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Biomedical subjects

E R Gizewski

Publications and source records attributed to E R Gizewski.

14 recordsLinked to original sources
PubMed2006

Activation of cerebellar nuclei comparing finger, foot and tongue movements as revealed by fMRI.

The aim of the present study was to compare possible activation of the interposed and dentate cerebellar nuclei during finger, foot and tongue movements using functional magnetic resonance imaging (fMRI). Nineteen healthy control subjects performed sequential finger and repetitive tongue and foot movement tasks. Thin slices (2.5mm) were acquired of the cerebellar region containing the cerebellar nuclei with high spatial resolution (matrix size 128 x 128 x 10) using a Siemens 1.5T Sonata system. Use of an eight channel head coil provided better signal-to-noise-ratio compared to standard head coils. Only data of those 12 subjects were included in final statistical analysis, who showed significant activation of the cerebellar nuclei at least in one task. Cortical activations of the superior cerebellum were found in accordance to the known somatotopy of the human cerebellar cortex. Nuclear activations were most significant in the sequential finger movement task. Both interposed nuclei and ipsilateral dentate nucleus were activated. Dentate activation was present in the more caudal parts of both the dorsal and ventral nucleus. Activation overlapped with motor and non-motor domains of the dentate nucleus described by Dum and Strick [R.P. Dum, P.L. Strick, An unfolded map of the cerebellar dentate nucleus and its projections to the cerebral cortex, J. Neurophysiol. 89 (2003) 634-639] based on anatomical data in monkey. Tongue movement related activations were less extensive and overlapped with activations of caudal parts of the dentate nucleus in the finger movement task. No nuclear activation was seen following foot movements. The present findings show that both interposed and dentate nuclei are involved in sequential finger movements in humans. Interposed nucleus likely contributes to movement performance. Although no direct conclusions could be drawn based on the present data, different parts of the dentate nucleus may contribute to movement performance, planning and possible non-motor parts of the task.

Adult↗
PubMed2006

Verb generation in children and adolescents with acute cerebellar lesions.

The aim of the present study was to examine verb generation in a larger group of children and adolescents with acute focal lesions of the cerebellum. Nine children and adolescents with cerebellar tumours participated. Subjects were tested a few days after tumour surgery. For comparison, a subgroup was tested also 1 or 2 days before surgery. None of the children had received radiation or chemotherapy at or before the time of testing. Eleven age- and education-matched control subjects participated. Subjects had to generate verbs to blocked presentations of photographs of objects. As control condition, the objects had to be named. Furthermore, dysarthria was quantified by means of a sentence production and syllable repetition task. Detailed analysis of individual 3D-MR images revealed that lesions affected cerebellar hemispheres in all children and adolescents. The right cerebellar hemisphere was affected in four and the left hemisphere in five subjects. In the present study, naming and verb generation accuracy were preserved in the majority of subjects with cerebellar lesions. No significant signs of learning deficits were observed, as reduction of reaction times over blocks was not different compared to controls. There was a trend of children and adolescents with right-hemispheric lesions to perform worse compared to controls. In this group, however, significant signs of dysarthria were present. In sum, no significant signs of disordered verb generation were observed in children and adolescents with acute cerebellar lesions. Findings suggest that the role of the cerebellum in verb generation may be less pronounced than previously suggested. Findings need to be confirmed in a larger group of subjects with acute focal lesions.

Acute Disease↗
PubMed2006

Endovascular treatment of middle cerebral artery aneurysms with electrolytically detachable coils.

