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  • 11
    Electronic Resource
    Electronic Resource
    Amplification of the cyclin-dependent kinase 4 (CDK4) gene is associated with high cdk4 protein levels in glioblastoma multiforme (1996)
    Springer
    Acta neuropathologica 92 (1996), S. 70-74 
    Details
    ISSN: 1432-0533
    Keywords: Key wordsCDK4 ; Gene amplification ; Protein level ; LOH12q ; Brain tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Genetic alterations on the long arm of chromosome 12, including both gene amplification and allelic loss, are associated with malignant progression of human gliomas. The region of the chromosomal arm 12q that is amplified in malignant gliomas contains the CDK4 gene, a cell cycle regulatory gene which promotes cell division. To evaluate the frequency of CDK4 gene amplification, we analyzed a series of 355 brain tumors using a quantitative non-radioactive polymerase chain reaction assay. CDK4 gene amplification occurred in 9 of 81 glioblastomas (11%), but was rare in other neoplasms, including low-grade and anaplastic gliomas, meningiomas, medulloblastomas and metastatic carcinomas (only 6 of 274 cases). There was no correlation between CDK4 gene amplification and allelic loss of chromosome 12. To assess the significance of CDK4 gene amplification, we analyzed protein extracts from 37 glioblastomas by Western blotting with a commercially available polyclonal antibody to cdk4. All tumors with CDK4 gene amplification showed high cdk4 expression levels, whereas no increased cdk4 expression was seen in glioblastomas without CDK4 gene amplification. These data support the functional activity of CDK4 gene amplification in glioblastoma multiforme and point to an important role of CDK4 gene amplification in a subset of glioblastomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050491
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  • 12
    Electronic Resource
    Electronic Resource
    Altered distribution of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor subunit GluR2(4) and the N-methyl-d-aspartate receptor subunit NMDAR1 in the hippocampus of patients with temporal lobe epilepsy (1996)
    Springer
    Acta neuropathologica 92 (1996), S. 576-587 
    Details
    ISSN: 1432-0533
    Keywords: Key words Excitatory amino acids ; Therapy-refractory epilepsy ; Ammon’s horn sclerosis ; Quantitative image analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In patients with therapy-refractory temporal lobe epilepsy (TLE), alterations of glutamate receptors have been proposed as a mechanism for enhanced excitability. Using commercially available monoclonal antibodies specific for the N-methyl-d-aspartate (NMDA) receptor subunit NMDAR1 and for the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor subunit GluR2(4), we have examined the distribution of these polypeptides in human hippocampal tissue that was surgically removed from patients with intractable TLE. Surgical specimens were classified according to the presence of Ammon’s horn sclerosis (AHS) or a focal lesion in the temporal lobe. Cell counts and a densitometric analysis of the immunoreactivity patterns were carried out for all hippocampal subfields. NMDAR1 and GluR2(4) levels were markedly reduced in patients with AHS, primarily in those subfields with substantial neuronal cell loss (in particular CA1, CA4 and CA3), compared to those seen in patients with focal lesions and in control specimens obtained at autopsy. In contrast, the molecular layer of the dentate gyrus (DG-ML) showed significantly higher levels of GluR2(4) immunoreactivity in AHS compared to control tissue, while NMDAR1 showed no significant up-regulation in this sublayer. When the receptor staining intensity was normalized for alterations in neuronal density, no significant alterations could be detected except for an increase in GluR2(4) in the DG-ML of patients with AHS. These changes may reflect synaptic reorganization observed in the DG-ML of specimens from patients with chronic intractable TLE.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050564
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  • 13
    Electronic Resource
    Electronic Resource
    Tuberous sclerosis-like lesions in epileptogenic human neocortex lack allelic loss at the TSC1 and TSC2 regions (1996)
    Springer
    Acta neuropathologica 93 (1996), S. 93-96 
    Details
    ISSN: 1432-0533
