Abundant molecular oxygen in the coma of comet 67P/Churyumov-Gerasimenko.

The composition of the neutral gas comas of most comets is dominated by H2O, CO and CO2, typically comprising as much as 95 per cent of the total gas density. In addition, cometary comas have been found to contain a rich array of other molecules, including sulfuric compounds and complex hydrocarbons. Molecular oxygen (O2), however, despite its detection on other icy bodies such as the moons of Jupiter and Saturn, has remained undetected in cometary comas. Here we report in situ measurement of O2 in the coma of comet 67P/Churyumov-Gerasimenko, with local abundances ranging from one per cent to ten per cent relative to H2O and with a mean value of 3.80 ± 0.85 per cent. Our observations indicate that the O2/H2O ratio is isotropic in the coma and does not change systematically with heliocentric distance. This suggests that primordial O2 was incorporated into the nucleus during the comet's formation, which is unexpected given the low upper limits from remote sensing observations. Current Solar System formation models do not predict conditions that would allow this to occur.

Perceived neuropsychological impairment inversely related to self-reported health and employment in multiple sclerosis.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) patients frequently report cognitive difficulties which impact daily functioning. The objective was to investigate the relationship between patient-reported cognitive impairment and depression, demographic and MS-related variables, and to clarify its impact on self-reported health measures and employment. METHOD: A large two-centre survey included the MS Neuropsychological Screening Questionnaire (MSNQ), the two-question screening tool for depression, vitality, health-related quality of life, the Health-Promoting Lifestyle Profile II and questions assessing social network satisfaction and employment status. RESULTS: Of the 751 respondents (median age 54 years, median Expanded Disability Status Scale 5, 66.2% female), two-thirds reported perceived neuropsychological impairment or depressive symptoms. Whilst depressive symptoms were related to higher MSNQ scores, the MSNQ poorly predicted depression. After correcting for confounders, higher MSNQ scores and depressive symptoms decreased vitality, health-related quality of life and health-promoting behaviours and increased the probability of being socially dissatisfied. In participants below retirement age, higher MSNQ and Expanded Disability Status Scale scores increased the probability of unemployment, whilst depression did not. CONCLUSION: The contribution of the MSNQ to self-reported health measures and its unique explanatory power regarding unemployment suggest that subjective cognitive complaints are connected to subtle, yet meaningful, neuropsychological dysfunction.

European Academy of Neurology and European Stroke Organization consensus statement and practical guidance for pre-hospital management of stroke.

BACKGROUND AND PURPOSE: The reduction of delay between onset and hospital arrival and adequate pre-hospital care of persons with acute stroke are important for improving the chances of a favourable outcome. The objective is to recommend evidence-based practices for the management of patients with suspected stroke in the pre-hospital setting. METHODS: The GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology was used to define the key clinical questions. An expert panel then reviewed the literature, established the quality of the evidence, and made recommendations. RESULTS: Despite very low quality of evidence educational campaigns to increase the awareness of immediately calling emergency medical services are strongly recommended. Moderate quality evidence was found to support strong recommendations for the training of emergency medical personnel in recognizing the symptoms of a stroke and in implementation of a pre-hospital 'code stroke' including highest priority dispatch, pre-hospital notification and rapid transfer to the closest 'stroke-ready' centre. Insufficient evidence was found to recommend a pre-hospital stroke scale to predict large vessel occlusion. Despite the very low quality of evidence, restoring normoxia in patients with hypoxia is recommended, and blood pressure lowering drugs and treating hyperglycaemia with insulin should be avoided. There is insufficient evidence to recommend the routine use of mobile stroke units delivering intravenous thrombolysis at the scene. Because only feasibility studies have been reported, no recommendations can be provided for pre-hospital telemedicine during ambulance transport. CONCLUSIONS: These guidelines inform on the contemporary approach to patients with suspected stroke in the pre-hospital setting. Further studies, preferably randomized controlled trials, are required to examine the impact of particular interventions on quality parameters and outcome.

A 10-year follow-up of the European multicenter trial of interferon ß-1b in secondary-progressive multiple sclerosis.

