Phylogeny versus body size as determinants of food web structure

Food webs are the complex networks of trophic interactions that stoke the metabolic fires of life. To understand what structures these interactions in natural communities, ecologists have developed simple models to capture their main architectural features. However, apparently realistic food webs can be generated by models invoking either predator-prey body-size hierarchies or evolutionary constraints as structuring mechanisms. As a result, this approach has not conclusively revealed which factors are the most important. Here we cut to the heart of this debate by directly comparing the influence of phylogeny and body size on food web architecture. Using data from 13 food webs compiled by direct observation, we confirm the importance of both factors. Nevertheless, phylogeny dominates in most networks. Moreover, path analysis reveals that the size-independent direct effect of phylogeny on trophic structure typically outweighs the indirect effect that could be captured by considering body size alone. Furthermore, the phylogenetic signal is asymmetric: closely related species overlap in their set of consumers far more than in their set of resources. This is at odds with several food web models, which take only the view-point of consumers when assigning interactions. The echo of evolutionary history clearly resonates through current food webs, with implications for our theoretical models and conservation priorities.

Are there developmentally distinct motor indicators of pain in preterm infants?

The aims of this study were to examine preterm infant reactions to pain in detail over prolonged time periods using multiple measures, and to assess the value of including specific body movements of the Neonatal Individualized Developmental Care and Assessment Program (NIDCAP) system to evaluate pain. Ten preterm infants born at 31 weeks mean gestational age (GA) and mean birth weight 1676 g were studied during a routine blood collection in a Level III neonatal intensive care unit (NICU). At 32-week post-conceptional age, computerized physiologic and video recordings were obtained continuously for 60 min (prior to, during and after lance). Motor and facial behaviors were coded independently, using the NIDCAP and the NFCS (Neonatal Facial Coding System), respectively, and compared with heart rate (HR) and oxygen saturation responses. Of the movements hypothesized to be stress cues in the NIDCAP model, extension of arms and legs (80%) and finger splay (70%) were the most common following lance. Contrary to the model, most infants (70%) had lower incidence of twitches and startles post-lance compared to baseline. Whereas all infants showed some NFCS response to lance, for three infants, the magnitude was low. HR increased and oxygen saturation decreased post-lance. Infants with more prior pain exposure, lower Apgar, and lower GA at birth, displayed more motor stress cues but less facial activity post-lance. Extension of extremities and finger splay, but not twitches and startles, from the NIDCAP, appear to be stress cues and show promise as clinical pain indicators to supplement facial and physiological pain measures in preterm infants.

Stress processes in caring for an end-of-life family member:Application of a theoretical model

Objectives: Family caregivers play a vital role in maintaining the lives of individuals with advanced illness living in the community. However, the responsibility of caregiving for an end-of-life family member can have profound consequences on the psychological, physical and financial well-being of the caregiver. While the literature has identified caregiver stress or strain as a complex process with multiple contributing factors, few comprehensive studies exist. This study examined a wide range of theory-driven variables contributing to family caregiver stress. Method: Data variables from interviews with primary family caregivers were mapped onto the factors within the Stress Process Model theoretical framework. A hierarchical multiple linear regression analysis was used to determine the strongest predictors of caregiver strain as measured by a validated composite index, the Caregiver Strain Index. Results: The study included 132 family caregivers across south-central/western Ontario, Canada. About half of these caregivers experienced high strain, the extent of which was predicted by lower perceived program accessibility, lower functional social support, greater weekly amount of time caregivers committed to the care recipient, younger caregiver age and poorer caregiver self-perceived health. Conclusion: This study examined the influence of a multitude of factors in the Stress Process Model on family caregiver strain, finding stress to be a multidimensional construct. Perceived program accessibility was the strongest predictor of caregiver strain, more so than intensity of care, highlighting the importance of the availability of community resources to support the family caregiving role.

