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R Schober

Publications and source records attributed to R Schober.

At least 19 recordsLinked to original sources
PubMed2006

Surgery of cavernous malformations with and without navigational support--a comparative study.

BACKGROUND: The aim of this descriptive study was the comparison of the clinical and surgical data of patients who suffered from cavernoma and were treated surgically with and without intraoperative navigation (ultrasound, neuronavigation). METHOD: Between 1995 and 2002, 40 patients were treated for cavernous malformations microsurgically: 24 patients (group I) using a neuronavigation system (STP 4.0, SNN, Germany), 7 patients (group II) using ultrasound (Siemens Omnia with 5.0 MHz Probe) and 9 patients (group III) without any image guidance using anatomic landmarks. FINDINGS: With the use of neuronavigation the mean sizes of cavernous malformations, which were resected, were reduced from 25.6 mm (group III) and 24.4 mm (group II) to 16.3 mm (group I) (p > or = 0.05). Corresponding to the reduction of the cavernoma size, the mean distances of the vascular lesion to the cortical surface increased from 13.9 mm (group III) and 17.8 mm (group II) to 24.4 mm under neuronavigational support (p > or = 0.05). All cavernomas were resected completely in all 40 patients. Postoperative neuroradiological control (MRI) confirmed complete resection in all cases. No significant differences in the clinical outcome could be evaluated in all three groups up to three months postoperatively. CONCLUSIONS: Use of neuronavigation was associated with a more comfortable and safer surgery of smaller and more deeper-seated cavernomas. In spite of the lack of significance between all groups, the advantages of neuronavigation in planning and realising surgery could be documented, which justify the additional costs and time-consuming acquisition of planning image data and postprocessing as well as intraoperative navigation.

Adolescent↗
PubMed2005

[Facioscapulohumeral muscle dystrophy and heart disease].

Cardiac involvement is well known in a number of skeletomuscular diseases but not in facio-scapulohumeral muscular dystrophy (FSHD). We report on a 71 year old woman with progressive cardiac insufficiency in FSHD, which was also confirmed by molecular analysis in one of the two daughters affected by the disease. Autopsy of the deceased patient showed the typical changes in skeletal muscles including focal inflammatory infiltrates in the diaphragm and, in addition, cardiac muscular involvement. The histological changes resembled those seen in primary cardiomyopathy despite the normal muscle mass volume. Both clinically and morphologically, the cardiac disease was the cause of death in this patient with FSHD.

Aged↗
PubMed2005

Genetic-morphologic association study: association between the low density lipoprotein-receptor related protein (LRP) and cerebral amyloid angiopathy.

Accumulating evidence suggests that genetic factors such as apolipoprotein E (APOE), can act in different ways in the pathogenesis of cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD). The role of the low-density lipoprotein-receptor related protein (LRP), the major cerebral APOE receptor, in AD has been discussed controversially depending on data from different populations and methodological approaches. We examined the influence of LRP polymorphisms on CAA in 125 post-mortem cases genotyped for APOE and classified according to the neurofibrillary Braak and Braak staging of AD (indicating neurodegeneration grade). CAA was assessed separately for leptomeningeal (CAAlep.), noncapillary cortical (CAAcort.) and capillary cortical (CAAcap.) vessels in beta-amyloid stained sections. Our results suggest: (i) the 87 bp allele of LRP5' polymorphism (LRP5') is an independent predictive factor for CAAcort. and CAAlep.; (ii) the C/C genotype (C allele) of the LRP exon 3 polymorphism is positively associated with the severity of CAAlep. and CAAcort., implicating a younger age of CAA onset and/or faster CAA progression; (iii) as CAAcort. and CAAlep. showed different genetic associations in contrast to CAAcap., we can underscore the hypothesis that different molecular mechanisms are involved in CAA pathogenesis of noncapillary and capillary cerebral vessels. Our results lead us to postulate that the LRP5'87 bp and the LRP exon 3 C alleles of the LRP gene (or another locus that might be in linkage disequilibrium with these LRP polymorphic sites) could modify cerebrovascular LRP function or expression in noncapillary cerebral vessels, leading to an increased cerebrovascular amyloid deposition.

Aged↗
PubMed2004

Laser-induced thermotherapy of neoplastic lesions in the brain--underlying tissue alterations, MRI-monitoring and clinical applicability.

