Erythropoietin protects against diabetes through direct effects on pancreatic β cells

In mouse models of type 1 and type 2 diabetes, administration of human erythropoietin protects against disease by acting directly on pancreatic β cells

Diverse and Active Roles for Adipocytes During Mammary Gland Growth and Function

The mammary gland is unique in its requirement to develop in close association with a depot of adipose tissue that is commonly referred to as the mammary fat pad. As discussed throughout this issue, the mammary fat pad represents a complex stromal microenvironment that includes a variety of cell types. In this article we focus on adipocytes as local regulators of epithelial cell growth and their function during lactation. Several important considerations arise from such a discussion. There is a clear and close interrelationship between different stromal tissue types within the mammary fat pad and its adipocytes. Furthermore, these relationships are both stage- and species-dependent, although many questions remain unanswered regarding their roles in these different states. Several lines of evidence also suggest that adipocytes within the mammary fat pad may function differently from those in other fat depots. Finally, past and future technologies present a variety of opportunities to model these complexities in order to more precisely delineate the many potential functions of adipocytes within the mammary glands. A thorough understanding of the role for this cell type in the mammary glands could present numerous opportunities to modify both breast cancer risk and lactation performance

Beta diversity and nature reserve system design a case study from the Yukon, Canada

Design of protected areas has focused on setting targets for representation of biodiversity, but often these targets do not include prescriptions as to how large protected areas should be or where they should be located. Principles of island biogeography theory have been applied with some success, but they have limitations. The so-called SLOSS (single large or several small reserves) debate hinged on applications of island biogeography theory to protected areas but was resolved only to the point that parties agreed there might be different approaches in different situations. Although proponents on both sides of the SLOSS debate generally agree that replicating protected areas is desirable, it is difficult to determine how to replicate reserves in terms of number and spatial arrangement. More important, many targets for representation often do not address issues of species persistence. Here, we used a geographic information system in a study of disturbancesensitive mammals of the Yukon Territory, Canada, to design a protected-areas network that maintains a historical assemblage of species goals for component ecoregions. We simultaneously determined patterns of diversity as Whittaker’s beta and compositional turnover and examined how these two measures can give further insights into reserve location and spatial arrangement. Both regional heterogeneity and compositional turnover between nonadjacent sites were significant predictors of the number of protected areas necessary to represent mammals within each ecoregion. Thus, protected-area planners can use diversity measures to identify number and spacing of protected areas within ecologically bounded regions