Ulrich Bogdahn

Bio: Ulrich Bogdahn is an academic researcher from University of Regensburg. The author has contributed to research in topics: Neural stem cell & Neurogenesis. The author has an hindex of 67, co-authored 344 publications receiving 32279 citations. Previous affiliations of Ulrich Bogdahn include Hoffmann-La Roche & Volkswagen Foundation.

Oligodendrogenesis of adult neural progenitors: differential effects of ciliary neurotrophic factor and mesenchymal stem cell derived factors.

Abstract: The oligodendrogenic program of progenitor cells in the adult CNS follows a sequential process of progenitor proliferation, fate choice, determination, differentiation, maturation and survival. Previously, we described a soluble activity derived from mesenchymal stem cells that induces oligodendrogenesis in adult neural progenitor cells. Here, we hypothesized that ciliary neurotrophic factor might be a candidate for this activity, since (i) it is expressed by mesenchymal stem cells and (ii) it can promote oligodendrogenesis during development. Along the course of the study, we found differential effects by ciliary neurotrophic factor and by the mesenchymal stem cells-derived activity on neural progenitors. While the mesenchymal stem cells-derived activity induced oligodendrogenesis at the expense of astrogenesis and promoted oligodendroglial differentiation/maturation, the effect of ciliary neurotrophic factor was restricted to the latter one. This was reflected at the levels of the cell fate determinants Olig1, Olig2, Id2, and the oligodendroglia-maturation transcription factor GTX/Nkx6.2. Finally, experiments using blocking antibodies excluded ciliary neurotrophic factor to be the mesenchymal stem cell-derived oligodendroglial activity. In summary, this work provides evidence for differential effects of ciliary neurotrophic factor and mesenchymal stem cells-derived activity on oligodendrogenesis of adult neural progenitor cells.

Prehospital stroke diagnostics based on neurological examination and transcranial ultrasound.

Abstract: Transcranial color-coded sonography (TCCS) has proved to be a fast and reliable tool for the detection of middle cerebral artery (MCA) occlusions in a hospital setting. In this feasibility study on prehospital sonography, our aim was to investigate the accuracy of TCCS for neurovascular emergency diagnostics when performed in a prehospital setting using mobile ultrasound equipment as part of a neurological examination. Following a ‘911 stroke code’ call, stroke neurologists experienced in TCCS rendezvoused with the paramedic team. In patients with suspected stroke, TCCS examination including ultrasound contrast agents was performed. Results were compared with neurovascular imaging (CTA, MRA) and the final discharge diagnosis from standard patient-centered stroke care. We enrolled ‘232 stroke code’ patients with follow-up data available in 102 patients with complete TCCS examination. A diagnosis of ischemic stroke was made in 73 cases; 29 patients were identified as ‘stroke mimics’. MCA occlusion was diagnosed in ten patients, while internal carotid artery (ICA) occlusion/high-grade stenosis leading to reversal of anterior cerebral artery flow was diagnosed in four patients. The initial working diagnosis ‘any stroke’ showed a sensitivity of 94% and a specificity of 48%. ‘Major MCA or ICA stroke’ diagnosed by mobile ultrasound showed an overall sensitivity of 78% and specificity of 98%. The study demonstrates the feasibility and high diagnostic accuracy of emergency transcranial ultrasound assessment combined with neurological examinations for major ischemic stroke. Future combination with telemedical support, point-of-care analysis of blood serum markers, and probability algorithms of prehospital stroke diagnosis including ultrasound may help to speed up stroke treatment.

Chemosensitivity of malignant human brain tumors. Preliminary results.

