Search

Abstract: Predator control is often implemented with the intent of disrupting top‐down regulation in sensitive prey populations. However, ambiguity surrounding the efficacy of predator management, as well as the strength of top‐down effects of predators in general, is often exacerbated by the spatially implicit analytical approaches used in assessing data with explicit spatial structure. Here, we highlight the importance of considering spatial context in the case of a predator control study in south‐central Utah. We assessed the spatial match between aerial removal risk in coyotes (Canis latrans) and mule deer (Odocoileus hemionus) resource selection during parturition using a spatially explicit, multi‐level Bayesian model. With our model, we were able to evaluate spatial congruence between management action (i.e., coyote removal) and objective (i.e., parturient deer site selection) at two distinct scales: the level of the management unit and the individual coyote removal. In the case of the former, our results indicated substantial spatial heterogeneity in expected congruence between removal risk and parturient deer site selection across large areas, and is a reflection of logistical constraints acting on the management strategy and differences in space use between the two species. At the level of the individual removal, we demonstrated that the potential management benefits of a removed coyote were highly variable across all individuals removed and in many cases, spatially distinct from parturient deer resource selection. Our methods and results provide a means of evaluating where we might anticipate an impact of predator control, while emphasizing the need to weight individual removals based on spatial proximity to management objectives in any assessment of large‐scale predator control. Although we highlight the importance of spatial context in assessments of predator control strategy, we believe our methods are readily generalizable in any management or large‐scale experimental framework where spatial context is likely an important driver of outcomes. [ABSTRACT FROM AUTHOR]

Understanding the relative effects of climate, harvest, and density dependence on population dynamics is critical for guiding sound population management, especially for ungulates in arid and semiarid environments experiencing climate change. To address these issues for bison in southern Utah, USA, we applied a Bayesian state-space model to a 72-yr time series of abundance counts. While accounting for known harvest (as well as live removal) from the population, we found that the bison population in southern Utah exhibited a strong potential to grow from low density (β0 = 0.26; Bayesian credible interval based on 95% of the highest posterior density [BCI] = 0.19-0.33), and weak but statistically significant density dependence (β1 = -0.02, BCI = -0.04 to -0.004). Early spring temperatures also had strong positive effects on population growth (βfat1 = 0.09, BCI = 0.04-0.14), much more so than precipitation and other temperature-related variables (model weight. three times more than that for other climate variables). Although we hypothesized that harvest is the primary driving force of bison population dynamics in southern Utah, our elasticity analysis indicated that changes in early spring temperature could have a greater relative effect on equilibrium abundance than either harvest or the strength of density dependence. Our findings highlight the utility of incorporating elasticity analyses into state-space population models, and the need to include climatic processes in wildlife management policies and planning. [ABSTRACT FROM AUTHOR]

Acquired resistance to BRAF inhibitors often involves MAPK re‐activation, yet the MEK inhibitor trametinib showed minimal clinical activity in melanoma patients that had progressed on BRAF‐inhibitor therapy. Selective ERK inhibitors have been proposed as alternative salvage therapies. We show that ERK inhibition is more potent than MEK inhibition at suppressing MAPK activity and inhibiting the proliferation of multiple BRAF inhibitor resistant melanoma cell models. Nevertheless, melanoma cells often failed to undergo apoptosis in response to ERK inhibition, because the relief of ERK‐dependent negative feedback activated RAS and PI3K signalling. Consequently, the combination of ERK and PI3K/mTOR inhibition was effective at promoting cell death in all resistant melanoma cell models, and was substantially more potent than the MEK/PI3K/mTOR inhibitor combination. Our data indicate that a broader targeting strategy concurrently inhibiting ERK, rather than MEK, and PI3K/mTOR may circumvent BRAF inhibitor resistance, and should be considered during the clinical development of ERK inhibitors. Highlights: We examine the activity of the MEK and ERK inhibition in models of melanoma BRAF inhibitor resistance.ERK inhibitors more efficiently suppress MAPK signalling in these models.Despite cell cycle arrest ERK inhibitors can only induce apoptosis in a subset of resistance models.Survival is due to ERK‐dependent negative feedback activated RAS and PI3K signalling.Combined ERK and PI3K/mTOR inhibition was effective at promoting cell death in all models. [ABSTRACT FROM AUTHOR]

