佐瀬 美和子

The small intestine has a robust regenerative capacity, and various cell types serve as "cells-of-origin" in the epithelial regeneration process after injury. However, how much each population contributes to regeneration remains unclear. Using lineage tracing, we found that Lgr5-expressing cell derivatives contained radioresistant intestinal stem cells (ISCs) crucial for epithelial regeneration in the damaged intestine after irradiation. Single-cell qRT-PCR analysis showed that surviving Lgr5-expressing cell derivatives in the damaged intestine are remarkably heterogeneous, and that the expression levels of a YAP-target gene Sca1 were inversely correlated with their "stemness", suggesting that the YAP/Wnt signal balance in surviving crypt epithelial cells determines the cellular contribution to epithelial regeneration. Single-cell RNA sequencing of Sca1-Lgr5-derivatives revealed that expression of a tetraspanin family member CD81 correlated well with the expression of ISC- and proliferation-related genes. Consistent with these findings, organoid-forming ability was confined to the CD81hiSca1- fraction within the damaged crypt epithelial cells. Characterization of radioresistant epithelial stem cell heterogeneity in the damaged intestine may contribute to therapeutic strategies for gastrointestinal diseases.

Ghost cell odontogenic carcinoma (GCOC) is a rare malignant odontogenic tumor with aggressive growth characteristics. We report a case of GCOC of the maxilla in a 65-year-old Japanese man who was referred to our hospital with painful swelling of the left maxilla. Computed tomography showed a bone defect in the left upper jaw and the border with the surrounding tissue was indistinct in one area. Tumor resection was performed under general anesthesia, and the histopathological diagnosis was dentinogenic ghost cell tumor (DGCT). Ten months postoperatively, the tumor recurred in the same area, and partial resection of the maxilla was performed. Twelve months after reoperation, the tumor recurred a second time. The histopathological diagnosis this time was GCOC, as a secondary malignant manifestation of the benign DGCT.

We report a very rare case of systemic amyloidosis occurring in bilateral mandibular condyles and showing condylar bone destruction and lesions in the buccal mucosa bilaterally. The patient was a 61-year-old man complaining of malocclusion in which the lower teeth extended abnormally over the upper teeth. He first noticed this about 1 year earlier. Medical history included renal cancer, rheumatic myalgia in multiple joints, osteoporosis, hypothyroidism, chronic hepatitis, malignant lymphoma and hemodialysis for renal failure. Panoramic radiography and computed tomography showed bone destruction in bilateral mandibular condyles and a soft tissue mass lesion around the condyle. Slightly raised mass lesions with areas of whitish and purplish coloration were also observed on the buccal mucosa bilaterally. Histopathological examination revealed amyloid deposition in these lesions, and AA and/or Aβ2M amyloidosis was diagnosed. However, we were informed that the patient died within 3 months from when he had a last check-up at our clinic due to systemic problems.

Small cell carcinoma in the oral and maxillofacial region is an extremely rare, high-grade malignancy. We report a case of small cell carcinoma in the palatal mucosa. An 80-year-old man was referred to our clinic with swelling in the right maxilla. An 80-mm lymph node was seen in the right neck. The clinical diagnosis was malignant tumor of the palatal mucosa and biopsy was performed. The histopathological diagnosis was small cell carcinoma. Systemic examination diagnosed cervical lymph node metastasis, liver metastasis and multiple bone metastases. Considering the clinical stage and performance status, best supportive care was selected. The patient died of multiple-organ failure 3 months after the first visit.

A rare case of acute myelocytic leukemia that relapsed in association with the formation of a gingival tumor is presented. The patient was a 45-year-old man who had been referred to our department for oral examination before starting chemotherapy. No gingival swelling was found on the initial visit. However, about 4 months after complete remission was achieved, he noticed a gingival tumor arising in the left side of the mandible. The tumor was 47 × 32 mm in size and elastic hard, with a relatively well defined border. Pathologically, the lesion was diagnosed as leukemic cell infiltration, despite the hematologic remission. The patient died of respiratory failure about 3 months after presentation, with no response to chemotherapy.