BACKGROUND AND PURPOSE: Middle cerebral artery (MCA) aneurysms often have an unfavorable aneurysm geometry that might limit endovascular therapy. Our purpose was to analyze the feasibility, safety, and efficacy of coil embolization in a consecutive series of MCA aneurysms chosen for endovascular treatment. PATIENTS AND TECHNIQUES: Of 235 MCA aneurysms seen at our institution during the past 5 years, 36 patients harboring 38 MCA aneurysms were primarily selected for coil embolization: 18 patients had an acute subarachnoid hemorrhage (SAH), 16 of which were due to a ruptured MCA aneurysm. SAH was classified according to Hunt and Hess grade: I (5), II (7), III (5), IV (0), and V (1). RESULTS: Complete occlusion could be achieved in 33 of 38 aneurysms. In 5 aneurysms, coil embolization was not performed because of an unfavorable aneurysm geometry with a wide neck or incorporation of adjacent branches (3) or failed because of insecure coil placement (1) or severe vasospasm (1). Procedural complications included coil protrusion into the parent artery (1), and thromboembolic M2 occlusion (5), with recanalization in 4 of 5 cases. Of 8 aneurysms with initial subtotal occlusion, 3 progressed to total occlusion during follow-up. Three aneurysms had to be retreated, and no patient rebled. Glasgow Outcome Scale at 6 months for the patients with SAH (17/18) was good recovery (12), moderate disability (4), severe disability (0), persistent vegetative state (0), and death (1); outcomes for patients with an incidental aneurysm (17/18) were good recovery (16) and moderate disability (1). CONCLUSION: Endovascular coil embolization can be performed safely and effectively in selected MCA aneurysms. Initial subtotal aneurysm occlusion might progress to total occlusion.

Adult↗
PubMed2005

Trace eyeblink conditioning in human subjects with cerebellar lesions.

Trace eyeblink conditioning was investigated in 31 patients with focal cerebellar lesions and 19 age-matched controls. Twelve patients presented with lesions including the territory of the superior cerebellar artery (SCA). In 19 patients lesions were restricted to the territory of the posterior inferior cerebellar artery (PICA). A 3D magnetic resonance imaging was used to determine the extent of the cortical lesion and possible involvement of cerebellar nuclei. Eyeblink conditioning was performed using a 40 ms tone as conditioned stimulus (CS) followed by a stimulus free trace-interval of 400 ms and a 100 ms air-puff as unconditioned stimulus (US). In SCA patients with lesions including parts of the cerebellar interposed nucleus trace eyeblink conditioning was significantly impaired. Pure cortical lesions of the superior cerebellum were not sufficient to reduce acquisition of trace conditioned eyeblink responses. PICA patients were not impaired in trace eyeblink conditioning. Consistent with animal studies the findings of the present human lesion study suggest that, in addition to forebrain areas, the interposed nucleus is of importance in trace eyeblink conditioning. Although cortical cerebellar areas appear less important in trace compared with delay eyeblink conditioning, the present data strengthen the view that cerebellar structures contribute to different forms of eyeblink conditioning paradigms.

Adult↗
PubMed2005

Functional localization in the human cerebellum based on voxelwise statistical analysis: a study of 90 patients.

The aim of the present study was to examine somatotopy in the cerebellar cortex and a possible differential role of the cerebellar cortex and nuclei in functional outcome. Clinical findings and 3D MRI-based cerebellar lesions site were compared in a group of 90 patients with focal cerebellar lesion using International Cooperative Ataxia Rating Scale (ICARS) and voxel-based lesion-symptom mapping (VLSM). Separate analysis was performed in patients with acute and chronic ischemic lesions (n=43) and patients with acute and chronic surgical lesions (n=47). Thirty-eight patients were included after resection of a cerebellar tumor in childhood or adolescence. The most significant lesion symptom correlations were observed in the subgroup with acute ischemic lesions. Limb ataxia was significantly correlated with lesions of the interposed (NI) and part of the dentate nuclei (ND), ataxia of posture and gait with lesions of the fastigial nuclei (NF) including NI. Correlations with cortical lesions were less significant and present in the superior cerebellum only. Upper limb ataxia was correlated with lesions of vermal, paravermal and hemispheral lobules IV-V and VI, lower limb ataxia with lesions of vermal, paravermal and hemispheral lobules III and VI, dysarthria with lesions of paravermal and hemispheral lobules V and VI and ataxia of posture and gait with lesions of vermal and paravermal lobules II, III and IV. In the subgroups with chronic focal lesions, similar correlations were observed with lesions of the cerebellar nuclei, but significantly less correlations with lesions of the cerebellar cortex. Functional localization based on VLSM backs findings in previous animal and functional brain images studies in healthy human subjects. The lesion site appears to be critical for motor recovery. Lesions affecting the cerebellar nuclei are not fully compensated at any age and independent of the pathology in humans.

