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Background/purpose: Sphingosine-1-phosphate (S1P) exhibits receptor-mediated physiological effects by facilitating the differentiation of mesenchymal stem cells toward the osteoblast lineage. This study aimed to determine the effect of S1P on odontogenic differentiation of mouse immortalized stem cells of dental apical papilla (iSCAP) and assess the distribution of the S1P receptor 1 (S1PR1) in the apical papilla and the root canal wall of immature rat molars., Materials and Methods: Immunostaining for S1PR1 was conducted at the apex of the rat mandibular first molar and within the root canal wall. The iSCAP was treated with S1P and bone morphogenetic protein (BMP)-9 (for comparison), and the expression levels of the odontogenic differentiation marker were evaluated via real-time reverse-transcriptase quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Mineralization and lipid droplet formation were evaluated via Alizarin red and Oil red O staining., Results: S1PR1-positive cells were expressed in areas of both apical papilla and dentin-pulp interface of root canal wall. During the odontogenic differentiation of iSCAP, S1P and BMP-9 increased the expression of the differentiation marker mRNA and secreted proteins including dentin sialophosphoprotein, dentin matrix phosphoprotein 1, and matrix extracellular phosphoglycoprotein. The S1PR1 signaling pathway is involved in the action of S1P, but not that of BMP-9. S1PR1 signaling also facilitated mineralization in iSCAP and suppressed the differentiation of these cells into adipocytes., Conclusion: S1P induced odontogenic differentiation of iSCAP through S1PR1. Furthermore, S1PR1-positive cells were expressed in the apical papilla of immature rat molars and in the dentin-pulp interface where odontoblast-like cells exist., Competing Interests: The authors have no conflicts of interest to declare., (© 2024 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

A deep eutectic solvent (DES) composed of isostearic acid and TOPO was newly found out and investigated for selective recovery of scandium. The four elements used in this study are scandium, iron, yttrium, and aluminum. It was difficult to separate the four elements owing to the overlap of extraction behavior when isostearic acid or TOPO alone in toluene was used, respectively. However, scandium was able to be selectively extracted from other metals using DES prepared by 1:1 mol ratio of isostearic acid and TOPO without toluene. In DES consisting of isostearic acid and TOPO, synergistic and blocking effects with three extractants acted on the extraction selectivity for scandium. Both effects are proved also from the fact that scandium was easily stripped with diluted acidic solutions such as 2 M HCl and H 2 SO 4 . Thus, DES extracted selectively scandium and back-extraction was easily achieved. In order to elucidate these phenomena above, the extraction equilibria of Sc(III) using DES dissolved in toluene was investigated in detail. The extraction mechanism of scandium by DES in toluene indicates that the extracted chemical species vary with pH, and that trivalent scandium is extracted by forming stable metal complexes with DESs consisting of five molecules of isostearic acid and five molecules of TOPO., (© 2023. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Objectives: This study retrospectively investigated the prevalence and clinical features of trephine syndrome, which is a late complication of craniectom, in patients who underwent craniectomy decompression., Methods: Trephine syndrome was defined as an increase of ≥2 points in the functional independent measure (FIM) score at 7 days after cranioplasty compared with that 3 days before cranioplasty. Patients who underwent craniectomy at Kawasaki Medical School Hospital between January 1, 2010, and March 15, 2020, were included in the study., Results: During the observation period, 102 patients underwent craniectomy decompression; 71 of them later underwent cranioplasty. In total, 12 and 59 patients were assigned to the trephine and non-trephine syndrome groups, respectively. The patients in the trephine syndrome group were significantly younger than those in the non-trephine syndrome group (P<0.05). The mean durations±standard deviations (in days) from craniectomy decompression to cranioplasty were 57.1±38.9 and 83.6±69.3 for the trephine and non-trephine syndrome groups, respectively (P<0.05). Improvements in the FIM motor scores were greater than the improvements in the cognitive scores for all but one case (P<0.05). The frequency with which patients experienced exacerbation (worsened consciousness and sudden anisocoria) after hospitalization was significantly higher in the trephine syndrome group than in the non-trephine syndrome group (P<0.05)., Conclusions: Performing cranioplasty as early as possible in young patients may lead to functional improvement. In the trephine syndrome group, the improvement in motor FIM score was greater than that of the cognitive score. Moreover, post-hospitalization exacerbation was more frequent in the trephine syndrome group., Competing Interests: CONFLICTS OF INTEREST: The authors declare that they have no conflicts of interest., (2022 The Japanese Association of Rehabilitation Medicine.)

Objective: Acetaminophen is an analgesic that shows efficacy in postoperative pain relief in children. Many drugs such as opioids, non-steroidal anti-inflammatory drugs, and/or acetaminophen have been used in paediatric skin laser irradiation surgery for postoperative pain relief. However, acetaminophen has some advantages over opioids, and opioids are being used less often. We aimed to demonstrate the effectiveness of intravenous (IV) acetaminophen during surgery for postoperative pain in paediatric skin laser irradiation., Methods: The present study is a small, prospective, double-blinded, randomized controlled trial. Paediatric patients (1-12 years old with an American Society of Anesthesiologists physical Status I and II), scheduled for skin laser irradiation for a nevus or haemangioma between October 2014 and April 2016 were randomized into the acetaminophen (n=9) and placebo (saline, n=8) groups. The observational face scale (FS) and the Behavioural Observational Pain Scale (BOPS) scores were recorded on emergence from anaesthesia, and 1, 2, and 4 hr post-surgery., Results: Patient characteristics were not significantly different except with regard to the irradiation area and surgery time. The observational FS and BOPS scores of the acetaminophen group were lower than those of the placebo group; median (minimum-maximum) at each recording time: 1 (0-2) - 0 (0-2) - 0 (0-1) - 0 (0-2) vs. 2 (0-4) - 0 (0-2) - 0 (0-2) - 0 (0-1) and 1 (0-3) - 1 (0-3) - 1 (0-2) - 0 (0-1) vs. 2 (0-4) - 3 (0-5) - 1 (0-4) - 0 (0-3), p=0.07 and p=0.003, respectively. No differences in post-surgical analgesic use or adverse events were observed., Conclusion: In this study, we showed that the IV acetaminophen group had lower observational FS and BOPS scores in the early postoperative period; however, further studies including a large number of patients are required to confirm our findings., Competing Interests: Conflict of Interest: The authors have no conflicts of interest to declare.