Laser-induced thermotherapy (LITT) is a minimally invasive neurosurgical approach to the stereotactic treatment of brain tumors in poorly accessible regions. Its clinical applicability has been shown in several experimental and clinical studies under on-line monitoring by magnetic resonance imaging (MRI). This review characterizes LITT as an alternative neurosurgical approach with specific focus on the typical histological alterations and ultrastructural cellular changes following laser irradiation in the central nervous system. The spatial and temporal pattern of these changes is discussed in their relevance to the neurosurgical treatment of neoplastic lesions using LITT.

Aged↗
PubMed2004

Continuous measurements of cerebral tissue oxygen pressure during hyperbaric oxygenation--HBO effects on brain edema and necrosis after severe brain trauma in rabbits.

INTRODUCTION: Severe brain injury is one of the most frequent causes of severe disability in the young. In acute management of brain trauma, new approaches based on experimental animal investigations should be sought. METHODS: Twenty male, juvenile Chinchilla-Bastard rabbits received standardized cold-injury-induced-brain-trauma (CIBT). A metal probe (temperature -196 degrees C) was applied epidurally over 10 s. The hyperbaric oxygenation (HBO) group (n=10) underwent 90-min HBO sessions with 100% oxygen at 2.5 atmospheres absolute (1 h, 24+/-2 h, 48+/-2 h after CIBT). Cerebral tissue pO2-measurements were performed 60 min after CIBT, during the three HBO sessions and on day 4. The control group (n=10) underwent no treatment. Animals were sacrificed on day 4, and brains were analyzed histologically. RESULTS: In the HBO group, pO2 measurements showed a significant increase in pO2 between day 1 and day 4, whereas no significant changes were observed in the control group. During the first HBO session, mean pO2 was 169 mm Hg, during the second 305 mm Hg and during the third 420 mm Hg. The mean area of necrosis was 16.2 mm2 in the HBO group, in the control group 19.9 mm2. The areas of brain edema were significantly smaller in the HBO group. Mortality in the HBO group was 0%, in the control group 20%. CONCLUSION: HBO appears to be beneficial as an adjunct treatment of severe head trauma. To find optimal treatment protocols, further clinical studies must be developed.

Animals↗
PubMed2004

Cavernous malformations--navigational supported surgery.

OBJECTIVE: Navigational supported surgery of intracranial lesions is expected to be associated with a lower rate of brain traumatization as well as an avoidance of additional neurological deficits and surgical morbidity. In our study we used the computer-assisted image guidance for resection of cerebral cavernous malformations. METHODS: In all patients the planning procedure for the following image-guided surgery was realized using preoperative MRl data sets and a neuronavigation system (STP 4.0, SNN). In cases in which the cavernoma was situated near functional eloquent regions, functional MR images were fused preoperatively. RESULTS: During the last 24 months, 21 patients were surgically treated for cerebral cavernoma. No patient was operated twice. The mean size of cavernoma was 18.3 mm, ranging from 5 to 60 mm, the mean distance between cortical surface and cavernoma was 26 mm, ranging from 5 to 50 mm. The surgical procedure lasted in the median 180 min. All patients showed an identical or better neurological outcome. CONCLUSIONS: Neuronavigation allows an accurate definition of the intraoperative target, a correct approach and a safe surgery. With the help of neuronavigation the surgical approach and the extirpation of cavernous malformations were realized in a comfortable and safe way and allowed a minimization of tissue manipulation.

Adolescent↗
PubMed2003

[Neuropathological findings after cardiac surgery-retrospective study over 6 years].

Neuropathological studies may contribute to the discovery of central nervous system complications after heart surgery and thus help to reduce the incidence of postoperative neurological or cognitive disturbances. We examined the brains of 262 such patients operated for coronary bypass, valve replacement, or heart transplantation. Circulatory disturbances (macro- and microhemorrhages, infarcts, subarachnoid hemorrhages, and hypoxemic brain damage) were present in 128 cases (49%), as the cause of death in 33 cases (12.6%). The infarcts were caused by local arteriosclerosis of brain arteries, arterial emboli originating from the operative sites or myocardial infarctions, or by fat emboli, foreign body emboli or megakaryocytic capillary emboli in rare cases. Inflammatory disturbances were present in 17 cases and consisted of fungal or bacterial septicopyemic changes (12) or of glial nodules (5) as the substrate of a viral or autoimmunencephalitis (Bickerstaff). An incidental finding was Alzheimer's disease in 37 cases (14% of the material) of elderly patients, often associated with cerebral amyloid angiopathy but not as cause of death or cause of macroscopic brain hemorrhage. Since we have conducted an autopsy study, there is a limitation to transfer the documented changes to the total group of post-cardiac surgery patients with neurologic and cognitive deficits. Contrary to some previous reports, histologically overt microembolic phenomena do not seem to play a major role in our material. On the other hand, careful scrutiny revealed non-fatal white matter microhemorrhages of varying frequency in the different groups, especially after valve operations. These as well as the occasional glial nodules, after resorption and microscarring, could well be the cause of slight neurologic and cognitive impairments.

