Nutritional correlates of koala persistence in a low-density population

It is widely postulated that nutritional factors drive bottom-up, resource-based patterns in herbivore ecology and distribution. There is, however, much controversy over the roles of different plant constituents and how these influence individual herbivores and herbivore populations. The density of koala (Phascolarctos cinereus) populations varies widely and many attribute population trends to variation in the nutritional quality of the eucalypt leaves of their diet, but there is little evidence to support this hypothesis. We used a nested design that involved sampling of trees at two spatial scales to investigate how leaf chemistry influences free-living koalas from a low-density population in south east New South Wales, Australia. Using koala faecal pellets as a proxy for koala visitation to trees, we found an interaction between toxins and nutrients in leaves at a small spatial scale, whereby koalas preferred trees with leaves of higher concentrations of available nitrogen but lower concentrations of sideroxylonals (secondary metabolites found exclusively in eucalypts) compared to neighbouring trees of the same species. We argue that taxonomic and phenotypic diversity is likely to be important when foraging in habitats of low nutritional quality in providing diet choice to tradeoff nutrients and toxins and minimise movement costs. Our findings suggest that immediate nutritional concerns are an important priority of folivores in low-quality habitats and imply that nutritional limitations play an important role in constraining folivore populations. We show that, with a careful experimental design, it is possible to make inferences about populations of herbivores that exist at extremely low densities and thus achieve a better understanding about how plant composition influences herbivore ecology and persistence.IW and WF received a grant from New South Wales (NSW) Department of Environment, Climate Change & Water

Clinical practice guidelines for the prevention and treatment of EGFR inhibitor-associated dermatologic toxicities

Background Epidermal growth factor receptor inhibitors (EGFRI) produce various dermatologic side effects in the majority of patients, and guidelines are crucial for the prevention and treatment of these untoward events. The purpose of this panel was to develop evidence-based recommendations for EGFRI-associated dermatologic toxicities. Methods A multinational, interdisciplinary panel of experts in supportive care in cancer reviewed pertinent studies using established criteria in order to develop first-generation recommendations for EGFRI-associated dermatologic toxicities. Results Prophylactic and reactive recommendations for papulopustular (acneiform) rash, hair changes, radiation dermatitis, pruritus, mucositis, xerosis/fissures, and paronychia are presented, as well as general dermatologic recommendations when possible. Conclusion Prevention and management of EGFRI-related dermatologic toxicities is critical to maintain patients’ health-related quality of life and dose intensity of antineoplastic regimens. More rigorous investigation of these toxicities is warranted to improve preventive and treatment strategies

Current Topical and Systemic Therapies for Itch

Itch is a common distressing symptom which may be caused by multifactorial aetiologies including inflammatory skin diseases, systemic diseases, neuropathic conditions and psychogenic disorders. Itch is a term used synonymously with pruritus and is defined as acute if it lasts less than 6 weeks or chronic if it persists for more than 6 weeks. It can have the same impact on the quality of life as chronic pain and shares many of the same pathophysiological pathways. Depending on the aetiology of the itch, different pathogenic mechanisms have been postulated with a number of mediators identified. These include histamine, leukotrienes, proteases, neuropeptides, cytokines and opioids, which may activate peripheral itch-mediating C-fibres via receptors on the nerve terminals and central neuronal pathways. Therefore, there is no single universally effective anti-itch treatment available. First-line treatments for itch include topical therapies, such as emollients, mild cleansers (low pH), topical anaesthetics, steroids, calcineurin inhibitors and coolants (menthol). Treatment with systemic therapies can vary according to the aetiology of the chronic itch. Non-sedating antihistamines are helpful in conditions such as urticaria where the itch is primarily histamine mediated. Although the itch of eczema is not mediated by histamine, sedating antihistamines at night are helpful to break the itch-scratch cycle. Chronic itch may also be treated with other systemic therapies, such as anticonvulsants, antidepressants as well as mu-opioid antagonists, kappa-opioid agonists and phototherapy, depending on the cause of the itch. This article summarises the topical and systemic therapies available with our current understanding of the pathophysiology of itch

Role of genetic and non-genetic factors in the etiology of Graves' disease

n spite of the advancements in understanding the pathogenic mechanisms of Graves' disease (GD), its ultimate cause remains elusive. The majority of investigators agree that GD is likely a multifactorial disease, due to a complex interplay of genetic and non-genetic factors that lead to the loss of immune tolerance to thyroid antigens and to the initiation of a sustained autoimmune reaction. Twin and family studies support a role of genetic factors, among which the HLA complex, CD40, CTLA-4, PTPN22, FCRL3, thyroglobulin, and the TSH receptor may be involved. Among non-genetic factors, iodine, infections, psychological stress, gender, smoking, thyroid damage, vitamin D, selenium, immune modulating agents, and periods of immune reconstitution may contribute the development of the diseases. Here we review in detail the respective role of genetic and non-genetic factors in the etiology of GD, taking advantage of the great bulk of data generated especially over the past 30 years