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Regenerative medicine utilizes stem cells to repair damaged tissues by replacing them with their differentiated cells and activating the body's inherent regenerative abilities. Mesenchymal stem cells (MSCs) are adult stem cells that possess tissue repair and regenerative capabilities and immunomodulatory properties with a much lower risk of tumorigenicity, making them a focus of numerous clinical trials worldwide. MSCs primarily exert their therapeutic effects through paracrine effects via secreted factors, such as cytokines and exosomes. This has led to increasing interest in cell-free therapy, where only the conditioned medium (also called secretome) from MSC cultures is used for regenerative applications. However, MSCs face certain limitations, including cellular senescence, scarcity, donor heterogeneity, complexity, short survival post-implantation, and regulatory and ethics hurdles. To address these challenges, various types of immortalized MSCs (ImMSCs) capable of indefinite expansion have been developed. These cells offer significant promise and essential tools as a reliable source for both cell-based and cell-free therapies with the aim of translating them into practical medicine. However, the process of immortalization, often involving the transduction of immortalizing genes, poses potential risks of genetic instability and resultant malignant transformation. Cell-free therapy is particularly attractive, as it circumvents the risks of tumorigenicity and ethical concerns associated with live cell therapies. Rigorous safety tests, such as monitoring chromosomal abnormalities, are critical to ensure safety. Technologies like inducible or suicide genes may allow for the controlled proliferation of MSCs and induce apoptosis after their therapeutic task is completed. This review highlights recent advancements in the immortalization of MSCs and the associated risks of tumorigenesis. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the usefulness of saturated salt solution-embalmed cadavers for oral surgical skills training related to bone graft harvesting. Two half-day surgical skills training workshops were held at the Tokyo Medical University utilizing eight cadavers embalmed with the saturated salt solution. A total of 22 participants including oral surgeons, residents, and dentists attended the workshop. Surgical training consisted of six procedures related to intraoral and extraoral bone harvesting. The participants were surveyed to assess self-confidence levels for each surgical procedure before and after completion of each workshop. The Wilcoxon signed-rank test was used to compare the differences between each median score before and after the workshop. There were statistically significant increases in the self-assessed confidence scores in bone harvesting procedures for the zygomatic bone (P = 0.003), maxillary tuberosity (P = 0.002), and other sites (P < 0.001). The anatomical features of saturated salt solution-embalmed cadavers were also examined. The textures of the oral mucosa and skin were similar to those of living individuals. The structure of bone tissues was well-preserved and the hardness was realistic. Consequently, all procedures were performed with sufficient realism. The saturated salt solution method has a relatively low cost of preparation and storage, and almost no odor. The authors suggest that saturated salt solution-embalmed cadavers could provide a new model for oral surgical skills training in bone harvesting.

Objectives: Immunotherapy with nivolumab for patients with recurrent/metastatic oral squamous cell carcinoma has not been evaluated. Here, we aimed to examine the efficacy, safety, and prognostic factors of nivolumab in these patients. Materials and Methods: This multicenter retrospective observational study involved patients who received nivolumab between April 2017 and June 2019. The patient characteristics were evaluated for association with progression‐free and overall survival. Progression‐free and overall survival rates were calculated; parameters that were significant in the univariate analysis were used as explanatory variables. Independent factors for progression‐free and overall survival were identified using multivariate analysis. Results: Totally, 143 patients were included. The overall response and disease control rates were 27.3% and 46.2%, respectively. The median, 1‐ and 2‐year progression‐free survival rates were 2.7 months, 25.4%, and 19.2%, respectively; those for overall survival were 11.2 months, 47.3%, and 33.6%, respectively. The independent factors affecting progression‐free survival were performance status and immune‐related adverse event occurrence, whereas those affecting overall survival were performance status, target disease, and number of previous lines of systemic cancer therapy. Eight patients reported grade ≥3 immune‐related adverse events. Conclusion: Nivolumab was effective for recurrent/metastatic oral squamous cell carcinoma treatment and was well tolerated by patients. [ABSTRACT FROM AUTHOR]

Cases of extramedullary multiple myeloma occurring in the oral cavity are rare. Herein, we present a unique case of extramedullary disease occurring twice in the oral cavity. A 72-year-old woman was diagnosed with multiple myeloma and was undergoing melphalan and prednisone therapy, along with thalidomide. The patient visited our hospital with a complaint of swelling of the left mandibular gingiva and an outward mass located on the buccal side of the left mandibular second molar. Radiographic and computed tomography examinations showed no bone resorption disease. Biopsy was performed for a definitive diagnosis, which confirmed extramedullary multiple myeloma. Radiation therapy was administered, and the lesion disappeared after 2 months. However, 2 months thereafter, a tumor appeared in the upper right maxillary gingiva, which disappeared following another round of radiation therapy. Subsequently, an extramedullary tumor developed systemically. The patient died due to poor management of the underlying disease. The development of extramedullary tumors is associated with a low survival rate, which should be given crucial consideration in treatment decisions. [ABSTRACT FROM AUTHOR]

Glutaric acidemia type 1 (GA1) is an autosomal recessive disorder of organic acid metabolism that is caused by a defect in glutaryl CoA dehydrogenase. The frequency of this disease is estimated to be approximately 1 in 100,000 births globally. This disease is the primary target of newborn mass screening (MS). Neurological sequelae and treatment must be continued throughout life. We performed extraction of a supernumerary tooth in a patient with GA1. Tooth extraction in GA1 patients has not been reported earlier. A 7-year-old Japanese boy was referred to our department for maxillary supernumerary tooth extraction. A diagnosis of GA1 was made based on the high serum C5-DC and urinary glutaric acid levels, and analysis of the GCDH gene revealed a mutation. The patient was treated with carnitine and lysine restriction and was in good general condition, with no neurological abnormalities. Further, supernumerary tooth extraction was performed under local anesthesia. Preoperatively, we confirmed the absence of hyperammonemia and metabolic acidosis, and the patient was treated with glucose infusion in consultation with a pediatrician. No abnormal findings were observed intraoperatively or postoperatively and wound healing was satisfactory one month later. [ABSTRACT FROM AUTHOR]