Aged↗
PubMed2002

Optical properties of selected native and coagulated human brain tissues in vitro in the visible and near infrared spectral range.

Medical laser applications require knowledge about the optical properties of target tissue. In this study, the optical properties of selected native and coagulated human brain structures were determined in vitro in the spectral range between 360 and 1100 nm. The tissues investigated included white brain matter, grey brain matter, cerebellum and brainstem tissues (pons, thalamus). In addition, the optical properties of two human tumours (meningioma, astrocytoma WHO grade II) were determined. Diffuse reflectance, total transmittance and collimated transmittance of the samples were measured using an integrating-sphere technique. From these experimental data, the absorption coefficients, the scattering coefficients and the anisotropy factors of the samples were determined employing an inverse Monte Carlo technique. The tissues investigated differed from each other predominantly in their scattering properties. Thermal coagulation reduced the optical penetration depth substantially. The highest penetration depths for all tissues investigated were found in the wavelength range between 1000 and 1100 nm. A comparison with data from the literature revealed the importance of the employed tissue preparation technique and the impact of the theoretical model used to extract the optical coefficients from the measured quantities.

Brain↗
PubMed2002

[Creutzfeldt-Jakob disease. Lack or correlation between cerebral cortex histology and clinical course of the disease in 22 autopsy cases].

To detect a possible correlation between the neurology and duration of Creutzfeldt-Jakob disease (CJD) and cerebral pathology, we studied 22 autopsy cases by histological and immunohistochemical methods. The duration of disease ranged between 1 and 15 months with an average of 5.2 months. Only in 11 cases was the EEG typical for CJD. Morphologically the changes varied from minimal spongy changes to severe neuronal loss and brain atrophy. For the three cortical regions examined semiquantitatively, there was no correlation between the severity of spongiform changes and the duration of disease or the pattern of neurological symptoms. The study shows that more extensive sampling for the detection of regional heterogeneity of changes is mandatory in spongiform encephalopathies, and that complicating changes such as intermittent infections may play a role for the survival time as well. Moreover, genetic determinants, prion protein polymorphisms and the mode of exposure have to be considered as possible modulating factors.

Aged↗
PubMed2002

[A giant malignant tumour of the skull-Case report and differential diagnosis].

The case of a 72-year-old woman with a high-partially located tumor grown within a half year to a magnitude of 8.5 x 11 x 11 cm is reported. The patient remembered a mastectomy and axillary lymphadenectomy followed by chemotherapy and radiation 8 years ago. Therefore we assumed a skeletal metastasis of a breast cancer. After wide excision, an unusual morphology was found, allowing only a classification as a pleomorphic sarcoma. Searching for the pathohistological evaluation of the former breast tumor, a cystosarcoma phylloides malignum could be found out. The tumor described here can be identified as a metastasis of this rare neoplasm.

Aged↗
PubMed2001

Minor tumour shrinkage in nonfunctioning pituitary adenomas by long-term treatment with the dopamine agonist cabergoline.

OBJECTIVE: The purpose of this study was to define safety and efficacy of medical therapy in the treatment of nonfunctioning pituitary tumours. DESIGN: We studied thirteen patients with a clinically nonfunctioning pituitary macroadenoma for response to cabergoline treatment for 1 year. Twelve/13 patients were already operated and had residual or recurrent tumours. METHODS: We determined the outcome of treatment by visual perimetry, computed tumour size measurement in MRI and hormonal response (changes in pituitary function, reduction of alpha-subunit). RESULTS: Seven/13 patients on cabergoline had a tumour shrinkage above 10% of the initial tumour volume. In 4 patients, this tumour shrinkage was correlated to an increasing distance of the tumour to the optic chiasm. Only 2/9 patients with visual field defects before therapy showed improvements in visual acuity under cabergoline. No significant side effects of the therapeutical regimens were observed. Neither LH and/or FSH expression in the tumour cells nor the reduction of the alpha-subunit serum levels by medical therapy was correlated to tumour shrinkage. CONCLUSION: Given that these patients had advanced disease which makes it difficult to find significant therapeutic effects, medical therapy with potent dopamine agonists such as cabergoline may evolve as a novel therapeutic option in a subgroup of patients with clinically nonfunctioning tumours declining operation and radiotherapy.

