A noninvasive estimation of cerebral perfusion pressure using critical closing pressure.

OBJECT: Cerebral blood flow is associated with cerebral perfusion pressure (CPP), which is clinically monitored through arterial blood pressure (ABP) and invasive measurements of intracranial pressure (ICP). Based on critical closing pressure (CrCP), the authors introduce a novel method for a noninvasive estimator of CPP (eCPP). METHODS: Data from 280 head-injured patients with ABP, ICP, and transcranial Doppler ultrasonography measurements were retrospectively examined. CrCP was calculated with a noninvasive version of the cerebrovascular impedance method. The eCPP was refined with a predictive regression model of CrCP-based estimation of ICP from known ICP using data from 232 patients, and validated with data from the remaining 48 patients. RESULTS: Cohort analysis showed eCPP to be correlated with measured CPP (R = 0.851, p < 0.001), with a mean ± SD difference of 4.02 ± 6.01 mm Hg, and 83.3% of the cases with an estimation error below 10 mm Hg. eCPP accurately predicted low CPP (< 70 mm Hg) with an area under the curve of 0.913 (95% CI 0.883-0.944). When each recording session of a patient was assessed individually, eCPP could predict CPP with a 95% CI of the SD for estimating CPP between multiple recording sessions of 1.89-5.01 mm Hg. CONCLUSIONS: Overall, CrCP-based eCPP was strongly correlated with invasive CPP, with sensitivity and specificity for detection of low CPP that show promise for clinical use.G. Varsos is supported by an A. G. Leventis Foundation Scholarship and a Charter Studentship from St. Edmund’s College, Cambridge. Dr. Kolias is supported by a Royal College of Surgeons of England Research Fellowship, a National Institute for Health Research (NIHR) Academic Clinical Fellowship, and a Raymond and Beverly Sackler Studentship. He also chairs the British Neurosurgical Trainee Research Collaborative, which has been supported with an educational grant from Codman. Dr. Hutchinson is supported by an NIHR Research Professorship, the NIHR Cambridge Biomedical Research Centre, and has been appointed as the Surgical Specialty Lead for Neurosurgery, Royal College of Surgeons of England Clinical Research Initiative. He is a director of Technicam, a manufacturer of cranial access devices for neuromonitoring. He has also received honoraria from Codman. J. Pickard’s research (excluding salary) is supported by the NIHR Cambridge Biomedical Research Centre and an NIHR Senior Investigator Award. ICM+ Software is licensed by Cambridge Enterprise, Cambridge, UK, and Dr. Czosnyka and Dr. Smielewski have a financial interest in a fraction of the licensing fee. Dr. Czosnyka has also served as a consultant to Codman.This is the author accepted manuscript. The final version is available from American Association of Neurological Surgeons via http://dx.doi.org/10.3171/2014.10.JNS14613

Cerebral vasospasm affects arterial critical closing pressure.

The effect of cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (SAH) on critical closing pressure (CrCP) has not been fully delineated. Using cerebral impedance methodology, we sought to assess the behavior of CrCP during CVS. As CrCP expresses the sum of intracranial pressure (ICP) and vascular wall tension, we also explored its role in reflecting changes in vascular tone occurring in small vessels distal to spasm. This retrospective analysis was performed using recordings from 52 patients, diagnosed with CVS through transcranial Doppler measurements. Critical closing pressure was calculated noninvasively using arterial blood pressure and blood flow velocity. Outcome was assessed at both discharge and 3 months after ictus with the Glasgow Outcome Scale. The onset of CVS caused significant decreases in CrCP (P=0.025), without any observed significant changes in ICP (P=0.134). Vasospasm induced asymmetry, with CrCP ipsilateral to CVS becoming significantly lower than contralateral (P=0.025). Unfavorable outcomes were associated with a significantly lower CrCP after the onset of CVS (discharge: P=0.014; 3 months after SAH: P=0.020). Critical closing pressure is reduced in the presence of CVS in both temporal and spatial assessments. As ICP remained unchanged during CVS, reduced CrCP most probably reflects a lower wall tension in dilated small vessels distal to spasm.GVV is supported by an A.G. Leventis Foundation Scholarship, and a Charter Studentship from St Edmund’s College, Cambridge. AGK is supported by a Royal College of Surgeons of England Research Fellowship, a National Institute for Health Research (NIHR) Academic Clinical Fellowship, and a Raymond and Beverly Sackler Studentship. JD is supported by a Woolf Fisher Trust scholarship. PJH is supported by an NIHR Research Professorship, the NIHR Cambridge Biomedical Research Centre and has been appointed as the Surgical Specialty Lead for Neurosurgery, Royal College of Surgeons of England Clinical Research Initiative. JDP and MC are supported by the NIHR Cambridge Biomedical Research Centre and JDP by NIHR Senior Investigator Award. The prospective study16 on which this retrospective analysis was based, was supported by the National Institute of Health Research, Biomedical Research Centre (Neuroscience Theme). MC was supported by NIHR Cambridge Biomedical Research Centre.This is the accepted manuscript. The final published version is available from Nature Publishing at http://www.nature.com/jcbfm/journal/vaop/ncurrent/full/jcbfm2014198a.html

