Phylogenetic risk assessment is robust for forecasting the impact of European insects on North American conifers.

Some introduced species cause severe damage, although the majority have little impact. Robust predictions of which species are most likely to cause substantial impacts could focus efforts to mitigate those impacts or prevent certain invasions entirely. Introduced herbivorous insects can reduce crop yield, fundamentally alter natural and managed forest ecosystems, and are unique among invasive species in that they require certain host plants to succeed. Recent studies have demonstrated that understanding the evolutionary history of introduced herbivores and their host plants can provide robust predictions of impact. Specifically, divergence times between hosts in the native and introduced ranges of a nonnative insect can be used to predict the potential impact of the insect should it establish in a novel ecosystem. However, divergence time estimates vary among published phylogenetic datasets, making it crucial to understand if and how the choice of phylogeny affects prediction of impact. Here, we tested the robustness of impact prediction to variation in host phylogeny by using insects that feed on conifers and predicting the likelihood of high impact using four different published phylogenies. Our analyses ranked 62 insects that are not established in North America and 47 North American conifer species according to overall risk and vulnerability, respectively. We found that results were robust to the choice of phylogeny. Although published vascular plant phylogenies continue to be refined, our analysis indicates that those differences are not substantial enough to alter the predictions of invader impact. Our results can assist in focusing biosecurity programs for conifer pests and can be more generally applied to nonnative insects and their potential hosts by prioritizing surveillance for those insects most likely to be damaging invaders.

Can we use dilution-titration studies to identify clinically relevant HLA antibody specificities?

These data suggest the presence of virtual crossmatch positive, low titer donor specific anti-human leukocyte antigen antibody (DSA) positive sera does not guarantee that real-time crossmatches will be positive. DSA that are present at an undiluted concentration but absent at a 1:8 or 1:16 dilution may not have to be considered unacceptable. This would allow potential recipients wider access to donor organs by reducing the number of listed unacceptable antigens. It also calls into question the use of virtual crossmatching, which may be disenfranchising minorities. Finally, evaluation of antibody concentration by dilution or titer may be clinically more useful than mean fluorescence intensity.

The crossmatch may still be the most clinically relevant histocompatibility test performed.

We evaluated patient sera for flow PRA, FCXM, and end-point donor-antigen titer, and we correlated the results with graft survival. You cannot accurately predict a positive or negative FCXM result-not even when the sera have donor-specific antigens-unless you actually perform a crossmatch. Using fluorescence intensity as a surrogate for antibody concentration does not correlate quantitatively with the occurrence of a positive or negative crossmatch. Therefore, it is imperative to give each recipient a chance at being offered a donor organ by performance of a real-time crossmatch and not rely on a virtual evaluation.

ENaC proteins are required for NGF-induced neurite growth.

Neurite growth is required for nervous system development and repair. Multiple signals, including neurotrophic factors and intact mechanosensing mechanisms, interact to regulate neurite growth. Degenerin/epithelial Na(+) channel (DEG/ENaC) proteins have been identified as putative mechanosensors in sensory neurons. Recently, others have shown that the neurotrophic factor NGF stimulates expression of acid-sensing ion channel molecules, which are members of the DEG/ENaC family. However, it is unknown whether NGF regulates ENaC expression or whether ENaC expression is required for neurite formation. Therefore, the aims of the present study were to determine whether ENaC expression is 1) regulated by NGF and 2) required for NGF-induced neurite growth in pheochromocytoma PC-12 cells. We found NGF-induced expression of beta- and gamma-subunits of ENaC, but not alpha-ENaC. Tyrosine kinase A (TrkA) receptor blockade abolished NGF-induced beta- and gamma-ENaC expression and neurite formation. NGF-induced neurite formation was inhibited by disruption of ENaC expression using 1) pharmacological blockade with benzamil, a specific ENaC inhibitor; 2) small interfering RNA; and 3) dominant-negative ENaC molecules. These data indicate NGF-TrkA regulation of ENaC expression may be required for neurite growth and may suggest a novel role for DEG/ENaC proteins in neuronal remodeling and differentiation.