Showing papers by "Alexander Brawanski published in 2005"
TL;DR: The results demonstrate that CA IX and XII are upregulated in intrinsic and metastatic brain tumors as compared to normal brain tissue, which may contribute to the management of tumor-specific acid load and provide a therapeutic target.
Abstract: Malignant brain tumors exhibit distinct metabolic characteristics. Despite high levels of lactate, the intracellular pH of brain tumors is more alkaline than normal brain. Additionally, with increasing malignancy, brain tumors display intratumoral hypoxia. Carbonic anhydrase (CA) IX and XII are transmembrane isoenzymes that are induced by tissue hypoxia. They participate in regulation of pH homeostasis by catalyzing the reversible hydration of carbon dioxide. The aim of our study was to investigate whether brain tumors of different histology and grade of malignancy express elevated levels of CA IX and XII as compared to normal brain. We analyzed 120 tissue specimens from brain tumors (primary and metastatic) and normal brain for CA IX and XII expression by immunohistochemistry, Western blot, and in situ hybridization. Whereas normal brain tissue showed minimal levels of CA IX and XII expression, expression in tumors was found to be upregulated with increased level of malignancy. Hemangioblastomas, from patients with von Hippel-Lindau disease, also displayed high levels of CA IX and XII expression. Comparison of CA IX and XII staining with HIF-1alpha staining revealed a similar microanatomical distribution, indicating hypoxia as a major, but not the only, induction factor. The extent of CA IX and XII staining correlated with cell proliferation, as indicated by Ki67 labeling. The results demonstrate that CA IX and XII are upregulated in intrinsic and metastatic brain tumors as compared to normal brain tissue. This may contribute to the management of tumor-specific acid load and provide a therapeutic target.
91 citations
TL;DR: Because of high complication rates and poor results it is concluded that sural nerve biopsy should be done only in carefully selected cases after thorough clinical work-up, and should be limited to cases of suspected inflammatory neuropathies, collagenoses and immunologic neuro Pathies, and hereditary Neuropathies.
48 citations
TL;DR: Despite the limitations concerning image distortions and slice thickness, direct target planning on MRI, regarding the results, is more reliable than targeting solely based on atlas derived data.
Abstract: Background. In deep brain stimulation the way to define and localize the optimal target for the individual patient is still under debate. The objective of our study was to investigate the reliability of atlas derived data by comparing them with direct targeting on MR images.
45 citations
TL;DR: An approximately linear correlation of the partial oxygen pressure of brain tissue to the mean arterial blood pressure in the case of an impaired autoregulation mechanism is found.
Abstract: A compartment model of cerebral circulation and oxygen supply including an autoregulation mechanism is presented. The model is focused on the analysis of slow dynamical variations of long term neurophysiological parameters like the partial oxygen pressure of brain tissue or the cerebral blood flow. The circulatory part of the model is built up of seven compartments including arteries, capillaries, veins, brain tissue, cerebrospinal fluid, the sagittal sinus and an artificial compartment for the simulation of brain swelling. The description of oxygen supply is based on a Krogh model. Numerical calculations reproduce the experimentally well established connection between arterial blood pressure and the production of cerebrospinal fluid. Furthermore we found an approximately linear correlation of the partial oxygen pressure of brain tissue to the mean arterial blood pressure in the case of an impaired autoregulation mechanism. In a first test such a linear dependence could also be detected in clinical data from the neurosurgical intensive care monitoring.
36 citations
TL;DR: The case of a 29-year-old previously healthy man who presented with L-5 radiculopathy, who had a large gout tophus mimicking a malignant spinal tumor or abscess, and the case history, intraoperative, MR imaging, and histological findings are described.
Abstract: ✓ Symptomatic gout tophi of the spine are a rare but well-characterized complication of tophaceous gout. The authors report the case of a 29-year-old previously healthy man who presented with L-5 radiculopathy. Lumbar magnetic resonance (MR) imaging revealed a 4.5 × 4.5 × 2.8—cm large gout tophus mimicking a malignant spinal tumor or abscess. The tophus completely destroyed both L-4 and L-5 facet joints and the left L-4 lamina and spread epidurally from L-3 to L-5, compressing the left L-5 nerve root. There has been no similar case reported so far with respect to the extent of bone destruction. The authors describe the case history and present intraoperative, MR imaging, and histological findings.
35 citations
TL;DR: The Quantix ND seems a valuable tool in diagnosing cerebral hyperemia in arteriovenous malformations where cerebral blood flow is known to be increased.
Abstract: Angle-independent ultrasound assessment of the volume flow in the extracranial internal carotid artery (ICA) is a new approach to evaluate the perfusion status of the human brain. Normal values using a new technical device (Quantix ND, Cardiosonix Ltd, Israel) and correlation analysis to quantitative CBF measurements were recently published. Aim of this study was to evaluate this device in arteriovenous malformations where cerebral blood flow is known to be increased. Five patients suffering from large supratentorial arteriovenous malformations (AVM) could be examined. All patients showed pre-operatively elevated flow volumes in the internal carotid artery on the side harbouring the pathological lesion compared with normal values evaluated in 50 volunteers. The contralateral internal carotid artery showed volume flow values within the normal limit. After surgical resection of the malformation normal values could be measured in all patients. Pathological elevated increases in cerebral blood flow can be evaluated by ultrasonic blood flow volume assessment in the extracranial internal carotid artery. Therefore, the Quantix ND seems a valuable tool in diagnosing cerebral hyperemia.
7 citations