Media sharing websites and the US financial markets

Recently, one of the main issues of concern within the world wide web is the understanding of web 2.0 mass collaboration systems. These systems have emerged in recent years and gained enormous popularity. It must, however, be pointed out, that the potential and practical application of web 2.0 are still not well understood and deserve academic attention. In this paper we investigate the online media sharing collaborative community and its applications for uses in stock market analysis and prediction. Specifically, we look at Youtube.com, one of the most popular social media sharing websites. The association with stock market behaviour and usage patterns are investigated. This work became of more interest and significance with the recent credit crunch crisis. The data under investigation is novel, and to our knowledge, this paper reports the first investigation of its kind to the use of collaborative media sharing website for stock market analysis. We find significant association between video meta-data and textual data using a content driven sentiment text mining approach. The results are very encouraging and importantly highlight efficient information transfer to online media sharing communities as there seems to be predictive value in youtube data

Impact of statin use and lipid profile on symptomatic intracerebral haemorrhage, outcome and mortality after intravenous thrombolysis in acute stroke

Background: It is unclear if a certain lipid profile and/or statin use contribute to symptomatic intracerebral haemorrhage (sICH), poor outcome or mortality after intravenous thrombolysis for ischaemic stroke. The aim of the current study was to assess the impact of statin use and lipid profile on sICH, outcome and mortality following thrombolysis in acute stroke. Methods: From 2001 to 2010, all patients admitted to our hospital and undergoing intravenous thrombolysis for acute ischaemic stroke were included into an open, prospective database. Initial stroke severity was assessed using the National Institute of Health Stroke Scale. Demographics, vascular risk factors, admission blood pressure, glucose levels, previous medication including statin use, lipid profiles including low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride levels were recorded. Outcome measures included sICH according to the European Cooperative Acute Stroke Study II criteria, modified Rankin scale and mortality at 3 months. Results: 1,066 patients were included in the analysis; 5.3% (57 patients) had sICH. Mortality at 3 months was 17.6% (188 patients). A favourable outcome (modified Rankin scale 0-1) at 3 months was attained by 35.6% (379 patients). Prior statin use was not associated with increased odds for sICH (OR 1.05, 95% CI 0.55–2.04, p = 0.864), mortality (OR 1.32, 95% CI 0.90–1.93, p = 0.152) or favourable outcome (OR 0.89, 95% CI 0.65–1.24, p = 0.507). Similar results were found for the different lipid variables: high LDL (OR 0.96, 95% CI 0.36–2.60, p = 0.942), high triglyceride (OR 1.74, 95% CI 0.84–3.56, p = 0.132) and low HDL (OR 1.78, 95% CI 0.68–4.65, p = 0.279) were not associated with increased odds for sICH. Likewise, neither mortality nor functional outcome at 3 months was significantly associated with any of the lipid variables in the univariable analysis following Bonferroni adjustment for multiple comparisons. The same results were found in the multivariable analysis adjusting for imbalances in baseline characteristics. Conclusions: In contrast to previous studies, we found that in stroke patients receiving thrombolysis therapy, neither the lipid profile nor prior statin use were associated with increased odds for sICH, functional outcome or mortality at 3 months

Optimal cerebral perfusion pressure in patients with intracerebral hemorrhage: an observational case series

