1,240 research outputs found
The Evolution of Life History Traits and Their Thermal Plasticity in Daphnia
Few studies have explored the relative strength of ecogeographic versus lineage-specific effects on a global scale, particularly for poikilotherms, those organisms whose internal temperature varies with their environment. Here, we compile a global dataset of life history traits in Daphnia, at the species-and population-level, and use those data to parse the relative influences of lineage-specific effects and climate. We also compare the thermal response (plasticity) of life history traits and their dependence on climate, temperature, precipitation, and latitude. We found that the mode of evolution for life history traits varies but that the thermal response of life history traits most often follows a random walk model of evolution. We conclude that life history trait evolution in Daphnia is not strongly species-specific but is ecogeographically distinct, suggesting that life history evolution should be understood at the population level for Daphnia and possibly for other poikilotherms
Warming Overcomes Dispersal-Limitation to Promote Non-native Expansion in Lake Baikal
Non-native species and climate change pose serious threats to global biodiversity. However, the roles of climate, dispersal, and competition are difficult to disentangle in heterogeneous landscapes. We combine empirical data and theory to examine how these forces influence the spread of non-native species in Lake Baikal. We analyze the potential for Daphnia longispina to establish in Lake Baikal, potentially threatening an endemic, cryophillic copepod Epischurella baikalensis. We collected field samples to establish current community composition and compared them to model predictions informed by flow rates, present-day temperatures, and temperature projections. Our data and model agree that expansion is currently limited by dispersal. However, projected increases in temperature reverse this effect, allowing D. longispina to establish in Lake Baikal’s main basin. A strong negative impact emerges from the interaction between climate change and dispersal, outweighing their independent effects. Climate, dispersal, and competition have complex, interactive effects on expansion with important implications for global biodiversity
Restricted Diffusion of Pus in the Subarachnoid Space: MRSA Meningo-Vasculitis and Progressive Brainstem Ischemic Strokes – A Case Report
Extra-axial restriction on diffusion weighted imaging (DWI) is an unusual finding on brain magnetic resonance imaging (MRI). Intra-axial restriction on DWI, however, is common, and can represent brain parenchymal infarction, tumor, abscess, or toxic-metabolic process. The infrequency of extra-axial DWI restriction and the paucity of clinico-pathological correlation in the literature limit its differential diagnosis. Scant case reports suggest that extra-axial DWI restriction could be a lymphoma, neurenteric cyst, or, in one patient, subdural empyema [1,2,3]. We postulate that pus formation must be excluded first, because it can provoke an aggressive meningo-vasculitis with rapidly fatal, intra-axial infarctions. Our patient was a 45-year-old man, presenting to our hospital with left facial droop and right (contralateral) arm and leg weakness. Initial MRI revealed DWI restriction in the left lateral pons, consistent with a classic Millard-Gubler stroke. Also noted was a subtle, extra-axial area of curvilinear diffusion restriction in the left cerebellar-pontine angle's subarachnoid space. Days later, the patient had a headache, and repeat MRI revealed extension of the two DWI lesions – both the intra-axial pontine infarction and the extra-axial area of restricted diffusion in the subarachnoid space. The patient became comatose, a third MRI revealed more extensive DWI restrictions, and he expired despite aggressive care. Autopsy revealed massive brainstem infarcts, a thick lymphoplasmacytic infiltrate, copious Gram-Positive cocci (likely MRSA) and arteries partially occluded with fibrointimal proliferation. This emphasizes the concept that extra-axial DWI restriction can represent pus development in the subarachnoid space – a radiographic marker to identify a patient at risk for demise due to septic, meningo-vasculitic infarctions
Post-traumatic stress disorder symptoms and pain intensity in persons with spinal cord injury
