Daily energy expenditure and water turnover in two breeds of laying hens kept in floor housing

Acknowledgements The authors thank Gabriele Kirchhof, Silke Werner, Klaus Gerling and Karsten Knop from the Institute of Animal Welfare and Animal Husbandry of the Friedrich-Loeffler-Institut for technical help and Catherine Hambly from the Institute of Biological and Environmental Sciences of the University of Aberdeen for the isotope analysis. Financial support statement This research received no specific grant from any funding agency, commercial or not-for-profit sectionPeer reviewedPublisher PD

Trapped in the darkness of the night: thermal and energetic constraints of daylight flight in bats

Bats are one of the most successful mammalian groups, even though their foraging activities are restricted to the hours of twilight and night-time. Some studies suggested that bats became nocturnal because of overheating when flying in daylight. This is because—in contrast to feathered wings of birds—dark and naked wing membranes of bats efficiently absorb short-wave solar radiation. We hypothesized that bats face elevated flight costs during daylight flights, since we expected them to alter wing-beat kinematics to reduce heat load by solar radiation. To test this assumption, we measured metabolic rate and body temperature during short flights in the tropical short-tailed fruit bat Carollia perspicillata at night and during the day. Core body temperature of flying bats differed by no more than 2°C between night and daytime flights, whereas mass-specific CO2 production rates were higher by 15 per cent during daytime. We conclude that increased flight costs only render diurnal bat flights profitable when the relative energy gain during daytime is high and risk of predation is low. Ancestral bats possibly have evolved dark-skinned wing membranes to reduce nocturnal predation, but a low degree of reflectance of wing membranes made them also prone to overheating and elevated energy costs during daylight flights. In consequence, bats may have become trapped in the darkness of the night once dark-skinned wing membranes had evolved

Attitudes to and Understanding of Risk of Acquisition of HIV Over Time: Design and Methods for an Internet-based Prospective Cohort Study Among UK Men Who Have Sex With Men (the AURAH2 Study)

Background: The annual number of new HIV infections among men who have sex with men (MSM) has risen in the UK and, of those HIV positive, the proportion undiagnosed is high. The prospective AURAH2 study aims to assess factors associated with HIV acquisition among MSM in the UK, and to investigate changes over time within individuals in sexual behaviour and HIV-testing practices. / Methods/Design: AURAH2 is a prospective study among MSM without diagnosed HIV, aiming to recruit up to 1000 sexually active MSM attending sexual health clinics in London and Brighton. Participants complete an initial paper-based questionnaire, followed by four monthly online follow-up questionnaires collecting socio-demographic, health and behavioural data, including sexual behaviour, recreational and other drug use, HIV testing practices and Pre-Exposure Prophylaxis use, over a planned three year period. / Discussion: The results from AURAH2 study will provide an important insight into established and emerging risk behaviours that may be associated with acquisition of HIV in MSM, in the UK, changes over time within individuals in sexual behaviour, and inform on HIV testing practices. This data will be crucial to inform future HIV prevention strategies

Self-reported difficulties with everyday function, cognitive symptoms, and cognitive function in people with HIV

BACKGROUND: We determined factors associated with self-reported decline in activities of daily living (ADLs) and symptoms of cognitive impairment in HIV positive (HIV+) adults in five European clinics. METHODS: HIV+ adults underwent computerized and pen-and-paper neuropsychological tests and questionnaires of cognitive symptoms and ADLs. We considered cognitive function in five domains, psychosocial factors and clinical parameters as potentially associated with symptoms. Separate regression analyses were used to determine factors associated with decline in ADL (defined as self-reported decline affecting ≥2 ADLs and attributed to cognitive difficulties) and self-reported frequency of symptoms of cognitive impairment. We also estimated the diagnostic accuracy of both questionnaires as tests for cognitive impairment. RESULTS: 448 patients completed the assessments (mean age 45.8 years, 84% male, 87% white, median CD4 count 550 cells/mm, median time since HIV diagnosis 9.9 years, 81% virologically suppressed [HIV-1 plasma RNA <50 copies/mL]). Ninety-six (21.4%) reported decline in ADLs and attributed this to cognitive difficulties. Self-reported decline in ADLs and increased symptoms of cognitive impairment were both associated with worse performance on some cognitive tests. There were also strong associations with financial difficulties, depressive and anxiety symptoms, unemployment, and longer time since HIV diagnosis. Both questionnaires performed poorly as diagnostic tests for cognitive impairment. CONCLUSION: Patients' own assessments of everyday function and symptoms were associated with objectively-measured cognitive function. However, there were strong associations with other psychosocial issues including mood and anxiety disorders and socioeconomic hardship. This should be considered when assessing HIV-associated cognitive impairment in clinical care or research studies

