TY - JOUR A1 - Luetkens, Karsten Sebastian A1 - Grunz, Jan-Peter A1 - Kunz, Andreas Steven A1 - Huflage, Henner A1 - Weißenberger, Manuel A1 - Hartung, Viktor A1 - Patzer, Theresa Sophie A1 - Gruschwitz, Philipp A1 - Ergün, Süleyman A1 - Bley, Thorsten Alexander A1 - Feldle, Philipp T1 - Ultra-high-resolution photon-counting detector CT arthrography of the ankle: a feasibility study JF - Diagnostics N2 - This study was designed to investigate the image quality of ultra-high-resolution ankle arthrography employing a photon-counting detector CT. Bilateral arthrograms were acquired in four cadaveric specimens with full-dose (10 mGy) and low-dose (3 mGy) scan protocols. Three convolution kernels with different spatial frequencies were utilized for image reconstruction (ρ\(_{50}\); Br98: 39.0, Br84: 22.6, Br76: 16.5 lp/cm). Seven radiologists subjectively assessed the image quality regarding the depiction of bone, hyaline cartilage, and ligaments. An additional quantitative assessment comprised the measurement of noise and the computation of contrast-to-noise ratios (CNR). While an optimal depiction of bone tissue was achieved with the ultra-sharp Br98 kernel (S ≤ 0.043), the visualization of cartilage improved with lower modulation transfer functions at each dose level (p ≤ 0.014). The interrater reliability ranged from good to excellent for all assessed tissues (intraclass correlation coefficient ≥ 0.805). The noise levels in subcutaneous fat decreased with reduced spatial frequency (p < 0.001). Notably, the low-dose Br76 matched the CNR of the full-dose Br84 (p 0.999) and superseded Br98 (p < 0.001) in all tissues. Based on the reported results, a photon-counting detector CT arthrography of the ankle with an ultra-high-resolution collimation offers stellar image quality and tissue assessability, improving the evaluation of miniscule anatomical structures. While bone depiction was superior in combination with an ultra-sharp convolution kernel, soft tissue evaluation benefited from employing a lower spatial frequency. KW - photon-counting CT KW - arthrography KW - ankle KW - cartilage KW - radiation dosage Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-362622 SN - 2075-4418 VL - 13 IS - 13 ER - TY - JOUR A1 - Wirtz, Dieter C. A1 - Gravius, Sascha A1 - Ascherl, Rudolf A1 - Thorweihe, Miguel A1 - Forst, Raimund A1 - Noeth, Ulrich A1 - Maus, Uwe M. A1 - Wimmer, Matthias D. A1 - Zeiler, Guenther A1 - Deml, Moritz C. T1 - Uncemented femoral revision arthroplasty using a modular tapered, fluted titanium stem 5-to 16-year results of 163 cases JF - Acta Orthopaedica N2 - Background and purpose - Due to the relative lack of reports on the medium- to long-term clinical and radiographic results of modular femoral cementless revision, we conducted this study to evaluate the medium- to long-term results of uncemented femoral stem revisions using the modular MRP-TITAN stem with distal diaphyseal fixation in a consecutive patient series. Patients and methods - We retrospectively analyzed 163 femoral stem revisions performed between 1993 and 2001 with a mean follow-up of 10 (5-16) years. Clinical assessment included the Harris hip score (HHS) with reference to comorbidities and femoral defect sizes classified by Charnley and Paprosky. Intraoperative and postoperative complications were analyzed and the failure rate of the MRP stem for any reason was examined. Results - Mean HHS improved up to the last follow-up (37 (SD 24) vs. 79 (SD 19); p < 0.001). 99 cases (61%) had extensive bone defects (Paprosky IIB-III). Radiographic evaluation showed stable stem anchorage in 151 cases (93%) at the last follow-up. 10 implants (6%) failed for various reasons. Neither a breakage of a stem nor loosening of the morse taper junction was recorded. Kaplan-Meier survival analysis revealed a 10-year survival probability of 97% (95% CI: 95-100). Interpretation - This is one of the largest medium- to longterm analyses of cementless modular revision stems with distal diaphyseal anchorage. The modular MRP-TITAN was reliable, with a Kaplan-Meier survival probability of 97% at 10 years. KW - follow-up KW - distal fixation KW - bone loss KW - replacement KW - register KW - junction KW - cement KW - prosthesis KW - roentgenographic assessment KW - total HIP-arthroplasty Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-114555 SN - 1745-3674 VL - 85 IS - 6 ER - TY - BOOK A1 - Wang, Wen T1 - Validation of shRNA clones for gene silencing in 293FT cells N2 - ... N2 - The goal of the project was to establish knock down of mRNA in human mesenchymal stem cells. Since these cells are difficult to transfect, a viral approach is needed to achieve sufficient expression of e. g. shRNA in a high percentage of cells to allow for an efficient silencing of corresponding mRNAs. For this purpose for every gene product of interest, a number of shRNA clones have to be tested to detect an individual shRNA with sufficient efficacy. Lentiviral systems for shRNA approaches have recently become available. The principal advantage of the lentiviral system is that it allows gene silencing in nondividing cells and therefore expands the usefulness of the RNAi-based gene silencing system. Lentivirus-delivered shRNAs are capable of specific, highly stable