Neurosurgical Center Amsterdam

Amsterdam, Netherlands

Neurosurgical Center Amsterdam

Amsterdam, Netherlands

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Germans M.R.,Neurosurgical Center Amsterdam | Coert B.A.,Neurosurgical Center Amsterdam | Nijeholt G.L.,Medical Center Haaglanden | Rinkel G.J.E.,University Utrecht | And 2 more authors.
Neurology | Year: 2015

Objective: We studied the yield of MRI of the spinal neuraxis in patients with nonperimesencephalic subarachnoid hemorrhage (NPSAH). Methods: In a prospective, multicenter study, we performed T1-weighted and T2-weighted MRI of the spinal axis in a consecutive series of patients with a spontaneous NPSAH without intracranial vascular pathology on intracranial vascular imaging. Results: A spinal origin of the hemorrhage was found in 3 of 75 patients (4%; 95% confidence interval 0-8.4). The lesions were 1 lumbar ependymoma and 2 cervical cavernous malformations. All 3 patients presented without focal neurologic deficits and 2 had a CT-negative subarachnoid hemorrhage but positive lumbar puncture. Patients with a spinal origin were younger than patients without a spinal origin (38 vs 56 years; p , 0.05), which was the only significant difference between groups. Conclusions: The yield and clinical relevance of MRI of the spinal axis in patients who present with NPSAH is low. We do not recommend routine MRI of the spinal axis in this patient population, but it might be justified in a subgroup of patients. © 2015 American Academy of Neurology.


Molenaar R.J.,University of Amsterdam | Verbaan D.,Neurosurgical Center Amsterdam | Lamba S.,University of Turin | Zanon C.,University of Turin | And 18 more authors.
Neuro-Oncology | Year: 2014

Background. Genetic and epigenetic profiling of glioblastomas has provided a comprehensive list of altered cancer genes of which only O6- methylguanine-methyltransferase (MGMT) methylation is used thus far as a predictive marker in a clinical setting. We investigated the prognostic significance of genetic and epigenetic alterations in glioblastoma patients. Methods. We screened 98 human glioblastoma samples for genetic and epigenetic alterations in 10 genes and chromosomal loci by PCR and multiplex ligation-dependent probe amplification (MLPA). We tested the association between these genetic and epigenetic alterations and glioblastoma patient survival. Subsequently, we developed a 2-gene survival predictor. Results. Multivariate analyses revealed that mutations in isocitrate dehydrogenase 1 (IDH1), promoter methylation of MGMT, irradiation dosage, and Karnofsky Performance Status (KFS) were independent prognostic factors. A 2-gene predictor for glioblastoma survival was generated. Based on the genetic and epigenetic status of IDH1 and MGMT, glioblastoma patients were stratified into 3 clinically different genotypes: glioblastoma patients with IDH1 mt/ MGMTmet had the longest survival, followed by patients with IDH1 mt/MGMTunmet or IDH1wt/MGMTmet, and patients with IDH1wt/ MGMTunmet had the shortest survival. This 2-gene predictor was an independent prognostic factor and performed significantly better in predicting survival than either IDH1 mutations or MGMT methylation alone. The predictor was validated in 3 external datasets. Discussion. The combination of IDH1 mutations and MGMT methylation outperforms either IDH1 mutations or MGMT methylation alone in predicting survival of glioblastoma patients. This information will help to increase our understanding of glioblastoma biology, and it may be helpful for baseline comparisons in future clinical trials. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved.