OBJECTIVES: To explore long-term effects of treatment and prognostic relevance of variables assessed at baseline and during the European secondary progressive multiple sclerosis (SPMS) trial of interferon beta 1b (IFNB-1b). METHODS: We assessed 362 patients (60% female; median age 41 years; Expanded Disability Status Scale (EDSS): 5.5; 51% randomized to IFNB-1b) for their EDSS and treatment history after 10 years. Non-parametric analysis of covariance (ANCOVA) and multivariate linear regression models were applied. RESULTS: Median EDSS was 6.0 at the end of the randomized controlled trial (RCT), in the IFNB-1b and placebo groups, and 7.0 in long-term follow-up patients (those receiving IFNB-1b in the RCT were 6.5 and those receiving placebo in the RCT were 7.0; p = 0.086). 24 patients (6.6%) were deceased. The EDSS at baseline and the EDSS change during the RCT were the most important predictors of the EDSS 10 years later (partial R(2): 0.47). The ability to predict changes in EDSS 10 years after the RCT was limited (R(2): 0.12). Magnetic resonance imaging (MRI) measures remained in the predictive models, but explained < 5% of the variability. CONCLUSIONS: The results from this analysis did not provide convincing evidence to support a favorable long-term outcome in those patients allocated IFNB-1b during the RCT, in our SPMS cohort. The progressive stage of the disease remains largely unpredictable by clinical and conventional MRI measures, so better prognostic markers are needed.

Self-reported levels of education and disability progression in multiple sclerosis.

OBJECTIVES: The purpose of our study is to investigate whether socioeconomic indicators such as education, financial concerns, employment, and living status are associated with disease progression in relapsing-onset and progressive-onset Multiple Sclerosis (MS). MATERIALS AND METHODS: We performed a cross-sectional survey among individuals with MS, registered by the Flemish MS society and included socioeconomic indicators. A Cox proportional hazard regression was performed with the time from MS onset and from birth to reach an ambulatory disability milestone corresponding to Expanded Disability Status Scale (EDSS) 6 (requiring a cane) as outcome measure, adjusted for gender, age at MS onset, and immunomodulatory treatment. RESULTS: Among the participants with relapsing-onset MS, subjects reporting education for more than 12 years had a reduced risk of reaching EDSS 6 compared to subjects reporting education for less than 12 years [HR from onset 0.68 (95% CI 0.49-0.95); HR from birth 0.71 (95% CI 0.51-0.99)]. In progressive-onset MS, longer education was associated with an increased hazard to reach EDSS 6 [HR from onset 1.25 (95% CI 0.91-1.70); HR from birth 1.39 (95% CI 1.02-1.90)]. CONCLUSIONS: Our study shows an association of self-reported levels of education with disability progression in MS, with the highest level being protective in relapsing-onset MS.

PLANET TOPERS: Planets, Tracing the Transfer, Origin, Preservation, and Evolution of their ReservoirS.

The Interuniversity Attraction Pole (IAP) 'PLANET TOPERS' (Planets: Tracing the Transfer, Origin, Preservation, and Evolution of their Reservoirs) addresses the fundamental understanding of the thermal and compositional evolution of the different reservoirs of planetary bodies (core, mantle, crust, atmosphere, hydrosphere, cryosphere, and space) considering interactions and feedback mechanisms. Here we present the first results after 2 years of project work.

The Symbol Digit Modalities Test as sentinel test for cognitive impairment in multiple sclerosis.

BACKGROUND AND PURPOSE: Cognitive impairment (CI) is found in about half of the multiple sclerosis (MS) population and is an important contributor to employment status and social functioning. CI is encountered in all disease stages and correlates only moderately with disease duration or Expanded Disability Status Scale scores. Most present neuropsychological test batteries are time-demanding and expensive. The Symbol Digit Modalities Test (SDMT) has been suggested as a screening tool for CI in MS. In this paper, we aim to assess the performance of the SDMT in predicting the outcome of an extensive battery. METHODS: Neuropsychological test results from 359 patients were assessed in a multidisciplinary MS center (National MS Center Melsbroek, Belgium). Using receiver operating characteristic curves, the performance of the SDMT in predicting the general cognitive outcome of the extensive Neuropsychological Screening Battery for MS (NSBMS) could be assessed. The performance of the SDMT was assessed for different levels of CI and compared with other cognitive tests. Finally, useful covariates were included in a logistic regression model. RESULTS: At a specificity of 0.60 a high sensitivity (0.91) was obtained indicating the potential of the SDMT as a sentinel test for CI in MS. The SDMT outperformed the individual tests included in the NSBMS, used as benchmark. As the logistic regression model did not result in a relevant improvement, it is concluded that most clinical variables influence both the SDMT and the NSBMS in a similar way. Excluding patients with possible practice effects, an optimal cutoff of 40 was found for the SDMT. CONCLUSION: As the SDMT is an easy, low-cost and fast test, this result may help to detect CI in everyday clinical practice.

