3,215 research outputs found

    The impact of obesity on skeletal muscle strength and structure through adolescence to old age.

    Get PDF
    Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated

    Combined effects of body composition and ageing on joint torque, muscle activation and co-contraction in sedentary women

    Get PDF
    This study aimed to establish the interplay between body mass, adiposity, ageing and determinants of skeletal muscle strength. One hundred and two untrained healthy women categorised by age into young (Y) (mean ± SD, 26.7 ± 9.4 years) vs. old (O) (65.1 ± 7.2 years) were assessed for body fat, lean mass, plantar flexion and dorsiflexion maximum voluntary isometric contraction (MVC) torque, muscle activation capacity and antagonist muscle co-contraction. MVC torque normalised to body mass in the obese group was 35 and 29 % lower (p < 0.05) in Y and 34 and 31 % lower (p < 0.05) in O, compared with underweight and normal weight individuals, respectively. Y with ≥40 % body fat had significantly lower activation than Y with <40 % body fat (88.3 vs. 94.4 %, p < 0.05), but O did not exhibit this effect. Co-contraction was affected by ageing (16.1 % in O vs. 13.8 % in Y, p < 0.05) but not body composition. There were significant associations between markers of body composition, age, strength and activation capacity, with the strongest correlation between muscle strength and total body mass (r = 0.508 in Y, p < 0.001, vs. r = 0.204 in O, p < 0.01). Furthermore, the age-related loss in plantar flexion (PF) MVC torque was exacerbated in obese compared to underweight, normal weight and overweight individuals (-0.96 vs. -0.54, -0.57 and -0.57 % per year, p < 0.05). The negative impact of adiposity on muscle performance is associated with not only muscular but also neural factors. Overall, the effects of ageing and obesity on this system are somewhat cumulative. © 2014 The Author(s)

    Maternal personality traits, antenatal depressive symptoms and the postpartum mother-infant relationship: a prospective observational study

    Get PDF
    PURPOSE: Maternal depression has been associated with bonding difficulties and lower maternal sensitivity in observed mother-infant interactions. However, little research has examined the impact of disordered personality traits in mothers on these outcomes. We investigated the association between disordered personality traits in mothers measured during pregnancy and postnatal (a) self-reported bonding with infant; (b) observational mother-infant interactions. // METHODS: Five hundred fifty-six women were recruited during early pregnancy and subsequently followed up at mid-pregnancy (approximately 28 weeks' gestation) and when infants were aged approximately 3 months (n = 459). During early pregnancy, data were collected on disordered personality traits (using the Standardised Assessment of Personality Abbreviated Scale) and depressive symptoms (using the Edinburgh Postnatal Depression Scale). At 3 months postpartum, self-reported perceived bonding (using the Postpartum Bonding Questionnaire) were collected. A sub-sample of women additionally provided observational mother-infant interaction data (n = 206) (coded using the Child-Adult Relationship Experimental Index). // RESULTS: Higher disordered personality traits was not associated with maternal perceptions of bonding impairment, but was associated with reduced maternal sensitivity during observational mother-infant interactions [adjusted for age, education, having older children, substance misuse prior to pregnancy, infant sex and gestational age: coefficient = - 0.28, 95% CI = - 0.56 to - 0.00, p < 0.05]. After adjusting for depressive symptoms, the association was attenuated [coefficient = - 0.19, 95% CI = - 0.48 to 0.11, p = 0.217]. // CONCLUSIONS: Mothers with disordered personality traits did not perceive themselves as having bonding impairments with their infants but were less sensitive during observed interactions, though depressive symptoms attenuated this relationship. Both depression and disordered personality traits need to be addressed to optimize mother-infant interactions

    A short-term mouse model that reproduces the immunopathological features of rhinovirus-induced exacerbation of COPD