The Role of Critical Case Analysis in Interprofessional Education

Goals for interprofessional education include preparing students to work in collaborative practice, teaching them how to work in teams and to asses and improve the quality of patient care. (Barr, 2007, Thibault, 2013). Four core competency domains have been established to inform interprofessional education (Interprofessional Education Collaborative Expert Panel, 2011). These are ethics/values, roles/responsibilities, interprofessional communication and teams/teamwork. Various pedagogical approaches have been used to help students meet these competencies. The Josiah Macy, Jr. Foundation (2013) recommends development and implementation of innovative models to link interprofessional education and practice. Thibault (2013) recommends students engage in “real work” as part of their interprofessional education experience

Assigning stranded bottlenose dolphins to source stocks using stable isotope ratios following the Deepwater Horizon oil spill

The potential for stranded dolphins to serve as a tool for monitoring free-ranging populations would be enhanced if their stocks of origin were known. We used stable isotopes of carbon, nitrogen, and sulfur from skin to assign stranded bottlenose dolphins Tursiops truncatus to different habitats, as a proxy for stocks (demographically independent populations), following the Deepwater Horizon oil spill. Model results from biopsy samples collected from dolphins from known habitats (n = 205) resulted in an 80.5% probability of correct assignment. These results were applied to data from stranded dolphins (n = 217), resulting in predicted assignment probabilities of 0.473, 0.172, and 0.355 to Estuarine, Barrier Island (BI), and Coastal stocks, respectively. Differences were found west and east of the Mississippi River, with more Coastal dolphins stranding in western Louisiana and more Estuarine dolphins stranding in Mississippi. Within the Estuarine East Stock, 2 groups were identified, one predominantly associated with Mississippi and Alabama estuaries and another with western Florida. δ15N values were higher in stranded samples for both Estuarine and BI stocks, potentially indicating nutritional stress. High probabilities of correct assignment of the biopsy samples indicate predictable variation in stable isotopes and fidelity to habitat. The power of δ34S to discriminate habitats relative to salinity was essential. Stable isotopes may provide guidance regarding where additional testing is warranted to confirm demographic independence and aid in determining the source habitat of stranded dolphins, thus increasing the value of biological data collected from stranded individuals.Publisher PDFPeer reviewe

AMPK is essential for energy homeostasis regulation and glucose sensing by POMC and AgRP neurons

Hypothalamic AMP-activated protein kinase (AMPK) has been suggested to act as a key sensing mechanism, responding to hormones and nutrients in the regulation of energy homeostasis. However, the precise neuronal populations and cellular mechanisms involved are unclear. The effects of long-term manipulation of hypothalamic AMPK on energy balance are also unknown. To directly address such issues, we generated POMC alpha 2KO and AgRP alpha 2KO mice lacking AMPK alpha 2 in proopiomelanocortin- (POMC-) and agouti-related protein-expressing (AgRP-expressing) neurons, key regulators of energy homeostasis. POMC alpha 2KO mice developed obesity due to reduced energy expenditure and dysregulated food intake but remained sensitive to leptin. in contrast, AgRPa2KO mice developed an age-dependent lean phenotype with increased sensitivity to a melanocortin agonist. Electrophysiological studies in AMPK alpha 2-deficient POMC or AgRP neurons revealed normal leptin or insulin action but absent responses to alterations in extracellular glucose levels, showing that glucose-sensing signaling mechanisms in these neurons are distinct from those pathways utilized by leptin or insulin. Taken together with the divergent phenotypes of POMC alpha 2KO and AgRP alpha 2KO mice, our findings suggest that while AMPK plays a key role in hypothalamic function, it does not act as a general sensor and integrator of energy homeostasis in the mediobasal hypothalamus

Prospective association of social circumstance, socioeconomic, lifestyle and mental health factors with subsequent hospitalisation over 6–7 year follow up in people living with HIV

