124 research outputs found
The functional relationship between yawning and vigilance
No full textBACKGROUND: Although yawning is a ubiquitous and phylogenetically old phenomenon, its origin and purpose remain unclear. The study aimed at testing the widely held hypothesis that yawning is triggered by drowsiness and brings about a reversal or suspension of the process of falling asleep. METHODS: Subjects complaining of excessive sleepiness were spontaneously yawning while trying to stay awake in a quiet and darkened room. Changes in their electroencephalogram (EEG) and heart rate variability (HRV) associated with yawning were compared to changes associated with isolated voluntary body movements. Special care was taken to remove eye blink- and movement-artefacts from the recorded signals. RESULTS: Yawns were preceded and followed by a significantly greater delta activity in EEG than movements (p< or =0.008). After yawning, alpha rhythms were attenuated, decelerated, and shifted towards central brain regions (p< or =0.01), whereas after movements, they were attenuated and accelerated (p<0.02). A significant transient increase of HRV occurred after the onset of yawning and movements, which was followed by a significant slow decrease peaking 17s after onset (p<0.0001). No difference in HRV changes was found between yawns and movements. CONCLUSIONS: Yawning occurred during periods with increased drowsiness and sleep pressure, but was not followed by a measurable increase of the arousal level of the brain. It was neither triggered nor followed by a specific autonomic activation. Our results therefore confirm that yawns occur due to sleepiness, but do not provide evidence for an arousing effect of yawning
Siegfried In The Interpretations Of The German Film Directors Of The Early 20th – Early 21st Century (Fritz Lang's "The Nibelungs" And Uli Edel`S "Ring Of The Nibelungs")
No full textFilm experts and art historians studied German cinema in detail, however, movies based on “The Song of the Nibelungs” as well as on the German and Scandinavian heroic epic have not yet been investigated by means of modern interdisciplinary approaches. The author pays attention to Siegfried, one of the most important heroes of the German and Scandinavian epic, according to Fritz Lang's (1890 – 1976) and Uli Edel`s (1947) interpretations, divided by almost a century (1924 and 2004). The author analyzes various means of expression: visuality, scenery, actor's performance, credits/dialogues. As far as the Lang's movie is concerned, he concludes that one can interpret the figure of Sigfried on two levels of interpretation. The first is the visual one which includes the actor's performance and the work of support staff (e.g. dress makers, set dressers). It describes him as an extraordinary strong hero. The second one is the semantic level which is formed of credits and music. It creates a myth about Siegfried as the national hero. In Edel's movie, the dialogues between heroes and actor's performance are used as the main means of expression. In Lang’s interpretation, Siegfried is described as the neo-romantic superhero, the person possessing a special force. Uli Edel’s Siegfried obtains dialectic nature – he is the prince, the king, and he is also the commoner; courageous soldier, dragon slayer, and obedient vassal, servant; son of Christian parents, pagan's stepson. The author assumes that Fritz Lang and Uli Edel reacted to inquiries of the time. In the 1920s, Germany suffered a difficult period between the two World Wars, the German people were oppressed by military reparations. Powerful Siegfried, as the national hero and embodiment of the German people, was urged to remind Germans of their great heroic past, to return their self-confidence to them. In our era of globalization and multiculturalism, the idea of association, peaceful co-existence of various ideas and religions was embodied in Siegfried.</jats:p
EEG correlation and power during maintenance of wakefulness test after sleep-deprivation
No full textTo investigate whether there are any objective EEG characteristics that change significantly between specific time periods during maintenance of wakefulness test (MWT) and whether such changes are associated with the ability to appropriately communicate sleepiness
Mechanisms underlying prion protein toxicity and therapeutic strategies
No full textPrion diseases such as Creutzfeldt-Jakob disease (CJD) and Kuru in humans, scrapie in sheep and bovine spongiform encephalopathy (BSE) in cattle are a group of neurodegenerative diseases that invariably lead to death. The current hypothesis states that the cellular prion protein (PrPC) gets converted into a misfolded form
PrPSc, characterized by a high β-sheet content (Aguzzi and Calella, 2009). The misfolded PrPSc oligomerizes and grows into fibrils. Broken fibrils can then serve as a
seed and lead to further conversion and oligomerization, and therefore be used as a surrogate for infectivity (Knowles et al., 2009). The in vivo conformation of prion fibrils is not defined; hence, developing specific inhibitors remains challenging.
