Hypomyelinating leukodystrophies represent a genetically heterogeneous but clinically overlapping group of heritable disorders. Current management approaches in the care of the patient with a ...hypomyelinating leukodystrophy include use of serial magnetic resonance imaging (MRI) to establish and monitor hypomyelination, molecular diagnostics to determine a specific etiology, and equally importantly, careful attention to neurologic complications over time. Emerging research in oligodendrocyte biology and neuroradiology with bedside applications may result in the possibility of clinical trials in the near term, yet there are significant gaps in knowledge in disease classification, characterization, and outcome measures in this group of disorders. Here we review the biological background of myelination, the clinical and genetic variability in hypomyelinating leukodystrophies, and the insights that can be obtained from current MRI techniques. In addition, we discuss ongoing research approaches to define potential outcome markers for future clinical trials. Ann Neurol 2014;76:5–19
Flooding is expected to increase in frequency and severity in the future. The ecological consequences of flooding are the combined result of species-specific plant traits and ecological context. ...However, the majority of past flooding research has focused on individual model species under highly controlled conditions.
An early summer flooding event in a grassland biodiversity experiment in Jena, Germany, provided the opportunity to assess flooding responses of 60 grassland species in monocultures and 16-species mixtures. We examined plant biomass, species-specific traits (plant height, specific leaf area (SLA), root aerenchyma, starch content) and soil porosity.
We found that, on average, plant species were less negatively affected by the flood when grown in higher-diversity plots in July 2013. By September 2013, grasses were unaffected by the flood regardless of plant diversity, and legumes were severely negatively affected regardless of plant diversity. Plants with greater SLA and more root aerenchyma performed better in September. Soil porosity was higher in higher-diversity plots and had a positive effect on plant performance.
As floods become more frequent and severe in the future, growing flood-sensitive plants in higher-diversity communities and in soil with greater soil aeration may attenuate the most negative effects of flooding.
Titin-truncating variants (TTNtv) commonly cause dilated cardiomyopathy (DCM). TTNtv are also encountered in ∼1% of the general population, where they may be silent, perhaps reflecting allelic ...factors. To better understand TTNtv, we integrated TTN allelic series, cardiac imaging and genomic data in humans and studied rat models with disparate TTNtv. In patients with DCM, TTNtv throughout titin were significantly associated with DCM. Ribosomal profiling in rat showed the translational footprint of premature stop codons in Ttn, TTNtv-position-independent nonsense-mediated degradation of the mutant allele and a signature of perturbed cardiac metabolism. Heart physiology in rats with TTNtv was unremarkable at baseline but became impaired during cardiac stress. In healthy humans, machine-learning-based analysis of high-resolution cardiac imaging showed TTNtv to be associated with eccentric cardiac remodeling. These data show that TTNtv have molecular and physiological effects on the heart across species, with a continuum of expressivity in health and disease.
OBJECTIVETo compare outcomes after endovascular treatment (EVT) for acute ischemic stroke with 3 different types of anesthetic management in clinical practice, as anesthetic management may influence ...functional outcome.
METHODSData of patients with an anterior circulation occlusion, included in the Dutch nationwide, prospective Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry between March 2014 and June 2016, were analyzed. Patients were divided into 3 groups defined by anesthetic technique performed during EVTlocal anesthesia only (LA), general anesthesia (GA), or conscious sedation (CS). Primary outcome was the modified Rankin Scale score at 90 days. To compare functional outcome between groups, we estimated a common odds ratio (OR) with ordinal logistic regression, adjusted for age, sex, prestroke modified Rankin Scale score, baseline NIH Stroke Scale score, collaterals, and time from onset to arrival at intervention center.
RESULTSA total of 1,376 patients were included. Performed anesthetic technique was LA in 821 (60%), GA in 381 (28%), and CS in 174 (13%) patients. Compared to LA, both GA and CS were associated with worse functional outcome on the modified Rankin Scale score at 90 days (GA cORadj 0.75; 95% confidence interval CI 0.58–0.97; CS cORadj 0.45; 95% CI 0.33–0.62). CS was associated with worse functional outcome than GA (cORadj 0.60; 95% CI 0.42–0.87).
