Frequency of Screening and Prevalence of Neurosyphilis in Stroke Population.

BACKGROUND AND AIMS: Syphilis and stroke are high prevalent diseases in south Brazil and estimates of concomitance and possible role of syphilis in acute stroke are lacking. Our aims are to estimate the prevalence of syphilis and neurosyphilis (NS) in a cohort of tertiary stroke center. METHODS: We reviewed all hospital records of stroke/transitory ischemic attack (TIA) using International Classification of Diseases, 10th revision, at discharge, frequency of syphilis screen, serology positivity, cerebrospinal fluid (CSF) analysis, and prevalence of NS in this stroke population applying CDC criteria. RESULTS: Between 2015 and 2016, there were 1,436 discharges for cerebrovascular events and in 78% (1,119) of these cases, some syphilis screening was performed. We have found a frequency of positive serology for syphilis of 13% (143/1,119), and higher stroke severity was the main determinant for non-screening. Applying standard NS criteria, 4.7% (53/1,119) cases with CSF analysis had NS diagnosis: 8 based on CSF-Venereal Disease Research Laboratory (VDRL) positive and 45 based on abnormal CSF white cells or protein, but CSF VDRL negative. NS VDRL positive cases were younger, had higher serum VDRL title, had more frequent HIV infection, and received NS treatment more often. Demographic and clinical characteristics were not different between NS VDRL negative and non-NS cases. CONCLUSION: Positive syphilis serology is frequent in patients with acute stroke/TIA in our region. Acute post-stroke CSF abnormalities make the diagnosis of NS difficult in the context of CSF VDRL negative.

Temporal analysis of blood-brain barrier disruption and cerebrospinal fluid matrix metalloproteinases in rhesus monkeys subjected to transient ischemic stroke.

Blood-brain barrier (BBB) disruption plays an important role in pathophysiological progress of ischemic stroke. However, our knowledge of the dynamic change of BBB permeability and its mechanism remains limited. In the current study, we used a non-human primate (NHP) MCAO model and a serial CSF sampling method that allowed us to determine the dynamic change of BBB permeability by calculating the CSF/serum albumin ratio (AR). We showed that AR increased rapidly and significantly after ischemia, and the fold increase of AR is highly correlated with the infarction size during the subacute phase. Moreover, we determined the temporal change of MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, MMP-13, TIMP-1, and TIMP-2 in CSF and serum. Each MMP and TIMP showed different change patterns when comparing their values in CSF and serum. Based on the longitudinal dataset, we showed that the fold increase of MMP-9 in serum and CSF are both correlated to infarction size. Among the measured MMPs and TIMPs, only MMP-2, MMP-13, and TIMP-2 in CSF correlated with AR to some extent. Our data suggest there is no single MMP or TIMP fully responsible for BBB breakdown, which is regulated by a much more complicated signal network and further investigations of the mechanisms are needed.

Ischemic stroke and transient ischemic attack in young adults: risk factors, diagnostic yield, neuroimaging, and thrombolysis.