Abstract: Tumor cell proliferation and morphological changes in tumor cells under the influence of different cytostatic agents were measured in an in vitro assay to determine chemosensitivity of human malignant brain tumors. Aliquots of 2 to 5 × 104 cells of a tumor cell suspension (prepared from biopsy specimen by mechanical and enzymatic disintegration) were incubated for 72 hr in the presence of different cytostatic agents. After another nine days of incubation in fresh medium, cell proliferation was calculated by incorporation of 14C-leucine and 3H-uridine and measurement in a liquid scintillation counter. Morphological changes in tumor cells were evaluated in Labtek tissue culture slides cultured under identical conditions. All drugs were tested in pharmacologically achievable concentrations. In vitro BCNU-sensitivity of 7/17 patients correlated with a postoperative recurrence free interval of 15.1 months, in vitro BCNU-resistance of 10/ 17 patients correlated with a postoperative recurrence free interval of 6.38 months (p < 0.001). Tumors of lower grades of malignancy (astrocytoma III, malignant ependymoma, medulloblastoma) in our series have a statistically significant higher median BCNU-sensitivity (63.5%, p < 0.05) and are sensitive to more drugs (3.6 drugs, median out of six selected drugs, p < 0.01) than tumors of higher grades of malignancy (astrocytoma IV, glioblastoma multiforme; 29.54% BCNU-sensitivity, 1.4 effective drugs). In our series differences of BCNU-tumor sensitivity and number of effective drugs were not statistically significant if related to age and sex of tumor bearing patients. We think this assay provides the opportunity to test a large number of drugs in a very short period of time. Results may indicate alternative drug regimen for those patients resistant to conventional chemotherapy.

A nuclear magnetic resonance biomarker for neural progenitor cells: is it all neurogenesis?

Abstract: In vivo visualization of endogenous neural progenitor cells (NPCs) is crucial to advance stem cell research and will be essential to ensure the safety and efficacy of neurogenesis-based therapies. Magnetic resonance spectroscopic imaging (i.e., spatially resolved spectroscopy in vivo) is a highly promising technique by which to investigate endogenous neurogenesis noninvasively. A distinct feature in nuclear magnetic resonance spectra (i.e., a lipid signal at 1.28 ppm) was recently attributed specifically to NPCs in vitro and to neurogenic regions in vivo. Here, we demonstrate that although this 1.28-ppm biomarker is present in NPC cultures, it is not specific for the latter. The 1.28-ppm marker was also evident in mesenchymal stem cells and in non-stem cell lines. Moreover, it was absent in freshly isolated NPCs but appeared under conditions favoring growth arrest or apoptosis; it is initiated by induction of apoptosis and correlates with the appearance of mobile lipid droplets. Thus, although the 1.28-ppm signal cannot be considered as a specific biomarker for NPCs, it might still serve as a sensor for processes that are tightly associated with neurogenesis and NPCs in vivo, such as apoptosis or stem cell quiescence. However, this requires further experimental evidence. The present work clearly urges the identification of additional biomarkers for NPCs and for neurogenesis.

Guidelines for the Early Management of Patients With Acute Ischemic Stroke A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

Abstract: Background and Purpose—The authors present an overview of the current evidence and management recommendations for evaluation and treatment of adults with acute ischemic stroke. The intended audienc...

Headache Classification Committee of the International Headache Society (IHS) The International Classification of Headache Disorders, 3rd edition

Abstract: The 3rd edition of the International Classification of Headache Disorders (ICHD-3) may be reproduced freely for scientific, educational or clinical uses by institutions, societies or individuals. Otherwise, copyright belongs exclusively to the International Headache Society. Reproduction of any part or parts in any manner for commercial uses requires the Society’s permission, which will be granted on payment of a fee. Please contact the publisher at the address below. International Headache Society 2013–2018. Applications for copyright permissions should be submitted to Sage Publications Ltd, 1 Oliver’s Yard, 55 City Road, London EC1Y 1SP, United Kingdom (tel: þ44 (0) 207 324 8500; fax: þ44 (0) 207 324 8600; permissions@sagepub.co.uk) (www.uk.sagepub.com). Translations

