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Abstract Introduction Glucose transporter 1 (GLUT1) deficiency is a rare cerebral metabolic disorder caused by the shortage of glucose supply to the brain. For this disease, ketogenic diet therapy is essential. In addition, perioperative management requires not only the continuation of ketogenic diet therapy but also the management of nausea/vomiting, diarrhea, seizures, and infection. However, there have been few reports regarding oral and maxillofacial surgery. Case presentation We describe a patient with GLUT1 deficiency who underwent orthognathic surgery. An 18-year-old man was referred to our hospital with the chief complaint of mandibular regression. Surgical tolerance was assessed by a fasting test and tooth extraction under general anesthesia, and orthognathic surgery was then performed. For orthognathic surgery, the mandibular dentition had scissor-like occlusion, and it was difficult to arrange the mandible. Therefore, we decided to perform maxillary osteotomy first. After the mandibular dentition was arranged by maxillary osteotomy, sagittal split ramus osteotomy (SSRO) was performed. Intermaxillary fixation (IMF) was necessary for SSRO, and caution was needed to prevent suffocation. The orthognathic surgery was successful, although complications, such as vomiting, diarrhea, and seizures, developed. Conclusion Surgical orthodontic treatment in GLUT1 deficiency can be performed relatively safely by maintaining the diet, taking measures against epilepsy and vomiting, and using antimicrobial agents in close collaboration with pediatricians, anesthesiologists, pharmacists, and nutritionists.

Although vascular invasion (VI) is recognized as an important predictor of lymph node metastasis and a significant prognostic factor in head and neck squamous cell carcinoma (HNSCC), there is currently no common definition for the pathological evaluation of VI status. We reviewed the medical records of 63 consecutive resected primary oral tongue SCCs (OTSCCs) without preoperative treatment between June 1999 and April 2008, and evaluated VI status by investigating lymphatic vessel invasion (LVI) and blood vessel invasion (BVI) by using immunohistochemistry (IHC) with monoclonal antibody D2-40 (D2-40) and Elastica van Gieson (EVG) staining, respectively. Subsequently, we analyzed their correlations with cervical lymph node metastasis and prognosis. LVI was found in 16 of the 63 tumors (25.4%) and BVI was in 32 tumors (50.8%). Univariate analysis revealed that the presence of LVI is statistically correlated with lymph node metastasis. Moreover, multivariate logistic regression analysis revealed that LVI is an independent risk factor of nodal metastasis (odds ratio=4.262, 95% confidence interval=1.262-14.397, p=0.020). In contrast, Kaplan-Meier survival analysis revealed that patients with BVI had a significantly shorter disease-free survival (DFS) and overall survival (OS) rates than those without BVI (68.6% versus 90.3%, p=0.028 and 68.6% versus 93.5%, p=0.013, respectively). The present study clearly demonstrated that LVI at primary OTSCC had significant correlation with lymph node metastasis, and that BVI was significantly associated with recurrence and poor prognosis. Evaluation of VI status, as LVI and BVI status separately, using IHC with D2-40 and EVG staining may be useful in predicting lymph node metastasis and poor prognosis in OTSCCs. [ABSTRACT FROM AUTHOR]

Regardless of age and skill, many people in Japan today now enjoy dance classes. Since each dance event (ballet, modern dance, jazz dance, aerobic dance etc.) possesses characteristic movements, injuries suffered depend on the type of dance. The age and skill of dancers also relate to the type of injuries sustained. We epidemiologically investigated 2,118 dance injuries to clarify their entire characteristics at the Division of Orthopedic Sports Medicine, Kanto-Rosai Hospital. We also focused on the dependency of injuries on dance events, dancer's age and the transition in aspects of injuries over the past 22 years. As a result, injuries in the lower extremities (non-specific knee pain, ankle sprain, foot and toe pain and Achilles tendonitis) are most apparent in all dance items. Concerning specificities in dance events, shin splint and planter fasciitis occurred frequently in jazz and aerobic dances. Posterior impingement syndrome and symptomatic accessory navicular were apparent in ballet dancers. The effect of age on dance injuries also became apparent. Acute injuries and spondylolysis frequently occurred in young dancers. With the advance of age, age-related injuries (gastrocnemius muscle strain injuries etc.) became prominent. In the past 22 years, construction of the patients' age bracket has changed. The number of patients under 30 years old remains unchanged, but that of over 30 years old is increasing. The proportion of patients over 50 years old, too, is increasing in every item. The prevalence of knowledge of injury prevention and progress in medical treatment influences the incidence of injuries. Prescription considering the age and personal physical characteristics of dancers is necessary for the selection of suitable dance items, a medical check up regimen, conditioning system and a therapeutic approach. [ABSTRACT FROM AUTHOR]