Intracranial artery dissection.

The aim of this narrative review is to evaluate the pathogenesis, clinical features, diagnosis, treatment and prognosis of intracranial artery dissection (IAD). IAD is a rare and often unrecognized cause of stroke or subarachnoid haemorrhage (SAH), especially in young adults. Two types of IAD can be identified: a subintimal or subadventitial dissection. It is suggested that a subintimal dissection results in luminal stenosis, thromboembolism and subsequently cerebral ischaemia, whilst a subadventitial IAD could result in the formation of a pseudo-aneurysm and compression on brainstem or cranial nerves. Rupture of such a dissecting aneurysm causes SAH. The exact cause of IAD remains unknown but several factors are associated with its development. Diagnosis is based on clinical presentation and specific features seen on multimodal neuroimaging. The management of IAD depends on the clinical presentation. In the case of cerebral ischaemia, anticoagulants or antiplatelet agents are used, whilst in the case of SAH endovascular treatment is primarily advocated. Prognosis depends on clinical presentation. Presentation with SAH has a worse prognosis.

Performance on Paced Auditory Serial Addition Test and cerebral blood flow in multiple sclerosis.

BACKGROUND: To assess the relationship between performance on the Paced Auditory Serial Addition Test (PASAT) and both cerebral blood flow (CBF) and axonal metabolic integrity in normal appearing white matter (NAWM) of the centrum semiovale in patients with multiple sclerosis (MS). METHODS: Normal appearing white matter of the centrum semiovale was investigated with magnetic resonance (MR) imaging in 28 non-depressed individuals (18 patients with MS and 10 healthy controls). CBF was assessed with pseudo-continuous arterial spin labeling. N-acetylacetate/creatine (NAA/Cr) ratios (a metabolic axonal marker) were measured using (1) H-MR spectroscopy. CBF was also measured in frontoparietal cortices and cerebellar hemispheres. RESULTS: In subjects with MS, we found a positive correlation between performance on the PASAT and CBF to the left centrum semiovale (P = 0.008), but not with the NAA/Cr ratio. There were no correlations between PASAT scores and CBF to the right centrum semiovale, frontoparietal cortices, and cerebellar hemispheres. There was no correlation between PASAT scores and NAA/Cr ratios. CONCLUSIONS: Our preliminary results suggest that performance on the PASAT in subjects with MS correlates with CBF to the left centrum semiovale, which contains left frontoparietal white matter association tracts involved in information processing speed and working memory.

Female gender and reproductive factors affecting risk, relapses and progression in multiple sclerosis.

Multiple sclerosis (MS), a chronic inflammatory demyelina-ting and degenerative disease of the central nervous system, is a frequent cause of neurological disability in young adults. Female predominance has increased over the last decades. Although female gender carries a higher risk of developing relapsing remitting MS, being female and at child-bearing age also appears to provide some protection against cognitive decline and against progressive onset MS, an adverse predictive factor when considering long-term disability in MS. The risk of MS in women has been associated with an earlier age at menarche. In most studies, parity did not impact MS risk. However, the recently published association of higher parity and offspring number with a reduced risk of a first demyelinating event suggests a potential suppressive effect. Pregnancy in MS patients has been associated with a reduced relapse rate and a reduction of neurological symptoms, especially in the third trimester. Despite the increased relapse risk in the postpartum period, there is no indication of an adverse effect of childbirth on the long-term course of MS. Fertility treatment in MS has been associated with an increased relapse risk in the following 3-month period, especially when the procedure did not result in pregnancy and gonadotrophin-releasing hormone agonists were used. Altogether, there is substantial evidence to support a regulatory role of sex steroid hormones in MS. In the absence of correlations with single hormone blood levels, we can only speculate about the underlying mechanisms. In conclusion, the increased MS risk in women and the changes in relapse and progression risk in association with reproductive events suggest significant and complex interactions between immune, neuroendocrine and reproductive systems in MS.

