Metamorphosis of Subarachnoid Hemorrhage Research: from Delayed Vasospasm to Early Brain Injury

Delayed vasospasm that develops 3–7 days after aneurysmal subarachnoid hemorrhage (SAH) has traditionally been considered the most important determinant of delayed ischemic injury and poor outcome. Consequently, most therapies against delayed ischemic injury are directed towards reducing the incidence of vasospasm. The clinical trials based on this strategy, however, have so far claimed limited success; the incidence of vasospasm is reduced without reduction in delayed ischemic injury or improvement in the long-term outcome. This fact has shifted research interest to the early brain injury (first 72 h) evoked by SAH. In recent years, several pathological mechanisms that activate within minutes after the initial bleed and lead to early brain injury are identified. In addition, it is found that many of these mechanisms evolve with time and participate in the pathogenesis of delayed ischemic injury and poor outcome. Therefore, a therapy or therapies focused on these early mechanisms may not only prevent the early brain injury but may also help reduce the intensity of later developing neurological complications. This manuscript reviews the pathological mechanisms of early brain injury after SAH and summarizes the status of current therapies

Models of innovation: Why models of innovation are models, or what work is being done in calling them models?

Models abound in the literature on innovation. They are continuously being invented and succeed one after the other. At the same time, these models are regularly criticized. This article looks at models of innovation and conducts a conceptual analysis of models. To the producers and users of models of innovation, a model has at least five different meanings: conceptualization, narrative, figure, tool, and perspective. This article suggests that the term ‘model’ has both a scientific and a rhetorical function. A ‘model’ is a symbol of scientificity and travels easily between scholars and between the latter and policy-makers. Calling a conceptualization or narrative or tool ‘model’ facilitates its propagation