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6 results on '"Felix Gremse"'

1. An Anatomical Thermal 3D Model in Preclinical Research: Combining CT and Thermal Images

Author

Franziska Schollemann, Carina Barbosa Pereira, Stefanie Rosenhain, Andreas Follmann, Felix Gremse, Fabian Kiessling, Michael Czaplik, and Mauren Abreu de Souza

Subjects
thermal imaging, CT, 3D model, VisualSFM, camera calibration, registration, Chemical technology, TP1-1185
Abstract

Even though animal trials are a controversial topic, they provide knowledge about diseases and the course of infections in a medical context. To refine the detection of abnormalities that can cause pain and stress to the animal as early as possible, new processes must be developed. Due to its noninvasive nature, thermal imaging is increasingly used for severity assessment in animal-based research. Within a multimodal approach, thermal images combined with anatomical information could be used to simulate the inner temperature profile, thereby allowing the detection of deep-seated infections. This paper presents the generation of anatomical thermal 3D models, forming the underlying multimodal model in this simulation. These models combine anatomical 3D information based on computed tomography (CT) data with a registered thermal shell measured with infrared thermography. The process of generating these models consists of data acquisition (both thermal images and CT), camera calibration, image processing methods, and structure from motion (SfM), among others. Anatomical thermal 3D models were successfully generated using three anesthetized mice. Due to the image processing improvement, the process was also realized for areas with few features, which increases the transferability of the process. The result of this multimodal registration in 3D space can be viewed and analyzed within a visualization tool. Individual CT slices can be analyzed axially, sagittally, and coronally with the corresponding superficial skin temperature distribution. This is an important and successfully implemented milestone on the way to simulating the internal temperature profile. Using this temperature profile, deep-seated infections and inflammation can be detected in order to reduce animal suffering.

Published
2021
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2. L-Selectin/CD62L Is a Key Driver of Non-Alcoholic Steatohepatitis in Mice and Men

Author

Hannah K. Drescher, Angela Schippers, Stefanie Rosenhain, Felix Gremse, Laura Bongiovanni, Alain de Bruin, Sreepradha Eswaran, Suchira U. Gallage, Dominik Pfister, Marta Szydlowska, Mathias Heikenwalder, Sabine Weiskirchen, Norbert Wagner, Christian Trautwein, Ralf Weiskirchen, and Daniela C. Kroy

Subjects
non-alcoholic steatohepatitis, NASH, CD62L, L-Selectin, insulin resistance, Cytology, QH573-671
Abstract

CD62L (L-Selectin) dependent lymphocyte infiltration is known to induce inflammatory bowel disease (IBD), while its function in the liver, especially in non-alcoholic steatohepatitis (NASH), remains unclear. We here investigated the functional role of CD62L in NASH in humans as well as in two mouse models of steatohepatitis. Hepatic expression of a soluble form of CD62L (sCD62L) was measured in patients with steatosis and NASH. Furthermore, CD62L−/− mice were fed with a methionine and choline deficient (MCD) diet for 4 weeks or with a high fat diet (HFD) for 24 weeks. Patients with NASH displayed increased serum levels of sCD62L. Hepatic CD62L expression was higher in patients with steatosis and increased dramatically in NASH patients. Interestingly, compared to wild type (WT) mice, MCD and HFD-treated CD62L−/− mice were protected from diet-induced steatohepatitis. This was reflected by less fat accumulation in hepatocytes and a dampened manifestation of the metabolic syndrome with an improved insulin resistance and decreased cholesterol and triglyceride levels. Consistent with ameliorated disease, CD62L−/− animals exhibited an enhanced hepatic infiltration of Treg cells and a strong activation of an anti-oxidative stress response. Those changes finally resulted in less fibrosis in CD62L−/− mice. Additionally, this effect could be reproduced in a therapeutic setting by administrating an anti-CD62L blocking antibody. CD62L expression in humans and mice correlates with disease activity of steatohepatitis. CD62L knockout and anti-CD62L-treated mice are protected from diet-induced steatohepatitis suggesting that CD62L is a promising target for therapeutic interventions in NASH.

