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Search Results: 1 - 10 of 10235 matches for " Stefan Schwab "
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Therapeutic hypothermia decreases growth of perihemorrhagic edema and prevents critical increase of intracranial pressure in large intracerebral haemorrhage
Rainer Kollmar, Stefan Schwab, Dimitre Staykov
Critical Care , 2012, DOI: 10.1186/cc11272
Abstract: All patients with large ICH were treated by a detailed institutional protocol that is in line with our ongoing prospective study [7]. Patients aged over 18 years with primary ICH at the level of the basal ganglia or thalamus and a hematoma volume of over 25 ml on initial CCT were treated by TH. Patients have been treated within the first 12 hours after symptom onset if they had a score on the Glasgow Coma Scale (GCS) of ≤8 at presentation or early worsening by 2 points with subsequent endotracheal intubation and neurointensive care treatment. All patients received invasive ICP measurement by external ventricular drainage or a parenchymal probe. Relatives were informed about the treatment and approved this regimen. Patients have not been treated by TH if any clinical signs of herniation such as pupillomotoric defects or bilateral signs of the pyramidal tract at baseline could be observed or the treating team agreed to a do-not-resuscitate order. Laboratory exclusion criteria included an international normalized ratio >1.5, a thrombocyte count below 70,000/μl or leukocytosis >20,000/μl on admission. The presence of intraventricular hemorrhage has not been an exclusion criterion, since we have a standardized protocol, including external ventricular drainage, intraventricular clot lysis and the use of lumbar drainage. Patients who have been randomized to the control arm of our multicenter randomized controlled trial CINCH [7] are not reported here.Patients were treated with an endovascular catheter-based cooling system (ICY catheter; Zoll Medical, USA) positioned in the femoral vein as described previously [5]. The target temperature has been set to 35.0°C. The body core temperature has been measured by a urinary bladder catheter. As soon as body core temperature drops below 36.0°C, patients are covered by a warming blanket to avoid shivering. Ten days after initiation of TH, patients received slowly, controlled rewarming by 0.1°C/hour. The catheter has been changed at
Mild hypothermia of 34°C reduces side effects of rt-PA treatment after thromboembolic stroke in rats
Bernd Kallmünzer, Stefan Schwab, Rainer Kollmar
Experimental & Translational Stroke Medicine , 2012, DOI: 10.1186/2040-7378-4-3
Abstract: Male Wistar rats (n = 48) were subjected to TE. The following treatment groups were investigated: control group - normothermia (37°C); thrombolysis group - rt-PA 90 min after TE; hypothermia by 34°C applied 1.5 to 5 hours after TE; combination therapy- hypothermia and rt-PA. After 24 hours infarct size, brain edema and neuroscore were assessed. Protein markers for inflammation and adhesion, gelatinase activity, and blood brain barrier (BBB) disruption were determined. MRI-measurements investigated infarct evolution and blood flow parameters.The infarct volume and brain swelling were smaller in the hypothermia group compared to the other groups (p < 0.05 to p < 0.01). Thrombolysis resulted in larger infarct and brain swelling than all others. Hypothermia in combination with thrombolysis reduced these parameters compared to thrombolysis (p < 0.05). Moreover, the neuroscore improved in the hypothermia group compared to control and thrombolysis. Animals of the combination therapy performed better than after thrombolysis alone (p < 0.05). Lower serum concentration of sICAM-1, and TIMP-1 were shown for hypothermia and combination therapy. Gelatinase activity was decreased by hypothermia in both groups.Therapeutic hypothermia reduced side-effects of rt-PA associated treatment and reperfusion in our model of TE.Thrombolysis by recombinant tissue-plasminogen activator (rt-PA) is the preferable causal therapy for acute ischemic stroke, but only a minority of all stroke patients is eligible for treatment [1]. Its approval is restricted to the first 4.5 hours after symptom onset [2,3]. Delayed administration of rt-PA has less pronounced effects on restoration of cerebral blood flow (CBF) and outcome, but may still be effective [2-4]. However, clinical and animal data suggest an increased risk for intracerebral hemorrhage and brain edema after delayed thrombolysis [4,5]. Possibly, these side effects account to a reperfusion-associated injury [6], pro-apoptotic and neurotoxic sid
On Puzzles and Non-Puzzles in B -> pi pi, pi K Decays
Fleischer, Robert;Recksiegel, Stefan;Schwab, Felix
High Energy Physics - Phenomenology , 2007, DOI: 10.1140/epjc/s10052-007-0277-8
Abstract: Recently, we have seen interesting progress in the exploration of CP violation in B^0_d -> pi^+ pi^-: the measurements of mixing-induced CP violation by the BaBar and Belle collaborations are now in good agreement with each other, whereas the picture of direct CP violation is still unclear. Using the branching ratio and direct CP asymmetry of B^0_d -> pi^- K^+, this situation can be clarified. We predict A_CP^dir(B_d -> pi^+ pi^-) = -0.24+-0.04, which favours the BaBar result, and extract gamma=(70.0^{+3.8}_{-4.3})deg, which agrees with the unitarity triangle fits. Extending our analysis to other B -> pi K modes and B^0_s -> K^+ K^- with the help of the SU(3) flavour symmetry and plausible dynamical assumptions, we find that all observables with colour-suppressed electroweak penguin contributions are measured in excellent agreement with the Standard Model. As far as the ratios R_{c,n} of the charged and neutral B -> pi K branching ratios are concerned, which are sizeably affected by electroweak penguin contributions, our Standard-Model predictions have almost unchanged central values, but significantly reduced errors. Since the new data have moved quite a bit towards these results, the "B -> pi K puzzle" for the CP-conserving quantities has been significantly reduced. However, the mixing-induced CP violation of B^0_d -> pi^0 K_S does look puzzling; if confirmed by future measurements, this effect could be accommodated through a modified electroweak penguin sector with a large CP-violating new-physics phase. Finally, we point out that the established difference between the direct CP asymmetries of B^+- -> pi^0 K^+- and B_d -> pi^-+ K^+- appears to be generated by hadronic and not by new physics.
