| 281. |
- Abel, Frida, 1974, et al.
(författare)
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Analyses of apoptotic regulators CASP9 and DFFA at 1P36.2, reveal rare allele variants in human neuroblastoma tumours.
- 2002
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Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 86:4, s. 596-604
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Tidskriftsartikel (refereegranskat)abstract
- The genes encoding Caspase-9 and DFF45 have both recently been mapped to chromosome region 1p36.2, that is a region alleged to involve one or several tumour suppressor genes in neuroblastoma tumours. This study presents an update contig of the 'Smallest Region of Overlap of deletions' in Scandinavian neuroblastoma tumours and suggests that DFF45 is localized in the region. The genomic organization of the human DFF45 gene, deduced by in-silico comparisons of DNA sequences, is described for the first time in this paper. In the present study 44 primary tumours were screened for mutation by analysis of the genomic sequences of the genes. In two out of the 44 tumours this detected in the DFFA gene one rare allele variant that caused a non-polar to a polar amino acid exchange in a preserved hydrophobic patch of DFF45. One case was hemizygous due to deletion of the more common allele of this polymorphism. Out of 194 normal control alleles only one was found to carry this variant allele, so in respect of it, no healthy control individual out of 97 was homozygous. Moreover, our RT-PCR expression studies showed that DFF45 is preferably expressed in low-stage neuroblastoma tumours and to a lesser degree in high-stage neuroblastomas. We conclude that although coding mutations of Caspase-9 and DFF45 are infrequent in neuroblastoma tumours, our discovery of a rare allele in two neuroblastoma cases should be taken to warrant further studies of the role of DFF45 in neuroblastoma genetics.
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| 282. |
- Abel, Frida, 1974, et al.
(författare)
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Gain of chromosome arm 17q is associated with unfavourable prognosis in neuroblastoma, but does not involve mutations in the somatostatin receptor 2(SSTR2) gene at 17q24.
- 1999
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Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 81:8, s. 1402-9
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Tidskriftsartikel (refereegranskat)abstract
- Deletion of chromosome arm 1p and amplification of the MYCN oncogene are well-recognized genetic alterations in neuroblastoma cells. Recently, another alteration has been reported; gain of the distal part of chromosome arm 17q. In this study 48 neuroblastoma tumours were successfully analysed for 17q status in relation to known genetic alterations. Chromosome 17 status was detected by fluorescence in situ hybridization (FISH). Thirty-one of the 48 neuroblastomas (65%) showed 17q gain, and this was significantly associated with poor prognosis. As previously reported, 17q gain was significantly associated with metastatic stage 4 neuroblastoma and more frequently detected than both deletion of chromosome arm 1p and MYCN amplification in tumours of all stages. 17q gain also showed a strong correlation to survival probability (P = 0.0009). However, the most significant correlation between 17q gain and survival probability was observed in children with low-stage tumours (stage 1, 2, 3 and 4S), with a survival probability of 100% at 5 years from diagnosis for children with tumours showing no 17q gain compared to 52.5% for those showing 17q gain (P = 0.0021). This suggests that 17q gain as a prognostic factor plays a more crucial role in low-stage tumours. Expression of the somatostatin receptor 2 (SSTR2), localized in chromosome region 17q24, has in previous studies been shown to be positively related to survival in neuroblastoma. A point mutation in the SSTR2 gene has earlier been reported in a human small-cell lung cancer. In this study, mutation screening of the SSTR2 gene in 43 neuroblastoma tumours was carried out with polymerase chain reaction-based single-stranded conformation polymorphism/heteroduplex (SSCP/HD) and DNA sequencing, and none of the tumours showed any aberrations in the SSTR2 gene. These data suggest that mutations in the SSTR2 gene are uncommon in neuroblastoma tumours and do not correlate with either the 17q gain often seen or the reason some tumours do not express SSTR2 receptors. Overall, this study indicates that gain of chromosome arm 17q is the most frequently occurring genetic alteration, and that it is associated with established prognostic factors.
