102 research outputs found

    Complications and outcome in patients with aneurysmal subarachnoid haemorrhage: a prospective hospital based cohort study in the Netherlands

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    OBJECTIVE—The aim of this study was to investigate prospectively in an unselected series of patients with an aneurysmal subarachnoid haemorrhage what at present the complications are, what the outcome is, how many of these patients have "modern treatment"—that is, early obliteration of the aneurysm and treatment with calcium antagonists—what factors cause a delay in surgical or endovascular treatment, and what the estimated effect on outcome will be of improved treatment.
METHODS—A prospective, observational cohort study of all patients with aneurysmal subarachnoid haemorrhage in the hospitals of a specified region in The Netherlands. The condition on admission, diagnostic procedures, and treatments were recorded. If a patient had a clinical deterioration, the change in Glasgow coma score (GCS), the presence of focal neurological signs, the results of additional investigations, and the final diagnosed cause of the deterioration were recorded.
 Clinical outcome was assessed with the Glasgow outcome scale (GOS) at 3 month follow up. In patients with poor outcome at follow up, the cause was diagnosed.
RESULTS—Of the 110 patients, 47 (43%) had a poor outcome. Cerebral ischaemia, 31 patients (28%), was the most often occurring complication. Major causes of poor outcome were the effects of the initial haemorrhage and rebleeding in 34% and 30% of the patients with poor outcome respectively. Of all patients 102 (93%) were treated with calcium antagonists and 45 (41%) patients had early treatment to obliterate the aneurysm. The major causes of delay of treatment were a poor condition on admission or deterioration shortly after admission, in 31% and 23% respectively.
CONCLUSIONS—In two thirds of the patients with poor outcome the causes of poor outcome are the effects of the initial bleeding and rebleeding. Improved treatment of delayed or postoperative ischaemia will have only minor effects on the outcome of patients with subarachnoid haemorrhage.


    NK cell phenotypic and functional shifts coincide with specific clinical phases in the natural history of chronic HBV infection

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    Background Chronic HBV infection can be divided into 4 distinct clinical phases: immune tolerant, immune active, inactive carrier, and HBeAg-negative hepatitis. Using a systems biology approach, we recently identified innate immune response components, specifically NK cells as a distinctive factor of specific HBV clinical phases. To expand on this study and identify the underlying immunological mechanisms, we performed a comprehensive profiling of NK cells in chronic HBV infection. Methods Peripheral blood from untreated chronic HBV patients was used to analyze phenotypic markers, as well as cytokine production and cytoxicity of NK cells. Results The overall composition, phenotype, and cytolytic activity of the NK cells remained constant across all clinical phases, with the exception of a few specific markers (KIRs, NKp46). CD56bright NK cells of chronic HBV patients differed in their ability to produce IFN-γ between the clinical phases pre- and post-HBeAg seroconversion. Conclusion This depicts a shift in NK cell characteristics between the immune active, under heavy viral or immune pressure, and inactive carrier phases, that coincides

    PyCOOL - a Cosmological Object-Oriented Lattice code written in Python

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    There are a number of different phenomena in the early universe that have to be studied numerically with lattice simulations. This paper presents a graphics processing unit (GPU) accelerated Python program called PyCOOL that solves the evolution of scalar fields in a lattice with very precise symplectic integrators. The program has been written with the intention to hit a sweet spot of speed, accuracy and user friendliness. This has been achieved by using the Python language with the PyCUDA interface to make a program that is easy to adapt to different scalar field models. In this paper we derive the symplectic dynamics that govern the evolution of the system and then present the implementation of the program in Python and PyCUDA. The functionality of the program is tested in a chaotic inflation preheating model, a single field oscillon case and in a supersymmetric curvaton model which leads to Q-ball production. We have also compared the performance of a consumer graphics card to a professional Tesla compute card in these simulations. We find that the program is not only accurate but also very fast. To further increase the usefulness of the program we have equipped it with numerous post-processing functions that provide useful information about the cosmological model. These include various spectra and statistics of the fields. The program can be additionally used to calculate the generated curvature perturbation. The program is publicly available under GNU General Public License at https://github.com/jtksai/PyCOOL . Some additional information can be found from http://www.physics.utu.fi/tiedostot/theory/particlecosmology/pycool/ .Comment: 23 pages, 12 figures; some typos correcte

    Rare functional missense variants in CACNA1H: what can we learn from Writer's cramp?

