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  • 1
    ISSN: 1432-0533
    Keywords: Key words Heme oxygenase-1 ; Heat shock protein-32 ; Traumatic brain injury ; Cerebral infarction ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Extracellular heme derived from hemoglobin following hemorrhage or released from dying cells induces the expression of heme oxygenase-1 (HO-1, HSP-32) which metabolizes heme to the gaseous mediator carbon monoxide (CO), iron (Fe) and biliverdin. Biliverdin and its product bilirubin are powerful antioxidants. Thus, expression of HO-1 is considered to be a protective mechanism against oxidative stress and has been described in microglia, astrocytes and neurons following distinct experimental models of pathological alterations to the brain such as subarachnoidal hemorrhage, ischemia and traumatic brain injury (TBI) and in human neurodegenerative diseases. We have now analyzed the expression of HO-1 in human brains following TBI (n = 28; survival times: few minutes up to 6 months) and focal cerebral infarctions (FCI; n = 17; survival time: 〈 1 day up to months) by ¶immunohistochemistry. Follwing TBI, accumulation of ¶HO-1+ microglia/macrophages at the hemorrhagic lesion was detected as early as 6 h post trauma and was still pronounced after 6 months. In contrast, after FCI HO-1+ microglia/macrophages accumulated within focal hemorrhages only and were absent in non-hemorrhagic regions. Further, HO-1 was weakly expressed in astrocytes in the perifocal penumbra. In contrast to experimental data derived from rat focal ischemia, these results indicate a prolonged HO-1 expression in humans after brain injury.
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  • 2
    ISSN: 1432-0533
    Keywords: Key words Cell culture ; Cell line ; Glioma ; Calcium-binding proteins ; Microglia enzymology ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Allograft inflammatory factor-1 (AIF-1) is a Ca2+-binding peptide that constitutes a potential modulator of macrophage activation and function during the immune response of the brain. Peptides termed microglia response factor-1 or ionized calcium-binding adaptor molecule-1 have been reported to be identical with AIF-1. We have investigated the expression of AIF-1 in the rat C6 glioblastoma and 9L gliosarcoma tumor models and additionally assessed AIF-1 expression in a diverse range of human astrocytomas by immunohistochemistry. AIF-1 was expressed by activated microglial cells and a subset of infiltrating macrophages in areas of infiltrative tumor growth and in compact tumor areas in both rat and human gliomas. Double-labeling experiments in rats and humans characterized the nature and the functional status of AIF-1+ cells. AIF-1 expression was detected in cells expressing major histocompatibility complex class II molecules and in a subset of activated macrophages/microglial cells. All MRP-8+ cells coexpressed AIF-1. In humans, there was a strong correlation of AIF-1-expressing activated macrophages/microglial cells with tumor malignancy (P 〈 0.0001). These results suggest that AIF-1 defines a distinct subset of tumor-associated activated macrophages/ microglial cells.
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  • 3
    ISSN: 1432-0533
    Keywords: Key words Glioma ; Multidrug resistance ; Chemotherapy ; Endothelial ; Blood brain barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human malignant gliomas are commonly resistant to chemotherapy. Here, we examined the role of the multidrug resistance (mdr) mechanism in the chemoresistance of these tumors, using a twofold approach: (i) by assessing a possible mdr phenotype before and after chronic drug exposure of glioma cells in vitro, and (ii) by assessing the modulation of expression of the mdr-associated P-glycoprotein (Pgp) using radiotherapy and serial cycles of chemotherapy in human glioblastoma patients in vivo. T98G, and to a lesser degree, LN-229 human malignant glioma cells exhibit a constitutive mdr phenotype as determined by the modulation of dye transport and by the augmentation of chemosensitivity by the mdr antagonist, verapamil. Thus, coexposure to verapamil enhances the cytotoxicity of vincristine, doxorubicin and VM26 in T98G cells and that of vincristine in LN-229 cells. Chronic exposure of the cells to low concentrations of vincristine and doxorubicin, but not VM26, topotecan or BCNU, moderately enhances the mdr-like phenotype, as assessed by drug expulsion assays. However, chronic exposure to increasing drug concentrations does not significantly alter the sensitivity to the respective drugs. These data are consistent with a constitutive, but not drug-inducible, mdr-like drug resistance in glioma cells in vitro. Immunocytochemical analysis of human malignant gliomas in vivo reveals that Pgp expression is more abundant in endothelial cells within the gliomas, than in the glioma cells proper. Importantly, Pgp expression is unaltered by radiochemotherapy, assessed by comparative immunocytochemistry of glioma specimens obtained serially before and after radiochemotherapy. We conclude that (i) glioma cells exhibit constitutive mdr-like drug resistance that is not significantly altered by chronic drug exposure in vitro; (ii) endothelial cells may play an important role in Pgp-mediated drug resistance of gliomas in vivo; (iii) radiotherapy and repeated chemotherapy cycles do not modulate Pgp expression in human malignant gliomas in vivo; (iv) there is preliminary evidence for a non-Pgp, verapamil-sensitive drug transport activity in glioma cells.