Abstract Background Although chromosomal instability (CIN) has been detected in many kinds of human malignancies by means of various methods, there is no practical assessment for small clinical specimens. In this study, we evaluated CIN in fine-needle aspiration (FNA) biopsied oral squamous cell carcinomas (SCCs) using fluorescence in situ hybridization (FISH) analysis, and investigated its prognostic significance. Methods To evaluate CIN status of tumors, FISH with genomic probes for the centromeres of chromosomes 7, 9, and 11 was performed on specimens obtained by FNA from 77 patients with primary oral SCCs. Results High-grade CIN (CIN3) was observed in 11.7% (9/77) of patients with oral SCCs and was associated significantly with reduced disease-free survival (p = .008) and overall survival (p = .003). Multivariate Cox proportional hazards analysis showed that CIN status was significantly correlated with disease-free survival (p = .035) and overall survival (p = .041). Conclusion Analysis of CIN status using FISH on FNA biopsy specimens may be useful in predicting of recurrence and poor prognosis in patients with oral SCCs.

Secretory carcinoma (SC) is an uncommon salivary gland tumor that has been recently conceptualized. The present report describes a case of SC that was diagnosed as a mucocele on preoperative examination. A 46-year-old man presented to the Department of Oral and Maxillofacial Surgery at Saiseikai Senri Hospital (Suita-shi, Japan) with a main complaint of swelling of the right buccal mucosa. A mobile, elastic, hard mass was found beneath the right normal-appearing buccal mucosa. T2-weighted magnetic resonance imaging revealed a well-defined, internally homogeneous high-signal area with a maximum diameter of 18 mm. Based on the clinical diagnosis of mucocele, the buccal lesion was excised. Histopathological, immunohistochemical and fluorescence in situ hybridization analyses revealed the cystic lesion to be a macrocystic SC of a minor salivary gland. SC may have a mucocele-like appearance on magnetic resonance imaging. Even if a non-neoplastic lesion is suspected, the possibility of a malignant lesion such as SC must be considered for salivary gland disease., Competing Interests: The authors declare that they have no competing interests., (Copyright: © 2024 Chida et al.)

The process of cervical lymph node metastasis is dependent on the phenotype of the tumor cells and their interaction with the host microenvironment and immune system; conventional research methods that focus exclusively on tumor cells are limited in their ability to elucidate the metastatic mechanism. In cancer tissues, a specialized environment called the tumor microenvironment (TME) is established around tumor cells, and inflammation in the TME has been reported to be closely associated with the development and progression of many types of cancer and with the response to anticancer therapy. In this study, to elucidate the mechanism of metastasis establishment, including the TME, in the cervical lymph node metastasis of oral cancer, we established a mouse-derived oral squamous cell carcinoma cervical lymph node highly metastatic cell line and generated a syngeneic orthotopic transplantation mouse model. In the established highly metastatic cells, epithelial-mesenchymal transition (EMT) induction was enhanced compared to that in parental cells. In the syngeneic mouse model, lymph node metastasis was observed more frequently in tumors of highly metastatic cells than in parental cells, and Cyclooxygenase-2 (COX-2) expression and lymphatic vessels in primary tumor tissues were increased, suggesting that this model is highly useful. Moreover, in the established highly metastatic cells, EMT induction was enhanced compared to that in the parent cell line, and CCL5 and IL-6 secreted during inflammation further enhanced EMT induction in cancer cells. This suggests the possibility of a synergistic effect between EMT induction and inflammation. This model, which allows for the use of two types of cells with different metastatic and tumor growth potentials, is very useful for oral cancer research involving the interaction between cancer cells and the TME in tumor tissues and for further searching for new therapeutic agents., (© 2024. The Author(s).)

