Anesthesia and blood sampling of wild big brown bats (eptesicus fuscus) with an assessment of impacts on survival.

We anesthetized and blood sampled wild big brown bats (Eptesicus fuscus) in Fort Collins, Colorado (USA) in 2001 and 2002 and assessed effects on survival. Inhalant anesthesia was delivered into a specially designed restraint and inhalation capsule that minimized handling and bite exposures. Bats were immobilized an average of 9.1+/-5.1 (SD) min (range 1-71, n=876); blood sample volumes averaged 58+/-12 microl (range 13-126, n=718). We randomly selected control (subject to multiple procedures before release) and treatment (control procedures plus inhalant anesthesia and 1% of body weight blood sampling) groups in 2002 to assess treatment effects on daily survival over a 14-day period for adult female and volant juvenile bats captured at maternity roosts in buildings. We monitored survival after release using passive integrated transponder tag detection hoops placed at openings to selected roosts. Annual return rates of bats sampled in 2001 were used to assess long-term outcomes. Comparison of 14-day maximum-likelihood daily survival estimates from control (86 adult females, 92 volant juveniles) and treated bats (187 adult females, 87 volant juveniles) indicated no adverse effect from anesthesia and blood sampling (juveniles: chi2=22.22, df=27, P>0.05; adults: chi2=9.72, df=18, P>0.05). One-year return rates were similar among adult female controls (81%, n=72, 95% confidence interval [CI]=70-91%), females treated once (82%, n=276, 95% CI=81-84%), and females treated twice (84%, n=50, 95% CI=74-94%). Lack of an effect was also noted in 1-yr return rates of juvenile female controls (55%, n=29, 95% CI=37-73%), juveniles treated once (66%, n=113, 95% CI=58-75%), and juveniles treated twice (71%, n=17, 95% CI=49-92%). These data suggest that anesthesia and blood sampling for health monitoring did not measurably affect survival of adult female and volant juvenile big brown bats.

Chemical anoxia of tubular cells induces activation of c-Src and its translocation to the zonula adherens.

Cyanide (CN)-induced chemical anoxia of cultured mouse proximal tubular (MPT) cells increased the kinase activity of c-Src by approximately threefold. 4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), a specific inhibitor of c-Src, prevented Src activation. CN also increased the permeability of MPT cell monolayers, an event ameliorated by PP2. During CN treatment, the proteins of the zonula adherens (ZA; E-cadherin and the catenins) disappeared from their normal location at cell-cell borders and appeared within the cytosol. CN also resulted in the appearance of c-Src at cell-cell borders. PP2 prevented these CN-induced alterations in the distribution of ZA proteins and c-Src. CN also increased the association of c-Src with beta-catenin and p120 and induced a substantial increase in tyrosine phosphorylation of both catenins. PP2 prevented the CN-induced phosphorylation of these catenins. In summary, we show that CN-induced chemical anoxia activates c-Src and induces its translocation to cell-cell junctions where it binds to and phosphorylates beta-catenin and p120. Our findings suggest that these events contribute to the loss of the epithelial barrier function associated with chemical anoxia.

ATP depletion of tubular cells causes dissociation of the zonula adherens and nuclear translocation of beta-catenin and LEF-1.

This study examined the events associated with the reversible disruption of the structural and functional integrity of the zonula occludens (ZA) induced by ATP depletion of renal tubular cells. It shows that loss of the ZA after ATP depletion is associated with the withdrawal of E-cadherin, alpha-catenin, and beta-catenin, probably as intact cadherin-catenin complexes from the basolateral membrane of tubular cells. The relative amounts of all three proteins increased in the Triton X-100-insoluble fraction of cell lysates and decreased in the Triton X-100-soluble pool. These changes were reversed with repletion of cell ATP. It is additionally shown that ATP depletion induces nuclear translocation of beta-catenin and T cell factor (TCF)/lymphoid enhancer factor-1 (LEF-1), a transcriptional factor with which beta-catenin associates. The redistribution of the ZA proteins as intact E-cadherin-catenin complexes from the plasma membrane facilitates the rapid recovery of the ZA after sublethal ischemic injury. The translocation of beta-catenin and TCF/LEF-1 to the nucleus indicates that ATP depletion may activate the wnt/wingless signal transduction pathway. Thus, entirely novel evidence is provided that both of the known roles of beta-catenin, as a structural part of the ZA and as a component of the wnt/wingless pathway, play a role after sublethal ischemic injury to tubular cells. It is also speculated that the nuclear translocation of beta-catenin and TCF/LEF-1 modulates gene expression after ischemic injury and may contribute to events necessary for renal regeneration and repair after ischemic injury.