PubMed | Max Planck Institute for Biophysical Chemistry, The Panum Institute, University of Kaiserslautern and University of Aarhus
Type: Journal Article | Journal: Structure (London, England : 1993) | Year: 2015
Aquaporin 4 (AQP4) is a transmembrane protein from the aquaporin family and is the predominant water channel in the mammalian brain. The regulation of permeability of this protein could be of potential therapeutic use to treat various forms of damage to the nervous tissue. In this work, based on data obtained from in silico and in vitro studies, a pH sensitivity that regulates the osmotic water permeability of AQP4 is demonstrated. The results indicate that AQP4 has increased water permeability at conditions of low pH in atomistic computer simulations and experiments carried out on Xenopus oocytes expressing AQP4. With molecular dynamics simulations, this effect was traced to a histidine residue (H95) located in the cytoplasmic lumen of AQP4. A mutant form of AQP4, in which H95 was replaced with an alanine (H95A), loses sensitivity to cytoplasmic pH changes in in vitro osmotic water permeability, thereby substantiating the in silico work.
Wiese S.S.,The Panum Institute |
Mortensen C.,Hvidovre Hospital |
Bendtsen F.,Hvidovre Hospital
Danish Medical Bulletin | Year: 2011
INTRODUCTION: The relevance of needle type and ultrasound guidance in connection with complications and technical problems in paracentesis in cirrhotic patients has only been sparsely described. The aim of this study was to evaluate paracentesis in cirrhotic patients with refractory ascites, focusing on technique, complications, amount of ascites drained and prognosis. MATERIAL AND METHODS: This was a retrospective study based on 51 cirrhotic patients with refractory ascites undergoing paracentesis. A total of 209 paracenteses were performed using a pigtail catheter and an intravenous catheter. Ultrasound-guided puncture or no ultrasound-guided punctured were compared with regard to amount of drained ascites, technical problems and complications both immediate and within a week of the procedure. The impact of coagulopathy was also investigated. RESULTS: 12% immediate and 5% late complications occurred, most of which were minor. No significant differences in the frequency of complications were found when comparing a pigtail to an intravenous catheter (8% versus 21%, OR = 2.81 95% CI (0.86; 9.13)), nor did the amount of drained ascites differ significantly. Ultrasound guidance did not significantly decrease the frequency of complications (7% versus 9%, OR 1.34 95% CI (0.37; 4.84)). Coagulopathy did not significantly affect the risk of complications. CONCLUSION: Paracentesis in patients with cirrhosis is associated with a low frequency of serious complications, regardless of the technique deployed. Although the material is of limited size, it appears that coagulopathy does not increase the risk of complications following this procedure.
Husu E.,Copenhagen University |
Hove H.D.,Copenhagen University |
Farholt S.,Aarhus University Hospital |
Bille M.,Copenhagen University |
And 5 more authors.
Clinical Genetics | Year: 2013
CHARGE (coloboma of the eye, heart defects, choanal atresia, retarded growth and development, genital hypoplasia and ear anomalies and/or hearing loss) syndrome is a rare genetic, multiple-malformation syndrome. About 80% of patients with a clinical diagnose, have a mutation or a deletion in the gene encoding chromodomain helicase DNA-binding protein 7 (CHD7). Genotype-phenotype correlation is only partly known. In this nationwide study, phenotypic characteristics of 18 Danish CHD7 mutation positive CHARGE individuals (N = 18) are presented. We studied patient records, clinical photographs, computed tomography, and magnetic resonance imaging (MRI). Information was not available for all traits in all subjects. Therefore, the results are presented as fractions. The following prevalence of cardinal symptoms were found: coloboma, 16/17; heart defects, 14/18; choanal atresia, 7/17; retarded growth and development, 11/13; genital abnormalities, 5/18; ear anomalies, 15/17 and sensorineural hearing loss, 14/15. Vestibular dysfunction (10/13) and swallowing problems (12/15) were other frequent cranial nerve dysfunctions. Three-dimensional reconstructions of MRI scans showed temporal bone abnormalities in >85%. CHARGE syndrome present a broad phenotypic spectrum, although some clinical features are more frequently occurring than others. Here, we suggest that genetic testing for CHD7 mutation should be considered in neonates with a specific combination of several clinical symptoms. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.
Zhang Q.D.,University Paris Diderot |
March G.,University Paris Diderot |
Noel V.,University Paris Diderot |
Piro B.,University Paris Diderot |
And 9 more authors.