The tumor microenvironment (TME) concept has been proposed and is currently being actively studied. The development of extracellular matrix (ECM) in the TME is known as desmoplasia and is observed in many solid tumors. It has also been strongly associated with poor prognosis and resistance to drug therapy. Recently, cellular senescence has gained attention as an effect of drug therapy on cancer cells. Cellular senescence is a phenomenon wherein proliferating cells become resistant to growth-promoting stimuli, secrete the SASP (senescence-associated phenotypic) factors, and stably arrest the cell cycle. These proteins are rich in pro-inflammatory factors, such as interleukin (IL)-6, IL-8, C-X-C motif chemokine ligand 1, C-C motif chemokine ligand (CCL)2, CCL5, and matrix metalloproteinase 3. This study aimed to investigate the desmoplasia-like changes in the TME before and after cancer drug therapy in oral squamous cell carcinomas, evaluate the effect of anticancer drugs on the TME, and the potential involvement of cancer cell senescence. Using a syngeneic oral cancer transplant mouse model, we confirmed that cis-diamminedichloroplatinum (II) (CDDP) administration caused desmoplasia-like changes in cancer tissues. Furthermore, CDDP treatment-induced senescence in tumor-bearing mouse tumor tissues and cultured cancer cells. These results suggest CDDP administration-induced desmoplasia-like structural changes in the TME are related to cellular senescence. Our findings suggest that the administration of anticancer drugs alters the TME of oral cancer cells. Additionally, oral cancer cells undergo senescence, which may influence the TME through the production of SASP factors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background/purpose: For unresectable recurrent/metastatic head and neck cancer, pembrolizumab alone or pembrolizumab combined with cisplatin and 5-fluorouracil is the first-line therapy, depending on the PD-L1 combined positive score (CPS). However, this is based on clinical studies of head and neck cancer, and few similar studies have been conducted on oral cancer alone. This study aimed to investigate the current status of pharmacotherapy for unresectable, recurrent, or metastatic oral cancer., Materials and Methods: Patients with unresectable or recurrent/metastatic oral cancer who received cetuximab, nivolumab, or pembrolizumab as first-line treatment were reviewed. Overall survival (OS), progression-free survival (PFS), PFS 2 (PFS2), overall response rate (ORR), disease control rate (DCR), and immune-related adverse events were obtained from medical records., Results: A total of 155 patients were enrolled from six hospitals. The ORR in the nivolumab, pembrolizumab, and cetuximab groups was 17.2 %, 4.2 %, and 21.6 %, respectively, and the DCR was 37.9 %, 41.7 %, and 58.8 %, respectively. Median OS in nivolumab, pembrolizumab, and cetuximab groups was 10.3, 9.5, and 11.1 months, respectively. No significant differences were observed in survival among the three groups. The small number of cases and the retrospective nature of the study precluded the determination of the more effective first-line treatment among the three drugs., Conclusion: The current statuses of nivolumab, pembrolizumab, and cetuximab in unresectable recurrent metastatic oral cancer was reported., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2024 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

The transcription factor SRY-related HMG box 9 (Sox9) is essential for chondrogenesis. Mutations in and around SOX9 cause campomelic dysplasia (CD) characterized by skeletal malformations. Although the function of Sox9 in this context is well studied, the mechanisms that regulate Sox9 expression in chondrocytes remain to be elucidated. Here, we have used genome-wide profiling to identify 2 Sox9 enhancers located in a proximal breakpoint cluster responsible for CD. Enhancer activity of E308 (located 308 kb 5' upstream) and E160 (located 160 kb 5' upstream) correlated with Sox9 expression levels, and both enhancers showed a synergistic effect in vitro. While single deletions in mice had no apparent effect, simultaneous deletion of both E308 and E160 caused a dwarf phenotype, concomitant with a reduction of Sox9 expression in chondrocytes. Moreover, bone morphogenetic protein 2-dependent chondrocyte differentiation of limb bud mesenchymal cells was severely attenuated in E308/E160 deletion mice. Finally, we found that an open chromatin region upstream of the Sox9 gene was reorganized in the E308/E160 deletion mice to partially compensate for the loss of E308 and E160. In conclusion, our findings reveal a mechanism of Sox9 gene regulation in chondrocytes that might aid in our understanding of the pathophysiology of skeletal disorders.

Background: Cementoblastoma is a rare odontogenic tumor characterized by the formation of osteocementum-like tissue on a tooth root directly by neoplastic cementoblasts. Although it is categorized as benign, it has a high potential for growth with a certain degree of recurrence risk. However, there are only a few studies describing the features of recurrent cementoblastoma. The diagnosis of recurrent cementoblastoma is challenging not only due to its cytological atypia but also because of its large size and multicentric growth pattern. These characteristics suggest a potential for malignancy., Case Presentation: A 29-year-old woman was transferred to our university dental hospital complaining of swelling of the right mandible. She had a history of enucleation of cementoblastoma associated with the third molar of the right mandible. Five years after the initial treatment, imaging demonstrated well-circumscribed multicentric radiopaque lesions in the same area. Histologically, the lesion consisted of osteocementum-like tissue rimmed with polygonal or plump tumor cells. Several cells were large epithelioid cells with bizarre nucleoli, which may be reminiscent of malignant tumors. Otherwise, there were no apparent malignant findings, including proliferative activity or atypical mitotic figure. Besides, tumor cells were positive for c-FOS, a marker of osteoblastoma and cementoblastoma. Eventually, the patient was diagnosed with recurrent cementoblastoma., Conclusions: Pathological analyses of this case suggested that the recurrent event in the cementoblastoma altered its growth pattern and tumor cell shape. Moreover, in the case of enucleation surgery, long-term follow-up is important because there is some recurrent risk of cementoblastoma, although it is not high., (© 2024. The Author(s).)

