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Oral e-Poster Presentations - Booth 3: Spine 2 (Tumors), September 26, 2023, 4:10 PM - 4:50 PM
Background: Spinal metastasis remains a persistent and oftentimes urgent challenge in the neurosurgical operating room. We aim to understand metastatic spread to the spinal bone on a molecular level in endothelial cells and tumor cells to facilitate improved therapeutic approaches and diagnostics.
Methods: We established a murine syngeneic spinal bone metastasis model. In vivo dissemination was first evaluated using fluorescent beads, followed by murine cancer cell lines (B16, LLC1). We investigated short-term seeding and long-term growth to identify correlations between seeding and tumor formation. EphrinB2-Eph4 interaction has been described as a crucial mediator of spinal bone metastasis. Transient (pharmacological) and permanent (genetical) ephrinB2-Eph4 interventions were performed.
Results: Dissemination of microbeads to distinct spinal segments depended on segment and particle size. Disseminated tumor cells on the contrary showed less frequent arrest in the bone and equal distribution among segments. EphrinB2 intervention changed the dissemination behavior towards the lumbar segment. Interestingly, only transient intervention retained this distribution, permanent ephrinB2 depletion on endothelial cells (efnb2iΔEC) resulted in equal dispersion of metastases. Histological staining revealed a reduction of Endomucin (Emcn) positive structures in combination with a reduction of Type H (Emcn high/CD31 high) endothelial cells in naïve efnb2iΔEC animals. In tumor tissue, these Type H endothelial cells were unaffected. However, an increase in CD31-expressing endothelial cells was observed under endothelial ephrinB2 depletion. These CD31-expressing endothelial cells have been recently described as Type E (Emcn low/CD31 high) and implicated in angiogenesis and osteogenesis.
Conclusions: We here describe a subpopulation of endothelial cells in efnb2iΔEC mice that seems to resemble pro-angiogenic and possibly pro-adhesive type E endothelial cells. Based on these finding we propose a compensatory pro-angiogenic mechanism in efnb2iΔEC mice that is highjacking pre-existing developmental pathways, which is critical for late-stage spinal metastatic growth independent of the initial seeding and extravasation of metastatic cells.
Oral e-Poster Presentations - Booth 2: Neuro-Oncology C (Imaging&Monitoring), September 27, 2023, 1:00 PM - 2:30 PM
Background: Repetitive TMS (rTMS) can be used to non-invasively map cortical language areas. Commonly, frequencies of 5-10 Hz are used to induce speech errors. We could recently show that frequencies of 30 and 50 Hz are advantageous to achieve higher reliability. However, high-frequent rTMS applied over perisylvian regions still suffer from limited tolerability. Using short-train or paired-pulse TMS (pp-TMS) might offer a good alternative to rTMS to interfere with speech production. In this study, we, therefore, compared 30 Hz rTMS to pp-TMS aiming at improved language mapping.
Methods: 13 healthy, right-handed subjects (f=6, 25-41 years) were investigated using two different rTMS protocols: (i) 30 Hz rTMS and (ii) pp-TMS. TMS protocols were applied in a pseudo-randomized order during a picture naming task (picture-to-trigger interval: 0 ms) over cortical language areas. In a subsequent study, we compared pp-TMS also to short trains of three TMS pulses and repetitive paired pulse TMS. Language errors were post-hoc analysed by two independent raters and were assigned to eight different error categories. The level of pain was assessed on a subjective 0-10 numeric rating scale (NRS). Moreover, language error distribution was analysed using a cortical parcellation system.
Results: 30 Hz rTMS evoked a significantly higher number of errors than the pp-protocol, i.e., 18 ± 12 % vs. 10 ± 7 % (p<0.05). However, pp-TMS was significantly better tolerated with a mean NRS of 2.3 ± 1.6 vs. 3.4 ± 1.5 (p<0.05, FDR-corrected). Of note, pp-TMS could induce a higher number of anomias (15 ± 15 %) than repetitive TMS protocols (4 ± 7 %; p<0.1, FDR-corrected), but less dysarthria. The cortical distribution of errors differed between the two protocols. The results of train-of-three TMS were similar to the pp-TMS protocol.
Conclusions: Due to its better tolerability, pp-TMS might offer the possibility to stimulate regions which are particularly prone to direct facial / trigeminal nerve stimulation, e.g., the inferior frontal gyrus. Moreover, pp-TMS seems advantageous for mapping patients who are comparatively susceptible to rTMS side effects and with regard to safety in general.
Introduction: Lumbosacral fixation is a common procedure in primary and revision spine surgery but leads to high biomechanical stress on adjacent segments and the SIJ, resulting in implant failure such as breakage and loosening and pain. This frequently results in further surgery. For patients showing clinical and radiological signs of SIJ affection/arthrosis who fail conservative therapy, transarticular lumbopelvic fusion via the SIJ may be considered. The Bedrock™ technique has been described as a new option for reinforced lumbopelvic fixation, fusing the SIJ with additional triangular titanium implants, thereby reducing biomechanical loads off the S2AI screws. We share our experiences with 19 patients treated with this technique since January 2019.
Materials and Methods: 19 patients suffering from persisting low back pain (LBP) with indication for reinforced lumbopelvic fixation and SIJ fusion were treated with reinforced lumboplevic fixation with S2AI screw and a triangular titanium implant. 14 cases were revisions. All surgeries were carried out by a single surgeon at a orthopedic university hospital. Data was gathered retrospectively.
