903 resultados para Stressors


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Marsupial research, conservation, and management can benefit greatly from knowledge about glucocorticoid (GC) secretion patterns because GCs influence numerous aspects of physiology and play a crucial role in regulating an animal's response to stressors. Faecal glucocorticoid metabolites (FGM) offer a non-invasive tool for tracking changes in GCs over time. To date, there are relatively few validated assays for marsupials compared with other taxa, and those that have been published generally test only one assay. However, different assays can yield very different signals of adrenal activity. The goal of this study was to compare the performance of five different enzyme immunoassays (EIAs) for monitoring adrenocortical activity via FGM in 13 marsupial species. We monitored FGM response to two types of events: biological stressors (e.g., transport, novel environment) and pharmacological stimulation (ACTH injection). For each individual animal and assay, FGM peaks were identified using the iterative baseline approach. Performance of the EIAs for each species was evaluated by determining (1) the percent of individuals with a detectable peak 0.125-4.5days post-event, and (2) the biological sensitivity of the assay as measured by strength of the post-event response relative to baseline variability (Z-score). Assays were defined as successful if they detected a peak in at least 50% of the individuals and the mean species response had a Z⩾2. By this criterion, at least one assay was successful in 10 of the 13 species, but the best-performing assay varied among species, even those species that were closely related. Furthermore, the ability to confidently assess assay performance was influenced by the experimental protocols used. We discuss the implications of our findings for biological validation studies.

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 Findings from this phenomenological study revealed physical, psychological, emotional, social and spiritual benefits from accessing hospital gardens. The use and benefits gained through access to the gardens were context dependent, based on the needs and individual stressors faced by each user group.

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An ability to predict population dynamics of the amphipod Diporeia is important in understanding how energy pathways in the Lake Superior food web might be altered by disturbances to the ecosystem. Estimating growth rates for this prominent prey item for fish requires information on the physiological effects of changes to its environment. These effects have been investigated for Diporeia in other Great Lakes, but little is known about Lake Superior populations. The primary objective of this study is to obtain quantitative data for rates of Diporeia respiration and consumption that can be incorporated into a bioenergetics model for Lake Superior. Benthic communities in Lake Superior were sampled bimonthly from April through September during 2011 and 2012 to investigate spatial and temporal trends of Diporeia abundances as well as size class structures of the population. Additional samples of Diporeia were collected and kept alive in natural sediment for laboratory experiments. Respiration rates for Diporeia were measured by monitoring dissolved oxygen concentrations in microcosoms using microelectrodes. Additionally, a series of experiments to estimate consumption rates based on food availability were conducted using 14C-labeled algae (Selenastrum capricornutum). Amphipod population densities are highest between 30-110 m (slope) compared to 0-30 m (shelf) or >110 m (profundal) regions in Lake Superior. This heterogeneous distribution of Diporeia in Lake Superior is an important component to quantifying lake-wide biomass. Rates of oxygen consumption by Diporeia range from 32.0 to 44.7 mgO2*gDW-1*d-1, and do not vary significantly with body size per individual. The predicted consumption rate corresponding to average Lake Superior algal carbon fluxes was 0.08 ± SE mgC*gDW-1*d-1. Data on Lake Superior Diporeia biomass and bioenergetics found in this study can be incorporated in a model used to estimate the viability of this population under potential future environmental stressors.

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The study analyzed hydro-climatic and land use sensitivities of stormwater runoff and quality in the complex coastal urban watershed of Miami River Basin, Florida by developing a Storm Water Management Model (EPA SWMM 5). Regression-based empirical models were also developed to explain stream water quality in relation to internal (land uses and hydrology) and external (upstream contribution, seawater) sources and drivers in six highly urbanized canal basins of Southeast Florida. Stormwater runoff and quality were most sensitive to rainfall, imperviousness, and conversion of open lands/parks to residential, commercial and industrial areas. In-stream dissolved oxygen and total phosphorus in the watersheds were dictated by internal stressors while external stressors were dominant for total nitrogen and specific conductance. The research findings and tools will be useful for proactive monitoring and management of storm runoff and urban stream water quality under the changing climate and environment in South Florida and around the world.

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Prior resilience research typically focuses on either the individual or the organisational level of analysis, emphasises resilience in relation to day-to-day stressors rather than extreme events and is empirically under-developed. In response, our study inductively theorises about the relationships between individual and organisational resilience, drawing upon a large-scale study of resilience work in UK and French organisations. Our first-hand accounts of resilience work reveal the micro-processes involved in producing resilient organisations, and highlight the challenges experienced in doing resilience work in large organisations. We show that these micro-processes have significant implications for resilience at both individual and organisational levels, and draw implications for how HRM interventions can help to promote individual, and thus organisational, resilience.

