@article{HenkeNandigamaErguen2020,
  author    = {Henke, Erik and Nandigama, Rajender and Erg{\"u}n, S{\"u}leyman},
  title     = {Extracellular matrix in the tumor microenvironment and its impact on cancer therapy},
  series = {Frontiers in Molecular Biosciences},
  volume    = {6},
  journal   = {Frontiers in Molecular Biosciences},
  number    = {160},
  issn      = {2296-889X},
  doi       = {10.3389/fmolb.2019.00160},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199341},
  year      = {2020},
  abstract  = {Solid tumors are complex organ-like structures that consist not only of tumor cells but also of vasculature, extracellular matrix (ECM), stromal, and immune cells. Often, this tumor microenvironment (TME) comprises the larger part of the overall tumor mass. Like the other components of the TME, the ECM in solid tumors differs significantly from that in normal organs. Intratumoral signaling, transport mechanisms, metabolisms, oxygenation, and immunogenicity are strongly affected if not controlled by the ECM. Exerting this regulatory control, the ECM does not only influence malignancy and growth of the tumor but also its response toward therapy. Understanding the particularities of the ECM in solid tumor is necessary to develop approaches to interfere with its negative effect. In this review, we will also highlight the current understanding of the physical, cellular, and molecular mechanisms by which the pathological tumor ECM affects the efficiency of radio-, chemo-, and immunotherapy. Finally, we will discuss the various strategies to target and modify the tumor ECM and how they could be utilized to improve response to therapy.},
  language  = {en}
}
@article{GrunzWenigKunzetal.2020,
  author    = {Grunz, Jan-Peter and Wenig, Andreas Max and Kunz, Andreas Steven and Veyhl-Wichmann, Maike and Schmitt, Rainer and Gietzen, Carsten Herbert and Pennig, Lenhard and Herz, Stefan and Erg{\"u}n, S{\"u}leyman and Bley, Thorsten Alexander and Gassenmaier, Tobias},
  title     = {3D cone-beam CT with a twin robotic x-ray system in elbow imaging: comparison of image quality to high-resolution multidetector CT},
  series = {European Radiology Experimental},
  volume    = {4},
  journal   = {European Radiology Experimental},
  doi       = {10.1186/s41747-020-00177-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229877},
  year      = {2020},
  abstract  = {Background Elbow imaging is challenging with conventional multidetector computed tomography (MDCT), while cone-beam CT (CBCT) provides superior options. We compared intra-individually CBCT versus MDCT image quality in cadaveric elbows. Methods A twin robotic x-ray system with new CBCT mode and a high-resolution clinical MDCT were compared in 16 cadaveric elbows. Both systems were operated with a dedicated low-dose (LD) protocol (equivalent volume CT dose index [CTDI\(_{vol(16 cm)}\)] = 3.3 mGy) and a regular clinical scan dose (RD) protocol (CTDI\(_{vol(16 cm)}\) = 13.8 mGy). Image quality was evaluated by two radiologists (R1 and R2) on a seven-point Likert scale, and estimation of signal intensity in cancellous bone was conducted. Wilcoxon signed-rank tests and intraclass correlation coefficient (ICC) statistics were used. Results The CBCT prototype provided superior subjective image quality compared to MDCT scans (for RD, p ≤ 0.004; for LD, p ≤ 0.001). Image quality was rated very good or excellent in 100\% of the cases by both readers for RD CBCT, 100\% (R1) and 93.8\% (R2) for LD CBCT, 62.6\% and 43.8\% for RD MDCT, and 0.0\% and 0.0\% for LD MDCT. Single-measure ICC was 0.95 (95\% confidence interval 0.91-0.97; p < 0.001). Software-based assessment supported subjective findings with less "undecided" pixels in CBCT than dose-equivalent MDCT (p < 0.001). No significant difference was found between LD CBCT and RD MDCT. Conclusions In cadaveric elbow studies, the tested cone-beam CT prototype delivered superior image quality compared to high-end multidetector CT and showed a potential for considerable dose reduction.},
  language  = {en}
}
@article{CapetianMuellerVolkmannetal.2020,
  author    = {Capetian, Philipp and M{\"u}ller, Lorenz and Volkmann, Jens and Heckmann, Manfred and Erg{\"u}n, S{\"u}leyman and Wagner, Nicole},
  title     = {Visualizing the synaptic and cellular ultrastructure in neurons differentiated from human induced neural stem cells - an optimized protocol},
  series = {International Journal of Molecular Sciences},
  volume    = {21},
  journal   = {International Journal of Molecular Sciences},
  number    = {5},
  issn      = {1422-0067},
  doi       = {10.3390/ijms21051708},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-236053},
  year      = {2020},
