Olfactory exposure to males, including men, causes stress and related analgesia in rodents.

We found that exposure of mice and rats to male but not female experimenters produces pain inhibition. Male-related stimuli induced a robust physiological stress response that results in stress-induced analgesia. This effect could be replicated with T-shirts worn by men, bedding material from gonadally intact and unfamiliar male mammals, and presentation of compounds secreted from the human axilla. Experimenter sex can thus affect apparent baseline responses in behavioral testing.

Advancements in tooth autotransplantation.

BACKGROUND: Tooth autotransplantation (AT) involves the surgical relocation of a tooth from 1 site in the mouth to another site within the same patient. This approach is a good option in a growing patient when dental implant placements or fixed bridges are not suitable and when preserving natural teeth is a priority. Tooth AT is a complex procedure that requires specialized skills from a multidisciplinary team with careful patient and tooth selection and treatment planning. TYPES OF STUDIES REVIEWED: The authors provided a review of the state of knowledge and research on tooth AT and presented a case scenario and barriers to adoption, with a focus on the United States. RESULTS: Success rates for tooth AT can vary depending on several factors, including the patient's overall health, specific tooth involved, skill of the dental surgeon, and postoperative care provided. Long-term outcomes of autotransplanted teeth have been cited in the literature with impressive longitudinal follow-up spanning up to 26 years. Results of several systematic reviews showed survival rates from 75% through 98%. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Adoption of tooth AT has grown over the years, owing to advancements in dental techniques, improved patient outcomes, and increased awareness among both dentists and patients. Increasing awareness and availability of tooth AT to replace missing teeth can provide a natural and functional alternative to traditional prosthetic options. Tooth AT helps preserve the alveolar bone in growing patients and can offer excellent esthetic and functional outcomes.

Cage-lid hanging behavior as a translationally relevant measure of pain in mice.

ABSTRACT: The development of new analgesic drugs has been hampered by the inability to translate preclinical findings to humans. This failure is due in part to the weak connection between commonly used pain outcome measures in rodents and the clinical symptoms of chronic pain. Most rodent studies rely on the use of experimenter-evoked measures of pain and assess behavior under ethologically unnatural conditions, which limits the translational potential of preclinical research. Here, we addressed this problem by conducting an unbiased, prospective study of behavioral changes in mice within a natural homecage environment using conventional preclinical pain assays. Unexpectedly, we observed that cage-lid hanging, a species-specific elective behavior, was the only homecage behavior reliably impacted by pain assays. Noxious stimuli reduced hanging behavior in an intensity-dependent manner, and the reduction in hanging could be restored by analgesics. Finally, we developed an automated approach to assess hanging behavior. Collectively, our results indicate that the depression of hanging behavior is a novel, ethologically valid, and translationally relevant pain outcome measure in mice that could facilitate the study of pain and analgesic development.