This study aimed to identify risk factors associated with perforation of the undercut (U)-shaped lingual plate (LP) by the lower third molar (LM3) root using panoramic radiography (PAN). We retrospectively examined 468 impacted LM3s from 468 individuals, categorizing LM3-LP associations and LP morphology in the coronal section of cone-beam computed tomography as perforation or nonperforation and U-type or non-U-type, respectively. The outcome was the combination of perforation and U-type, and study variables included patient demographics (age and sex) and PAN-associated features (Winter's classification, Pell-Gregory classification, and two major Rood signs). Multivariate logistic regression methods were used for analysis. Perforated and U-type LPs were observed in 205 (43.8%) and 212 (45.3%) cases, respectively. The double-positive outcome was observed in 126 LM3s (26.9%). In the multivariate model, age ≥ 26 years [odds ratio (OR), 2.66; p = 0.002], men (OR, 2.01; p = 0.002), mesioangular (OR, 2.74; p = 0.038) and horizontal impaction (OR, 3.05; p = 0.019), and root darkening (OR, 1.73; p = 0.039) were independently associated with the risk. Class III impaction (OR, 0.35; p = 0.021) and interruption of the white line (OR, 0.55; p = 0.017) were negatively correlated with the risk. In conclusion, this study highlights the importance of identifying the higher probability of U-type LP perforation by the LM3 root in men aged over their midtwenties with Class I/II impaction and mesioangularly or horizontally impacted LM3s, along with root darkening and no interruption of the white line on PAN., (© 2023. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Periodontal disease is a risk factor for head and neck squamous cell carcinoma (HNSCC), and Porphyromonas gingivalis, a major periodontal pathogen, has been identified as a specific and potentially independent microbial factor that increases the risk of cancer mortality. Gene expression in HNSCC due to P. gingivalis infection and how changes in gene expression affect the prognosis of HNSCC patients are not clarified. When P. gingivalis was cultured with HNSCC cells, it efficiently adhered to these cells and enhanced their invasive ability. A transcriptome analysis of P. gingivalis -infected HNSCC cells showed that genes related to migration, including CCL20, CITED2, CTGF, C8orf44-SGK3, DUSP10, EGR3, FUZ, HBEGF, IL1B, IL24, JUN, PLAU, PTGS2, P2RY1, SEMA7A, SGK1 and SIX2, were highly up- or down-regulated. The expression of up-regulated genes was examined using the expression data of HNSCC patients obtained from The Cancer Genome Atlas (TCGA) database, and the expression of 5 genes, including PLAU, was found to be higher in cancer tissue than in solid normal tissue. An analysis of protein-protein interactions revealed that these 5 genes formed a dense network. A Cox regression analysis showed that high PLAU expression levels were associated with a poor prognosis in patients with TCGA-HNSCC. Furthermore, the prognostic impact correlated with tumour size and the presence or absence of lymph node metastasis. Collectively, these results suggest the potential of PLAU as a molecular prognostic marker in HNSCC patients. Further in vivo and in vitro studies are needed to verify the findings of this study., (© 2024 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Background: Squamous cell carcinoma (SCC) is the most common oral malignancy, and somatic mutations in some driver genes have been implicated in SCC development. Clear cell SCC (CCSCC) is a rare histological variant of SCC, and various clear cell neoplasms must be considered in the differential diagnosis of CCSCC in the oral cavity. Based on a limited number of CCSCC cases reported in the oral cavity, CCSCC is considered an aggressive variant of SCC with a poor prognosis; however, its genetic characteristics remain unknown., Methods: A maxillary gingival tumor in an 89-year-old female was described and investigated using immunohistochemical staining, special staining, fluorescence in situ hybridization, and next-generation sequencing (NGS) with a custom panel of driver genes, including those associated with SCC and clear cell neoplasm development., Results: Histopathological examination revealed a proliferation of atypical epithelial cells with abundant clear cytoplasm and enlarged and centrally placed round nuclei. The tumor was exophytic with deep, penetrating proliferation. The atypical clear cells were continuous with the conventional SCC cells. Immunohistochemical analysis showed that the clear cells were positive for CK AE1/AE3 and CK5/6 and nuclear-positive for p63. In contrast, the clear cells were negative for αSMA, S100, HMB45, Melan-A, CD10, and p16. p53 immunoreactivity exhibited a wild-type expression pattern. Additionally, the clear cells were positive for periodic acid-Schiff (PAS) and negative for diastase-PAS, mucicarmine, and Alcian blue. Based on these results, the diagnosis of CCSCC was confirmed. Molecular analysis of the clear cells identified PIK3CA p.E542K (c.1624G>A) and HRAS p.G12A (c.35 G>C) somatic mutations classified as oncogenic. No pathogenic variants were identified in TP53, EWSR1, AKT1, PTEN, BRAF, KRAS, NRAS, RASA1, or MAML2., Conclusions: We report a case of CCSCC of the oral cavity with PIK3CA and HRAS mutations. The identification of PIK3CA and/or HRAS mutations is rare in SCC; however, both mutations are important potential targets for antitumor therapy. A detailed analysis of gene mutations in CCSCC may lead to a better understanding of its biological behavior and an improved prognosis, as well as a differential diagnosis from other clear cell neoplasms., (© 2023. The Author(s).)