Identifying research priorities on infections in older adults:Proceedings of an interdisciplinary workshop

Background: Infections pose a substantial burden to the health of older adults. In this report, we describe the proceedings of a workshop to formulate and prioritize research questions about infections in older adults using an interdisciplinary approach. Methods: Researchers from four sectors (basic science, clinical sciences, health services and epidemiology/determinants of health) and representatives from various Canadian local, provincial, and federal stakeholder groups were invited to a two-day workshop. Five multi-disciplinary groups and stakeholders from each of three healthcare settings (long term, acute care and community) discussed research priorities for each of the settings. Five to ten research questions were identified for each setting. Results: The research questions proposed ranged from risk factors and outcomes for different infections to the effect of nutrition on infection and the role of alternative and complementary medicine in treating infections. Health service issues included barriers to immunization, prolongation of hospital length of stay by infection, use of care paths for managing infections, and decision-making in determining the site of care for individuals with infections. Clinical questions included risk factor assessment for infection, the effectiveness of preventative strategies, and technology evaluation. Epidemiologic issues included the challenge of achieving a better understanding of respiratory infections in the community and determining the prevalence of colonization with multi-resistant bacteria. Conclusions: The questions are of direct relevance to researchers in a wide variety of fields. Bringing together a multi-disciplinary group of researchers to frame and prioritize research questions about aging is feasible, participants valued the opinions of people working in other areas.

Interobserver Reliability of Radiologists' Interpretations of Mobile Chest Radiographs for Nursing Home-Acquired Pneumonia

Objectives: To determine the interobserver reliability of radiologists' interpretations of mobile chest radiographs for nursing home-acquired pneumonia. Design: A cross-sectional reliability study. Setting: Nursing homes and an acute care hospital. Participants: Four radiologists reviewed 40 mobile chest radiographs obtained from residents of nursing homes who met a clinical definition of lower respiratory tract infections. Measurements: Radiologists were asked to interpret radiographs with respect to the film quality; presence, pattern, and extent of an infiltrate; and the presence of a pleural effusion or adenopathy. Interrater reliability was evaluated using the intraclass correlation coefficient derived from a 2-way random effects model. Results: On average the radiologists reported that 6 of the 40 films were of very good or excellent quality and 16 of the 40 were of fair or poor quality. When the finding of an infiltrate was dichotomized (0 = no; 1 = possible, probable, or definite) all 4 radiologists agreed on 21 of the 37 chest radiographs. The intraclass correlation coefficient for the presence or absence of infiltrates was 0.54 (95% confidence intervals [CI] 0.38 to 0.69). For the 14 radiographs where infiltrates were observed by all radiologists, intraclass correlation coefficients for the presence of pleural effusions was 0.08 (95% CI -0.10 to 0.41), hilar adenopathy 0.54 (95% CI 0.29 to 0.79), and mediastinal adenopathy 0.49 (95% CI 0.21 to 0.76). Conclusion: In conclusion, the interrater agreement among radiologists for mobile chest radiographs in establishing the presence or absence of an infiltrate can be judged to be "fair." Treatment decisions need to include clinical findings and should not be made based on radiographic findings alone. © 2006 American Medical Directors Association.

MHJ_0125 is an M42 glutamyl aminopeptidase that moonlights as a multifunctional adhesin on the surface of Mycoplasma hyopneumoniae

Bacterial aminopeptidases play important roles in pathogenesis by providing a source of amino acids from exogenous proteins, destroying host immunological effector peptides and executing posttranslational modification of bacterial and host proteins. We show that MHJ_0125 from the swine respiratory pathogen Mycoplasma hyopneumoniae represents a new member of the M42 class of bacterial aminopeptidases. Despite lacking a recognizable signal sequence, MHJ_0125 is detectable on the cell surface by fluorescence microscopy and LC-MS/MS of (i) biotinylated surface proteins captured by avidin chromatography and (ii) peptides released by mild trypsin shaving. Furthermore, surface-associated glutamyl aminopeptidase activity was detected by incubation of live M. hyopneumoniae cells with the diagnostic substrate H-Glu-AMC. MHJ_0125 moonlights as a multifunctional adhesin, binding to both heparin and plasminogen. Native proteomics and comparative modelling studies suggest MHJ_0125 forms a dodecameric, homopolymeric structure and provide insight into the positions of key residues that are predicted to interact with heparin and plasminogen. MHJ_0125 is the first aminopeptidase shown to both bind plasminogen and facilitate its activation by tissue plasminogen activator. Plasmin cleaves host extracellular matrix proteins and activates matrix metalloproteases, generating peptide substrates for MHJ_0125 and a source of amino acids for growth of M. hyopneumoniae. This unique interaction represents a new paradigm in microbial pathogenesis.