Published
2020
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3. Molecular Ultrasound Imaging Depicts the Modulation of Tumor Angiogenesis by Acetylsalicylic Acid

Author

Flurin Mueller-Diesing, Wiltrud Lederle, Anne Rix, Susanne Koletnik, Dennis Doleschel, Maximilian Snelting, Felix Gremse, and Fabian Kiessling

Subjects
Inorganic Chemistry, Organic Chemistry, General Medicine, Physical and Theoretical Chemistry, Molecular Biology, Spectroscopy, Catalysis, Computer Science Applications
Abstract

Acetylsalicylic acid (ASA) is a well-established drug for heart attack and stroke prophylaxis. Furthermore, numerous studies have reported an anti-carcinogenic effect, but its exact mechanism is still unknown. Here, we applied VEGFR-2-targeted molecular ultrasound to explore a potential inhibitory effect of ASA on tumor angiogenesis in vivo. Daily ASA or placebo therapy was performed in a 4T1 tumor mouse model. During therapy, ultrasound scans were performed using nonspecific microbubbles (CEUS) to determine the relative intratumoral blood volume (rBV) and VEGFR-2-targeted microbubbles to assess angiogenesis. Finally, vessel density and VEGFR-2 expression were assessed histologically. CEUS indicated a decreasing rBV in both groups over time. VEGFR-2 expression increased in both groups up to Day 7. Towards Day 11, the binding of VEGFR-2-specific microbubbles further increased in controls, but significantly (p = 0.0015) decreased under ASA therapy (2.24 ± 0.46 au vs. 0.54 ± 0.55 au). Immunofluorescence showed a tendency towards lower vessel density under ASA and confirmed the result of molecular ultrasound. Molecular US demonstrated an inhibitory effect of ASA on VEGFR-2 expression accompanied by a tendency towards lower vessel density. Thus, this study suggests the inhibition of angiogenesis via VEGFR-2 downregulation as one of the anti-tumor effects of ASA.

Published
2023
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4. Effects of Strontium-Doped β-Tricalcium Scaffold on Longitudinal Nuclear Factor-Kappa Beta and Vascular Endothelial Growth Factor Receptor-2 Promoter Activities during Healing in a Murine Critical-Size Bone Defect Model

Author

Philipp Lichte, Sabine Neuß, Felix Gremse, Alexander Slowik, Horst Fischer, Diana Roch, Nisreen Kweider, Frank Hildebrand, Athanassios Fragoulis, Christoph Jan Wruck, Holger Jahr, Hans-Christoph Pape, Tobias Michael Heigl, Thomas Pufe, Christian Bergmann, Michaela Bienert, Nazanin Barahmand Pour, Tolga Taha Sönmez, Stefanie Rosenhain, Yusuke Kubo, Jennifer Vanessa Phi Hock, Mersedeh Tohidnezhad, and University of Zurich

Subjects
Calcium Phosphates, 0301 basic medicine, Bone Regeneration, Angiogenesis, Osteoporosis, 1607 Spectroscopy, 02 engineering and technology, NF-κB, lcsh:Chemistry, Mice, chemistry.chemical_compound, strontium, Promoter Regions, Genetic, lcsh:QH301-705.5, Spectroscopy, Tissue Scaffolds, NF-kappa B, Soft tissue, General Medicine, Femoral fracture, 021001 nanoscience & nanotechnology, Immunohistochemistry, bioluminescence, Computer Science Applications, Resorption, Vascular endothelial growth factor, lipids (amino acids, peptides, and proteins), medicine.symptom, 1606 Physical and Theoretical Chemistry, 0210 nano-technology, musculoskeletal diseases, inorganic chemicals, medicine.medical_specialty, 1503 Catalysis, Mice, Transgenic, 610 Medicine & health, Inflammation, Bone and Bones, Article, Catalysis, Inorganic Chemistry, 03 medical and health sciences, Internal medicine, 1312 Molecular Biology, 1706 Computer Science Applications, medicine, Animals, Physical and Theoretical Chemistry, Molecular Biology, large bone defects, 1604 Inorganic Chemistry, Phosphatidylethanolamines, Organic Chemistry, technology, industry, and agriculture, Kinase insert domain receptor, medicine.disease, Vascular Endothelial Growth Factor Receptor-2, β-tricalcium phosphate, 10021 Department of Trauma Surgery, VEGFR-2, 030104 developmental biology, Endocrinology, chemistry, lcsh:Biology (General), lcsh:QD1-999, Bone Substitutes, human activities, 1605 Organic Chemistry
Abstract