Introduction: Current guidelines for spontaneous intracerebral hemorrhage (ICH) recommend maintaining cerebral perfusion pressure (CPP) between 50 and 70 mmHg, depending on the state of autoregulation. We continuously assessed dynamic cerebral autoregulation and the possibility of determination of an optimal CPP (CPPopt) in ICH patients. Associations between autoregulation, CPPopt and functional outcome were explored. Methods: Intracranial pressure (ICP), mean arterial pressure (MAP) and CPP were continuously recorded in 55 patients, with 38 patients included in the analysis. The pressure reactivity index (PRx) was calculated as moving correlation between MAP and ICP. CPPopt was defined as the CPP associated with the lowest PRx values. CPPopt was calculated using hourly updated of 4 hour windows. The modified Rankin Scale (mRS) was assessed at 3 months and associations between PRx, CPPopt and outcomes were explored using Pearson correlation and Fisher’s exact test. Multivariate stepwise logistic regression models were calculated including standard outcome predictors along with percentage of time with PRx >0.2 and percentage of time within the CPPopt range. Results: An overall PRx indicating impairment of pressure reactivity was found in 47% of patients (n = 18). The mean PRx and the time spent with a PRx > 0.2 significantly correlated with mRS at 3 months (r = 0.50, P = 0.002; r = 0.46, P = 0.004). CPPopt was calculable during 57% of the monitoring time. The median CPP was 78 mmHg, the median CPPopt 83 mmHg. Mortality was lowest in the group of patients with a CPP close to their CPPopt. However, for none of the CPPopt variables a significant association to outcome was found. The percentage of time with impaired autoregulation and hemorrhage volume were independent predictors for acceptable outcome (mRS 1 to 4) at three months. Conclusions: Failure of pressure reactivity seems common following severe ICH and is associated with unfavorable outcome. Real-time assessment of CPPopt is feasible in ICH and might provide a tool for an autoregulation-oriented CPP management. A larger trial is needed to explore if a CPPopt management results in better functional outcomes

Blood pressure variability after intravenous thrombolysis in acute stroke does not predict intracerebral hemorrhage but poor outcome

Background: The relevance of blood pressure variability (BPV) in the development of intracerebral hemorrhage (ICH) after intravenous thrombolysis (IVT) in acute stroke still remains uncertain. Methods: 427 consecutive patients treated with IVT in the years 2007-2009 were studied. Blood pressure (BP) values were analyzed from admission to follow-up imaging scan and described as mean, maximum, minimum, standard deviation (SD), difference between maximum and minimum, successive variation (SV) and maximum SV. ICH was categorized based on radiologic criteria and symptomatic ICH (sICH) was defined as ICH plus worsening of the National Institute of Health Stroke Scale by 6 4 points or leading to death. Three-month outcome was described by means of the modified Rankin Scale. Results: We observed any ICH in 51 (11.9%) and sICH in 10 (2.3%) patients. Systolic and diastolic BP profiles, including mean, maximum, minimum, SD, difference between maximum and minimum, SV and maximum SV, did not differ between ICH-negative, ICH-positive and sICH patients

Baroreflex Impairment After Subarachnoid Hemorrhage Is Associated With Unfavorable Outcome.

BACKGROUND AND PURPOSE: Aneurysmal subarachnoid hemorrhage (SAH) is characterized by important changes in the autonomic nervous system with potentially adverse consequences. The baroreflex has a key role in regulating the autonomic nervous system. Its role in SAH outcome is not known. The purpose of this study was to evaluate the association between the baroreflex and the functional 3-month outcome in SAH. METHODS: The study used a prospective database of 101 patients hospitalized for SAH. We excluded patients receiving β-blockers or noradrenaline. Baroreflex sensitivity (BRS) was measured using the cross-correlation method. A good outcome was defined by a Glasgow Outcome Scale score at 4 or 5 at 3 months. RESULTS: Forty-eight patients were included. Median age was 58 years old (36-76 years); women/men: 34/14. The World Federation of Neurosurgery clinical severity score on admission was 1 or 2 for 73% of patients. In the univariate analysis, BRS (P=0.007), sedation (P=0.001), World Federation of Neurosurgery score (P=0.001), Glasgow score (P=0.002), Fisher score (P=0.022), and heart rate (P=0.037) were associated with outcome. The area under the receiver operating characteristic curve for the model with BRS as a single predictor was estimated at 0.835. For each unit increase in BRS, the odds for a good outcome were predicted to increase by 31%. Area under the receiver operating characteristic curve for heart rate alone was 0.670. In the multivariate analysis, BRS (odds ratio, 1.312; 95% confidence interval, 1.048-1.818; P=0.018) and World Federation of Neurosurgery (odds ratio, 0.382; 95% confidence interval, 0.171-0.706; P=0.001) were significantly associated with outcome. Area under the receiver operating characteristic curve was estimated at 0.900. CONCLUSIONS: In SAH, early BRS was associated with 3-month outcome. This conclusion requires confirmation on a larger number of patients in a multicentre study

