262 research outputs found

    Thalamocortical Connectivity Correlates with Phenotypic Variability in Dystonia

    Get PDF
    Dystonia is a brain disorder characterized by abnormal involuntary movements without defining neuropathological changes. The disease is often inherited as an autosomal-dominant trait with incomplete penetrance. Individuals with dystonia, whether inherited or sporadic, exhibit striking phenotypic variability, with marked differences in the somatic distribution and severity of clinical manifestations. In the current study, we used magnetic resonance diffusion tensor imaging to identify microstructural changes associated with specific limb manifestations. Functional MRI was used to localize specific limb regions within the somatosensory cortex. Microstructural integrity was preserved when assessed in subrolandic white matter regions somatotopically related to the clinically involved limbs, but was reduced in regions linked to clinically uninvolved (asymptomatic) body areas. Clinical manifestations were greatest in subjects with relatively intact microstructure in somatotopically relevant white matter regions. Tractography revealed significant phenotype-related differences in the visualized thalamocortical tracts while corticostriatal and corticospinal pathways did not differ between groups. Cerebellothalamic microstructural abnormalities were also seen in the dystonia subjects, but these changes were associated with genotype, rather than with phenotypic variation. The findings suggest that the thalamocortical motor system is a major determinant of dystonia phenotype. This pathway may represent a novel therapeutic target for individuals with refractory limb dystonia

    Navigating tensions in inclusive conservation: Learning from the Utrechtse Heuvelrug National Park in the Netherlands

    Get PDF
    Inclusive conservation is promoted as a means to integrate stakeholders in nature, conservation. Despite several studies recognizing that inclusive conservation of protected areas may be challenging and requires explicitly addressing potential tensions between stakeholders, little research has unpacked how these tensions manifest in specific contexts. This paper aims to explore possible approaches for navigating tensions to improve the facilitation of an inclusive conservation approach in the Utrechtse Heuvelrug National Park in the Netherlands. We conducted 18 semistructured interviews with stakeholders such as public and private landowners and, municipal and provincial governments in the national park. Results reveal a longer history of collaboration which still fails to address the root of the tensions. The experiences show that compromising or consensus building amongst stakeholders alone is not sufficient for achieving inclusive conservation. Guidance and clear goals set by policy, as well as sufficient investments in capacity and trust building are recommended to avoid inaction. Furthermore, we found that tensions are inextricably linked to different dimensions of power, such as discursive and structural power. While considering power in inclusive conservation can provide a realistic perspective we also, acknowledge that equalizing power is not the silver bullet underpinning this conservation approach.</p

    Editor's Choice - Re-interventions After Repair of Ruptured Abdominal Aortic Aneurysm: A Report From the IMPROVE Randomised Trial.

    Get PDF
    OBJECTIVE/BACKGROUND: The aim was to describe the re-interventions after endovascular and open repair of rupture, and investigate whether these were associated with aortic morphology. METHODS: In total, 502 patients from the IMPROVE randomised trial (ISRCTN48334791) with repair of rupture were followed-up for re-interventions for at least 3 years. Pre-operative aortic morphology was assessed in a core laboratory. Re-interventions were described by time (0-90 days, 3 months-3 years) as arterial or laparotomy related, respectively, and ranked for severity by surgeons and patients separately. Rare re-interventions to 1 year, were summarised across three ruptured abdominal aortic aneurysm trials (IMPROVE, AJAX, and ECAR) and odds ratios (OR) describing differences were pooled via meta-analysis. RESULTS: Re-interventions were most common in the first 90 days. Overall rates were 186 and 226 per 100 person years for the endovascular strategy and open repair groups, respectively (p = .20) but between 3 months and 3 years (mid-term) the rates had slowed to 9.5 and 6.0 re-interventions per 100 person years, respectively (p = .090) and about one third of these were for a life threatening condition. In this latter, mid-term period, 42 of 313 remaining patients (13%) required at least one re-intervention, most commonly for endoleak or other endograft complication after treatment by endovascular aneurysm repair (EVAR) (21 of 38 re-interventions), whereas distal aneurysms were the commonest reason (four of 23) for re-interventions after treatment by open repair. Arterial re-interventions within 3 years were associated with increasing common iliac artery diameter (OR 1.48, 95% confidence interval [CI] 0.13-0.93; p = .004). Amputation, rare but ranked as the worst re-intervention by patients, was less common in the first year after treatment with EVAR (OR 0.2, 95% CI 0.05-0.88) from meta-analysis of three trials. CONCLUSION: The rate of mid-term re-interventions after rupture is high, more than double that after elective EVAR and open repair, suggesting the need for bespoke surveillance protocols. Amputations are much less common in patients treated by EVAR than in those treated by open repair

