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Biomedical subjects

R Schober

Publications and source records attributed to R Schober.

At least 37 records · Page 2Linked to original sources
PubMed1998

Rhinocerebral zygomycosis following bone marrow transplantation in chronic myelogenous leukaemia. Report of a case and review of the literature.

We report on a man suffering from chronic myelogenous leukaemia treated by allogeneic bone marrow transplantation who, in the late post-transplantation phase, developed a hyperacute fatal invasive rhinocerebral zygomycosis. The origin of the ascending infection was the sinus sphenoidalis from which fungal hyphae spread to the central nervous system via the skull and the dura mater. The first symptoms of this severe infection were cerebral convulsions and a bilateral total amaurosis. The isolation of the pathogen from post mortem tissue was not successful. The present case is compared with previous reports of zygomycoses after bone marrow transplantation.

Adult↗
PubMed1998

Stage-correlated distribution of type 1 and 2 dystrophic neurites in cortical and hippocampal plaques in Alzheimer's disease.

Two types of dystrophic neurites have been described in neuritic plaques in Alzheimer's disease (AD). Type 1 dystrophic neurites display tau-positive paired helical filaments (PHF) while those of type 2 are swollen and positive for both amyloid precursor protein and Chromogranin A. To determine the role of these two types of dystrophic neurites in the development of neuritic plaques, we examined their distribution in CA 1, CA 4, the entorhinal and the temporal cortex throughout all Braak-stages. Fourty cases with AD-related neurofibrillary changes were evaluated semi-quantitatively. The frequency of neuritic plaques displaying both types of dystrophic neurites seemed to increase from stage I to stage IV and to remain stable or slightly decrease in later stages. Staining combinations detecting type 1 (Gallyas, immunohistochemistry against hyperphosphorylated tau-protein) and type 2 dystrophic neurites simultaneously (immunohistochemistry against the amyloid precursor protein or Chromogranin A) showed coexpression of the type 1 and type 2 pattern in single neurites of neuritic plaques. In the entorhinal and temporal cortex, occasional neuritic plaques displayed tau-immunopositive changes in the absence of swollen type 2 neurites. Since amyloid precursor protein is expressed in distal ends of neurites after various brain lesions we suggest that amyloid precursor protein-positive neurites in neuritic plaques indicate dysfunctional axonal transport due to type 1 neurofibrillary changes.

Aged↗
PubMed1997

The subunits of alpha2-macroglobulin receptor/low density lipoprotein receptor-related protein, native and transformed alpha2-macroglobulin and interleukin 6 in Alzheimer's disease.

To explore the role of alpha2-macroglobulin receptor/low density lipoprotein receptor-related protein (alpha2M-R/LRP) and its ligands in the pathogenesis of Alzheimer's disease (AD), antibodies were raised against its alpha- and beta-subunits and their expression pattern in the CNS in AD and control cases was correlated with that of native and transformed alpha2-macroglobulin (alpha2M) and interleukin 6 (IL-6). The transmembranous beta-subunit of alpha2M-R/LRP and transformed alpha2M were found in plaque cores in AD. Extramembranous alpha-subunit and native alpha2M immunoreactivities were localized in activated plaque-associated astrocytes and extracellularly in plaques. IL-6 immunostaining was associated with neurofibrillary changes, and was also found extracellularly in the center of plaques and in microglial cells. Our finding that plaque cores contain a second transmembranous protein fragment, the beta-subunit of alpha2 M-R/LRP, suggests ongoing membrane-protein degradation. By altering clearance and scavenger-like functions, fragmentation and breakdown of alpha2M-R/LRP may have an important role in extracellular amyloid deposition and the formation of neurofibrillary tangles in AD.

Alzheimer Disease↗
PubMed1997

Differential pattern of beta-amyloid, amyloid precursor protein and apolipoprotein E expression in cortical senile plaques.

