Dirk Winkler

Prof. Dr. Dirk Winkler


Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 January 2003 in Neurological Research
Verified
Journal Article
Closed access
CTChristos Trantakis
Christos Trantakis
MTMarc Tittgemeyer
Marc Tittgemeyer
JSJens-Peter Schneider
Jens-Peter Schneider
DLDirk Lindner
Dirk Lindner
DWDirk Winkler
Dirk Winkler
JMJürgen Meixensberger
Jürgen Meixensberger
The object of the paper is to investigate intra-operative brainshift and its relation to the extent of tumor removal. Repeated T1w 3D datasets were acquired at different time points intra-operatively (T0; T1; T2...Tx) using a vertical open 0.5T MR scanner in six patients with intracranial tumor. An offline analysis with initial linear registration, intensity adjustment and finally nonlinear registration of the first versus subsequent time points (T0/T1; T0/T2...To/Tx) was performed, yielding a 3D displacement vector field that describes the brainshift. Brainshift was analysed qualitatively and quantitatively. A semi-automatic segmentation technique was used for calculation of the tumor size and the size of tumor remnants. Semi-automatic segmentation was reliable in all but two cases. Segmentation was difficult and unreliable in astrocytomas grade II. The shift basically followed gravity. The major shift reached levels up to 25 mm. Significant shift was observed at the first time point (T0). Intra-operative brainshift can be analysed qualitatively and also captured quantitatively. Neuronavigation that is based on pre-operatively acquired datasets is associated with a significant risk of surgical morbidity at a very early time point. Parallelisation on a workstation cluster may reduce computation time so that information about the displacement can facilitate updated navigation

12 December 2022 in Molecular Biomedicine
Verified
Journal Article
Open access
PDF file
TSTirosh Shapira
Tirosh Shapira
SVSelvarani Vimalanathan
Selvarani Vimalanathan
CRCeline Rens
Celine Rens
VPVirginia Pichler
Virginia Pichler
SPSandra Peña-Díaz
Sandra Peña-Díaz
YAYossef Av-Gay
Yossef Av-Gay
GSK3β has been proposed to have an essential role in Coronaviridae infections. Screening of a targeted library of GSK3β inhibitors against both SARS-CoV-2 and HCoV-229E to identify broad-spectrum anti-Coronaviridae inhibitors resulted in the identification of a high proportion of active compounds with low toxicity to host cells. A selected lead compound, T-1686568, showed low micromolar, dose-dependent activity against SARS-CoV-2 and HCoV-229E. T-1686568 showed efficacy in viral-infected cultured cells and primary 2D organoids. T-1686568 also inhibited SARS-CoV-2 variants of concern Delta and Omicron. Importantly, while inhibition by T-1686568 resulted in the overall reduction of viral load and protein translation, GSK3β inhibition resulted in cellular accumulation of the nucleocapsid protein relative to the spike protein. Following identification of potential phosphorylation sites of Coronaviridae nucleocapsid, protein kinase substrate profiling assays combined with Western blotting analysis of nine host kinases showed that the SARS-CoV-2 nucleocapsid could be phosphorylated by GSK3β and PKCa. GSK3β phosphorylated SARS-CoV-2 nucleocapsid on the S180/S184, S190/S194 and T198 phospho-sites, following previous priming in the adjacent S188, T198 and S206, respectively. Such inhibition presents a compelling target for broad-spectrum anti-Coronaviridae compound development, and underlies the mechanism of action of GSK3β host-directed therapy against this class of obligate intracellular pathogens.

1 January 2015 in International Journal of Surgery Case Reports
Verified
Journal Article
Open access
NHNiels Hammer
Niels Hammer
CKChristian Kühne
Christian Kühne
JMJürgen Meixensberger
Jürgen Meixensberger
BHBernd Hänsel
Bernd Hänsel
DWDirk Winkler
Dirk Winkler
Introduction: Takotsubo cardiomyopathy is an apical ballooning syndrome, which can be triggered by stress. Only few case reports describe the onset of Takotsubo as a complication of neurosurgery procedures. Clinical presentation: A case of a 53 year-old female with a spinal neurinoma and surgery-associated Takotsubo cardiomyopathy is demonstrated. The patient developed typical signs of a myocardial infarction with circulation depression and ST elevation, but normal cardiac enzymes at the end of surgery. Cardiac catheterization and levocardiography confirmed the absence of any critical coronary disease but the presence of a typical apical ballooning and midventricular hypokinesis. The patient recovered completely under supportive conservative and cardiological therapy, showing regular left ventricular pump function. Conclusion: Interventions in neurosurgery and perioperative care should be kept as stress free as possible. Due to the possibility of neurogenic mechanisms related to cardiomyopathy, Takotsubo cardiomyopathy as an entity of stress-induced complications should be taken into consideration. Highlights:

