Dynamics of macronutrient self-medication and illness-induced anorexia in virally infected insects

Some animals change their feeding behaviour when infected with parasites, seeking out substances that enhance their ability to overcome infection. This 'self-medication' is typically considered to involve the consumption of toxins, minerals or secondary compounds. However, recent studies have shown that macronutrients can influence the immune response and that pathogen-challenged individuals can self-medicate by choosing a diet rich in protein and low in carbohydrates. Infected individuals might also reduce food intake when infected (i.e. illness-induced anorexia). Here, we examine macronutrient self-medication and illness-induced anorexia in caterpillars of the African armyworm (Spodoptera exempta) by asking how individuals change their feeding decisions over the time course of infection with a baculovirus. We measured self-medication behaviour across several full-sib families to evaluate the plasticity of diet choice and underlying genetic variation. Larvae restricted to diets high in protein (P) and low in carbohydrate (C) were more likely to survive a virus challenge than those restricted to diets with a low P : C ratio. When allowed free choice, virus-challenged individuals chose a higher protein diet than controls. Individuals challenged with either a lethal or sublethal dose of virus increased the P : C ratio of their chosen diets. This was mostly due to a sharp decline in carbohydrate intake, rather than an increased intake of protein, reducing overall food intake, consistent with an illness-induced anorexic response. Over time the P : C ratio of the diet decreased until it matched that of controls. Our study provides the clearest evidence yet for dietary self-medication using macronutrients and shows that the temporal dynamics of feeding behaviour depends on the severity and stage of the infection. The strikingly similar behaviour shown by different families suggests that self-medication is phenotypically plastic and not a consequence of genetically based differences in diet choice between families. © 2013 British Ecological Society.

Layered RF Phantom Characterization for Wireless Medical Vital Sign Monitors

Wearable antenna performance measurements were used to characterize a synthetic variable layered phantom testbed, representative of human tissue for operation in the 868/915 MHz, and 2400 MHz industrial, scientific and medical frequency bands. Antenna radiation efficiency measurements on the phantom were compared with measurements on the thorax region of a human test subject. The results show that the phantom is representative of the human body for the application of wireless vital sign monitors, where conductive connections are made to the tissue.

Evaluation of the contribution of theatre attendance to medical undergraduate neuroscience teaching - a pilot study.

Introduction: Medical students often attend the neurosurgical theatre during their clinical neurosciences attachment. However, few studies have been performed to objectively assess the value of this theatre-based learning experience. The main aim of this study was to explore student perceptions on the contribution of neurosurgical theatre attendance to clinical neuroscience teaching.

Materials and Methods: Third-year medical students undergoing their 2-week clinical neurosciences rotation at the Royal Hospitals Belfast were invited to participate in this study. A multi-method strategy was employed using a survey questionnaire comprising of closed and open-ended questions followed by semi-structured interviews to gain a greater 'in-depth' analysis of the potential contribution of neurosurgical theatre attendance to neuroscience teaching.

Results: Based on the completed survey responses of 22 students, the overall experience of neurosurgical theatre-based learning was a positive one. 'In-depth' analysis from semi-structured interviews indicated that students felt that some aspects of their neurosurgical theatre attendance could be improved. Better preparation such as reading up on the case in hand and an introduction to simple theatre etiquette to put the student at ease (in particular, for students who had never attended theatre previously), would improve the learning experience. In addition, having an expectation of what students are expected to learn in theatre making it more learning outcomes-based would probably make it feel a more positive experience by the student.

Conclusions: The vast majority of students acknowledged the positive learning outcomes of neurosurgical theatre attendance and felt that it should be made a mandatory component of the curriculum.

Revascularization versus medical therapy for renal-artery stenosis

Percutaneous revascularization of the renal arteries improves patency in atherosclerotic renovascular disease, yet evidence of a clinical benefit is limited.

Childhood trauma and the risk of violence in adulthood in a population with a psychotic illness.

There are strong links between childhood trauma and the risk of violence (Ford et al., 2007). Despite evidence that people with psychotic disorders are at a higher risk of violence than the general population (Witt et al., 2013) there have been few studies that have examined the trauma-violence link in this population (Spidel et al., 2010). This study explored the association between a history of childhood trauma (abuse, neglect and conflict-related trauma) and the risk of violence in adults with psychotic disorders. The strongest associations with the risk of violence were found for sexual abuse (r = .32, p < .05) and the impact of community conflict (r = .32, p < .05). An accumulative effect of trauma was found using a hierarchical regression (adjusted R2 = .14, F(2,37) = 4.23, p < .05). There are implications for applying models of violence to psychosis, risk assessment and treatment of people with psychotic disorders as well as informing trauma models and protective factors for children in conflict-affected regions.