Rapid Dissemination of SIV Follows Multisite Entry after Rectal Inoculation

Receptive ano-rectal intercourse is a major cause of HIV infection in men having sex with men and in heterosexuals. Current knowledge of the mechanisms of entry and dissemination during HIV rectal transmission is scarce and does not allow the development of preventive strategies. We investigated the early steps of rectal infection in rhesus macaques inoculated with the pathogenic isolate SIVmac251 and necropsied four hours to nine days later. All macaques were positive for SIV. Control macaques inoculated with heat-inactivated virus were consistently negative for SIV. SIV DNA was detected in the rectum as early as four hours post infection by nested PCR for gag in many laser-microdissected samples of lymphoid aggregates and lamina propria but never in follicle-associated epithelium. Scarce SIV antigen positive cells were observed by immunohistofluorescence in the rectum, among intraepithelial and lamina propria cells as well as in clusters in lymphoid aggregates, four hours post infection and onwards. These cells were T cells and non-T cells that were not epithelial cells, CD68+ macrophages, DC-SIGN+ cells or fascin+ dendritic cells. DC-SIGN+ cells carried infectious virus. Detection of Env singly spliced mRNA in the mucosa by nested RT-PCR indicated ongoing viral replication. Strikingly, four hours post infection colic lymph nodes were also infected in all macaques as either SIV DNA or infectious virus was recovered. Rapid SIV entry and dissemination is consistent with trans-epithelial transport. Virions appear to cross the follicle-associated epithelium, and also the digestive epithelium. Viral replication could however be more efficient in lymphoid aggregates. The initial sequence of events differs from both vaginal and oral infections, which implies that prevention strategies for rectal transmission will have to be specific. Microbicides will need to protect both digestive and follicle-associated epithelia. Vaccines will need to induce immunity in lymph nodes as well as in the rectum

Does quality management improve performance or vice versa? Evidence from the hotel industry

This paper has several aims: (a) to identify an empirical taxonomy of quality management (QM), (b) to assess whether more advanced QM hotels achieve better performance levels and (c) to analyse whether hotels with better performance levels have more advanced QM levels. This paper contributes to identify a taxonomy of QM in hotels showing the association between a particular level of QM and different performance dimensions. In addition, the paper sheds light on the possible selection effect in the hotel industry. The study finds that hotels with higher QM levels have better hotel guest satisfaction and employee satisfaction, efficiency and better business performance. It also shows that hotels with better performance levels develop QM to a greater extent. Accordingly, QM level is one factor among others that explain better performance levels in hotels. Also, good performance can facilitate the implementation of QM practices.This work has been carried out as part of the research project ECO2009-12231 funded by the Science and Innovation Ministry (Plan Nacional de I+D+i)