Debating the Desirability of New Biomedical Technologies: Lessons from the Introduction of Breast Cancer Screening in the Netherlands

Health technology assessment (HTA) was developed in the 1970s and 1980s to facilitate decision making on the desirability of new biomedical technologies. Since then, many of the standard tools and methods of HTA have been criticized for their implicit normativity. At the same time research into the character of technology in practice has motivated philosophers, sociologists and anthropologists to criticize the traditional view of technology as a neutral instrument designed to perform a specific function. Such research suggests that the tools and methods of more traditional forms of HTA are often inspired by an ‘instrumentalist’ conception of technology that does not fit the way technology actually works. This paper explores this hypothesis for a specific case: the assessments and deliberations leading to the introduction of breast cancer screening in the Netherlands. After reconstructing this history of HTA ‘in the making’ the stepwise model of HTA that emerged during the process is discussed. This model was rooted indeed in an instrumentalist conception of technology. However, a more detailed reconstruction of several episodes from this history reveals how the actors already experienced the inadequacy of some of the instrumentalist presuppositions. The historical case thus shows how an instrumentalist conception of technology may result in implicit normative effects. The paper concludes that an instrumentalist view of technology is not a good starting point for HTA and briefly suggests how the fit between HTA methods and the actual character of technology in practice might be improved

Direct Stimulation of Adult Neural Stem/Progenitor Cells In Vitro and Neurogenesis In Vivo by Salvianolic Acid B

Background: Small molecules have been shown to modulate the neurogenesis processes. In search for new therapeutic drugs, the herbs used in traditional medicines for neurogenesis are promising candidates. Methodology and Principal Findings: We selected a total of 45 natural compounds from Traditional Chinese herbal medicines which are extensively used in China to treat stroke clinically, and tested their proliferation-inducing activities on neural stem/progenitor cells (NSPCs). The screening results showed that salvianolic acid B (Sal B) displayed marked effects on the induction of proliferation of NSPCs. We further demonstrated that Sal B promoted NSPCs proliferation in dose- and time-dependent manners. To explore the molecular mechanism, PI3K/Akt, MEK/ERK and Notch signaling pathways were investigated. Cell proliferation assay demonstrated that Ly294002 (PI3K/Akt inhibitor), but neither U0126 (ERK inhibitor) nor DAPT (Notch inhibitor) inhibited the Sal B-induced proliferation of cells. Western Blotting results showed that stimulation of NSPCs with Sal B enhanced the phosphorylation of Akt, and Ly294002 abolished this effect, confirming the role of Akt in Sal B mediated proliferation of NSPCs. Rats exposed to transient cerebral ischemia were treated for 4 weeks with Sal B from the 7th day after stroke. BrdU incorporation assay results showed that exposure Sal B could maintain the proliferation of NSPCs after cerebral ischemia. Morris water maze test showed that delayed post-ischemic treatment with Sal B improved cognitive impairment after stroke in rats

Airborne measurements in a stable boundary layer over the Larsen Ice Shelf, Antarctica

We present aircraft measurements of boundary-layer structure and surface turbulent fluxes from a flight over the Larsen Ice Shelf, Antarctica. Warm advection, associated with föhn flow, led to the formation of a stable boundary layer over the ice shelf, with a well-defined low-level jet at the top of the surface inversion. The strong shear associated with the jet kept the gradient Richardson number small and maintained a turbulent boundary layer over a depth of at least 600 m. The net surface energy balance amounted to 52 Wm−2, equivalent to a melt rate of 13 mm water per day, with net radiation (48 Wm−2) making the largest contribution to melt. The contribution from the sensible heat flux (13 Wm−2) was largely balanced by an upwards latent heat flux (−9 Wm−2). These measurements provide insight into the processes that control surface melt rates in an area that has experienced recent rapid warming and deglaciation