Regional differences in senile plaques immunostained by antibodies against beta-amyloid A4 (beta-A4), amyloid precursor protein 695 (APP) and apolipoprotein E (apo E) were studied in the hippocampus and the entorhinal, temporal and occipital cortices both quantitatively and semiquantitatively with respect to the laminar cortical distribution of the plaques. These patterns were related to the staging of Alzheimer's disease in regard to the distribution of neurofibrillary tangles (Braak and Braak (1991) Acta Neuropathol 82: 239-259). In the hippocampus and especially in sector CA 1, no significant differences in the number of plaques visualized by the different antibodies were found. In contrast, there was a striking difference in neocortical regions. Here, significantly higher numbers of plaques positive for beta-A4 than that for APP and apo E were present in all stages, except in the stages I and VI, and for apo E in stage II. The highest densities of beta-A4-positive plaques were found in the isocortical layers III and V and in the entorhinal pre-alpha, pre-gamma, pri-alpha and pri-beta layers. The preferentially affected area, showing plaques positive for all three antibodies, was the entorhinal-hippocampal circuit with early affection of CA 1, which represents the direct and indirect target of the entorhinal neurons of the upper layers. Therefore, we suggest that plaques with dystrophic neurites, positive for APP, seem to be generated secondarily in afferent areas such as the hippocampus, which is the main afferent target of the entorhinal region. Diffuse plaques, negative for APP and apo E, are virtually absent in the CA 1 and seem to originate independently of afferent neuronal dysfunction, as indicated by neurofibrillary tangles.

Alzheimer Disease↗
PubMed1995

Multiple paraneoplastic syndromes in a patient with antibodies to neuronal nucleoproteins (anti-Hu).

We report the clinical and autopsy studies of a patient with an unusual combination of multiple paraneoplastic neurological syndromes in association with antibodies to a 35-40 kDa neuronal nucleo-protein (anti-Hu). Neurological disease preceded the detection of a small cell carcinoma of the lung. The patient had combined sensory and motor neuronopathy or neuropathy, cerebellar degeneration, brain-stem and limbic encephalitis, and clinical evidence of the Lambert-Eaton myasthenic syndrome and gastrointestinal pseudo-obstruction of paraneoplastic origin.

Autoantibodies↗
PubMed1993

Fine structure of zonal changes in experimental Nd:YAG laser-induced interstitial hyperthermia.

Interstitial thermotherapy using Nd:YAG-laser induced hyperthermia is a new stereotactic method for the treatment of brain tumors in poorly accessible regions. To provide a basis for the underlying tissue alterations, we have analyzed the spatial and temporal pattern of interstitial laser hyperthermia lesions in the normal rat brain by histological, immunohistochemical, and electron microscopical methods. The acute changes corresponded to the temperature gradient surrounding the laser probe and showed a distinct zonal architecture. Membrane destruction on a cellular and subcellular level appears to be of major significance in the pathogenesis of the laser lesion. The tissue reaction followed the course known for coagulation necrosis and resulted in a well-defined defect. These results, although limited by the choice of the experimental model, may be helpful in the interpretation of images obtained in future applications of interstitial thermotherapy.

Aluminum Silicates↗
PubMed1993

Symmetrical neurofibroma with Schwann cell predominance and focal formation of microneurinomas.

A case of symmetrical neurofibroma with onion bulbs in various stages of development and progression to microneurinomas is presented. Immunohistochemistry with differentiation and growth factor markers as well as electron microscopy showed a Schwann cell origin of the concentrically arranged cells. The onion bulbs differed from those of hypertrophic neuropathy by their more compact structure. A partial expression of cellular proliferation markers in the onion bulbs was consistent with a multifocal proliferative activity, confirming the neoplastic nature of the lesion.

Adult↗
PubMed1992

Gliofibroma: immunohistochemical analysis.

A case of gliofibroma occurring in an adult patient as a large circumscribed supratentorial tumor is reported. The bimorphic pattern was substantiated and further analyzed by immunohistochemistry. Some evidence in favor of collagen production by mesenchymal and/or inflammatory cells leading to a progressive fibrous replacement of the glial cells in this particular tumor type is presented.

Adolescent↗
PubMed1992

Occlusive microangiopathy by immunoglobulin (IgM-kappa) precipitation: pathogenetic relevance in paraneoplastic cryoglobulinemic neuropathy.

Histological, immunohistochemical and ultrastructural sural nerve and skin biopsy findings in a case of cryoglobulinemia secondary to an IgM-kappa-producing non-Hodgkin lymphoma are described. The main finding was an occlusive microangiopathy present in both the sural nerve and the skin. Widespread cryoglobulin deposits of the proliferated vasa nervorum were associated with pronounced changes probably evoked by ischemia. Moderate perivascular inflammation, but no florid vasculitis was additionally present. Our observations indicate that occlusive microangiopathy by precipitated cryoglobulins may be a relevant pathogenetic factor in cryoglobulinemic peripheral neuropathy.