Sunlight exposure and sun sensitivity associated with disability progression in multiple sclerosis.

BACKGROUND: Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS). OBJECTIVE: We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS. METHODS: We conducted a survey among persons with MS, registered by the Flemish MS society, Belgium, and stratified data according to relapsing-onset and progressive-onset MS. We used Kaplan-Meier survival and Cox proportional hazard regression analyses with time to Expanded Disability Status Scale (EDSS) 6 as outcome measure. Hazard ratios for the time from onset and from birth were calculated for the potentially predictive variables, adjusting for age at onset, gender and immunomodulatory treatment. RESULTS: 704 (51.3%) of the 1372 respondents had reached EDSS 6. In relapsing-onset MS, respondents reporting equal or higher levels of sun exposure than persons of the same age in the last 10 years had a decreased risk of reaching EDSS 6. In progressive-onset MS, increased sun sensitivity was associated with an increased hazard of reaching EDSS 6. CONCLUSION: The association of higher sun exposure with a better outcome in relapsing-onset MS may be explained by either a protective effect or reverse causality. Mechanisms underlying sun sensitivity might influence progression in progressive-onset MS.

Alcohol, coffee, fish, smoking and disease progression in multiple sclerosis.

BACKGROUND: Certain lifestyle factors might influence disease activity in multiple sclerosis (MS). OBJECTIVES: To investigate the consumption of alcoholic beverages, caffeinated drinks, fish and cigarette smoking in relation to disability progression in relapsing onset and progressive onset MS. METHODS: We conducted a cross-sectional survey amongst individuals with MS, registered by the Flemish MS society in Belgium. A time-to-event analysis and Cox proportional-hazard regression were performed with time to Expanded Disability Status Scale (EDSS) 6 (requiring a cane or support to walk for a distance of 100 m) as outcome measure. Hazard ratios for the time from onset and from birth were adjusted for age at onset, gender and immunomodulatory treatment. RESULTS: Data of 1372 persons with definite MS were collected. In the relapsing onset group, a decreased risk for reaching EDSS 6 was found in regular consumers of alcohol, wine, coffee and fish compared with those who never consumed these substances. Cigarette smoking was associated with an enhanced risk for reaching EDSS 6. In the progressive onset group, no association with the risk of reaching EDSS 6 was found, except for the type of fish. Preference for fatty fish was associated with an increased risk to reach EDSS 6, when lean fish was taken as the reference category. CONCLUSION: Consumption of alcoholic beverages, coffee and fish were inversely associated with progression of disability in relapsing onset MS, but not in progressive onset MS. These findings allow to support the hypothesis that different mechanisms might underlie progression of disability in relapsing and progressive onset MS.

Pre-stroke use of beta-blockers does not affect ischaemic stroke severity and outcome.

BACKGROUND AND PURPOSE: It is unclear whether pre-stroke beta-blockers use may influence stroke outcome. This study evaluates the independent effect of pre-stroke use of beta-blockers on ischaemic stroke severity and 3 months functional outcome. METHODS: Pre-stroke use of beta-blockers was investigated in 1375 ischaemic stroke patients who had been included in two placebo-controlled trials with lubeluzole. Stroke severity was assessed by either the National Institute of Health Stroke Scale (NIHSS) or the European Stroke Scale (ESS). A modified Rankin scale (mRS) score of >3 at 3 months was used as measure for the poor functional outcome. RESULTS: Two hundred and sixty four patients were on beta-blockers prior to stroke onset, and 105 patients continued treatment after their stroke. Pretreatment with beta-blockers did not influence baseline stroke severity. There was no difference in stroke severity between nonusers and those on either a selective beta(1)-blocker or a non-selective beta-blocker. The likelihood of a poor outcome at 3 months was not influenced by pre-stroke beta-blocker use or beta-blocker use before and continued after stroke onset. CONCLUSIONS: Pre-stroke use of beta-blockers does not appear to influence stroke severity and functional outcome at 3 months.

Identification and characterization of a new ensemble of cometary organic molecules.