Other therapies targeting both prion replication and the intracellular signalling pathways that mediate neurotoxicity have not been successful. Consequently, to date no effective prion therapy exists.
Prion disease represents one if not the best-studied protein aggregation disease. An in vitro model for prion-induced pathology has been established in our laboratory.
When cerebellar organotypic cultured slices (COCS) are infected with prions, they exhibit all the characteristic features as prion replication, astro- and microgliosis,
vacuolation and neurotoxicity (Falsig et al., 2008; Falsig et al., 2012).
Luminescent conjugated polythiophenes (LCP) are polymeric fluorescent molecules that preferentially bind to protein aggregates with regular cross-β-sheet structures,
including those formed by PrPSc, and can be used to stain many different amyloids in tissues (Klingstedt and Nilsson, 2012). Recently, our laboratory found that treatment of prion-infected brain homogenates and prion-infected COCS with LCPs reduced infectivity. Interestingly, the prionostatic effect seems to rely on hyperstabilization, rather than dissociation, of PrP aggregates (Margalith et al., 2012).
More recent findings from our lab have shown that full length, monovalent antibodies or single chain antibodies that target the globular domain (termed globular domain ligands; GDL) of prion protein (PrPC) lead to dramatic neuronal cell loss when applied in cultured organotypic cerebellar slices or stereotactically injected in the cerebellum of mice (Sonati et al., 2013). It was also found that neurotoxicity involves the production of reactive oxygen species and activation of calpains.
This thesis focuses on the evaluation of LCPs as a therapy in a mouse model of prion diseases, the comparison of the pathogenetic mechanisms underlying neurotoxicity elicited by GDL or prions and signaling mechanisms involved in prion induced neuronal cell death
Eyelid Closure Behavior of Patients with Idiopathic and Nonorganic Hypersomnia, Narcolepsy-Cataplexy, and Healthy Controls in the Maintenance of Wakefulness Test
No full textPURPOSE
Differential diagnosis of central disorders of hypersomnolence remains challenging, particularly between idiopathic (IH) and nonorganic hypersomnia (NOH). We hypothesized that eyelid closure behavior in the maintenance of wakefulness test (MWT) could be a valuable biomarker.
PATIENTS AND METHODS
MWT recordings of patients with IH, NOH, narcolepsy-cataplexy (NC), and healthy sleep-deprived controls (H) were retrospectively analyzed (15 individuals per group). For each MWT trial, visual scoring of face videography for partial (50-80%) and full eyelid closure (≥80%) was performed from "lights off" to the first microsleep episode (≥3 s).
RESULTS
In all groups, the frequency and cumulative duration of periods with partial and full eyelid closure gradually increased toward the first microsleep episode. On the group level, significant differences occurred for the latency to the first microsleep episode (IH 21 min (18-33), NOH 23 min (17-35), NC 11 min (7-19), H 10 min (6-25); p = 0.009), the ratio between partial and full eyelid closure duration (IH 2.2 (0.9-3.1), NOH 0.5 (0-1.2), NC 2.8 (1.1-5), H 0.7 (0.4-3.3); p = 0.004), and the difference between full and partial eyelid closure duration in the five minutes prior to the first microsleep episode (∆full - partial eyelid closure duration: IH -16 s (-35 to 28); NOH 46 s (9-82); NC -6 s (-26 to 5); H 10 s (-4 to 18); p = 0.007). IH and NOH significantly differed comparing the ratio between partial and full eyelid closure (p = 0.005) and the difference between ∆full - partial eyelid closure duration in the five minutes prior to the first microsleep episode (p = 0.006).