Streptococcus pyogenes harboring an FCT type 3 genomic region display pili composed of three types of pilins. In this study, the structure of the base pilin FctB from a serotype M3 strain (FctB3) was determined at 2.8 Å resolution. In accordance with the previously reported structure of FctB from a serotype T9 strain (FctB9), FctB3 was found to consist of an immunoglobulin-like domain and proline-rich tail region. Data obtained from structure comparison revealed main differences in the omega (Ω) loop structure and the proline-rich tail direction. In the Ω loop structure, a differential hydrogen bond network was observed, while the lysine residue responsible for linkage to growing pili was located at the same position in both structures, which indicated that switching of the hydrogen bond network in the Ω loop without changing the lysine position is advantageous for linkage to the backbone pilin FctA. The difference in direction of the proline-rich tail is potentially caused by a single residue located at the root of the proline-rich tail. Also, the FctB3 structure was found to be stabilized by intramolecular large hydrophobic interactions instead of an isopeptide bond. Comparisons of the FctB3 and FctA structures indicated that the FctA structure is more favorable for linkage to FctA. In addition, the heterodimer formation of FctB with Cpa or FctA was shown to be mediated by the putative chaperone SipA. Together, these findings provide an alternative FctB structure as well as insight into the interactions between pilin proteins., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Osteoclasts play a crucial role in bone homeostasis by forming resorption pits on bone surfaces, resulting in bone resorption. The osteoclast expression of Rab38 protein is highly induced during differentiation from macrophages. Here we generated mice with double knockout (DKO) of Rab38 and its paralogue, Rab32, to investigate the roles of these proteins in osteoclasts. Bone marrow-derived macrophages from Rab32/38 DKO mice differentiated normally into osteoclasts in vitro. However, DKO osteoclasts showed reduced bone resorption activity. These osteoclasts also demonstrated defective secretion of tartrate-resistant acid phosphatase and cathepsin K into culture medium. Furthermore, the plasma membrane localization of a3, an osteoclast-specific a subunit of V-ATPase, was abrogated in DKO mice, substantiating the reduced resorption activity. In vivo, Rab32- and Rab38-positive cells were attached to the bone surface. Eight-week-old DKO mice showed significantly thickened trabecular bones in micro-CT and histomorphometry analysis, as well as reduced serum levels of cross-linked C-telopeptide of type I collagen, indicating diminished bone resorption in vivo. In DKO male mice over 10 weeks of age, hyperostosis appeared at the talofibular syndesmosis, the distal junction of the tibia and fibula. Furthermore, middle-aged mice (10 to 12 months of age) exhibited kyphosis, which is not usually observed in wild-type male mice until around 24 months of age. These results indicate that Rab32 and Rab38 contribute to osteoclast function by supporting intracellular traffic, thereby maintaining normal bone homeostasis.Key words: Rab32, Rab38, osteoclast, lysosome-related organelle, secretory lysosome.

The tumor microbiome, a relatively new research field, affects tumor progression through several mechanisms. The Cancer Microbiome Atlas (TCMA) database was recently published. In the present study, we used TCMA and The Cancer Genome Atlas and examined microbiome profiling in head and neck squamous cell carcinoma (HNSCC), the role of the intratumoral microbiota in the prognosis of HNSCC patients, and differentially expressed genes in tumor cells in relation to specific bacterial infections. We investigated 18 microbes at the genus level that differed between solid normal tissue ( n = 22) and primary tumors ( n = 154). The tissue microbiome profiles of Actinomyces , Fusobacterium , and Rothia at the genus level differed between the solid normal tissue and primary tumors of HNSCC patients. When the prognosis of groups with rates over and under the median for each microbe at the genus level was examined, rates for Leptotrichia which were over the median correlated with significantly higher overall survival rates. We then extracted 35 differentially expressed genes between the over- and under-the-median-for -Leptotrichia groups based on the criteria of >1.5 fold and p < 0.05 in the Mann-Whitney U-test. A pathway analysis showed that these Leptotrichia -related genes were associated with the pathways of Alzheimer disease, neurodegeneration-multiple diseases, prion disease, MAPK signaling, and PI3K-Akt signaling, while protein-protein interaction analysis revealed that these genes formed a dense network. In conclusion, probiotics and specific antimicrobial therapy targeting Leptotrichia may have an impact on the prognosis of HNSCC.