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| 283. |
- Abel, Frida, 1974
(författare)
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Genetic studies of neuroblastoma with emphasis on the apoptotic pathway
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aim: The objective of this thesis was to find genes and chromosomal regions involved in neuroblastoma (NB) tumor progression. NB is a childhood tumor of the sympathetic nervous system that generally occurs spontaneously. Biologically, NB has a complex heterogeneity from tumor progression to tumor regression, dependent on clinical stage and age at diagnosis. The main genetic markers, which are also of prognostic value in NB, are amplification of the oncogene MYCN, deletion of chromosome arm 1p and gain of chromosome arm 17q. Results: We have been shown using fluorescence in situ hybridization (FISH) on a Scandinavian tumor material, that 17q gain is present in approximately 65% of all NB stages, is significantly associated with poor prognosis and predicts survival. The gene encoding somatostatin receptor 2 (SSTR2), localized in chromosome region 17q24, was not found to be mutated in any NB, when analyzed with PCR-based single stranded conformation polymorphism/heteroduplex (SSCP/HD) and DNA sequencing. In a tentative effort of defining of the location of a general embryonal tumor suppressor gene (TSG) on 1p, we combined the smallest region of overlap (SRO) of 1p deletions in NB tumors and germ cell tumors (GCTs). We thus delimited the NB/GCT SRO to approximately 5 cM between markers D1S508 and D1S244, and fine-mapped this region by radiation hybrid mapping and construction of a bacterial artificial chromosome (BAC) contig. A homozygously deleted region in an NB cell line was found to partially overlap the proximal part of the 5 cM-SRO defined by us, which further focused our search for a TSG to a 500 kb candidate region in 1p36.22. Two attractive candidate NB TSGs, DFFA and CASP9, are both located in 1p36.2 and encode key apoptotic mediators. In fact, DFFA resides in the 500 kb TSG candidate region. Via sequence analysis of the entire tumor material, we found three different coding alterations in DFFA which all affect the highly conserved N-terminal regulatory domain of DFF45. Using RT-PCR and real-time RT-PCR (TaqMan) studies, we were able to show that both DFFA and CASP9 are preferably expressed in NB tumors with favorable outcome. It has been proposed that lack of apoptosis plays an important role in tumor progression. We therefore screened an array with cDNAs involved in the apoptotic process, to find genes differentially expressed in NB tumors with unfavorable versus favorable biology. Using real-time RT-PCR analysis, we verified the differential expression of several transcripts encoding mitochondrial apoptotic mediators. Conclusions: We have shown that 17q gain is the most frequently detected alteration in NB and that it is associated with established prognostic factors. We narrowed down the TSG candidate region on 1p and found mutations in a gene localized in the region possessing fundamental functions in apoptosis. Our results also suggest that the mitochondrial apoptotic pathway is suppressed at multiple steps in advanced stages of NB tumors, due to imbalance between anti-apoptotic and pro-apoptotic mediators.
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| 284. |
- Abel, Frida, 1974, et al.
(författare)
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Imbalance of the mitochondrial pro- and anti-apoptotic mediators in neuroblastoma tumours with unfavourable biology.
- 2005
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Ingår i: European journal of cancer (Oxford, England : 1990). - : Elsevier BV. - 0959-8049. ; 41:4, s. 635-46
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Tidskriftsartikel (refereegranskat)abstract
- It has been proposed that a lack of apoptosis plays an important role in neuroblastoma (NB) progression. We therefore screened cDNA array filters, including 198 apoptotic genes, in order to identify mRNA transcripts that are differentially expressed in tumours with unfavourable versus favourable biology. Twenty-one genes were analysed further using real-time reverse-transcriptase-polymerase chain reaction (RT-PCR). Significantly lower levels of DNCL1 (PIN; P(c)(corrected) = 0.0054) and NTRK1 (TrkA; P(c) = 0.039) were found in NB tumours with unfavourable biology. In addition, BID, BCL2, APAF1, CASP2, CASP3 and CASP9 were found to be preferentially expressed in tumours with favourable biology, whereas CDKN1A (p21), IL2RA, and MCL1, were found to be preferentially expressed in NB tumours with unfavourable biology. In conclusion, mRNA levels of transcripts encoding pro-apoptotic mediators of the mitochondrial apoptotic pathway were found to be expressed to a lower extent in tumours with unfavourable biology. Our data also suggest that the mitochondrial pathway is suppressed in advanced stages of NB tumours, due to an imbalance between anti-apoptotic and pro-apoptotic mediators which is a finding that may have therapeutic significance.