PubMed | Neurosurgical Center Amsterdam, University Utrecht and University of Groningen
Type: Journal Article | Journal: Neurocritical care | Year: 2016

Delayed cerebral ischemia (DCI) is an important contributor to poor outcome after aneurysmal subarachnoid haemorrhage (aSAH). Development of DCI is multifactorial, and inflammation, with or without infection, is one of the factors independently associated with development of DCI and poor outcome. We thus postulated that preventive antibiotics might be associated with a reduced risk of DCI and subsequent poor outcome in aSAH patients.We performed a retrospective cohort-study in intensive care units (ICU) of three university hospitals in The Netherlands. We included consecutive aSAH patients with minimal ICU stay of 72 h who received either preventive antibiotics (SDD: selective digestive tract decontamination including systemic cefotaxime or SOD: selective oropharyngeal decontamination) or no preventive antibiotics. DCI was defined as a new hypodensity on CT with no other explanation than DCI. Hazard ratios (HR) for DCI and risk ratios (RR) for 28-day case-fatality and poor outcome at 3 months were calculated, with adjustment (aHR/aRR) for clinical condition on admission, recurrent bleeding, aneurysm treatment modality and treatment site.Of 459 included patients, 274 received preventive antibiotics (SOD or SDD) and 185 did not. With preventive antibiotics, the aHR for DCI was 1.0 (95% CI 0.6-1.8), the aRR for 28-day case-fatality was 1.1 (95% CI 0.7-1.9) and the aRR for poor functional outcome 1.2 (95% CI 1.0-1.4).Preventive antibiotics were not associated with reduced risk of DCI or poor outcome in aSAH patients in the ICU.


Van Zanten S.E.M.V.,VU University Amsterdam | Jansen M.H.,VU University Amsterdam | Sanchez Aliaga E.,VU University Amsterdam | Van Vuurden D.G.,VU University Amsterdam | And 2 more authors.
Expert Review of Anticancer Therapy | Year: 2015

Introduction: Children with diffuse intrinsic pontine glioma (DIPG) face a dismal prognosis, with a median overall survival of 9 months. Our aims are to determine the incidence of DIPG in the Netherlands and to identify points for improvement in clinical research, a prerequisite for increasing the chance to find a cure. Methods: We performed a population-based retrospective cohort study by evaluating all children diagnosed with DIPG in the Netherlands between 1990 and 2010. Results: The incidence of DIPG in the Netherlands corresponds with international literature. Between 1990 and 2010, a large heterogeneity of treatment schedules was applied and only a minority of patients was included in clinical trials. Discussion: Given the rarity of DIPG, we emphasize the need for (inter-)national trials to facilitate the identification of potentially effective therapeutics in the future. This can be supported by the recent development of a European DIPG registry enabling international study collaborations. © 2014 Informa UK, Ltd.


Germans M.R.,Neurosurgical Center Amsterdam | Post R.,Neurosurgical Center Amsterdam | Coert B.A.,Neurosurgical Center Amsterdam | Rinkel G.J.E.,University Utrecht | And 2 more authors.
Trials | Year: 2013

Background: A frequent complication in patients with subarachnoid hemorrhage (SAH) is recurrent bleeding from the aneurysm. The risk is highest within the first 6 hours after the initial hemorrhage. Securing the aneurysm within this timeframe is difficult owing to logistical delays. The rate of recurrent bleeding can also be reduced by ultra-early administration of antifibrinolytics, which probably improves functional outcome. The aim of this study is to investigate whether ultra-early and short-term administration of the antifibrinolytic agent tranexamic acid (TXA), as add-on to standard SAH management, leads to better functional outcome.Methods/Design: This is a multicenter, prospective, randomized, open-label trial with blinded endpoint (PROBE) assessment. Adult patients with the diagnosis of non-traumatic SAH, as proven by computed tomography (CT) within 24 hours after the onset of headache, will be randomly assigned to the treatment group or the control group. Patients in the treatment group will receive standard treatment with the addition of a bolus of TXA (1 g intravenously) immediately after randomization, followed by continuous infusion of 1 g per 8 hours until the start of aneurysm treatment, or a maximum of 24 hours after the start of medication. Patients in the control group will receive standard treatment without TXA. The primary outcome measure is favorable functional outcome, defined as a score of 0 to 3 on the modified Rankin Scale (mRS), at 6 months after SAH. Primary outcome will be determined by a trial nurse blinded for treatment allocation. We aim to include 950 patients in 3 years.Discussion: The strengths of this study are: 1. the ultra-early and short-term administration of TXA, resulting in a lower dose as compared to previous studies, which should reduce the risk for delayed cerebral ischemia (DCI), an important risk factor in the long-term treatment with antifibrinolytics; 2. the power calculation is based on functional outcome and calculated with use of recent study results of our own population, supported by data from prominent studies; and 3. the participation of several specialized SAH centers, and their referring hospitals, in the Netherlands with comparative treatment protocols.Trial registration: Nederlands Trial Register (Dutch Trial Registry) number NTR3272. © 2013 Germans et al.; licensee BioMed Central Ltd.


