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Recent evidence suggests axonal injury after aneurysmal subarachnoid haemorrhage (aSAH). The microtubule-associated protein, tau, has been shown to be elevated in the cerebrospinal fluid after aSAH, however, brain extracellular tau levels and their relation to long-term neurological and cognitive outcomes have not been investigated.Serial cerebral microdialysis (CMD) samples were collected from 22 consecutive aSAH patients with multimodal neuromonitoring to determine CMD-total-tau by ELISA. CMD-total-tau was analysed considering other brain metabolic parameters, brain tissue oxygen tension (PbtO2), and functional and neuropsychological outcome at 12 months. All outcome models were analysed using generalised estimating equations with an autoregressive working correlation matrix to account for multiple measurements of brain extracellular proteins per subject.CMD-total-tau levels positively correlated with brain extracellular fluid levels of lactate (r=0.40, p0.001), glutamate (r=0.45, p0.001), pyruvate (r=0.26, p0.001), and the lactate-pyruvate ratio (r=0.26, p0.001), and were higher in episodes of hypoxic (PbtO220 mm Hg) brain extracellular lactate elevation (4 mmol/L) (p0.01). More importantly, high CMD-total-tau levels were associated with poor functional outcome (modified Rankin Scale ≥4) 12 months after aSAH even after adjusting for disease severity and age (p=0.001). A similar association was found with 3/5 neuropsychological tests indicative of impairments in cognition, psychomotor speed, visual conceptualisation and frontal executive functions at 1 year after aSAH (p0.01).These results suggest that CMD-total tau may be an important biomarker for predicting long-term outcome in patients with severe aSAH. The value of axonal injury needs further confirmation in a larger patient cohort, preferably combined with advanced imaging techniques.

Alois J. Schiefecker *, Ronny Beer , Josef Steidl , Florian Sohm, Andrea Griesmacher , Alexander K. Brendel , Iris Unterberger , Marlene Fischer , Anelia Dietmann , Bettina Pfausler , Claudius Thome , Erich Schmutzhard , Raimund Helbok a Division of Neurocritical Care, Department of Neurology, Medical University Innsbruck, Austria Central Institute of Medical and Chemical Laboratory Diagnostics, Medical University Innsbruck, Austria Department of Neurosurgery, Medical University Innsbruck, Austria

Brain derived neurotrophic factor (BDNF) is associated with pain modulation and central sensitization. Recently, a role of BDNF in migraine and cluster headache pathophysiology has been suspected due to its known interaction with calcitonin gene-related peptide. Bi-center prospective study was done enrolling four diagnostic groups: episodic migraine with and without aura, episodic cluster headache, frequent episodic tension-type headache, and healthy individuals. In migraineurs, venous blood samples were collected twice: outside and during migraine attacks prior to pain medication. In cluster headache patients serum samples were collected in and outside cluster bout. Analysis of BDNF was performed using enzyme-linked immunosorbent assay technique. Migraine patients revealed significantly higher BDNF serum levels during migraine attacks (n = 25) compared with headachefree intervals (n = 53, P\0.01), patients with tensiontype headache (n = 6, P\0.05), and healthy controls (n = 22, P\0.001). There was no significant difference between patients with migraine with aura compared with those without aura, neither during migraine attacks nor during headache-free periods. Cluster headache patients showed significantly higher BDNF concentrations inside (n = 42) and outside cluster bouts (n = 24) compared with healthy controls (P\0.01, P\0.05). BDNF is increased during migraine attacks, and in cluster headache, further supporting the involvement of BDNF in the pathophysiology of these primary headaches. © The Author(s) 2012.

Background:Cerebral vasospasm (CVS) and cerebral infarction due to vasospasm (CIV) are major complications after spontaneous subarachnoid hemorrhage (SAH). Alteration of vasomotor tone has been postulated as an important factor in the pathogenesis of CVS. Members of the transforming growth factor-β (TGF-β) family and their receptors have been implicated in the regulation of vascular tone. Methods:Serum levels of soluble endoglin (sEng) and plasma levels of TGF-β1 of 20 consecutive SAH patients were analyzed within 15 days after SAH using ELISA and correlated with CVS, CIV and outcome. Twenty voluntary age- and sex-matched blood donors served as healthy controls (HCs). Results:SAH patients showed significantly lower sEng serum levels and higher TGF-β1 plasma levels compared to HCs. Patients who developed Doppler sonographic CVS (dCVS) had significantly higher TGF-β1 levels. Patients with CIV and patients with hydrocephalus showed significantly lower sEng levels. On day 3, pSAH sEng levels below 3.88 ng/ml or TGF-β1 levels higher than 7.2 ng/ml had a predictive value for the development of CIV. Low mean sEng levels over the study period were highly predictive of poor long-term functional outcome (modified Rankin Scale ≧2) at 6 months after SAH. Conclusions:Concentrations of the vasoactive factors sEng in serum and TGF-β1 in plasma are significantly altered in SAH patients compared to HCs. The results of this pilot study indicate that sEng could represent a novel prognostic biomarker for the onset of secondary complications and long-term functional outcome after SAH.

OBJECTIVE To evaluate the pathophysiologic changes in the inner ear during the course of severe cerebral malaria in an established animal model, C57 BL/6J mice. METHODS This study aims to examine the hearing threshold, the histological changes and ICAM-1 expression in the murine cochlea. RESULTS Four of seven mice showed an expected hearing loss of 20 dB or more. The light microscopy of the inner ear did not show any morphologic alterations. The immunohistochemical analysis for ICAM-1 showed intensive staining in the stria vascularis of sick animals and hardly any reaction in healthy controls. CONCLUSION The up-regulation of ICAM-1 in the stria vascularis - generating the endocochlear potential - suggests its involvement in plasmodial infection.

Little is known about endothelial activation under the influence of endovascular temperature management. This analysis was designed to measure the endothelial markers Angiopoietin-1 (Ang-1) and -2 (Ang-2) in endovascularly based prophylactic normothermia versus conventional temperature management.In this randomized controlled trial patients with spontaneous subarachnoid or spontaneous intracerebral hemorrhage were prospectively enrolled and randomized in two treatment arms: (a) prophylactic normothermia group with target core temperature 36.5°C using endovascular cooling, (b) active control group with conventional stepwise predefined fever management using antipyretic medication and surface cooling. Blood samples were obtained on days 1, 4, and 7. In a substudy Ang-1 and -2 were measured in 63 patients for whom samples on consecutive days were available.The median total fever burden during the course of treatment was 0.0°C and 5.9°C h in the endovascular and the conventional group, respectively (P 0.0001). Angiopoietin serum levels did not yield a statistical difference when comparing the two treatment arms. Ang-1 was significantly lowered, whereas Ang-2 levels were significantly elevated on day 4 compared to baseline levels irrespective of group allocation (P 0.0001). The application of non-steroidal anti-inflammatory drugs (NSAIDs) was associated with significantly increased Ang-1 (P 0.05) and lower Ang-2 levels on day 7 (P 0.05).Endovascular long-term temperature management did not alter Ang-1 and -2 levels compared to the control group indicating that the endovascular cooling technique itself does not lead to additional endothelial impairment. However, application of NSAIDs led to lower Ang-2 serum concentrations in the endovascular group.

Background and Purpose— We analyzed the impact of long-term endovascularly based prophylactic normothermia versus conventional temperature management on inflammatory parameters in patients with severe cerebrovascular disease. Methods— This was a prospective, randomized, controlled trial comparing the course of inflammatory parameters between the 2 treatment arms: (1) prophylactically endovascular long-term normothermia; and (2) conventional, stepwise fever management with antiinflammatory drugs and surface cooling. Inclusion criteria were (1) spontaneous subarachnoid hemorrhage with Hunt–Hess grade between 3 and 5; (2) spontaneous intracerebral hemorrhage with a Glasgow Coma Scale score of ≤10; or (3) complicated cerebral infarction requiring intensive care unit treatment with a NIH Stroke Scale score of ≥15. Treatment period was 336 hours in subarachnoid hemorrhage patients and 168 hours in patients with complicated stroke or intracerebral hemorrhage patients. Results— A total of 102 patients (56 female) were enrolled during a 3.5-year period. Overall median total fever burden during the course of treatment was 0.0°C hour and 4.3°C hours in the catheter and conventional group, respectively ( P P P Conclusions— The proinflammatory cytokines C-reactive protein and interleukin-6 were significantly elevated in patients receiving prophylactic endovascularly based long-term normothermia. Nonsteroidal antiinflammatory drugs significantly affected the course of proinflammatory parameters; thus, future trials should investigate the role of nonsteroidal antiinflammatory drugs in severe cerebrovascular disease patients and their interaction with temperature management. Clinical Trial Registration— Trial not registered; enrollment began before July 2005.

