West Nile virus (WNV): generalities and implications for blood transfusion]

West Nile virus (WNV) is an arbovirus (genus Flavivirus, Family Flaviviridae, transmitted to humans by mosquito bite. In most cases (80%), human infection remains asymptomatic. Severe central nervous system complications (encephalitis and meningoencephalitis) are rare. In the Old World, the virus circulation has been demonstrated in Asia, Australia, Africa, Middle East and Europe. Several outbreaks in humans have been described. Following its introduction into North America in 1999, WN virus has been responsible of a large number of human cases in USA and Canada. For the first time, viral transmission by blood products was clearly demonstrated in USA in 2002. In France, the presence of virus has been reported in the Southeastern departments since 1962. In 2003, the occurrence of humans cases at specific geographical foci urged the French National Blood Agency (etablissement francais du sang) to take preventive measures for evaluating the virus transmission risks.     

Application of molecular biology to blood transfusion safety: the nucleic acid testing]

Nucleic Acid Testing (NAT) for HIV-1 and HCV has been introduced in France and became mandatory for all homologous blood donations since July 1st 2001 in addition to serology screening. Previously, a feasibility study led to the selection of 2 technologies : a TMA based assay (Chiron) uses the Procleix HIV-/HCV assay on pools of 8 samples and a PCR based assay from BioMérieux-Roche which is a combination of an RNA extraction system (NucliSens, BioMérieux) with a fully automated system for nucleic acid amplification and detection (Cobas Amplicor, Roche). This system uses the Cobas Ampliscreen HCV test v.2.0 and the The Cobas Ampliscreen HIV test v1.5, on 24 sample pools. Pooling was required because single-donation testing is not yet feasible, as a result of the limitations in automation available for all current NAT technologies. The two technologies were easily implemented and showed nearly the same detection limit for HCV RNA and HIV-1 RNA. During a one-year period, from July 1st 2001 to June 30, 2002, out of the 2.5 million donations tested, the NAT yield resulted in one HIV-1 RNA positive-antibody negative donation and one HCV RNA positive-antibody negative donation. Two HIV NAT positive-antibody negative donations were missed by minipool NAT because a very low viral load. Moreover, the NAT implementation did not impact on blood component availability, including platelet concentrates.     

Somatic stem cells and the origin of cancer

Most human cancers derive from a single cell targeted by genetic and epigenetic alterations that initiate malignant transformation. Progressively, these early cancer cells give rise to different generations of daughter cells that accumulate additional mutations, acting in concert to drive the full neoplastic phenotype^1,2. As we have currently deciphered many of the gene pathways disrupted in cancer, our knowledge about the nature of the normal cells susceptible to transformation upon mutation has remained more elusive. Adult stem cells are those that show long-term replicative potential, together with the capacities of self-renewal and multi-lineage differentiation. These stem cell properties are tightly regulated in normal development, yet their alteration may be a critical issue for tumorigenesis. This concept has arisen from the striking degree of similarity noted between somatic stem cells and cancer cells, including the fundamental abilities to self-renew and differentiate. Given these shared attributes, it has been proposed that cancers are caused by transforming mutations occurring in tissue-specific stem cells^3–9. This hypothesis has been functionally supported by the observation that among all cancer cells within a particular tumor, only a minute cell fraction has the exclusive potential to regenerate the entire tumor cell population^3,10–13; these cells with stem-like properties have been termedcancer stem cells. Cancer stem cells can originate from mutation in normal somatic stem cells that deregulate their physiological programs. Alternatively, mutations may target more committed progenitor cells or even mature cells, which become reprogrammed to acquire stem-like functions^14,15 In any case, mutated genes should promote expansion of stem/progenitor cells, thus increasing their predisposition to cancer development by expanding self-renewal and pluripotency over their normal tendency towards relative quiescency and proper differentiation. Supported by an unrestricted educational grant from Astrazeneca.     

¿Cómo abordar la dimensión colectiva de la salud de las personas? Informe SESPAS 2012

The health of the population largely depends on environmental factors, raising the issue of what the role of health professionals, particularly those in public health and primary care, should be in the planning of objectives and actions for improvement. The present article proposes a trajectory, starting with knowledge of the community's strong points in health and its needs, and ending with taking action. This trajectory requires discussion on how information can be transformed into action. We analyze the current situation and its strengths and weaknesses, and make proposals for the entire process: from information to action. Information is more than just the available data gathered from different sources; it is also knowledge of those who belong to the community or are very close to it. This perspective should include both health deficits and health assets. This information should be used not only by health professionals, but by all those in a position to influence the determinants of health. Finally, when considering the actions required to improve the health of a community, we emphasize the benefits of health promotion, in the genuine sense of the term, by reflecting on effectiveness and efficiency. The question of whether the failure of an intervention to improve health is due to the futility of the action, or to be action being undertaken in an inefficient way, is discussed.     

Withholding Preoperative Antibiotic Prophylaxis in Knee Prosthesis Revision: A Retrospective Analysis on Culture Results and Risk of Infection

Background

A significant amount of patients undergoing revision surgery of a prosthetic joint turn out to have an infection. Withholding preoperative antibiotic prophylaxis in these patients to optimize culture yield during revision surgery remains a matter of debate. The aim of our study was to determine (1) the rate of positive intraoperative cultures with or without preoperative antibiotic prophylaxis and (2) the incidence of a prosthetic joint infection (PJI) during the follow-up in the 2 groups.