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| 285. |
- Abel, Frida, 1974, et al.
(författare)
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Mutations in the N-terminal domain of DFF45 in a primary germ cell tumor and in neuroblastoma tumors.
- 2004
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Ingår i: International journal of oncology. - 1019-6439 .- 1791-2423. ; 25:5, s. 1297-302
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Tidskriftsartikel (refereegranskat)abstract
- DFF45 has essential functions in the final stage of apoptosis by acting both as a folding chaperone and a DNase inhibitor of DFF40. The gene encoding DFF45 (DFFA) maps to the consensus deleted region in primary neuroblastoma (NB; 1p36.2-3) and within the homozygously deleted region in an NB cell line (1p36.2). DFF45 is therefore an attractive candidate NB tumor suppressor. In a previous study we found a rare allele variant, causing a non-polar to a polar amino acid exchange (Ile69Thr) in a preserved hydrophobic patch of DFF45, and we also found DFFA to be preferentially expressed in favorable NB tumors. We have extended the previous study and performed mutation analyses in another 56 NB tumors (100 in total) as well as a set of other tumors for coding mutations in DFFA. We have also performed studies of the DFFA expression in tumors using real-time PCR. We found a missense mutation (Ile15Met) in the remaining allele of a teratoma with heterozygous deletion of 1p, and a three base-pair deletion in an NB of unknown stage causing a deletion of amino acid 37 in DFF45. The one-base substitution detected in the teratoma was not present in the patients constitutional DNA, i.e. it is a true mutation present in the tumor DNA only. In conclusion, three different coding alterations have been found in the region encoding the N-terminal regulatory domain of DFF45, responsible for binding and achieving its chaperone and inhibitor functions on other proteins. Moreover, by real-time RT-PCR expression study, we found the mRNA level of DFFA to be significantly (p=0.038) reduced by a factor of 1.7 times in NB tumors of unfavorable outcome.
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| 286. |
- Abel, Martin, et al.
(författare)
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Collision-induced absorption at wavelengths near 5 micrometers by dense hydrogen gas
- 2009
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Ingår i: J. Chem. Phys.. - : AIP Publishing. ; 131
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Tidskriftsartikel (refereegranskat)abstract
- Based on a recent ab initio interaction-induced dipole surface of collisionally interacting molecular hydrogen pairs H2–H2, we compute the binary absorption coefficients at wavelengths near 5 micrometers at temperatures of 77.5 and 297 K for comparison with existing laboratory measurements. We observe satisfactory agreement of the measurements with our calculations, thereby concluding an earlier study [Gustafsson et al., J. Chem. Phys. 119, 12264 (2003)], which was based on an ab initio interaction-induced dipole surface that was inadequate for the 5 micrometer band.
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| 287. |
- Abel, Martin, et al.
(författare)
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Collision-induced absorption by supermolecular complexes from a new potential energy and induced dipole surface, suited for calculations up to thousands of kelvin
- 2010
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Ingår i: 20th International Conference on Spectral Line Shapes. - Melville, NY : American Institute of Physics (AIP). - 9780735408456 ; , s. 251-257
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Konferensbidrag (refereegranskat)abstract
- Absorption by pairs of H2 molecules is an important opacity source in the atmospheres of the outer planets, and thus of special astronomical interest. The emission spectra of cool white dwarf stars differ significantly from the expected blackbody spectra, amongst other reasons due to absorption by H2-H2, H2-He, and H2-H collisional complexes in the stellar atmospheres. To model the radiative processes in these atmospheres, which have temperatures of several thousand kelvin, one needs accurate knowledge of the induced dipole (ID) and potential energy surfaces (PES) of such collisional complexes. These come from quantum-chemical calculations with the H2 bonds stretched or compressed far from equilibrium. Laboratory measurements of collision-induced (CI) absorption exist only at much lower temperature. For H2 pairs at room temperature, the calculated spectra of the rototranslational band, the fundamental band, and the first overtone match the experimental data very well. In addition, with the newly obtained IDS it became possible to reproduce the measurements in the far blue wing of the rototranslational spectrum of H2 at 77.5 K, as well as at 300 K. Similarly good agreement between theory and measurement is seen in the fundamental band of molecular deuterium at room temperature. Furthermore, we also show the calculated absorption spectra of H2-He at 600 K and of H2-H2 at 2,000 K, for which there are no experimental data for comparison
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| 288. |
- Abel, Marianne Hope, et al.
