Major histocompatibility complex (MHC) class II-positive dendritic cells in the rat iris - In situ development from MHC class II-negative precursors

Purpose. To examine the postnatal development of major histocompatibility complex (MHC) class II-positive dendritic cells (DC) in the iris of the normal rat eye. Methods. Single-and double-color immunomorphologic studies were performed on whole mounts prepared from rat iris taken at selected postnatal ages (2 to 3 days to 78 weeks). Immunopositive cells were enumerated, using a quantitative light microscope, and MHC class II expression on individual cells was assessed by microdensitometric analysis. Results. Major histocompatibility class II-positive DCs in the iris developed in an age-dependent manner and reached adult-equivalent density and structure at approximately 10 weeks of age, considerably later than previously described in other DC populations in the rat. In contrast, the anti-rat DC monoclonal antibody OX62 revealed a population of cells present at adult-equivalent levels as early as 3 weeks after birth. Dual-color immunostaining and microdensitometric analysis demonstrated that during postnatal growth, development of the network of MHC class II-positive DCs was a consequence of the progressive increase in expression of MHC class II antigen by OX62-positive cells. Conclusions. During postnatal growth, the DC population of the iris develops initially as an OX62-positive-MHC class II-negative population, which then develops increasing MHC class II expression in situ and finally resembles classic DC populations in other tissue sites. Maturation of the iris DC population is temporally delayed compared with time to maturation in other tissue sites in the rat.

Sibling competition and parental control: Patterns of begging in parrots

Begging and food allocation patterns are the outcome of complex and repeated interactions between parents and young. In most systems studied, food allocation is regulated by begging and scramble competition. In contrast, little is understood about how nestling solicitation behaviours will evolve in systems where parents engage in complex patterns of food allocation. Parrots appear to be an excellent group in which to examine the shifting balance between sibling competition and parental control. Studies to date have shown that levels of sibling competition within parrot broods are low, possibly in response to parental control over food distribution. I assess what is known about the function of nestling begging in parrots and evaluate why begging signals appear to function differently in this group.

Rural community pharmacists integrating care for people with complex health needs

The project involves rural/regional community pharmacists integrating care for complex needs patients and delivering a range of services, based on a care plan developed collaboratively with the GP and the consumer. The pharmacist will coordinate other services based on the multidisciplinary care plan. This research follows a successful pilot project and offers an opportunity to investigate new health service delivery in rural areas for patients at greater health related risk. Care integration will be compared to usual care, with outcomes relating to medication and health service usage, as well as clinical and quality of life outcomes being compared

Compartmentalization of Ras proteins

The Ras GTPases operate as molecular switches that link extracellular stimuli with a diverse range of biological outcomes. Although many studies have concentrated on the protein-protein interactions within the complex signaling cascades regulated by Ras, it is becoming clear that the spatial orientation of different Ras isoforms within the plasma membrane is also critical for their function. H-Ras, N-Ras and K-Ras use different membrane anchors to attach to the plasma membrane. Recently it has been shown that these anchors also act as trafficking signals that direct palmitoylated H-Ras and N-Ras through the exocytic pathway to the cell surface but divert polybasic K-Ras around the Golgi to the plasma membrane via an as yet-unidentified-route. Once at the plasma membrane, H-Ras and :K-Ras operate in different microdomains. K-Ras is localized predominantly to the disordered plasma membrane, whereas H-Ras exists in a GTP-regulated equilibrium between disordered plasma membrane and cholesterol-rich lipid rafts. These observations provide a likely explanation for the increasing number of biological differences being identified between the otherwise highly homologous Ras isoforms and raise interesting questions about the role membrane microlocalization plays in determining the interactions of Ras with its effecters and exchange factors.