FAM20C phosphorylates secretory proteins at S-x-E/pS motifs, and previous studies of Fam20C-dificient mice revealed that FAM20C played essential roles in bone and tooth formation. Inactivation of FAM20C in mice led to hypophosphatemia that masks direct effect of FAM20C in these tissues, and consequently the direct role of FAM20C remains unknown. Our previous study reported that osteoblast/odontoblast-specific Fam20C transgenic (Fam20C-Tg) mice had normal serum phosphate levels and that osteoblastic FAM20C-mediated phosphorylation regulated bone formation and resorption. Here, we investigated the direct role of FAM20C in dentin using Fam20C-Tg mice. The tooth of Fam20C-Tg mice contained numerous highly phosphorylated proteins, including SIBLINGs, compared to that of wild-type mice. In Fam20C-Tg mice, coronal dentin volume decreased and mineral density unchanged at early age, while the volume unchanged and the mineral density elevated at maturity. In these mice, radicular dentin volume and mineral density decreased at all ages, and histologically, the radicular dentin had wider predentin and abnormal apical-side dentin with embedded cells and argyrophilic canaliculi. Immunohistochemical analyses revealed that abnormal apical-side dentin had bone and dentin matrix properties accompanied with osteoblast-lineage cells. Further, in Fam20C-Tg mice, DSPP content which is important for dentin formation, was reduced in dentin, especially radicular dentin, which might lead to defects mainly in radicular dentin. Renal subcapsular transplantations of tooth germ revealed that newly formed radicular dentin replicated apical abnormal dentin of Fam20C-Tg mice, corroborating that FAM20C overexpression indeed caused the abnormal dentin. Our findings indicate that odontoblastic FAM20C-mediated phosphorylation in the tooth regulates dentin formation and odontoblast differentiation., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

A third-generation inhibitor of catechol O -methyltransferase (COMT), opicapone ( 1 ), has the 3-nitrocatechol scaffold as do the second-generation inhibitors such as entacapone ( 2 ) and tolcapone ( 3 ), but only 1 can sustainably inhibit COMT activity making it suitable for a once-daily regimen. These improvements should be attributed to the optimized sidechain moiety (oxidopyridyloxadiazolyl group) of 1 substituted at the 5-position of the 3-nitrocatechol ring. We analyzed the role of the sidechain moiety by solving the crystal structures of COMT/ S -adenosylmethionine (SAM)/Mg/ 1 and COMT/ S -adenosylhomocysteine (SAH)/Mg/ 1 complexes. Fragment molecular orbital (FMO) calculations elucidated that the dispersion interaction between the sidechains of Leu 198 and Met 201 on the β6β7-loop and the oxidopyridine ring of 1 were unique and important in both complexes. In contrast, the catechol binding site made a remarkable difference in the sidechain conformation of Lys 144. The ε-amino group of Lys 144 was outside of the catalytic pocket and was replaced by a water molecule in the COMT/SAH/Mg/ 1 complex. No nitrocatechol inhibitor has ever been reported to make a complex with COMT and SAH. Thus, the conformational change of Lys 144 found in the COMT/SAH/Mg/ 1 complex is the first crystallographic evidence that supports the role of Lys 144 as a catalytic base to take out a proton ion from the reaction site to the outside of the enzyme. The fact that 1 generated a complex with SAH and COMT also suggests that 1 could inhibit COMT twofold, as a typical substrate mimic competitive inhibitor and as a product-inhibition enhancer.

Background/purpose: In lower third molar (LM3) surgery, panoramic radiography (PAN) is important for the initial assessment of the anatomical association between LM3 and the inferior alveolar nerve (IAN). This study aimed to develop a deep learning model for the automated evaluation of the LM3-IAN association on PAN. Further, its performance was compared with that of oral surgeons using original and external datasets., Materials and Methods: In total, 579 panoramic images of LM3 from 384 patients in the original dataset were utilized. The images were divided into 483 images for the training dataset and 96 for the testing dataset at a ratio of 83:17. The external dataset comprising 58 images from an independent institution was used for testing only. The LM3-IAN associations on PAN were categorized into direct or indirect contact based on cone-beam computed tomography (CBCT). The You Only Look Once (YOLO) version 3 algorithm, a fast object detection system, was applied. To increase the amount of training data for deep learning, PAN images were augmented using the rotation and flip techniques., Results: The final YOLO model had high accuracy (0.894 in the original dataset and 0.927 in the external dataset), recall (0.925, 0.919), precision (0.891, 0.971), and f1-score (0.908, 0.944). Meanwhile, oral surgeons had lower accuracy (0.628, 0.615), recall (0.821, 0.497), precision (0.607, 0.876), and f1-score (0.698, 0.634)., Conclusion: The YOLO-driven deep learning model can help oral surgeons in the decision-making process of applying additional CBCT to confirm the LM3-IAN association based on PAN images., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2022 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Streptococcus pyogenes displays a wide variety of pili, which is largely dependent on serotype. A distinct subset of S. pyogenes strains that possess the Nra transcriptional regulator demonstrates thermoregulated pilus production. Findings obtained in the present study of an Nra-positive serotype M49 strain revealed involvement of conserved virulence factor A (CvfA), also referred to as ribonuclease Y (RNase Y), in virulence factor expression and pilus production, while a cvfA deletion strain showed reduced pilus production and adherence to human keratinocytes as compared with wild-type and revertant strains. Furthermore, transcript levels of pilus subunits and srtC2 genes were decreased by cvfA deletion, which was remarkable at 25°C. Likewise, both messenger RNA (mRNA) and protein levels of Nra were remarkably decreased by cvfA deletion. Whether the expression of other pilus-related regulators, including fasX and CovR, was subject to thermoregulation was also examined. While the mRNA level of fasX, which inhibits cpa and fctA translation, was decreased by cvfA deletion at both 37°C and 25°C, CovR mRNA and protein levels, as well as its phosphorylation level were not significantly changed, suggesting that neither fasX nor CovR is necessarily involved in thermosensitive pilus production. Phenotypic analysis of the mutant strains revealed that culture temperature and cvfA deletion had varied effects on streptolysin S and SpeB activities. Furthermore, bactericidal assay data showed that cvfA deletion decreased the rate of survival in human blood. Together, the present findings indicate that CvfA is involved in regulation of pilus production and virulence-related phenotypes of the serotype M49 strain of S. pyogenes., (© 2023 The Societies and John Wiley & Sons Australia, Ltd.)

