| 1. |
- Akhtar, Monira, et al.
(författare)
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Cell type and context-specific function of PLAG1 for IGF2 P3 promoter activity
- 2012
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Ingår i: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 41:6, s. 1959-1966
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Tidskriftsartikel (refereegranskat)abstract
- The fetal transcription factor PLAG1 is found to be overexpressed in cancers, and has been suggested to bind the insulin like growth factor 2 (IGF2) P3 promoter, and to activate the IGF2 gene. The expression of IGF2 has partly been linked to loss of CTCF-dependent chromatin insulator function at the H19 imprinting control region (ICR). We investigated the role of PLAG1 for IGF2 regulation in Hep3B and JEG-3 cell lines. Chromatin immunoprecipitation revealed cell type-specific binding of PLAG1 to the IGF2 P3 promoter, which was substantially insensitive to recombinant PLAG1 overexpression in the endogenous context. We hypothesized that the H19 chromatin insulator may be involved in the cell type-specific PLAG1 response. By using a GFP reporter gene/insulator assay plasmid construct with and without the H19 ICR and/or an SV40 enhancer, we confirm that the effect of the insulator is specifically associated with the activity of the IGF2 P3 promoter in the GFP reporter system, and furthermore, that the reporter insulator is functional in JEG-3 but not in Hep3B cells. FACS analysis was used to assess the function of PLAG1 in low endogenously expressing, but Zn-inducible stable PLAG1 expressing JEG-3 cell clones. Considerable increase in IGF2 expression upon PLAG1 induction with a partial insulator overriding activity was found using the reporter constructs. This is in contrast to the effect of the endogenous IGF2 gene which was insensitive to PLAG1 expression in JEG-3, while modestly induced the already highly expressed IGF2 gene in Hep3B cells. We suggest that the PLAG1 binding to the IGF2 P3 promoter and IGF2 expression is cell type-specific, and that the PLAG1 transcription factor acts as a transcriptional facilitator that partially overrides the insulation by the H19 ICR.
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| 2. |
- Bhatt, Deepak L., et al.
(författare)
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Rationale, design and baseline characteristics of the effect of ticagrelor on health outcomes in diabetes mellitus patients Intervention study
- 2019
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Ingår i: Clinical Cardiology. - : Wiley. - 0160-9289 .- 1932-8737. ; 42:5, s. 498-505
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Tidskriftsartikel (refereegranskat)abstract
- In the setting of prior myocardial infarction, the oral antiplatelet ticagrelor added to aspirin reduced the risk of recurrent ischemic events, especially, in those with diabetes mellitus. Patients with stable coronary disease and diabetes are also at elevated risk and might benefit from dual antiplatelet therapy. The Effect of Ticagrelor on Health Outcomes in diabEtes Mellitus patients Intervention Study (THEMIS, NCT01991795) is a Phase 3b randomized, double-blinded, placebo-controlled trial of ticagrelor vs placebo, on top of low dose aspirin. Patients >= 50 years with type 2 diabetes receiving anti-diabetic medications for at least 6 months with stable coronary artery disease as determined by a history of previous percutaneous coronary intervention, bypass grafting, or angiographic stenosis of >= 50% of at least one coronary artery were enrolled. Patients with known prior myocardial infarction (MI) or stroke were excluded. The primary efficacy endpoint is a composite of cardiovascular death, myocardial infarction, or stroke. The primary safety endpoint is Thrombolysis in Myocardial Infarction major bleeding. A total of 19 220 patients worldwide have been randomized and at least 1385 adjudicated primary efficacy endpoint events are expected to be available for analysis, with an expected average follow-up of 40 months (maximum 58 months). Most of the exposure is on a 60 mg twice daily dose, as the dose was lowered from 90 mg twice daily partway into the study. The results may revise the boundaries of efficacy for dual antiplatelet therapy and whether it has a role outside acute coronary syndromes, prior myocardial infarction, or percutaneous coronary intervention.
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| 3. |
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| 4. |
- Claes, Julien, et al.
