Neuromuscular synapses in an androgen-sensitive muscle of sexually mature male mice were repeatedly observed over several-month intervals in normal animals and in animals in which testosterone levels were manipulated. In normal bulbocavernosus muscles, pre- and postsynaptic regions of neuromuscular junctions enlarge as muscle fibers grow. After castration, junctional area decreased in parallel with muscle fiber atrophy. When testosterone was resupplied to castrated animals, junctions that previously decreased in size then enlarged in parallel with muscle fiber hypertrophy. Surprisingly, these size changes occurred without loss or addition of motor nerve terminal branches or acetylcholine (ACh) receptor regions. Rather, each nerve terminal branch and underlying receptor region became smaller following castration and reenlarged following testosterone treatment. Several lines of evidence argued that the size changes observed after castration and testosterone treatment were secondary to shrinkage and stretching of the postsynaptic muscle fiber membrane. Following castration, the spaces between synaptic regions decreased in size at the same time and to a similar extent as the regions themselves. Following testosterone replacement, the spaces between synaptic regions expanded and each existing ACh receptor region enlarged. Ultrastructural analysis showed that there was no loss or addition of postsynaptic secondary junctional folds in the muscle fiber membrane (where ACh receptors are located) as junctions shrank and expanded. Rather, folds became more densely packed as muscle fibers atrophied following castration and less densely packed as muscle fibers hypertrophied following testosterone replacement. From these studies of the bulbocavernosus muscle, as from our previous studies of the sternomastoid muscle, we conclude that neuromuscular junction size is directly coupled to muscle fiber size. Androgens modulate muscle fiber volume directly, leading to a change in the surface area of the muscle fiber membrane, which in turn causes the postsynaptic specializations to shrink or expand. The concomitant shrinkage and stretching of motor nerve terminals that we observed can only be accounted for by their adhesion to postsynaptic specializations that are also changing size. Thus adhesion, rather than an interchange of diffusible factors, trophic or otherwise, is likely to be the primary determinant of coordinated pre- and postsynaptic enlargement in growing mammalian skeletal muscles.
Introduction: Background: The Centers for Disease Control (CDC) notes a 154 percent increase in telemedicine use amongst healthcare providers between March 2019 and March 2020. While not formally incorporated into the Liaison Committee on Medical Education (LCME) accreditation standards, the Association of American Medical Colleges (AAMC) has made the provision of telemedicine services as an entrustable professional activity (EPA). Given the growth of telemedicine use, medical student comfort with the formalized EPAs was explored in this study.Methods: An IRB-approved 17-question, anonymous survey was created based on the AAMC’s EPAs and administered to students at Northeast Ohio Medical University (NEOMED) over four weeks. The primary outcome of this study is to assess medical students’ self-reported telemedicine comfort levels.Results: The response rate was 141 students (22%). 57% of students describe that they were able to create equally as effective a therapeutic alliance using telemedicine compared to in-person appointments. 57% and 53% of students, respectively, felt they were able to gather information and diagnose patients using telemedicine compared to in person. 74% of respondents wish that telemedicine was formally taught in school. Conclusion: Most students believe they can effectively gather essential information, and counsel patients via telemedicine, but there was a notable decrease in confidence for medical students when comparing telemedicine and in-person care directly. Despite the EPAs created by the AAMC, students are not self-reporting the same comfort level with telemedicine as they are with in-person patient visits, so there are further opportunities for improvements in the telemedicine medicine school curriculum.Trial Registration: IRB Exemption approved on 02/28/22 by Northeast Ohio Medical University
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.