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Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutation of PKD1 and PKD2 that encode polycystin-1 and polycystin-2. Polycystin-1 is tyrosine phosphorylated and modulates multiple signaling pathways including AP-1, and the identity of the phosphatases regulating polycystin-1 are previously uncharacterized. Here we identify members of the LAR protein tyrosine phosphatase (RPTP) superfamily as members of the polycystin-1complex mediated through extra- and intracellular interactions. The first extracellular PKD1 domain of polycystin-1 interacts with the first Ig domain of RPTPσ, while the polycystin-1 C-terminus of polycystin-1 interacts with the regulatory D2 phosphatase domain of RPTPγ. Additional homo- and heterotypic interactions between RPTPs recruit RPTPδ. The multimeric polycystin protein complex is found localised in cilia. RPTPσ and RPTPδ are also part of a polycystin-1/E-cadherin complex known to be important for early events in adherens junction stabilisation. The interaction between polycystin-1 and RPTPγ is disrupted in ADPKD cells, while RPTPσ and RPTPδ remain closely associated with E-cadherin, largely in an intracellular location. The polycystin-1 C-terminus is an in vitro substrate of RPTPγ, which dephosphorylates the c-Src phosphorylated Y4237 residue and activates AP1-mediated transcription. The data identify RPTPs as novel interacting partners of the polycystins both in cilia and at adhesion complexes and demonstrate RPTPγ phosphatase activity is central to the molecular mechanisms governing polycystin-dependent signaling. This article is part of a Special Issue entitled: Polycystic Kidney Disease., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Using resource selection functions, we examined habitat selection patterns of barren-ground grizzly bears (Ursus arctos) in the central Canadian Arctic among and within home ranges. There was no difference between the sexes with regard to habitat selection patterns at the home range level (Wilks' λ, approx. F 11,11 =1.27, P=0.37). Bear home ranges contain more esker habitat, tussock/hummock successional tundra, lichen veneer, birch seep, and tall shrub riparian areas relative to the proportional availability of habitats in the study area. We observed differences in habitat selection within home ranges among levels of sex/reproductive status (Wilks' λ, approx. F 20,412 =3.32, P<0.001) and by season (Wilks' λ, approx. F 30,605 =2.71, P<0.001). Eskers and tall shrub riparian zones were the habitats most preferred by bears throughout the year. Tussock/hummock successional tundra was also favored by males at varying times during the year and lichen veneers were favored in spring and autumn by most bears. Females with cubs tended to avoid the highest ranked habitat for males throughout the year. This pattern of habitat selection was not observed for females without accompanying young. Results of this study underline the importance of scale dependence in habitat selection. Failure to view habitat selection as a hierarchical process may result in a narrow and possibly misleading notion of habitat selection patterns.

Currently there is little information regarding the immunologic mechanisms responsible for large local reaction (LLR) after Hymenoptera stings. To investigate this question, we measured in vitro lymphocyte proliferation and delayed skin reactivity to venom antigens in 10 subjects with LLR (six with LLR only and four with LLR and systemic reactions), seven subjects with systemic reactions, and eight nonallergic controls. The lymphocyte response to venoms in the LLR group was greater than that in either the systemic reactor group (p less than 0.05) or the control group (p less than 0.001). In contrast, lymphoproliferative responses to Candida albicans, streptokinase-streptodornase, and phytohemagglutinin were comparable in the three groups. Forty percent of the LLR group had positive delayed skin tests to venom antigens, and none of the patients in the systemic reactor group had such responses. These findings suggest that cellular immune mechanisms play a role in the pathogenesis of LLR after Hymenoptera stings.

Hospitals with American Society of Hospital Pharmacists accredited residencies were surveyed to assess the state of the art for adverse drug reaction (ADR) reporting. A majority of hospitals used a concurrent ADR reporting mechanism. Only one-fourth of hospitals assessed the causal relationship between the drug and the ADR, whereas the majority assessed the severity of the ADR. Fifty-eight per cent of hospitals received fewer than seven ADR reports in a 6-month period. Antiinfective agents and central nervous system drugs were most frequently cited as causing ADRs. Various corrective action has been taken to reduce ADRs, including changing drug administration procedures, promoting awareness of ADRs, patient teaching, and drug monitoring.