The development of identified mammalian spinal motoneurones in culture

Motoneurones are one of the first type of neurone to be generated in the mammalian spinal cord during development. After generation and migration they settle in the lateral part of the ventral spinal cord and produce axons that will innervate specific muscles. In vivo and in vitro studies have well established that during embryonic life the survival of motoneurones and their final number depend critically on their muscle-targets. It has been suggested that other neurones and non-neuronal cells may affect their survival, but whether they also regulate the development and growth of motoneurones, is not known. In the present study, the development, growth, and survival of spinal mammalian embryonic motoneurones in culture were studied, paying special attention to changes in size, neurite growth and branching. The effects of different non-neuronal cells on growth and survival were studied. For these purposes a culture system of dissociated well identified embryonic motoneurones from rat spinal cord was firstly developed. Embryonic spinal motoneurones were retrogradely labelled with fiuorochromes, and labelled motoneurones were identified by the use of a low-light level video camera. It was possible to keep rat spinal motoneurones in culture for up to 5 weeks when cocultured with myotubes and up to 7 days when cultured over glia monolayers. In contrast, the survival of motoneurones on fibroblasts was poor. Myotubes gave the best conditions to neurite growth and development of motoneurones in vitro. Glial cells were also a permissive environment for motoneurone development, although with a reduced rate of growth, for only a few days, and mainly of proximal dendrites. The results of this study showed that motoneurones in culture can survive in the absence of muscle, and that glia cells are a permissive environment for a time that in the embryo goes well into the period of natural cell death, and that the interaction with non-neuronal cells affects different types of neurite growth. These results are discussed in terms of possible influences that cell-cell contact, and cell adhesion molecules, may exert on the development of spinal motoneurones

Usability of an Educational Intervention to Overcome Therapeutic Inertia in Multiple Sclerosis Care

Background: Educational interventions are needed to overcome knowledge-to-action gaps in clinical care. We previously tested the feasibility and potential efficacy of an educational intervention that facilitates treatment decisions in multiple sclerosis care. A demonstration of the usability of such an intervention is crucial prior to demonstration of efficacy in a large trial.Objectives: To evaluate the usability of a novel, pilot-tested intervention aimed at neurologists to improve therapeutic decisions in multiple sclerosis (MS) care.Methods: We surveyed 50 neurologists from Chile, Argentina, and Canada randomized to an educational intervention arm of a pilot feasibility study using the System Usability Score (SUS) to assess the usability of a traffic light system (TLS)-based educational intervention. The TLS facilitates therapeutic decisions, allowing participants to easily recognize high-risk scenarios requiring treatment escalation. The SUS is a validated 10-item questionnaire with five response options. The primary outcome was the average and 95% confidence interval (CI) of the SUS score. Values above 68 are considered highly usable.Results: Of 50 neurologists invited to be part of the study, all completed the SUS scale and the study. For the primary outcome, the average usability score was 74.7 (95%CI 70.1–79.2). There was one outlier with a score of 35. The usability score excluding the outlier was 76.8 (95%CI 72.7–80.8). Multivariate analysis revealed no association between participants' characteristics and the SUS score.Conclusions: Our educational intervention has shown high usability among neurologists. The next step is to evaluate the effectiveness of this educational intervention in facilitating treatment decisions for the management of multiple sclerosis in a large trial