    Keywords: Key words Chromosome 9 ; Chromosome 16 ; Epilepsy ; Hamartoma ; Pathology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Glioneuronal malformations with a striking histological resemblance to cortical tubers of tuberous sclerosis, but no extracerebral stigmata of this phacomatosis, are frequently encountered in patients with chronic pharmacoresistant epilepsies. It is controversial as to whether these lesion represent a forme fruste of tuberous sclerosis or a distinct entity. The recently reported loss of heterozygosity (LOH) at the regions of the TSC1 or TSC2 locus in hamartomas obtained from different organs of patients with established tuberous sclerosis, including cortical tubers, stimulated us to examine epilepsy-associated tuberous sclerosis-like glioneuronal malformations with respect to LOH at the TSC1 and TSC2 loci of chromosomes 9q34 and 16p13.3, respectively. The analysis was carried out on DNA derived from paraffin-embedded brain tissues of 11 patients. For 5 patients, peripheral blood leukocytes were also available for DNA extraction. We performed microsatellite analysis with five markers on chromosome 9 and four markers on chromosome 16. In addition, polymerase chain reaction-restriction fragment length polymorphism (RFLP) analysis was performed using a polymorphic EcoRV restriction site in exon 40 of the TSC2 gene. No LOH was identified in any of the cases. These findings do not support a relationship between the epilepsy-associated glioneuronal lesions and tuberous sclerosis. However, tuberous sclerosis is genetically heterogeneous and microsatellite and RFLP analysis cannot exclude small deletions or point mutations. Thus, given the histopathological similarity of glioneuronal malformations in epilepsy patients to cortical tubers, further molecular genetic studies will be needed as our understanding of the molecular basis of tuberous sclerosis increases to completely clarify the relationship of these lesions to tuberous sclerosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050587
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  • 14
    Electronic Resource
    Electronic Resource
    Hippocampal loss of N-methyl-D-aspartate receptor subunit 1 mRNA in chronic temporal lobe epilepsy (1995)
    Springer
    Acta neuropathologica 89 (1995), S. 446-450 
    Details
    ISSN: 1432-0533
    Keywords: Key wordsN-Methyl-D-aspartate receptor ; Epilepsy ; Non-radioactive in situ hybridization ; Hippocampus ; Ammon's horn sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The hippocampal distribution of mRNA for the N-methyl-D-aspartate (NMDA) receptor subunit 1 (NR1) was examined by non-radioactive in situ hybridization in 21 archival formalin-fixed and paraffin-embedded surgical specimens from patients with pharmacoresistant chronic epilepsy and in normal control specimens obtained at autopsy. Using the digoxigenin-labeling procedure, ribonucleotide probes were found to be significantly more sensitive than synthetic oligonucleotide probes. In normal autopsy specimens and in surgical specimens without Ammon's horn sclerosis there was intense NR1 expression in a great majority of the dentate gyrus granular cells. Many neurons in the hippocampal pyramidal cell layer also revealed a strong signal intensity. The strata oriens and moleculare of Ammon's horn and the molecular layer of the dentate gyrus contained only few labeled neurons. In the subiculum and entorhinal cortex most neurons throughout various layers were positive. In hippocampal specimens of patients with chronic epilepsy there was a loss of NR1-positive cells that was closely related to the overall neuronal loss in the respective specimen and to Ammon's horn sclerosis. These data suggest that the loss of NR1 expression is a secondary phenomenon rather than an event that is relevant for the pathogenesis of epileptic seizures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307650
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  • 15
    Electronic Resource
    Electronic Resource
    Apoptosis and apoptosis-related gene products in primary non-Hodgkin’s lymphoma of the central nervous system (1998)
    Springer
    Acta neuropathologica 96 (1998), S. 157-162 
    Details
    ISSN: 1432-0533
    Keywords: Key words Central nervous system ; Lymphoma ; B cell ; Apoptosis ; bcl-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The incidence of primary lymphomas of the central nervous system (CNS) has significantly increased over the last years. However, the pathogenesis of this serious and fatal disease is still largely unknown. The aim of the present study was to investigate whether impairment of apoptosis is involved in the pathogenesis of primary CNS lymphomas. A series of 35 primary CNS lymphomas was investigated for the presence of apoptotic cells and the expression of apoptosis-inhibiting and proapoptotic gene products of the bcl family by application of the terminal deoxynucleotidyl transferase-mediated dUTP-nick end labeling (TUNEL) technique and immunohistochemistry. The majority (23/35) of the tumors contained no or less than 10% of apoptotic cells. All tumors were MIB-1 positive, and 53% of them showed a high proliferative activity with more than 20% MIB-1-positive cells. The bcl-2 gene was expressed in 54% of the tumors (19/35), whereas bcl-x and bax gene products were present in only a low fraction of these lymphomas (4/35). In contrast, bak and the tumor suppressor gene p53 product were not detectable. These findings indicate that apoptosis is inhibited in the majority of this series of primary CNS lymphomas. Since there was no statistical correlation between the degree of apoptosis and the expression of proteins of the bcl gene family, other apoptosis-inhibiting factors may be involved in the pathogenesis of primary CNS lymphomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050876