Adult↗
PubMed2005

Treatment of wide-necked intracranial aneurysms with a self-expanding stent: mid-term results.

PURPOSE: To evaluate mid-term clinical and angiographic results after using a self-expanding neurovascular stent and coils for the management of broad-based intracranial aneurysms. METHODS: During the period from August 2001 to October 2004 we treated a total of 42 patients with 44 aneurysms using a self-expandable stent. To date we have data on more than 6 months of follow-up in 25 patients with 26 aneurysms. Aneurysm occlusion was divided into the following categories: 100 % (complete), 95-99 % (subtotal), and < 95 % (incomplete). RESULTS: In 15 aneurysms complete occlusion, in 11 aneurysms subtotal occlusion was initially achieved. Control DSA showed progressive thrombosis in seven aneurysms leading to total occlusion in another 4 aneurysms. Three recanalizations were observed in one large and two giant ICA aneurysms. No vessel occlusion occurred. One vessel stenosis of the stented segment was noted, but it was not clinically relevant. One patient experienced a small embolic infarction after stopping antiplatelet medication. No persistent deterioration of the clinical status occurred. CONCLUSION: Combining a stent with coils seems to be an acceptable treatment option for broad-based intracranial aneurysms. As this special subgroup of treated aneurysms includes only those with an unfavourable geometry, the results are extremely promising.

Aneurysm, Ruptured↗
PubMed2003

Cross-modal plasticity for sensory and motor activation patterns in blind subjects.

Experimental data on cortical reorganization in blind subjects using H(2)(15)O positron emission tomography and functional magnetic resonance imaging (fMRI) showed activation of the visual cortex related to Braille reading and tactile discrimination tasks in congenitally and early blind subjects. The purpose of our study was to differentiate whether occipital activation of blind subjects during Braille reading is task specific or only triggered by sensory or motor area activation. Twelve congenitally and early-onset blind subjects were studied with fMRI during Braille reading, discriminating nonsense dots, sensory stimulation with electromagnetic pulses, and finger tapping. All experiments were performed utilizing a block design with 6 active epochs alternating with 6 rest conditions lasting 34 s each. Echo-planar imaging sequences with 34 transversal slices were performed on a 1.5-T MR scanner. All blind individuals reading Braille and discriminating nonsense dots showed robust activation of the primary, secondary, and higher visual cortex. Application of peripheral electrical stimuli to the reading hand revealed expected sensory activation of the primary somatosensory cortex, but no activation in the visual cortex. Pure motor activation during finger tapping with the reading hand showed expected precentral activation and no activation of visual cortex. In conclusion, occipital activation during Braille reading and discrimination tasks is not due to plasticity of sensory or motor function; pure motor or sensory tasks do not lead to an activation of striate cortex. The brain learns to differentiate between "finger touching" and "finger reading." Our results suggest that activation of the visual cortex in blind subjects is related to higher and more complex brain functions.

Adult↗
PubMed2001

Histiocytosis mimicking a pineal gland tumour.

We report an unusual case of isolated Langerhans cell histiocytosis of the central nervous system. A 19-year-old man presented with an incomplete ocular palsy. MRI revealed a solitary mass in the pineal gland with marked contrast enhancement. Complete microsurgical excision was followed by local radiotherapy. Histological examination revealed histiocytosis. Unifocal brain involvement by histiocytosis X is rare with few cases in the literature; the most commonly involved areas are the hypothalamus and the pituitary gland.

Brain Neoplasms↗
PubMed1997

Rapid decrease in cellular sodium and chloride content during cold incubation of cultured liver endothelial cells and hepatocytes.

