The publics of public health in Africa

How do we understand the public character of public health in contemporary Africa? What are the parameters of community engagement in health care delivery, medical research and disease control programmes? To what extent is public health in Africa a project led by African Governments? Through what political processes and deliberative practices can African publics influence the priorities of research in health sciences and interventions which aim in broad terms to improve the health of such publics? Drawing insight from empirical research conducted with African scientists, nurses, community members, clinical trialists and policy-makers, this special section examines the multiple ways in which the public comes into being around public health provisioning and investigation in sub-Saharan Africa, its role and political reach. Collectively, these papers show how contestation and negotiation around different ideas about who the public is and what being public means can lead to the emergence of conflicting understandings, with implications for who and what is seen to represent the public interest, and for the acceptance of research and other interventions

The Majority of MicroRNAs Detectable in Serum and Saliva Is Concentrated in Exosomes

There is an increasing interest in using microRNAs (miRNA) as biomarkers in autoimmune diseases. They are easily accessible in many body fluids but it is controversial if they are circulating freely or are encapsulated in microvesicles, particularly exosomes. We investigated if the majority of miRNas in serum and saliva are free-circulating or concentrated in exosomes. Exosomes were isolated by ultracentrifugation from fresh and frozen human serum and saliva. The amount of selected miRNAs extracted from the exosomal pellet and the exosome-depleted serum and saliva was compared by quantitative RT-PCR. Some miRNAs tested are ubiquitously expressed, others were previously reported as biomarkers. We included miRNAs previously reported to be free circulating and some thought to be exosome specific. The purity of exosome fraction was confirmed by electronmicroscopy and western blot. The concentration of miRNAs was consistently higher in the exosome pellet compared to the exosome-depleted supernatant. We obtained the same results using an equal volume or equal amount of total RNA as input of the RT-qPCR. The concentration of miRNA in whole, unfractionated serum, was between the exosomal pellet and the exosome-depleted supernatant. Selected miRNAs, which were detectable in exosomes, were undetectable in whole serum and the exosome-depleted supernantant. Exosome isolation improves the sensitivity of miRNA amplification from human biologic fluids. Exosomal miRNA should be the starting point for early biomarker studies to reduce the probability of false negative results involving low abundance miRNAs that may be missed by using unfractionated serum or saliva

Facts, power and global evidence: a new empire of truth

What are the epistemological and political contours of evidence today? This introduction to the Special Issue on Global Evidence lays out key shifts in the contemporary politics of knowledge and describes the collective contribution of the five papers as an articulation of what we describe as a ‘new empiricism’, exploring how earlier historical appeals to evidence to defend political power and decision-making both chime with and differ from those of the contemporary era. We outline some emerging empirical frontiers in the study of instruments of calculation, from the evolution of the randomised controlled trial (RCT) to the growing importance of big data, and explore how these methodological transformations intersect with the alleged crisis of expertise in the ‘post-truth’ era. In so doing, we suggest that the ambiguity of evidence can be a powerful tool in itself, and we relate this ambiguity to the ideological commitment and moral fervour that is elicited through appeals to, and the performance of, evaluation