No abstract

Non-steroidal anti-inflammatory drugs (NSAIDs) contribute to gastrointestinal ulcer formation by inhibiting epithelial cell migration and mucosal restitution; however, the drug-affected signaling pathways are poorly defined. We investigated whether NSAID inhibition of intestinal epithelial migration is associated with depletion of intracellular polyamines, depolarization of membrane potential (E m ) and altered surface expression of K + channels. Epithelial cell migration in response to the wounding of confluent IEC-6 and IEC-Cdx2 monolayers was reduced by indomethacin (100 μM), phenylbutazone (100 μM) and NS-398 (100 μM) but not by SC-560 (1 μM). NSAIDinhibition of intestinal cell migration was not associated with depletion of intracellular polyamines. Treatment of IEC-6 and IEC-Cdx2 cells with indomethacin, phenylbutazone and NS-398 induced significant depolarization of E m , whereas treatment with SC-560 had no effect on E m . The E m of IEC-Cdx2 cells was: −38.5±1.8 mV under control conditions; −35.9±1.6 mV after treatment with SC-560; −18.8±1.2 mV after treatment with indomethacin; and −23.7±1.4 mV after treatment with NS-398. Whereas SC-560 had no significant effects on the total cellular expression of K v 1.4 channel protein, indomethacin and NS-398 decreased not only the total cellular expression of K v 1.4, but also the cell surface expression of both K v 1.4 and K v 1.6 channel subunits in IEC-Cdx2. Both K v 1.4 and K v 1.6 channel proteins were immunoprecipitated by K v 1.4 antibody from IEC-Cdx2 lysates, indicating that these subunits co-assemble to form heteromeric K v channels. These results suggest that NSAID inhibition of epithelial cell migration is independent of polyamine-depletion, and is associated with depolarization of E m and decreased surface expression of heteromeric K v 1 channels.

No abstract

To explore geographic and host-taxonomic patterns of hantaviruses in Paraguay, we established sampling sites in the Mbaracayú Biosphere Reserve. We detected Jaborá virus and Itapúa37/Juquitiba–related virus in locations ≈20 m apart in different years, which suggested sympatry of 2 distinct hantaviruses.

Hantaviruses may cause serious disease when transmitted to humans by their rodent hosts. Since their emergence in the Americas in 1993, there have been extensive efforts to understand the role of environmental factors on the presence of these viruses in their host rodent populations. HPS outbreaks have been linked to precipitation, but climatic factors alone have not been sufficient to predict the spatial-temporal dynamics of the environment-reservoir-virus system. Using a series of mark-recapture sampling sites located at the Mbaracayú Biosphere Reserve, an Atlantic Forest site in eastern Paraguay, we investigated the hypothesis that microhabitat might also influence the prevalence of Jaborá hantavirus within populations of its reservoir species, Akodon montensis. Seven trapping sessions were conducted during 2005-2006 at four sites chosen to capture variable microhabitat conditions within the study site. Analysis of microhabitat preferences showed that A. montensis preferred areas with little forest overstory and denser vegetation cover on and near the ground. Moreover, there was a significant difference in the microhabitat occupied by antibody-positive vs antibody-negative rodents, indicating that microhabitats with greater overstory cover may promote transmission and maintenance of hantavirus in A. montensis.