A Qualitative Ethnographic Case Study Exploring the Hispanic/Latinx Interpretations of Collegiate Aviation Safety Culture

Through a combination of ethnographic principles and a qualitative case study structure, this study strives to understand how Hispanic/ Latinx aviation students perceive the current aviation safety culture in their flight training program. Grounded in the reciprocal safety culture model, the researchers attempt to answer how does Hispanic/Latinx culture influence perceptions towards commitment to aviation safety? and what are Hispanic/Latinx students’ perceptions of their ability to influence aviation safety culture? Three major themes emerged from the data: behavioral signs of safety culture at the collegiate level, obstacles to a sound safety culture, and methods to improve the safety culture. Moreover, factors such as individualism, masculinity, access to economic resources, and language were prevalent in the findings on how Hispanic aviation students perceive their collegiate flight training safety culture. Future studies should explore the perception of different ethnic groups of aviation students at various geographical locations to identify any added layers of threat, behavioral attitudes, and safety compromises related to flight training

Electrophysiologic features of SYT2 mutations causing a treatable neuromuscular syndrome

Objectives: To describe the clinical and electrophysiologic features of synaptotagmin II (SYT2) mutations, a novel neuromuscular syndrome characterized by foot deformities and fatigable ocular and lower limb weakness, and the response to modulators of acetylcholine release. Methods: We performed detailed clinical and neurophysiologic assessment in 2 multigenerational families with dominant SYT2 mutations (c.920T>G [p.Asp307Ala] and c.923G>A [p.Pro308Leu]). Serial clinical and electrophysiologic assessments were performed in members of one family treated first with pyridostigmine and then with 3,4-diaminopyridine. Results: Electrophysiologic testing revealed features indicative of a presynaptic deficit in neurotransmitter release with posttetanic potentiation lasting up to 60 minutes. Treatment with 3,4-diaminopyridine produced both a clinical benefit and an improvement in neuromuscular transmission. Conclusion: SYT2 mutations cause a novel and potentially treatable complex presynaptic congenital myasthenic syndrome characterized by motor neuropathy causing lower limb wasting and foot deformities, with reflex potentiation following exercise and a uniquely prolonged period of posttetanic potentiation.National Institutes of Health (U.S.) (NIH grant NS40296)JPB Foundatio

Synaptotagmin 2 Mutations Cause an Autosomal-Dominant Form of Lambert-Eaton Myasthenic Syndrome and Nonprogressive Motor Neuropathy

Synaptotagmin 2 is a synaptic vesicle protein that functions as a calcium sensor for neurotransmission but has not been previously associated with human disease. Via whole-exome sequencing, we identified heterozygous missense mutations in the C2B calcium-binding domain of the gene encoding Synaptotagmin 2 in two multigenerational families presenting with peripheral motor neuron syndromes. An essential calcium-binding aspartate residue, Asp307Ala, was disrupted by a c.920A>C change in one family that presented with an autosomal-dominant presynaptic neuromuscular junction disorder resembling Lambert-Eaton myasthenic syndrome. A c.923C>T variant affecting an adjacent residue (p.Pro308Leu) produced a presynaptic neuromuscular junction defect and a dominant hereditary motor neuropathy in a second family. Characterization of the mutation homologous to the human c.920A>C variant in Drosophila Synaptotagmin revealed a dominant disruption of synaptic vesicle exocytosis using this transgenic model. These findings indicate that Synaptotagmin 2 regulates neurotransmitter release at human peripheral motor nerve terminals. In addition, mutations in the Synaptotagmin 2 C2B domain represent an important cause of presynaptic congenital myasthenic syndromes and link them with hereditary motor axonopathies.National Institutes of Health (U.S.) (NIH Grant NS40296)Picower Institute for Learning and Memory (Picower Neurological Disease Research Fund)JPB Foundatio