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    Writer's cramp (WC) is a task-specific focal dystonia that occurs selectively in the hand and arm during writing. Previous studies have shown a role for genetics in the pathology of task-specific focal dystonia. However, to date, no causal gene has been reported for task-specific focal dystonia, including WC. In this study, we investigated the genetic background of a large Dutch family with autosomal dominantinherited WC that was negative for mutations in known dystonia genes. Whole exome sequencing identified 4 rare variants of unknown significance that segregated in the family. One candidate gene was selected for follow-up, Calcium Voltage-Gated Channel Subunit Alpha1 H, CACNA1H, due to its links with the known dystonia gene Potassium Channel Tetramerization Domain Containing 17, KCTD17, and with paroxysmal movement disorders. Targeted resequencing of CACNA1H in 82 WC cases identified another rare, putative damaging variant in a familial WC case that did not segregate. Using structural modelling and functional studies in vitro, we show that both the segregating p.Arg481Cys variant and the non-segregating p.Glu1881Lys variant very likely cause structural changes to the Cav3.2 protein and lead to similar gains of function, as seen in an accelerated recovery from inactivation. Both mutant channels are thus available for re-activation earlier, which may lead to an increase in intracellular calcium and increased neuronal excitability. Overall, we conclude that rare functional variants in CACNA1H need to be interpreted very carefully, and additional studies are needed to prove that the p.Arg481Cys variant is the cause of WC in the large Dutch family.Genetics of disease, diagnosis and treatmen

    Comparative interactomics analysis of different ALS-associated proteins identifies converging molecular pathways

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    Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment available. An increasing number of genetic causes of ALS are being identified, but how these genetic defects lead to motor neuron degeneration and to which extent they affect common cellular pathways remains incompletely understood. To address these questions, we performed an interactomic analysis to identify binding partners of wild-type (WT) and ALS-associated mutant versions of ATXN2, C9orf72, FUS, OPTN, TDP-43 and UBQLN2 in neuronal cells. This analysis identified several known but also many novel binding partners of these proteins. Interactomes of WT and mutant ALS proteins were very similar except for OPTN and UBQLN2, in which mutations caused loss or gain of protein interactions. Several of the identified interactomes showed a high degree of overlap: shared binding partners of ATXN2, FUS and TDP-43 had roles in RNA metabolism; OPTN- and UBQLN2-interacting proteins were related to protein degradation and protein transport, and C9orf72 interactors function in mitochondria. To conf

    Local linear regression with adaptive orthogonal fitting for the wind power application

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    Short-term forecasting of wind generation requires a model of the function for the conversion of me-teorological variables (mainly wind speed) to power production. Such a power curve is nonlinear and bounded, in addition to being nonstationary. Local linear regression is an appealing nonparametric ap-proach for power curve estimation, for which the model coefficients can be tracked with recursive Least Squares (LS) methods. This may lead to an inaccurate estimate of the true power curve, owing to the assumption that a noise component is present on the response variable axis only. Therefore, this assump-tion is relaxed here, by describing a local linear regression with orthogonal fit. Local linear coefficients are defined as those which minimize a weighted Total Least Squares (TLS) criterion. An adaptive es-timation method is introduced in order to accommodate nonstationarity. This has the additional benefit of lowering the computational costs of updating local coefficients every time new observations become available. The estimation method is based on tracking the left-most eigenvector of the augmented covari-ance matrix. A robustification of the estimation method is also proposed. Simulations on semi-artificial datasets (for which the true power curve is available) underline the properties of the proposed regression and related estimation methods. An important result is the significantly higher ability of local polynomia
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