TY - JOUR A1 - Langhauser, Friederike L. A1 - Heiler, Patrick M. A1 - Grudzenski, Saskia A1 - Lemke, Andreas A1 - Alonso, Angelika A1 - Schad, Lothar R. A1 - Hennerici, Michael G. A1 - Meairs, Stephen A1 - Fata, Marc T1 - Thromboembolic stroke in C57BL/6 mice monitored by 9.4 T MRI using a 1H cryo probe JF - Experimental and Translational Stroke Medicine N2 - Background A new thromboembolic animal model showed beneficial effects of t-PA with an infarct volume reduction of 36.8% in swiss mice. Because knock-out animal experiments for stroke frequently used C57BL76 mice we evaluated t-PA effects in this mouse strain and measured infarct volume and vascular recanalisation in-vivo by using high-field 9.4 T MRI and a 1H surface cryo coil. Methods Clot formation was triggered by microinjection of murine thrombin into the right middle cerebral artery (MCA). Animals (n = 28) were treated with 10 mg/kg, 5 mg/kg or no tissue plasminogen activator (t-PA) 40 min after MCA occlusion. For MR-imaging a Bruker 9.4 T animal system with a 1H surface cryo probe was used and a T2-weighted RARE sequence, a diffusion weighted multishot EPI sequence and a 3D flow-compensated gradient echo TOF angiography were performed. Results The infarct volume in animals treated with t-PA was significantly reduced (0.67 ± 1.38 mm3 for 10 mg/kg and 10.9 ± 8.79 mm3 for 5 mg/kg vs. 19.76 ± 2.72 mm3 ; p < 0.001) compared to untreated mice. An additional group was reperfused with t-PA inside the MRI. Already ten minutes after beginning of t-PA treatment, reperfusion flow was re-established in the right MCA. However, signal intensity was lower than in the contralateral MCA. This reduction in cerebral blood flow was attenuated during the first 60 minutes after reperfusion. 24 h after MCA occlusion and reperfusion, no difference in signal intensity of the contralateral and ipsilateral MCAs was observed. Conclusions We confirm a t-Pa effect using this stroke model in the C57BL76 mouse strain and demonstrate a chronological sequence MRI imaging after t-PA using a 1H surface cryo coil in a 9.4 T MRI. This setting will allow testing of new thrombolytic strategies for stroke treatment in-vivo in C57BL76 knock-out mice. KW - animal models KW - MRI KW - experimental KW - embolic stroke KW - T-PA Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124218 VL - 4 IS - 18 ER - TY - JOUR A1 - Sepahi, Ilnaz A1 - Faust, Ulrike A1 - Sturm, Marc A1 - Bosse, Kristin A1 - Kehrer, Martin A1 - Heinrich, Tilman A1 - Grundman-Hauser, Kathrin A1 - Bauer, Peter A1 - Ossowski, Stephan A1 - Susak, Hana A1 - Varon, Raymonda A1 - Schröck, Evelin A1 - Niederacher, Dieter A1 - Auber, Bernd A1 - Sutter, Christian A1 - Arnold, Norbert A1 - Hahnen, Eric A1 - Dworniczak, Bernd A1 - Wang-Gorke, Shan A1 - Gehrig, Andrea A1 - Weber, Bernhard H. F. A1 - Engel, Christoph A1 - Lemke, Johannes R. A1 - Hartkopf, Andreas A1 - Huu Phuc, Nguyen A1 - Riess, Olaf A1 - Schroeder, Christopher T1 - Investigating the effects of additional truncating variants in DNA-repair genes on breast cancer risk in BRCA1-positive women JF - BMC Cancer N2 - Background Inherited pathogenic variants in BRCA1 and BRCA2 are the most common causes of hereditary breast and ovarian cancer (HBOC). The risk of developing breast cancer by age 80 in women carrying a BRCA1 pathogenic variant is 72%. The lifetime risk varies between families and even within affected individuals of the same family. The cause of this variability is largely unknown, but it is hypothesized that additional genetic factors contribute to differences in age at onset (AAO). Here we investigated whether truncating and rare missense variants in genes of different DNA-repair pathways contribute to this phenomenon. Methods We used extreme phenotype sampling to recruit 133 BRCA1-positive patients with either early breast cancer onset, below 35 (early AAO cohort) or cancer-free by age 60 (controls). Next Generation Sequencing (NGS) was used to screen for variants in 311 genes involved in different DNA-repair pathways. Results Patients with an early AAO (73 women) had developed breast cancer at a median age of 27 years (interquartile range (IQR); 25.00–27.00 years). A total of 3703 variants were detected in all patients and 43 of those (1.2%) were truncating variants. The truncating variants were found in 26 women of the early AAO group (35.6%; 95%-CI 24.7 - 47.7%) compared to 16 women of controls (26.7%; 95%-CI 16.1 to 39.7%). When adjusted for environmental factors and family history, the odds ratio indicated an increased breast cancer risk for those carrying an additional truncating DNA-repair variant to BRCA1 mutation (OR: 3.1; 95%-CI 0.92 to 11.5; p-value = 0.07), although it did not reach the conventionally acceptable significance level of 0.05. Conclusions To our knowledge this is the first time that the combined effect of truncating variants in DNA-repair genes on AAO in patients with hereditary breast cancer is investigated. Our results indicate that co-occurring truncating variants might be associated with an earlier onset of breast cancer in BRCA1-positive patients. Larger cohorts are needed to confirm these results. KW - breast cancer KW - age at onset KW - DNA-repair genes KW - next-generation-sequencing KW - panel sequencing KW - extreme phenotypes KW - hereditary breast and ovarian cancer KW - BRCA1 KW - DNA-repair Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-237676 VL - 19 ER -