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- Franzén, Lovisa, et al.
(författare)
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Spatially resolved transcriptomics of human and mouse fibrotic lung
- 2022
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 60
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by progressive and irreversible scarring of the lung tissue. Development of new efficacious and safe treatments is hampered by limited understanding of disease pathogenesis, lack of predictive preclinical models, and narrow therapeutic index of candidate drugs targeting complex biologies. Here, we tackle these aspects by generating spatially resolved transcriptomic maps of fibrotic lungs from clinical samples and a preclinical mouse model. We utilized the Visium platform to study parenchyma biopsies from four healthy lungs and regions of varying fibrotic severity from four IPF patient lungs. By mapping single cell RNA-seq data spatially, we were able to detect distinct fibroblast populations in different regions of the lesioned IPF lung, as well as the presence of various immune cell populations. To study lung fibrosis preclinically in vivo, the bleomycin mouse model is the most widely used alternative, although its translatability to human disease is disputed. Visium data from mouse lungs collected at two time points following bleomycin administration were generated, which allowed us to characterize the fibrotic lesions and inflammatory areas in their spatiotemporal context. In addition, mass spectrometry imaging was performed on adjacent tissue sections to provide paired spatial metabolomics. Herein, we have generated spatial maps of the lung fibrosis transcriptome from IPF lung biopsies and bleomycin-injured mouse lungs, providing an extensive resource to probe disease pathogenesis and animal model translatability.
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- Loyfer, N, et al.
(författare)
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A DNA methylation atlas of normal human cell types
- 2023
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 613:7943, s. 355-
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Tidskriftsartikel (refereegranskat)abstract
- DNA methylation is a fundamental epigenetic mark that governs gene expression and chromatin organization, thus providing a window into cellular identity and developmental processes1. Current datasets typically include only a fraction of methylation sites and are often based either on cell lines that underwent massive changes in culture or on tissues containing unspecified mixtures of cells2–5. Here we describe a human methylome atlas, based on deep whole-genome bisulfite sequencing, allowing fragment-level analysis across thousands of unique markers for 39 cell types sorted from 205 healthy tissue samples. Replicates of the same cell type are more than 99.5% identical, demonstrating the robustness of cell identity programmes to environmental perturbation. Unsupervised clustering of the atlas recapitulates key elements of tissue ontogeny and identifies methylation patterns retained since embryonic development. Loci uniquely unmethylated in an individual cell type often reside in transcriptional enhancers and contain DNA binding sites for tissue-specific transcriptional regulators. Uniquely hypermethylated loci are rare and are enriched for CpG islands, Polycomb targets and CTCF binding sites, suggesting a new role in shaping cell-type-specific chromatin looping. The atlas provides an essential resource for study of gene regulation and disease-associated genetic variants, and a wealth of potential tissue-specific biomarkers for use in liquid biopsies.
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- Warnes, William H., et al.
(författare)
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Improving participation of engineering students studying abroad: An international dual-degree program in materials science and mechanical engineering
- 2013
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 65:7, s. 840-845
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Tidskriftsartikel (refereegranskat)abstract
- By addressing two critical barriers that are known to prevent U.S. undergraduate engineering students from considering study abroad, namely, fitting the experience into highly structured engineering degree curricula and defraying the cost, recruitment of students can be quite satisfactory. Based on the unequal exchange of E.U. students participating in the program, it appears that the time to Bachelor's degree completion can be an important aspect for E.U. participation. With regard to the cost, the differential cost of participation compared to the students staying at their home university can be quite low (a few thousand dollars per year), making this type of program potentially affordable to sustain by providing small scholarships r stipends to the students. Finally, by partnering with foreign universities, OSU and UdS have been able to leverage their resources and provide the opportunity for students to pursue a Bachelor'sdegree in materials science or mechanical engineering, respectively.
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- Dong, Yiran, et al.
(författare)
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Physiology, Metabolism, and Fossilization of Hot-Spring Filamentous Microbial Mats
- 2019
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Ingår i: Astrobiology. - : MARY ANN LIEBERT, INC. - 1531-1074 .- 1557-8070. ; 19:12
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Tidskriftsartikel (refereegranskat)abstract
- The evolutionarily ancient Aquificales bacterium Sulfurihydrogenibium spp. dominates filamentous microbial mat communities in shallow, fast-flowing, and dysoxic hot-spring drainage systems around the world. In the present study, field observations of these fettuccini-like microbial mats at Mammoth Hot Springs in Yellowstone National Park are integrated with geology, geochemistry, hydrology, microscopy, and multi-omic molecular biology analyses. Strategic sampling of living filamentous mats along with the hot-spring CaCO3 (travertine) in which they are actively being entombed and fossilized has permitted the first direct linkage of Sulfurihydrogenibium spp. physiology and metabolism with the formation of distinct travertine streamer microbial biomarkers. Results indicate that, during chemoautotrophy and CO2 carbon fixation, the 87-98% Sulfurihydrogenibium-dominated mats utilize chaperons to facilitate enzyme stability and function. High-abundance transcripts and proteins for type IV pili and extracellular polymeric substances (EPSs) are consistent with their strong mucus-rich filaments tens of centimeters long that withstand hydrodynamic shear as they become encrusted by more than 5mm of travertine per day. Their primary energy source is the oxidation of reduced sulfur (e.g., sulfide, sulfur, or thiosulfate) and the simultaneous uptake of extremely low concentrations of dissolved O-2 facilitated by bd-type cytochromes. The formation of elevated travertine ridges permits the Sulfurihydrogenibium-dominated mats to create a shallow platform from which to access low levels of dissolved oxygen at the virtual exclusion of other microorganisms. These ridged travertine streamer microbial biomarkers are well preserved and create a robust fossil record of microbial physiological and metabolic activities in modern and ancient hot-spring ecosystems.