Background and Purpose— Spontaneous subarachnoid hemorrhage (SAH) still has a high risk for poor outcome that is frequently attributable to symptomatic cerebral vasospasm (CVS). We hypothesize that cellular microparticles (MP) play a role in the pathogenesis of CVS and may serve as biomarkers for CVS. Methods— In 20 consecutive SAH patients, endothelial, leukocyte, platelet, and erythrocyte MP were measured during 15 days after ictus. CVS was detected by transcranial Doppler sonography. Twenty matched volunteers served as healthy controls. Results— Endothelial, leukocyte, and erythrocyte MP were elevated in SAH patients compared to healthy controls. CD105 + and CD62e + endothelial MP were significantly higher in SAH patients with Doppler sonographic CVS. CD105 + endothelial MP were especially increased on the days of Doppler sonographic CVS onset. In patients experiencing cerebral infarction attributable to vasospasm, CD41 + platelet MP were elevated in addition to endothelial MP. CD41 + platelet MP were significantly higher in patients with any level of disability (modified Rankin Scale score ≥1) compared to those who made a full recovery (modified Rankin Scale score=0) on discharge from hospital. Conclusion— Endothelial MP were elevated in patients with SAH. This elevation coincided with the occurrence of Doppler sonographic CVS and therefore could be a novel biomarker for CVS. Platelet MP might be involved in the pathogenesis of cerebral infarction attributable to vasospasm, resulting in neurological morbidity.

BACKGROUND Molecular mechanisms involved in the pathogenesis of severe Plasmodium falciparum malaria-specifically, cerebral malaria-are still unclear. Transforming growth factor beta (TGF-beta) family members are important regulators of inflammation that influence malaria pathogenesis. The soluble form of the auxiliary receptor endoglin (sEng) may play a role in malaria pathogenesis. METHODS Serum levels of sEng were measured using enzyme-linked immunosorbent-assay in Gabonese children with cerebral malaria (n = 7) severe malaria (n = 43), or uncomplicated malaria (n = 43) and were compared with levels in healthy control subjects (n = 25) and in another infectious disease group (n = 8). RESULTS Serum sEng levels were higher in patients with cerebral malaria and all patients with severe malaria when compared with levels in patients in the other infection group and the healthy control group. Furthermore, sEng correlated significantly with disease severity. Only 7% of patients with uncomplicated malaria and none of the control patients (patients in the other infection group or the healthy control group) had serum levels higher than 12 ng/mL, whereas this was found in 85.7% of patients with cerebral malaria and 46.5% of patients with severe malaria. CONCLUSIONS High sEng levels may attenuate anti-inflammatory response resulting in clinical deterioration of patients with P. falciparum malaria. Our results further corroborate the role of the vascular compartment, especially the endothelium, in severe malaria pathogenesis.

Introduction There is a substantial amount of evidence from animal models that early brain injury (EBI) may play an important role for secondary brain injury after aneurysmal subarachnoid hemorrhage (aSAH). Cerebral microdialysis (CMD) allows online measurement of brain metabolites, including the pro-inflammatory cytokine interleukin-6 (IL-6) and matrix metalloproteinase-9 (MMP-9), which is indicative for disruption of the blood-brain barrier. Methods Twenty-six consecutive poor-grade aSAH patients with multimodal neuromonitoring were analyzed for brain hemodynamic and metabolic changes, including CMD-IL-6 and CMD-MMP-9 levels. Statistical analysis was performed by using a generalized estimating equation with an autoregressive function. Results The baseline cerebral metabolic profile revealed brain metabolic distress and an excitatory response which improved over the following 5 days (P P P P = 0.04), whereas admission disease severity and early brain tissue hypoxia were associated with higher CMD-MMP-9 levels (P P ≤0.01). All models were adjusted for probe location, aneurysm securing procedure, and disease severity as appropriate. Conclusions Multimodal neuromonitoring techniques allow insight into pathophysiologic changes in the early phase after aSAH. The results may be used as endpoints for future interventions targeting EBI in poor-grade aSAH patients.

Introduction Vasospasm still is a major cause of morbidity after aneurysmal subarachnoid hemorrhage. The purpose of this report is to describe the successful management of severe refractory vasospasm with continuous intra-arterial nimodipine (IAN) treatment. Case description A 72-year old right handed woman was admitted with non-traumatic SAH WFNS grade 1. Cerebral computed tomography demonstrated thick blood filling of the basal cisterns, and intraventricular hemorrhage. Cerebral angiogram failed to detect a vascular abnormality. After an uneventful initial course the patient developed symptomatic left middle cerebral artery vasospasm with aphasia and corresponding restriction in diffusion weighted images in the left frontal lobe. Bolus IAN only transiently improved cerebral circulation and clinical signs and symptoms. Continuous-IAN was started and led to full clinical recovery and normalisation of MRI diffusion restrictions. Discussion and conclusions Continuous selective intra-arterial infusion of nimodipine may be an option in selected patients with symptomatic vasospasm refractory to conventional treatment after careful consideration of benefits and procedure-related risks.

Background Triptans are recommended as first-line therapy in the acute phase of a migraine attack. We describe patterns of triptan use in a tertiary care headache outpatient clinic, particularly addressing factors that are associated with triptan discontinuation. Methods From December 2009 until August 2012, demographic and clinical data of consecutive patients with migraine were collected. The Headache Impact Test (HIT-6) was used to measure the adverse impact of headaches. Factors associated with triptan discontinuation were analyzed using binary logistic regression. Results Of 511 migraine patients included, 73.2% (n = 374) were triptan naive on first consultation. At follow-up, 57.1% of new triptan users (n = 72/126) reported pain-freedom or pain relief after 2 hours, 40.5% (n = 51/126) did not refill their triptan, another 15.1% (n = 19/126) switched to a different type of triptan. Negative response to triptan treatment and substantial or severe headache impact (HIT-6 score ≥56) at first follow-up were associated with triptan discontinuation (OR 0.39 [95% CI 0.20—0.78], P = .007; OR 3.33 [95% CI 1.10–10.03], P = .033). Conclusions Although triptans have been in clinical use for more than two decades, many migraine sufferers in our study population were found to be triptan naive on first consultation. The HIT-6 score may be used as an indicator of triptan adherence and help to identify patients at risk for triptan discontinuation.

Background Fever is common in neurocritical care patients and is associated with poor outcome. Targeted temperature management (TTM), i.e. therapeutic hypothermia or controlled normothermia, after acute brain injury has been studied as a neuroprotectant for several decades. In contrast to pharmacological agents with specific targets TTM affects multiple pathophysiological mechanisms and is primarily thought to attenuate secondary brain injury. Most promising results have been obtained from experimental studies on cerebral ischemia or traumatic brain injury showing beneficial effects of hypothermia on structural and functional outcome. Objective The aim of this systematic review of the literature is to provide an overview on preclinical and clinical data on the use of TTM for intracerebral hemorrhage (ICH). The impact of TTM on structural changes and functional outcome after induced and spontaneous ICH will be summarized. Results and discussion A positive influence of hypothermia has been observed in animal models of spontaneous ICH improving, among others, perihematomal edema, blood-brain barrier integrity, inflammation and thrombin-induced injury. However, results regarding functional outcome are conflicting. Little data is available on the effect of TTM after spontaneous ICH in humans. Single-center observational studies have shown reduced perihematomal edema under mild hypothermia and an association with favorable outcome. However, these beneficial effects on mortality and functional outcome have not been confirmed in randomized studies so far. Thus, results from ongoing, prospective randomized-controlled trials are highly anticipated.

Gene transfer into hematopoietic stem cells has been used successfully for correcting lymphoid but not myeloid immunodeficiencies. Here we report on two adults who received gene therapy after nonmyeloablative bone marrow conditioning for the treatment of X-linked chronic granulomatous disease (X-CGD), a primary immunodeficiency caused by a defect in the oxidative antimicrobial activity of phagocytes resulting from mutations in gp91(phox). We detected substantial gene transfer in both individuals' neutrophils that lead to a large number of functionally corrected phagocytes and notable clinical improvement. Large-scale retroviral integration site-distribution analysis showed activating insertions in MDS1-EVI1, PRDM16 or SETBP1 that had influenced regulation of long-term hematopoiesis by expanding gene-corrected myelopoiesis three- to four-fold in both individuals. Although insertional influences have probably reinforced the therapeutic efficacy in this trial, our results suggest that gene therapy in combination with bone marrow conditioning can be successfully used to treat inherited diseases affecting the myeloid compartment such as CGD.

