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Tahirbegi IB, Pardo WA, Alvira M, Mir M, Samitier J. Amyloid Aβ 42, a promoter of magnetite nanoparticle formation in Alzheimer's disease. Nanotechnology 2016; 27:465102. [PMID: 27734811 DOI: 10.1088/0957-4484/27/46/465102] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The accumulation of iron oxides-mainly magnetite-with amyloid peptide is a key process in the development of Alzheimer's disease (AD). However, the mechanism for biogeneration of magnetite inside the brain of someone with AD is still unclear. The iron-storing protein ferritin has been identified as the main magnetite-storing molecule. However, accumulations of magnetite in AD are not correlated with an increase in ferritin, leaving this question unresolved. Here we demonstrate the key role of amyloid peptide Aβ 42, one of the main hallmarks of AD, in the generation of magnetite nanoparticles in the absence of ferritin. The capacity of amyloid peptide to bind and concentrate iron hydroxides, the basis for the formation of magnetite, benefits the spontaneous synthesis of these nanoparticles, even under unfavorable conditions for their formation. Using scanning and transmission electron microscopy, electron energy loss spectroscopy and magnetic force microscopy we characterized the capacity of amyloid peptide Aβ 42 to promote magnetite formation.
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Affiliation(s)
- Islam Bogachan Tahirbegi
- Nanobioengineering Laboratory, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac, 10-12, Barcelona 08028, Spain. Department of Electronics, University of Barcelona (UB), Martí i Franquès, 1, Barcelona 08028, Spain
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2
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Miguel S, Alvira M, Farré M, Risco E, Cabrera E, Zabalegui A. Quality of life and associated factors in older people with dementia living in long-term institutional care and home care. Eur Geriatr Med 2016. [DOI: 10.1016/j.eurger.2016.01.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Galán T, Prieto-Simón B, Alvira M, Eritja R, Götz G, Bäuerle P, Samitier J. Label-free electrochemical DNA sensor using "click"-functionalized PEDOT electrodes. Biosens Bioelectron 2015. [PMID: 26210592 DOI: 10.1016/j.bios.2015.07.037] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Here we describe a label-free electrochemical DNA sensor based on poly(3,4-ethylenedioxythiophene)-modified (PEDOT-modified) electrodes. An acetylene-terminated DNA probe, complementary to a specific "Hepatitis C" virus sequence, was immobilized onto azido-derivatized conducting PEDOT electrodes using "click" chemistry. DNA hybridization was then detected by differential pulse voltammetry, evaluating the changes in the electrochemical properties of the polymer produced by the recognition event. A limit of detection of 0.13 nM was achieved using this highly selective PEDOT-based genosensor, without the need for labeling techniques or microelectrode fabrication processes. These results are promising for the development of label-free and reagentless DNA hybridization sensors based on conducting polymeric substrates. Biosensors can be easily prepared using any DNA sequence containing an alkyne moiety. The data presented here reveal the potential of this DNA sensor for diagnostic applications in the screening of diseases, such as "Hepatitis C", and genetic mutations.
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Affiliation(s)
- Teresa Galán
- Nanobioengineering group, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac 15-21, Barcelona 08028, Spain; Electronics Department, University of Barcelona (UB), Martí i Franquès 1-11, Barcelona 08028, Spain.
| | | | - Margarita Alvira
- Nanobioengineering group, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac 15-21, Barcelona 08028, Spain; Fundació Bosch i Gimpera, Baldiri Reixac, 4-8, Parc Científic Barcelona, Torre D, 08028 Barcelona, Spain.
| | - Ramón Eritja
- Networking Biomedical Research Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18-26, Barcelona 08034, Spain.
| | - Günther Götz
- Institute of Organic Chemistry II and New Materials, University Ulm, Albert-Einstein-Allee 11, d-89081 Ulm, Germany
| | - Peter Bäuerle
- Institute of Organic Chemistry II and New Materials, University Ulm, Albert-Einstein-Allee 11, d-89081 Ulm, Germany.
| | - Josep Samitier
- Nanobioengineering group, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac 15-21, Barcelona 08028, Spain; Networking Biomedical Research Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); Electronics Department, University of Barcelona (UB), Martí i Franquès 1-11, Barcelona 08028, Spain.