    Predicting risk of rupture and rupture-preventing reinterventions following endovascular abdominal aortic aneurysm repair

    Get PDF
    BackgroundClinical and imaging surveillance practices following endovascular aneurysm repair (EVAR) for intact abdominal aortic aneurysm (AAA) vary considerably and compliance with recommended lifelong surveillance is poor. The aim of this study was to develop a dynamic prognostic model to enable stratification of patients at risk of future secondary aortic rupture or the need for intervention to prevent rupture (rupture-preventing reintervention) to enable the development of personalized surveillance intervals. MethodsBaseline data and repeat measurements of postoperative aneurysm sac diameter from the EVAR-1 and EVAR-2 trials were used to develop the model, with external validation in a cohort from a single-centre vascular database. Longitudinal mixed-effects models were fitted to trajectories of sac diameter, and model-predicted sac diameter and rate of growth were used in prognostic Cox proportional hazards models. ResultsSome 785 patients from the EVAR trials were included, of whom 155 (197 per cent) experienced at least one rupture or required a rupture-preventing reintervention during follow-up. An increased risk was associated with preoperative AAA size, rate of sac growth and the number of previously detected complications. A prognostic model using predicted sac growth alone had good discrimination at 2years (C-index 068), 3years (C-index 072) and 5years (C-index 075) after operation and had excellent external validation (C-index 076-079). More than 5years after operation, growth rates above 1mm/year had a sensitivity of over 80 per cent and specificity over 50 per cent in identifying events occurring within 2years. ConclusionSecondary sac growth is an important predictor of rupture or rupture-preventing reintervention to enable the development of personalized surveillance intervals. A dynamic prognostic model has the potential to tailor surveillance by identifying a large proportion of patients who may require less intensive follow-up. Potential to tailor surveillancePeer reviewe

    Meta-analysis of individual-patient data from EVAR-1, DREAM, OVER and ACE trials comparing outcomes of endovascular or open repair for abdominal aortic aneurysm over 5 years

    Get PDF
    Background: The erosion of the early mortality advantage of elective endovascular aneurysm repair (EVAR) compared with open repair of abdominal aortic aneurysm remains without a satisfactory explanation.Methods: An individual-patient data meta-analysis of four multicentre randomized trials of EVAR versus open repair was conducted to a prespecified analysis plan, reporting on mortality, aneurysm-related mortality and reintervention.Results: The analysis included 2783 patients, with 14 245 person-years of follow-up (median 5.5years). Early (0-6 months after randomization) mortality was lower in the EVAR groups (46 of 1393 versus 73 of 1390 deaths; pooled hazard ratio 0.61, 95 per cent c. i. 0.42 to 089; P = 0010), primarily because 30-day operative mortality was lower in the EVAR groups (16 deaths versus 40 for open repair; pooled odds ratio 040, 95 per cent c. i. 022 to 074). Later (within 3 years) the survival curves converged, remaining converged to 8 years. Beyond 3 years, aneurysm-related mortality was significantly higher in the EVAR groups (19 deaths versus 3 for open repair; pooled hazard ratio 516, 149 to 1789; P = 0010). Patients with moderate renal dysfunction or previous coronary artery disease had no early survival advantage under EVAR. Those with peripheral artery disease had lower mortality under open repair (39 deaths versus 62 for EVAR; P = 0022) in the period from 6 months to 4 years after randomization.Conclusion: The early survival advantage in the EVAR group, and its subsequent erosion, were confirmed. Over 5 years, patients of marginal fitness had no early survival advantage from EVAR compared with open repair. Aneurysm-related mortality and patients with low ankle : brachial pressure index contributed to the erosion of the early survival advantage for the EVAR group. Trial registration numbers: EVAR-1, ISRCTN55703451; DREAM(Dutch Randomized Endovascular Aneurysm Management), NCT00421330; ACE (Anevrysme de l'aorte abdominale, Chirurgie versus Endoprothsse), NCT00224718; OVER (Open Versus Endovascular Repair Trial for Abdominal Aortic Aneurysms), NCT00094575.</p

    The visual perception of natural motion: abnormal task-related neural activity in DYT1 dystonia

