| 1. |
- Hansen, Jacob B, et al.
(författare)
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Retinoblastoma protein functions as a molecular switch determining white versus brown adipocyte differentiation.
- 2004
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 101:12, s. 4112-7
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Tidskriftsartikel (refereegranskat)abstract
- Adipocyte precursor cells give raise to two major cell populations with different physiological roles: white and brown adipocytes. Here we demonstrate that the retinoblastoma protein (pRB) regulates white vs. brown adipocyte differentiation. Functional inactivation of pRB in wild-type mouse embryo fibroblasts (MEFs) and white preadipocytes by expression of simian virus 40 large T antigen results in the expression of the brown fat-specific uncoupling protein 1 (UCP-1) in the adipose state. Retinoblastoma gene-deficient (Rb-/-) MEFs and stem cells, but not the corresponding wild-type cells, differentiate into adipocytes with a gene expression pattern and mitochondria content resembling brown adipose tissue. pRB-deficient MEFs exhibit an increased expression of the Forkhead transcription factor Foxc2 and its target gene cAMP-dependent protein kinase regulatory subunit RIalpha, resulting in increased cAMP sensitivity. Suppression of cAMP-dependent protein kinase activity in Rb(-/-)MEFs blocked the brown adipocyte-like gene expression pattern without affecting differentiation per se. Immunohistochemical studies revealed that pRB is present in the nuclei of white but not brown adipocyte precursor cells at a developmental stage where both cell types begin to accumulate lipid and brown adipocytes express UCP-1. Furthermore, pRB rapidly undergoes phosphorylation upon cold-induced neodifferentiation and up-regulation of UCP-1 expression in brown adipose tissue. Finally, down-regulation of pRB expression accompanies transdifferentiation of white into brown adipocytes in response to beta3-adrenergic receptor agonist treatment. We propose that pRB acts as a molecular switch determining white vs. brown adipogenesis, suggesting a previously uncharacterized function of this key cell cycle regulator in adipocyte lineage commitment and differentiation.
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| 2. |
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| 3. |
- Ahmadian, Afshin, et al.
(författare)
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Genotyping by apyrase-mediated allele-specific extension
- 2001
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 29:24
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Tidskriftsartikel (refereegranskat)abstract
- This report describes a single-step extension approach suitable for high-throughput single-nucleotide polymorphism typing applications. The method relies on extension of paired allele-specific primers and we demonstrate that the reaction kinetics were slower for mismatched configurations compared with matched configurations. In our approach we employ apyrase, a nucleotide degrading enzyme, to allow accurate discrimination between matched and mismatched primer-template configurations. This apyrase-mediated allele-specific extension (AMASE) protocol allows incorporation of nucleotides when the reaction kinetics are fast (matched 3'-end primer) but degrades the nucleotides before extension when the reaction kinetics are slow (mismatched 3'-end primer). Thus, AMASE circumvents the major limitation of previous allele-specific extension assays in which slow reaction kinetics will still give rise to extension products from mismatched 3'-end primers, hindering proper discrimination. It thus represents a significant improvement of the allele-extension method. AMASE was evaluated by a bioluminometric assay in which successful incorporation of unmodified nucleotides is monitored in real-time using an enzymatic cascade.
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| 4. |
- Blaudez, D., et al.
(författare)
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Differential responses of ectomycorrhizal fungi to heavy metals in vitro
- 2000
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Ingår i: Mycological Research. - : Elsevier. - 0953-7562 .- 1469-8102. ; 104:11, s. 1366-1371
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-nine ectomycorrhizal isolates of Paxillus involutus, Pisolithus tinctorius, Suillus bovinus, S. luteus and S. variegatus were tested on cadmium, copper, nickel and zinc amended media to determine their in vitro tolerance, measured as inhibition of biomass production. Twenty-one isolates were from heavy metal polluted sites, whereas the others were from non-contaminated soils. There was a strong interspecific variation in metal tolerance. S. luteus, S. variegatus and P. tinctorius were more tolerant of Cu, Cd and Zn when compared with P. involutus, whereas the reverse was true for Ni. A high intraspecific heterogeneity in metal tolerance was also found. EC50 values for isolates originating from polluted sites were not statistically different from EC50 values for isolates originating from non-contaminated sites. The findings are discussed in relation to the potential benefits of ectomycorrhizal fungi in protecting their host plants from metal contamination.
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| 5. |
- Hennemuth-Oberle, B., Rutgersson, A., Omstedt, A., Bumke, K., Clemens, M., Jacob, D. and Smedman, A.
(författare)
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: Net precipitation over the Baltic Sea for one year using several methods.
- 2003
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Ingår i: Tellus. ; 55A
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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| 6. |
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| 7. |
- Magnuson, Ann, et al.
(författare)
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High-valent Ruthenium-Manganese Complexes for Solar Energy Production.
- 2001
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Ingår i: PS2001 Proceedings.