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Tahirbegi IB, Alvira M, Mir M, Samitier J. Simple and fast method for fabrication of endoscopic implantable sensor arrays. Sensors (Basel) 2014; 14:11416-26. [PMID: 24971473 PMCID: PMC4168460 DOI: 10.3390/s140711416] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/10/2014] [Accepted: 06/20/2014] [Indexed: 01/21/2023]
Abstract
Here we have developed a simple method for the fabrication of disposable implantable all-solid-state ion-selective electrodes (ISE) in an array format without using complex fabrication equipment or clean room facilities. The electrodes were designed in a needle shape instead of planar electrodes for a full contact with the tissue. The needle-shape platform comprises 12 metallic pins which were functionalized with conductive inks and ISE membranes. The modified microelectrodes were characterized with cyclic voltammetry, scanning electron microscope (SEM), and optical interferometry. The surface area and roughness factor of each microelectrode were determined and reproducible values were obtained for all the microelectrodes on the array. In this work, the microelectrodes were modified with membranes for the detection of pH and nitrate ions to prove the reliability of the fabricated sensor array platform adapted to an endoscope.
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Affiliation(s)
- I Bogachan Tahirbegi
- Nanobioengineering Laboratory, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac, 10-12, Barcelona 08028, Spain.
| | - Margarita Alvira
- Nanobioengineering Laboratory, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac, 10-12, Barcelona 08028, Spain.
| | - Mònica Mir
- Nanobioengineering Laboratory, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac, 10-12, Barcelona 08028, Spain.
| | - Josep Samitier
- Nanobioengineering Laboratory, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac, 10-12, Barcelona 08028, Spain.
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Ferreira R, Alvira M, Aviñó A, Gómez-Pinto I, González C, Gabelica V, Eritja R. Synthesis and structural characterization of stable branched DNA g-quadruplexes using the trebler phosphoramidite. ChemistryOpen 2012; 1:106-14. [PMID: 24551498 PMCID: PMC3922461 DOI: 10.1002/open.201200009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Indexed: 01/17/2023] Open
Abstract
Guanine (G)-rich sequences can form a noncanonical four-stranded structure known as the G-quadruplex. G-quadruplex structures are interesting because of their potential biological properties and use in nanosciences. Here, we describe a method to prepare highly stable G-quadruplexes by linking four G-rich DNA strands to form a monomolecular G-quadruplex. In this method, one strand is synthesized first, and then a trebler molecule is added to simultaneously assemble the remaining three strands. This approach allows the introduction of specific modifications in only one of the strands. As a proof of concept, we prepared a quadruplex where one of the chains includes a change in polarity. A hybrid quadruplex is observed in ammonium acetate solutions, whereas in the presence of sodium or potassium, a parallel G-quadruplex structure is formed. In addition to the expected monomolecular quadruplexes, we observed the presence of dimeric G-quadruplex structures. We also applied the method to prepare G-quadruplexes containing a single 8-aminoguanine substitution and found that this single base stabilizes the G-quadruplex structure when located at an internal position.