(författare)
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Nitric oxide in the control of luminescence from lantern shark (Etmopterus spinax)
- 2010
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Ingår i: JOURNAL OF EXPERIMENTAL BIOLOGY. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 213:17, s. 3005-3011
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Photophores (photogenic organs) of the lantern shark Etmopterus spinax are under hormonal control, with prolactin (PRL) and melatonin (MT) triggering the light emission. Differential sensitivity to these hormones in adult individuals suggests, however, that the luminescence of this shark is controlled by an additional mechanism. In this study, different techniques were used to investigate a potential modulator of E. spinax luminescence-nitric oxide (NO). NO synthase (NOS)-like immunoreactivity (IR) was found in the photocytes (photogenic cells) of the photophores. In addition, acetylated tubulin IR also supported the presence of nerves running through the photogenic tissue and innervating different structural elements of the photophores: photocytes, pigmented cells from the iris-like structure and lens cells. Pharmacological experiments confirmed a modulatory action of NO on the hormonally induced luminescence: NO donors sodium nitroprusside (SNP) and hydroxylamine decreased the time to reach the maximum amplitude (TLmax) of MT-induced luminescence while these substances decreased the maximum amplitude of PRL-induced luminescence (and also the TLmax in the case of SNP). The small impact of the NOS inhibitor L-NAME on hormonally induced luminescence suggests that NO is only produced on demand. The cGMP analogue 8BrcGMP mimicked the effects of NO donors suggesting that the effects of NO are mediated by cGMP.
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| 5. |
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| 6. |
- FitzGerald, Edward A., et al.
(författare)
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Multiplexed experimental strategies for fragment library screening using SPR biosensors
- 2020
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Surface plasmon resonance biosensor technology (SPR) is ideally suited for fragment-based lead discovery. However, generally suitable experimental procedures or detailed protocols are lacking, especially for structurally or physico-chemically challenging targets or when tool compounds are lacking. Success depends on accounting for the features of both the target and the chemical library, purposely designing screening experiments for identification and validation of hits with desired specificity and mode-of-action, and availability of orthogonal methods capable of confirming fragment hits. By adopting a multiplexed strategy, the range of targets and libraries amenable to an SPR biosensor-based approach for identifying hits is considerably expanded. We here illustrate innovative strategies using five challenging targets and variants thereof. Two libraries of 90 and 1056 fragments were screened using two different flow-based SPR biosensor systems, allowing different experimental approaches. Practical considerations and procedures accounting for the characteristics of the proteins and libraries, and that increase robustness, sensitivity, throughput and versatility are highlighted.Competing Interest StatementAnna Moberg, Maria T. Lindgren and Claes Holmgren work for Cytiva, which produce Biacore systems.
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| 7. |
- FitzGerald, Edward, et al.
(författare)
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Multiplexed experimental strategies for fragment library screening against challenging drug targets using SPR biosensors
- 2024
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Ingår i: SLAS Discovery. - : Elsevier. - 2472-5560 .- 2472-5552. ; :1, s. 40-51
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Tidskriftsartikel (refereegranskat)abstract
- Surface plasmon resonance (SPR) biosensor methods are ideally suited for fragment-based lead discovery. However, generally applicable experimental procedures and detailed protocols are lacking, especially for structurally or physico-chemically challenging targets or when tool compounds are not available. Success depends on accounting for the features of both the target and the chemical library, purposely designing screening experiments for identification and validation of hits with desired specificity and mode-of-action, and availability of orthogonal methods capable of confirming fragment hits. The range of targets and libraries amenable to an SPR biosensor-based approach for identifying hits is considerably expanded by adopting multiplexed strategies, using multiple complementary surfaces or experimental conditions. Here we illustrate principles and multiplexed approaches for using flow-based SPR biosensor systems for screening fragment libraries of different sizes (90 and 1056 compounds) against a selection of challenging targets. It shows strategies for the identification of fragments interacting with 1) large and structurally dynamic targets, represented by acetyl choline binding protein (AChBP), a Cys-loop receptor ligand gated ion channel homologue, 2) targets in multi protein complexes, represented by lysine demethylase 1 and a corepressor (LSD1/CoREST), 3) structurally variable or unstable targets, represented by farnesyl pyrophosphate synthase (FPPS), 4) targets containing intrinsically disordered regions, represented by protein tyrosine phosphatase 1B (PTP1B), and 5) aggregation-prone proteins, represented by an engineered form of human tau (tau K18M). Practical considerations and procedures accounting for the characteristics of the proteins and libraries, and that increase robustness, sensitivity, throughput and versatility are highlighted. The study shows that the challenges for addressing these types of targets is not identification of potentially useful fragments per se, but establishing methods for their validation and evolution into leads.
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| 8. |
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| 10. |
- Hancock, Anne L, et al.