Relationship Between Baroreflex and Cerebral Autoregulation in Patients With Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage.

Introduction: Common consequences following aneurysmal subarachnoid hemorrhage (aSAH) are cerebral vasospasm (CV), impaired cerebral autoregulation (CA), and disturbance in the autonomic nervous system, as indicated by lower baroreflex sensitivity (BRS). The compensatory interaction between BRS and CA has been shown in healthy volunteers and stable pathological conditions such as carotid atherosclerosis. The aim of this study was to investigate whether the inverse correlation between BRS and CA would be lost in patients after aSAH during vasospasm. A secondary objective was to analyze the time-trend of BRS after aSAH. Materials and Methods: Retrospective analysis of prospectively collected data was performed at the Neuro-Critical Care Unit of Addenbrooke's Hospital (Cambridge, UK) between June 2010 and January 2012. The cerebral blood flow velocity (CBFV) was measured in the middle cerebral artery using transcranial Doppler ultrasonography (TCD). The arterial blood pressure (ABP) was monitored invasively through an arterial line. CA was quantified by the correlation coefficient (Mxa) between slow oscillations in ABP and CBFV. BRS was calculated using the sequential cross-correlation method using the ABP signal. Results: A total of 73 patients with aSAH were included. The age [median (lower-upper quartile)] was 58 (50-67). WFNS scale was 2 (1-4) and the modified Fisher scale was 3 (1-3). In the total group, 31 patients (42%) had a CV and 42 (58%) had no CV. ABP and CBFV were higher in patients with CV during vasospasm compared to patients without CV (p = 0.001 and p < 0.001). There was no significant correlation between Mxa and BRS in patients with CV, neither during nor before vasospasm. In patients without CV, a significant, although moderate correlation was found between BRS and Mxa (rS = 0.31; p = 0.040), with higher BRS being associated with worse CA. Multiple linear regression analysis showed a significant worsening of BRS after aSAH in patients with CV (R p = -0.42; p < 0.001). Conclusions: Inverse compensatory correlation between BRS and CA was lost in patients who developed CV after aSAH, both before and during vasospasm. The impact of these findings on the prognosis of aSAH should be investigated in larger studies

Structural and catalytic effects of surface loop-helix transplantation within haloalkane dehalogenase family

Engineering enzyme catalytic properties is important for basic research as well as for biotechnological applications. We have previously shown that the reshaping of enzyme access tunnels via the deletion of a short surface loop element may yield a haloalkane dehalogenase variant with markedly modified substrate specificity and enantioselectivity. Here, we conversely probed the effects of surface loop-helix transplantation from one enzyme to another within the enzyme family of haloalkane dehalogenases. Precisely, we transplanted a nine-residue long extension of L9 loop and alpha 4 helix from DbjA into the corresponding site of DbeA. Biophysical characterization showed that this fragment transplantation did not affect the overall protein fold or oligomeric state, but lowered protein stability (Delta T-m = -5 to 6 degrees C). Interestingly, the crystal structure of DbeA mutant revealed the unique structural features of enzyme access tunnels, which are known determinants of catalytic properties for this enzyme family. Biochemical data confirmed that insertion increased activity of DbeA with various halogenated substrates and altered its enantioselectivity with several linear beta-bromoalkanes. Our findings support a protein engineering strategy employing surface loop-helix transplantation for construction of novel protein catalysts with modified catalytic properties