We report a case of oral ulceration during the treatment of type-2 diabetes mellitus with a dipeptidyl peptidase (DPP)-4 inhibitor, sitagliptin. The patient was a 77-year-old woman with oral ulceration of the left lower labial mucosa. The ulcer showed a flat, clean surface with no bleeding. Ulcer margins were slightly raised and showed no induration. Topical steroid proved ineffective and the ulcer was surgically resected, but soon recurred. After cessation of sitagliptin, the lesion epithelialized within 3 weeks. This report is the first report of oral ulceration induced by DPP-4 inhibitor. © 2012 Asian AOMS, ASOMP, JSOP, JSOMS, JSOM, and JAMI.

For objective neurophysiological evaluation of the function of the trigeminal system, magnetoencephalography-based TSEF (trigeminal somatosensory-evoked field) assessment would be valuable in providing spatial and temporal profiles of cortical responses. However, this necessitates knowledge of how TSEF varies with trigeminal nerve dysfunctions. We introduced a conduction block of the trigeminal nerve using local anesthesia (lidocaine) to temporally mimic nerve dysfunctions, and monitored TSEF changes. Following an electrical stimulation of the lower lip, a magnetic response with peak latency of approximately 20 ms was identified in all participants. Dipole for the peak was estimated on the post-central gyrus in the participant's own magnetic resonance image. After normalization to Montreal Neurological Institute (MNI) space and inter-participant data integration, the summary equivalent current dipole localization among participants remained in the post-central gyrus, suggesting validity of the use of MNI space. Partial anesthesia of the lower lip led to a loss of the waveform characteristics of TSEF for electrical stimulation to the trigeminal nerve. We verified that the 20-ms latency cortical response of TSEF components localized at the primary sensory cortex can serve as a robust neurofunctional marker of experimental trigeminal nerve dysfunction.

2004年4月～2009年7月に当科受診し口腔癌と診断された患者のうち紹介医のあった29例について検討した。年齢は50歳代が5例、60歳代6例、70歳代8例、80歳代8例、90歳代1例で、平均年齢は72.2歳であった。性別は男性19例、女性10例で、男女比1.9:1であった。発生部位は、舌12例(41%)、上顎歯肉8例(28%)、下顎歯肉6例(21%)、口唇2例(7%)、頬粘膜1例(3%)の順に多かった。紹介医の内訳は、歯科医16例(55%)、内科医12例(41%)、皮膚科医1例(3%)であった。受診経路を発生部位別にみると、上顎歯肉は8例中7例が歯科医院を受診し、下顎歯肉は6例中5例が歯科医院を受診、舌は12例中10例が内科を受診していた。紹介病名は、悪性腫瘍10例(34%)、難治性潰瘍5例(17%)、腫瘍4例(14%)、軟組織腫脹3例(10%)、白板症3例(10%)、智歯周囲炎1例(3%)、歯根嚢胞1例(3%)、その他2例であった。初診時の病期分類はstage Iが5例(17%)、IIが15例(52%)、IIIが2例(7%)、IVが7例(24%)であり、3/4の症例が進行癌になる前に当科を受診していた。

口腔内装置にて治療した中等度から高度の睡眠時無呼吸症候群(SAS)14例(平均52.3歳)を対象とし、その有効性を検討した。簡易睡眠検査による口腔内装置装着前のAHI(無呼吸・低呼吸指数)は平均54.3、睡眠時の経皮的動脈酸素飽和度(SPO2)は平均73.8%であり、全例が日中の眠気を訴えたが、口腔内装置装着後は全例でAHIが改善し、12例でSPO2の改善を認めたほか、自覚症状の改善は7例で認められた。また、N-CPAP療法から口腔内装置への変更は5例で可能であり、中等度症例の改善率は50%、重度症例では30%であった。今回、中等度あるいは高度のSASでも口腔内装置が有効な症例が存在し、特に中等度症例に有効症例を多く認めた。中等度の症例で口腔内装置を希望した症例は適応ありと考えられた。