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Outbreaks of fibropapillomatosis (FP), a neoplastic infectious disease of marine turtles, have occurred worldwide since the 1980s. Its most likely aetiological agent is a virus, but disease expression depends on external factors, typically associated with altered environments. The scarcity of robust long-term data on disease prevalence has limited interpretations on the impacts of FP on turtle populations. Here we model the dynamics of FP at 2 green turtle foraging aggregations in Puerto Rico, through 18 yr of capture-mark-recapture data (1997−2014). We observed spatiotemporal variation in FP prevalence, potentially modulated via individual site-fidelity. FP ex pression was residency dependent, and FP-free individuals developed tumours after 1.8 ± 0.8 yr (mean ± SD) in the infected area. Recovery from the disease was likely, with complete tumour regression occurring in 2.7 ± 0.7 yr (mean ± SD). FP does not currently seem to be a major threat to marine turtle populations; however, disease prevalence is yet unknown in many areas. Systematic monitoring is highly advisable as human-induced stressors can lead to deviations in host− pathogen relationships and disease virulence. Finally, data collection should be standardized for a global assessment of FP dynamics and impacts.

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TET2 is a tumor suppressor gene that has been implicated in the epigenetic regulation of gene expression. Inactivating TET2 mutations are common in MDS. These mutations may contribute to early clonal dominance and myeloid transformation, although the exact mechanisms remain to be elucidated. Common to the environment of MDS are elevations in cytokines, such as TNFα and IFN-γ. It was hypothesized that inflammatory cytokines TNF-α and IFN-γ may promote clonal expansion of TET2 mutant progenitors. Adult (10-14 weeks-old) Tet2 wild type (+/+) and Tet2 mutant (-/-) C57BL/6 mice strains were chosen as a model system. Lineage negative cells (Lin-), enriched for hematopoietic stem and progenitor cells, were isolated from Tet2 +/+ and -/- bone marrow and cultured in the absence or presence of varying concentrations of TNFα or IFN-γ in methylcellulose colony formation assays and long term cell culture assays, over a period of 12 and 30 days respectively, and their colony growth, cell count, immunophenotype and resistance to apoptosis were examined. Where indicated, serial re-plating was performed. Expression of apoptotic regulators was assessed by qRT-PCR. In the triplicate experiments, starting with equal densities of Tet2 +/+ and -/- Lin- cells, Tet2 -/- Lin- cells displayed increased resistance to cytokine-induced growth suppression and superior colony forming ability over +/+ in the serial re-plating assays under stress of increasing TNFα or IFN γ. Tet2 -/- progenitors also displayed a lower apoptotic index compared to +/+ under stress of increasing TNFα, suggesting increased resistance to TNFα induced apoptosis. Transcriptional data showed low expression of Tnfr1, Fas and caspase 8, as well as a high expression of Bcl-2 and Iap1 in Tet2 -/- compared to +/+ under stress of TNFα. Tet2-/- also showed increased basal expression of endogenous TNFα mRNA compared to +/+. In the human colony growth assay, the clonal growth of TET2 mutant CFU-GM progenitors was enhanced at low TNFα concentrations. Conclusion: Mutations that promote resistance to environmental stem cell stressors are a known mechanism of clonal selection in aplastic anaemia and JAK2-mutant MPN and our findings suggest that this mechanism may be critical to clonal selection and dominance in MDS.

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The diaphragm is the primary inspiratory pump muscle of breathing. Notwithstanding its critical role in pulmonary ventilation, the diaphragm like other striated muscles is malleable in response to physiological and pathophysiological stressors, with potential implications for the maintenance of respiratory homeostasis. This review considers hypoxic adaptation of the diaphragm muscle, with a focus on functional, structural, and metabolic remodeling relevant to conditions such as high altitude and chronic respiratory disease. On the basis of emerging data in animal models, we posit that hypoxia is a significant driver of respiratory muscle plasticity, with evidence suggestive of both compensatory and deleterious adaptations in conditions of sustained exposure to low oxygen. Cellular strategies driving diaphragm remodeling during exposure to sustained hypoxia appear to confer hypoxic tolerance at the expense of peak force-generating capacity, a key functional parameter that correlates with patient morbidity and mortality. Changes include, but are not limited to: redox-dependent activation of hypoxia-inducible factor (HIF) and MAP kinases; time-dependent carbonylation of key metabolic and functional proteins; decreased mitochondrial respiration; activation of atrophic signaling and increased proteolysis; and altered functional performance. Diaphragm muscle weakness may be a signature effect of sustained hypoxic exposure. We discuss the putative role of reactive oxygen species as mediators of both advantageous and disadvantageous adaptations of diaphragm muscle to sustained hypoxia, and the role of antioxidants in mitigating adverse effects of chronic hypoxic stress on respiratory muscle function.