    Full text link
    © 2015 The Author(s). Viral exacerbations of chronic obstructive pulmonary disease (COPD), commonly caused by rhinovirus (RV) infections, are poorly controlled by current therapies. This is due to a lack of understanding of the underlying immunopathological mechanisms. Human studies have identified a number of key immune responses that are associated with RV-induced exacerbations including neutrophilic inflammation, expression of inflammatory cytokines and deficiencies in innate anti-viral interferon. Animal models of COPD exacerbation are required to determine the contribution of these responses to disease pathogenesis. We aimed to develop a short-term mouse model that reproduced the hallmark features of RV-induced exacerbation of COPD. Evaluation of complex protocols involving multiple dose elastase and lipopolysaccharide (LPS) administration combined with RV1B infection showed suppression rather than enhancement of inflammatory parameters compared with control mice infected with RV1B alone. Therefore, these approaches did not accurately model the enhanced inflammation associated with RV infection in patients with COPD compared with healthy subjects. In contrast, a single elastase treatment followed by RV infection led to heightened airway neutrophilic and lymphocytic inflammation, increased expression of tumour necrosis factor (TNF)-α, C-X-C motif chemokine 10 (CXCL10)/IP-10 (interferon γ-induced protein 10) and CCL5 [chemokine (C-C motif) ligand 5]/RANTES (regulated on activation, normal T-cell expressed and secreted), mucus hypersecretion and preliminary evidence for increased airway hyper-responsiveness compared with mice treated with elastase or RV infection alone. In summary, we have developed a new mouse model of RV-induced COPD exacerbation that mimics many of the inflammatory features of human disease. This model, in conjunction with human models of disease, will provide an essential tool for studying disease mechanisms and allow testing of novel therapies with potential to be translated into clinical practice

    Observational Properties of Jets in Active Galactic Nuclei

    Full text link
    Parsec scale jet properties are shortly presented and discussed. Observational data are used to derive constraints on the jet velocity and orientation, the presence of velocity structures, and the connection between the pc and kpc scale. Two peculiar sources with limb-brightened jets: 1144+35 and Mkn 501 are discussed in detail.Comment: 13 pages with 7 figures. To appear in "Virtual Astrophysical Jets" APSS, Kluwer Academic Publisher - Massaglia, Bodo, Rossi eds - in pres

    Maximizing the impact of malaria funding through allocative efficiency: using the right interventions in the right locations.

    Full text link
    BACKGROUND: The high burden of malaria and limited funding means there is a necessity to maximize the allocative efficiency of malaria control programmes. Quantitative tools are urgently needed to guide budget allocation decisions. METHODS: A geospatial epidemic model was coupled with costing data and an optimization algorithm to estimate the optimal allocation of budgeted and projected funds across all malaria intervention approaches. Interventions included long-lasting insecticide-treated nets (LLINs), indoor residual spraying (IRS), intermittent presumptive treatment during pregnancy (IPTp), seasonal mass chemoprevention in children (SMC), larval source management (LSM), mass drug administration (MDA), and behavioural change communication (BCC). The model was applied to six geopolitical regions of Nigeria in isolation and also the nation as a whole to minimize incidence and malaria-attributable mortality. RESULTS: Allocative efficiency gains could avert approximately 84,000 deaths or 15.7 million cases of malaria in Nigeria over 5 years. With an additional US$300 million available, approximately 134,000 deaths or 37.3 million cases of malaria could be prevented over 5 years. Priority funding should go to LLINs, IPTp and BCC programmes, and SMC should be expanded in seasonal areas. To minimize mortality, treatment expansion is critical and prioritized over some LLIN funding, while to minimize incidence, LLIN funding remained a priority. For areas with lower rainfall, LSM is prioritized over IRS but MDA is not recommended unless all other programmes are established. CONCLUSIONS: Substantial reductions in malaria morbidity and mortality can be made by optimal targeting of investments to the right malaria interventions in the right areas

