SummaryContrary to previous studies, we found that Xenopus laevis tadpoles raised in normoxic water without access to air can routinely complete metamorphosis with lungs that are either severely stunted and uninflated or absent altogether. This is the first demonstration that lung development in a tetrapod can be inhibited by environmental factors and that a tetrapod that relies significantly on lung respiration under unstressed conditions can be raised to forego this function without adverse effects. This study compared lung development in untreated, air-deprived (AD) and air-restored (AR) tadpoles and frogs using whole mounts, histology, BrdU labeling of cell division and antibody staining of smooth muscle actin. We also examined the relationship of swimming and breathing behaviors to lung recovery in AR animals. Inhibition and recovery of lung development occurred at the stage of lung inflation. Lung recovery in AR tadpoles occurred at a predictable and rapid rate and correlated with changes in swimming and breathing behavior. It thus presents a new experimental model for investigating the role of mechanical forces in lung development. Lung recovery in AR frogs was unpredictable and did not correlate with behavioral changes. Its low frequency of occurrence could be attributed to developmental, physical and behavioral changes, the effects of which increase with size and age. Plasticity of lung inflation at tadpole stages and loss of plasticity at postmetamorphic stages offer new insights into the role of developmental plasticity in amphibian lung loss and life history evolution.

Change in level of consciousness is associated with sICH among patients undergoing emergent brain imaging after receiving tPA. In this group of patients, preparation of tPA reversal agents while awaiting brain imaging may reduce reversal times. Future studies are needed to study the cost-effectiveness of this approach.

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Introduction: Although studies have examined emergent CTAs of the head and neck in patients seen by neurologists who are suspected of having a large vessel occlusion, the utility and accuracy of CTA for patients called as a ‘code stroke’ by any healthcare provider has not been evaluated. Methods: At our institution, imaging for all Code Stroke patients includes non-contrast CT of the brain as well as CTA of the neck and brain, regardless of severity. This imaging is often performed prior to detailed neurology evaluation. We queried our radiology department report database for all studies labelled ‘CTA ELVO’, an imaging order code which is specific for Code Stroke. We then cross-referenced this list with our prospectively acquired ischemic stroke registry, which consists of all patients discharged with a diagnosis of acute ischemic stroke. Results: Between January and August 2017, 1265 CTA ELVOs were performed. Average age was 66.3 years, and 52.4% were female. Of all CTA ELVOs, 144 were performed on inpatients (11.3%) and neuroradiologists read 149 studies (11.8%). Critical findings on vessel imaging were present in 165 studies (13%); of these 118 patients were ultimately diagnosed with acute ischemic stroke. Studies with critical findings involved older patients (73.7 years, p<0.001) and were less likely to be performed on inpatients (29 studies, p=0.012) but were no different in number of females (55%, p=0.51) or whether read by a neuroradiologist (23 studies, p=0.36). Critical findings included acute intracranial large vessel occlusion involving the middle cerebral artery, intracranial internal carotid artery (ICA), or basilar artery (87 studies); critical cervical ICA stenosis, acute cervical ICA occlusion, or acute dissection (42 studies); M2 occlusion (32 studies); critical intracranial stenosis (7 studies) and vascular malformation such as aneurysm or arteriovenous malformation (6 studies). Conclusion: The yield of non-invasive vessel imaging in patients called as a code stroke in detecting critical findings is high, revealing abnormalities in approximately one in eight patients. Patients presenting with acute neurologic symptoms should receive vessel imaging as part of the initial workup for suspected stroke.