and functional silencing of gene expression in a variety of cell types. Since the viral transfection of MSCs is a time consuming process that involves transfection of 293 FT cells plus transduction of target cells, for this thesis the following approach was chosen: genes of interest were checked for expression in 293FT cells by RT-PCR. These gene products can be silenced in 293FT cells simply by transfection of shRNA clones and efficacy was subsequently tested by RT-PCR. Beyond this thesis then the project can proceed with effective clones to transduce primary MSCs with individual shRNA clones identified as effective silencing tool in this thesis. KW - shRNA KW - RNAi KW - .................................................................... KW - shRNA KW - RNAi Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-25955 N1 - Aus rechtlichen Gründen wurde der Zugriff auf den Volltext zu diesem Dokument gesperrt. ER - TY - JOUR A1 - Borojević, Ana A1 - Jauković, Aleksandra A1 - Kukolj, Tamara A1 - Mojsilović, Slavko A1 - Obradović, Hristina A1 - Trivanović, Drenka A1 - Živanović, Milena A1 - Zečević, Željko A1 - Simić, Marija A1 - Gobeljić, Borko A1 - Vujić, Dragana A1 - Bugarski, Diana T1 - Vitamin D3 stimulates proliferation capacity, expression of pluripotency markers, and osteogenesis of human bone marrow mesenchymal stromal/stem cells, partly through SIRT1 signaling JF - Biomolecules N2 - The biology of vitamin D3 is well defined, as are the effects of its active metabolites on various cells, including mesenchymal stromal/stem cells (MSCs). However, the biological potential of its precursor, cholecalciferol (VD3), has not been sufficiently investigated, although its significance in regenerative medicine — mainly in combination with various biomaterial matrices — has been recognized. Given that VD3 preconditioning might also contribute to the improvement of cellular regenerative potential, the aim of this study was to investigate its effects on bone marrow (BM) MSC functions and the signaling pathways involved. For that purpose, the influence of VD3 on BM-MSCs obtained from young human donors was determined via MTT test, flow cytometric analysis, immunocytochemistry, and qRT-PCR. Our results revealed that VD3, following a 5-day treatment, stimulated proliferation, expression of pluripotency markers (NANOG, SOX2, and Oct4), and osteogenic differentiation potential in BM-MSCs, while it reduced their senescence. Moreover, increased sirtuin 1 (SIRT1) expression was detected upon treatment with VD3, which mediated VD3-promoted osteogenesis and, partially, the stemness features through NANOG and SOX2 upregulation. In contrast, the effects of VD3 on proliferation, Oct4 expression, and senescence were SIRT1-independent. Altogether, these data indicate that VD3 has strong potential to modulate BM-MSCs' features, partially through SIRT1 signaling, although the precise mechanisms merit further investigation. KW - bone marrow mesenchymal stromal cells (BM-MSCs) KW - vitamin D3 (cholecalciferol, VD3) KW - SIRT1 KW - regenerative potential KW - stemness KW - osteogenesis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262203 SN - 2218-273X VL - 12 IS - 2 ER - TY - JOUR A1 - Boelch, Sebastian P. A1 - Gurok, Anna A1 - Gilbert, Fabian A1 - Weißenberger, Manuel A1 - Rudert, Maximilian A1 - Barthel, Thomas A1 - Reppenhagen, Stephan T1 - Why compromise the patella? Five-year follow-up results of medial patellofemoral ligament reconstruction with soft tissue patellar fixation JF - International Orthopaedics N2 - Purpose This study investigates the redislocation rate and functional outcome at a minimum follow-up of five years after medial patellofemoral ligament (MPFL) reconstruction with soft tissue patellar fixation for patella instability. Methods Patients were retrospectively identified and knees were evaluated for trochlea dysplasia according to Dejour, for presence of patella alta and for presence of cartilage lesion at surgery. At a minimum follow-up of five years, information about an incident of redislocation was obtained. Kujala, Lysholm, and Tegner questionnaires as well as range of motion were used to measure functional outcome. Results Eighty-nine knees were included. Follow-up rate for redislocation was 79.8% and for functional outcome 58.4%. After a mean follow-up of 5.8 years, the redislocation rate was 5.6%. There was significant improvement of the Kujala score (68.8 to 88.2, p = 0.000) and of the Lysholm score (71.3 to 88.4, p = 0.000). Range of motion at follow-up was 149.0° (115–165). 77.5% of the knees had patella alta and 52.9% trochlear dysplasia types B, C, or D. Patellar cartilage legions were present in 54.2%. Redislocations occurred in knees with trochlear dysplasia type C in combination with patella alta. Conclusion MPFL reconstruction with soft tissue patellar fixation leads to significant improvement of knee function and low midterm redislocation rate. Patients with high-grade trochlear dysplasia should be considered for additional osseous correction. KW - MPFL KW - medial patellofemoral ligament KW - patella instability KW - patella dislocation KW - trochlear dysplasia KW - patella alta Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235751 SN - 0341-2695 VL - 45 ER -