Adenoma↗
PubMed2001

Unusual triplet expansion associated with neurogenic changes in a family with oculopharyngeal muscular dystrophy.

The occasional observation of neurogenic features in oculopharyngeal muscular dystrophy (OPMD) is unclear both in nosological and in etiological respects. Studies are reported here of a family with autosomal-dominant OPMD involving seven members over three generations. In three of them muscle biopsies were performed. Two of the patients (a 45-year-old sister and a 57-year-old brother of the third generation) were studied in more detail and, in addition to the typical changes of OPMD, showed a neurogenic component both by electrophysiology and morphology. Molecular genetic investigations revealed a repeat unit of (GCG/GCA)13 in the first exon of the poly(A)binding-protein2 gene in both siblings. A possible association of this unusually long triplet repeat extension with the atypical phenotype is considered and has to be verified in other cases.

Biopsy↗
PubMed2001

Reducing body myopathy with cytoplasmic bodies and rigid spine syndrome: a mixed congenital myopathy.

At the age of five years a male child started to develop a progressive rigid spine, torsion scoliosis, and flexion contractures of his elbows, knees, hips, and ankles owing to severe proximal and distal muscle weakness. He had three muscle biopsies from three different muscles at ages 7, 11, and 14 years, respectively. Myopathologically, these muscle tissues contained numerous inclusions which, at the ultrastructural level, turned out to be reducing bodies and cytoplasmic bodies, often in close spatial proximity. Similar histological inclusions, although not further identified by histochemistry and electron microscopy, were seen in his maternal grandmother's biopsied muscle tissue who had developed weakness of the legs and hands after the age of 50 years. The patient's parents were healthy, but the mother's quadriceps muscle showed an increased spectrum of muscle fibre diameters. Our patient, thus, had a neuromuscular disorder, perhaps familial, presenting as a mixed congenital myopathy, i.e., reducing body myopathy with cytoplasmic bodies, of which the morphological lesions could be consistently documented over several years in his different limb muscles. While other mixed congenital myopathies had shown cores and rods, both related to sarcomeres and thus possibly morphogenetically related, cytoplasmic bodies thought to be related to Z-bands and reducing bodies dissimilar to any muscle fibre constituent do not share any common denominator. Therefore, we suggest that this neuromuscular disorder may be a unique mixed congenital myopathy, either sporadic or genetic. In the latter case, the transmission pattern suggested X-linked recessive inheritance, but an autosomal-dominant transmission with variable penetrance could not be ruled out.

Adult↗
PubMed2001

Gross-total surgery of supratentorial low-grade gliomas under intraoperative MR guidance.

BACKGROUND AND PURPOSE: Length of survival of patients with low-grade glioma correlates with the extent of tumor resection. These tumors, however, are difficult to distinguish intraoperatively from normal brain tissue, often leading to incomplete resection. Our goal was to evaluate the effectiveness of intraoperative MR guidance in achieving gross-total resection. METHODS: We studied 12 patients with low-grade glioma who underwent surgery within a vertically open 0.5-T MR system. During surgery, localization of residual tumor tissue was guided by interactive, near real-time imaging. The amount of residual tumor tissue on MR images was evaluated at the point of the operation at which the neurosurgeon would have terminated the procedure under conventional conditions (first control) and again before closing the craniotomy. RESULTS: Significant residual tumor (more than 10% of original tumor volume) was shown in eight patients at the first control condition. The percentage of resection varied from 26% to 100% (mean, 68%) at this time. Twelve tissue samples from seven patients were obtained in areas identified as residual tumor on MR images. In 10 cases, the neuropathologic investigation confirmed the presence of residual low-grade glioma; in two cases, the borderzone of tumor was identified. In evaluating the final sets of images, we found total resection in six cases, over 90% resection in five cases, and 85% resection in one case (mean, 96%). CONCLUSION: Surgical treatment of low-grade gliomas under intraoperative MR guidance provides improved resection results with maximal patient safety.