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As the physiological impact of chronic stress is difficult to study in humans, naturalistic stressors are invaluable sources of information in this area. This review systematically evaluates the research literature examining biomarkers of chronic stress, including neurocognition, in informal dementia caregivers. We identified 151 papers for inclusion in the final review, including papers examining differences between caregivers and controls as well as interventions aimed at counteracting the biological burden of chronic caregiving stress. Results indicate that cortisol was increased in caregivers in a majority of studies examining this biomarker. There was mixed evidence for differences in epinephrine, norepinephrine and other cardiovascular markers. There was a high level of heterogeneity in immune system measures. Caregivers performed more poorly on attention and executive functioning tests. There was mixed evidence for memory performance. Interventions to reduce stress improved cognition but had mixed effects on cortisol. Risk of bias was generally low to moderate. Given the rising need for family caregivers worldwide, the implications of these findings can no longer be neglected.

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Background: Maritime pilotage is a demanding occupation where pilots are required to perform complex procedures in sometimes unfamiliar working environments. These psychological stressors, in addition tothe physical demands associated with the role (e.g., reduced sleep, boarding, and departing vessels), may over time have a damaging effect on pilots’ physical and mental health. Therefore the aim of this paper was to systematically review the existing literature on maritime pilots’ health and well-being.Materials and methods: The databases academic search complete, MEDLINE and MEDLINE complete, PsycINFO, PsycARTICLES, PubMed, and ScienceDirect were searched from the earliest available record until 1 May 2015. From an initial pool of 167 manuscripts retrieved, only 18 were peer-reviewed original research and discussed topics associated with maritime pilots’ health and well-being.Results: In total, 29 factors associated with maritime pilot health and well-being were identified. These were loosely categorised into physical (n = 14), psychosocial (n = 8), and workplace issues (n = 7). The most commonly investigated factors were blood pressure or heart rate, sleep or fatigue, smoking and alcohol consumption, perceived stress, and shift duration or cycle. Conclusions: Findings from the review suggest that the prevention of cardiovascular diseases and associated cardio-metabolic risk factors seems to be of paramount importance, with ample evidence indicating that modern-day pilots present as being overweight or obese. What remains unknown is whether these physical factors are associated with variations in psychosocial functioning. Therefore, it is recommended that future pilotage investigations adopt a multidisciplinary approach to better quantify the impact of maritimepilotage on long-term health and well-being.

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OBJECTIVES: Previous research suggests that psychosocial job stressors may be plausible risk factors for suicide. This study assessed the relationship between psychosocial job stressors and suicide mortality across the Australian population. METHODS: We developed a job exposure matrix to objectively measure job stressors across the working population. Suicide data came from a nationwide coronial register. Living controls were selected from a nationally representative cohort study. Incidence density sampling was used to ensure that controls were sampled at the time of death of each case. The period of observation for both cases and controls was 2001 to 2012. We used multilevel logistic regression to assess the odds of suicide in relation to 2 psychosocial job stressors (job control and job demands), after matching for age, sex, and year of death/survey and adjusting for socioeconomic status. RESULTS: Across 9,010 cases and 14,007 matched controls, our results suggest that low job control (odds ratio [OR], 1.35; 95% confidence interval [CI], 1.26-1.44; p < .001) and high job demands (OR, 1.36; 95% CI, 1.26-1.46; p < .001) were associated with increased odds of male suicide after adjusting for socioeconomic status. High demands were associated with lower odds of female suicide (OR, 0.81; 95% CI, 0.72-0.92; p = .002). CONCLUSIONS: It seems that adverse experiences at work are a risk factor for male suicide while not being associated with an elevated risk among females. Future studies on job stressors and suicide are needed, both to further understand the biobehavioral mechanisms explaining the link between job stress and suicide, and to inform targeted prevention initiatives.

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At two natural volcanic seeps in Papua New Guinea, the partial pressure of carbon dioxide (pCO2) in the seawater is consistent with projections for 2100. Here, the cover of massive scleractinian corals Porites spp. is twice as high at elevated compared with ambient pCO2, while that of branching corals such as Acropora millepora is greater than twofold reduced. To assess the underlying mechanisms for such community shifts under long-term exposure to elevated pCO2, biochemical parameters related to tissue biomass, energy storage, pigmentation, cell protection, and cell damage were compared between Porites spp. and A. millepora from control (mean pHtotal = 8.1, pCO2 = 323 µatm) and CO2 seep sites (mean pHtotal = 7.8, pCO2 = 803 µatm) each at two reefs. In Porites spp., only one of the biochemical parameters investigated (the ratio of photoprotective to light-harvesting pigments) responded to pCO2, while tissue biomass, total lipids, total proteins, and some pigments differed between the two reefs, possibly reflecting differences in food availability. Furthermore, some fatty acids showed pCO2 –reef interactions. In A. millepora, most pigments investigated were reduced at elevated pCO2, while other parameters (e.g. tissue biomass, total proteins, total lipids, protein carbonyls, some fatty acids and pigments) differed between reefs or showed pCO2–reef interactions. Tissue biomass, total lipids, and cell-protective capacities were distinctly higher in Porites spp. than in A. millepora, indicating higher resistance to environmental stress in massive Porites. However, our data suggest that important biochemical measures remain relatively unaffected in these two coral species in response to elevated pCO2 up to 800 µatm, with most responses being smaller than differences between species and locations, and also when compared with responses to other environmental stressors such as ocean warming.