Short-term hematopoietic reconstituting cells have been identified in mice, nonhuman primates, and among human cells that engraft xenogeneic hosts. We now present clonal marking data demonstrating a rapid but unsustained contribution of cultured human autografts to the initial phase of hematologic recovery in myeloablated patients. Three patients received transplants of granulocyte colony-stimulating factor–mobilized autologous peripheral blood (PB) cells, of which a portion (8%-25% of the CD34+ cells) had been incubated in vitro with growth factors (5 days) and clinical grade LN retrovirus (3-5 days). More than 9% of the clonogenic and long-term culture-initiating cells harvested were transduced. Semiquantitative and linear amplification-mediated polymerase chain reaction analyses of serial PB samples showed that marked white blood cells appeared in all 3 patients within 11 days and transiently constituted up to 0.1% to 1% of those produced in the first month. However, within another 2 to 9 months, marked cells had permanently decreased to very low levels. Analysis of more than 50 vector insertion sites showed none of the clones detected in the first month were active later. Eighty percent of inserts were located within or near genes, 2 near CXCR4. These findings provide direct evidence of cells with rapid but transient repopulating activity in patients and demonstrate their efficient transduction in vitro.

Background Numerous studies suggest an increased vascular risk in patients with migraine, in particular in those with aura. A possible link between both conditions might be a dysfunction of the vascular endothelium. This observational study analyzed the endothelial markers angiopoietin-1, angiopoietin-2, Tie-2, sFlt-1 and NT-proBNP for the first time in migraineurs, patients with other primary headache disorders and healthy controls. Methods Patients with episodic migraine with and without aura, episodic cluster headache, tension-type headache and healthy controls were included. Blood samples were obtained during migraine attacks and headache-free periods in migraineurs, in and out of bout in cluster headache and during headache-free periods in tension-type headache and healthy individuals to analyze markers of endothelial function. Results No significant difference in endothelial markers between migraine, other headache disorders and healthy controls was detected. There was no significant difference between migraine attacks and headache-free intervals. Additionally, no distinction could be found between migraine with and without aura. Discussion The endothelial markers analyzed do not display a characteristic pattern in different headache disorders especially migraine compared to healthy controls. The novel findings of our study indicate that factors other than endothelial dysfunction seem to be responsible for the at least statistical association of migraine with vascular disease.

Background: Atrial natriuretic peptide (ANP) is a well-known prognostic marker of outcome and mortality in patients with cardiovascular disease. Midregional proatrial natriuretic peptide (MR-proANP) is a stable fragment of the ANP precursor hormone. As a prognostic marker after ischemic stroke, it reliably predicts poststroke mortality and functional outcome. This study aimed to analyze the prognostic value of MR-proANP in patients with hemorrhagic stroke, i.e. subarachnoid (SAH) and intracerebral hemorrhage (ICH). Methods: MR-proANP was analyzed in patients with spontaneous SAH or spontaneous ICH. All patients were prospectively randomized into two treatment arms: (1) a prophylactic normothermia group with a target core temperature 36.5°C using endovascular cooling, and (2) a control group with conventional stepwise predefined fever management using antipyretic medication and surface cooling. Blood samples were obtained on admission and on days 4 and 7. Measurement of MR-proANP was performed in serum using sandwich immunoassay. The primary endpoint was functional outcome [assessed by the Glasgow Outcome Score (GOS)] and the secondary endpoints were mortality within 180 days after hemorrhagic stroke and influence of temperature on MR-proANP. A favorable outcome was defined as GOS 4-5, and the patients were considered to have a poor outcome with a 180-day GOS score between 1 and 3. Results: Analysis of MR-proANP was performed in 24 patients with spontaneous SAH and 22 patients with spontaneous ICH. MR-proANP was elevated on days 4 and 7 as compared to baseline levels (p < 0.05 and p < 0.001, respectively). High MR-proANP levels (>120 pmol/l) were associated with increased mortality and poor outcome (after 180 days; p < 0.05, respectively). There was no significant difference regarding MR-proANP serum concentrations between the endovascular and the control groups. Conclusions: Increased levels of MR-proANP are independently associated with poor functional outcome and increased mortality after 180 days in patients with hemorrhagic stroke. Endovascular temperature control had no significant influence on MR-proANP levels.

Background Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are involved in vascular remodeling, (neuro)inflammation, blood-brain barrier breakdown and neuronal apoptosis. Proinflammatory mechanisms are suggested to play an important role during early brain injury and cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). This study aimed to analyze MMP-3, MMP-9, TIMP-1 and TIMP-3 in patients with SAH and their respective association with cerebral vasospasm (CVS). Methods Blood samples were collected in 20 SAH patients on days 1 to 7, 9, 11, 13 and 15 and 20 healthy age and gender matched volunteers. Serum MMPs and TIMPs were analyzed using enzyme-linked immunosorbent assay. Doppler sonographic CVS was defined as a mean blood flow velocity above 120 cm/sec in the middle cerebral artery. When discharged from hospital and at 6 month follow-up neurological outcome was evaluated using the Glasgow Outcome Score and the modified Rankin Scale. Results MMP-9 was higher in SAH patients compared to healthy controls (p

Fever is a very frequent complication of intensive care treatment and an independent predictor of unfavourable outcome and mortality in most patients with an acute severe neurologic injury. Today not only treatment but even more prevention of fever has become the focus of intensivists. Preliminary animal data for the beneficial neuroprotective effect of therapeutic hypothermia could not satisfyingly be reproduced in patients raising questions about the possible side effects of hypothermia. Controlled prophylactic normothermia (36.5°C) prevents secondary injury through consequent treatment of fever and limits dose-dependent side effects through therapeutic hypothermia. Novel endovascular and gel-pad surface cooling measures have shown to be feasible and efficacious in inducing and maintaining even long-term controlled normothermia.

