思の疎通は困難であり, 疾患・診療に対する理解が得られないため, 入院管理が非常に困難である。合併症や痴呆に起因する様々な要因により, 治療法の選択に制約がある。またさらに家族の治療への積極的な協力が得にくく, 治療はより難しくなる。痴呆を有する患者の治療方針を決定する際には, 腫瘍の進展度全身状態, 合併症だけでなく, 年齢, 痴呆の重症度患者のQOL, 家族の意向等を考慮することが重要であると考えられた。

Survival Rates After Surgical or Non-surgical Treatment for Advanced Resectable Squamous Cell Carcinoma of the Oral Cavity and Oropharynx

Objective: To determine the difference in survival rates between surgical and non-surgical treatment for resectable squamous cell carcinoma of the oral cavity and oropharynx. Patients and Methods: A retrospective chart review of 53 patients in a single institution who preferred surgical treatment and 11 patients who preferred non-surgical treatment. Results: The overall survival probability rate of the surgically-treated patients was 90% at 1 year, 76% at 2 years, and 61% at 5 years, while that of the non-surgically—treated patients was 60%, 30%, and 15%, respectively. The difference in the cause-specific survival rate between the 2 groups was significant (logrank test, p < 0.05). There were significant differences in the distribution of patients age, T-stage, N-stage, and performance status. However, the Cox multivariate analysis revealed that the treatment was a significant independent predictor. Conclusions: The results suggest that when non-surgical treatment is given for resectable cancer, the probability of survival from the disease is 30% and death would occur within 2 years. The survival rate is half that of those who undergo radical surgery (67%).