Biomedical subjects

Vera van Velthoven

Publications and source records attributed to Vera van Velthoven.

8 recordsLinked to original sources

PubMed2006

K(+)-evoked [(3)H]-norepinephrine release in human brain slices from epileptic and non-epileptic patients is differentially modulated by gabapentin and pinacidil.

The modulation of K(+)-evoked [(3)H]-norepinephrine ([(3)H]-NE) release by gabapentin (GBP) and pinacidil (PIN), a known K(ATP) agonist, was examined in human brain slices. We compared the pharmacological effects on NE-release in human epileptic neocortex and epileptic hippocampus to non-epileptic neocortex. GBP (100 microM) decreased [(3)H]-NE release by 22% in non-epileptic neocortical slices, whereas this inhibition was absent in slices from epileptic hippocampus and epileptic neocortex. PIN (10 microM) also reduced [(3)H]-NE release by 30% in non-epileptic neocortical slices and only by 5% in epileptic hippocampal slices. The blockade of voltage-gated calcium channels by omega-conotoxins MVIIA and MVIIC (0.1 microM) reduced [(3)H]-NE release in epileptic and non-epileptic neocortical slices to the same extend. The data show a marked reduction in K(+)-evoked [(3)H]-NE release by GBP and PIN in epileptic hippocampus and neocortex, suggesting an alteration of K(ATP) channel function, whereas the effects of the calcium channel modulators omega-conotoxins MVIIA and MVIIC are similar in both epileptic and non-epileptic neocortex.

Adrenergic alpha-Agonists↗

PubMed2006

Coating the wall of an injured intracranial carotid artery during tumor removal with n-butyl-2-cyanoacrylate: technical case report.

OBJECTIVE: Carotid artery injury close to the clinoid process is difficult to repair, and is even more so when the vessel is firmly attached to a calcified tumor. We treated a patient with an intraoperative carotid lesion by coating the vessel wall with n-butyl-2-cyanoacrylate (NBCA). CLINICAL PRESENTATION: A 7-year-old boy was referred to our clinic with a 3-month history of somnolence, apathy, and headache. Neurological examination revealed bitemporal hemianopsia. The cranial magnetic resonance imaging and computed tomographic scans showed a sellar and suprasellar calcified mass with heterogeneous contrast enhancement, a cyst component in the upper part of the tumor displaced upward and back from the mesencephalic and diencephalic structures. INTERVENTION: The patient underwent a pterional craniotomy. Using a microsurgical technique, the suprasellar part of the craniopharyngioma was removed. In an attempt to dissect the calcified mass from the carotid artery on the right side, the vessel was unintentionally injured, followed by severe bleeding. Temporary occlusion and suturing of the vessel was impossible because of the overlying hard mass. To avoid a permanent occlusion, we decided to coat the injured artery wall with 100% NBCA. For this, 0.5 ml of NBCA was distributed on the surface of the injured segment and surrounding subarachnoid space by injection through a needle. An excellent hemostasis could be obtained immediately after coating. The patient woke up with no new neurological deficits. A digital cerebral angiogram obtained a few days after the procedure did not show vasospasm, stenosis, or pseudoaneurysm in the supraclinoidal segment of the carotid artery. A magnetic resonance angiogram obtained 3 years later showed a normal shape of the internal carotid artery and a stable residual tumor without inflammatory signs. The child is now attending school and is under hormonal therapy. CONCLUSION: For hemostatic purposes, the technique of coating an injured arterial wall with NBCA may be useful in cases in which a microsuture is impossible and a permanent artery occlusion is unwanted because of a risk of an ischemic stroke. It could serve as a transitory measure until a microsurgical bypass or the balloon test occlusion tolerance allow the trapping of the affected artery.

Brain Neoplasms↗

PubMed2005

The brain tumor board: lessons to be learned from an interdisciplinary conference.