6 October 2023 in 3D Printing in Medicine
Verified
Journal Article
Open access
PDF file
RGRonny Grunert
Ronny Grunert
DWDirk Winkler
Dirk Winkler
FFFranziska Frank
Franziska Frank
RMRobert Moebius
Robert Moebius
FKFabian Kropla
Fabian Kropla
MEMaria Elze
Maria Elze
Background: Restoration of mobility of the elbow after post-traumatic elbow stiffening due to osteophytes is often a problem. Methods: The anatomical structures were segmented within the CT-scan. Afterwards, the Multi Jet Fusion 3D-printing was applied to create the model made of biocompatible and steam-sterilizable plastic. Preoperative simulation of osteophyte resection at the 3D-model was performed as well as the direct comparison with the patient anatomy intraoperatively. Results: The patient-specific was very helpful for the preoperative simulation of the resection of elbow osteophytes. The 3D anatomical representation improved the preoperative plan its implementation. A high degree of fidelity was found between the 3D Printed Anatomical representation and the actual joint pathology. Conclusions: Arthrolysis of complex post-traumatic bony changes is an important indication for the use of 3D models for preoperative planning. Due to the use of 3D printing and software simulation, accurate resection planning is feasible and residual bony stiffening can be avoided. 3D printing models can lead to an improvement in surgical quality.

CSCaroline Sander
Caroline Sander
NDNikolaus von Dercks
Nikolaus von Dercks
MFMichael Karl Fehrenbach
Michael Karl Fehrenbach
TWTim Wende
Tim Wende
SSSebastian Stehr
Sebastian Stehr
FAFelix Arlt
Felix Arlt
The healthcare system has been placed under an enormous burden by the SARS-CoV-2 (COVID-19) pandemic. In addition to the challenge of providing sufficient care for COVID-19 patients, there is also a need to ensure adequate care for non-COVID-19 patients. We investigated neurosurgical care in a university hospital during the pandemic. We examined the second wave of the pandemic from 1 October 2020 to 15 March 2021 in this retrospective single-center study and compared it to a pre-pandemic period from 1 October 2019 to 15 March 2020. Any neurosurgical intervention, along with patient- and treatment-dependent factors, were recorded. We also examined perioperative complications and unplanned readmissions. A statistical comparison of the study groups was performed. We treated 535 patients with a total of 602 neurosurgical surgeries during the pandemic. This compares to 602 patients with 717 surgeries during the pre-pandemic period. There were 67 fewer patients (reduction to 88.87%) admitted and 115 fewer surgeries (reduction to 83.96%) performed, which were essentially highly elective procedures, such as cervical spinal stenosis, intracranial neurinomas, and peripheral nerve lesions. Regarding complication rates and unplanned readmissions, there was no significant difference between the COVID-19 pandemic and the non-pandemic patient group. Operative capacities were slightly reduced to 88% due to the pandemic. Nevertheless, comprehensive emergency and elective care was guaranteed in our university hospital. This speaks for the sufficient resources and high-quality processes that existed even before the pandemic.

30 June 2021 in Brain Sciences
Verified
Journal Article
Open access
PDF file
CFChristian Fiedler
Christian Fiedler
PJPaul-Philipp Jacobs
Paul-Philipp Jacobs
MMMarcel Müller
Marcel Müller
SKSilke Kolbig
Silke Kolbig
RGRonny Grunert
Ronny Grunert
DWDirk Winkler
Dirk Winkler
Localization of features and structures in images is an important task in medical image-processing. Characteristic structures and features are used in diagnostics and surgery planning for spatial adjustments of the volumetric data, including image registration or localization of bone-anchors and fiducials. Since this task is highly recurrent, a fast, reliable and automated approach without human interaction and parameter adjustment is of high interest. In this paper we propose and compare four image processing pipelines, including algorithms for automatic detection and localization of spherical features within 3D MRI data. We developed a convolution based method as well as algorithms based on connected-components labeling and analysis and the circular Hough-transform. A blob detection related approach, analyzing the Hessian determinant, was examined. Furthermore, we introduce a novel spherical MRI-marker design. In combination with the proposed algorithms and pipelines, this allows the detection and spatial localization, including the direction, of fiducials and bone-anchors.