Adult↗
PubMed2000

Alzheimer-related tau-pathology in the perforant path target zone and in the hippocampal stratum oriens and radiatum correlates with onset and degree of dementia.

Abnormal phosphorylation of the tau-protein is regarded as a crucial step in the formation of neurofibrillary tangles in the neuronal cell body and neuropil threads in dendrites. We studied the effects of tau-pathology on the clinical expression of dementia in 106 autopsy cases in the entorhinal region, the hippocampal stratum oriens, the stratum radiatum, and the perforant path target zone. The first cytoskeletal lesions were located in the perikarya and dendrites of the pre-alpha cells of the transentorhinal and entorhinal region. Next, abnormally phosphorylated tau-protein (PHF-tau) was found in the neuropil of the CA1-subiculum region. Thereafter, the stratum radiatum and stratum oriens began to be involved in PHF-tau pathology in Braak stage II. In the Braak stages IV and V, the stratum radiatum was completely involved, the stratum oriens increasingly so. Beginning in Braak stage III, we noted cases having PHF-tau pathology in the perforant path target zone of the outer molecular layer of the dentate gyrus. The increase of this pathology with ever greater involvement on the part of the entorhinohippocampal circuit correlated significantly not only with the Braak stages and with the neurochemically determined hippocampal content of PHF-tau but also with the degree of dementia as defined by the clinical dementia rating (CDR) scale. The affection of the stratum oriens in combination with PHF-tau pathology in the stratum radiatum and in the outer molecular layer of the dentate gyrus was encountered almost exclusively in demented individuals (CDR 1-3). These results indicate that axonal PHF-tau pathology in hippocampal pathways presumably is critical for the clinical expression of dementia and may constitute an anatomical substrate of clinically verifiable memory dysfunction in Alzheimer's disease.

Aged↗
PubMed1999

[Cytophotometric investigations in recurrent gliomas: correlation of DNA-parameters with WHO-grade, proliferation index and recurrence-free interval].

DNA-cytophotometry is one of the methods that may contribute to a more precise evaluation of the biological behaviour of tumours in addition to the WHO-classification. In this study 121 tumour specimens of 50 patients suffering from gliomas with one or up to three recurrencies were investigated. In all cases the histological type and WHO-grade and the Ki-67/MIB1 labeling index were determined. DNA cytophotometry was performed after single cell preparation on Feulgen-stained preparations, and the following parameters were calculated: stemline ploidy, 5c-exceeding rate, and 2c-deviation index. Statistical evaluation revealed a highly significant correlation between recurrence-free interval and WHO-grade only. The DNA parameters, however, furnished additional information about increasing genetic instability in the majority of the recurrencies independently of changes in the WHO-grade. They thus seem to be useful as additional parameters for the determination of glioma progression.

Adult↗
PubMed1999

Preliminary experience with interactive guided brain biopsies using a vertically opened 0.5-T MR system.

The purpose of our study was to evaluate the feasibility and accuracy of brain biopsies performed within a vertically opened MR system. We worked with the interventional 0.5-T MR "SIGNA SP" (General Electric Medical Systems, Milwaukee, Wis.) with an integrated tracking device "Flashpoint Position Encoder" (Image Guided Technologies, USA). As a holding device for this instrument we constructed a special frame. The whole system allows an exact adjustment of an optimum biopsy direction and guidance of the biopsy in a non-stereotactic, interactive mode in near real-time. As biopsy tools we used MR-compatible aspiration and specially made side-cut needles (Daum, Germany; E-Z-EM, USA). We performed a prospective diagnostic brain biopsy study in 18 patients. Guidance of the needle was carried out using gradient-echo single-slice technique. The sample was taken after controlling the exact position of the needle tip on spin-echo images. In 12 cases an exact neuropathological diagnosis was possible. In 6 cases of negative biopsy (4 aspiration biopsies) the samples were not representative. Our results demonstrate the feasibility of interactive MR-guided minimally invasive brain biopsies in an open MR system. The best results were achieved using cut needles for biopsies of contrast-enhancing lesions visible on T1-weighted gradient-echo guidance sequence.

Adult↗