Measurements of low oxygen tension in vitro and response of macrophages to levels applicable to peri- and postoperative treatment of traumatic brain injury

Established clinical guidelines for treatment of severe traumatic brain injury aim at maintaining intracranial and cerebral perfusion pressures. Recently, it has been shown that additional regulation of cerebral oxygen delivery helps to decrease patient mortality and leads to improved 6-month quality-of-life scores. However, eubaric oxygen-guided therapy is still controversial since it is well known that hyperoxia can cause unwanted secondary brain injury. Research studies are warranted to better understand the range of oxygen pressures that positively influence brain cell behavior. We perform such studies using a two-enzyme in vitro system that allows exposing tissue culture cells to various steady-state, or rapidly changing, oxygen pressures. Here, we present a mathematical model of the system and its validation by real-time monitoring of oxygen tensions. We additionally present preliminary evidence that human brain macrophages have a different oxygen tolerance compared to systemic macrophages and propose improvements to our in vitro system to make it applicable for data collection that aim at refining oxygen-guided therapy for patients with traumatic brain injury

A methodology for assessing rural livelihood strategies in West/Central Africa: lessons from the field

This paper critically evaluates and discusses some of the methodological practicalities of applying a combined participatory and small-scale survey approach to investigating rural livelihood strategies of people living in the humid forest zone of Southwest Cameroon, Southeast Nigeria and Southwest Ghana, with particular reference to assessing the economic importance of non-timber forest products. It describes the sampling methods used to select study zones, settlements and households as well as the participatory techniques and instruments used to differentiate households and gather information on rural incomes. Details of the successes and problems encountered during implementation are presented. The challenges faced by those conducting this study are also encountered by others carrying out comparable research. By sharing our experiences, we hope that the design of similar conservation and development-based research can be improved