Effects of radiotherapy with concomitant and adjuvant temozolomide versus radiotherapy alone on survival in glioblastoma in a randomised phase III study: 5-year analysis of the EORTC-NCIC trial

Abstract: BACKGROUND: In 2004, a randomised phase III trial by the European Organisation for Research and Treatment of Cancer (EORTC) and National Cancer Institute of Canada Clinical Trials Group (NCIC) reported improved median and 2-year survival for patients with glioblastoma treated with concomitant and adjuvant temozolomide and radiotherapy. We report the final results with a median follow-up of more than 5 years. METHODS: Adult patients with newly diagnosed glioblastoma were randomly assigned to receive either standard radiotherapy or identical radiotherapy with concomitant temozolomide followed by up to six cycles of adjuvant temozolomide. The methylation status of the methyl-guanine methyl transferase gene, MGMT, was determined retrospectively from the tumour tissue of 206 patients. The primary endpoint was overall survival. Analyses were by intention to treat. This trial is registered with Clinicaltrials.gov, number NCT00006353. FINDINGS: Between Aug 17, 2000, and March 22, 2002, 573 patients were assigned to treatment. 278 (97%) of 286 patients in the radiotherapy alone group and 254 (89%) of 287 in the combined-treatment group died during 5 years of follow-up. Overall survival was 27.2% (95% CI 22.2-32.5) at 2 years, 16.0% (12.0-20.6) at 3 years, 12.1% (8.5-16.4) at 4 years, and 9.8% (6.4-14.0) at 5 years with temozolomide, versus 10.9% (7.6-14.8), 4.4% (2.4-7.2), 3.0% (1.4-5.7), and 1.9% (0.6-4.4) with radiotherapy alone (hazard ratio 0.6, 95% CI 0.5-0.7; p<0.0001). A benefit of combined therapy was recorded in all clinical prognostic subgroups, including patients aged 60-70 years. Methylation of the MGMT promoter was the strongest predictor for outcome and benefit from temozolomide chemotherapy. INTERPRETATION: Benefits of adjuvant temozolomide with radiotherapy lasted throughout 5 years of follow-up. A few patients in favourable prognostic categories survive longer than 5 years. MGMT methylation status identifies patients most likely to benefit from the addition of temozolomide. FUNDING: EORTC, NCIC, Nelia and Amadeo Barletta Foundation, Schering-Plough.

MGMT Gene Silencing and Benefit from Temozolomide in Glioblastoma

Abstract: background Epigenetic silencing of the MGMT (O 6 -methylguanine–DNA methyltransferase) DNArepair gene by promoter methylation compromises DNA repair and has been associated with longer survival in patients with glioblastoma who receive alkylating agents. methods We tested the relationship between MGMT silencing in the tumor and the survival of patients who were enrolled in a randomized trial comparing radiotherapy alone with radiotherapy combined with concomitant and adjuvant treatment with temozolomide. The methylation status of the MGMT promoter was determined by methylation-specific polymerase-chain-reaction analysis. results The MGMT promoter was methylated in 45 percent of 206 assessable cases. Irrespective of treatment, MGMT promoter methylation was an independent favorable prognostic factor (P<0.001 by the log-rank test; hazard ratio, 0.45; 95 percent confidence interval, 0.32 to 0.61). Among patients whose tumor contained a methylated MGMT promoter, a survival benefit was observed in patients treated with temozolomide and radiotherapy; their median survival was 21.7 months (95 percent confidence interval, 17.4 to 30.4), as compared with 15.3 months (95 percent confidence interval, 13.0 to 20.9) among those who were assigned to only radiotherapy (P=0.007 by the log-rank test). In the absence of methylation of the MGMT promoter, there was a smaller and statistically insignificant difference in survival between the treatment groups. conclusions Patients with glioblastoma containing a methylated MGMT promoter benefited from temozolomide, whereas those who did not have a methylated MGMT promoter did not have such a benefit.