Biosensors and Bioelectronics | Year: 2012
We report a signal-on, label-free and reagentless electrochemical DNA biosensor, based on a mixed self-assembled monolayer of thiolated hydroxynaphthoquinone and thiolated oligonucleotide. Electrochemical changes resulting from hybridization were evidenced with oligonucleotide targets (as models), as well as with polymerase chain reaction (PCR) products related to different lineages of Mycobacterium tuberculosis strains. With pure oligonucleotides, this system achieves high sensitivity (~300. pM of DNA target, i.e. 30. fmol in a 100μL sample) and excellent selectivity, allowing to detect a single mismatch on a sequence of 20 bases. With PCR products, current changes are specific to the bacterial strain from which the PCR fragment is produced. In addition, the sensor response is of the signal-on type, giving a positive signal change upon hybridization, and therefore does not suffer from false positive responses due to non-specific adsorption of DNA. © 2011 Elsevier B.V.
Hoang T.,Statens Serum Institute |
Agger E.M.,Statens Serum Institute |
Cassidy J.P.,University College Dublin |
Christensen J.P.,The Panum Institute |
Andersen P.,Statens Serum Institute
Infection and Immunity | Year: 2015
Protein energy malnutrition (PEM) increases susceptibility to infectious diseases, including tuberculosis (TB), but it is not clear how PEM influences vaccine-promoted immunity to TB. We demonstrate that PEM during low-level steady-state TB infection in a mouse model results in rapid relapse of Mycobacterium tuberculosis, as well as increased pathology, in both Mycobacterium bovis BCG-vaccinated and unvaccinated animals. PEM did not change the overall numbers of CD4 T cells in BCG-vaccinated animals but resulted in an almost complete loss of antigen-specific cytokine production. Furthermore, there was a change in cytokine expression characterized by a gradual loss of multifunctional antigen-specific CD4 T cells and an increased proportion of effector cells expressing gamma interferon and tumor necrosis factor alpha (IFN-γ+ TNF-α+ and IFN-γ+ cells). PEM during M. tuberculosis infection completely blocked the protection afforded by the H56-CAF01 subunit vaccine, and this was associated with a very substantial loss of the interleukin-2-positive memory CD4 T cells promoted by this vaccine. Similarly, PEM during the vaccination phase markedly reduced the H56-CAF01 vaccine response, influencing all cytokine-producing CD4 T cell subsets, with the exception of CD4 T cells positive for TNF-α only. Importantly, this impairment was reversible and resupplementation of protein during infection rescued both the vaccine-promoted T cell response and the protective effect of the vaccine against M. tuberculosis infection. © 2015, American Society for Microbiology.
PubMed | The Panum Institute, University College Dublin and Statens Serum Institute
Type: Journal Article | Journal: Infection and immunity | Year: 2015
Protein energy malnutrition (PEM) increases susceptibility to infectious diseases, including tuberculosis (TB), but it is not clear how PEM influences vaccine-promoted immunity to TB. We demonstrate that PEM during low-level steady-state TB infection in a mouse model results in rapid relapse of Mycobacterium tuberculosis, as well as increased pathology, in both Mycobacterium bovis BCG-vaccinated and unvaccinated animals. PEM did not change the overall numbers of CD4 T cells in BCG-vaccinated animals but resulted in an almost complete loss of antigen-specific cytokine production. Furthermore, there was a change in cytokine expression characterized by a gradual loss of multifunctional antigen-specific CD4 T cells and an increased proportion of effector cells expressing gamma interferon and tumor necrosis factor alpha (IFN-(+) TNF-(+) and IFN-(+) cells). PEM during M. tuberculosis infection completely blocked the protection afforded by the H56-CAF01 subunit vaccine, and this was associated with a very substantial loss of the interleukin-2-positive memory CD4 T cells promoted by this vaccine. Similarly, PEM during the vaccination phase markedly reduced the H56-CAF01 vaccine response, influencing all cytokine-producing CD4 T cell subsets, with the exception of CD4 T cells positive for TNF- only. Importantly, this impairment was reversible and resupplementation of protein during infection rescued both the vaccine-promoted T cell response and the protective effect of the vaccine against M. tuberculosis infection.