For almost a century, therapeutic hypothermia - or as it was termed in the early days: hibernation - has been discussed as a potential neuroprotective measure, in particular in patients suffering from severe intracranial disease leading to impairment of consciousness, associated with fever [1-3]. In a wide range of diseases, secondary damage to the brain or other organs follows the initial impact and may be responsible for aggravation of disease condition or clinical state, in particular neurological morbidity and/or mortality [4-11]. Therapeutic hypothermia, recently renamed targeted temperature management, including prophylactic normothermia, has been used to improve this secondary impact onto brain and other organ tissue. This holds true, in particular, for neurological and neurosurgical intensive care patients since secondary brain and nervous tissue injury may preclude a potentially benign course of disease. The mechanisms of action of hypothermia are complex, not yet fully understood. Therapeutic hypothermia/targeted temperature management aims to attenuate a cascade of secondary injury mechanisms, which is started immediately after the initial event (primary injury) and may last for hours and even days [4,6,12]. The majority of research has focused, so far, on these secondary injury processes being destructive to brain and nervous tissue. It may be expected that any such protective effect can be replicated in other organs and tissues during therapeutic hypothermia/targeted temperature management. A wide range of side effects may negate and counteract its positive initial effect; this implies side effects of hypothermia per se and side effects of rewarming or inconstant maintenance of temperature levels [13-17]. This abstract limits itself to potential pathophysiological mechanisms of actions, the risks of any such mechanism and side effects derived from them [4,5,10,12,16-18]. The protective effect of hypothermia may be explained by several pathways. A decreased metabolism with less oxygen and energy consumption and carbon dioxide production may prevent secondary injury when oxygen supply is interrupted or, at least, impaired. However, it needs to be stressed that the reduction in metabolic rate, as seen in hypothermia, requires adjustment in ventilator setup, insulin infusion rate, correct interpretation of electrolytes, in particular low phosphate, magnesium and potassium levels. Of particular interest are the rebound phenomena during rewarming or when, involuntarily, the temperature cannot be maintained at the targeted low level. Following ischemia, hypoxia or direct trauma apoptotic processes may be initiated in brain tissue and neuronal cells may even become necrotic. In these earliest stages these pathways may be blocked by hypothermia. However, little is known about the time frame and best window of opportunity to use therapeutic hypothermia to prevent initiation of apoptotic/necrotic processes. Any type of neuronal injury may provoke the neuro-excitatory cascade, starting off with excessive calcium influx, glutamate receptor activation, neuronal hyperexcitability, eventually leading to cell death even after reperfusion and normalization of glutamate levels. It has been suggested that therapeutic hypothermia may reduce cellular/neuronal damage following this neuro-excitatory cascade. It has been accepted that the release of free radicals may be deleterious to both neuronal cells and the brain's defense mechanisms alike. Whether the direct impact or the ischemia reperfusion injury is overwhelmingly responsible for the release/increase of free radicals oxidizing and damaging neuronal cell components is both still a matter of discussion and of limited interest when therapeutic hypothermia comes into play. Hyperexcitability, cellular hyperactivity, mitochondrial dysfunction, ion-pump failure and reduction in cellular membrane integrity may lead to intracellular and, consequently, also intercellular/extracellular acidosis. Early initiation of hypothermia may improve this full spectrum of cellular failure, improve brain glucose and energy metabolism and reduce lactate accumulation; with this, intracellular and intercellular acidosis will improve and eventually metabolic recovery be enhanced [4,19-21]. Any type of brain injury is capable of disrupting the blood brain barrier leading to enhanced vascular permeability, brain edema, vascular permeability and perivascular hemorrhage. Brain edema, both after ischemia/hypoxia and traumatic injury peaks after 24 to 72 hours (sometimes reaching its highest peak even after this period of time) - thus opening widely the therapeutic window - allowing for therapeutic hypothermia to reduce brain edema via stabilizing the disrupted blood-brain barrier and vascular permeability. After brain injury proinflammatory mediators are released, leucocytes cross the - already impaired - blood-brain barrier leading to an accumulation of inflammatory cells in the brain. This inflammatory response starts within 1 hour after injury and may persist for up to 5 days, a fact which also suggests a widely open therapeutic window for intervention. Hypothermia has been shown to reduce ischemia induced inflammatory and immune reactions [4,19-22]. In healthy persons, brain temperature is around 0.5 to 1°C higher than core body temperature. In any type of brain injury, in particular, in patients with fever or hyperpyrexia respectively, injured areas may be definitely hotter (up to 2°C post injury), most probably due to transitory cellular hyperactivity. Local brain edema might lead to cerebral thermopooling adding to hyperthermia-related neuronal cellular injury [4,16,18-21]. Cooling below 35°C has been shown to affect coagulation, it depends on the initial type of brain injury whether a procoagulatory effect or an anticoagulatory effect is believed to be neuroprotective in an individual case. Targeted temperature management may influence the secretion of vasoconstricting substances (for example, endothelin) or vasodilating substances (for example, prostaglandins). Their balance is essential to maintain homeostasis. Ischemic or traumatic conditions may increase vasoconstricting substances thus leading to reduced cerebral blood flow. Whether hypothermia is capable of regulating/improving cerebral perfusion is still a matter of investigation, pending the influence of cerebral autoregulation and the quantity of secreted vasoactive mediators in brain-injured patients with cerebral ischemia or any other type of injury [10]. Whether epileptic activity, in particular, subtle nonconvulsive status epilepticus, accepted to indicate severe brain damage, can be positively influenced by therapeutic hypothermia still needs further research. However, it is accepted that a subtle nonconvulsive status epilepticus occurring in the acute phase of brain injury is - per se - adding to neuronal destruction [10,16]. While many pathophysiological processes and cascades may be influenced by targeted temperature management/therapeutic hypothermia and/or even prevention of fever through prophylactic normothermia, it is unclear whether in all types of severely brain-injured patients (for whatever reason) the benefits of this therapeutic hypothermia always outweigh its risks. It is now fully accepted and of a high level of evidenced medicine that in cerebral hypoxia (in a patient with cardiac arrest due to a shockable arrhythmia) as well as asphyxial encephalopathy a 24-hour therapeutic hypothermia (33 to 34°C), irrespective of the type of cooling, improves neurological outcome; that is, morbidity but also mortality [7,10]. Whether therapeutic hypothermia/targeted temperature management or prophylactic normothermia may improve outcome in other diseases, as discussed in this meeting, is still not clear. It needs to be stressed that even such seemingly similar diseases as global hypoxia (in cardiac arrest due to a shockable arrhythmia), asphyxial encephalopathy and ischemic stroke have so few pathophysiologic cascades in common. Therefore, they may not be treated all alike, in particular, with respect to type, duration, speed and depth of hypothermia as well as rewarming management [23]. It has already been demonstrated that in hypoxic encephalopathy hypothermia for 24 hours may be sufficient. However, disease entities such as ischemic stroke, hemorrhagic stroke with formation of peri-hematomal edema, traumatic brain injuries with prolonged secondary insult or the wide range of neuronal injuries after subarachnoid hemorrhage may present even more complex pathophysiologic mechanisms. Moreover, different pathologies such as encephalitis and bacterial meningitis or even spinal cord injury may all require a targeted and personalized approach to this adjunctive therapy. In some cases, prolonged hypothermia may be equally necessary as in other cases mild hypothermia or even only prophylactic normothermia may suffice. It may be stated beyond doubt that the neuroprotective effect of moderate hypothermia (33 to 34°C) has been shown in cerebral hypoxia and asphyxial encephalopathy. However, different neurocritical care disease entities as discussed above have different mechanisms of primary insults as well as the mechanisms and cascades of secondary brain injury and therefore require a different therapeutic approach in respect of temperature management. Any type of therapeutic measure, still being the subject of research, must never harm the patient. Hypothermia-induced neurological signs and symptoms must never be misinterpreted and as a matter of course the diagnosis of brain death can never be confirmed under hypothermic conditions [24].

It is a pleasure to announce the 2nd Innsbruck Hypothermia Symposium. We are very happy that Critical Care has agreed to publish extended abstracts submitted by invited renowned scientists from all over the world; that is, Europe, the Americas, Asia. Neuroprotection - potentially achieved by targeted temperature management (that is, therapeutic hypothermia or prophylactic controlled normothermia) - is essential in emergency and acute care management of various severe neurologic and cardiologic diseases. Beyond neuroprotection - for this aim, therapeutic hypothermia has been established after resuscitation of patients with cardiac arrest due to a shockable arrhythmia and in neonatal asphyxic encephalopathy - therapeutic hypothermia and prophylactic controlled normothermia have been published in single case reports, retrospective, open, but also in prospective randomised controlled trials in many other emergency disciplines in which both neuroprotection and protection of other organs and tissues are the target of our therapeutic endeavours. The Medical University Innsbruck, Austria, is happy to organise this conference on temperature management, therapeutic hypothermia and prophylactic normothermia respectively, to be held in Portoroz, Slovenia. In accordance with the first Meeting on Hypothermia, which was held in Miami, Florida, USA (CHilling At the Beach), we are proud to suggest the acronym CHAB standing for take Care for Heart And Brain, characterising the major target organs of therapeutic and, possibly also, prophylactic temperature management. Again, we have been able to gather most renowned scientists, neurointensivists and intensivists, emergency physicians, cardiologists and other specialists to cover the entire scientific and clinical spectrum of emergency temperature management, technical aspects of cooling and management of potential complications including shivering, but also temperature management in neurology, neurosurgery, intensive care medicine, in the operation theatre, cardiology, infectious diseases, and so forth. Beyond that we cross borders and discuss hypothermia and intracranial pressure, pharmacodynamics in hypothermic patients and the influence of hypothermia onto pharmacokinetics/pharmacodynamics, hypothermia in refractory status epilepticus or heat stroke, hypothermia and advanced neuromonitoring, hypothermia and nutrition, shivering and the critical issue of rewarming, amongst other topics. The aim of this symposium is to enhance the knowledge on temperature management, increase the readiness and stimulate the preparedness to institute therapeutic hypothermia and/or prophylactic controlled normothermia, respectively, in patients in need of tissue and organ protection, uncontrolled body temperatures possibly adding - per se - to neuronal damage. Knowing the medical literature and knowing the issue of potentially life-threatening side effects and complications incurred by this invasive therapeutic manoeuvre, it is the foremost aim of this symposium and this supplementary issue of Critical Care to discuss all these aspects of targeted temperature management in emergency, critical care and, in particular, neurocritical patients and conditions. For this reason the organisers have agreed that the discussion of these various issues, being so important for general critical care, neurocritical care and emergency medicine, must be distributed as widely as possible, making it available to critical care and neurocritical care specialists all over the world. Therefore we are extremely grateful to the Editors of Critical Care for providing a forum for all of the extended abstracts of all invited speakers, covering the entire field of adult emergency and critical care medicine. We do hope and we are convinced that this supplementary issue will be a source of inspiration and knowledge, hopefully becoming a work of reference for intensivists, neurologists, neurointensivists, cardiologists and all emergency physicians alike. It is the aim of the organisers to establish a series of such symposia within the next years in order to keep up with all the developments in this field and to maintain the highest possible level of knowledge of targeted temperature management in the community of emergency and intensive care physicians.