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  • 16
    Electronic Resource
    Electronic Resource
    An experimental model for infiltration of malignant lymphoma to the eye and brain (1997)
    Springer
    Virchows Archiv 431 (1997), S. 459-467 
    Details
    ISSN: 1432-2307
    Keywords: Key words Metastasis ; CNS lymphoma ; Ocular lymphoma ; S49
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Currently there is no adequate experimental model available whereby the lethal infiltration of malignant lymphoma to the eye and CNS can be studied. Variant S49 mouse lymphoma cells that exhibit cell-cell adhesion properties (named Rev-2-T-6) were inoculated intraperitoneally into Balb/C mice at the ages of 6–60 days postnatal. Mice inoculated between days 6–11 postnatal developed signs of eye and CNS involvement with an apparent peak (58% of mice) at day 7. None of the mice inoculated beyond day 11 exhibited such signs. Histological analysis of these sites revealed tumorous infiltrates into a variety of structures in the orbit, intraocular tissues, along the optic nerve and in the brain. Additional analysis of the histopathological data, based on the structures demonstrating the highest frequency of lymphoma infiltration, suggests preferred routes of lymphoma entry to the brain and eye. Thus, entry to the brain can occur mainly through the choroid plexus and cranial nerves or cranial nerve ganglia. Entry to the eye may occur from the brain (along the optic nerve), and through hematogenous infiltration of orbital structures. No data were found that would support retrograde infiltration of the lymphoma from the eye to the brain. These findings present an experimental model for addressing the molecular mechanisms that govern homing of malignant lymphoma to the eye and brain, as well as the development of experimental therapeutic modalities for malignant lymphoma in these organs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004280050124
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  • 17
    Electronic Resource
    Electronic Resource
    Analysis of a polymorphism in the tuberous sclerosis (TSC2) gene does not predispose to schizophrenia (1998)
    Springer
    European archives of psychiatry and clinical neuroscience 248 (1998), S. 314-315 
    Details
    ISSN: 1433-8491
    Keywords: Key words Schizophrenia ; SSCP ; TSC2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the development of malformations in various organs including the brain. A polymorphism in the TSC2 gene has been found to be increased in gangliogliomas, a lesion which is associated with disturbed neuro-glial cell migration pattern. Since these pathomorphological changes are compatible with disturbed neuronal migration in schizophrenic brains, we investigated this polymorphism in 130 families with a schizophrenic index patient. A 222-bp fragment of genomic DNA containing the TSC2 variant was analyzed by SSCP. The analysis revealed that there is no association with schizophrenia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004060050056
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  • 18
    Electronic Resource
    Electronic Resource
    Expression and distribution of vascular endothelial growth factor protein in human brain tumors (1997)
    Springer
    Acta neuropathologica 93 (1997), S. 109-117 
    Details
    ISSN: 1432-0533
    Keywords: Key words Vascular endothelial growth factor ; Brain tumor ; Astrocytoma ; Angiogenesis ; Vascularization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Marked neovascularization is a hallmark of many neoplasms in the nervous system. Recent reports indicate that the endothelial mitogen vascular endothelial growth factor (VEGF) may play a critical role in the regulation of vascular endothelial proliferation in malignant gliomas. Using novel monoclonal antibodies to the VEGF polypeptide we have determined the expression and cellular distribution of VEGF protein in a representative series of 171 human central nervous system (CNS) tumors by immunohistochemistry and immunoblotting. In agreement with previous in situ hybridization data, 19 out of 20 glioblastomas (95%) showed immunoreactivity for VEGF, whereas both the percentage of immunoreactive tumors and the extent of immunoreactivity for VEGF were significantly lower in astrocytomas. Of the pilocytic astrocytomas (WHO grade I) 44% were immunoreactive for VEGF, but we observed several cases with pronounced vascular proliferates in the absence of VEGF. In ependymomas, meningiomas, hemangioblastomas, and primitive neuroectodermal tumors, there was no correlation between VEGF expression, vascular endothelial proliferation and the grade of malignancy. Oligodendrogliomas and the oligodendroglial component of mixed gliomas lacked immunoreactive VEGF, indicating that endothelial growth factors other than VEGF may regulate tumor angiogenesis in these neoplasms. Western blot analysis showed a predominant VEGF protein species of 23 kDa and confirmed the immunohistochemical data in all cases. Our findings demonstrate that VEGF is expressed in a wide spectrum of brain tumors in which it may induce neovascularization. However, other angiogenic factors also appear to contribute to the vascularization of CNS neoplasms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050591
