Browsing by Subject "SHOCK"

Sort by: Order: Results:

Now showing items 21-25 of 25
  • Vaara, Suvi T.; Hollmen, Maija; Korhonen, Anna-Maija; Maksimow, Mikael; Ala-Kokko, Tero; Salmi, Marko; Jalkanen, Sirpa; Pettilä, Ville; FINNAKI Study Grp (2016)
    Background CD73 dephosphorylates adenosine monophosphate to adenosine that is an anti-inflammatory molecule inhibiting immune activation and vascular leakage. Therefore, CD73 could be an interesting mediator both in sepsis and acute kidney injury (AKI). We aimed to explore the soluble CD73 (sCD73) levels and their evolution in critically ill patients with severe sepsis and, second, to scrutinize the potential association of sCD73 levels with AKI and 90-day mortality. Methods This was a post-hoc laboratory analysis of the prospective, observational FINNAKI study conducted in 17 Finnish ICU during 5 months in 2011-2012. Plasma samples of 588 patients admitted with severe sepsis/shock or with developing severe sepsis were analyzed at 0h (ICU admission) and 24h, and additionally, on day 3 or day 5 from a subset of the patients. Results The median [IQR] sCD73 levels at 0h were 5.11 [3.29-8.28] ng/mL and they decreased significantly from 0h to 4.14 [2.88-7.11] ng/mL at 24h, P Conclusions Compared to normal population, the sCD73 levels were generally low at 0h, showed a decrease to 24h, and later an increase by day 5. The sCD73 levels do not seem useful in predicting the development of AKI or 90-day mortality among patients with severe sepsis or shock.
  • Wijsen, N.; Aran, A.; Sanahuja, B.; Pomoell, J.; Poedts, S. (2020)
    Aims. We study the effect of the magnetic gradient and curvature drifts on the pitch-angle dependent transport of solar energetic particles (SEPs) in the heliosphere, focussing on similar to 3-36 MeV protons. By considering observers located at different positions in the heliosphere, we investigate how drifts may alter the measured intensity-time profiles and energy spectra. We focus on the decay phase of solar energetic proton events in which a temporal invariant spectrum and disappearing spatial intensity gradients are often observed; a phenomenon known as the "reservoir effect" or the "SEP flood". We study the effects of drifts by propagating particles both in nominal and non-nominal solar wind conditions.Methods. We used a three-dimensional (3D) particle transport model, solving the focused transport equation extended with the effect of particle drifts in the spatial term. Nominal Parker solar wind configurations of different speeds and a magnetohydrodynamic (MHD) generated solar wind containing a corotating interaction region (CIR) were considered. The latter configuration gives rise to a magnetic bottle structure, with one bottleneck at the Sun and the other at the CIR. We inject protons from a fixed source at 0.1 AU, the inner boundary of the MHD model.Results. When the drift induced particle net-flux is zero, the modelled intensity-time profiles obtained at different radial distances along an IMF line show the same intensity fall-off after the prompt phase of the particle event, which is in accordance with the SEP flood phenomenon. However, observers magnetically connected close to the edges of the particle injection site can experience, as a result of drifts, a sudden drop in the intensities occurring at different times for different energies such that no SEP flood phenomenon is established. In the magnetic bottle structure, this effect is enhanced due to the presence of magnetic field gradients strengthening the nominal particle drifts. Moreover, anisotropies can be large for observers that only receive particles through drifts, illustrating the importance of pitch-angle dependent 3D particle modelling. We observe that interplanetary cross-field diffusion can mitigate the effects of particle drifts.Conclusions. Particle drifts can substantially modify the decay phase of SEP events, especially if the solar wind contains compression regions or shock waves where the drifts are enhanced. This is, for example, the case for our CIR solar wind configuration generated with a 3D MHD model, where the effect of drifts is strong. A similar decay rate in different energy channels and for different observers requires the mitigation of the effect of drifts. One way to accomplish this is through interplanetary cross-field diffusion, suggesting thus a way to determine a minimum value for the cross-field diffusion strength.