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- Feigelson, HS, et al.
(författare)
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Haplotype analysis of the HSD17B1 gene and risk of breast cancer: A comprehensive approach to multicenter analyses of prospective cohort studies
- 2006
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Ingår i: Cancer Research. - 1538-7445. ; 66:4, s. 2468-2475
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Tidskriftsartikel (refereegranskat)abstract
- The 17 beta-hydroxysteroid dehydrogenase 1 gene (HSD17B1) encodes 17HSD1, which catalyzes the final step of estradiol biosynthesis. Despite the important role of HSD17B1 in hormone metabolism, few epidemiologic studies of HSD17B1 and breast cancer have been conducted. This study includes 5,370 breast cancer cases and 7,480 matched controls from five large cohorts in the Breast and Prostate Cancer Cohort Consortium. We characterized variation in HSD17B1 by resequencing and dense genotyping a multiethnic sample and identified haplotype-tagging single nucleotide polymorphisms (htSNP) that capture common variation within a 33.3-kb region around HSD17B1. Four htSNPs, including the previously studied SNP rs605059 (S312G), were genotyped to tag five common haplotypes in all cases and controls. Conditional logistic regression was used to estimate odds ratios (OR) for disease. We found no evidence of association between common HSD17B1 haplotypes or htSNPs and overall risk of breast cancer. The OR for each haplotype relative to the most common haplotype ranged from 0.98 to 1.07 (omnibus test for association: X-2 = 3.77, P = 0.58, 5 degrees of freedom). When cases were subdivided by estrogen receptor (ER) status, two common haplotypes were associated with ER-negative tumors (test for trend, Ps = 0.0009 and 0.0076; n = 353 cases). HSD17B1 variants that are common in Caucasians are not associated with overall risk of breast cancer; however, there was an association among the subset of ER-negative tumors. Although the probability that these ER-negative findings are false-positive results is high, these findings were consistent across each cohort examined and warrant further study.
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- Isaksson, Hanna, et al.
(författare)
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Neutron tomographic imaging of bone-implant interface : Comparison with X-ray tomography
- 2017
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Ingår i: Bone. - : Elsevier BV. - 8756-3282. ; 103, s. 295-301
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Tidskriftsartikel (refereegranskat)abstract
- Metal implants, in e.g. joint replacements, are generally considered to be a success. As mechanical stability is important for the longevity of a prosthesis, the biological reaction of the bone to the mechanical loading conditions after implantation and during remodelling determines its fate. The bone reaction at the implant interface can be studied using high-resolution imaging. However, commonly used X-ray imaging suffers from image artefacts in the close proximity of metal implants, which limit the possibility to closely examine the bone at the bone-implant interface. An alternative ex vivo 3D imaging method is offered by neutron tomography. Neutrons interact with matter differently than X-rays; therefore, this study explores if neutron tomography may be used to enrich studies on bone-implant interfaces. A stainless steel screw was implanted in a rat tibia and left to integrate for 6 weeks. After extracting the tibia, the bone-screw construct was imaged using X-ray and neutron tomography at different resolutions. Artefacts were visible in all X-ray images in the close proximity of the implant, which limited the ability to accurately quantify the bone around the implant. In contrast, neutron images were free of metal artefacts, enabling full analysis of the bone-implant interface. Trabecular structural bone parameters were quantified in the metaphyseal bone away from the implant using all imaging modalities. The structural bone parameters were similar for all images except for the lowest resolution neutron images. This study presents the first proof-of-concept that neutron tomographic imaging can be used for ex-vivo evaluation of bone microstructure and that it constitutes a viable, new tool to study the bone-implant interface tissue remodelling.
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| 10. |
- Le Cann, Sophie, et al.
(författare)
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Investigating the mechanical characteristics of bone-metal implant interface using in situ synchrotron tomographic imaging
- 2019
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Ingår i: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media SA. - 2296-4185. ; 6:JAN
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Tidskriftsartikel (refereegranskat)abstract
- Long-term stability of endosseous implants depends on successful bone formation, ingrowth and adaptation to the implant. Specifically, it will define the mechanical properties of the newly formed bone-implant interface. 3D imaging during mechanical loading tests (in situ loading) can improve the understanding of the local processes leading to bone damage and failure. In this study, titanium screws were implanted into rat tibiae and were allowed to integrate for 4 weeks with or without the addition of the growth factor Bone Morphogenetic Protein and the bisphosphonate Zoledronic Acid. Samples were subjected to in situ pullout using high-resolution synchrotron x-ray tomography at the Tomcat beamline (SLS, PSI, Switzerland) at 30 keV with 25 ms exposure time, resulting in a total acquisition time of 45 s per scan, with a 3.6 μm isotropic voxel size. Using a custom-made loading device positioned inside the beamline, screws were pulled out with 0.05 mm increment, acquiring multiple scans until rupture of the sample. The in situ loading protocol was adapted to ensure short imaging time, which enabled multiple samples to be tested with short loading steps, while keeping the total testing time low and reducing dose deposition. Higher trabecular bone content was quantified in the surrounding of the screw in the treated groups, which correlated with increased mechanical strength and stiffness. Differences in screw implantation, such as contact between threads and cortex as well as minor tilt of the screw were also correlated to the mechanical parameters. In situ loading enabled the investigation of crack propagation during the pullout, highlighting the mechanical behavior of the interface. Three typical crack types were observed: (1) rupture at the interface of trabecular and cortical bone tissues, close to the screw, (2) large crack inside the cortex connected to the implant, and (3) first failure away from the screw with cracks propagating toward the screw-bone interface. Mechanical properties of in vivo integrated bone-metal screws rely on a combination of multiple parameters that are difficult to identify and separate one from the other.
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