In-situ study of comet 1P/Halley during its 1986 apparition revealed a surprising abundance of organic coma species. It remained unclear, whether or not these species originated from polymeric matter. Now, high-resolution mass-spectrometric data collected at comet 67P/Churyumov-Gerasimenko by ESA's Rosetta mission unveil the chemical structure of complex cometary organics. Here, we identify an ensemble of individual molecules with masses up to 140 Da while demonstrating inconsistency of the data with relevant amounts of polymeric matter. The ensemble has an average composition of C1H1.56O0.134N0.046S0.017, identical to meteoritic soluble organic matter, and includes a plethora of chain-based, cyclic, and aromatic hydrocarbons at an approximate ratio of 6:3:1. Its compositional and structural properties, except for the H/C ratio, resemble those of other Solar System reservoirs of organics-from organic material in the Saturnian ring rain to meteoritic soluble and insoluble organic matter -, which is compatible with a shared prestellar history.

Modifiable factors influencing relapses and disability in multiple sclerosis.

A growing body of literature indicates that the natural course of multiple sclerosis can be influenced by a number of factors. Strong evidence suggests that relapses can be triggered by infections, the postpartum period and stressful life events. Vaccinations against influenza, hepatitis B and tetanus appear to be safe. Surgery, general and epidural anaesthesia, and physical trauma are not associated with an increased risk of relapses. Factors that have been associated with a reduced relapse rate are pregnancy, exclusive breastfeeding, sunlight exposure and higher vitamin D levels. A number of medications, including hormonal fertility treatment, seem to be able to trigger relapses. Factors that may worsen progression of disability include stressful life events, radiotherapy to the head, low levels of physical activity and low vitamin D levels. Strong evidence suggests that smoking promotes disease progression, both clinically and on brain magnetic resonance imaging. There is no evidence for an increased progression of disability following childbirth in women with multiple sclerosis. Moderate alcohol intake and exercise might have a neuroprotective effect, but this needs to be confirmed.

tPA treatment for acute ischaemic stroke in patients with leukoaraiosis.

BACKGROUND AND PURPOSE: Whether leukoaraiosis on baseline CT is associated with an increased risk of symptomatic intracerebral haemorrhage (sICH) or poor outcome following tissue plasminogen activator (tPA) treatment for acute ischaemic stroke is still a matter of debate. OBJECTIVE: To investigate the relationship between the presence and severity of leukoaraiosis on baseline CT and the risk of sICH and functional outcome after tPA treatment for acute ischaemic stroke. METHODS: A single-center observational cohort study with a retrospective analysis on consecutive patients with ischaemic stroke treated with tPA in the period 2002-2008. Outcome measures were the occurrence of sICH and functional outcome at 3 months. RESULTS: Of the 400 patients, 24% had leukoaraiosis on their baseline CT. Eleven patients (11%) with leukoaraiosis versus thirteen (4%) patients without leukoaraiosis had a sICH [odds ratio (OR) 2.85 95%-CI 1.23-6.60, P = 0.02]. Multivariate analysis showed a non-significant trend towards an association of leukoaraiosis and sICH (OR 1.9, 95%-CI 0.78-4.68, P = 0.16). Leukoaraiosis was independently associated with poor functional outcome (OR 2.39, 95%-CI 1.21-4.72, P = 0.01). No difference was observed in the outcome measures amongst patients with moderate or severe leukoaraiosis. CONCLUSION: Our study demonstrates that patients treated with tPA and leukoaraiosis on their baseline CT are at greater risk of sICH and have a worse functional outcome compared to patients without leukoaraiosis. It is important to note that these results should not lead to exclusion of patients with leukoaraiosis for tPA treatment.

T2 lesions and rate of progression of disability in multiple sclerosis.