The 2010 7th International Melanoma Congress sponsored by the Society for Melanoma Research and held in Sydney, Australia, was held together with the International Melanoma and Skin Cancer Centers group and the International Melanoma Pathology Study Group. As a consequence, there were over 900 registrants that included a wide range of clinicians (surgeons, medical oncologists, dermatologists) specialising in the management of melanoma as well as scientists and students carrying out laboratory-based research in melanoma. There was a general consensus that this grouping of clinicians, pathologists and scientists was mutually advantageous and plans are afoot to continue this grouping in future meetings. The meeting was dominated by the advances being made in treatment of melanoma with selective BRAF inhibitors but interest in epithelial mesenchymal transition and phenotypic changes in melanoma was apparent in many of the talks. The authors have attempted to capture many of the new developments in melanoma research but apologize to those speakers and poster presenters who had equally important findings not captured in these summaries. [ABSTRACT FROM AUTHOR]

Patients with thick, primary melanoma and regional lymph-node metastases are at moderate to high risk of recurrence and death, despite apparent complete surgical removal. Immune responses can be demonstrated against melanoma and this has prompted the conduct of a number of randomized trials of immunotherapy. Several trials have been completed and show minimal benefit in prolonging survival or recurrence from melanoma. Similarly, a large number of trials has been conducted to test the efficacy of α-2-interferon (IFN-α2) in therapy. Clear benefit in recurrence-free survival was shown in several trials, however there is a lack of convincing evidence of an effect on overall survival. Several trials of vaccine and IFN-α2 therapy are still in progress and their results are awaited with great interest. The use of highdose IFN-α2 therapy remains a contentious subject, however available evidence suggests the standard of care remains good surgical management. (Intern Med J 2003; 33:31 41) [ABSTRACT FROM AUTHOR]

The pathogenesis of Vogt-Koyanagi-Harada syndrome is poorly understood. A unifying mechanism for its diverse clinical manifestations affecting central nervous system, eye, integument and auditory system has not been found, although many authors have suggested that the features of the disease are the result of autoimmune responses. We performed immunological studies on two patients with Vogt-Koyanagi-Harada syndrome. In one case antibodies to melanoma cells in cytotoxic assay were detected, which it was thought may indicate the presence of antibodies to melanocytes. In the second patient three clones of interieukin-2-dependent T cells were isolated which appeared to have specificity in both cytotoxic and proliferative assays to cultured normal melanocytes and to three allogeneic melanoma cells. These findings further support a role for autoimmunity to pigmented cells in the pathogenesis of Vogt-Koyanagi-Harada syndrome. However, the precise role of autoimmunity in this disease is yet to be established. [ABSTRACT FROM AUTHOR]

Rat lymphoma cells sensitized with antibody and incubated with normal macrophages were shown to become resistant to damage from cytotoxic antibody and complement or cytotoxic lymphocytes. Both lymphoma specific antibody and normal macrophages were required to produce protection. The cytotoxic effect of lymphocytes or antibody with complement and the protective effect of antibody with macrophages was assessed by 51Cr release and by loss of capacity of iymphoma cells to transfer the disease to syngeneic rats. No cytotoxic effect could be attributed to macrophages from sensitized allogeneic rats. Inhibition of phagocytosis by Cytochalasin B did not destroy the capacity of macrophages to protect lymphoma cells. Sodium fluoride, however, did block the protective effect. It is envisaged that this protective phenomenon may be of importance in understanding some aspects of growth of tumours in vivo despite the presence of immune cytotoxic mechanisms. [ABSTRACT FROM AUTHOR]

Reports on a case of vaccinia necrosis in a 66-year-old man presented with a large erythemathus eruption in his right upper arm. Overview of the development of the complication from smallpox vaccination with vaccinia; Attribution of the complication to chronic lymphocytic leukemia in the patient; Manifestations of the disease and other complications; Patient characteristics and medical history; Treatment.

A letter to the editor is presented in response to J. Hoyle and S. Yentis' review of block height assessment before caesarean section and the author's agreement that the lack of a gold standard can lead to confusion.

An abstract of the article "Defining competence for workplace based assessment & x2013; a pragmatic and thorough method," by P. Hersey and D. Laws is presented.

A response to a letter to the editor about the article "Oxygen wastage," that was published in the previous issue is presented.

A letter to the editor is presented in response to the article "Oxygen wastage from anaesthetic machines," that was published in the previous issue.