BACKGROUND: Approximately 10% to 14% of ischemic strokes occur in young adults. OBJECTIVE: To investigate the yield of diagnostic tests, neuroimaging findings, and treatment of ischemic strokes in young adults. DESIGN: We retrospectively reviewed data from our Get with the Guidelines-Stroke database from 2005 through 2010. SETTING: University hospital tertiary stroke center. PATIENTS: A total of 215 consecutive inpatients aged 18 to 45 years with ischemic stroke/transient ischemic attack. The mean (SD) age was 37.5 (7) years; 51% were male. RESULTS: There were high incidence rates of hypertension (20%), diabetes mellitus (11%), dyslipidemia (38%), and smoking (34%). Relevant abnormalities were shown on cerebral angiography in 136 of 203 patients, on cardiac ultrasonography in 100 of 195, on Holter monitoring in 2 of 192; and on hypercoagulable panel in 30 of 189 patients. Multiple infarcts were observed in 31% and were more prevalent in individuals younger than age 35 years. Relevant arterial lesions were frequently detected in the middle cerebral artery (23%), internal carotid artery (13%), and vertebrobasilar arteries (13%). Cardioembolic stroke occurred in 47% (including 17% with isolated patent foramen ovale), and 11% had undetermined stroke etiology. The median National Institutes of Health Stroke Scale score was 3 (interquartile range, 0-9) and 81% had good outcome at hospital discharge. Of the 29 patients receiving thrombolysis (median National Institutes of Health Stroke Scale score, 14; interquartile range, 9-17), 55% had good outcome at hospital discharge and none developed symptomatic brain hemorrhage. CONCLUSIONS: This study shows the contemporary profile of ischemic stroke in young adults admitted to a tertiary stroke center. Stroke etiology can be determined in nearly 90% of patients with modern diagnostic tests. The causes are heterogeneous; however, young adults have a high rate of traditional vascular risk factors. Thrombolysis appears safe and short-term outcomes are favorable.

Dimethylarginine levels in cerebrospinal fluid of hyperacute ischemic stroke patients are associated with stroke severity.

We hypothesise that asymmetric and symmetric dimethylarginine (ADMA, SDMA) are released in cerebrospinal fluid (CSF) due to ischemia-induced proteolysis and that CSF dimethylarginines are related to stroke severity. ADMA and SDMA were measured in CSF of 88 patients with ischemic stroke or TIA within 24 h after stroke onset (mean 8.6 h) and in 24 controls. Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) score at admission. Outcome was evaluated by institutionalization due to stroke and the modified Rankin scale. Dimethylarginine levels were higher in patients with stroke than in TIA patients, who had higher levels than controls and correlated with the NIHSS. Logistic regression analysis confirmed that dimethylarginines were independently associated with stroke severity. The SDMA/ADMA ratio did not differ significantly between controls and stroke patients. CSF dimethylarginine levels are increased in hyperacute ischemic stroke and are associated with stroke severity.

Evaluation of lactate as a marker of metabolic stress and cause of secondary damage in acute ischemic stroke or TIA.

BACKGROUND: Accumulation of lactate in ischemic regions has been documented in acute stroke. We evaluated the relation between lactate levels in blood and cerebrospinal fluid (CSF) and ischemic stroke evolution and outcome. METHODS: Lactate was measured in blood of 187 acute ischemic stroke and TIA patients at admission, 24 h, 72 h and 7 days after stroke onset. In a subpopulation of 85 stroke patients and in 51 controls, lactate was measured in CSF. Stroke evolution was evaluated by change in the NIHSS score within the first 72 h and by occurrence of progressing stroke. At 3 months after stroke, outcome was assessed on the basis of mortality rate and the modified Rankin Scale. RESULTS: We found no relation between lactate levels in blood and stroke evolution or outcome. Lactate in CSF was higher in stroke patients than in controls and correlated with stroke evolution and outcome. Multivariate regression analyses showed that CSF lactate levels, age and stroke severity are independent predictors for stroke evolution and outcome. CONCLUSIONS: Lactate levels in CSF, but not in blood, are a reliable marker for metabolic crisis in acute ischemic stroke and correlate with the stroke evolution in the subacute phase and with long-term outcome.

Neurobrucellosis as an exceptional cause of transient ischemic attacks.

We report a series of four cases presented with transient ischemic attacks (TIA) or ischemic stroke as the predominant manifestation of neurobrucellosis (NB). Three of the patients were 20-28 years of age, and one patient was 53 years old. They all used to consume unpasteurized milk or its products. Two patients had systemic brucellosis in the past and received antibiotic treatment. Other causes of TIA including cardiac embolism, hypercoagulability, vascular malformations, systemic vasculitis, and infective endocarditis were excluded. NB was diagnosed with serological tests or cultures for Brucella in the cerebrospinal fluid. None of the patients had any further TIA after the initiation of specific treatment. NB should always be sought in young patients with TIA or ischemic stroke, especially if they have no risk factors for stroke and live in an endemic area for brucellosis, even if they do not have other systemic signs of brucellosis.