BACKGROUND: The aim of this study is to analyze the work of the interdisciplinary Brain Tumor Board (BTB) which was established at Freiburg University Hospital in 1998. PATIENTS AND METHODS: From January 1998 to December 2003, a total of 1,516 patients were discussed in 259 meetings of the BTB. The protocols of the BTB were analyzed retrospectively. RESULTS: In 79% of the patients, the diagnosis was based on histological findings or a typical radiological appearance of a lesion, or both. This group was composed of 4 subgroups: 28% benign skull base tumors (19% meningiomas, 4% pituitary adenomas, 3% acoustic schwannomas, 2% others), 24% primary brain tumors of glial origin (8% glioblastomas, 12% gliomas other than glioblastomas, 5% oligoastrocytomas or oligodendrogliomas), 19% brain metastases, and 8% other brain or skull base tumors. In 13% of the cases, the exact diagnosis was still unknown when the patient was presented. 8% of the presentations were motivated by nontumorous interdisciplinary problems (e.g. arterio-venous malformations). The recommendations given by the BTB included: 23% further diagnostic procedures (11% non-invasive examinations, 12% stereotactic biopsies), 57% active antitumoral therapy (22% resection, 17% fractionated radiotherapy, 13% radiosurgery, 5% chemotherapy, <1% embolization), 20% no treatment (14% watchful waiting, 6% supportive care). 91% of the BTB recommendations were realized within 3 months. CONCLUSION: Interdisciplinary care seems to be particularly necessary in patients with benign skull base tumors, gliomas and brain metastases. Decisions made in a small interdisciplinary group of experts have a high potential of subsequently being realized.

Academic Medical Centers↗

PubMed2004

Neuronavigation-assisted cranial reconstruction.

OBJECTIVE: Cranial defects resulting from congenital deformities, ablative resection of osseous tumors, traumatic injury, and destructive infectious lesions are often severe enough to warrant surgical reconstruction. In particular cases, satisfactory cosmetic results may be difficult to achieve because of the extent and location of the lesion. METHODS: We evaluated the role of neuronavigation for reconstruction of large cranial defects with prefabricated titanium and intraoperatively constructed neuronavigation-assisted polymethylmethacrylate implants. RESULTS: Neuronavigation-assisted cranial reconstruction was performed in 14 patients. Surgical procedure, illustrative cases, postoperative results, and apparent benefits of the technique are presented and discussed. In all patients, excellent cosmetic results were achieved. CONCLUSION: In cranial reconstruction, neuronavigation is of value not only for intraoperative determination of resection margins but also for preoperative assessment and planning. The combination of navigation techniques with prefabricated or intraoperatively constructed implants enables achievement of excellent cosmetic results.

Adult↗

PubMed2004

Development of a complex dural arteriovenous fistula next to a cerebellar developmental venous anomaly after resection of a brainstem cavernoma. Case report and review of the literature.

Developmental venous anomalies (DVAs) are common abnormalities of intracranial venous drainage, which may occur in conjunction with other cerebral vascular malformations and are known for their benign natural history. The authors present the case of a 16-year-old boy who experienced a spontaneous brainstem hemorrhage due to a cavernoma. Preoperative angiography findings revealed a large DVA draining the right cerebellar hemisphere. The patient underwent suboccipital surgery for cavernoma resection and recovered completely from his neurological symptoms. Fourteen months later he returned with progressive symptoms. Repeated angiography demonstrated a complex dural arteriovenous fistula (DAVF) of the transverse sinus, which had developed next to the DVA. Several transarterial and transvenous embolizations were ineffective. Common causes of acquired DAVFs and the potential role of the DVA in the development of the DAVF in this case are discussed on the basis of the pertinent literature.

Acetazolamide↗

PubMed2003

Quantitative measurement of depolarization-induced anandamide release in human and rat neocortex.

