In the retina of warm-blooded vertebrates, photoreceptors are specified many days before the onset of synaptogenesis and the expression of photopigments. The factors that regulate the maturation of photoreceptors in the developing retina remain unknown. We report here that photoreceptors transiently express LIM-domain transcription factors during the development of the chicken retina. We examined the differentiation of photoreceptors through the normal course of embryonic development and at the far periphery of the postnatal retina, where the differentiation of photoreceptors is slowed and persists across a spatial gradient. In the embryonic retina, we find visinin-positive photoreceptors that transiently express Islet2 and Lim3 starting at E8 and ending around E15, but persisting in far peripheral regions of the retina through the first 2 weeks of postnatal development. During early stages of photoreceptor maturation, there is coincident and transient expression of the LIM-domain factors with axonin1, a cell surface glycoprotein that is a member of the immunoglobulin super family. Coincident with the down-regulation of Islet2 and Lim3, we find the up-regulation of calbindin, red/green opsin, rhodopsin and a synaptic marker in the OPL (dystrophin). In the periphery of the postnatal retina, photoreceptors that express Islet2, Lim3 and axonin1 do not overlap with photoreceptors that express calbindin, red/geen opsin, rhodopsin, and dystrophin. We propose that Islet2 and Lim3 may promote the expression of genes that are involved in the early stages of differentiation, but may suppress the expression of genes that are required in the mature photoreceptors.

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Objective: To determine the effects of rapid sequence intubation in patients with severe head injury performed by paramedics on a helicopter emergency medical service. Methods: The patient care records for patients with severe head injury who underwent rapid sequence intubation between November 1999 and February 2002 (inclusive) were examined. Data were extracted on the demographics of the patients, as well as the physiological changes before and after rapid sequence intubation. Results: There were 122 patients with severe head injury evaluated at the scene during the study period. Rapid sequence intubation was attempted in 110 patients and was successful in 107 (97%). Intubation was associated with improvements in systolic blood pressure, oxygen saturation and end‐tidal carbon dioxide levels, compared with baseline levels. Conclusion: Rapid sequence intubation in patients with severe head injury may be safely undertaken by helicopter‐based ambulance paramedics and is associated with improvements in oxygenation, ventilation and blood pressure. Further studies of this skill undertaken by road‐based paramedics are warranted.

Rationale Mobile stroke units (MSUs) are increasingly being implemented to provide acute stroke care in the prehospital environment, but a comprehensive implementation evaluation has not been undertaken. Aim To identify successes and challenges in the pre‐ and initial operations of the first Australian MSU service from an interdisciplinary perspective. Methods Process evaluation of the Melbourne MSU with a mixed‐methods design. Purposive sampling targeted key stakeholder groups. Online surveys (administered June–September 2019) and semistructured interviews (October–November 2019) explored experiences. Directed content analysis (raters' agreement 85%) and thematic analysis results are presented using the Interactive Sociotechnical Analysis framework. Results Participants representing executive/program operations, MSU clinicians and hospital‐based clinicians completed 135 surveys and 38 interviews. Results converged, with major themes addressing successes and challenges: stakeholders, vehicle, knowledge, training/education, communication, work processes and working relationships. Conclusions Successes and challenges of establishing a new MSU service extend beyond technical, to include operational and social aspects across prehospital and hospital environments.