B-Lymphocytes↗
PubMed1992

Vascular permeability changes in tumours of the peripheral nervous system.

Vascular permeability changes were examined in 34 tumours of the peripheral nervous system by immunohistochemical demonstration of serum proteins as endogenous tracers. The blood-tumour barrier was impaired in the reticular (Antoni type B) portions of neurinomas (Schwannomas) and in cutaneous neurofibromas but was similar to the normal blood-nerve barrier in fibrillary (Antoni type A) neurinomas, in most neurofibromas, in ganglioneuromas and in anaplastic tumours. These differences in permeability are discussed in relation to aspects of pathological tumour vascularization, the histogenesis of microcystic changes, and systemic therapeutic approaches.

Adult↗
PubMed1992

Immunotherapy with stimulated autologous lymphocytes in a case of a juvenile anaplastic glioma.

The effect of immunotherapy with stimulated autologous lymphocytes (SAL) in malignant gliomas is documented and discussed in a bioptical and autoptical case study. A five-year-old child with a recurrently operated and radiated right hemispheric anaplastic astrocytoma died six weeks after immunotherapy with mitogen-activated killer cells and recombinant Interleukin-2. The autopsy revealed a large butterfly glioma with partially necrotic gelatinous tissue at the site of the SAL reservoir. The tumor cell density on the right was less than on the left hemisphere, and T-lymphocyte content was higher on the right hemisphere. These results demonstrate a local effect of SAL therapy in vivo, although the tumor progression as a whole could not be stopped. They also demonstrate the need of a detailed neuropathological examination in all cases of immunotherapy of malignant gliomas.

Brain Neoplasms↗
PubMed1991

Stereotactic laser therapy in cerebral gliomas.

The 1.06 micron Nd:YAG laser and a new fiberoptic delivery system, the Interstitial Thermo-Therapy (ITT) laser fibre, allows stereotactic interstitial irradiation of cerebral tumours. In experimental rat brain studies we found typical laser-tissue effects with a central necrosis and a sharply demarcated oedema towards the normal brain. The size of the lesion depended on the energy and exposure time applied. In a pilot series we treated 5 patients with cerebral gliomas WHO grade II-III in functionally important regions and monitored the therapeutic effects by MR imaging and PET scan. Early post-operative results showed irreversible necrotic changes in the tumour centre and reversible oedematous changes at the tumour margin. Long-term results will show if stereotactic interstitial laser therapy is a useful supplementary method in the treatment of malignant cerebral tumours.

Animals↗
PubMed1991

Gliomatosis cerebri: bioptical approach and neuropathological verification.

Gliomatosis cerebri is rarely encountered and its intra vitam diagnosis has remained difficult. We present biopsy and autopsy findings in three cases that are representative of diffuse glioma, gliomatosis cerebri and diffuse glioblastosis, a modification of the subclassification proposed by Zülch31. Stereotactic biopsy in conjunction with nuclear magnetic resonance tomography (MRT) is recommended as the diagnostic procedure in suspected cases. Immunohistochemical examination with a panel of neuroectodermal markers is helpful in the differential diagnosis but has to take into account that reactive astrocytes may be closely intermingled with the neoplastic glial cells.

Adult↗
PubMed1991

Encephalo-myelo-radiculo-ganglionitis presenting as pandysautonomia.

A 68-year-old man developed pandysautonomia with severe orthostatic dysfunction, fixed heart rate, low serum levels of norepinephrine and epinephrine, absent sympathetic skin responses, and pupillary abnormalities. CSF protein was 92 mg/dl. In spite of a good recovery following corticosteroid administration, a relapse occurred, with accompanying sensory symptoms confined to both arms. Fatal sudden cardiac arrest occurred after 4 months. Autopsy revealed numerous lymphocytic infiltrates, predominantly in autonomic and sensory ganglia and, to a lesser extent, in the nerve roots, spinal cord, and brainstem without evidence for an underlying tumor. This case provides histopathologic evidence for an inflammatory etiology of panautonomic neuropathy in some patients.

Aged↗