Temporal and geographical distribution of measles virus genotypes

The nucleotide sequence encoding the C terminus of the nucleocapsid protein of measles virus (MV) is the most variable in the genome. The sequence of this region is reported for 21 new MV strains and for virus RNA obtained from cases of subacute panencephalitis (SSPE) tissue. The nucleotide sequence of a total of 65 MV strains has been analysed using the CLUSTAL program to determine the relationships between the strains. An unrooted tree shows that eight different genotypes can be discerned amongst the sequences analysed so far. The data show that the C-terminal coding sequence of the nucleocapsid gene, although highly variable between strains, is stable in a given strain and does not appear to diverge in tissue culture. It therefore provides a good 'signature' sequence for specific genotypes. The sequence of this region can be used to discriminate new imported viruses from old 'endemic' strains of MV in a geographical area. The different genotypes are not geographically restricted although some appear to be the mainly 'endemic' types in large areas of the world. In global terms there appears to be at least four co-circulating genotypes of MV. The low level of divergence in the Edmonston lineage group isolated before 1970 indicates that some isolates are probably laboratory contaminants. This applies to some SSPE isolates such as the Halle, Mantooth and Horta-Barbosa strains as well as some wild-type isolates from that period.

Surgical checklist for cataract surgery:progress with the initiative by the Royal College of Ophthalmologists to improve patient safety

PurposeThe World Health Organisation (WHO) identified patient safety in surgery as an important public health matter and advised the adoption of a universal peri-operative surgical checklist. An adapted version of the WHO checklist has been mandatory in the National Health Service since 2010. Wrong intraocular lens (IOL) implantation is a particular safety concern in ophthalmology. The Royal College of Ophthalmologists launched a bespoke checklist for cataract surgery in 2010 to reduce the likelihood of preventable errors. We sought to ascertain the use of checklists in cataract surgery in 2012.Patients and methodsA survey of members of the Royal College of Ophthalmologists seeking views on the use of checklists in cataract surgery. Four hundred and sixty-nine completed responses were received (18% response rate).ResultsRespondents worked in England (75%), Scotland (11%), Wales (5%), Northern Ireland (2%), the Republic of Ireland (1%), and overseas (6%). Ninety-four per cent of respondents support the use of a checklist for cataract surgery and 85% say that they always use a checklist before cataract surgery. Sixty-seven per cent of cataract surgeons stated they undertake a pre-operative team brief. Thirty-six per cent use a cataract surgery checklist developed locally, 18% use the college's bespoke cataract surgery checklist, 39% use a generic surgical checklist, and 4% reported that they do not use a checklist.ConclusionNinety-three per cent of cataract surgeons responding to the questionnaire report using a surgical checklist and 67% use a team brief. However, only 54% use a checklist, which addresses the selection of the correct intraocular implant. We recommend wider adoption of checklists, which address risks relevant to cataract surgery, in particular the possibility of selection of an incorrect IOL.Eye advance online publication, 24 May 2013; doi:10.1038/eye.2013.101.

Effect of pH on the in vitro susceptibility of planktonic and biofilm-grown Proteus mirabilis to the quinolone antimicrobials

To examine the effect of elevated pH, as reported during urinary catheter infections, on quinolone activity against the urease-producing pathogen Proteus mirabilis.