2,159 research outputs found
The spatiotemporal pattern of the human electroencephalogram at sleep onset after a period of prolonged wakefulness
During the sleep onset (SO) process, the human electroencephalogram (EEG) is characterized by an orchestrated pattern of spatiotemporal changes. Sleep deprivation (SD) strongly affects both wake and sleep EEG, but a description of the topographical EEG power spectra and oscillatory activity during the wake-sleep transition after a period of prolonged wakefulness is still missing. The increased homeostatic sleep pressure should induce an earlier onset of sleep-related EEG oscillations. The aim of the present study was to assess the spatiotemporal EEG pattern at SO following SD. A dataset of a previous study was analyzed. We assessed the spatiotemporal EEG changes (19 cortical derivations) during the SO (5 min before vs. 5 min after the first epoch of Stage 2) of a recovery night after 40 h of SD in 39 healthy subjects, analyzing the EEG power spectra (fast Fourier transform) and the oscillatory activity [better oscillation (BOSC) detection method]. The spatiotemporal pattern of the EEG power spectra mostly confirmed the changes previously observed during the wake-sleep transition at baseline. The comparison between baseline and recovery showed a wide increase of the post- vs. pre-SO ratio during the recovery night in the frequency bins 10 Hz. We found a predominant alpha oscillatory rhythm in the pre-SO period, while after SO the theta oscillatory activity was prevalent. The oscillatory peaks showed a generalized increase in all frequency bands from delta to sigma with different predominance, while beta activity increased only in the fronto-central midline derivations. Overall, the analysis of the EEG power replicated the topographical pattern observed during a baseline night of sleep but with a stronger intensity of the SO-induced changes in the frequencies 10 Hz, and the detection of the rhythmic activity showed the rise of several oscillations at SO after SD that was not observed during the wake-sleep transition at baseline (e.g., alpha and frontal theta in correspondence of their frequency peaks). Beyond confirming the local nature of the EEG pattern at SO, our results show that SD has an impact on the spatiotemporal modulation of cortical activity during the falling-asleep process, inducing the earlier emergence of sleep-related EEG oscillations
A case of acute aortic dissection type b associated with cushing's syndrome
We report a case of a 63-year-old man, with a previous history of hypertension and glucose intolerance associated troncular obesity that was emergently admitted to our Institution for evaluation of a severe, constant posterior chest pain which radiated anteriorly and dyspnoea with a suspected diagnosis of acute aortic dissection. A CT scan of thorax and abdomen demonstrated a dissection starting just below left succlavian artery and extending downward to the left renal artery, involving the celiac tripod and superior mesenteric artery. The dissection was classified as Stanford B, De Bakey III. Moreover, CT scan of abdomen revealed incidentally a left adrenal tumor of 25 mm of diameter. An emergent prosthetic graft was placed just below the origin of the left succlavian artery up-to the diaphragmatic hiatus. Furthermore, a diagnostic evaluation of the mass revealed an increase of cortisol production, and a diagnosis of Cushing's syndrome was done and the patient underwent an adrenalectomy via laparotomic approach. We report an association of acute aortic dissection of acute aortic dissection type B associated to Cushing's syndrome. Cushing's syndrome; Adrenocortical adenoma; Aortic dissection type B
Localization versus inhomogeneous superfluidity: Submonolayer He-4 on fluorographene, hexagonal boron nitride, and graphene
We study a sub monolayer He-4 adsorbed on fluorographene (GF) and on
hexagonal boron nitride (hBN) at low coverage. The adsorption potentials have
been computed ab-initio with a suitable density functional theory including
dispersion forces. The properties of the adsorbed He-4 atoms have been computed
at finite temperature with path integral Monte Carlo and at T=0 K with
variational path integral. From both methods we find that the lowest energy
state of He-4 on GF is a superfluid. Due to the very large corrugation of the
adsorption potential this superfluid has a very strong spatial anisotropy, the
ratio between the largest and smallest areal density being about 6, the
superfluid fraction at the lowest T is about 55%, and the temperature of the
transition to the normal state is in the range 0.5-1 K. Thus, GF offers a
platform for studying the properties of a strongly interacting highly
anisotropic bosonic superfluid. At a larger coverage He-4 has a transition to
an ordered commensurate state with occupation of 1/6 of the adsorption sites.