Combined proteomic approach with SELDI-TOF-MS and peptide mass fingerprinting identified the rapid increase of monomeric transthyretin in rat cerebrospinal fluid after transient focal cerebral ischemia.

Several proteins are known to be markedly expressed in the brain during cerebral ischemia, however the change in protein profiles within the cerebrospinal fluid (CSF) after an ischemic insult has not been fully elucidated. We studied the changes in the CSF proteome in rat transient middle cerebral artery occlusion model. Surface enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry (MS) was used to detect the time-course changes in CSF protein patterns after transient focal brain ischemia. According to hierarchical cluster analysis by self-organising tree algorism (SOTA), the temporal pattern of protein peaks was divided into four groups: acute increase group, chronic increase group, gradual decrease group and unchanged group. In the acute increase group, the expression of a 13.6-kDa protein was markedly increased during the acute phase. The 13.6-kDa protein was identified as monomeric form of transthyretin using two-dimensional electrophoresis and peptide mass fingerprinting based on matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The monomeric transthyretin may represent an ischemia-specific CSF marker to indicate the sequential changes according to ischemic insults of the brain.

More accurate identification of reversible ischemic injury in human stroke by cerebrospinal fluid suppressed diffusion-weighted imaging.

BACKGROUND AND PURPOSE: The apparent diffusion coefficient (ADC) derived from diffusion-weighted (DWI) MRI has been used to differentiate reversible from irreversible ischemic injury. However, the ADC can be falsely elevated by partial volume averaging of cerebrospinal fluid (CSF) with parenchyma, limiting the accuracy of this approach. This study tested the hypothesis that the accuracy of differentiating reversible from irreversible ischemic injury could be improved by CSF suppression at image acquisition. METHODS: Sixteen patients presenting within 6 hours from symptoms, and having partial reversal of the acute lesion on DWI were studied using conventional CSF-suppressed DWI. Lesions were segmented from coregistered acute DWI and follow-up fluid-attenuated inversion recovery (FLAIR) series. The segmented volumes were applied to conventional (ADC(C)) and CSF-suppressed ADC (ADC(FLIPD)) maps to classify each voxel as progressed to infarct or reversed. Individual voxel ADC values were pooled across all patients. Sensitivity to predict reversal, specificity, and accuracy were calculated for both methods. RESULTS: A total of 25 313 voxels were classified as progressed and 31 952 voxels reversed. Across all lesion voxels, ADC(FLIPD) values more accurately depicted tissue fate compared with ADC(C) values (P<0.0001). The largest difference in the two methods was in voxels with <75% parenchyma, where the accuracy of ADC(C) was only 50% compared with 62% for ADC(FLIPD.) CONCLUSIONS: CSF-suppressed ADC measurements gave a more accurate identification of reversible ischemic injury in this sample. We predict that multimodal MRI models of tissue viability in ischemic stroke will be more accurate if CSF-suppressed ADC measurements are used.

Complement C1q is dramatically up-regulated in brain microglia in response to transient global cerebral ischemia.

Recent evidence suggests that the pathophysiology of neurodegenerative and inflammatory neurological diseases has a neuroimmunological component involving complement, an innate humoral immune defense system. The present study demonstrates the effects of experimentally induced global ischemia on the biosynthesis of C1q, the recognition subcomponent of the classical complement activation pathway, in the CNS. Using semiquantitative in situ hybridization, immunohistochemistry, and confocal laser scanning microscopy, a dramatic and widespread increase of C1q biosynthesis in rat brain microglia (but not in astrocytes or neurons) within 24 h after the ischemic insult was observed. A marked increase of C1q functional activity in cerebrospinal fluid taken 1, 24, and 72 h after the ischemic insult was determined by C1q-dependent hemolytic assay. In the light of the well-established role of complement and complement activation products in the initiation and maintenance of inflammation, the ischemia-induced increase of cerebral C1q biosynthesis and of C1q functional activity in the cerebrospinal fluid implies that the proinflammatory activities of locally produced complement are likely to contribute to the pathophysiology of cerebral ischemia. Pharmacological modulation of complement activation in the brain may be a therapeutic target in the treatment of stroke.

