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Loss of biodiversity is a serious concern, and amphibians are particularly threatened. Most small salamanders in Japan are endangered. Distributional information is fundamental to the conservation of these rare species; however, small salamanders are generally difficult to locate or catch. Environmental DNA analysis is an effective survey method for monitoring such rare species. The conventional polymerase chain reaction (PCR) method, which combines PCR amplification with subsequent electrophoresis, and the real-time PCR method, which uses fluorescent material, are commonly used for this purpose. In this study, a comparison of these two detection methods was conducted using a rare salamander species, Hynobius boulengeri, as a model case. We compared three points: (i) detection sensitivity, (ii) influence of environmental factors related to detection, and (iii) time and financial costs of the two methods. To perform this comparison, we developed a real-time PCR detection assay, conducted field surveys, and compared the time and financial costs of conventional and real-time PCR methods. The comparison showed no statistical difference in the detection sensitivity from field samples, and the effects of environmental factors tended to be similar. In addition, the financial cost was lower for the conventional PCR method while the time cost was lower for the real-time PCR method. Therefore, selecting eDNA detection methods based on objectives, time, and financial costs will promote efficient monitoring and contribute to the conservation of rare species., (© 2023. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Background: The purpose of this retrospective study was to accumulate data regarding the quality of postoperative neurosensory function after inferior alveolar nerve (IAN) transposition for dental implant placement., Methods: The study included seven consecutive patients who underwent IAN transposition surgery for the insertion of a dental implant into the atrophic posterior mandible. Of these, six patients (seven sides) were available for long-term assessment of postoperative IAN function. Neurosensory disturbance of the IAN was assessed objectively using the modified SW perception test reported by Semmes and Weinstein. In addition, the quality of nerve paralysis was assessed according to the criteria reported by Highet., Results: The median follow-up time was 49 months (range 12-105 months). No implant loss was observed during the follow-up. All patients experienced numbness immediately and the days after surgery. Complete recovery of neural function was observed on two sides; weak hypoesthesia was observed on two sides, moderate hypoesthesia on two sides, and severe hypoesthesia on one side. However, only one patient expressed concern about IAN function., Conclusions: IAN transposition is a useful method for placing implants in the atrophic posterior mandible. However, the procedure is complicated, with the possibility of some degree of neurosensory disturbance, although in most of our cases, it resolved within a clinically acceptable period.