Results: From 1/2019 - 9/2021 19 patients (11f, 8m) were treated with reinforced lumbopelvic fixation and SIJ fusion with a mean follow up of 18,2 months. Mean age 68 years (range 62-78y). Preop. walking distance was reduced to an average <100 m. Standard treatment involved S2AI screws and triangular titanium implants (SIBone, iFuse 3D™). 14 revision cases split into 5 low grade infections with screw loosening, 3 cases with rod breakage, 5 cases of painful lumbopelvic screw prominence, 7 cases with proximal junctional kyphosis, 2 cases with misplaced implants, 8 cases of poor bone mineral density. 5 patients without prior spine surgery. All patients were treated bilaterally using freehand technique. Average implant length was 65 mm. There were no intraoperative or implant associated adverse events (AE) or serious adverse events (SAE). Postoperative imaging demonstrated good implant positioning and function. All patients regained walking ability for distances > 1000 m and were satisfied with the result. All patients reported significant reduction of SIJ pain.
Conclusion: We report results of 19 patients with a reinforced lumbopelvic fixation and fusion by S2AI screws augmented by one parallelly placed triangular titanium implant fusing the SIJ bilaterally with a mean follow-up of 18.2 months. Intra- and postoperatively we experienced no implant associated adverse event. Patients regained significant walking ability and significant reduction of SIJ pain. Radiologically no signs of implant loosening or failure were detected at the end of follow-up. Our results demonstrate a safe and efficacious surgical technique for reinforced lumbopelvic fixation with fusion of SIJ with significant improvement of the health care related quality of life. Further studies need to be conducted in order to obtain additional evidence.
This article summarizes some of the current theoretical developments and the experimental status of hypernuclei in relativistic heavy-ion collisions and elementary collisions. In particular, the most recent results of hyperhydrogen of mass A = 3 and 4 are discussed. The highlight at SQM2022 in this perspective was the discovery of the anti-hyperhydrogen-4 by the STAR Collaboration, in a large data set consisting of different collision systems. Furthermore, the production yields of hyperhydrogen-4 and hyperhelium-4 from the STAR Collaboration can be described nicely by the thermal model when the excited states of these hypernuclei are taken into account. In contrast, the production measurements in small systems (pp and p–Pb) from the ALICE Collaboration tends to favour the coalescence model over the thermal description. New measurements from STAR, ALICE and HADES Collaborations of the properties, e.g. lifetime, of A = 3 and 4 hypernuclei give similar results of these properties. Also the anti-hyperhydrogen-4 lifetime is in rather good agreement with previous measurements. Interestingly, the new STAR measurement on the R3 value, that is connected to the branching ratio, points to a Λ separation energy that is below 100 keV but definitely consistent with the value of 130 keV assumed since the 70s.
We show examples of the impact of the Maxwellian averaged capture cross sections determined at n_TOF over the past 20 years on AGB stellar nucleosynthesis models. In particular, we developed an automated procedure to derive MACSs from evaluated data libraries, which are subsequently used as input to stellar models computed by means of the FuNS code. In this contribution, we present a number of s-process abundances obtained using different data libraries as input to stellar models, with a focus on the role of n_TOF data.
Asymptotic giant branch (AGB) stars are responsible for the production of the main component of the solar s-process distribution. Despite enormous progress in the theoretical modeling of these objects over the last few decades, many uncertainties remain. The still-unknown mechanism leading to the production of 13C neutron source is one example. The nucleosynthetic signature of AGB stars can be examined in a number of stellar sources, from spectroscopic observations of intrinsic and extrinsic stars to the heavy-element isotopic composition of presolar grains found in meteorites. The wealth of available observational data allows for constraining the processes occurring in AGB interiors. In this view, we discuss recent results from new AGB models including the effects of mixing triggered by magnetic fields, and show comparisons of the related s-process nucleosynthesis with available observations.
In this work, inhomogeneous chiral phases are studied in a variety of Four-Fermion and Yukawa models in 2+1 dimensions at zero and non-zero temperature and chemical potentials. Employing the mean-field approximation, we do not find indications for an inhomogeneous phase in any of the studied models. We show that the homogeneous phases are stable against inhomogeneous perturbations. At zero temperature, full analytic results are presented.
In this work we study the 3+1-dimensional Nambu-Jona-Lasinio (NJL) model in the mean field-approximation. We carry out calculations using five different regularization schemes (two continuum and three lattice regularization schemes) with particular focus on inhomogeneous phases and condensates. The regularization schemes lead to drastically different inhomogeneous regions. We provide evidence that inhomogeneous condensates appear for all regularization schemes almost exclusively at values of the chemical potential and with wave numbers, which are of the order of or even larger than the corresponding regulators. This can be interpreted as indication that inhomogeneous phases in the 3+1-dimensional NJL model are rather artifacts of the regularization and not a consequence of the NJL Lagrangian and its symmetries.
Lattice QCD and functional methods are making significant progress in constraining the QCD phase diagram. As an important milestone, the chiral phase transition with massless u, d-quarks at zero density is now understood to be of second order for all strange quark masses, and a smooth crossover as soon as mu,d, ≠ 0. Together with information on fluctuations and refined reweighted simulations, this bounds a possible critical point to be at µB/T ≲3. On the other hand, an approximately chiral-spin symmetric temperature window has been discovered above the chiral crossover, Tch<T ≳3Tch, with distinct correlator multiplet patterns and a pion spectral function suggesting resonance-like degrees of freedom, which dissolve graduallly with temperature.
Prediction for hyper nuclei multiplicities from GSI to LHC energies from the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model combined with a final state coalescence approach is presented and compared to the thermal model. The influence of the coalescence radius on the collision energy and centrality dependence of the Λ3H/ΛΛ3H/Λ ratio is discussed.