Study design Cross-sectional. Objectives To examine the association between post-traumatic stress disorder (PTSD) symptoms and pain intensity, taking symptoms of anxiety and depression into account within persons with spinal cord injury (SCI). Setting Persons with SCI, who visited a Dutch rehabilitation centre between 2005 and 2010, were invited to complete a survey. Methods PTSD symptoms were measured with the Trauma Screening Questionnaire (TSQ), pain intensity with an 11-point Numerical Rating Scale (NRS), and symptoms of anxiety and depression with the Hospital Anxiety and Depression Scale (HADS). To determine associations between PTSD symptoms and pain intensity, linear regression analyses were performed. Confounding variables representing anxiety and depression were added to the final model. Results In total, 175 participants (55.8% traumatic, 29.1% complete) were included (response rate of 31.7%). Of them, 11.4% had clinically relevant symptoms of probable PTSD (TSQ score >= 6) 69.8% experienced moderate to severe pain levels (NRS >= 4), 14.9% had symptoms of anxiety and 20.8% symptoms of depression (HADS scores >= 11). Levels of PTSD symptoms were strongly associated with symptoms of anxiety (0.54) and depression (0.49). Bivariate analyses showed a moderate significant association (0.30) between PTSD symptoms and pain intensity. This association became small (0.10) when anxiety and depression comorbidity were factored into the final regression model. Conclusions No independent association between PTSD symptoms and pain intensity was shown when adjusted for anxiety and depression. Results of this study suggest the usefulness of screening for PTSD in persons with SCI (regardless of injury cause or type/level) who score high on symptoms of anxiety/depression
Identification of Leishmania major UDP-Sugar Pyrophosphorylase Inhibitors Using Biosensor-Based Small Molecule Fragment Library Screening
Leishmaniasis is a neglected disease that is caused by different species of the protozoan parasite Leishmania, and it currently affects 12 million people worldwide. The antileishmanial therapeutic arsenal remains very limited in number and efficacy, and there is no vaccine for this parasitic disease. One pathway that has been genetically validated as an antileishmanial drug target is the biosynthesis of uridine diphosphate-glucose (UDP-Glc), and its direct derivative UDP-galactose (UDP-Gal). De novo biosynthesis of these two nucleotide sugars is controlled by the specific UDP-glucose pyrophosphorylase (UGP). Leishmania parasites additionally express a UDP-sugar pyrophosphorylase (USP) responsible for monosaccharides salvage that is able to generate both UDP-Gal and UDP-Glc. The inactivation of the two parasite pyrophosphorylases UGP and USP, results in parasite death. The present study reports on the identification of structurally diverse scaffolds for the development of USP inhibitors by fragment library screening. Based on this screening, we selected a small set of commercially available compounds, and identified molecules that inhibit both Leishmania major USP and UGP, with a half-maximal inhibitory concentration in the 100 µM range. The inhibitors were predicted to bind at allosteric regulation sites, which were validated by mutagenesis studies. This study sets the stage for the development of potent USP inhibitors
Carers’ responses to shifting identity in dementia in Iris and Away From Her: cultivating stability or embracing change?
An emphasis on supporting and maintaining self-identity in people who have dementia for as long as possible has gone hand in hand with the revitalisation of dementia interventions, services and empowerment. However, recognition of the need for change, adaptation and personal growth is as necessary when living with dementia as at any other time in people's lives. Those who care for people with dementia must constantly navigate this tension between continuity and change within the context of memory loss, knowing when to respond by reinforcing the ‘self’ they have known over time, and when it may be better to respond by acknowledging the changes that have taken place in that ‘self’. The creative arts are avenues for the exploration of the caring relationship under these conditions, conveying the challenges and stimulating audiences to ask how they themselves might choose to respond in a similar situation. This article considers how the scenarios of two noted films, Iris (dir. Richard Eyre, 2001 UK)) and Away From Her (dir. Sarah Polley, 2006 Can), present the dilemmas of identity and caring. In both, a husband cares for a wife experiencing cognitive decline, but responds differently in each to her shifting needs and experience of identity. We argue that the two films reveal complementary and provocative perspectives on this situation. They offer no easy answers, but provide insights into the everyday decisions characteristic of caring for someone who has dementia
One-year outcomes after transcatheter insertion of an interatrial shunt device for the management of heart failure with preserved ejection fraction
Background—Heart failure with preserved ejection fraction has a complex pathophysiology and remains a therapeutic challenge. Elevated left atrial pressure, particularly during exercise, is a key contributor to morbidity and mortality. Preliminary analyses have demonstrated that a novel interatrial septal shunt device that allows shunting to reduce the left atrial pressure provides clinical and hemodynamic benefit at 6 months. Given the chronicity of heart failure with preserved ejection fraction, evidence of longer-term benefit is required.