Simultaneous occurrence of cerebellar medulloblastoma and pituitary adenoma: A case report

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Construction of experimental “giant” aneurysms

Giant aneurysms were produced in dogs by initially producing a fistula between the common carotid artery and the external jugular vein. One week later the vein was ligated above and below the fistula to create a blind aneurysmal pouch. This model has been found useful in testing experimental techniques of aneurysmal obliteration by direct injection into the sac while the lumen of the parent vessel is temporarily protected by an endovascular balloon inflated at the neck of the aneurysm

Obliteration of experimental aneurysms in dogs with isobutyl-cyanoacrylate

✓ Experimental cervical carotid aneurysms in dogs are obliterated with isobutyl-cyanoacrylate (IBCA) injected under direct vision into the aneurysm. Reflux of IBCA into the artery was prevented by inflating either a latex or a Silastic balloon in the carotid artery at the level of the neck of the aneurysm. This balloon was introduced through a catheter advanced into the common carotid artery by femoral catheterization. The Silastic balloon was found to be much more effective than the latex balloon in preventing spillage of IBCA into the lumen

Complex interactions between the components of the PI3K/AKT/mTOR pathway, and with components of MAPK, JAK/STAT and Notch-1 pathways, indicate their involvement in meningioma development

International audienceWe investigated the significance of PI3K/AKT/mTOR pathway and its interactions with MAPK, JAK/STAT and Notch pathways in meningioma progression. Paraffin-embedded tissue from 108 meningioma patients was analysed for the presence of mutations in PIK3CA and AKT1. These were correlated with the expression status of components of the PI3K/AKT/mTOR pathway, including p85 alpha and p110 gamma subunits of PI3K, phosphorylated (p)-AKT, p-mTOR, p-p70S6K and p-4E-BP1, as well as of p-ERK1/2, p-STAT3 and Notch-1, clinicopathological data and patient survival. A mutation in PIK3CA or AKT1 was found in around 9 % of the cases. Higher grade meningiomas displayed higher nuclear expression of p-p70S6K; higher nuclear and cytoplasmic expression of p-4E-BP1 and of Notch-1; lower cytoplasmic expression of p85 alpha PI3K, p-p70S6K and p-ERK1/2; and lower PTEN Histo-scores (H-scores). PTEN H-score was inversely correlated with recurrence probability. In univariate survival analysis, nuclear expression of p-4E-BP1 and absence of p-ERK1/2 expression portended adverse prognosis, whereas in multivariate survival analysis, p-ERK1/2 expression emerged as an independent favourable prognostic factor. Treatment of the human meningioma cell line HBL-52 with the PI3K inhibitor LY294002 resulted in reduction of p-AKT, p-p70S6K and p-ERK1/2 protein levels. The complex interactions established between components of the PI3K/AKT/mTOR pathway, or with components of the MAPK, JAK/STAT and Notch-1 pathways, appear to be essential for facilitating and fuelling meningioma progression