Choroid plexus recovery after transient forebrain ischemia: role of growth factors and other repair mechanisms.

1. Transient forebrain ischemia in adult rats, induced by 10 min of bilateral carotid occlusion and an arterial hypotension of 40 mmHg, caused substantial damage not only to CA-1 neurons in hippocampus but also to epithelial cells in lateral ventricle choroid plexus. 2. When transient forebrain ischemia was followed by reperfusion (recovery) intervals of 0 to 12 hr, there was moderate to severe damage to many frond regions of the choroidal epithelium. In some areas, epithelial debris was sloughed into cerebrospinal fluid (CSF). Although some epithelial cells were disrupted and necrotic, their neighbors exhibited normal morphology. This patchy response to ischemia was probably due to regional differences in reperfusion or cellular metabolism. 3. Between 12 and 24 hr postischemia, there was marked restoration of the Na+, K+, water content, and ultrastructure of the choroid plexus epithelium. Since there was no microscopical evidence for mitosis, we postulate that healthy epithelial cells either were compressed together on the villus or migrated from the choroid plexus stalk to more distal regions, in order to "fill in gaps" along the basal lamina caused by necrotic epithelial cell disintegration. 4. Epithelial cells of mammalian choroid plexus synthesize and secrete many growth factors and other peptides that are of trophic benefit following injury to regions of the cerebroventricular system. For example, several growth factors are upregulated in choroid plexus after ischemic and traumatic insults to the central nervous system. 5. The presence of numerous types of growth factor receptors in choroid plexus allows growth factor mediation of recovery processes by autocrine and paracrine mechanisms. 6. The capability of choroid plexus after acute ischemia to recover its barrier and CSF formation functions is an important factor in stabilizing brain fluid balance. 7. Moreover, growth factors secreted by choroid plexus into CSF are distributed by diffusion and convection into brain tissue near the ventricular system, e.g., hippocampus. By this endocrine-like mechanism, growth factors are conveyed throughout the choroid plexus-CSF-brain nexus and can consequently promote repair of ischemia-damaged tissue in the ventricular wall and underlying brain.

Extrinsic pathway of blood coagulation and thrombin in the cerebrospinal fluid after subarachnoid hemorrhage.

OBJECTIVE: The involvement of thrombin in the pathophysiology of subarachnoid hemorrhage (SAH) was investigated by comparing thrombin expression and extrinsic pathway activation in the cerebrospinal fluid (CSF) and blood of patients with SAH with the neurological grades, outcome, and presence of delayed cerebral vasospasm. METHODS: Blood and CSF samples were obtained from 38 patients with SAH on Days 3 through 5, 7 through 9, and 12 through 14 after the onset of SAH. CSF samples were also obtained from control patients. Thrombin-antithrombin III complex, prothrombin fragment F1 +2, tissue factor, and tissue factor pathway inhibitor were analyzed using enzyme-linked immunosorbent assay. RESULTS: No markers in the blood or CSF were correlated with neurological grades and outcome. Thrombin-antithrombin III complex and prothrombin fragment F1 +2 levels were significantly higher in the CSF of patients with SAH than in the blood or the CSF of control patients and were significantly higher in patients with vasospasm than in patients without vasospasm on Days 7 through 9. Tissue factor levels were significantly higher in the CSF of patients with SAH than in the blood, but the levels were close to those in the CSF of control patients. Tissue factor pathway inhibitor levels in the CSF of patients with SAH and control patients were under the detection limit. CONCLUSION: Thrombin in the blood may not reflect the pathophysiology of SAH. Imbalance between tissue factor and tissue factor pathway inhibitor in the CSF may tend to thrombin generation under normal physiological conditions and also after SAH. Thrombin in the CSF may be involved in the pathophysiology of vasospasm.