Krogsgaard M.R.,Copenhagen University |
Fischer-Rasmussen T.,Copenhagen University |
Dyhre-Poulsen P.,The Panum Institute
Journal of Electromyography and Kinesiology | Year: 2011
Cruciate ligaments provide sensory information that cause excitatory as well as inhibitory effects to the activity of the muscles around the knee. The aim of the study was to determine whether these muscular reflexes are reestablished after anterior cruciate ligament (ACL) re-construction. Wire electrodes were inserted during arthroscopy into the normal posterior cruciate ligament (PCL) and the reconstructed ACL in 11 patients who had a successful ACL re-construction 8. months to 12. years earlier. After the anesthesia had subsided, the PCL was stimulated electrically through the electrodes and the sensory threshold was determined. Stimulus amplitudes were increased to 1.5-2.0 times the sensory threshold, and inhibitory reflexes could be elicited from PCL in the quadriceps during active extension and in the hamstrings muscles during active flexion in all patients. Subsequently the ACL re-constructions were stimulated. The sensory threshold was 3.4 times higher in the ACL than in the PCL. Stimulus amplitudes were increased to 1.5-2.0 times the sensory threshold, and a typical inhibitory reflex could be elicited in 9 patients. The latency was the same as for the reflex from the PCL. The stimulus amplitudes necessary to elicit reflexes from the ACL re-constructions were 2, 9 times higher than amplitudes that elicited reflexes from the PCL. Sensation and afferent reflex activity required a much stronger stimulus in the ACL graft compared to normal PCL. We suggest that the reason for this is that the ACL grafts were not reinnervated, and that the reflexes were elicited by spread of stimulus current to the PCL. © 2010 Elsevier Ltd.
Birkedal H.,The Panum Institute |
Nielsen P.E.,The Panum Institute |
Nielsen P.E.,Copenhagen University
Artificial DNA: PNA and XNA | Year: 2011
Gene correction activation effects of a small series of triplex forming peptide nucleic acid (PNA) covalently conjugated to the DNA interacting ligands psoralen, chlorambucil and camptothecin targeted proximal to a stop codon mutation in an eGFP reporter gene were studied. A 15-mer homopyrimidine PNA conjugated to the topoisomerase I inhibitor camptothecin was found to increase the frequency of repair domain mediated gene correctional events of the eGFP reporter in an in vitro heLa cell nuclear extract assay, whereas PNA psoralen or chlorambucil conjugates both of which form covalent and also interstrand crosslinked adducts with dsDNA dramatically decreased the frequency of targeted repair/correction. The PNA conjugates were also studied in mammalian cell lines upon transfection of PNA bound eGFP reporter vector and scoring repair of the eGFP gene by FAcs analysis of functional eGFP expression. Consistent with the extract experiments, treatment with adduct forming PNA conjugates (psoralen and chlorambucil) resulted in a decrease in background correction frequencies in transiently transfected cells, whereas unmodified PNA or the PNA-camptothecin conjugate had little or no effect. These results suggest that simple triplex forming PNAs have little effect on proximal gene correctional events whereas PNA conjugates capable of forming DNA adducts and interstrand crosslinks are strong inhibitors. Most interestingly the PNA conjugated to the topoisomerase inhibitor, camptothecin enhanced repair in nuclear extract. Thus the effects and use of camptothecin conjugates in gene targeted repair merit further studies. © 2011 Landes Bioscience.
Silahtaroglu A.N.,The Panum Institute
Methods in molecular biology (Clifton, N.J.) | Year: 2010
MicroRNAs (miRNAs) are small ( approximately 22 nt) noncoding RNA molecules that regulate the expression of protein coding genes either by cleavage or translational repression. miRNAs comprise one of the most abundant classes of gene regulatory molecules in multicellular organisms. Yet, the function of miRNAs at the tissue, cell, and subcellular levels is still to be explored. Especially, determining spatial and temporal expression of miRNAs has been a challenge due to their short size and low expression. This protocol describes a fast and effective method for detection of miRNAs in frozen tissue sections using fluorescence in situ hybridization. The method employs the unique recognition power of locked nucleic acids as probes together with enhanced detection power of the tyramide signal amplification system for detection of miRNAs in frozen tissues of human and animal origin within a single day.
PubMed | the Panum Institute and Copenhagen University
Type: Journal Article | Journal: Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery | Year: 2016
GLP-1 secretion in response to meals is dramatically increased after gastric bypass operations. GLP-1 is a powerful insulinotropic and anorectic hormone, and analogs of GLP-1 are widely used for the treatment of diabetes and recently approved also for obesity treatment. It is, therefore, reasonable to assume that the exaggerated GLP-1 secretion contributes to the antidiabetic and anorectic effects of gastric bypass. Indeed, human experiments with the GLP-1 receptor antagonist, Exendin 9-39, have shown that the improved insulin secretion, which is responsible for part of the antidiabetic effect of the operation, is reduced and or abolished after GLP-1 receptor blockade. Also the postoperative improvement of glucose tolerance is eliminated and or reduced by the antagonist, pointing to a key role for the exaggerated GLP-1 secretion. Indeed, there is evidence that the exaggerated GLP-1 secretion is also responsible for postprandial hypoglycemia sometimes observed after bypass. Other operations (biliopancreatic-diversion and or sleeve gastrectomy) appear to involve different and/or additional mechanisms, and so does experimental bariatric surgery in rodents. However, unlike bypass surgery in humans, the rodent operations are generally associated with increased energy metabolism pointing to an entirely different mechanism of action in the animals.