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This study was designed to investigate the indirect neuroprotective properties of recombinant human erythropoietin (rhEPO) pretreatment in a rat model of transient middle cerebral artery occlusion (MCAO).

Abstract Background Animal models of focal cerebral ischemia are widely used in stroke research. The purpose of our study was to evaluate and compare the cerebral macro- and microvascular architecture of rats in two different models of permanent middle cerebral artery occlusion using an innovative quantitative micro- and nano-CT imaging technique. Methods 4h of middle cerebral artery occlusion was performed in rats using the macrosphere method or the suture technique. After contrast perfusion, brains were isolated and scanned en-bloc using micro-CT (8 μm)3 or nano-CT at 500 nm3 voxel size to generate 3D images of the cerebral vasculature. The arterial vascular volume fraction and gray scale attenuation was determined and the significance of differences in measurements was tested with analysis of variance [ANOVA]. Results Micro-CT provided quantitative information on vascular morphology. Micro- and nano-CT proved to visualize and differentiate vascular occlusion territories performed in both models of cerebral ischemia. The suture technique leads to a remarkable decrease in the intravascular volume fraction of the middle cerebral artery perfusion territory. Blocking the medial cerebral artery with macrospheres, the vascular volume fraction of the involved hemisphere decreased significantly (p < 0.001), independently of the number of macrospheres, and was comparable to the suture method. We established gray scale measurements by which focal cerebral ischemia could be radiographically categorized (p < 0.001). Nano-CT imaging demonstrates collateral perfusion related to different occluded vessel territories after macrosphere perfusion. Conclusion Micro- and Nano-CT imaging is feasible for analysis and differentiation of different models of focal cerebral ischemia in rats.

Purpose Patients undergoing cardiac surgery often develop delirium which increases the risk of postoperative morbidity and leads to a reduced quality of life. Retrospective studies show a higher incidence of delirium in patients with seizures. However, these studies do not systematically detect subclinical seizures, so the incidence of seizures after cardiac surgery remains speculative. The objective of this study is to determine the prevalence of electrographic seizures after elective open-chamber cardiac surgery. Methods This prospective, blinded, monocentric, observational study investigated patients scheduled for elective open-chamber valve reconstruction or replacement. Anaesthesia, surgery and postoperative treatment were standardized and not influenced by the presented observation. After surgery, all patients arrived at the ICU, and EEG monitoring started within the first hour. EEG recording was continuously performed for up to 24 h, and the results were independently analysed by two blinded EEG board-certified neurologists. Results 100 patients were included. Abnormal EEG patterns were present in 33% of patients, and 9% of all patients showed electrographic seizures. The main EEG activity at the beginning of each recording was suppressed or showed a burst-suppression pattern, and at the end of recording, all patients had an alpha/theta rhythm. An association between electrographic seizures and delirium was found (p.sub.[chi]2 < 0.01). Conclusion This study reveals a surprisingly high incidence of abnormal EEG patterns and electrographic seizures in patients undergoing open-chamber cardiac surgery. As electrographic seizures are associated with the incidence of delirium, this finding is a relevant phenomenon in the post-cardiac surgery ICU population., Author(s): Marlene Tschernatsch [sup.1] [sup.2] [sup.3], Martin Juenemann [sup.1] [sup.2], Fouad Alhaidar [sup.4], Jasmin El Shazly [sup.1], Marius Butz [sup.1] [sup.2], Marco Meyer [sup.5], Tibo Gerriets [sup.1] [sup.2] [sup.3], Markus [...]

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1552-6569.2008.00250.x Byline: Erwin Stolz (1), Bettina C Fox (1), Oskar Hoffmann (1), Tibo Gerriets (1), Franz Blaes (1), Jorg Kraus (1), Manfred Kaps (1) Keywords: Ultrasound; Autoregulation; Lower body positive pressure; Lower body negative pressure; Head tilt; Cerebral veins Abstract: ABSTRACT BACKGROUND Although there exists a large body of knowledge on the regulation of arterial cerebral hemodynamics, little is known about the cerebral venous outflow (CVO). METHODS In 19 healthy volunteers, the middle cerebral artery and the straight sinus were examined using transcranial Doppler sonography. Arterial and venous mean flow velocities (aFV.sub.mean, vFV.sub.mean, respectively) were registered continuously while applying lower body positive (LBPP) or negative (LBNP) pressure of 30 mmHg and performing head-down (-20[degrees], HDT) and -up (+30[degrees], HUT) tilt manoeuvres. The arterial blood pressure was registered simultaneously with a noninvasive finger blood pressure monitor. Relative changes in parameters compared to the proceeding no-pressure, no-tilt baseline were used for analysis. RESULTS While aFV.sub.mean did not change significantly, vFV.sub.mean inc reased during LBPP by 10.5 [+ or -] 2.9% and decreased during LBNP by 15.1 [+ or -] 3.5% (mean [+ or -] standard error of mean [SEM], P < .01). HUT resulted in a decrease in vFV.sub.mean by 25.5 [+ or -] 3.3% and HDT, in an increase by 7.8 [+ or -] 3.2% (P < .01) without alteration in aFV.sub.mean. This may imply a decrease of cerebral blood volume (CBV) during LBPP and HDT and an increase during LBNP and HUT. CONCLUSIONS CVO cannot be neglected when studying cerebral hemodynamics because it might affect the CBV. Author Affiliation: (1)Department of Neurology, Justus-Liebig-University, Giessen, Germany (ES, BCF, TG, FB, MK); University of Applied Sciences, Giessen, Germany (OH); and Paracelsus Medical University, Christian-Doppler-Clinic, Salzburg, Austria (JK). Article History: Acceptance: Received December 18, 2007, and in revised form December 18, 2007. Accepted for publication January 28, 2008. Article note: Correspondence: Address correspondence to Erwin Stolz, MD, PhD, Department of Neurology, Justus-Liebig-University, Am Steg 14, D-35385 Giessen, Germany. E-mail: erwin.stolz@neuro.med.uni-giessen.de.