Therapeutic hypothermia (TH) has been recently accepted as a powerful medical intervention for providing neuroprotection to patients sustaining cardiac arrest and hypoxic-ischemic encephalopathy. Further, TH has also been explored as a potential treatment strategy for patients with traumatic brain injury and ischemic or hemorrhagic stroke (for review see [1]). With the widespread propagation of TH as treatment for intracranial hypertension in patients who are refractory to standard interventions [2], induction and maintenance of TH is no longer restricted to the early period (that is, the first 12 to 24 hours) of acute brain injuries but has expanded over several days until rewarming [3]. Therefore, it is evident that, in addition to the disease process itself, TH has a major impact on ICU management such as analgesia and sedation, ventilator therapy, cardiocirculatory support, or artificial nutrition. Importantly, the significance of nutrition therapy in critically ill patients cannot be overstated [4]. Critical illness typically induces a catabolic stress state proportional to the severity of injury, predisposing patients to serious nutritional deficits coupled with multiple organ dysfunction, delayed recovery and disproportionate mortality [5]. Effective nutrition therapy can play a major role in attenuating the catabolic response and avoiding the harmful effects of prolonged hypermetabolism. International guidelines provide recommendations for timing until initiation of artificial nutrition, administration route, energy targets and type of nutrients in critically ill patients [4,6]. Starting early nutrition within 24 to 48 hours, primarily using the enteral route, is a proactive strategy to reduce energy deficit [7]. Importantly, underfeeding and overfeeding must be avoided, which implies monitoring nutritional delivery to timely identify an increasing energy gap or excess administration [8]. Energy requirements are most accurately assessed by measuring resting energy expenditure using indirect calorimetry; however, this method is not widely available [9]. Instead, guideline targets could be applied, with a cautious initial energy requirement of 20 to 25 kcal/kg/day increasing thereafter in the recovery phase. Enteral nutrition has the advantage of preventing adverse structural and functional alterations of the gut barrier and of improving mesenteric blood flow as well as enhancing local and systemic immune responsiveness [10]. On the other hand, critically ill patients may often have intolerance to gastric feeding [11]. Prokinetic medications may help restore gastric emptying and promote gastrointestinal motility [12]. Persistent intolerance to enteral nutrition selects patients who will require supplemental parenteral nutrition [6]. Another issue in the context of metabolic consequences of nutrition therapy that deserves attention is glycemic control. Both hyperglycemia and hypoglycemia are of particular concern in critically ill patients [13]. However, to date the goal for blood glucose level and whether intensive or a moderate insulin therapy should be employed in these patients, especially with acute brain injuries, is still uncertain [14]. Implementation of a protocol to promote control of serum glucose when providing nutrition therapy is advocated, and a range of 110 to 150 mg/dl (6.1 to 8.3 mmol/l) may be most appropriate [4]. Whether the aforementioned recommendations on artificial nutrition of the general intensive care patient population can also be applied on equal terms to patients undergoing TH is still a matter of debate. Studies addressing the various issues of nutrition therapy in TH are scarce, as evidenced by a contemporary PubMed search including bibliographies of published reviews. So far, data are available on the course of energy expenditure in patients treated with TH suffering from ischemic or hemorrhagic stroke [15,16] and severe traumatic brain injury [2]. In sedated, ventilated patients receiving muscle relaxants a significant decrease in resting energy expenditure ranging at approximately 75 to 85% of baseline values during TH could be demonstrated. Downregulation of cerebral and overall metabolism as well as muscle relaxation has been discussed as major factors of the reduction in energy expenditure [15]. In contrast, shivering, an anticipated consequence and potentially major adverse effect of TH, has been shown to be strongly associated with graded increases in systemic metabolism [16]. This clearly indicates the need for an individualized determination of the optimal amount of energy to be delivered during TH. Further, one has to bear in mind that other (patho)physiological changes might occur in patients treated with TH. During the maintenance period of TH, electrolyte replacement is often needed because of a decrease in serum levels of potassium, magnesium and phosphate. With rewarming, these electrolytes are released from intracellular stores and move to extracellular spaces. Therefore, care must be taken to avoid rebound hyperkalemia [17]. In addition, insulin resistance, which can lead to hyperglycemia, may occur during TH. Again, in the rewarming period insulin sensitivity may increase rapidly, resulting in sometimes marked hypoglycemia if the insulin dose is not adjusted appropriately [17]. In conclusion, many questions regarding the nutrition therapy of patients treated with TH remain to be answered. Further studies that focus on the optimal amount of caloric intake, timing, preferred route of administration and monitoring of nutrition delivery during targeted temperature management are urgently needed.

Background Angiopoietin-1 (Ang-1) and -2 (Ang-2) are keyplayers in the regulation of endothelial homeostasis and vascular proliferation. Angiopoietins may play an important role in the pathophysiology of cerebral vasospasm (CVS). Ang-1 and Ang-2 have not been investigated in this regard so far. Methods 20 patients with subarachnoid hemorrhage (SAH) and 20 healthy controls (HC) were included in this prospective study. Blood samples were collected from days 1 to 7 and every other day thereafter. Ang-1 and Ang-2 were measured in serum samples using commercially available enzyme-linked immunosorbent assay. Transcranial Doppler sonography was performed to monitor the occurrence of cerebral vasospasm. Results SAH patients showed a significant drop of Ang-1 levels on day 2 and 3 post SAH compared to baseline and HC. Patients, who developed Doppler sonographic CVS, showed significantly lower levels of Ang-1 with a sustained decrease in contrast to patients without Doppler sonographic CVS, whose Ang-1 levels recovered in the later course of the disease. In patients developing cerebral ischemia attributable to vasospasm significantly lower Ang-1 levels have already been observed on the day of admission. Differences of Ang-2 between SAH patients and HC or patients with and without Doppler sonographic CVS were not statistically significant. Conclusions Ang-1, but not Ang-2, is significantly altered in patients suffering from SAH and especially in those experiencing CVS and cerebral ischemia. The loss of vascular integrity, regulated by Ang-1, might be in part responsible for the development of cerebral vasospasm and subsequent cerebral ischemia.

To evaluate the pathophysiologic changes in the inner ear during the course of severe cerebral malaria in an established animal model, C57 BL/6J mice.This study aims to examine the hearing threshold, the histological changes and ICAM-1 expression in the murine cochlea.Four of seven mice showed an expected hearing loss of 20 dB or more. The light microscopy of the inner ear did not show any morphologic alterations. The immunohistochemical analysis for ICAM-1 showed intensive staining in the stria vascularis of sick animals and hardly any reaction in healthy controls.The up-regulation of ICAM-1 in the stria vascularis - generating the endocochlear potential - suggests its involvement in plasmodial infection.

BACKGROUND: As brain temperature is reported to be extensively higher than core body temperature in traumatic brain injury (TBI) patients, posttraumatic hyperthermia is of particular relevance in the injured brain. OBJECTIVE: To study the influence of prophylactic normothermia on brain temperature and the temperature gradient between brain and core body in patients with severe TBI using an intravascular cooling system and to assess the relationship between brain temperature and intracranial pressure (ICP) under endovascular temperature control. METHODS: Prospective case series study conducted in the neurologic intensive care unit of a tertiary care university hospital. Seven patients with severeTBI with a Glasgow Coma Scale score of 8 or less were consecutively enrolled. Prophylactic normothermia, defined as a target temperature of 36.5� C, was maintained using an intravascular cooling system. Simultaneous measurements of brain and urinary bladder temperature and ICP were taken over a 72-hour period. RESULTS: The mean bladder temperature in normothermic patients was 36.3 6 0.4� C, and the mean brain temperature was determined as 36.4 6 0.5� C. The mean temperature difference between brain and bladder was 0.1� C. We found a significant direct correlation between brain and bladder temperature (r = 0.95). In 52.4% of all measurements, brain temperature was higher than core body temperature. The mean ICP was 18 6 8 mm Hg. CONCLUSION: Intravascular temperature management stabilizes both brain and body core temperature; prophylactic normothermia reduces the otherwise extreme increase of intracerebral temperature in patients with severe TBI. The intravascular cooling management proved to be an efficacious and feasible method to control brain temperature and to avoid hyperthermia in the injured brain. We could not find a statistically significant correlation between brain temperature and ICP.