Aggravation of acute ischemic stroke by hyperthermia is related to an excitotoxic mechanism.

OBJECTIVE: To examine whether hyperthermia aggravates cerebral injury in acute ischemia by an excitotoxic mechanism, we studied the relationship between body temperature on admission and CSF concentrations of neuroexcitatory amino acids in 128 patients with acute ischemic stroke of less than 24 h duration. METHODS: Stroke worsening was defined as the percent change between the Canadian Stroke Scale (CSS) at 48 h and the CSS on admission. Infarct volume was measured on days 4-7 on cranial computed tomography. Excitatory amino acids were analyzed using HPLC. RESULTS: Glutamate concentration [median (min.-max.)] was 11 (2-19) micromol/l in hyperthermic patients (body temperature >37.5 degreesC) and 5 (2-22) micromol/l in normothermic patients (p < 0.0001). Glycine concentration in hyperthermic and normothermic patients was 16 (3-21) micromol/l and 9 (3-50) micromol/l, respectively (p < 0.0001). Glutamate was significantly higher in patients with hyperthermia only during the first 12 h after the onset of symptoms. The CSF concentrations of glutamate (r = 0.52; p < 0.0001) and glycine (r = 0.62; p < 0.0001) correlated with body temperature. Body temperature was significantly related to stroke worsening and infarct size, but this effect was dependent on the glutamate effect. CONCLUSION: Glutamate and glycine release during the acute phase of cerebral ischemia could be responsible for the increased brain damage in hyperthermia.

Cerebrospinal fluid magnesium level as a prognostic factor in ischaemic stroke.

Magnesium has been reported to have a dilatatory effect on cerebral arteries. Reduction of extracellular Mg+2 has been shown to be directly correlated with the intensity of cerebral spasm. A neuroprotective effect of magnesium in stroke has also been hypothesized. The aim of our study was to examine the Mg+2 levels in serum and cerebrospinal fluid (CSF) in the early stage of stroke and to evaluate the correlation between Mg+2 levels and the development of neurological deficits. Between 1986 and 1994, 96 patients who had a stroke of 24- to 48-h duration were enrolled in the study. Serum and CSF levels of magnesium were checked on admission, 2448 h after the onset of stroke. Using a neurological score, the neurological deficit was assessed on the 1st day, 1 and 4 weeks later. Computed tomography (CT) was performed after 1 week, and the volume and location of infarction were calculated and measured. Statistical analysis was performed for cortical and subcortical patients separately, using Spearman correlation and multiple linear and logistic regression analyses. Significant correlation was found between CSF Mg+2 and the size of the infarct (P < 0.0001). There was no correlation between serum Mg+2 and CSF Mg+2 levels. Regression analysis demonstrated an increase in the values of the Mathew Neurological Score with higher CSF Mg+2 levels. This association remained true after other factors such as age, associated heart disease, diabetes and infarction size had been taken into account by the regression model. The results confirm that there is a relationship between a low Mg+2 concentration in CSF during the first 48 h after onset of ischaemic stroke and the intensity of the neurological deficit. The therapeutic consequence of this finding may have some importance.

Detection of soluble E-selectin, ICAM-1, VCAM-1, and L-selectin in the cerebrospinal fluid of patients after subarachnoid hemorrhage.