  abstract  = {The size of the synaptic subcomponents falls below the limits of visible light microscopy. Despite new developments in advanced microscopy techniques, the resolution of transmission electron microscopy (TEM) remains unsurpassed. The requirements of tissue preservation are very high, and human post mortem material often does not offer adequate quality. However, new reprogramming techniques that generate human neurons in vitro provide samples that can easily fulfill these requirements. The objective of this study was to identify the culture technique with the best ultrastructural preservation in combination with the best embedding and contrasting technique for visualizing neuronal elements. Two induced neural stem cell lines derived from healthy control subjects underwent differentiation either adherent on glass coverslips, embedded in a droplet of highly concentrated Matrigel, or as a compact neurosphere. Afterward, they were fixed using a combination of glutaraldehyde (GA) and paraformaldehyde (PFA) followed by three approaches (standard stain, Ruthenium red stain, high contrast en-bloc stain) using different combinations of membrane enhancing and contrasting steps before ultrathin sectioning and imaging by TEM. The compact free-floating neurospheres exhibited the best ultrastructural preservation. High-contrast en-bloc stain offered particularly sharp staining of membrane structures and the highest quality visualization of neuronal structures. In conclusion, compact neurospheres growing under free-floating conditions in combination with a high contrast en-bloc staining protocol, offer the optimal preservation and contrast with a particular focus on visualizing membrane structures as required for analyzing synaptic structures.},
  language  = {en}
}
@article{IUedaWoersdoerferetal.2020,
  author    = {I, Takashi and Ueda, Yuichiro and W{\"o}rsd{\"o}rfer, Philipp and Sumita, Yoshinori and Asahina, Izumi and Erg{\"u}n, S{\"u}leyman},
  title     = {Resident CD34-positive cells contribute to peri-endothelial cells and vascular morphogenesis in salivary gland after irradiation},
  series = {Journal of Neural Transmission},
  volume    = {127},
  journal   = {Journal of Neural Transmission},
  issn      = {0300-9564},
  doi       = {10.1007/s00702-020-02256-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235613},
  pages     = {1467-1479},
  year      = {2020},
  abstract  = {Salivary gland (SG) hypofunction is a common post-radiotherapy complication. Besides the parenchymal damage after irradiation (IR), there are also effects on mesenchymal stem cells (MSCs) which were shown to contribute to regeneration and repair of damaged tissues by differentiating into stromal cell types or releasing vesicles and soluble factors supporting the healing processes. However, there are no adequate reports about their roles during SG damage and regeneration so far. Using an irradiated SG mouse model, we performed certain immunostainings on tissue sections of submandibular glands at different time points after IR. Immunostaining for CD31 revealed that already one day after IR, vascular impairment was induced at the level of capillaries. In addition, the expression of CD44—a marker of acinar cells—diminished gradually after IR and, by 20 weeks, almost disappeared. In contrast, the number of CD34-positive cells significantly increased 4 weeks after IR and some of the CD34-positive cells were found to reside within the adventitia of arteries and veins. Laser confocal microscopic analyses revealed an accumulation of CD34-positive cells within the area of damaged capillaries where they were in close contact to the CD31-positive endothelial cells. At 4 weeks after IR, a fraction of the CD34-positive cells underwent differentiation into α-SMA-positive cells, which suggests that they may contribute to regeneration of smooth muscle cells and/or pericytes covering the small vessels from the outside. In conclusion, SG-resident CD34-positive cells represent a population of progenitors that could contribute to new vessel formation and/or remodeling of the pre-existing vessels after IR and thus, might be an important player during SG tissue healing.},
  language  = {en}
}
@article{WoersdoerferIAsahinaetal.2020,
  author    = {W{\"o}rsd{\"o}rfer, Philipp and I, Takashi and Asahina, Izumi and Sumita, Yoshinori and Erg{\"u}n, S{\"u}leyman},
  title     = {Do not keep it simple: recent advances in the generation of complex organoids},
  series = {Journal of Neural Transmission},
  volume    = {127},
  journal   = {Journal of Neural Transmission},
  issn      = {0300-9564},
  doi       = {10.1007/s00702-020-02198-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235628},
  pages     = {1569-1577},
  year      = {2020},
  abstract  = {3D cell culture models which closely resemble real human tissues are of high interest for disease modelling, drug screening as well as a deeper understanding of human developmental biology. Such structures are termed organoids. Within the last years, several human organoid models were described. These are usually stem cell derived, arise by self-organization, mimic mechanisms of normal tissue development, show typical organ morphogenesis and recapitulate at least some organ specific functions. Many tissues have been reproduced in vitro such as gut, liver, lung, kidney and brain. The resulting entities can be either derived from an adult stem cell population, or generated from pluripotent stem cells using a specific differentiation protocol. However, many organoid models only recapitulate the organs parenchyma but are devoid of stromal components such as blood vessels, connective tissue and inflammatory cells. Recent studies show that the incorporation of endothelial and mesenchymal cells into organoids improved their maturation and might be required to create fully functional micro-tissues, which will allow deeper insights into human embryogenesis as well as disease development and progression. In this review article, we will summarize and discuss recent works trying to incorporate stromal components into organoids, with a special focus on neural organoid models.},
  language  = {en}
}