It was hypothesized that strontium (Sr)-doped &beta, tricalcium phosphate (TCP)-based scaffolds have a positive effect on the regeneration of large bone defects (LBD). Readouts in our mice models were nuclear factor-kappa beta (NF-&kappa, B) activity and vascular endothelial growth factor receptor-2 (VEGFR-2) promoter activity during the healing process. A 2-mm critical-size femoral fracture was performed in transgenic NF-&kappa, B- and VEGFR-2-luciferase reporter mice. The fracture was filled with a 3D-printed &beta, TCP scaffold with or without Sr. A bioluminescence in-vivo imaging system was used to sequentially investigate NF-&kappa, B and VEGFR-2 expression for two months. After sacrifice, soft and osseous tissue formation in the fracture sites was histologically examined. NF-&kappa, B activity increased in the &beta, TCP + Sr group in the latter stage (day 40&ndash, 60). VEGFR-2 activity increased in the + Sr group from days 0&ndash, 15 but decreased and showed significantly less activity than the &beta, TCP and non-scaffold groups from days 40&ndash, 60. The new bone formation and soft tissue formation in the + Sr group were significantly higher than in the &beta, TCP group, whereas the percentage of osseous tissue formation in the &beta, TCP group was significantly higher than in the &beta, TCP + Sr group. We analyzed longitudinal VEGFR-2 promoter activity and NF-&kappa, B activity profiles, as respective agents of angiogenesis and inflammation, during LBD healing. The extended inflammation phase and eventually more rapid resorption of scaffold caused by the addition of strontium accelerates temporary bridging of the fracture gaps. This finding has the potential to inform an improved treatment strategy for patients who suffer from osteoporosis.

Published
2020
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5. An Anatomical Thermal 3D Model in Preclinical Research: Combining CT and Thermal Images

Author

Andreas Follmann, Fabian Kiessling, Stefanie Rosenhain, Felix Gremse, Carina Barbosa Pereira, Michael Czaplik, Mauren Abreu de Souza, and Franziska Schollemann

Subjects
Models, Anatomic, 3D model, Computer science, Image processing, Computed tomography, Context (language use), lcsh:Chemical technology, 01 natural sciences, Biochemistry, Article, Analytical Chemistry, 010309 optics, Mice, Motion, 03 medical and health sciences, Imaging, Three-Dimensional, registration, 3D THERMO-SCAN, 0103 physical sciences, Image Processing, Computer-Assisted, thermal imaging, medicine, Animals, Structure from motion, lcsh:TP1-1185, Computer vision, Electrical and Electronic Engineering, Instrumentation, multimodality, 030304 developmental biology, 0303 health sciences, medicine.diagnostic_test, business.industry, Process (computing), Atomic and Molecular Physics, and Optics, image processing, Visualization, SfM, Thermography, VisualSFM, Artificial intelligence, Tomography, X-Ray Computed, camera calibration, business, CT, Camera resectioning
Abstract

Sensors 21(4), 1200 (2021). doi:10.3390/s21041200 special issue: "Special Issue "Sensors and Computer Vision Techniques for 3D Object Modeling" / Dr. Marius Leordeanu, Guest Editor", Published by MDPI, Basel

Published
2021
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6. Trabecular Bone Assessment Using Magnetic-Resonance Imaging: A Pilot Study

Author

Lauren Bohner, Felix Gremse, Norbert Meier, Pedro Tortamano, Johannes Kleinheinz, and Marcel Hanisch

Subjects
Materials science, genetic structures, Swine, Health, Toxicology and Mutagenesis, lcsh:Medicine, Pilot Projects, Article, 030218 nuclear medicine & medical imaging, Scan time, 03 medical and health sciences, Imaging, Three-Dimensional, magnetic-resonance imaging, 0302 clinical medicine, Bone Density, dental implants, Porcine bone, medicine, Animals, Pearson Correlation Test, ddc:610, Voxel size, microCT, medicine.diagnostic_test, lcsh:R, Public Health, Environmental and Occupational Health, Magnetic resonance imaging, X-Ray Microtomography, 030206 dentistry, equipment and supplies, Magnetic Resonance Imaging, Trabecular bone, Cancellous Bone, human activities, Bone volume, Statistical correlation, Biomedical engineering
Abstract

The aim of this study was to assess trabecular bone morphology via magnetic-resonance imaging (MRI) using microcomputed tomography (&micro, CT) as the control group. Porcine bone samples were scanned with T1-weighted turbo spin echo sequence imaging, using TR 25 ms, TE 3.5 ms, FOV 100 &times, 100 &times, 90, voxel size 0.22 &times, 0.22 &times, 0.50 mm, and scan time of 11:18. &micro, CT was used as the control group with 80 kV, 125 mA, and a voxel size of 16 &micro, m. The trabecular bone was segmented on the basis of a reference threshold value and morphological parameters. Bone volume (BV), Bone-volume fraction (BvTv), Bone specific surface (BsBv), trabecular thickness (TbTh), and trabecular separation (TbSp) were evaluated. Paired t-test and Pearson correlation test were performed at p = 0.05. MRI overestimated BV, BvTv, TbTh, and TbSp values. BsBv was the only parameter that was underestimated by MRI. High statistical correlation (r = 0.826, p &lt, 0.05) was found for BV measurements. Within the limitations of this study, MRI overestimated trabecular bone parameters, but with a statistically significant fixed linear offset.

Published
2020
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