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  • 19
    Electronic Resource
    Electronic Resource
    The CD34 epitope is expressed in neoplastic and malformative lesions associated with chronic, focal epilepsies (1999)
    Springer
    Acta neuropathologica 97 (1999), S. 481-490 
    Details
    ISSN: 1432-0533
    Keywords: Key words Stem cell ; Tumor ; Malformation ; Epilepsy ; Ganglioglioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The etiology and pathogenesis of complex focal lesions associated with chronic, intractable epilepsy are largely unknown. Some data indicate that malformative changes of the central nervous system may preceed the development of gangliogliomas and other epilepsy-associated neoplasms. In the present immunhistochemical study, we have examined epilepsy-associated lesions for CD34, a stem cell marker transiently expressed during early neurulation. Surprisingly, most tissue samples from patients with chronic epilepsy (n = 262) revealed neural cells immunoreactive for CD34. Prominent immunoreactivity was detected in gangliogliomas (74%), low-grade astrocytomas (62%) and oligodendrogliomas (59%). Only 52% of non-neoplastic, malformative pathologies, such as glio-neuronal hamartias or hamartomas showed solitary or small clusters of CD34-immunoreactive cells. None of the adult control tissues (n = 22), none of the specimens obtained from the developing human brain (n = 44) and none of those tumor samples from patients without epilepsy (n = 63) contained CD34-immunoreactive neural cells. However, a malignant teratoma with microscopic features of early neural differentiation displayed a focal CD34-immunoreactive staining pattern. The majority of CD34-immunoreactive cells co-localized with S-100 protein and a small subpopulation was also immunoreactive for neuronal antigens. CD34 may, thus, represent a valuable marker for the diagnostic evaluation of neoplastic and/or malformative pathological changes in epilepsy patients. The CD34 immunoreactivity of these lesions indicates an origin from dysplastic or atypically differentiated neural precursors. Further studies may elucidate the functional significance of CD34 expression during the pathogenesis of epilepsy-related focal lesions as well as during neurogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010051017
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  • 20
    Electronic Resource
    Electronic Resource
    Neuronal loss and gliosis of the amygdaloid nucleus in temporal lobe epilepsy (1997)
    Springer
    Acta neuropathologica 93 (1997), S. 606-610 
    Details
    ISSN: 1432-0533
    Keywords: Key words Ammon’s horn sclerosis ; Amygdala ; Hippocampus ; Pathology ; Seizures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although clinical and electrophysiological evidence indicates that the amygdaloid body plays an important role in the pathogenesis of temporal lobe epilepsy, there are very few detailed data on histopathological changes in this nucleus in epilepsy patients. In the present study we have examined the lateral nucleus of the amygdaloid body in 70 surgical specimens from patients with temporal lobe epilepsy and in 10 control specimens with respect to neuronal density and gliosis. The results were compared to the neuronal loss in the hippocampal formation. Our goal was to examine the pathological alterations of the amygdaloid body and their correlation with other morphological changes in temporal lobe epilepsy. In epilepsy patients with Ammon’s horn sclerosis or focal lesions of the temporal lobe, the neuronal density of the lateral amygdaloid nucleus was significantly decreased as compared to normal controls (P 〈 0.001). Overall, the mean volumetric density in epilepsy patients was reduced to 59% of that in normal individuals. There was no correlation between the neuronal density in the lateral amygdaloid nucleus and that in the different segments of the hippocampal formation or to the age at onset or the duration of epilepsy. The neuronal loss of the amygdaloid nucleus correlated well with the presence of fibrillary gliosis. Our findings demonstrate that the amygdaloid body is severely altered in most patients with temporal lobe epilepsy and that these changes are independent of those in the hippocampus. The presence of neuronal loss and gliosis in the amygdaloid nucleus of patients with focal lesions but no Ammon’s horn sclerosis is compatible with an involvement of the amygdala in secondary epileptogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050658
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