Background Plasmodium falciparum malaria has been suspected to cause hearing loss. Developmental, cognitive and language disorders have been observed in children, surviving cerebral malaria. This prospective study aims to evaluate whether malaria influences hearing in mice. Methods Twenty mice were included in a standardized murine cerebral malaria model. Auditory evoked brainstem responses were assessed before infection and at the peak of the illness. Results A significant hearing impairment could be demonstrated in mice with malaria, especially the cerebral form. The control group did not show any alterations. No therapy was used. Conclusion This suggests that malaria itself leads to a hearing impairment in mice.

Background and Purpose— We sought to study the effectiveness and safety of endovascular cooling to maintain prophylactic normothermia in comparison with standardized, stepwise, escalating fever management to reduce fever burden in patients with severe cerebrovascular disease. Methods— This study was a prospective, randomized, controlled trial with a blinded neurologic outcome evaluation comparison between prophylactic, catheter-based normothermia (CoolGard; ie, body core temperature 36.5°C) and conventional, stepwise fever management with anti-inflammatory drugs and surface cooling. Patients admitted to 1 of the 2 neurointensive care units were eligible for study inclusion when they had a (1) spontaneous subarachnoid hemorrhage with Hunt & Hess grade between 3 and 5, (2) spontaneous intracerebral hemorrhage with a Glasgow Coma Scale score ≤10, or (3) complicated cerebral infarction requiring intensive care unit treatment with a National Institutes of Health Stroke Scale score ≥15. Results— A total of 102 patients (56 female) were enrolled during a 3.5-year period. Fifty percent had a spontaneous subarachnoid hemorrhage, 40% had a spontaneous intracerebral hemorrhage, and 10% had a complicated cerebral infarction. Overall median total fever burden during the course of treatment was 0.0°C hour and 4.3°C hours in the catheter and conventional groups, respectively ( P Conclusions— Long-term, catheter-based, prophylactic normothermia significantly reduces fever burden in neurointensive care unit patients with severe cerebrovascular disease and is not associated with increased major adverse events.

Clinical use of purified hematopoietic stem cells in myeloablated patients requires cotransplantation of short-term repopulating cells (STRCs) to ensure timely count recovery. Here, we investigated the flow fluorescence-based side population (SP) phenotype of mobilized human peripheral blood (mPB) cells that rapidly repopulate the highly permissive nonobese diabetic/severe combined immunodeficient (NOD/SCID)-beta2 microglobulin(-)/- mouse. No SP cells from this source regenerated detectable progeny in these mice before 8 weeks, although by 12 weeks human B-lymphoid cells were seen in some recipients of SP mPB cells. All myeloid reconstituting activity, including that seen within 3 weeks after transplantation, was associated with the non-SP fraction. Isolation of SP cells depletes human mPB of the rapid myeloid reconstitution capacity provided by myeloid-restricted STRCs which are vital for early hematologic recovery in clinical transplant recipients.

Objective Human mobilized peripheral blood (mPB) is known to contain high numbers of cells with rapid but short-term repopulating activity in NOD/SCID-β2microglobulin −/− mice. Here we assessed the effect of short-term culture on these cells and compared the levels of retained activity with the pace of hematologic recovery in myeloablated patients transplanted with similarly cultured autografts of the same cells. Patients and methods In a phase 1 clinical study, mPB cells were collected from 6 advanced cancer patients. CD34 + cells were then harvested, cultured for 3 days in the presence of early-acting growth factors, and transplanted, and posttransplant recovery of blood cell parameters monitored. Assays for primitive hematopoietic activity using both in vivo (in NOD/SCID-β2microglobulin −/− mice) and in vitro (CFC and LTC-IC) endpoints were also performed on the cells pre- and posttransplant. Results All patients showed event-free, timely leukocyte recoveries but slightly delayed platelet recoveries in some cases. During the 3-day period of culture, the CFCs doubled but the LTC-IC activity decreased (twofold), as did the short-term repopulating activity in NOD/SCID-β2microglobulin −/− mice. Conclusion Patients can be transplanted with 3-day cultured autografts with minimal effects on hematologic recovery. This is associated with a variable but, on average, modest loss of short-term repopulating activity detectable in NOD/SCID-β2microglobulin −/− mice.

Standard operating procedures both for scientific study protocols as well as in routine daily practice stress the importance of slow rewarming after targeted temperature management/moderate therapeutic hypothermia (32 to 34°C) [1-3]. The recommended rewarming speed ranges from 0.1 to 0.4°C/hour, the former allowing a minimum of 24 hours to reach normothermia levels whereas in case of the latter the normothermic temperature levels are reached within 6 to 8 hours. It has been well known and it is widely accepted that abrupt temperature changes, with insufficient temperature control methods, cause change in energy expenditure and intracranial pressure and a negative effect onto the cerebral perfusion pressure and cerebral blood flow. In avalanche survivors the so-called afterdrop has been described to be an additional potentially dangerous condition [4,5]; hypercapnia has been shown to increase the core temperature cooling rate in snow burial victims; furthermore, shivering influences both cooling and rewarming and the cooling afterdrop [4,5]. In the rat model the speed of rewarming plays a crucial role in the development of acute lung injury in intestinal ischemia treated with therapeutic hypothermia. Reactive oxygen species have been shown to play an important role in the pathogenesis of various injuries, including brain injury and lung injury [6]. Besides this, inflammatory reaction and nitric oxide levels are clearly influenced both by therapeutic hypothermia and speed of rewarming. It might be surmised that more gradual rewarming and the addition of anti-inflammatory drugs during this period of rewarming [7,8] might add to or even enhance the neuroprotective effect of therapeutic hypothermia/targeted temperature management [9,10]. This assumption is underlined by the findings that biogenic amines that have been demonstrated to protect cells from apoptotic cell death (for example, serotonin and dopamine) protect cells against rewarming-induced active oxygen species formation and apoptosis [11]. Thus, it is correctly hypothesized that adding drugs containing these biogenic amines or releasing endogenously serotonin and dopamine might help to prevent potential negative side effects of rewarming [11]. Most of the knowledge of post-hypothermic rewarming effects has been gained in experimental settings [1,12,13]. More than 10 years ago the neuroprotective effect visualized by amyloid precursor protein positive axonal swellings, quantifying them per unit area and, thus, serving as marker of both pathophysiologic and neuroprotective effect respectively, has been shown to be reversed completely when normothermia was achieved very rapidly within 20 minutes [3,14]. The originally documented axonal protection was not only eliminated by this rapid rewarming but, in fact, the overall burden of axonal damage was dramatically increased, reaching a virtual doubling of the numbers of damaged axons seen per unit area [3]. Not only amyloid precursor protein accumulation but also neurofilament compaction was seen to be exacerbated by rapid rewarming [3]. Besides this and other neuropathological effects there is now clear evidence that cerebral microcirculation, both in traumatic brain injury and in other severe intracranial diseases, is structurally and functionally perturbed and that this perturbation can be attenuated by hypothermia followed by slow rewarming [2,15]. Similar to the situation with axonal injury, discussed above, the hypothermic protection against cerebral microcirculation impairment can be reversed or the injury even exacerbated by rapid post-hypothermic rewarming [2]. In addition, compelling evidence has been found that traumatically induced or hypoxia-induced generation of oxygen radicals significantly contributes to secondary insult onto brain cells but also damaging endothelium and smooth muscle cells [13]. When employing hypothermic intervention followed by slow rewarming, significant vascular protection was provided; in particular, the generation of oxygen radicals was reduced [14]. The protective effect of hypothermia, once again, is not only a function of time of initiating target temperature and overall duration of hypothermia. Even more importantly, all these positive effects are reversed by rapid rewarming enhancing vascular dysfunction following neuronal injury [10]. Povlishock and Wei clearly state that in the context of traumatically induced axonal damage, microvascular dysfunction, and cerebral contusion, any potentially beneficial effect of hypothermic intervention is consistently reversed and the lesion even exacerbated when post-traumatic hypothermia is followed by rapid rewarming [2]. Most likely, both direct and indirect mitochondrial perturbation together with processes mediated by free radicals influence the ensuing biology and pathophysiology. Post-hypothermic rewarming rates and the potential adverse consequences of rapid rewarming are closely observed in the field of transplantation medicine wherein hypothermic organ maintenance and rewarming are integral to successful organ viability and subsequent transplantation. Rapid rewarming is highly damaging in case of liver transplantation, most likely due to rapid ATP depletion, energy failure and oxygen radical production associated with hepatic mitochondrial damage. Extrapolation from this body of experimental and human medical knowledge clearly indicates/allows the statement that any type of targeted temperature management/therapeutic hypothermia needs to be followed both by very slow rewarming on the one hand and maintenance of normothermia after reaching the normothermia level on the other hand [16-19]. Exactly this aspect of slow/very slow rewarming has been partially neglected in most recently published studies [19,20]; in particular, on therapeutic hypothermia in traumatic brain injury [21]. In view of the ongoing pathophysiologic processes leading to secondary neuronal damage over a period of more than 5 days post trauma, not only that the duration of therapeutic hypothermia but also the speed of rewarming (0.4°C/hour) need to be questioned and might be interpreted as the major cause of the negative study outcome. Every researcher, when compiling a study protocol, as well as every clinician is strongly advised to accept the impact of duration of hypothermia and speed/rate of rewarming as being crucial elements both in research and clinical practice. Although it might correctly be surmised that the duration of therapeutic hypothermia is associated with the incidence and intensity of complications, the same might hold true for too short a duration and too quick a rewarming rate. Further studies are needed to evaluate various durations (1 day vs. 3 or 5 days, vs. even longer) both in traumatic brain injury but also in other neurologic diseases that trigger off secondary pathophysiological processes such as ischemic stroke (concept of penumbra), spontaneous intracerebral hemorrhage (peri-hematoma edema), traumatic brain injury or spontaneous aneurysmatic subarachnoid hemorrhage with pathophysiologic processes going on for days and even weeks after the acute ictus. In view of these considerations, prolonging therapeutic hypothermia and, in particular, slowing the rate of rewarming might be the crucial clue to achieve the best possible benefit from targeted temperature management/moderate therapeutic hypothermia without counteracting these benefits by too speedy a rewarming rate. In addition, maintaining normothermia after hypothermia and rewarming seems to be essential in order to avoid the negative rebound effects [22,23]. Finally, it needs again to be noted that a too rapid rewarming might lead to vasodilatation, thus aggravating intracranial pressure, reducing cerebral perfusion pressure and leading to a negative effect on overall neurological outcome [1,19].