  • Strand, Kristian; Søreide, Eldar; Kirkegaard, Hans; Taccone, Fabio Silvio; Grejs, Anders Morten; Duez, Christophe Henri Valdemar; Jeppesen, Anni Nørgaard; Storm, Christian; Rasmussen, Bodil Steen; Laitio, Timo; Hassager, Christian; Toome, Valdo; Hästbacka, Johanna; Skrifvars, Markus B (2020)
    Background Acute kidney injury (AKI) is common after cardiac arrest and targeted temperature management (TTM). The impact of different lengths of cooling on the development of AKI has not been well studied. In this study of patients included in a randomised controlled trial of TTM at 33°C for 24 versus 48hours after cardiac arrest (TTH48 trial), we examined the influence of prolonged TTM on AKI and the incidence and factors associated with the development of AKI. We also examined the impact of AKI on survival. Methods This study was a sub-study of the TTH48 trial, which included patients cooled to 33±1˚C after out-of-hospital cardiac arrest for 24 versus 48hours. AKI was classified according to the KDIGO AKI criteria based on serum creatinine and urine output collected until ICU discharge for a maximum of seven days. Survival was followed for up to six months. The association of admission factors on AKI was analysed with multivariate analysis and the association of AKI on mortality was analysed with Cox regression using the time to AKI as a time-dependent covariate. Results Of the 349 patients included in the study, 159 (45.5%) developed AKI. There was no significant difference in the incidence, severity or time to AKI between the 24- and 48-hour groups. Serum creatinine values had significantly different trajectories for the two groups with a sharp rise occurring during rewarming. Age, time to return of spontaneous circulation, serum creatinine at admission and body mass index were independent predictors of AKI. Patients with AKI had a higher mortality than patients without AKI (hospital mortality 36.5% vs 12.5%, p
  • Morosan, D. E.; Palmerio, E.; Pomoell, J.; Vainio, R.; Palmroth, M.; Kilpua, E. K. J. (2020)
    Context. Some of the most prominent sources for particle acceleration in our Solar System are large eruptions of magnetised plasma from the Sun called coronal mass ejections (CMEs). These accelerated particles can generate radio emission through various mechanisms. Aims. CMEs are often accompanied by a variety of solar radio bursts with different shapes and characteristics in dynamic spectra. Radio bursts directly associated with CMEs often show movement in the direction of CME expansion. Here, we aim to determine the emission mechanism of multiple moving radio bursts that accompanied a flare and CME that took place on 14 June 2012. Methods. We used radio imaging from the Nancay Radioheliograph, combined with observations from the Solar Dynamics Observatory and Solar Terrestrial Relations Observatory spacecraft, to analyse these moving radio bursts in order to determine their emission mechanism and three-dimensional (3D) location with respect to the expanding CME. Results. In using a 3D representation of the particle acceleration locations in relation to the overlying coronal magnetic field and the CME propagation, for the first time, we provide evidence that these moving radio bursts originate near the CME flanks and that some are possible signatures of shock-accelerated electrons following the fast CME expansion in the low corona. Conclusions. The moving radio bursts, as well as other stationary bursts observed during the eruption, occur simultaneously with a type IV continuum in dynamic spectra, which is not usually associated with emission at the CME flanks. Our results show that moving radio bursts that could traditionally be classified as moving type IVs can represent shock signatures associated with CME flanks or plasma emission inside the CME behind its flanks, which are closely related to the lateral expansion of the CME in the low corona. In addition, the acceleration of electrons generating this radio emission appears to be favoured at the CME flanks, where the CME encounters coronal streamers and open field regions.
  • Vaara, Suvi T.; Lakkisto, Paivi; Immonen, Katariina; Tikkanen, Ilkka; Ala-Kokko, Tero; Pettila, Ville; FINNAKI Study Grp (2016)
    Background Apoptosis is a key mechanism involved in ischemic acute kidney injury (AKI), but its role in septic AKI is controversial. Biomarkers indicative of apoptosis could potentially detect developing AKI prior to its clinical diagnosis. Methods As a part of the multicenter, observational FINNAKI study, we performed a pilot study among critically ill patients who developed AKI (n = 30) matched to critically ill patients without AKI (n = 30). We explored the urine and plasma levels of cytokeratin-18 neoepitope M30 (CK-18 M30), cell-free DNA, and heat shock protein 70 (HSP70) at intensive care unit (ICU) admission and 24h thereafter, before the clinical diagnosis of AKI defined by the Kidney Disease: Improving Global Outcomes - creatinine and urine output criteria. Furthermore, we performed a validation study in 197 consecutive patients in the FINNAKI cohort and analyzed the urine sample at ICU admission for CK-18 M30 levels. Results In the pilot study, the urine or plasma levels of measured biomarkers at ICU admission, at 24h, or their maximum value did not differ significantly between AKI and non-AKI patients. Among 20 AKI patients without severe sepsis, the urine CK-18 M30 levels were significantly higher at 24h (median 116.0, IQR [32.3-233.0] U/L) than among those 20 patients who did not develop AKI (46.0 [0.0-54.0] U/L), P = 0.020. Neither urine cell-free DNA nor HSP70 levels significantly differed between AKI and non-AKI patients regardless of the presence of severe sepsis. In the validation study, urine CK-18 M30 level at ICU admission was not significantly higher among patients developing AKI compared to non-AKI patients regardless of the presence of severe sepsis or CKD. Conclusions Our findings do not support that apoptosis detected with CK-18 M30 level would be useful in assessing the development of AKI in the critically ill. Urine HSP or cell-free DNA levels did not differ between AKI and non-AKI patients.