Hypothermia, as used for organ preservation in transplantation medicine, is generally supposed to lead to an intracellular accumulation of sodium, and subsequently of chloride, via inhibition of the Na+/K+-ATPase. However, on studying the cellular sodium concentration of cultured liver endothelial cells using fluorescence microscopy, we found a 55% decrease in the cellular sodium concentration after 30 min of cold incubation in University of Wisconsin (UW) solution. To confirm this surprising result, we set up a capillary electrophoresis method that allowed us to determine the cellular contents of inorganic cations and of inorganic anions. Using this method we measured a decrease in the cellular sodium content from 104+/-11 to 55+/-4 nmol/mg of protein, accompanied by a decrease in the chloride content from 71+/-9 to 25+/-5 nmol/mg of protein, after 30 min of cold incubation in UW solution. When the endothelial cells were incubated in cold Krebs-Henseleit buffer or in cold cell culture medium instead of UW solution, similar early decreases in cellular sodium and chloride contents were observed, thus excluding the possibility of the decreases being dependent on the preservation solution used. Furthermore, experiments with cultured rat hepatocytes yielded a similar decrease in sodium content during initiation of cold incubation in UW solution, so the decrease does not appear to be cell-specific either. These results suggest that, contrary to current opinion, sodium efflux predominates over sodium influx during the early phase of cold incubation of cells.

Adenosine↗
PubMed1997

Involvement of reactive oxygen species in the preservation injury to cultured liver endothelial cells.

We have previously demonstrated an energy-dependent injury to cultured liver endothelial cells during cold incubation in University of Wisconsin (UW) solution. In the present study, we report experimental evidence for the involvement of reactive oxygen species in this injury: LDH release during 48 h of cold incubation in UW solution was decreased from 40-55% under aerobic conditions to less than 20% under hypoxic conditions or by the presence of KCN (1 mM). Similar protection was achieved by the addition of the spin trap 5,5-dimethyl-1-pyrroline N-oxide, the hydroxyl radical scavenger dimethyl sulfoxide, or the flavonoid silibinin to UW solution under aerobic conditions. Preincubating the cells with the iron chelator deferoxamine even decreased the injury to less than 5%. The residual injury (as observed after longer incubation times) under hypoxic conditions or in cells preincubated with deferoxamine was no longer energy dependent. The amount of thiobarbituric acid-reactive substances markedly increased during cold incubation of the cells in UW solution. This increase was not observed in UW solution to which KCN had been added, i.e., under the conditions of energy depletion. These results suggest that an iron-dependent generation of reactive oxygen species with subsequent lipid peroxidation is involved in the pathogenesis of the injury to cultured liver endothelial cells in cold UW solution.

Animals↗
PubMedDate not supplied

Recurrent neurovascular hypertension: MR findings before and after surgical treatments.

A case of recurrent brain stem edema after surgical vascular decompression in a patient with neurogenic hypertension is presented. The surgical treatment resulted in occlusion of the left vertebral artery, stable blood pressure values, and no recurrence of the brain stem edema. MR imaging and MR angiography are excellent methods with which to assess patients suspected of having neurovascular hypertension, both before and after surgical treatment.

Adult↗
PubMedDate not supplied

Cavernous malformation with hemorrhage of the conus medullaris and progressive sensory loss.

Numerous studies have shown that cavernous malformations may be localized in almost every region of the brain as well as in the spinal cord. Spinal cord cavernous malformations (SCCM) have been diagnosed more frequently since magnetic resonance imaging (MRI) has become more widely available. Most are asymptomatic but may present as a diagnostic challenge with diffuse symptoms ranging from mere sensory deficits to paraparesis possibly affecting both upper and lower motor neuron. A 29-year-old Arabian man was admitted to the hospital with a progressive sensory loss to light touch, pin prick and vibration of the right and in a lesser extent of the left leg without any association to a particular dermatome. He additionally presented with progressing paresthesias in both legs, unsteady gait and incipient bladder- and bowl incontinence starting approximately 1 week prior to admission. Spinal MRI showed a central, slightly lateralized intramedullary lesion 1 cm in diameter located within the conus medullaris that was suspicious for an intramedullary cavernous malformation. The lesion was accompanied by a perifocal edema and showed an inhomogeneous hypointense core on T2WI consistent with an acute cavernous hemorrhage. Treatment of symptomatic intramedullary cavernous angiomas should, if possible, consist of total surgical excision. It is essential to achieve complete removal during the first operation to avoid any residues that may lead to further bleeding.

Adult↗