OBJECT: The goal of this study was to explore whether the levels of soluble adhesion molecules were elevated in cerebrospinal fluid (CSF) after subarachnoid hemorrhage (SAH). This association was suggested by the known inflammatory response in vasospasm and the role of vascular adhesion molecules in regulating leukocytic adhesion to, and migration across, vascular endothelium. METHODS: A prospective analysis was performed on CSF samples obtained in 17 patients who had suffered a recent aneurysmal SAH and in 16 control patients by using quantitative enzyme-linked immunosorbent assays for E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and L-selectin. Levels of soluble forms of E-selectin (p=0.0013), ICAM-1 (p=0.0001), and VCAM-1 (p=0.048) were found to be elevated in the CSF of patients after SAH compared with levels in the CSF of norminal controls, patients with unruptured aneurysms, and patients tested months after SAH occurred. In addition, individual patients tested at the time of their initial ictus demonstrated a fall in adhesion molecule levels over time. Levels of E-selectin (p=0.044) were highest in patients who later developed moderate or severe vasospasm. CONCLUSIONS: Adhesion molecules are known to be involved in white cell adherence to the endothelium and subsequent diapedesis and migration in which a role in initiation of tissue damage is postulated. The authors have demonstrated the elevation of three adhesion molecules, with severely elevated levels of E-selectin seen in patients who later develop vasospasm. A correlation with a role of vascular adhesion molecules in the pathogenesis of cerebral vasospasm is suggested.

Cisternal CSF levels of cytokines after subarachnoid hemorrhage.

Cytokines are considered as mediators of immune and inflammatory responses. Cisternal CSF levels of interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1) and of the soluble adhesion molecule E-selectin were evaluated in patients operated on for intracranial aneurysms. Cisternal CSF samples were obtained at surgery in 41 selected patients (31 with diagnosis of subarachnoid hemorrhage (SAH) and 10 control patients operated on for incidental unruptured aneurysms); 14 patients were operated within 72 h after SAH (early surgery) and 17 were operated after day 10 after the hemorrhage (delayed surgery). The CSF levels of cytokines were evaluated using radioimmunoassay and their concentrations were related to the timing of surgery, the amount of cisternal subarachnoid blood clots and the onset of clinical and angiographical evidence of arterial vasospasm. Mean cisternal CSF levels of IL-6, IL-8 and AMCP-1 are significantly higher in samples obtained from patients early operated after SAH, while levels of E-selectin were below the threshold value of the method in all 41 cases. In the early operated group 7 patients presented symptomatic vasospasm: levels of IL-8 and MCP-1 were not significantly different were compared to those of uncomplicated cases; on the other hand, significantly higher levels of IL-6 were shown in the subgroup of patients operated within 72 h after SAH and developing vasospasm. Among the patients undergoing delayed surgery 5 presented symptomatic vasospasm, but no significant difference was shown in cisternal CSF levels of cytokines measured. The results of the present study show that in patients with unruptured aneurysms cytokines are present in cisternal CSF in scarce quantities and that in subarachnoid spaces after SAH there is an impressive increase of IL-6, IL-8 and MCP-1. Moreover, the higher cisternal CSF levels of IL-6 found in the early stage after SAH might have a predictive value regarding the occurrence of symptomatic vasospasm.

Coagulative and fibrinolytic activation in cerebrospinal fluid and plasma after subarachnoid hemorrhage.

OBJECTIVE: Intrathecal fibrinolytic therapy has been used as one of the anticerebral vasospasm (VS) preventative therapies in patients with subarachnoid hemorrhage (SAH). However, the changes in coagulation and fibrinolysis in the blood and cerebrospinal fluid (CSF) after SAH remain unknown. METHODS: Fifty patients with SAH caused by ruptured cerebral aneurysms were studied postoperatively to detect the serial changes of the thrombin-antithrombin III complex, active plasminogen activator inhibitor (PAI)-1, and tissue plasminogen activator (tPA)-PAI complex (tPA-PAI) activities in the plasma and CSF collected from cisternal drainage catheters. RESULTS: The CSF levels of all parameters and plasma PAI-1 levels were significantly higher in patients with severe SAH than in those with mild SAH. There was no relationship between the CSF and plasma levels of these parameters (except the CSF levels of tPA-PAI) and the initial neurological statuses. The CSF PAI-1 levels increased to greater than 20 ng/ml near the time of the occurrence of cerebral VS, whereas they remained below 20 ng/ml in patients without VS. The CSF tPA-PAI levels showed the highest peak near the time of VS remission. The CSF PAI-1 and tPA-PAI levels were significantly lower in patients with good outcomes than in those with poor outcomes. CONCLUSION: Both the coagulative and fibrinolytic systems were activated in the CSF and plasma after SAH in correlating to the amount of SAH clot. The intrathecal administration of fibrinolytic agents should be started early after surgery, before CSF PAI-1 levels increase, for patients with severe SAH. Patients with CSF PAI-1 levels greater than 20 ng/ml experienced high incidence of VS and poor outcomes.