Germans M.R.,Neurosurgical Center Amsterdam | Coert B.A.,Neurosurgical Center Amsterdam | Vandertop W.P.,Neurosurgical Center Amsterdam | Verbaan D.,Neurosurgical Center Amsterdam
Journal of Neurology | Year: 2014

The most threatening early complication and predictor of poor outcome after an aneurysmal subarachnoid hemorrhage (aSAH) is a rebleed. To evaluate what proportion of rebleeds might be prevented by early treatment, we assessed the time interval from the initial hemorrhage to rebleed, and the location of the patient at the time of rebleed. Patient characteristics, World Federation of Neurological Surgeons grade on admission and modified Rankin Scale outcome scores, referring hospitals and time intervals from initial hemorrhage to treatment of 293 patients treated between 2008 and 2011 were evaluated. Time intervals to rebleeds and location of the patients at the time of rebleed were retrieved. Rebleeds were confirmed by CT in 12 % of patients, and an additional 4 % of patients was diagnosed as having a possible rebleed. Sixty percent of rebleeds occurred after admission to the treatment center. Almost all rebleeds occurred within 24 h, with a median time interval between initial hemorrhage and rebleed of 180 min. A significantly shorter time to treatment and a higher mortality were seen in the group of patients with a rebleed. Approximately, one in six patients with an aSAH had a rebleed, of which a majority might have been preventable because they occurred after admission to the treatment center. A reduction in the rebleed rate seems feasible by securing the aneurysm as soon as possible by improving in-hospital logistics for early aneurysm treatment. Alternative options, such as immediate administration of antifibrinolytics, are being explored in a multicenter trial. © 2014 Springer-Verlag Berlin Heidelberg.


Bleeker F.E.,Neurosurgical Center Amsterdam | Molenaar R.J.,University of Amsterdam | Leenstra S.,Erasmus Medical Center
Journal of Neuro-Oncology | Year: 2012

Glioblastoma is the most common and most aggressive primary brain tumor. Despite maximum treatment, patients only have a median survival time of 15 months, because of the tumor's resistance to current therapeutic approaches. Thus far, methylation of the O 6-methylguanine-DNA methyltransferase (MGMT) promoter has been the only confirmed molecular predictive factor in glioblastoma. Novel "genome-wide" techniques have identified additional important molecular alterations as mutations in isocitrate dehydrogenase 1 (IDH1) and its prognostic importance. This review summarizes findings and techniques of genetic, epigenetic, transcriptional, and proteomic studies of glioblastoma. It provides the clinician with an up-to-date overview of current identified molecular alterations that should ultimately lead to new therapeutic targets and more individualized treatment approaches in glioblastoma. © 2012 The Author(s).


Smits M.,Cancer Center Amsterdam | Wurdinger T.,Cancer Center Amsterdam | Wurdinger T.,Harvard University | Van Het Hof B.,Blood Brain Barrier Research Group | And 9 more authors.
FASEB Journal | Year: 2012

In patients with glioblastomas, vascular endothelial growth factor (VEGF) is a key mediator of tumor-associated angiogenesis. Glioblastomas are notorious for their capacity to induce neovascularization, driving continued tumor growth. Here we report that miR-125b is down-regulated in glioblastoma-associated endothelial cells, resulting in increased expression of its target, myc-associated zinc finger protein (MAZ), a transcription factor that regulates VEGF. The down-regulation of miR-125b was also observed on exposure of endothelial cells to glioblastoma-conditioned medium or VEGF, resulting in increased MAZ expression. Further analysis revealed that inhibition of MAZ accumulation by miR-125b, or by MAZ-specific shRNAs, attenuated primary human brain endothelial cell migration and tubule formation in vitro, phenomena considered to mimick angiogenic processes in vitro. Moreover, MAZ expression was elevated in brain blood vessels of glioblastoma patients. Altogether these results demonstrate a functional feed-forward loop in glioblastomarelated angiogenesis, in which VEGF inhibits the expression of miR-125b, resulting in increased expression of MAZ, which in its turn causes transcriptional activation of VEGF. This loop is functionally impeded by the VEGF receptor inhibitor vandetanib, and our results may contribute to the further development of inhibitors of tumor-angiogenesis. © FASEB.