Methods and Results—Patients (n=64) with left ventricular ejection fraction ≥40%, New York Heart Association class II–IV, elevated pulmonary capillary wedge pressure (≥15 mm Hg at rest or ≥25 mm Hg during supine bicycle exercise) participated in the open-label study of the interatrial septal shunt device. One year after interatrial septal shunt device implantation, there were sustained improvements in New York Heart Association class (P<0.001), quality of life (Minnesota Living with Heart Failure score, P<0.001), and 6-minute walk distance (P<0.01). Echocardiography showed a small, stable reduction in left ventricular end-diastolic volume index (P<0.001), with a concomitant small stable increase in the right ventricular end-diastolic volume index (P<0.001). Invasive hemodynamic studies performed in a subset of patients demonstrated a sustained reduction in the workload corrected exercise pulmonary capillary wedge pressure (P<0.01). Survival at 1 year was 95%, and there was no evidence of device-related complications.
Conclusions—These results provide evidence of safety and sustained clinical benefit in heart failure with preserved ejection fraction patients 1 year after interatrial septal shunt device implantation. Randomized, blinded studies are underway to confirm these observations
Self-Efficacy Predicts Personal and Family Adjustment Among Persons With Spinal Cord Injury or Acquired Brain Injury and Their Significant Others:A Dyadic Approach
Objectives: To investigate whether the combination of self-efficacy levels of individuals with spinal cord injury (SCI) or acquired brain injury (ABI) and their significant others, measured shortly after the start of inpatient rehabilitation, predict their personal and family adjustment 6 months after inpatient discharge. Design: Prospective longitudinal study. Setting: Twelve Dutch rehabilitation centers. Participants: Volunteer sample consisting of dyads (N=157) of adults with SCI or ABI who were admitted to inpatient rehabilitation and their adult significant others. Interventions: Not applicable. Main Outcome Measures: Self-efficacy (General Competence Scale) and personal and family adjustment (Hospital Anxiety and Depression Scale and McMaster Family Assessment Device General Functioning). Results: In 20 dyads, both individuals with SCI or ABI and their significant others showed low self-efficacy at baseline. In 67 dyads, both showed high self-efficacy. In the low-self-efficacy dyads, 61% of the individuals with SCI or ABI and 50% of the significant others showed symptoms of anxiety 6 months after discharge, vs 23% and 30%, respectively, in the high-self-efficacy dyads. In the low-self-efficacy dyads, 56% of individuals with SCI or ABI and 50% of the significant others reported symptoms of depression, vs 20% and 27%, respectively, in the high-self-efficacy dyads. Problematic family functioning was reported by 53% of the individuals with SCI or ABI and 42% of the significant others in the low-self-efficacy dyads, vs 4% and 12%, respectively, in the high-self-efficacy dyads. Multivariate analysis of variance analyses showed that the combination of levels of self-efficacy of individuals with SCI or ABI and their significant others at the start of inpatient rehabilitation predict personal (V=0.12; F-6,F-302=2.8; P=.010) and family adjustment (V=0.19; F-6,F-252=4.3; P Conclusions: Low-self-efficacy dyads appear to be more at risk for personal and family adjustment problems after discharge. Screening for self-efficacy may help healthcare professionals to identify and support families at risk for long-term adjustment problems. (C) 2020 by the American Congress of Rehabilitation Medicine. Published by Elsevier Inc
- …