We previously developed basic and extended models to predict inferior alveolar nerve injuries (IANI) after lower third molar (LM3) removal based on cone-beam computed tomography (CBCT) images. Although these models comprised predictors, including increased age and inferior alveolar canal-related CBCT factors, external validations were lacking. Therefore, this study externally validated these models and compared them with other related models based on their performance. Original and newly validated samples included patients who underwent LM3 removal following CBCT. Subsequently, 39 and 25 patients with IANI, then 457 and 295 randomly selected patients without IANI were chosen of the observed 1573 and 1052 patients, respectively. CBCT- and panoramic radiograph (PAN)-featured models were validated. Then, models' discrimination and calibration abilities were assessed using C-statistics and calibration plots, respectively. Brier scores were also quantified, after which logistic recalibration was achieved to optimize calibration, and a risk calculator was developed. During the external validation, the extended model exhibited the best C-statistic (0.822) and Brier score (0.064), whereas two CBCT- and two PAN-featured models showed lower performances with C-statistics (0.764, 0.706, 0.584, and 0.627) and Brier scores (0.069, 0.074, 0.075, and 0.072). Besides, all models showed a tendency to overpredict its high-risk range. However, recalibration of the extended model resulted in excellent calibration performance. CBCT-featured models, especially the extended model, conclusively showed a superior predictive performance to PAN models. Therefore, the risk calculator on the extended CBCT model is proposed to be a clinical decision-aid tool that preoperatively predicts IANI risk., (© 2022. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Ribonuclease (RNase) He1 is a small ribonuclease belonging to the RNase T1 family. Most of the RNase T1 family members are active at neutral pH, except for RNase Ms, U2, and He1, which function at an acidic pH. We crystallized and analyzed the structure of RNase He1 and elucidated how the acidic amino residues of the α1β3- (He1:26-33) and β67-loops (He1:87-95) affect their optimal pH. In He1, Ms, and U2, the hydrogen bonding network formed by the acidic amino acids in the β67-loop suggested that the differences in the acidification mechanism of the optimum pH specified the function of these RNases. We found that the amino acid sequence of the β67-loop was not conserved and contributed to acidification of the optimum pH in different ways. Mutations in the acidic residues in He1 promoted anti-tumor growth activity, which clarified the role of these acidic amino residues in the binding pocket. These findings will enable the identification of additional targets for modifying pH-mediated enzymatic activities.

Background: The extensive loss of teeth and surrounding tissues due to mandibulectomy for an oral tumor not only impacts negatively on appearance, but also often causes various functional disorders, decreasing quality of life (QOL). In the present case, reconstruction with a scapular flap was carried out along with segmental mandibulectomy, aiming for functional restoration through restoration-driven implant treatment. A good outcome was obtained, with improvement of masticatory function and QOL following the prosthetic treatment., Case Presentation: The patient was a 37-year-old woman diagnosed with ossifying fibroma in the left side of the mandible. Segmental mandibulectomy and reconstruction with a scapular flap were carried out. Implant diagnostic simulation was performed, and based on the result, secondary reconstruction using a particulate cancellous bone and marrow graft was carried out by an oral surgeon. After wound healing was complete, implant placement was performed twice, and the final prosthodontic treatment was completed. Masticatory performance and maximum bite force, which are indices of masticatory function, were improved from before to after prosthetic treatment. In addition, oral health-related QOL was improved from before to after prosthetic treatment., Conclusion: In the present case, restoration-driven implant treatment was performed in a patient following segmental mandibulectomy for a mandibular tumor, with a good outcome. Planning the treatment measures with a focus on the final prosthetic vision can lead to improvement of oral function in patients with extensive mandibular defects., (© 2022. The Author(s).)