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  • 4
    ISSN: 1432-0533
    Keywords: Key words Stroke ; Prostaglandin ; Inflammation ; Tissue remodeling ; Secondary injury
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cyclooxygenases (COX; prostaglandin endoperoxide H synthases) are key enzymes in the conversion of arachidonic acid into prostanoids which mediate inflammation, immunomodulation, mitogenesis, ovulation, fewer, apoptosis and blood flow. Here, we report COX-1 expression following focal cerebral infarctions (FCI). In healthy control brains, COX-1 was localized by immunohistochemistry to a few endothelial cells, single neurons and rare, evenly distributed brain microglia/macrophages. In infarctioned brains, COX-1+ cells accumulated highly significantly (P 〈 0.0001) in peri-infarctional areas and in the developing necrotic core early after infarction. Here, cell numbers remained persistently elevated up to several months post infarction. Further, clusters of COX-1+ cells were located in perivascular regions related to the Virchow-Robin space. Double-labeling experiments confirmed co-expression of COX-1 by CD68+ microglia/macrophages. Co-expression of the activation antigens HLA-DR, -DP, -DQ (MHC class II) or the macrophage inhibitor factor-related protein MRP-8 (S100A8) by most COX-1+ microglia/macrophages was only seen early after infarction. Thus, COX-1 appeared to be expressed in microglial cells regardless of their activation state. However, the prolonged accumulation of COX-1+ microglia/macrophages restricted to peri-infarctional areas enduring the acute post-ischemic inflammatory response points to a role of COX-1 in tissue remodeling or in the pathophysiology of secondary injury. We have identified localized, accumulated COX-1 expression as a potential pharmacological target following FCI. Therefore we suggest that therapeutic approaches based on selective COX-2 blocking might ¶not be sufficient for suppressing the local synthesis of prostanoids.
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  • 5
    ISSN: 1432-0533
    Keywords: Key words Intracellular signalling ; Ki-67 ; Microglia activation ; Normal brain ; Ischemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human traumatic brain injury (TBI) is ideally suited for investigation of the kinetics of human microglial cell activation as the onset of lesion formation is precisely defined. The present study provides evidence of a distinct delay in macrophage/microglia response following TBI. Eighteen brains of patients who had survived TBI for 1 h to 6 months were analysed by immunohistology. Samples of contusional and non-contusional areas were studied using antibodies directed against antigens of microglia/ macrophages [major histocompatibility complex class II, CD4, interleukin (IL)-16, macrophage-related protein (MRP) 8 and MRP14]. IL-16, a natural ligand to CD4, was expressed constitutively by numerous microglial cells in all cases throughout the brain. CD4 could be detected regularly on perivascular cells. MRP8 and MRP14, which are only expressed on activated macrophages and microglial cells, could be detected only within brains with a survival time of more than 72 h post TBI. In addition, proliferation of microglia detected by MIB-1 was not present until 72 h. This delayed expression of the activation markers MRP8 and MRP14 and the proliferation marker MIB-1 is comparable to experimental closed head injuries but strictly different from acute activation found in ischemic brains.
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  • 6
    ISSN: 1432-0533
    Keywords: Key words Hodgkin’s lymphoma ; Primary central ¶nervous system lymphoma ; Immunosuppression ; Epstein-Barr virus ; Immunoglobulin rearrangement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 66-year-old woman treated for ocular myasthenia gravis with azathioprine for 12 years presented with a left fronto-parietal mass. Histology revealed primary Hodgkin’s lymphoma of the central nervous system with CD30, Epstein-Barr virus (EBV) latent membrane protein and CD20-positive, CD45 (LCA)-negative Reed-Sternberg cells surrounded by T cells. Moreover, EBV-encoded RNA-1 (EBER-1) sequences and a monoclonal rearrangement of the immunoglobulin heavy chain CDR2 locus were detected.
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  • 7
    ISSN: 0942-0940
    Keywords: Keywords: Brain; microcirculation; intravital microscopy.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary ¶ Background. Investigations have shown an increase of leukocyte-endothelium-interaction in a variety of organs following an ischaemic insult. To elucidate the role of leukocyte-endothelium-interaction following global, cerebral ischaemia the present study was performed. Methods. Global, cerebral ischaemia was induced for twenty minutes by four-vessel-occlusion (PULSINELLI). Leukocyte-endothelium-interaction was studied in the cerebral microcirculation using a rat closed cranial window and intravital microscopy. Leukocytes were stained intravenously using rhodamine 6G. Diameters of pial vessels, leukocyte centreline velocity and number of rolling or adhering leukocytes were determined off-line up to 2 h following global cerebral ischaemia. To confirm these results immunohistochemistry of the brain was performed. Findings. Four-vessel-occlusion induced an iso-electric EEG, venular stasis and minimal rest flow in arterioles. Reperfusion yielded a significant increase of the arteriolar (p〈0.001) and a smaller increase of the venular diameters (p〈0.01). Up to 2 h after ischaemia no significant increase of the number of rolling or adhering leukocytes was measured which was confirmed by immunohistochemistry. Interpretation. In contrast to other studies, in particular regarding focal cerebral ischaemia, an increase of leukocyte-endothelium-interaction in rat brain following 20 min of global cerebral ischaemia was not observed despite histological evidence of ischaemic damage. Thus in our model leukocytes seem not to contribute to the brain damage following global ischaemia.