BACKGROUND AND PURPOSE: To assess the predictive value of T2 lesions on the rate of progression of disability in multiple sclerosis (MS). METHODS: We reanalyzed T2 lesion number and load on brain MRI scans, performed before 1997, of 186 MS patients, who were clinically followed. There were 90 patients with progressive MS (35 secondary progressive and 55 primary progressive), and 96 with relapsing remitting MS. The rate of progression of disability was measured by time to sustained progression of disability (defined as an increase in ≥ 1 point when the Expanded Disability Status Scale (EDSS) was 5.5 or less and an increase in EDSS of ≥ 0.5 point when the EDSS was 6.0 or higher), and by the Multiple Sclerosis Severity Score (MSSS). RESULTS: During follow-up (median 15 years, IQR 12-17 years), 94% of the patients with progressive MS and 50% of the patients with relapsing remitting MS had progression of disability. Higher T2 lesion number and load were modestly associated with a higher rate of disease progression on the MSSS and a shorter time to progression of disability in relapsing remitting MS, but not in progressive MS. CONCLUSIONS: Our findings indicate that the amount of T2 lesions has a small predictive value for progression of disability in relapsing remitting MS, but has no influence on the rate of progression in progressive MS.

Statin use and functional outcome after tissue plasminogen activator treatment in acute ischaemic stroke.

BACKGROUND: Preliminary findings suggest that statins may have a neuroprotective effect in patients with acute ischaemic stroke. This study investigated whether patients on prior statin therapy and treated with tissue plasminogen activator (tPA) for acute ischaemic stroke have a better functional outcome than statin-naïve patients. METHODS: In a prospective observational cohort study of 476 acute ischaemic stroke patients treated with tPA we investigated the relationship between prior statin use and functional outcome at 3 months, the occurrence of symptomatic intracerebral haemorrhage (SICH) and early in-hospital mortality. Ischaemic stroke subtypes were defined according to the TOAST classification. Favourable outcome was defined as a modified Rankin Scale score < or =2. RESULTS: Of the 476 patients included, 98 (20.6%) used a statin at stroke presentation. In the entire cohort, 45.6% of patients had a favourable outcome with no difference between patients with or without statin therapy (45.9 vs. 45.5%, p = 0.94). In the multivariable analysis, statin use was not associated with favourable outcome (OR = 1.1, 95% CI = 0.6-1.9, p = 0.87). In none of the different stroke subtype groups was statin use associated with favourable outcome. Finally, statin use was not an independent risk factor of SICH or of early in-hospital mortality. CONCLUSION: Prior statin therapy in patients with acute ischaemic stroke treated with tPA is not associated with a more favourable outcome, and this is independent of stroke subtype.

Parity and secondary progression in multiple sclerosis.

BACKGROUND: Pregnancy has a well-documented effect on relapses in multiple sclerosis (MS), whereas little is known about the impact of pregnancy and childbirth on the risk of secondary progression. OBJECTIVE: To investigate the association of parity and secondary progression in women with MS. METHODS: The association of the number of births and secondary progression was studied in a hospital-based cohort of 277 women with MS. Data were analysed in a multivariable logistic regression model, with adjustment for possible confounders. RESULTS: Parity was not independently associated with secondary progression, while the factors disease duration (OR per year increase: 1.05, 95% CI 1.03 to 1.09) and use of immunomodulatory treatments (OR 0.23, 95% CI 0.08 to 0.65) were independently associated with secondary progression. CONCLUSION: We found no evidence that parity influences the risk of secondary progression in MS. Further population-based studies on the association of pregnancy and childbirth on the long-term prognosis of MS are needed.

Fatigue, depression and disability accumulation in multiple sclerosis: a cross-sectional study.

OBJECTIVE: To investigate the influence of disability and the speed of disability accumulation on fatigue and depression in a large cohort of patients with multiple sclerosis (MS). METHODS: A total of 412 patients completed the Fatigue Severity Scale (FSS) and Center for Epidemiological Studies Depression Scale (CESD). The patients were registered at our outpatient department and demographic and disease specific data were compared between patients with and without severe fatigue (FSS > or = 5.0) and clinically significant depressive symptoms (CESD > or = 16). We investigated the association of Expanded Disability Status Scale (EDSS) scores, multiple sclerosis severity scores (MSSS) and either CESD scores or FSS-scores with severe fatigue and clinically significant depressive symptoms in a multivariable logistic regression model, with adjustment for possible confounders. RESULTS: Only CESD scores were independently associated with severe fatigue. FSS scores and female gender were independently associated with clinically significant depressive symptoms. Neither EDSS nor MSSS scores were independently associated with fatigue or depression. CONCLUSION: In patients with MS, fatigue and depression are strongly associated with each other but not with the degree of disability or the speed of disability accumulation.