Endothelin in cerebral vasospasm. Clinical and experimental results.

Since their discovery in 1988, endothelins have attracted scientific interest because of their extremely potent and long lasting vasoconstrictive effects. In the clinical part of the study plasma and cerebrospinal fluid (CSF) concentrations of big endothelin-1, endothelin-1 and endothelin-3 in patients with aneurysmal subarachnoid hemorrhage (SAH) were measured serially for 2 weeks after the onset of SAH. Big endothelin-1 was the predominant peptide present in CSF. The CSF concentrations of big ET-1, ET-1 and ET-3 were significantly higher in older than in younger patients. In patients with cerebral vasospasm postoperative concentrations of endothelins in the CSF remained at or were increased above levels measured before surgery. The volume of hematoma in the basal cisterns was predictive of the concentrations of endothelins in CSF. In the experimental study the efficacy of the orally active endothelin-receptor-antagonist RO 47-0203 for the prevention of cerebral vasospasm after experimental SAH, using the canine two-hemorrhage model, was investigated. Twenty-eight beagle dogs were used in this laboratory experiment. Fourteen animals each were assigned to the treatment and to the control group. In the treatment group each dog received two single doses of 30 mg/kg RO 47-0203 orally per day. The diameter of the basilar artery decreased from 1.36 +/- 0.17 mm at day 1 to 1.19 +/- 0.23 mm at day 8 in the treatment group while in the control group the vessel diameter decreased from 1.48 +/- 0.19 mm at day 1 to 1.02 +/- 0.22 mm at day 8. These results corresponded to a decrease of vessel diameter of 13.1% +/- 11.2% in the treatment group and a decrease of vessel diameter of 30.7% +/- 12.4% in the control group (p < 0.001). Concentrations of endothelin-1 in CSF significantly increased with time after SAH. These results underline the important role of endothelin in the development of cerebral vasospasm, and gives for the first time evidence that prevention of cerebral vasospasm can be achieved by the endothelin-receptor-antagonist RO 47-0203.

Effects of halothane, alpha-chloralose, and pCO2 on injury volume and CSF beta-endorphin levels in focal cerebral ischemia.

Anesthetic agent, arterial pCO2 level, and opioid peptides have all been implicated in the pathophysiology of experimental stroke models. The effects of halothane, alpha-chloralose, and differing concentrations of arterial pCO2 on injury volume and CSF beta-endorphin levels were studied in a feline model of experimental focal cerebral ischemia. The type of anesthetic agent used had no effect on injury volume following 6 h of focal cerebral ischemia. Over a 6-h period, beta-endorphin levels significantly increased from 10.1 +/- 5.0 fmol/mL at zero time to 14.4 +/- 7.2 fmol/mL at 6 h under halothane anesthesia (p < 0.05), whereas they did not significantly change (10.1 +/- 6.7 to 7.8 +/- 4.7 fmol/mL) under alpha-chloralose anesthesia. In contrast, hypercapnia had no effect on beta-endorphin levels, but significantly increased injury volume from 30.6 +/- 5.7% of the ipsilateral hemisphere under normocapnic conditions to 37.1 +/- 5.9% under hypercapnic conditions (p < 0.05). These results suggest that hypercapnia increases injury volume in a feline model of focal cerebral ischemia, and pCO2 should be controlled in experimental focal cerebral ischemia models.