Inverse Problem on Heat Conduction in Heterogeneous Medium  [PDF]
Albert Schwab
American Journal of Computational Mathematics (AJCM) , 2014, DOI: 10.4236/ajcm.2014.41003
Abstract:

Under consideration is a nonclassical stationary problem on heat conduction in a body with the pre-set surface temperature and heat flow. The body contains inclusions at unknown locations and with unknown boundaries. The body and inclusions have different constant thermal conductivities. The author explores the possibility of locating inclusions. The article presents an integral criterion based on which a few statements on identification of inclusions in a body are proved.

G-CSF, rt-PA and combination therapy after experimental thromboembolic stroke
Rainer Kollmar, Nils Henninger, Christian Urbanek, Stefan Schwab
Experimental & Translational Stroke Medicine , 2010, DOI: 10.1186/2040-7378-2-9
Abstract: Male Wistar rats (n = 72) were subjected to a model of thromboembolic occlusion (TE) of the middle cerebral artery. Different groups (n = 12 each) treated by recombinant tissue-plasminogen activator (rt-PA) or/and G-CSF: group control (control), group early G-CSF (G-CSF 60 min after TE), group rt-PA (rt-PA 60 min after TE), group com (combination rt-PA/G-CSF), group delayed rt-PA (rt-PA after 180 min), group deco (G-CSF after 60 min, rt-PA after 180 min). Animals were investigated by magnetic resonance imaging (MRI) and silver infarct staining (SIS) 24 hours after TE.Early G-CSF or rt-PA reduced the infarct size compared to all groups (p < 0.05 to p < 0.01) with the exception of group com, (p = n.s.) as measured by T2, DWI, and SIS. Late administration of rt-PA lead to high mortality and larger infarcts compared to all other groups (p < 0.05 to p < 0.01). Pre-treatment by G-CSF (deco) reduced infarct site compared to delayed rt-PA treatment (p < 0.05). G-CSF did not significantly influence PWI when combined with rt-PA. All animals treated by rt-PA showed improved parameters in PWI indicating reperfusion.G-CSF was neuroprotective when given early after TE. Early combination with rt-PA showed no additional benefit compared to rt-PA or G-CSF alone, but did not lead to side effects. Pretreatment by G-CSF was able to reduce deleterious effects of late rt-PA treatment.Granulocyte Colony-Stimulating Factor (G-CSF) is neuroprotective in models of acute experimental cerebral ischemia [1-9]. During the acute phase of ischemic stroke, various neuroprotective effects of G-CSF have been described in different species [1,2,9]. G-CSF influences apoptotic pathways [3,4], suppresses edema formation and interleukin-1 beta expression [1,6] induces the cerebral G-CSF receptor [7], and diminishes glutamate induced neurotoxicity [1,10]. Moreover, reduction of infarct size is associated with an improved functional score [6,8,11]. Remarkably, G-CSF reduced the infarct size even when given
Current Density Functional Theory for one-dimensional fermions
Michael Dzierzawa,Ulrich Eckern,Stefan Schenk,Peter Schwab
Physics , 2008, DOI: 10.1002/pssb.200881554
Abstract: The frequency-dependent response of a one-dimensional fermion system is investigated using Current Density Functional Theory (CDFT) within the local approximation (LDA). DFT-LDA, and in particular CDFT-LDA, reproduces very well the dispersion of the collective excitations. Unsurprisingly, however, the approximation fails for details of the dynamic response for large wavevectors. In particular, we introduce CDFT for the one-dimensional spinless fermion model with nearest-neighbor interaction, and use CDFT-LDA plus exact (Bethe ansatz) results for the groundstate energy as function of particle density and boundary phase to determine the linear response. The successes and failures of this approach are discussed in detail.