Brian Kellock quotes in his book The Fibreman the seven-year-old (that is, in the year 1918) Denis Burkitt discussing respectfully his uncle Dr Roland Burkitt's legendary reputation amongst his patients in Kenya, Africa, as: '... he believed in curing fevers, in particular in delirious patients, by artificially lowering the patients' temperature ...' [1]. Obviously, Dr Roland Burkitt, the uncle of the legendary Prof. Dr Denis Burkitt, after whom the African lymphoma and its association with Epstein-Barr virus was named, had realized that lowering the body temperature in patients with high fevers, in Kenya highly likely to being due to cerebral malaria, meningitis or encephalitis, might influence positively the course of such potentially - at this time, in many instances, definitely - life-threatening disease [1]. Zdravev stipulated that otogenous brain abscesses not only need to be surgically evacuated but, when causing cerebral herniation, may benefit from lowering body temperature. He was the first to conclude that high body temperature in patients with increased intracranial pressure may be a deleterious association [2]. The wide variety of mechanisms of injury that are exaggerated by hyperthermia and may be ameliorated by moderate hypothermia are described elsewhere in this supplement (see abstract A1). They include mechanisms of neuroexcitotoxicity [3], release of free radicals, changes in blood-brain barrier and vascular permeability, the release of proinflammatory mediators, drawing leucocytes across the blood-brain barrier, increasing the number of inflammatory cells in the brain tissue and the passage of neutrophils, phagocytes, monocytes and macrophages into the brain, additionally injuring neuronal cells by stimulating further immune reactions [4]. Whether interfering with these mechanisms by moderate hypothermia may reduce secondary insult onto neuronal cells and brain tissue is still a matter of discussion. What has been known for long time is that increased intracranial pressure, as frequently seen in viral encephalitis, severe bacterial meningitis and/or brain abscesses, may be modified by therapeutic hypothermia/targeted temperature management [5]. In addition, long-term morbidity and mortality in CNS infection may additionally deteriorate if bacterial meningitis is complicated by cerebral infarction, occurring during the course of disease [6]. Thus, preventing cerebral infarction may be an important tool in reducing both morbidity and mortality in adults with community-acquired bacterial meningitis. Prandini and colleagues have shown that mild hypothermia reduces remarkably polymorphonuclear leucocyte infiltration in induced brain inflammation in rats compared with those without hypothermia [4]. After any type of brain injury, in particular, ischemic and ischemia reperfusion injury, the reduced brain oxygen supply quickly leads to a decrease in ATP and phosphocreatine levels, thus initiating a complex cascade of events involving excessive calcium influx into brain cells, excessive glutamate receptor activation and neuronal hyperexcitability; that is, triggering off the excitotoxic cascade [3]. Exactly this excitotoxic cascade may be responsible for provoking overt or subtle epileptic seizures in patients with CNS infection, thereby deteriorating the prognosis of these patients. Irazuzta and colleagues could nicely show that in rabbits hypothermia decreases excitatory neurotransmitter release in bacterial meningitis, in particular, the release of glutamate and aspartate, known to be involved in the pathogenesis of neuronal injury in meningitis, suggesting that hypothermia may attenuate excess neuronal stress in this disease [3]. Febrile refractory status epilepticus may be caused by presumed encephalitis carrying a very high morbidity and mortality rate [7]. In addition, it is believed that hyperthermia aggravates brain damage due to continuing epileptic activity. In a retrospective analysis Nakagawa and colleagues found a significant improvement of outcome in children with such febrile refractory status epilepticus who were treated by therapeutic hypothermia with subsequent prophylactic normothermia compared with those children with the same disease but treated only by conventional therapy without fever management [7]. The authors conclude that treatment with therapeutic hypothermia plus subsequent prophylactic normothermia may reduce neurological damage in such patients with severe acute encephalopathy due to refractory febrile convulsive status epilepticus. Another Japanese group treated an adult patient with influenza type A virus-associated encephalopathy with routine therapeutics as oseltamivir and methylprednisolone pulse therapy. Because of severe brain swelling, hypothermia was added. This combination treatment led to full recovery without neurologic sequelae [8]. A similar observation has been reported in 43 children with acute inflammatory encephalopathy and/or encephalitis, out of whom 27 were treated with mild hypothermia. These 27 children were compared with 16 similar patients who were cared for at normothermia levels [9]. The effect of therapeutic hypothermia for children with acute encephalopathy/encephalitis was observed to be dependent on the timing when cooling was initiated. Early cooling (within 12 hours of initial neurological signs of encephalopathy/encephalitis) improved outcome whereas delayed cooling (after 12 hours) tended to be even deleterious [9]. In adults, therapeutic hypothermia in CNS infection has been limited to single case reports and case series. Cuthbertson and colleagues reported induced hypothermia, together with barbiturate coma, in a meningitis patient associated with intractable raised intracranial pressure. Throughout the entire period of mild hypothermia (35°C), achieved by thiopental and external cooling, cerebral perfusion pressure was maintained above 70 mmHg. Barbiturate-induced coma and induced hypothermia were continued for 48 hours when complications (pancreatitis, ventilator-associated pneumonia) prompted one to stop these two therapy modalities. However, the patient remained without any ICP rebound, eventually being weaned from the ventilator and making a rather uneventful recovery, being discharged home with reportedly no neurologic deficits 3 weeks after the disease had began [5]. Similarly, a case with space occupying herpes simplex virus encephalitis has been reported by Wagner and colleagues. The authors correctly state that conventional intracranial pressure-lowering modalities are limited in such severe herpes simplex virus encephalitis patients and more aggressive treatment options are needed. They induced moderate hypothermia (33°C), resulting in fast and sustained control of intracranial pressure. Eventually the patient regained a relatively good functional outcome, being able to walk unassisted (GOS 4). It needs to be noted that rewarming was done very slowly (1°C/day); that is, over a period of 4 days [10]. Very recently two larger cases series have been published on the use of therapeutic hypothermia both in adult viral meningoencephalitis and in adult community-acquired meningitis by the same Croatian group