This phase is stable up to a transition temperature located between 0.5 and
1~K. The system has a triangular order similar to that of He-4 on graphite. The
lowest energy state of He-4 on hBN is an ordered commensurate state with
occupation of 1/3 of the adsorption sites and triangular symmetry. A disordered
state is present at lower coverage as a metastable state. In the presence of an
electric field the corrugation of the adsorption potential is slightly
increased but up to a magnitude of 1 V/Ang. the effect is small and does not
change the stability of the phases of He-4 on GF and hBN. We have verified that
also in the case of graphene such electric field does not modify the stability
of the commensurate sqrt{3}*sqrt{3}R30 phase.Comment: 12 pages, 14 figure
The paradox of Zeno in bariatric surgery weight loss: Superobese patients run faster than morbidly obese patients, but can't overtake them
Results on Proton-Irradiated 3D Pixel Sensors Interconnected to RD53A Readout ASIC
Test beam results obtained with 3D pixel sensors bump-bonded to the RD53A
prototype readout ASIC are reported. Sensors from FBK (Italy) and IMB-CNM
(Spain) have been tested before and after proton-irradiation to an equivalent
fluence of about cm (1 MeV
equivalent neutrons). This is the first time that one single collecting
electrode fine pitch 3D sensors are irradiated up to such fluence bump-bonded
to a fine pitch ASIC. The preliminary analysis of the collected data shows no
degradation on the hit detection efficiencies of the tested sensors after high
energy proton irradiation, demonstrating the excellent radiation tolerance of
the 3D pixel sensors. Thus, they will be excellent candidates for the extreme
radiation environment at the innermost layers of the HL-LHC experiments.Comment: Conference Proceedings of VCI2019, 15th Vienna Conference of
Instrumentation, February 18-22, 2019, Vienna, Austria. arXiv admin note:
text overlap with arXiv:1903.0196
A Fe2+-dependent self-inhibited state influences the druggability of human collagen lysyl hydroxylase (LH/PLOD) enzymes
Multifunctional human collagen lysyl hydroxylase (LH/PLOD) enzymes catalyze post-translational hydroxylation and subsequent glycosylation of collagens, enabling their maturation and supramolecular organization in the extracellular matrix (ECM). Recently, the overexpression of LH/PLODs in the tumor microenvironment results in abnormal accumulation of these collagen post-translational modifications, which has been correlated with increased metastatic progression of a wide variety of solid tumors. These observations make LH/PLODs excellent candidates for prospective treatment of aggressive cancers. The recent years have witnessed significant research efforts to facilitate drug discovery on LH/PLODs, including molecular structure characterizations and development of reliable high-throughput enzymatic assays. Using a combination of biochemistry and in silico studies, we characterized the dual role of Fe2+ as simultaneous cofactor and inhibitor of lysyl hydroxylase activity and studied the effect of a promiscuous Fe2+ chelating agent, 2,2'-bipyridil, broadly considered a lysyl hydroxylase inhibitor. We found that at low concentrations, 2,2'-bipyridil unexpectedly enhances the LH enzymatic activity by reducing the inhibitory effect of excess Fe2+. Together, our results show a fine balance between Fe2+-dependent enzymatic activity and Fe2+-induced self-inhibited states, highlighting exquisite differences between LH/PLODs and related Fe2+, 2-oxoglutarate dioxygenases and suggesting that conventional structure-based approaches may not be suited for successful inhibitor development. These insights address outstanding questions regarding druggability of LH/PLOD lysyl hydroxylase catalytic site and provide a solid ground for upcoming drug discovery and screening campaigns
Thromboembolic event rate in paroxysmal and persistent atrial fibrillation: Data from the GISSI-AF trial
BACKGROUND: Few data on the thromboembolic (TE) risk of paroxysmal and persistent atrial fibrillation (AF) are available. This study aimed to assess the incidence of TE events in paroxysmal and persistent AF. METHODS: We performed a subset post hoc analysis of 771 patients with paroxysmal and 463 with persistent AF enrolled in the multicenter, prospective, randomized, double-blind, placebo-controlled GISSI-AF trial - comparing the efficacy of valsartan versus placebo in preventing AF recurrences – where the choice of antithrombotic treatment was left to the judgment of the referring physician. TE and major outcome events were centrally validated. AF recurrences were detected by frequent clinic visits and a transtelephonic monitoring device with weekly and symptomatic transmissions. RESULTS: Eighty-five percent of patients had a history of hypertension, and the 7.7% had heart failure, left ventricular dysfunction, or both. The mean CHADS(2) score was 1.41±0.84. TE and major bleeding events were observed at a low incidence among the overall population at 1-year follow-up (0.97% and 0.81%, respectively). The univariate and multivariable analyses revealed no statistically significant differences in the incidence of TE, major bleeding events or mortality in paroxysmal and persistent AF patients. TE events were more common among women than men (p=0.02). The follow-up examination showed under- or overtreatment with warfarin in many patients, according to guideline suggestions. Warfarin was more frequently prescribed to patients with persistent AF (p<0.0001) and patients with AF recurrences (p<0.0001). AF recurrences were noninvasively detected in 632 (51.2%) patients. In patients without AF recurrences, the TE event rate was 0.5% versus 1.74%, 1.28%, and 1.18% for those with only symptomatic, only asymptomatic or both symptomatic and asymptomatic AF recurrences, respectively, but the difference was not statistically significant, even after adjusting for warfarin treatment and the CHADS(2) score (HR 2.93; CI 95%; 0.8-10.9; p=0.11). CONCLUSIONS: TE and major bleeding events showed a very low incidence in the GISSI-AF trial population, despite under- or overtreatment with warfarin in many patients. TE events had a similar rate in paroxysmal and persistent AF. TRIAL REGISTRATION: Trial registration number: NCT0037627
TLR-4 and VEGF polymorphisms in chronic periaortitis
Chronic periaortitis (CP) is a rare disease that is characterised by fibro-inflammatory tissue surrounding the abdominal aorta and has both non-aneurysmal (idiopathic retroperitoneal fibrosis [IRF]) and aneurysmal forms (inflammatory abdominal aortic aneurysm [IAAA]). We investigated whether toll-like receptor 4 (TLR-4) and vascular endothelial growth factor (VEGF) polymorphisms were associated with susceptibility to, and the clinical features of CP
Syrosingopine sensitizes cancer cells to killing by metformin
We report that the anticancer activity of the widely used diabetic drug metformin is strongly potentiated by syrosingopine. Synthetic lethality elicited by combining the two drugs is synergistic and specific to transformed cells. This effect is unrelated to syrosingopine's known role as an inhibitor of the vesicular monoamine transporters. Syrosingopine binds to the glycolytic enzyme α-enolase in vitro, and the expression of the γ-enolase isoform correlates with nonresponsiveness to the drug combination. Syrosingopine sensitized cancer cells to metformin and its more potent derivative phenformin far below the individual toxic threshold of each compound. Thus, combining syrosingopine and codrugs is a promising therapeutic strategy for clinical application for the treatment of cancer
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