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Extensive research has examined the effects of social isolation in neonatal and adult animal populations, but few studies have examined the effect of social isolation in early adulthood. Animals reaching reproductive age often experience extensive social changes as they leave their natal site, and a social stressor like isolation may uniquely affect this age group. Furthermore, adolescence is a time when sex differences in behavior become more pronounced. As such, the effects of social stressors are likely to vary by sex. In this study, we used noninvasive methods to evaluate stress responses to social change in male and female subadult chickens (Gallus gallus). Half of the birds experienced regular sessions of social isolation over the course of 2 wk, while the other half were never isolated. Subsequently, all of the animals were exposed to a suite of three novel probes, including an open-field test. We monitored the birds’ behavioral (head movements) and physiological (fecal glucocorticoid metabolites, FGM) response to the tests. Our results indicate that, for subadult chickens, the effect of social isolation is sex dependent: Male FGM and behavioral responses did not change with subsequent experiences, in contrast to females. Females also exhibited more social reinstatement behavior compared to males. Our results are consistent with the expectations of differences between the sexes based on changes in the social environment due to sex-biased dispersal patterns. For both sexes, the FGM and behavioral responses varied independently, which highlights the necessity for multiple measures of stress in animal populations.

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El propósito de este estudio es realizar un estado del arte sobre estrés laboral entre los años 2005 y 2016 utilizando artículos publicados en las bases de datos Ebsco, Apa-Psychnet, Proquest, Psycodoc, Pubmed, Redalyc y Scielo las cuales están abaladas por la Universidad del Rosario. Se hallaron en total 2674 artículos utilizando 6 palabras claves como criterios de búsqueda los cuales fueron Estrés Laboral, Estrés ocupacional, Estrés en el Trabajo, Job Stress, Work Stress y Occupational Stress. El instrumento de recolección de información fue una ficha bibliográfica modificada la cual permitió sistematizar los datos de los artículos encontrados en diferentes dimensiones para así poder utilizar los artículos encontrados como unidades de análisis para la investigación. El análisis de los artículos arrojó una diferencia significativa entre el volumen de publicaciones hechas en español versus las hechas en inglés tanto de artículos empíricos como teóricos. También se encontraron indicadores que permiten ver como el estudio del estrés laboral ha aumentado desde el año 2012 hasta la actualidad, siendo este el lapso en el cual el 59% de los artículos han sido arbitrados y subidos a las diferentes bases de datos.

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Introduction The hospitalization of a child causes big changes in child and his family life. Parents often suffer from stress and anxiety. This can affect their relationship with the child. Because of the closeness to the parents, nurses have an important role in giving parents support so they can have more energy to support and take care of their children and in the inclusion of the family in the process of care Objectives: To define what family-centered care is, the needs of hospitalized children's parents and to identify the strategies and methods that the nurses use to give parental support adapted to the parent's needs and to identify the differences between parental support given by nurses in Belgium and Portugal. Methods and procedures The study exists out of two parts. First is an integrative review of literature. The search was performed using the databases MEDLINE, CINAHL , PubMed and Science Direct. 18 Articles were selected based on inclusion criteria. Second part is a focus group. The participants were pediatric nurses from Portugal and Belgium. Results family-centered care can be considered as a partnership between family and nurses. It has some general principles: information sharing, respect differences, negotiation and care in the context of the family. Parents have different needs: knowledge and communication, support, comfort, proximity and assurance. Parents cope with stress in different ways and nurses can support them while they are in the hospital. It is a nurse task to identify the stressors and know methods of emotional support, so she can protect the family structure. Nurses should always see the family as a path to the child, with whom the nurses should worry about taking care and meeting their needs. Conclusion Nurses should collect information which includes family relationships, cultural and religious habits and familiar dynamic. Parents need interpersonal emotional support. It is important for parents to be close to their children and take care of themselves. Nurses must create an environment where parents feel safe and have privacy. To create a therapeutic and professional relationship efficient communication is needed. Parents will experience less stress and anxiety.