CONCLUSION
In the MWT, eyelid closure behavior (∆full - partial) in the period prior to the first microsleep episode could be of value for discriminating NOH from other etiologies of excessive daytime sleepiness, particularly IH
Fundamentals of Skill Theory in Fiction (on the Example of the Narrative Genre)
No full textThe article shows the analysis of the basics of skill theory in fiction on the example of the narrative genre with the thoughts of the author. This article also talks about the narrative genre of fiction, as well as an analysis of the opinions and works of thinkers
Eyelid Closure Behavior of Patients with Idiopathic and Nonorganic Hypersomnia, Narcolepsy-Cataplexy, and Healthy Controls in the Maintenance of Wakefulness Test
No full textAnnelies Santschi,1,* David R Schreier,1,* Anneke Hertig-Godeschalk,1 Samuel EJ Knobel,1 Uli S Herrmann,1 Jelena Skorucak,2 Wolfgang J Schmitt,3 Johannes Mathis1,4 1Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; 2University Children’s Hospital Zurich, Zurich, Switzerland; 3University Hospital of Psychiatry, University of Bern, Bern, Switzerland; 4Sleep Medicine, Neurozentrum Bern, Bern, Switzerland*These authors contributed equally to this workCorrespondence: David R Schreier, Department of Neurology, Inselspital, Bern University Hospital, Freiburgstrasse 16, Bern, CH-3010, Switzerland, Tel +41 31 632 21 11, Email [email protected]: Differential diagnosis of central disorders of hypersomnolence remains challenging, particularly between idiopathic (IH) and nonorganic hypersomnia (NOH). We hypothesized that eyelid closure behavior in the maintenance of wakefulness test (MWT) could be a valuable biomarker.Patients and Methods: MWT recordings of patients with IH, NOH, narcolepsy-cataplexy (NC), and healthy sleep-deprived controls (H) were retrospectively analyzed (15 individuals per group). For each MWT trial, visual scoring of face videography for partial (50– 80%) and full eyelid closure (≥ 80%) was performed from “lights off” to the first microsleep episode (≥ 3 s).Results: In all groups, the frequency and cumulative duration of periods with partial and full eyelid closure gradually increased toward the first microsleep episode. On the group level, significant differences occurred for the latency to the first microsleep episode (IH 21 min (18– 33), NOH 23 min (17– 35), NC 11 min (7– 19), H 10 min (6– 25); p = 0.009), the ratio between partial and full eyelid closure duration (IH 2.2 (0.9– 3.1), NOH 0.5 (0– 1.2), NC 2.8 (1.1– 5), H 0.7 (0.4– 3.3); p = 0.004), and the difference between full and partial eyelid closure duration in the five minutes prior to the first microsleep episode (∆full – partial eyelid closure duration: IH − 16 s (− 35 to 28); NOH 46 s (9– 82); NC − 6 s (− 26 to 5); H 10 s (− 4 to 18); p = 0.007). IH and NOH significantly differed comparing the ratio between partial and full eyelid closure (p = 0.005) and the difference between ∆full – partial eyelid closure duration in the five minutes prior to the first microsleep episode (p = 0.006).Conclusion: In the MWT, eyelid closure behavior (∆full – partial) in the period prior to the first microsleep episode could be of value for discriminating NOH from other etiologies of excessive daytime sleepiness, particularly IH.Keywords: hypersomnia, hypersomnia associated with psychiatric disorders, excessive daytime sleepiness, vigilance test, central disorders of hypersomnolence, microslee
Hematopoietic stem cell transplantation for purine nucleoside phosphorylase deficiency: an EBMT-IEWP retrospective study
No full textError estimation and adjoint-based adaptation in aerodynamics
No full textIn this article we give an overview of recent developments
in error estimation and in residual-based and goal-oriented
(adjoint-based) adaptation for Discontinuous Galerkin discretizations
of sub- and supersonic viscous compressible flows. We also give an
outlook on the planned continuation of this research in the EU project
ADIGMA
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