Background: Predictors of hospitalisation in people with HIV (PLHIV) in the contemporary treatment era are not well understood. / Methods: This ASTRA sub-study used clinic data linkage and record review to determine occurrence of hospitalisations among 798 PLHIV from baseline questionnaire (February to December 2011) until 1 June 2018. Associations of baseline social circumstance, socioeconomic, lifestyle, mental health, demographic and clinical factors with repeated all-cause hospitalisation from longitudinal data were investigated using Prentice-Williams-Peterson models. Associations were also assessed in 461 individuals on antiretroviral therapy (ART) with viral load ≤50 copies/ml and CD4 count ≥500 cells/ µl. / Findings: Rate of hospitalisation was 5.8/100 person-years (95% CI: 5.1–6.5). Adjusted for age, demographic group and time with diagnosed HIV, the following social circumstance, socioeconomic, lifestyle and mental health factors predicted hospitalisation: no stable partner (adjusted hazard ratio (aHR)=1.59; 95% CI=1.16–2.20 vs living with partner); having children (aHR=1.50; 1.08–2.10); non-employment (aHR=1.56; 1.07–2.27 for unemployment; aHR=2.39; 1.70–3.37 for sick/disabled vs employed); rented housing (aHR=1.72; 1.26–2.37 vs homeowner); not enough money for basic needs (aHR=1.82; 1.19–2.78 vs enough); current smoking (aHR=1.39; 1.02–1.91 vs never); recent injection-drug use (aHR=2.11; 1.30–3.43); anxiety symptoms (aHRs=1.39; 1.01–1.91, 2.06; 1.43–2.95 for mild and moderate vs none/minimal); depressive symptoms (aHRs=1.67; 1.17–2.38, 1.91; 1.30–2.78 for moderate and severe vs none/minimal); treated/untreated depression (aHRs=1.65; 1.03–2.64 for treated depression only, 1.87; 1.39–2.52 for depressive symptoms only; 1.53; 1.05–2.24; for treated depression and depressive symptoms, versus neither). Associations were broadly similar in those with controlled HIV and high CD4. / Interpretation: Social circumstance, socioeconomic disadvantage, adverse lifestyle factors and poorer mental health are strong predictors of hospitalisation in PLHIV, highlighting the need for targeted interventions and care. / Funding: British HIV Association (BHIVA) Research Award (2017); SMR funded by a PhD fellowship from the Royal Free Charity

Evidence of a metabolic memory to early-life dietary restriction in male C57BL/6 mice

&lt;p&gt;Background: Dietary restriction (DR) extends lifespan and induces beneficial metabolic effects in many animals. What is far less clear is whether animals retain a metabolic memory to previous DR exposure, that is, can early-life DR preserve beneficial metabolic effects later in life even after the resumption of ad libitum (AL) feeding. We examined a range of metabolic parameters (body mass, body composition (lean and fat mass), glucose tolerance, fed blood glucose, fasting plasma insulin and insulin-like growth factor 1 (IGF-1), insulin sensitivity) in male C57BL/6 mice dietary switched from DR to AL (DR-AL) at 11 months of age (mid life). The converse switch (AL-DR) was also undertaken at this time. We then compared metabolic parameters of the switched mice to one another and to age-matched mice maintained exclusively on an AL or DR diet from early life (3 months of age) at 1 month, 6 months or 10 months post switch.&lt;/p&gt; &lt;p&gt;Results: Male mice dietary switched from AL-DR in mid life adopted the metabolic phenotype of mice exposed to DR from early life, so by the 10-month timepoint the AL-DR mice overlapped significantly with the DR mice in terms of their metabolic phenotype. Those animals switched from DR-AL in mid life showed clear evidence of a glycemic memory, with significantly improved glucose tolerance relative to mice maintained exclusively on AL feeding from early life. This difference in glucose tolerance was still apparent 10 months after the dietary switch, despite body mass, fasting insulin levels and insulin sensitivity all being similar to AL mice at this time.&lt;/p&gt; &lt;p&gt;Conclusions: Male C57BL/6 mice retain a long-term glycemic memory of early-life DR, in that glucose tolerance is enhanced in mice switched from DR-AL in mid life, relative to AL mice, even 10 months following the dietary switch. These data therefore indicate that the phenotypic benefits of DR are not completely dissipated following a return to AL feeding. The challenge now is to understand the molecular mechanisms underlying these effects, the time course of these effects and whether similar interventions can confer comparable benefits in humans.&lt;/p&gt

Validation of the doubly labeled water method using off-axis integrated cavity output spectroscopy and isotope ratio mass spectrometry

This work was supported by an NIH Small Business Innovation (SBIR) research Grant (R44 DK093362), as well as support from the Colorado Nutrition and Obesity Research Center (P30 DK048520) and the Colorado Clinical and Translational Science Institute (UL1 RR025780). Dr. Melanson is also supported by resources from the Geriatric Research, Education, and Clinical Center at the Denver VA Medical Center.Peer reviewedPostprin