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Affiliation(s)
- Rubén Ferreira
- Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain)
| | - Margarita Alvira
- Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain)
| | - Anna Aviñó
- Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain)
| | - Irene Gómez-Pinto
- Departmento de Química Física Biológica, Instituto de Química Física 'Rocasolano' CSIC, Serrano 119, 28006 Madrid (Spain)
| | - Carlos González
- Departmento de Química Física Biológica, Instituto de Química Física 'Rocasolano' CSIC, Serrano 119, 28006 Madrid (Spain)
| | - Valérie Gabelica
- Department of Chemistry, University of Liège Allée de la Chimie Building B6c, 4000 Liège (Belgium)
| | - Ramon Eritja
- Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Networking Centre on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) Jordi Girona 18-26, 08034 Barcelona (Spain) ; Department of Chemistry and Molecular Pharmacology, Institute for Research in Biomedicine (IRB Barcelona) Baldiri i Reixac 10, 08028 Barcelona (Spain)
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Honcharenko M, Romanowska J, Alvira M, Jezowska M, Kjellgren M, Edvard Smith CI, Strömberg R. Capping of oligonucleotides with “clickable” m3G-CAPs. RSC Adv 2012. [DOI: 10.1039/c2ra22345g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Wenska M, Alvira M, Steunenberg P, Stenberg Å, Murtola M, Strömberg R. An activated triple bond linker enables 'click' attachment of peptides to oligonucleotides on solid support. Nucleic Acids Res 2011; 39:9047-59. [PMID: 21795380 PMCID: PMC3203603 DOI: 10.1093/nar/gkr603] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 07/05/2011] [Accepted: 07/06/2011] [Indexed: 11/13/2022] Open
Abstract
A general procedure, based on a new activated alkyne linker, for the preparation of peptide-oligonucleotide conjugates (POCs) on solid support has been developed. With this linker, conjugation is effective at room temperature (RT) in millimolar concentration and submicromolar amounts. This is made possible since the use of a readily attachable activated triple bond linker enhances the Cu(I) catalyzed 1,3-dipolar cycloaddition ('click' reaction). The preferred scheme for conjugate preparation involves sequential conjugation to oligonucleotides on solid support of (i) an H-phosphonate-based aminolinker; (ii) the triple bond donor p-(N-propynoylamino)toluic acid (PATA); and (iii) azido-functionalized peptides. The method gives conversion of oligonucleotide to the POC on solid support, and only involves a single purification step after complete assembly. The synthesis is flexible and can be carried out without the need for specific automated synthesizers since it has been designed to utilize commercially available oligonucleotide and peptide derivatives on solid support or in solution. Methodology for the ready conversion of peptides into 'clickable' azidopeptides with the possibility of selecting either N-terminus or C-terminus connection also adds to the flexibility and usability of the method. Examples of synthesis of POCs include conjugates of oligonucleotides with peptides known to be membrane penetrating and nuclear localization signals.
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Affiliation(s)
- Malgorzata Wenska
- Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge, Sweden
| | | | | | | | | | - Roger Strömberg
- Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge, Sweden
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Abstract
DNA Parallel clamps with a polypurine strand linked to a polypyrimidine Hoogsteen strand containing locked nucleic acids bind their corresponding polypyrimidine targets with high affinity.
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Affiliation(s)
- Margarita Alvira
- Institute for Research in Biomedicine, IQAC-CSIC, CIBER-BBN Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Edifici Helix, Baldiri Reixac 15, ES-08028 Barcelona, Spain
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Mazzini S, García-Martin F, Alvira M, Aviñó A, Manning B, Albericio F, Eritja R. Synthesis of oligonucleotide derivatives using ChemMatrix supports. Chem Biodivers 2008; 5:209-18. [PMID: 18205124 DOI: 10.1002/cbdv.200890012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The synthesis of oligonucleotides on poly(ethylene glycol)-based (ChemMatrix) supports was studied. Results show that oligonucleotides can be indeed prepared in good yields using slightly modified synthesis cycles and automated DNA synthesizers. The use of these supports for the synthesis of oligonucleotide-peptide conjugates and for the ligation of oligonucleotides using Cu(+)-catalyzed cycloadition reactions is reported. Moreover, these supports can be used for the preparation of oligonucleotides in anhydrous solvents, followed by hybridization of the complementary sequences in aqueous buffers.
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Affiliation(s)
- Stefania Mazzini
- Institute for Research in Biomedicine, Barcelona Science Park, University of Barcelona, Spain
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Aviñó A, Grimau MG, Alvira M, Eritja R, Gargallo R, Orozco M, González C. Triplex formation using oligonucleotide clamps carrying 8-aminopurines. Nucleosides Nucleotides Nucleic Acids 2008; 26:979-83. [PMID: 18058521 DOI: 10.1080/15257770701508398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The synthesis and properties of triplex-forming DNA clamps carrying 8-aminopurines are described. The stability of triple helices is enhanced by replacing purine bases with 8-aminopurine residues. These enhanced binding properties are used for the specific capture of polypyrimidine RNA/DNA sequences of interest.