(författare)
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A CTCF-binding silencer regulates the imprinted genes AWT1 and WT1-AS and exhibits sequential epigenetic defects during Wilms' tumourigenesis
- 2007
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 16:3, s. 343-354
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Tidskriftsartikel (refereegranskat)abstract
- We have shown previously that AWT1 and WT1-AS are functionally imprinted in human kidney. In the adult kidney, expression of both transcripts is restricted to the paternal allele, with the silent maternal allele retaining methylation at the WT1 antisense regulatory region (WT1 ARR). Here, we report characterization of the WT1 ARR differentially methylated region and show that it contains a transcriptional silencer element acting on both the AWT1 and WT1-AS promoters. DNA methylation of the silencer results in increased transcriptional repression, and the silencer is also shown to be an in vitro and in vivo target site for the imprinting regulator protein CTCF. Binding of CTCF is methylation-sensitive and limited to the unmethylated silencer. Potentiation of the silencer activity is demonstrated after CTCF protein is knocked down, suggesting a novel silencer-blocking activity for CTCF. We also report assessment of WT1 ARR methylation in developmental and tumour tissues, including the first analysis of Wilms' tumour precursor lesions, nephrogenic rests. Nephrogenic rests show increases in methylation levels relative to foetal kidney and reductions relative to the adult kidney, together with biallelic expression of AWT1 and WT1-AS. Notably, the methylation status of CpG residues within the CTCF target site appears to distinguish monoallelic and biallelic expression states. Our data suggest that failure of methylation spreading at the WT1 ARR early in renal development, followed by imprint erasure, occurs during Wilms' tumourigenesis. We propose a model wherein imprinting defects at chromosome 11p13 may contribute to Wilms' tumourigenesis.
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| 11. |
- Holmgren, Claes, et al.
(författare)
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CpG methylation regulates the Igf2/H19 insulator
- 2001
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Ingår i: Current Biology. - 0960-9822 .- 1879-0445. ; 11:14, s. 1128-1130
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Tidskriftsartikel (refereegranskat)abstract
- The differentially methylated 5'-flank of the mouse H19 gene unidirectionally regulates the communication between enhancer elements and gene promoters and presumably represses maternal Igf2 expression in vivo [1-6]. The specific activation of the paternally inherited Igf2 allele has been proposed to involve methylation-mediated inactivation of the H19 insulator function during male germline development [1-4, 6]. Here, we addressed the role of methylation by inserting a methylated fragment of the H19-imprinting control region (ICR) into a nonmethylated episomal H19 minigene construct, followed by the transfection of ligation mixture into Hep3B cells. Individual clones were expanded and analyzed for genotype, methylation status, chromatin conformation, and insulator function. The results show that the methylated status of the H19 ICR could be propagated for several passages without spreading into the episomal vector. Moreover, the nuclease hypersensitive sites, which are typical for the maternally inherited H19 ICR allele [1], were absent on the methylated ICR, underscoring the suggestion that the methylation mark dictates parent of origin-specific chromatin conformations [1] that involve CTCF [2]. Finally, the insulator function was strongly attenuated in stably maintained episomes. Collectively, these results provide the first experimental support that the H19 insulator function is regulated by CpG methylation.
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| 12. |
- Holmgren, Claes
(författare)
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Epigenetic Regulation of the H19 Chromatin Insulator in Development and Disease
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The coordinated regulation of gene expression must be tightly controlled for normal development to occur. In mammals, this issue is further complicated by the requirement of both the maternal and paternal genomes for normal development, reflecting the fact that a subset of genes are monoallelically expressed depending on parental inheritance, a phenomenon known as genomic imprinting. The imprinted H19 and Igf2 genes are often considered as paradigms of genomic imprinting, since their monoallelic expression patterns are coordinated via a short stretch of sequence upstream of H19, known as the imprinting control region (ICR). This region is differentially methylated, with specific CpG methylation on the paternal allele. It is shown here that the ICR harbours several maternal-specific hypersensitive sites, located in linker regions between positioned nucleosomes. Furthermore, this region functions as an orientation-dependent insulator, that binds the chromatin insulator factor CTCF. The hypothesis that the methylation status of the ICR dictates the activity of the Igf2 gene 90 kb further upstream was confirmed by the demonstration that the insulator function is lost when the ICR is CpG methylated. The ICR has previously been shown to act as a silencer when positioned in a promotor-proximal position. The cause of this silencing was shown to be distance-dependent, suggesting that the silencing features of the ICR depend on a chromatin conformation that renders adjacent sequences inaccessible to the RNA polymerase. These data issue a cautionary note with respect to the interpretation of silencer functions. In several forms of cancer, the normally silent maternal IGF2 gene is expressed, possibly as a result of loss of insulator function at the ICR. The utilisation of CTCF target-sites was analysed in different tumours, and was shown to be highly variable. Methylation analysis showed that potential loss of insulator function and gain of methylation at the maternal ICR did not always correlate with biallelic expression of IGF2. Further investigations uncovered a novel mechanism, in which the activation of the IGF2 promoter was independent of insulator function in some cancers. This thesis shows that the regulation of the imprinted state of Igf2 depends on the formation of an epigenetically regulated chromatin insulator, and that the loss of IGF2 imprinting in human cancer can be attributed to several mechanisms, including a novel mechanism that neutralises chromatin insulator function.
