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Copenhagen, Denmark

Krustrup P.,Copenhagen University | Ortenblad N.,University of Southern Denmark | Nielsen J.,Copenhagen University | Nybo L.,Copenhagen University | And 6 more authors.
European Journal of Applied Physiology | Year: 2011

The aim of this study was to examine maximal voluntary knee-extensor contraction force (MVC force), sarcoplasmic reticulum (SR) function and muscle glycogen levels in the days after a high-level soccer game when players ingested an optimised diet. Seven high-level male soccer players had a vastus lateralis muscle biopsy and a blood sample collected in a control situation and at 0, 24, 48 and 72 h after a competitive soccer game. MVC force, SR function, muscle glycogen, muscle soreness and plasma myoglobin were measured. MVC force sustained over 1 s was 11 and 10% lower (P < 0.05) after 0 and 24 h, respectively, compared with control. The rate of SR Ca 2+ uptake at 800 nM [Ca 2+] free was lower (P < 0.05) after 0 h (2.5 μmol Ca 2+ g prot -1 min -1) than for all other time points (24 h: 5.1 μmol Ca 2+ g prot -1 min -1). However, SR Ca 2+ release rate was not aVected. Plasma myoglobin was sixfold higher (P < 0.05) immediately after the game, but normalised 24 h after the game. Quadriceps muscle soreness (0-10 VASscale) was higher (P < 0.05) after 0 h (3.6), 24 h (1.8), 48 h (1.1) and 72 h (1.4) compared with control (0.1). Muscle glycogen was 57 and 27% lower (P < 0.001) 0 and 24 h after the game compared with control (193 and 328 vs. 449 mmol kg d w -1). In conclusion, maximal voluntary contraction force and SR Ca 2+ uptake were impaired and muscle soreness was elevated after a high-level soccer game, with faster recovery of SR function in comparison with MVC force, soreness and muscle glycogen. © 2011 Springer-Verlag. Source

Haagensen J.A.J.,Stanford University | Regenberg B.,Technical University of Denmark | Regenberg B.,Universitetsparken 13 | Sternberg C.,Technical University of Denmark
Advances in Biochemical Engineering/Biotechnology | Year: 2011

Growing awareness of heterogeneity in cells of microbial populations has emphasized the importance of advanced microscopy for visualization and understanding of the molecular mechanisms underlying cell-to-cell variation. In this review, we highlight some of the recent advances in confocal microscopy, super-resolution optical microscopy (STED, SIM, PALM) as well as atomic force microscopy and Raman spectroscopy. Using examples of bistability in microbial populations as well as biofilm development and differentiation in bacterial and yeast consortia, we demonstrate the importance of microscopy for visualization of variation between cells in phenotypic traits such as gene expression. © Springer-Verlag Berlin Heidelberg 2010. Source

Dalgaard M.D.,Rigshospitalet | Weinhold N.,Technical University of Denmark | Edsgard D.,Technical University of Denmark | Silver J.D.,Copenhagen University | And 19 more authors.
Journal of Medical Genetics | Year: 2012

Background: Testicular dysgenesis syndrome (TDS) is a common disease that links testicular germ cell cancer, cryptorchidism and some cases of hypospadias and male infertility with impaired development of the testis. The incidence of these disorders has increased over the last few decades, and testicular cancer now affects 1% of the Danish and Norwegian male population. Methods: To identify genetic variants that span the four TDS phenotypes, the authors performed a genome-wide association study (GWAS) using Affymetrix Human SNP Array 6.0 to screen 488 patients with symptoms of TDS and 439 selected controls with excellent reproductive health. Furthermore, they developed a novel integrative method that combines GWAS data with other TDSrelevant data types and identified additional TDS markers. The most significant findings were replicated in an independent cohort of 671 Nordic men. Results: Markers located in the region of TGFBR3 and BMP7 showed association with all TDS phenotypes in both the discovery and replication cohorts. An immunohistochemistry investigation confirmed the presence of transforming growth factor β receptor type III (TGFBR3) in peritubular and Leydig cells, in both fetal and adult testis. Single-nucleotide polymorphisms in the KITLG gene showed significant associations, but only with testicular cancer. Conclusions: The association of single-nucleotide polymorphisms in the TGFBR3 and BMP7 genes, which belong to the transforming growth factor β signalling pathway, suggests a role for this pathway in the pathogenesis of TDS. Integrating data from multiple layers can highlight findings in GWAS that are biologically relevant despite having border significance at currently accepted statistical levels. Source

Ossum C.G.,Copenhagen University | Ossum C.G.,Universitetsparken 13 | Lauritsen A.N.,Copenhagen University | Karottki D.G.,Copenhagen University | Hoffmann E.K.,Copenhagen University
Cellular Physiology and Biochemistry | Year: 2011

Hsp70 has the ability to enhance the recovery of stressed cells by its ability to catalyze the reassembly of damaged proteins. Such a chaperoning function is essential for the Hsp70-mediated protection against anoxic stress that causes protein denaturation. We have studied induction of both transcription and translation of Hsp70 during recovery from chemical anoxia and the role of the extracellular signal regulated kinase ERK2 in this induction of Hsp70. 10 mM azide for 30 minutes (chemical anoxia) significantly inhibited the activity of ERK2 (measured as phospho-ERK) but the ERK-2 activity is rapidly increased in a MEK-independen manner, when azide is washed out of the cells. Chemical anoxia and overnight recovery induced Hsp70 expression (analyzed by Western blotting) and this was inhibited by actinomycin D as well as by cycloheximide showing that induction of both translation and transcription was involved. Inhibition of the MAP kinase p38, which was transiently activated during chemical anoxia, had no effect on the increase in Hsp70 expression whereas an inhibitor of reactive oxygen species and inhibition of the phosphatase PP1 and PP2a inhibited the increase in Hsp70 expression. Inhibition of ERK2 by the MEK inhibitor PD98059 resulted in strong inhibition of Hsp70 protein expression and simultaneous stimulation of hsp70 transcription. © 2011 S. Karger AG, Basel. Source

Flyvbjerg H.,Technical University of Denmark | Gudowska-Nowak E.,Marian Smoluchowski Institute of Physics | Gudowska-Nowak E.,Jagiellonian University | Christophersen P.,Neurosearch | Bennekou P.,Universitetsparken 13
Acta Physica Polonica B | Year: 2012

The non-selective voltage-activated cation channel from human red cells, which is activated at depolarizing potentials, has been shown to exhibit counter-clockwise gating hysteresis. Here, we analyze this phenomenon with the simplest possible phenomenological models. Specifically, the hysteresis cycle, including its direction, is reproduced by a model with 2×2 discrete states: the normal open/closed states and two different states of "gate tension". Rates of transitions between the two branches of the hysteresis curve are modeled with single-barrier kinetics by introducing a real-valued "reaction coordinate" parametrizing the protein's conformational change between the two states of gate tension. The resulting scenario suggests a reanalysis of former experiments with NSVDC channels. Source

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