CONCLUSIONSLA is associated with better functional outcome than systemic sedation in patients undergoing EVT for acute ischemic stroke. Whereas LA had a clear advantage over CS, this was less prominent compared to GA.
CLASSIFICATION OF EVIDENCEThis study provides Class III evidence that for patients with acute ischemic stroke undergoing EVT, LA improves functional outcome compared to GA or CS.
Gamma-aminobutyric acid (GABA) and glutamate (Glu) are the major neurotransmitters in the brain. They are crucial for the functioning of healthy brain and their alteration is a major mechanism in the ...pathophysiology of many neuro-psychiatric disorders.
Magnetic resonance spectroscopy (MRS) is the only way to measure GABA and Glu non-invasively in vivo. GABA detection is particularly challenging and requires special MRS techniques. The most popular is MEscher–GArwood (MEGA) difference editing with single-voxel Point RESolved Spectroscopy (PRESS) localization. This technique has three major limitations: a) MEGA editing is a subtraction technique, hence is very sensitive to scanner instabilities and motion artifacts. b) PRESS is prone to localization errors at high fields (≥3T) that compromise accurate quantification. c) Single-voxel spectroscopy can (similar to a biopsy) only probe steady GABA and Glu levels in a single location at a time.
To mitigate these problems, we implemented a 3D MEGA-editing MRS imaging sequence with the following three features: a) Real-time motion correction, dynamic shim updates, and selective reacquisition to eliminate subtraction artifacts due to scanner instabilities and subject motion. b) Localization by Adiabatic SElective Refocusing (LASER) to improve the localization accuracy and signal-to-noise ratio. c) K-space encoding via a weighted stack of spirals provides 3D metabolic mapping with flexible scan times.
Simulations, phantom and in vivo experiments prove that our MEGA-LASER sequence enables 3D mapping of GABA+ and Glx (Glutamate+Gluatmine), by providing 1.66 times larger signal for the 3.02ppm multiplet of GABA+ compared to MEGA-PRESS, leading to clinically feasible scan times for 3D brain imaging.
Hence, our sequence allows accurate and robust 3D-mapping of brain GABA+ and Glx levels to be performed at clinical 3T MR scanners for use in neuroscience and clinical applications.
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•MEGA-LASER provided >1.66 times larger GABA signal integral than MEGAPRESS.•MEGA-LASER was insensitive to B1+ and chemical shift related artifacts.•Real-time position and B0 updates with selective reacquisition reduced subtraction artifacts in MEGA-editing.•Spiral encoding allowed 3D mapping of GABA+ in the same time as normally required for single-voxel MRS.
Scientific progress depends on the ability of independent researchers to scrutinize the results of a research study, to reproduce the study's main results using its materials, and to build on them in ...future studies (https://www.nature.com/nature-research/editorial-policies/reporting-standards). Nuances in the computer code may have marked effects on the training and evaluation of results4, potentially leading to unintended consequences5. ...transparency in the form of the actual computer code used to train a model and arrive at its final set of parameters is essential for research reproducibility. The many software dependencies of large-scale machine learning applications require appropriate control of the software environment, which can be achieved through package managers including Conda, as well as container and virtualization systems, including Code Ocean, Gigantum, Colaboratory and Docker. Sharing the fitted model (architecture along with learned parameters) should be simple aside from privacy concerns that the model may reveal sensitive information about the set of patients used to train it.
Iron (Fe) is an essential nutrient in plants and animals, and Fe deficiency results in decreased vitality and performance. Due to limited bio-availability of Fe, plants have evolved sophisticated ...adaptive alterations in development, biochemistry and metabolism that are mainly regulated at the transcriptional level. We have investigated the early transcriptional response to Fe deficiency in roots of the model plant Arabidopsis, using a hydroponic system that permitted removal of Fe from the nutrient solution within seconds and transferring large numbers of plants with little or no mechanical damage to the root systems. We feel that this experimental approach offers significant advantages over previous and recent DNA microarray investigations of the Fe-deficiency response by increasing the resolution of the temporal response and by decreasing non-Fe deficiency-induced transcriptional changes, which are common in microarray analyses.
