| 1. |
|
|
| 2. |
- Feldhahn, Niklas, et al.
(author)
-
Activation-induced cytidine deaminase acts as a mutator in BCR-ABL1-transformed acute lymphoblastic leukemia cells
- 2007
-
In: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 204:5, s. 1157-1166
-
Journal article (peer-reviewed)abstract
- The Philadelphia chromosome (Ph) encoding the oncogenic BCR-ABL1 kinase defines a subset of acute lymphoblastic leukemia (ALL) with a particularly unfavorable prognosis. ALL cells are derived from B cell precursors in most cases and typically carry rearranged immunoglobulin heavy chain (IGH) variable (V) region genes devoid of somatic mutations. Somatic hypermutation is restricted to mature germinal center B cells and depends on activation-induced cytidine deaminase (AID). Studying AID expression in 108 cases of ALL, we detected AID mRNA in 24 of 28 Ph(+) ALLs as compared with 6 of 80 Ph(-) ALLs. Forced expression of BCR-ABL1 in Ph(-) ALL cells and inhibition of the BCR-ABL1 kinase showed that aberrant expression of AID depends on BCR-ABL1 kinase activity. Consistent with aberrant AID expression in Ph(+) ALL, IGH V region genes and BCL6 were mutated in many Ph(+) but unmutated in most Ph(-) cases. In addition, AID introduced DNA single-strand breaks within the tumor suppressor gene CDKN2B in Ph(+) ALL cells, which was sensitive to BCR-ABL1 kinase inhibition and silencing of AID expression by RNA interference. These findings identify AID as a BCR-ABL1-induced mutator in Ph(+) ALL cells, which may be relevant with respect to the particularly unfavorable prognosis of this leukemia subset.
|
|
| 3. |
- Grun, E., et al.
(author)
-
The 2016 Feb 19 outburst of comet 67P/CG : an ESA Rosetta multi-instrument study
- 2016
-
In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 462, s. S220-S234
-
Journal article (peer-reviewed)abstract
- On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09: 40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors > 100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors > 10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from similar to-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta ( 34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (similar to 25 m s(-1)) while 100 mu m radius particles were detected by the GIADA dust instrument similar to 1 h later at a speed of 6 m s(-1). The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.
|
|
| 4. |
- Helgesson, Gert, et al.
(author)
-
Misuse of co-authorship in Medical PhD Theses in Scandinavia : A Questionnaire Survey
- 2023
-
In: Journal of Academic Ethics. - : Springer Nature. - 1570-1727 .- 1572-8544. ; 21:3, s. 393-406
-
Journal article (peer-reviewed)abstract
- BackgroundSeveral studies suggest that deviations from proper authorship practices are commonplace in medicine. The aim of this study was to explore experiences of and attitudes towards the handling of authorship in PhD theses at medical faculties in Denmark, Norway, and Sweden.MethodsThose who defended their PhD thesis at a medical faculty in Scandinavia during the second half of 2020 were offered, by e-mail, to participate in an online survey. Survey questions dealt with experiences of violations of the first three of the ICMJE authorship criteria and misuse of authorship order in the thesis articles, as well as respondents’ attitudes to these matters. Both questions with fixed response alternatives and questions with free-text responses were used. Quantitative data were analysed statistically using the Table functions in SPSS 25 and Chi-2 tests. Free-text responses were analysed qualitatively using manifest content analysis.Results287 valid questionnaires were returned (response rate: 34.1%). Almost half (46.0%) of the respondents reported that the ICMJE authorship criteria were not fully respected in at least one of the papers in their thesis, while a vast majority (96.7%) found it important that authorship is handled according to the ICMJE authorship criteria. 24.4% reported inadequate handling of authorship order in at least one paper. The qualitative results provide a wide spectrum of examples of how the ICMJE authorship criteria are circumvented.ConclusionDespite increasing educational efforts to reduce deviations from good research practice at Scandinavian universities, the handling of authorship in medical papers remains problematic.
|
|
| 5. |
- Hofmann, Niklas, et al.