    Gene Function Classification Using Bayesian Models with Hierarchy-Based Priors

    Get PDF
    We investigate the application of hierarchical classification schemes to the annotation of gene function based on several characteristics of protein sequences including phylogenic descriptors, sequence based attributes, and predicted secondary structure. We discuss three Bayesian models and compare their performance in terms of predictive accuracy. These models are the ordinary multinomial logit (MNL) model, a hierarchical model based on a set of nested MNL models, and a MNL model with a prior that introduces correlations between the parameters for classes that are nearby in the hierarchy. We also provide a new scheme for combining different sources of information. We use these models to predict the functional class of Open Reading Frames (ORFs) from the E. coli genome. The results from all three models show substantial improvement over previous methods, which were based on the C5 algorithm. The MNL model using a prior based on the hierarchy outperforms both the non-hierarchical MNL model and the nested MNL model. In contrast to previous attempts at combining these sources of information, our approach results in a higher accuracy rate when compared to models that use each data source alone. Together, these results show that gene function can be predicted with higher accuracy than previously achieved, using Bayesian models that incorporate suitable prior information

    Surveillance strategies for Classical Swine Fever in wild boar – a comprehensive evaluation study to ensure powerful surveillance

    Get PDF
    Surveillance of Classical Swine Fever (CSF) should not only focus on livestock, but must also include wild boar. To prevent disease transmission into commercial pig herds, it is therefore vital to have knowledge about the disease status in wild boar. In the present study, we performed a comprehensive evaluation of alternative surveillance strategies for Classical Swine Fever (CSF) in wild boar and compared them with the currently implemented conventional approach. The evaluation protocol was designed using the EVA tool, a decision support tool to help in the development of an economic and epidemiological evaluation protocol for surveillance. To evaluate the effectiveness of the surveillance strategies, we investigated their sensitivity and timeliness. Acceptability was analysed and finally, the cost-effectiveness of the surveillance strategies was determined. We developed 69 surveillance strategies for comparative evaluation between the existing approach and the novel proposed strategies. Sampling only within sub-adults resulted in a better acceptability and timeliness than the currently implemented strategy. Strategies that were completely based on passive surveillance performance did not achieve the desired detection probability of 95%. In conclusion, the results of the study suggest that risk-based approaches can be an option to design more effective CSF surveillance strategies in wild boar

    Taxonomy, biostratigraphy, and phylogeny of Oligocene and lower Miocene Dentoglobigerina and Globoquadrina

    Get PDF
    The taxonomy, phylogeny, and biostratigraphy of Oligocene and lower Miocene Dentoglobigerina and Globoquadrina are reviewed. Because of the discovery of spine holes in various species assigned to these genera, the entire group is now considered to have been fully or sparsely spinose in life and hence part of Family Globigerinidae. One new species, Dentoglobigerina eotripartita Pearson, Wade, and Olsson n. sp., is named. Dentoglobigerina includes forms with and without umbilical teeth and species for which the presence or absence of a tooth is a variable feature. A significant finding has been the triple synonymy of Globigerina tripartita Koch, Globigerina rohri Bolli, and Globoquadrina dehiscens praedehiscens Blow, which greatly simplifies part of the taxonomy. The genus Globoquadrina is restricted to its type species, Globigerina dehiscens Chapman and others. The following species from the time interval of interest are regarded as valid: Dentoglobigerina altispira (Cushman and Jarvis), Dentoglobigerina baroemoenensis (LeRoy), Dentoglobigerina binaiensis (Koch), Dentoglobigerina eotripartita Pearson, Wade, and Olsson n. sp., Dentoglobigerina galavisi (BermĂşdez), Dentoglobigerina globosa (Bolli), Dentoglobigerina globularis (BermĂşdez), Dentoglobigerina juxtabinaiensis Fox and Wade, Dentoglobigerina larmeui (Akers), Dentoglobigerina prasaepis (Blow), Dentoglobigerina pseudovenezuelana (Blow and Banner), Dentoglobigerina sellii (Borsetti), Dentoglobigerina taci Pearson and Wade, Dentoglobigerina tapuriensis (Blow and Banner), Dentoglobigerina tripartita (Koch), Dentoglobigerina venezuelana (Hedberg), and Globoquadrina dehiscens (Chapman, Parr, and Collins). The genus Dentoglobigerina also comprises other Neogene/Quaternary species not listed, including the living species Dentoglobigerina cf. conglomerata (Schwager)
    • …
    corecore