Maxillary gingival squamous cell carcinoma (MGSCC) occurs rather infrequently, compared to tongue and mandibular gingival carcinomas, among the cancers of the oral cavity. Therefore, significant numbers of MGSCC cases have not been statistically analysed. The aim of this study is to clarify the prognostic factors for MGSCC. We performed the statistical analysis of 90 MGSCC cases primarily treated in our department from 1999 to 2014. The patients (male: 36, female: 54) were aged between 38 and 93 years, and the mean age was 68.7 years. The number of patients in each tumour stage according to the TNM classification was as follows: T1: 15 cases, T2: 32 cases, T3: 13 cases, and T4: 30 cases. Forty-two patients were treated only by surgery, 5 only by radiotherapy, 3 by preoperative radiotherapy and surgery, and 40 patients were treated by combination therapy with preoperative chemoradiotherapy and surgery. Neck dissections were performed in 40 cases including 29 cases (11 primary and 18 secondary cases) of histopathologically diagnosed lymph node metastases. Extranodal extension was found in 74.3% cases with metastatic lymph nodes. The 5-year overall survival rate was 81.9%. In univariate analysis, the site of occurrence, stage of tumour, lymph node metastasis, and treatment contributed to the 5-year survival rate. Multivariate analysis demonstrated that the site of occurrence (posterior region) was an independent prognostic factor. Seventeen deaths occurred due to the primary disease, while three deaths were caused by other diseases. The posterior region cancers, according to the classification based on site of occurrence, were independent predictors of poor 5-year overall survival rate., Competing Interests: Conflict of interestsThe authors have no conflicts of interest to declare that are relevant to the content of this article., (© Association of Otolaryngologists of India 2021.)

Oral squamous cell carcinoma (OSCC) can disturb oral function and quality of life and is associated with poor survival, likely due to the development of cervical lymph node metastases. Epithelial-mesenchymal transition (EMT) is a process in which cells acquire molecular alterations that facilitate cell motility and invasion, and has been associated with tumor metastasis. EMT changes also play important roles in the induction of lymph node metastasis in OSCC. GATA6 is known as the earliest marker of the primitive endoderm lineages. GATA6 inhibits de-differentiation and EMT in human pancreatic ductal adenocarcinoma cells and promotes EMT. However, in OSCC, the expression and function of GATA6 in EMT and lymph node metastasis remains unclear. Therefore, this study aimed to clarify the targets of GATA6 in OSCC cells and whether the change in GATA6 expression affects EMT in OSCC cells, as well as the association between GATA6 and lymph node metastasis. The results showed that GATA6 knockdown OSCC cells promoted EMT and increased lymph node metastasis compared with control cells, whereas the overexpression of GATA6 inhibited the induction of EMT and reduced lymph node metastasis. In addition, annexin A10 (ANXA10) which is the largest type of Ca 2+ -regulated phospholipid-binding protein in eukaryotic cells was detected as a target gene for GATA6 and ANXA10 suppressed Vimentin expression in EMT in OSCC. Therefore, the GATA6/ANXA10 cascade may be a potential therapeutic approach for the treatment of lymph node metastases in OSCC patients., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The mammalian target of rapamycin (mTOR)-composed of multiple complexes, including mTOR complex 1/2 (mTORC1/2)-is a serine-threonine kinase that regulates embryonic development. The transcription factor, hypoxia-inducible factor-1α (HIF-1α), is also involved in embryonic development. As the relationship between mTOR and HIF-1α during embryonic development remains unclear, we investigated the relationship between the two using ex vivo submandibular salivary gland organ cultures. When the expression of HIF-1α increased under hypoxic conditions (1% O 2 ), the expression of mTOR signaling pathway-related proteins decreased. Conversely, when the expression of HIF-1α decreased, the expression of mTOR signaling pathway-related proteins increased. These results indicate a strong relationship between HIF-1α and the mTOR signaling pathway. For the first time, we clarified that HIF-1α negatively regulates the mTOR signaling pathway and suppresses salivary gland development under 1% O 2 using small molecules. Our research provides new insights into the relationship between HIF-1α and the mTOR signaling pathway in embryonic organ development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Pleomorphic adenoma (PA) is a localized tumor that presents pleomorphic or mixed characteristics of epithelial origin and is interwoven with mucoid tissue, myxoid tissue, and chondroid masses. The literature reported that PA most often occurs in adults aged 30-60 years and is a female predilection; the exact etiology remains unclear. Epithelial-mesenchymal transition (EMT) is the transdifferentiation of stationary epithelial cells primarily activated by a core set of transcription factors (EMT-TFs) involved in DNA repair and offers advantages under various stress conditions. Data have suggested that EMTs represent the basic principle of tissue heterogeneity in PAs, demonstrating the potential of adult epithelial cells to transdifferentiate into mesenchymal cells. It has also been reported that multiple TFs, such as TWIST and SLUG, are involved in EMT in PA and that SLUG could play an essential role in the transition from myoepithelial to mesenchymal cells. Given this background, this review aims to summarize and clarify the involvement of EMT in the development of PA, chondrocyte differentiation, and malignant transformation to contribute to the fundamental elucidation of the mechanisms underlying EMT.