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  • 8
    ISSN: 1573-7373
    Keywords: spinal glioblastoma ; immunohistochemistry ; cerebral metastasis ; meningeosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 31-year old female underwent subtotal resection of a spinal glioblastoma multiforme (GBM) at level D 10/11 in June 1997. Immunohistochemistry revealed increased MIB-1 labeling index and accumulation of p53 protein. Routine MRI in February 1998 showed multiple tumors of the lumbar spinal cord. At open biopsy, diffuse infiltration of multiple radices was seen. Histologically and immunohistochemically, the tumor was similar to the primary. In May 1998, MRI revealed multiple intracranial metastases and meningeal involvement. The patient died in June 1998, 13 months after the onset of symptoms. The lifes of patients with spinal gliomas are not endangered by direct compression of the brain stem, and systemic metastases are extremely uncommon with gliomas. Yet, survival times in the reported case and in the literature are not better than with cerebral localization. Analysis of the present case and a survey of the literature indicate that CSF involvement and consecutive intracranial seeding determine the prognosis of patients with spinal GBM. Thus, regular monitoring of CSF-cytology and/or spinal MRI appear to be advisable in spinal GBM.
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  • 9
    ISSN: 1573-7373
    Keywords: Glioblastoma multiforme ; gene amplification ; oncogene mdm2 ; p53 mutations ; prognostic value ; tumorigenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Malignant gliomas are the most frequent primary brain tumors. Recent studies defined several genetic markers, which might characterize molecular-biological subsets of glioblastomas with probably prognostic implications. To elucidate the involvement of murine-double-minute (mdm)2 gene amplifications and mutations of the tumor suppressor gene p53 in the tumorigenesis of malignant gliomas we analyzed a series of 75 glioblastomas. The p53 mutations occur in one-third of glioblastomas, mdm2 amplifications were found in 13% of cases. Our analysis revealed a hot spot in the p53 gene locus in codon 156, the same point mutation was detected in 4 tumor samples. None of the mdm2 amplified tumors had p53 mutations, supporting the hypothesis, that mdm2 amplifications are alternative mechanisms for p53 inactivation. Patients with p53 mutated tumors were significantly younger characterized by a mean age of 44 years. Additionally association with longer overall survival could be detected for this subgroup of patients. In our study, survival estimation revealed a significant correlation of mdm2 gene amplification with shorter survival time, and support the hypothesis, that mdm2 oncogene activation appears to occur late in tumor progression and may be characteristic as negative prognostic marker.
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  • 10
    ISSN: 1432-1459
    Keywords: Key words Oligodendroglioma ; Oligoastrocytoma ; PCV ; Chemotherapy ; Brain tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Oligodendroglial tumors have been identified as a subgroup of glial neoplasms with a distinctly better response to chemotherapy and overall survival than purely astrocytic gliomas. Here we report our experience with adjuvant postirradiation and preirradiation chemotherapy using procarbazine, lomustine, and vincristine (PCV) in 27 patients with WHO grade II or III oligodendroglioma or oligoastrocytoma. The efficacy of chemotherapy was assessed according to the Macdonald response criteria (complete response, CR; partial response, PR; stable disease, SD; progressive disease, PD) and progression-free survival intervals by computed tomography or magnetic resonance imaging. First, we confirm that PCV salvage therapy for patients progressing after radiotherapy is highly effective (n = 11, 1 CR, 5 PR, 5 SD; median progression-free survival has not yet been reached, but is longer than 18 months). Second, 3 patients who received radiotherapy plus PCV as first-line therapy achieved CR and 2 achieved SD, and all 5 are progression-free with a median follow-up of 12 months. Third, given these encouraging results, 11 patients received postoperative preirradiation PCV chemotherapy and were given radiotherapy only upon progression. Preirradiation PCV chemotherapy was also effective (2 CR, 3 PR, 6 SD; median progression-free survival has not been yet reached, but is longer than 14 months). Patients with anaplastic oligoastrocytomas were as likely to respond to PCV chemotherapy, as were patients with anaplastic oligodendroglioma. Three patients who had previously responded to PCV were successfully treated with a second course of PCV upon recurrence. PCV chemotherapy was also effective in patients with leptomeningeal spread of oligodendrogliomas. A randomized prospective trial is required to compare the effectiveness and neurotoxicity of first-line PCV chemotherapy followed by radiotherapy to the traditional reverse sequence.
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