Background: Mandibular reconstruction is performed after segmental mandibulectomy, and precise repositioning of the condylar head in the temporomandibular fossa is essential for maintaining preoperative occlusion., Methods: In cases without involvement of soft tissue around the mandibular bone, the autopolymer resin in a soft state is pressed against the lower border of the mandible and buccal and lingual sides of the 3D model on the excised side. After hardening, it is shaved with a carbide bar to make the proximal and distal parts parallel to the resected surface in order to determine the direction of mandibular resection. On the other hand, in cases that require resection of soft tissue around the mandible such as cases of a malignant tumor, right and left mandibular rami of the 3D model are connected with the autopolymer resin to keep the preoperative position between proximal and distal segments before surgical simulation. The device is made to fit the lower border of the anterior mandible and the posterior border of the mandibular ramus. The device has a U-shaped handle so that adaptation of the device will not interfere with the soft tissue to be removed and has holes to be fixed on the mandible with screws., Results: We successfully performed the planned accurate segmental mandibulectomy and the precise repositioning of the condylar head by the device., Conclusions: The present technique and device that we developed proved to be simple and useful for restoring the preoperative condylar head positioning in the temporomandibular fossa and the precise resection of the mandible.

To clarify the clinical features of cochlear reimplantation and surgical changes in auditory performance, we retrospectively reviewed 10 of 252 cochlear implantation surgeries-6 adults and 4 children-among 129 children and 123 adults done between April 1987 and May 2009. Mean duration from initial implantation to reimplantation was 50.3 months in children and 89 months in adults, most commonly due to hard failure and implant exposure/infection (33%) in children and to hard failure (75%) in adults. The initial device implanted was the Nucleus multichannel implant (CI22M, CI24M, or CI24R). The second implant in 7 was the same or an upgrade of the same manufacturer's device, and in 2 children the HiRes 90K (Hifocus 1j) and in 1 adult the Clarion 1.2. Full initial and reinsertion succeeded in 8 cases but reinsertion proved difficult in 2 due to severe intracochlear granulation and osteoneogenseis. Auditory performance analyzed in 7 cases was mostly equal to or better than before reimplantation, although differences were not statistically significant. Reinsertion is rarely difficult, but electrode choice is important in preparing for difficult reinsertion. Post reinsertion auditory performance is satisfactory with some exceptions.

Background: After successful trials of tracheal reconstruction using mesh-type prostheses in canine models, the technique has been applied clinically to human patients since 2002. To enhance tissue regeneration, we have applied a new tissue engineering approach to this mesh-type prosthesis., Methods: The prosthesis consists of a polypropylene mesh tube reinforced with a polypropylene spiral and atelocollagen layer. The cervical tracheas of 18 beagle dogs were replaced with the prosthesis. The collagen layer was soaked with peripheral blood in 6 of the dogs, with bone marrow aspirate in another 6, and with autologous multipotential bone marrow-derived cells (mesenchymal stem cells) in another 6. The dogs were humanely killed at 1 to 12 months after the operation., Results: All 18 dogs survived the postoperative period. Bronchoscopically, 3 of 4 dogs in the peripheral blood group showed stenosis, whereas no stenosis was evident in all 8 of the dogs in the bone marrow and mesenchymal stem cell groups 6 months after the operation. Faster epithelialization and fewer complications, such as mesh exposure and luminal stenosis, were observed in these two groups than in the peripheral blood group. Histologically, the cells from autologous bone marrow were found to proliferate into the tracheal tissue during the first month. Cilial movement in these two groups was faster than that in the peripheral blood group and recovered to 80% to 90% of the normal level., Conclusions: Bone marrow aspirate and mesenchymal stem cells enhance the regeneration of the tracheal mucosa on this prosthesis. This in situ tissue engineering approach may facilitate tracheal reconstruction in the clinical setting.

Because of the limitations of the present medicine, regenerative medicine has greatly been hoped. Regenerative medicine is an exciting emerging branch of medicine in which cell and tissue based therapies are applied to the treatments of disease. This has been supported by the development of tissue engineering that was a complex of medicine and engineering. Tissue engineering applies the principles and methods of engineering, material science, and cell and molecular biology toward the development of viable substitutes which restore, maintain, or improve the function of human tissues. According to the doctrine of tissue engineering, tissues and organs can be regenerated by manipulating three elements: cells, scaffolds and regulation factors. Understanding and manipulating the complex relationship among these elements, however, represents the great challenge for researches and doctors who engage in regenerative medicine. On the other hand, clinical applications of it have not made progress yet except limited tissues and organs. Especially, few clinical studies have reported in the fields of otolaryngology, head and neck regions. In our research group, clinical applications in these fields based on the new concept of in situ tissue engineering have been started from 2002 after approval of the ethical committee. Tissues and/or organs for clinical applications at present are trachea, cricoid cartilage, mastoid air cells, and, peripheral nerves including facial nerve, recurrent laryngeal nerve, chorda tympani nerve and so on. This article describes the researches and clinical studies at present and in the near future of regenerative medicine in the fields of otolaryngology, head and neck regions.