Unilateral adult malignant glioma of the optic nerve is exceptional. The final diagnosis was only confirmed by optic nerve biopsy. In the literature, only one patient has been reported with a unilateral tumour manifestation; he was lost to follow-up 3 months later. All other cases were bilateral. To date, 44 case reports of adult malignant optic nerve glioma have been published, either malignant astrocytoma or glioblastoma. These tumours can mimic optic neuritis in their initial presentation. The diagnosis is seldom made before craniotomy. On MRI images, malignant glioma cannot be distinguished from optic nerve enlargement due to other causes. Although radiotherapy appears to prolong life expectancy, all presently available treatment options (radiation, surgery, radio-chemotherapy) are of limited value. Most patients go blind and die within 1 or 2 years.
Poly‐Lactic‐Acid (PLA) was evaluated for coating of vascular endoprostheses in the treatment of experimental arterio‐venous‐fistulae (AVF). Bilateral carotid – external jugular AVF were created in 5 adult dogs. 7 PLA coated nitinol stents were placed via a transfemoral approach covering 5 AVF. The contralateral AVF remained untreated. Angiography was performed immediately after stent placement, at weeks 1 and 3 and at months 3, 6 and 9. All grafts were removed and underwent histologic examination. In 2 cases the occlusion of the AVF was successful, while misplacement occurred in 3 cases. Occlusion of the parent vessel was disclosed in 3 cases. Histologic examination revealed a mild inflammatory reaction with the presence of macrophages. There was no foreign‐body reaction or fragmentation of the arterial vessel wall. PLA, which is a well‐known biodegradable material, showed a good mid‐term biocompatibility. Elastic mismatch of the non‐elastic coating and the self‐expandable nitinol stent caused misplacement. Frequent vessel‐occlusions were probably due to PLA‐filaments fraying into the vessel lumen. Using a different textile structure PLA might be a material suitable for coating endovascular stents.
Objective: Ablative tumor surgery requires detailed planning using computed tomography (CT) or magnetic resonance imaging (MRI). Reconstruction following tumor resection is dependent on reliable information for choosing the correct type and volume of grafts and predicting the outcome. This study evaluates the benefit of and the indications for computer-assisted surgery in the treatment of cranio-maxillofacial tumors.Materials and Methods: Based on a CT or MRI data set, the STN Navigation System (Stryker-Leibinger) was used for preoperative planning, intraoperative navigation, and postoperative control of radical tumor resection and primary and secondary reconstruction. Tumor resection was preoperatively planned and intraoperatively navigated. Preoperatively, the required soft and hard tissue were measured using the mirrored data set of the unaffected side of the facial skeleton; the size and location of the graft were chosen virtually. Intraoperatively, contours of transplanted tissues were navigated in accordance with the preoperatively simulated reconstructive result.Results: Computer-assisted treatment was successfully completed in all cases of radical tumor resection, and safety margins outlined preoperatively could be precisely controlled during tumor resection. Reconstruction was designed and performed exactly as virtually planned.Conclusions: Image-guided treatment improves preoperative planning by visualization of the individual anatomy and the intended reconstructive outcome, and by objectivation of the effect of adjuvant chemo-/radiotherapy. Intraoperative navigation makes radical tumor surgery more reliable by showing the determined safety margins, preserving vital structures, and guiding reconstruction to preplanned objectives. OBJECTIVEComputer-assisted technology was initially developed to provide neurosurgeons with precise guidance during surgical procedures. Currently available systems with and without robotic navigation are in use for specific medical indications. Various intraoperative navigation systems are used to assist
We report an intramedullary angiolipoma with spinal cord compression studied by MRI, angiography and CT. Angiolipomas of the spine are rare benign tumours containing vascular and mature adipose elements. They are epidural in more than 90 % of the cases; only three cases of intramedullary angiolipoma are described. The clinical picture is nonspecific, but MRI and CT suggest the diagnosis.
In order to assess the autoinhibitory control of endogenous acetylcholine (ACh) in rat and human neocortex, slices of these tissues were prelabelled with [(3)H]choline, superfused continuously and stimulated electrically using various frequencies in the presence or absence of drugs. The autoinhibitory feedback control of [(3)H]ACh release was operative - despite the absence of blockers of ACh esterase - at stimulation frequencies >/= 3 Hz in rat and >/= 6 Hz in human neocortex tissue. At these frequencies the muscarinic antagonist atropine (0.1 microM) disinhibited the release of [(3)H]ACh in both species. Estimation of the biophase concentration of ACh near the autoreceptor in the rat neocortex from concentration-response curves of the muscarinic agonist oxotremorine revealed that at 3 Hz about 25% of the autoreceptors were activated by endogenously released ACh. This estimation is consistent with an increase in [(3)H]ACh release to about 120% of control values by complete blockade of autoreceptors with atropine. The observation that in human neocortical tissue presynaptic autoinhibition of [(3)H]ACh release is operative at stimulation frequencies >/= 6 Hz suggests that selective blockade of autoinhibition may also increase ACh release in the cortex of Alzheimer's disease patients, without additional blockade of the enzyme acetylcholinesterase.
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