(author)
-
Link between interlayer hybridization and ultrafast charge transfer in WS 2 -graphene heterostructures
- 2023
-
In: 2D Materials. - 2053-1583. ; 10:3
-
Journal article (peer-reviewed)abstract
- Ultrafast charge separation after photoexcitation is a common phenomenon in various van-der-Waals (vdW) heterostructures with great relevance for future applications in light harvesting and detection. Theoretical understanding of this phenomenon converges towards a coherent mechanism through charge transfer states accompanied by energy dissipation into strongly coupled phonons. The detailed microscopic pathways are material specific as they sensitively depend on the band structures of the individual layers, the relative band alignment in the heterostructure, the twist angle between the layers, and interlayer interactions resulting in hybridization. We used time- and angle-resolved photoemission spectroscopy combined with tight binding and density functional theory electronic structure calculations to investigate ultrafast charge separation and recombination in WS2-graphene vdW heterostructures. We identify several avoided crossings in the band structure and discuss their relevance for ultrafast charge transfer. We relate our own observations to existing theoretical models and propose a unified picture for ultrafast charge transfer in vdW heterostructures where band alignment and twist angle emerge as the most important control parameters.
|
|
| 6. |
|
|
| 7. |
- Tremmel, Roman, et al.
(author)
-
Hepatic Expression of the Na+-Taurocholate Cotransporting Polypeptide Is Independent from Genetic Variation
- 2022
-
In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 23:13
-
Journal article (peer-reviewed)abstract
- The hepatic Na+-taurocholate cotransporting polypeptide NTCP/SLC10A1 is important for the uptake of bile salts and selected drugs. Its inhibition results in increased systemic bile salt concentrations. NTCP is also the entry receptor for the hepatitis B/D virus. We investigated interindividual hepatic SLC10A1/NTCP expression using various omics technologies. SLC10A1/NTCP mRNA expression/protein abundance was quantified in well-characterized 143 human livers by real-time PCR and LC-MS/MS-based targeted proteomics. Genome-wide SNP arrays and SLC10A1 next-generation sequencing were used for genomic analyses. SLC10A1 DNA methylation was assessed through MALDI-TOF MS. Transcriptomics and untargeted metabolomics (UHPLC-Q-TOF-MS) were correlated to identify NTCP-related metabolic pathways. SLC10A1 mRNA and NTCP protein levels varied 44-fold and 10.4-fold, respectively. Non-genetic factors (e.g., smoking, alcohol consumption) influenced significantly NTCP expression. Genetic variants in SLC10A1 or other genes do not explain expression variability which was validated in livers (n = 50) from The Cancer Genome Atlas. The identified two missense SLC10A1 variants did not impair transport function in transfectants. Specific CpG sites in SLC10A1 as well as single metabolic alterations and pathways (e.g., peroxisomal and bile acid synthesis) were significantly associated with expression. Inter-individual variability of NTCP expression is multifactorial with the contribution of clinical factors, DNA methylation, transcriptional regulation as well as hepatic metabolism, but not genetic variation.
|
|
| 8. |
- Tremmel, Roman, et al.
(author)
-
Non-genetic and epigenetic factors contribute to inter-individualvariability of the hepatic bile acid and drug transporter NTCP : Hepatic variability of the hepatic bile acid and drug transporter NTCP
-
Other publication (other academic/artistic)abstract
- Background and Purpose: The hepatic Na+-taurocholate cotransporting polypeptide NTCP/SLC10A1 plays an importantrole in the uptake of bile salts and drugs, and as key receptor for hepatitis B/D virus entry. NTCPinhibitors are investigated for treatment of HBV/HDV-infection. We performed a comprehensivemulti-omics approach to investigate underlying mechanisms of inter-individual variability ofNTCP expression in Caucasians.Experimental Approach: mRNA/protein expression of SLC10A1/NTCP was quantified in 143 well-characterized nontumorhuman liver samples by real-time PCR and LC-MS/MS-based targeted proteomics,respectively. Genetic variants were investigated using genome-wide SNP arrays and nextgenerationsequencing. DNA methylation of the SLC10A1 promoter region was investigatedthrough MALDI-TOF MS. Untargeted metabolomics of liver tissues was performed by UHPLC-QTOFMS.Key Results: The SLC10A1 mRNA expression showed a 44-fold variation in liver samples, whereas NTCPprotein expression varied 10.4-fold. Genome-wide association analyses and in-depth SLC10A1sequencing indicates that genetic variants either in SLC10A1 or other genes, cannot explainexpression variability. Only two missense SLC10A1 variants were identified. NTCP proteinexpression is significantly influenced by non-genetic factors (e.g. smoking, alcoholconsumption). DNA methylation analysis revealed a significant association of specific CpG-siteswith protein expression (p<0.05). Additionally, variable expression is associated with metabolicalterations determined through gene set enrichment and untargeted metabolomics. Findingswere validated partly in livers (n=50) from The Cancer Genome Atlas.Conclusion and Implications: Inter-individual variability of NTCP expression is multifactorial with a significant contribution ofDNA methylation. Functional genetic variants are negligible and may not limit targeting of NTCPby novel inhibitors for treatment of HBV/HDV-infection.
|
|