    Get PDF
    Although primary dystonia is defined by its characteristic motor manifestations, non-motor signs and symptoms have increasingly been recognized in this disorder. Recent neuroimaging studies have related the motor features of primary dystonia to connectivity changes in cerebello-thalamo-cortical pathways. It is not known, however, whether the non-motor manifestations of the disorder are associated with similar circuit abnormalities. To explore this possibility, we used functional magnetic resonance imaging to study primary dystonia and healthy volunteer subjects while they performed a motion perception task in which elliptical target trajectories were visually tracked on a computer screen. Prior functional magnetic resonance imaging studies of healthy subjects performing this task have revealed selective activation of motor regions during the perception of \u27natural\u27 versus \u27unnatural\u27 motion (defined respectively as trajectories with kinematic properties that either comply with or violate the two-thirds power law of motion). Several regions with significant connectivity changes in primary dystonia were situated in proximity to normal motion perception pathways, suggesting that abnormalities of these circuits may also be present in this disorder. To determine whether activation responses to natural versus unnatural motion in primary dystonia differ from normal, we used functional magnetic resonance imaging to study 10 DYT1 dystonia and 10 healthy control subjects at rest and during the perception of \u27natural\u27 and \u27unnatural\u27 motion. Both groups exhibited significant activation changes across perceptual conditions in the cerebellum, pons, and subthalamic nucleus. The two groups differed, however, in their responses to \u27natural\u27 versus \u27unnatural\u27 motion in these regions. In healthy subjects, regional activation was greater during the perception of natural (versus unnatural) motion (P \u3c 0.05). By contrast, in DYT1 dystonia subjects, activation was relatively greater during the perception of unnatural (versus natural) motion (P \u3c 0.01). To explore the microstructural basis for these functional changes, the regions with significant interaction effects (i.e. those with group differences in activation across perceptual conditions) were used as seeds for tractographic analysis of diffusion tensor imaging scans acquired in the same subjects. Fibre pathways specifically connecting each of the significant functional magnetic resonance imaging clusters to the cerebellum were reconstructed. Of the various reconstructed pathways that were analysed, the ponto-cerebellar projection alone differed between groups, with reduced fibre integrity in dystonia (P \u3c 0.001). In aggregate, the findings suggest that the normal pattern of brain activation in response to motion perception is disrupted in DYT1 dystonia. Thus, it is unlikely that the circuit changes that underlie this disorder are limited to primary sensorimotor pathways

    Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial

    Get PDF
    Objective To assess whether a strategy of endovascular repair (if aortic morphology is suitable, open repair if not) versus open repair reduces early mortality for patients with suspected ruptured abdominal aortic aneurysm. Design Randomised controlled trial. Setting 30 vascular centres (29 UK, 1 Canadian), 2009-13. Participants 613 eligible patients (480 men) with a clinical diagnosis of ruptured aneurysm. Interventions 316 patients were randomised to the endovascular strategy (275 confirmed ruptures, 174 anatomically suitable for endovascular repair) and 297 to open repair (261 confirmed ruptures). Main outcome measures 30 day mortality, with 24 hour and in-hospital mortality, costs, and time and place of discharge as secondary outcomes. Results 30 day mortality was 35.4% (112/316) in the endovascular strategy group and 37.4% (111/297) in the open repair group: odds ratio 0.92 (95% confidence interval 0.66 to 1.28; P=0.62); odds ratio after adjustment for age, sex, and Hardman index 0.94 (0.67 to 1.33). Women may benefit more than men (interaction test P=0.02) from the endovascular strategy: odds ratio 0.44 (0.22 to 0.91) versus 1.18 (0.80 to 1.75). 30 day mortality for patients with confirmed rupture was 36.4% (100/275) in the endovascular strategy group and 40.6% (106/261) in the open repair group (P=0.31). More patients in the endovascular strategy than in the open repair group were discharged directly to home (189/201 (94%) v 141/183 (77%); P<0.001). Average 30 day costs were similar between the randomised groups, with an incremental cost saving for the endovascular strategy versus open repair of £1186 (€1420; $1939) (95% confidence interval −£625 to £2997). Conclusions A strategy of endovascular repair was not associated with significant reduction in either 30 day mortality or cost. Longer term cost effectiveness evaluations are needed to assess the full effects of the endovascular strategy in both men and women

    Observations from the IMPROVE trial concerning the clinical care of patients with ruptured abdominal aortic aneurysm.