It has been suggested that the endocannabinoid anandamide is released from central neurons upon depolarization of the cell membrane. In order to determine whether anandamide levels were increased after K(+) depolarization of fresh human and rat brain slices, we developed a rapid and sensitive method for the isolation and quantitation of anandamide. This included solvent extraction, solid phase separation, and reversed phase high performance liquid chromatography (HPLC) with fluorometric detection. Compared with basal levels, K(+) stimulation enhanced the neocortical anandamide concentration in both species (70.5 vs. 21.1 pmol/g tissue in humans, 14.3 vs. 3.2 pmol/g tissue in rats). Basal anandamide levels in the rat hippocampus (11.1 pmol/g) were significantly higher than in the neocortex. Anandamide was also detected in the human amygdala (67.8 pmol/g). In conclusion, our data provide evidence for the depolarization-induced synthesis of anandamide, supporting the hypothesis of a neuromodulatory action of this endocannabinoid. Furthermore, the presence of anandamide in the limbic system suggests participation in cognition, behavior or reward.

Amygdala↗

PubMed2003

Perspectives and limitations of image-guided neurosurgery in pediatric patients.

INTRODUCTION: Progress in image-guided neurosurgery, and specifically in computer-assisted frameless navigation techniques and the application of robotic systems, has brought about many changes in the way we approach and treat pathologies involving the adult and pediatric central nervous system (CNS). Nevertheless, children are a patient group with special demands, in whom image-guided surgical techniques have certain limitations. In this article we address the common problem of registration accuracy in image-guided neurosurgery and assess both the reliability and the potential of ultrasound-based neuronavigation and robot-assisted neuroendoscopy in pediatric patients. METHODS AND RESULTS: We present our experience with new referencing and tracking techniques adapted to the needs of the pediatric patient. In addition, advantages and limitations of a 3D real-time ultasonography-based navigation system are demonstrated. Finally, we describe our experience with robot-assisted neuroendocopy and discuss the possible implications of the technique for the future. CONCLUSION: Image-guided techniques in pediatric neurosurgery are valuable tools and may open up new perspectives in the future. From our point of view, these tools enhance both intellectual and manual surgical skills, which does not mean that they should be considered as a replacement for such skills.

Adolescent↗

PubMed2003

Implications of vascular endothelial growth factor, sFlt-1, and sTie-2 in plasma, serum and cerebrospinal fluid during cerebral ischemia in man.

The relation between cerebral ischemia and local release of angiogenic factors was investigated after subarachnoid hemorrhage (SAH) in humans. Time-dependent concentration-changes of vascular endothelial growth factor (VEGF), sFlt-1 and sTie-2 extracted from plasma, serum, and cerebrospinal fluid (ventricular, cisternal, and lumbar) were analyzed in 15 patients surgically treated for ruptured aneurysms of the anterior circulation (Hunt and Hess grades I-V). Data were related to brain Po2 (Pbro2) and cerebral energy metabolites (extracellular lactate, pyruvate, glutamate, and glycerin concentrations) as well as clinical and radiologic reference data. Delayed impairment of cerebral perfusion secondary to progressive microcirculatory alterations was associated with reduced local Pbro2 and energy metabolism (increased lactate-pyruvate ratio, glutamate and glycerine levels). Elevated serum/plasma and CSF concentrations of VEGF, sFlt-1, and sTie-2 matched the scale of ischemic tissue hypoxia. Excessive VEGF/sFlt-1 and sTie-2 levels were related to Pbro2 values consistently less than 5 mm Hg, glutamate concentrations greater than 300 micromol/L, lactate-pyruvate ratio greater than 300, cerebral infarction, and reduced outcome (P < 0.01). Delayed microcirculatory impairment was mirrored by distinct elevation of cisternal and arterial VEGF and sFlt-1 concentrations, suggesting local induction of angiogenesis. Arterial levels of VEGF, sFlt-1, and sTie-2 reflect both extent and time course of compensatory, yet clinically inefficient, angiogenesis in the absence of general hypoxia.

Adult↗