Smits M.,VU University Amsterdam | Van Rijn S.,VU University Amsterdam | Hulleman E.,VU University Amsterdam | Biesmans D.,VU University Amsterdam | And 9 more authors.
Clinical Cancer Research | Year: 2012

Purpose: Medulloblastoma is the most common malignant brain tumor in children. Despite recent improvements, the molecular mechanisms driving medulloblastoma are not fully understood and further elucidation could provide cues to improve outcome prediction and therapeutic approaches. Experimental Design: Here, we conducted a meta-analysis of mouse and human medulloblastoma gene expression data sets, to identify potential medulloblastoma tumor suppressor genes. Results: We identified DAB2IP, a member of the RAS-GTPase-activating protein family (RAS GAP), and showed that DAB2IP expression is repressed in medulloblastoma by EZH2-induced trimethylation. Moreover, we observed that reduced DAB2IP expression correlates significantly with a poor overall survival of patients with medulloblastoma, independent of metastatic stage. Finally, we showed that ectopic DAB2IP expression enhances stress-induced apoptosis in medulloblastoma cells and that reduced expression of DAB2IP in medulloblastoma cells conveys resistance to irradiation-induced cell death. Conclusion: These results suggest that repression of DAB2IP may at least partly protect medulloblastoma cells from apoptotic cell death. Moreover, DAB2IP may represent a molecular marker to distinguish patients with medulloblastoma at high risk from those with a longer survival prognosis. ©2012 AACR.


Van Alkemade H.,University of Amsterdam | Van Alkemade H.,Neurosurgical Center Amsterdam | De Leau M.,University of Amsterdam | De Leau M.,Neurosurgical Center Amsterdam | And 6 more authors.
Neuro-Oncology | Year: 2012

Purpose: To assess long-term functional outcome and survival among patients with meningioma World Health Organization (WHO) grade I. Methods: Retrospective analysis of 205 patients after resection of WHO grade I intracranial meningioma from 1985 through 2003. Expected age-and sex-specific survival was calculated by applying Dutch life-table statistics to each patient for the individual duration of follow-up. Long-term functional outcome was assessed using a mailed questionnaire to the general practitioner. Results: The mean duration of follow-up was 11.5 years. Survival at 5, 10, 15, and 20 years was 92%,81%, 63%, and 53%respectively, which is significantly lower than the expected survival (94%, 86%, 78%, and 66%, respectively). Survival was worse with higher age (P < .001). Survival among patients younger than 45 years and older than 65 years was comparable to the expected survival but significantly worse among patients aged 45-65 years. Analysis of the cause of death suggests an excess mortality associated with both brain tumor death and stroke (P =.07). Recurrence rates at 5, 10, and 15 years were 18%, 26%, and 32%, respectively. Higher Simpson grade (P < .001) and lower age (P = .02) were associated with a higher recurrence rate. In 29 patients (14%) receiving radiotherapy, the 5-year recurrence rate was 18% and the 5-year survival was only 58%. Long-term functioning (≤5 years after last treatment) could be assessed in 89 long-term survivors: 29 patients (33%) showed no deficits, and 60 (67%) showed at least 1 neurological symptom, of whom 24 (27%) were unable to perform normal daily activities. Conclusion: Long-term survival in WHO grade I meningioma is challenged in patients more than45 years of age. Excess mortality seems to be associated with both tumor recurrence and stroke. The majority of patients have long-term neurological problems. © 2012 The Author(s).

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