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| 13. |
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| 17. |
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| 19. |
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| 20. |
- van der Ster Wallin, Gisela, et al.
(författare)
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Food selection in anorectics and bulimics : Food items, nutrient content and nutrient density
- 1995
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Ingår i: Journal of the American College of Nutrition (Print). - : Informa UK Limited. - 0731-5724 .- 1541-1087. ; 14:3, s. 271-277
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Tidskriftsartikel (refereegranskat)abstract
- The food selection and nutrient intake were investigated in women with anorexia nervosa, bulimia nervosa and controls. Methods Dietary data was obtained by 24-hour recall, and 7-day recording among eating disordered patients, and by 3-day registration among controls. Results: The intake of energy and nutrients differed from controls, as expected, while there were no differences between anorectics and bulimics in this respect, except for iron. There were only minor differences among the three groups studied with respect to nutrient density. Energy percentages of protein, fat, and carbohydrates, were similar in all groups, but a subdivision of the macronutrients into respective sources showed that bulimics had a lower relative and absolute intake of carbohydrates from bread and cereals than anorectics and controls. Conclusion: Eating disorder patients, despite their marginal food intake, still met the minimum requirement for most nutrients according to the Nordic Nutrient recommendations. Abbreviations: AN = anorexia nervosa, AN/BN = anorectic bulimics, BMI = body mass index, BN = bulimia nervosa, DSM-III-R = Diagnostic and Statistical Manual of Mental Disorders, ED = eating disorder, NNR = Nordic Nutrient Recommendation
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| 21. |
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| 22. |
- Vrethem, Magnus, et al.
(författare)
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Correlation between dynamic posturography, clinical investigation, and neurography in patients with polyneuropathy
- 1991
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Ingår i: Journal for Oto-Rhino-Laryngology. - : S. Karger AG. - 0301-1569 .- 1423-0275. ; 53:5, s. 294-298
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic posturography (PG) is a new objective method to study functional performance in diseases affecting balance. It measures muscle response latencies and sway angles to standardized alterations of a moveable platform and moveable surroundings. Twenty-eight patients with polyneuropathy (PN) were studied by clinical investigation, vibrametry, neurography, and dynamic PG. The results of dynamic PG and vibrametry were compared with those of 29 healthy controls. In the patients with PN, clinical scores correlated to the latencies of the muscle response when the platform was suddenly moved forward, and to equilibrium performance (sway angles) in dynamic PG test conditions with eyes closed and the platform either stable or ‘sway-referenced’. That is, the platform moves in response to the patient’s anterior-posterior sway, creating a disturbed proprioceptive input to the brain. Clinical scores also correlated to the equilibrium performance when both platform and surroundings were sway-referenced. In conclusion dynamic PG, in addition to clinical investigations and neurophysiology, is a valuable and objective method for estimating the equilibrium performance in patients with PN.
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| 23. |
- Zdolsek, Joachim, et al.
(författare)
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Circulatory arrest in late pregnancy : caesarean section a vital decision for both mother and child
- 2009
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley-Blackwell. - 0001-5172 .- 1399-6576. ; 53:6, s. 828-829
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Tidskriftsartikel (refereegranskat)abstract
- Circulatory arrest during pregnancy is extremely rare and there should be a well-planned strategy for its management in all hospitals. To consider the priority of the mothers life over the childs and an unwarranted pre-term delivery may lead to hesitancy and uncertainty and jeopardize both of them. In these situations, speed is a priority. Cardiopulmonary resuscitation should commence immediately. The anaesthesiologist should be well aware of the possible advantage of a caesarean section. Even if the obstetrician is responsible for the decision to perform the operation, the anaesthesiologist should strongly support the action. An emergency caesarean kit with the essential surgical instruments should be immediately available in every labour ward and emergency department.
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| 24. |
- Ödkvist, L. M., et al.
(författare)
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Dynamic posturography in polyneuropathy
- 1992
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Ingår i: Diagnostic procedures and imaging techniques used in neurootology. - Hamburg : Edition M + P. - 3922326366 ; , s. 167-172
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Konferensbidrag (refereegranskat)
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