Successful gene therapy trials of ADA-SCID and SCID-X1 demonstrated the curative potential of oncoretroviral gene transfer. Integration of the retroviral vectors used in these studies has been thought to be a random process but severe side effects in gene therapy and in vitro studies revealed preferred insertion of these vectors mainly around transcription start sites. In SCID patients proliferation advantage of gene corrected cells was one reason for the success of the trials, whereas in the most recent chronic granulomatous disease (CGD) gene therapy trial corrected cells do not have any selective advantage therefore the two patients received mild busulfan treatment before transplantation. High efficiency transduction and conditioning have helped in the successful correction of the patients. Peripheral blood granulocytes show a stable expression (>10%) of the transgene (gp91phox) in patient 1 (15 months post treatment) as well as in patient 2 (11 months post treatment). We reasoned that, unlike T cells, which have the capability to proliferate independent of their bone marrow progenitors, granulocytes more directly reflect the influence of retrovirus insertion, and should therefore allow to closely monitor clonal fate in vivo and its potential relation to vector insertion. To study the clonality of the corrected myelopoiesis, the long term activity of individual cell clones, and the distribution of integration sites in active cells we carried out high sensitive LAM-PCR. The highly polyclonal composition of transduced cells forming myelopoiesis caused the sustained expression of gp91phox. Individual clones carrying the transgene could be detected at multiple time points. To define whether corrected cells have a proliferation advantage due to their vector integration we started large-scale sequencing and mapping of involved insertion sites. We here present >700 unique mappable integration sites of the two treated patients. The distribution of the SFFV based retroviral vector integration sites in this trial turned non random 5 months after transplantation. Corrected long-term myelopoiesis expanded 3- to 5- fold in the two patients due to activating common integration sites (CIS) in the zinc finger transcription factor homologs MDS1/EVI1, PRDM16, or in SETBP1, suggesting that these genes influence regulation of normal long-term hematopoiesis in humans. Our data indicate that the therapeutic benefit in this trial was activated through insertional side effects, therefore our findings have important implications in novel gene therapy approaches.

The multidrug resistance transporter, ABCG2, is expressed in primitive hematopoietic stem cells from a variety of sources. These cells are detected in dual wave-length fluorescent FACS profiles as a “side population” (SP cells) on the basis of their ability to efflux the fluorescent dye, Hoechst 33342. We have previously shown that 2 types of human short term repopulating cells (STRC) can be enumerated by limiting dilution analysis of their efficient ability to regenerate exclusively myeloid cells after 3 weeks (STRC-Ms), or both myeloid and lymphoid cells after 6–12 weeks (STRC-MLs) in NOD/SCID-b2microglobulin-/- (b2m-/-) mice. Previous findings also implicated these STRCs as determinants of the rapidity of early hematologic recovery in patients transplanted with cultured mobilized peripheral blood (mPB) cells. Here we asked whether any human STRCs have an SP phenotype and hence whether the isolation of SP cells would retain the rapid repopulating activity of a clinical transplant. CD3- SP and non-SP cells were isolated by FACS from low-density (LD) mPB cells after Hoechst staining and transplanted at limiting dilutions into 117 sublethally irradiated b2m-/- mice. The numbers and types of human hematopoietic cells present in the bone marrow of these mice were subsequently monitored by FACS analysis of bone marrow cells aspirated serially, 3, 8 and 12 wks post-transplant. A verapamil-sensitive SP population was reproducibly detected in all 5 patients’ samples studied (0.039 ± 0.012% of the CD3- LD cells). The in vivo assays failed to detect either STRC-Ms or STRC-MLs in the SP fraction and all these activities were obtained from the non-SP cells. If even a single recipient of the largest dose of SP cells transplanted had been positive, this would have detected 10% of the STRCs present. Thus, >90% of all STRC-M and STRC-ML in mPB are non-SP cells. However, 4 of 40 mice transplanted with SP mPB cells produced some B-lymphoid cells only starting 12 wks post-transplant. However, this result is difficult to interpret since subjecting the STRC-Ms to the Hoechst 33342 staining and FACS isolation procedure alone eliminated their ability to generate megakaryocytic progeny in vivo, although this did not occur when these cells were just stained for CD34 and then isolated by FACS. In addition, the differentiation behaviour of STRC-MLs was not affected by the Hoechst staining and subsequent FACS isolation procedure. In summary, we demonstrate that purification of SP cells depletes human mPB transplants of STRCs, thereby raising serious concerns about the safety of any clinical use of SP cell-enriched transplants as stem cell support after myeloablation. Our results also suggest that the staining and enrichment procedure for isolating SP human cells may differentially affect the lineage potential of some types of STRCs, including those whose activity may be indispensable for rapid and multi-lineage hematologic recovery.

Das posteriore reversible Enzephalopathiesyndrom (PRES) stellt ein akut verlaufendes Krankheitsbild dar, das durch eine unspezifische klinische Symptomatik, wie Kopfschmerzen, Sehstorung, Bewusstseinsstorung oder epileptische Anfalle, sowie charakteristische bildgebende Veranderungen im Sinne eines vasogenen Odems gekennzeichnet ist. Unterschiedliche Pathomechanismen, die zur Odembildung fuhren, werden diskutiert. Da ein PRES bei etwa 2 Drittel aller Patienten mit erhohten Blutdruckwerten assoziiert ist, wird vermutet, dass es im Rahmen einer hypertensiven Entgleisung zur Uberschreitung der oberen Autoregulationsgrenze, nachfolgender zerebraler Hyperperfusion und einem Vascular-Leak-Syndrom kommt. Daruber hinaus wird das Auftreten eines PRES auf eine endotheliale Dysfunktion mit Freisetzung von Vasokonstriktoren und Schadigung von interzellularen Adhasionsmolekulen durch endo- und exogene Noxen, wie Immunsuppressiva, Chemotherapeutika, Praeklampsie, Sepsis oder Autoimmunerkrankungen, zuruckgefuhrt. Diagnostisch wegweisend ist die Konstellation aus klinischer Symptomatik, bildgebendem Nachweis eines vasogenen Odems, das meist bilateral und parietookzipital betont lokalisiert ist, und eine uberwiegende Reversibilitat der Veranderungen. Die Therapie der Erkrankung ist symptomorientiert, eine spezifische Behandlung steht derzeit nicht zur Verfugung. Haufig fuhrt eine konsequente antihypertensive Therapie und, wenn moglich, eine Elimination der auslosenden Noxe zu einer Ruckbildung der klinischen und bildgebenden Veranderungen. Aufgrund moglicher Komplikationen, wie dem Auftreten eines Status epilepticus, zerebraler Vasokonstriktion, Ischamie oder intrazerebraler Blutung, ist bei etwa 40 % aller Patienten eine intensivmedizinische Behandlung erforderlich.

Posterior reversible encephalopathy syndrome refers to a neurological disorder characterized by headache, disorders of consciousness, visual disturbances, epileptic seizures, and subcortical vasogenic edema. About two thirds of patients develop neurological symptoms, which are associated with blood pressure fluctuations. One hypothesis is that hypertensive episodes cause autoregulatory failure, and values above the upper limit of cerebral autoregulation result in a breakthrough followed by hyperperfusion and blood-brain barrier dysfunction. In another hypothesis, endothelial dysfunction triggered by numerous factors including preeclampsia, immunosuppressive agents, chemotherapeutics, sepsis, or autoimmune disorders is thought to be the key pathomechanism. Endo- or exogenic toxic agents including pharmacological substances, cytokines, or bacterial toxins are supposed to trigger endothelial activation and dysfunction resulting in the release of vasoconstrictors, pro-inflammatory mediators, and vascular leakage. Diagnosis is usually based on clinical and neuroimaging findings that frequently show a bilateral, symmetric, and parietooccipital pattern. However, the diagnosis can often only be confirmed during the course of disease after excluding important differential diagnoses. Currently, there is no specific treatment available. Lowering of arterial blood pressure and eliminating the underlying cause usually leads to an improvement of clinical and neuroradiological findings. Admission to a critical care unit is required in about 40 % of patients due to complicating conditions including status epilepticus, cerebral vasoconstriction, ischemia, or intracerebral hemorrhage. Prognosis is favorable; in the majority of patients neurological deficits and imaging findings resolve completely.

Introduction Elevated brain potassium levels ([K+]) are associated with neuronal damage in experimental models. The role of brain extracellular [K+] in patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH) and its association with hemorrhage load, metabolic dysfunction and outcome has not been studied so far. Methods Cerebral microdialysis (CMD) samples from 28 poor grade aSAH patients were analyzed for CMD [K+] for 12 consecutive days after ictus, and time-matched to brain metabolic and hemodynamic parameters as well as corresponding plasma [K+]. Statistical analysis was performed using a generalized estimating equation with an autoregressive function to handle repeated observations of an individual patient. Results CMD [K+] did not correlate with plasma [K+] (Spearman’s ρ = 0.114, P = 0.109). Higher CMD [K+] was associated with the presence of intracerebral hematoma on admission head computed tomography, CMD lactate/pyruvate ratio >40 and CMD lactate >4 mmol/L (P