Archaeological approaches to RNA virus evolution

Studies with RNA enzymes (ribozymes) and protein enzymes have identified certain structural elements that are present in some cellular mRNAs and viral RNAs. These elements do not share a primary structure and, thus, are not phylogenetically related. However, they have common (secondary/tertiary) structural folds that, according to some lines of evidence, may have an ancient and common origin. The term 'mRNA archaeology' has been coined to refer to the search for such structural/functional relics that may be informative of early evolutionary developments in the cellular and viral worlds and have lasted to the present day. Such identified RNA elements may have developed as biological signals with structural and functional relevance (as if they were buried objects with archaeological value), and coexist with the standard linear information of nucleic acid molecules that is translated into proteins. However, there is a key difference between the methods that extract information from either the primary structure of mRNA or the signals provided by secondary and tertiary structures. The former (sequence comparison and phylogenetic analysis) requires strict continuity of the material vehicle of information during evolution, whereas the archaeological method does not require such continuity. The tools of RNA archaeology (including the use of ribozymes and enzymes to investigate the reactivity of the RNA elements) establish links between the concepts of communication and language theories that have not been incorporated into knowledge of virology, as well as experimental studies on the search for functionally relevant RNA structures.

Vulnerability as a palimpsest: Practices and public policy in a Mexican hospital setting

Vulnerability is a concept associated with the effects of social inequities to access health care services. On a hospital level, vulnerable populations must be identified and favored over others. The aims of this study were the analysis of the conceptions and practices of social workers regarding vulnerable patients, and the identification of theoretical elements of vulnerability given by academics. Hospital ethnography and a focus group were implemented. Social workers related vulnerability to the social needs of each patient; however, they state that they have dilemmas to identify a person in a vulnerable condition; these dilemmas are related to social differences and deservingness. Academics indicated that the vulnerability should refer to the lack of access to health services offered by the institution. Academics agree with social workers regarding the importance of considering the overlapped social and individual circumstances in each patient to recognize their vulnerable condition, regardless of belonging to any of the pre-established vulnerable groups. Finally, taking into account the way of conceptualizing vulnerability and how public policy on the identification of vulnerable patients in the hospital has been implemented, these two elements are explained using the palimpsest model, which is a figure of thought that can be applied to analyze the sociocultural significance of this complex issue, as well as other social dynamics.