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Konferensbidrag (refereegranskat)abstract
- We present progress in the development of artificial photosynthesis, as a means to harvesting and storage of solar energy. The plan is to compose molecular systems that combine known photochemistry with emerging functional model compounds. A photochemical device for solar energy conversion contains a photosensitizer, an electron acceptor system and a donor system that prevents charge recombination. Our goal is to utilize water as sacrificial electron donor, which will allow a net production of reducing equivalents, and the ultimate production of fuel. The only light-driven molecular catalyst for water oxidation exists in Photosystem II (PSII), which has a tetranuclear Mn-cluster in the active site. Here we present several Mn-compounds, that we have developed for the purpose of creating water-oxidizing catalysts. Our idea is to link Ru-tris(bipyridine) derivatives, which mimicks the function of the primary donor in PS II, with manganese complexes, mimicking the tetra-Mn cluster on the PSII donor side. We have constructed a number of heteronuclear complexes, containing a Ru-photosensitizer and various Mn-complexes. The compounds have been characterized with regards to their photophysical and photochemical properties, redox potentials and structure. The most promising compounds are capable of undergoing several electron transfers from the Mn-complex to the photosensitizer, leaving 3 to 4 oxidizing equivalents on the Mn. In the latest development, we have constructed ligands that stabilize higher oxidation states in Mn, in order to promote formation of Mn(V) which many believes is an intermediate in the water oxidation mechanism.
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| 8. |
- Magnusson, V., et al.
(författare)
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Both risk alleles for Fc gamma RIIA and Fc gamma RIIIA are susceptibility factors for SLE : a unifying hypothesis
- 2004
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Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 5:2, s. 130-137
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to analyze in families with SLE for the presence of linkage and the structure and transmission of haplotypes containing alleles for the low-affinity Fcgamma receptors. The Fcgamma receptor polymorphisms FcgammaRIIA-131R/H, FcgammaRIIIA176F/ V and FcgammaRIIIB-NA1/2 and a polymorphism in the FcgammaRIIB gene were genotyped with RFLP, allele-specific PCR or pyrosequencing. Individual SNPs and haplotypes were tested for linkage in multicase families and for association using contingency tables, transmission disequilibrium test and affected family-based control groups in Swedish and Mexican single-case families. No linkage or association could be detected using the FcgammaR polymorphisms in the multicase families. However, an association was found for both FcgammaRIIA-131R and IIIA-176F alleles in the single-case families, but not for IIIB or IIB. Allelic association to SLE was found for a haplotype that included both risk alleles, but not in haplotypes where only one or the other was present. We propose that FcgammaRIIA-131R and FcgammaRIIIA-176F are both risk alleles for SLE transmitted primarily, but not exclusively on a single major haplotype that behaves functionally in a situation similar to that of compound heterozygozity.
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| 9. |
- Sabounchei, J. S., et al.
(författare)
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Rhodium complexes containing O-bonded NHxMe2-xCHO (x=0, 1, 2) : X-ray structure of Rh(PPh3)(3)(OCHNHMe) CIO4
- 2001
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Ingår i: Helvetica Chimica Acta. - 0018-019X .- 1522-2675. ; 84:10, s. 3075-3083
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Tidskriftsartikel (refereegranskat)abstract
- Displacement of norbornadiene (nbd; bicyclo[2.2.1]hepta-2,5-diene) from [Rh(PPh3)(2)(nbd)]ClO4 by hydrogenation in the presence of PPh3 and formamide or Me-substituted derivatives, results in the formation of O-bonded formamide complexes [Rh(PPh3)(3)(OCHNHxMe2-x)]ClO4 (x=0, 1, 2) rather than N-bonded derivatives. These have been characterised by spectroscopic measurements and, in the case of [Rh(PPh3)(3)(OCHNHMe)]ClO4, by X-ray crystallography. All undergo oxidative addition with H-2, and the rates of ligand exchange in the Rh-I and Rh-III complexes have been determined by magnetisation-transfer measurements.
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| 10. |
- Sundström, Johan, et al.
(författare)
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Plasma homocysteine, hypertension incidence, and blood pressure tracking : the Framingham Heart Study.
- 2003
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Ingår i: Hypertension. - 1524-4563. ; 42:6, s. 1100-5
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Tidskriftsartikel (refereegranskat)abstract
- Plasma homocysteine is cross-sectionally associated with blood pressure in large, community-based studies. It is unknown whether elevated plasma homocysteine predicts hypertension incidence. We investigated the relations of baseline plasma total homocysteine levels to hypertension incidence and blood pressure tracking in 2104 Framingham Heart Study participants (mean age, 57 years; 58% women), who were free of hypertension, myocardial infarction, heart failure, atrial fibrillation, or renal failure at baseline. Baseline mean+/-SD plasma homocysteine was 10.1+/-3.7 micromol/L. On follow-up 4 years from baseline, 360 persons (17.1%) had developed hypertension, and 878 persons (41.7%) had progressed to a higher blood pressure stage. In unadjusted analyses, a 1-SD higher log homocysteine value was associated with increased odds of developing hypertension (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.05 to 1.32) and increased odds of blood pressure progression (OR, 1.17; 95% CI, 1.07 to 1.27). The relations of plasma homocysteine to the incidence of hypertension or blood pressure progression were statistically nonsignificant in age- and sex-adjusted logistic regression models (OR, 0.98; 95% CI, 0.87 to 1.11 and OR, 1.05; 95% CI, 0.96 to 1.16, respectively) and in multivariable models adjusted for age, sex, body mass index, diabetes, interim weight change, smoking, serum creatinine, baseline blood pressure, and blood pressure category (OR, 0.92; 95% CI, 0.81 to 1.06 and OR, 1.07; 95% CI, 0.97 to 1.18, respectively). In conclusion, we found no major relation of baseline plasma homocysteine levels to hypertension incidence or longitudinal blood pressure progression in a large, community-based cohort of nonhypertensive individuals after adjustment for age, sex, and other important covariates.
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