Successes and failures of Bethe Ansatz Density Functional Theory
Stefan Schenk,Michael Dzierzawa,Peter Schwab,Ulrich Eckern
Physics , 2008, DOI: 10.1103/PhysRevB.78.165102
Abstract: The response of a one-dimensional fermion system is investigated using Density Functional Theory (DFT) within the Local Density Approximation (LDA), and compared with exact results. It is shown that DFT-LDA reproduces surprisingly well some of the characteristic features of the Luttinger liquid, namely the vanishing spectral weight of low energy particle-hole excitations, as well as the dispersion of the collective charge excitations. On the other hand, the approximation fails, even qualitatively, for quantities for which backscattering is important, i.e., those quantities which are crucial for an accurate description of transport. In particular, the Drude weight in the presence of a single impurity is discussed.
EARLYDRAIN- outcome after early lumbar CSF-drainage in aneurysmal subarachnoid hemorrhage: study protocol for a randomized controlled trial
Jürgen Bardutzky, Jens Witsch, Eric Jüttler, Stefan Schwab, Peter Vajkoczy, Stefan Wolf
Trials , 2011, DOI: 10.1186/1745-6215-12-203
Abstract: In retrospective trials lumbar drainage of cerebrospinal fluid has been shown to be a safe and feasible measure to remove the blood from the basal cisterns and decrease the incidence of delayed cerebral ischemia and vasospasm in the respective study populations. However, the efficacy of lumbar drainage has not been evaluated prospectively in a randomized controlled trial yet.This is a protocol for a 2-arm randomized controlled trial to compare an intervention group receiving early continuous lumbar CSF-drainage and standard neurointensive care to a control group receiving standard neurointensive care only. Adults suffering from a first aneurysmal subarachnoid hemorrhage whose aneurysm has been secured by means of coiling or clipping are eligible for trial participation. The effect of early CSF drainage (starting < 72 h after securing the aneurysm) will be measured in the following ways: the primary endpoint will be disability after 6 months, assessed by a blinded investigator during a personal visit or standardized telephone interview using the modified Rankin Scale. Secondary endpoints include mortality after 6 months, angiographic vasospasm, transcranial Doppler sonography (TCD) mean flow velocity in both middle cerebral arteries and rate of shunt insertion at 6 months after hospital discharge.Here, we present the study design of a multicenter prospective randomized controlled trial to investigate whether early application of a lumbar drainage improves clinical outcome after aneurysmal subarachnoid hemorrhage.www.clinicaltrials.gov Identifier: NCT01258257Non-traumatic subarachnoid hemorrhage (SAH) is a major cause of stroke accounting for approximately 1-7% of cases. In 80% of SAH-cases the source of bleeding is a ruptured cerebral aneurysm [1,2]. Important for a patient's prognosis is the severity of the initial bleeding and complications associated with the presence of blood in the subarachnoid space. Once the aneurysmal SAH has occurred patients are predominant
Learn More about Your Data: A Symbolic Regression Knowledge Representation Framework  [PDF]
Ingo Schwab, Norbert Link
International Journal of Intelligence Science (IJIS) , 2012, DOI: 10.4236/ijis.2012.224018
Abstract: In this paper, we propose a flexible knowledge representation framework which utilizes Symbolic Regression to learn and mathematical expressions to represent the knowledge to be captured from data. In this approach, learning algorithms are used to generate new insights which can be added to domain knowledge bases supporting again symbolic regression. This is used for the generalization of the well-known regression analysis to fulfill supervised classification. The approach aims to produce a learning model which best separates the class members of a labeled training set. The class boundaries are given by a separation surface which is represented by the level set of a model function. The separation boundary is defined by the respective equation. In our symbolic approach, the learned knowledge model is represented by mathematical formulas and it is composed of an optimum set of expressions of a given superset. We show that this property gives human experts options to gain additional insights into the application domain. Furthermore, the representation in terms of mathematical formulas (e.g., the analytical model and its first and second derivative) adds additional value to the classifier and enables to answer questions, which sub-symbolic classifier approaches cannot. The symbolic representation of the models enables an interpretation by human experts. Existing and previously known expert knowledge can be added to the developed knowledge representation framework or it can be used as constraints. Additionally, the knowledge acquisition framework can be repeated several times. In each step, new insights from the search process can be added to the knowledge base to improve the overall performance of the proposed learning algorithms.
Glatiramer Acetate Treatment Normalizes Deregulated microRNA Expression in Relapsing Remitting Multiple Sclerosis
Anne Waschbisch, Monika Atiya, Ralf A. Linker, Sergej Potapov, Stefan Schwab, Tobias Derfuss
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024604
Abstract: The expression of selected microRNAs (miRNAs) known to be involved in the regulation of immune responses was analyzed in 74 patients with relapsing remitting multiple sclerosis (RRMS) and 32 healthy controls. Four miRNAs (miR-326, miR-155, miR-146a, miR-142-3p) were aberrantly expressed in peripheral blood mononuclear cells from RRMS patients compared to controls. Although expression of these selected miRNAs did not differ between treatment-na?ve (n = 36) and interferon-beta treated RRMS patients (n = 18), expression of miR-146a and miR-142-3p was significantly lower in glatiramer acetate (GA) treated RRMS patients (n = 20) suggesting that GA, at least in part, restores the expression of deregulated miRNAs in MS.
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