Endothelin concentrations in patients with aneurysmal subarachnoid hemorrhage. Correlation with cerebral vasospasm, delayed ischemic neurological deficits, and volume of hematoma.

Plasma and cerebrospinal fluid (CSF) concentrations of endothelin (ET)-1, ET-3, and big ET-1 in patients with aneurysmal rupture were measured serially for 2 weeks after the onset of aneurysmal subarachnoid hemorrhage (SAH) and compared with levels of ETs in patients without SAH and the plasma concentrations of ETs in normal volunteers. Big ET-1 was the predominant peptide present in the CSF of SAH patients. The CSF concentrations of big ET-1, ET-1, and ET-3 were significantly higher in older patients than in younger patients. In SAH patients with cerebral vasospasm (CVS) documented by transcranial Doppler sonography and clinical signs, postoperative concentrations of ETs in the CSF remained at or were increased above levels measured before surgery. In SAH patients without CVS, the concentrations of ETs in the CSF decreased with time, whereas the time course of CVS coincided with the increase in concentrations of big ET-1 and ET-1. The temporal dependence of concentrations of big ET-1 and ET-1 in SAH patients with and without CVS were significantly different. The volume of hematoma in the basal cisterns as detected by computerized tomography was predictive of the concentrations of ETs in the CSF. Plasma concentrations of ETs were not correlated with CVS. The possible role of ETs in the pathogenesis of CVS associated with SAH and the controversial data reported to date are discussed.

Alterations in perivascular dilatory neuropeptides (CGRP, SP, VIP) in the external jugular vein and in the cerebrospinal fluid following subarachnoid haemorrhage in man.

A possible involvement of perivascular vasodilatory neuropeptides in subarachnoid haemorrhage (SAH) has been evaluated in man by measuring the levels of calcitonin gene related peptide (CGRP)-, substance P (SP)- and vasoactive intestinal peptide (VIP)-like immunoreactivity (LI) in the cranial venous outflow and in CSF in 34 patients admitted to the hospital after an acute SAH. After operation with aneurysm clipping and nimodipine treatment, blood samples were taken from the external jugular vein (EJV) or cerebrospinal fluid (CSF) and analysed for neuropeptide levels with specific radioimmuno assays (RIA) during the postoperative course. The degree of vasoconstriction in the patients was monitored with Doppler ultrasound recordings bilaterally from the middle cerebral (MCA) and internal carotid arteries (ICA) following the EJV blood sampling every second day. The mean value of all CGRP-LI measurements in EJV during the entire course of SAH (n = 20) revealed a significantly higher level as compared to controls. The highest CGRP-LI levels were found in patients with the highest velocity index values (vasospasm). The relationship Vmean MCA/Vmean ICA was used as an index of vasoconstriction. In patients with MCA aneurysms (n = 10), a significant correlation (r = 0.65, p < 0.05) was found between the vasospasm index and CGRP-LI levels. There were no changes observed in the SP- and VIP-LI levels. Alterations in cerebrovascular tone induced by changing arterial CO2 tension or lowering of blood pressure (ketanserin infusion test) did not alter the levels of the perivascular peptides in the EJV. In addition, CGRP-, SP-, VIP- and neuropeptide Y (NPY)-LI were analysed in CSF in the post-operative course after subarachnoid haemorrhage (SAH) in 14 patients. The CSF VIP-LI was lower in SAH than in control (p < 0.05). The CGRP-LI level was measurable in SAH CSF but not in CSF of controls. In individual patients with marked vasoconstriction increased levels of CGRP-LI (up to 14 pmol/L) and NPY-LI (up to 232 pmol/L) were observed. The results of this study are in support of our hypothesis that there is an involvement of the sensory peptide CGRP in a dynamic reflex aimed at counterbalancing vasoconstriction in SAH.