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Objective: Motor-evoked potentials (MEPs) after navigated transcranial magnetic stimulation (nTMS) are mirroring the status of the complete human motor system, far beyond corticospinal integrity. Classic time domain features of MEPs (e.g. peak-to-peak amplitudes and onset latencies) exert a high inter-subject[for full text, please go to the a.m. URL], 72. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgie

Objective: There is an increasing interest in preoperative diffusion tensor imaging fiber tracking (DTI-FT) to preserve function during operations in motor eloquent brain regions. However, DTI tractography is challenged by inherent presumptions (e.g. fractional anisotropy, angulation, fiber length thresholds,[for full text, please go to the a.m. URL], 69. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Mexikanischen und Kolumbianischen Gesellschaft für Neurochirurgie

Objective: The combined use of intraoperative high-field MRI (iMRI) and electrophysiological monitoring (IOM) is often not applied on a routine basis due to concerns on possible side-effects. This is mainly based on sorrow to leave the skin-electrodes in-situ for intraoperative scanning, as burnings[for full text, please go to the a.m. URL], 68. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 7. Joint Meeting mit der Society of British Neurological Surgeons (SBNS)

OECD Guidance Document 34 will be briefly recapitulated in context of special requirements for validation of alternative methods to predict inhalative toxicity. Selection of promising endpoints, standardization, optimization, assessment of variability within and between laboratories, and over time, as well as the development of a prediction model (PM) can be performed according to GD 34. However, final testing under blind conditions is often hampered by necessary analytics. Moreover, technically challenging analytics may have to be shared between labs in a rotating principle. Since each in vitro exposure experiment only provides one data point of a concentration-response, the number of test items employed has to be significantly lower than in other validation studies. We are reporting about a BMBF-funded study in four laboratories aiming at prevalidation of a methodology exposing human lung epithelial cells (A549) with toxic gases at the air/liquid interface. Using four reference gases in phase1 as a training set, both endpoints (cell viability and Comet genotoxicity) showed promising robustness; and a linear prediction model for acute in vivo toxicity could be developed. In phase2, the data set was enlarged by six gases (one overlap), and both, reproducibility and the PM of the training set could be independently confirmed.

Objective: Closed spinal dysraphism warrants primary or secondary surgical intervention. Surgery nowadays is expected to cause no neurological deterioration, regardless of the existence or absence of pre-operative deficits. Extended intraoperative monitoring (eIOM) is often used to reduce the risk of[for full text, please go to the a.m. URL], 65. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)

In acute inhalation toxicity studies, animals inhale substances at given concentrations. Without additional information, it is difficult to estimate the appropriate starting concentration for in vivo inhalation studies. The goal of this BMBF funded project was the standardization and pre-validation of precision cut lung slices (PCLS) as a suitable ex vivo alternative approach to reduce animal numbers used in inhalation toxicology. The project was conducted in three independent laboratories (Fraunhofer ITEM, BASF SE, RWTH Aachen). BfR provided support in biostatistics. In all participating laboratories, rat PCLS were prepared and exposed to 20 substances under standard submerged culture conditions for 1 hour. Toxicity was assessed by measurement of released lactate dehydrogenase (LDH assay) and mitochondrial activity (WST-1 assay) after 23 hours post-incubation. In addition, protein content and IL-1 were measured. For all endpoints a sigmoid dose-response model was fitted to the data and IC50 values were calculated. This study shows the final results for all 20 chemicals. More than 900 dose-response curves were fitted and analysed. Log10[IC50 (M)] obtained for all assay endpoints showed best intra-laboratory consistency for the data obtained by WST-1 and BCA assays. While WST-1 and LDH indicated toxic effects for majority of the substances, only few of the substances induced increase in IL-1. The reproducibility within the participating laboratories appeared to have acceptably low between-laboratory variations for WST-1 and BCA assay. The results show (i) that the test protocol used in this study is adequately transferable for practical use and (ii) that the tissue model using the WST-1 endpoint is reliable. Binary prediction model showed promising results.