The expression of sixty genes were changed after 6 h of Fe deficiency and 65% of these were found to overlap with a group of seventy-nine genes that were altered after 24 h. A disproportionally high number of transcripts encoding ion transport proteins were found, which function to increase the Fe concentration and decrease the zinc (Zn) concentration in the cytosol. Analysis of global changes in gene expression revealed that changes in Fe availability were associated with the differential expression of genes that encode transporters with presumed function in uptake and distribution of transition metals other than Fe. It appeared that under conditions of Fe deficiency, the capacity for Zn uptake increased, most probably the result of low specificity of the Fe transporter IRT1 that was induced upon Fe deficiency. The transcriptional regulation of several Zn transports under Fe deficiency led presumably to the homeostatic regulation of the cytosolic concentration of Zn and of other transition metal ions such as Mn to avoid toxicity.
The genomic information obtained from this study gives insights into the rapid transcriptional responses to Fe shortage in plants, and is important for understanding how changes in nutrient availability are translated into responses that help to avoid imbalances in ion distribution. We further identified rapidly induced or repressed genes with potential roles in perception and signaling during Fe deficiency which may aid in the elucidation of these processes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
OBJECTIVETo determine public health and cost consequences of time delays to endovascular thrombectomy (EVT) for patients, health care systems, and society, we estimated quality-adjusted life-years ...(QALYs) of EVT-treated patients and associated costs based on times to treatment.
METHODSThe Markov model analysis was performed from US health care and societal perspectives over a lifetime horizon. Contemporary data from 7 trials within the Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials (HERMES) collaboration served as data source. Aside from cumulative lifetime costs, we calculated the net monetary benefit (NMB) to determine the economic value of care. We used a contemporary willingness-to-pay threshold of $100,000 per QALY for NMB calculations.
RESULTSEvery 10 minutes of earlier treatment resulted in an average gain of 39 days (95% prediction interval 23–53 days) of disability-free life. Overall, the cumulative lifetime costs for patients with earlier or later treatment were similar. Patients with later treatment had higher morbidity-related costs but over a shorter time span due to their shorter life expectancy, resulting in similar lifetime costs as in patients with early treatment. Regarding the economic value of care, every 10 minutes of earlier treatment increased the NMB by $10,593 (95% prediction interval $5,549–$14,847) and by $10,915 (95% prediction interval $5,928–$15,356) taking health care and societal perspectives, respectively.
CONCLUSIONSAny time delay to EVT reduces QALYs and decreases the economic value of care provided by this intervention. Health care policies to implement efficient prehospital triage and to accelerate in-hospital workflow are urgently needed.
Phosphate (Pi) deficiency triggers the differential expression of a large set of genes, which communally adapt the plant to low Pi bioavailability. To infer functional modules in early ...transcriptional responses to Pi deficiency, we conducted time-course microarray experiments and subsequent coexpression-based clustering of Pi-responsive genes by pairwise comparison of genes against a customized database. Three major clusters, enriched in genes putatively functioning in transcriptional regulation, root hair formation, and developmental adaptations, were predicted from this analysis. Validation of gene expression by quantitative reverse transcription-PCR revealed that transcripts from randomly selected genes were robustly induced within the first hour after transfer to Pi-deplete medium. Pectin-related processes were among the earliest and most robust responses to Pi deficiency, indicating that cell wall alterations are critical in the early transcriptional response to Pi deficiency. Phenotypical analysis of homozygous mutants defective in the expression of genes from the root hair cluster revealed eight novel genes involved in Pi deficiency-induced root hair elongation. The plants responded rapidly to Pi deficiency by the induction of a subset of transcription factors, followed by a repression of genes involved in cell wall alterations. The combined results provide a novel, integrated view at a systems level of the root responses that acclimate Arabidopsis (Arabidopsis thaliana) to suboptimal Pi levels.
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