    Get PDF
    BACKGROUND: Single-centre series of the management of patients with ruptured abdominal aortic aneurysm (AAA) are usually too small to identify clinical factors that could improve patient outcomes. METHODS: IMPROVE is a pragmatic, multicentre randomized clinical trial in which eligible patients with a clinical diagnosis of ruptured aneurysm were allocated to a strategy of endovascular aneurysm repair (EVAR) or to open repair. The influences of time and manner of hospital presentation, fluid volume status, type of anaesthesia, type of endovascular repair and time to aneurysm repair on 30-day mortality were investigated according to a prespecified plan, for the subgroup of patients with a proven diagnosis of ruptured or symptomatic AAA. Adjustment was made for potential confounding factors. RESULTS: Some 558 of 613 randomized patients had a symptomatic or ruptured aneurysm: diagnostic accuracy was 91·0 per cent. Patients randomized outside routine working hours had higher operative mortality (adjusted odds ratio (OR) 1·47, 95 per cent confidence interval 1·00 to 2·17). Mortality rates after primary and secondary presentation were similar. Lowest systolic blood pressure was strongly and independently associated with 30-day mortality (51 per cent among those with pressure below 70 mmHg). Patients who received EVAR under local anaesthesia alone had greatly reduced 30-day mortality compared with those who had general anaesthesia (adjusted OR 0·27, 0·10 to 0·70). CONCLUSION: These findings suggest that the outcome of ruptured AAA might be improved by wider use of local anaesthesia for EVAR and that a minimum blood pressure of 70 mmHg is too low a threshold for permissive hypotension

    Regional brain metabolism in a murine systemic lupus erythematosus model

    Get PDF
    Systemic lupus erythematosus (SLE) is characterized by multiorgan inflammation, neuropsychiatric disorders (NPSLE), and antinuclear antibodies. We previously identified a subset of anti-DNA antibodies (DNRAb) cross-reactive with the N-methyl-D-aspartate receptor, present in 30% to 40% of patients, able to enhance excitatory post-synaptic potentials and trigger neuronal apoptosis. DNRAb + mice exhibit memory impairment or altered fear response, depending on whether the antibody penetrates the hippocampus or amygdala. Here, we used 18F-fluorodeoxyglucose (FDG) microPET to plot changes in brain metabolism after regional blood-brain barrier (BBB) breach. In DNRAb + mice, metabolism declined at the site of BBB breach in the first 2 weeks and increased over the next 2 weeks. In contrast, DNRAb mice exhibited metabolic increases in these regions over the 4 weeks after the insult. Memory impairment was present in DNRAb + animals with hippocampal BBB breach and altered fear conditioning in DNRAb + mice with amygdala BBB breach. In DNRAb + mice, we observed an inverse relationship between neuron number and regional metabolism, while a positive correlation was observed in DNRAb mice. These findings suggest that local metabolic alterations in this model take place through different mechanisms with distinct time courses, with important implications for the interpretation of imaging data in SLE subjects

    Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial.

    Get PDF
    OBJECTIVE: To assess whether a strategy of endovascular repair (if aortic morphology is suitable, open repair if not) versus open repair reduces early mortality for patients with suspected ruptured abdominal aortic aneurysm. DESIGN: Randomised controlled trial. SETTING: 30 vascular centres (29 UK, 1 Canadian), 2009-13. PARTICIPANTS: 613 eligible patients (480 men) with a clinical diagnosis of ruptured aneurysm. INTERVENTIONS: 316 patients were randomised to the endovascular strategy (275 confirmed ruptures, 174 anatomically suitable for endovascular repair) and 297 to open repair (261 confirmed ruptures). MAIN OUTCOME MEASURES: 30 day mortality, with 24 hour and in-hospital mortality, costs, and time and place of discharge as secondary outcomes. RESULTS: 30 day mortality was 35.4% (112/316) in the endovascular strategy group and 37.4% (111/297) in the open repair group: odds ratio 0.92 (95% confidence interval 0.66 to 1.28; P=0.62); odds ratio after adjustment for age, sex, and Hardman index 0.94 (0.67 to 1.33). Women may benefit more than men (interaction test P=0.02) from the endovascular strategy: odds ratio 0.44 (0.22 to 0.91) versus 1.18 (0.80 to 1.75). 30 day mortality for patients with confirmed rupture was 36.4% (100/275) in the endovascular strategy group and 40.6% (106/261) in the open repair group (P=0.31). More patients in the endovascular strategy than in the open repair group were discharged directly to home (189/201 (94%) v 141/183 (77%); P<0.001). Average 30 day costs were similar between the randomised groups, with an incremental cost saving for the endovascular strategy versus open repair of £1186 (€1420; $1939) (95% confidence interval -£625 to £2997). CONCLUSIONS: A strategy of endovascular repair was not associated with significant reduction in either 30 day mortality or cost. Longer term cost effectiveness evaluations are needed to assess the full effects of the endovascular strategy in both men and women. TRIAL REGISTRATION: Current Controlled Trials ISRCTN48334791
    • …
    corecore