(författare)
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Insufficient maternal iodine intake is associated with subfecundity, reduced foetal growth, and adverse pregnancy outcomes in the Norwegian Mother, Father and Child Cohort Study.
- 2020
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Ingår i: BMC medicine. - : Springer Science and Business Media LLC. - 1741-7015. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Severe iodine deficiency impacts fertility and reproductive outcomes. The potential effects of mild-to-moderate iodine deficiency are not well known. The aim of this study was to examine whether iodine intake was associated with subfecundity (i.e. > 12 months trying to get pregnant), foetal growth, and adverse pregnancy outcomes in a mild-to-moderately iodine-deficient population.We used the Norwegian Mother, Father and Child Cohort Study (MoBa) and included 78,318 pregnancies with data on iodine intake and pregnancy outcomes. Iodine intake was calculated using an extensive food frequency questionnaire in mid-pregnancy. In addition, urinary iodine concentration was available in a subsample of 2795 pregnancies. Associations were modelled continuously by multivariable regression controlling for a range of confounding factors.The median iodine intake from food was 121 μg/day and the median urinary iodine was 69 μg/L, confirming mild-to-moderate iodine deficiency. In non-users of iodine supplements (n = 49,187), low iodine intake (< 100-150 μg/day) was associated with increased risk of preeclampsia (aOR = 1.14 (95% CI 1.08, 1.22) at 75 vs. 100 μg/day, p overall < 0.001), preterm delivery before gestational week 37 (aOR = 1.10 (1.04, 1.16) at 75 vs. 100 μg/day, p overall = 0.003), and reduced foetal growth (- 0.08 SD (- 0.10, - 0.06) difference in birth weight z-score at 75 vs. 150 μg/day, p overall < 0.001), but not with early preterm delivery or intrauterine death. In planned pregnancies (n = 56,416), having an iodine intake lower than ~ 100 μg/day was associated with increased prevalence of subfecundity (aOR = 1.05 (1.01, 1.09) at 75 μg/day vs. 100 μg/day, p overall = 0.005). Long-term iodine supplement use (initiated before pregnancy) was associated with increased foetal growth (+ 0.05 SD (0.03, 0.07) on birth weight z-score, p < 0.001) and reduced risk of preeclampsia (aOR 0.85 (0.74, 0.98), p = 0.022), but not with the other adverse pregnancy outcomes. Urinary iodine concentration was not associated with any of the dichotomous outcomes, but positively associated with foetal growth (n = 2795, p overall = 0.017).This study shows that a low iodine intake was associated with restricted foetal growth and a higher prevalence of preeclampsia in these mild-to-moderately iodine-deficient women. Results also indicated increased risk of subfecundity and preterm delivery. Initiating iodine supplement use in pregnancy may be too late.
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| 289. |
- Abeler-Dörner, Lucie, et al.
(författare)
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Butyrophilins: an emerging family of immune regulators
- 2012
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Ingår i: Trends in immunology. - : Elsevier BV. - 1471-4906 .- 1471-4981. ; 33:1, s. 34-41
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Forskningsöversikt (refereegranskat)abstract
- Butyrophilins (Btns) and butyrophilin-like (Btnl) molecules are emerging as novel regulators of immune responses in mice and humans. Several clues point to their probable importance: many of the genes are located within the MHC; they are structurally related to B7-co-stimulatory molecules; they are functionally implicated in T cell inhibition and in the modulation of epithelial cell-T cell interactions; and they are genetically associated with inflammatory diseases. Nonetheless, initial immersion into the current literature can uncover confusion over even basic information such as gene names and expression patterns, and seemingly conflicting data regarding the biological activities of different family members. This review addresses each of these issues, concluding with the attractive potential of Btn and Btnl molecules to act as specific attenuators of tissue-associated inflammatory responses.
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| 290. |
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