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Affiliation(s)
- Anna Aviñó
- Instituto de Biologia Molecular de Barcelona, C.S.I.C., Barcelona, Spain
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11
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Abstract
There is considerable interest in coupling oligonucleotides to molecules and surfaces. Although amino- and thiol-containing oligonucleotides are being successfully used for this purpose, cycloaddition reactions may offer greater advantages due to their higher chemoselectivity and speed. In this study, copper-catalyzed 1,3-dipolar cycloaddition reactions between oligonucleotides carrying azido and alkyne groups are examined. For this purpose, several protocols for the preparation of oligonucleotides carrying these two groups are described. The non-templated chemical ligation of two oligonucleotides via copper-catalyzed [3+2] cycloaddition is described. By solid-phase methodology, oligonucleotides carrying 5'-5' linkages can be obtained in good yields.
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Affiliation(s)
- Margarita Alvira
- Institut de Biologia Molecular de Barcelona-CSIC, CIBER-BBN Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Josep Samitier 1, E-08028 Barcelona
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Kass-Eisler A, Falck-Pedersen E, Elfenbein DH, Alvira M, Buttrick PM, Leinwand LA. The impact of developmental stage, route of administration and the immune system on adenovirus-mediated gene transfer. Gene Ther 1994; 1:395-402. [PMID: 7584105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Important aspects of successful adenovirus gene transfer include the amount and persistence of gene expression, the ability to readminister virus and the localization of virus-directed gene expression to target organs. Our objective in this study was to use a single recombinant adenovirus bearing a quantifiable reporter gene [chloramphenicol acetyltransferase (CAT)] to establish the parameters which define the limits of adenovirus gene expression in a rat model. First, we determined how the route of virus administration affected the amount, duration and distribution of expression in different tissues and in rats of different developmental stages. All routes resulted in infection of all tissues tested. Surprisingly, the most efficient and widespread gene transfer was achieved by intracardiac muscle injection. The high levels of CAT protein that can be produced in a liver (< or = 1.7 mg) or a heart (< or = 196 micrograms) 5 days after infection suggest that the amount of gene product will not be a limitation in the use of adenovirus. Following peak activity at 5 days after infection, a gradual decline of CAT expression was observed in all tissues assayed; by 80 days neither CAT activity nor adenovirus DNA were detectable. In addition, adults could not be boosted by a second administration of virus, presumably due to the presence of high levels of neutralizing antibodies. The limited persistence of gene expression could be circumvented when virus was injected into neonates. Blocking T lymphocyte expansion by cyclosporine enhanced the persistence of CAT gene product over a 25-day period in heart and lung but not in liver compared with control animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A Kass-Eisler
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Falck-Pedersen E, Heinflink M, Alvira M, Nussenzveig DR, Gershengorn MC. Expression of thyrotropin-releasing hormone receptors by adenovirus-mediated gene transfer reveals that thyrotropin-releasing hormone desensitization is cell specific. Mol Pharmacol 1994; 45:684-9. [PMID: 8183247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Biological studies of seven-transmembrane region G protein-coupled receptors have been restricted by available techniques for gene transfer into mammalian cells. We have created a highly efficient adenovirus-based expression vector for the thyrotropin-releasing hormone (TRH) receptor (TRH-R), AdCMVmTRHR, to circumvent difficulties encountered when transient or stable plasmid expression systems are used. We show that infection with AdCMVmTRHR results in fully functional TRH-Rs, which can be expressed in a broad range of mammalian cell types, including those resistant to conventional transient transfection. TRH-Rs can be expressed at high levels, up to 2 x 10(6) receptors/cell. Expression in several cell lines in culture reveals that rapid TRH-R desensitization by TRH and phorbol 12-myristate 13-acetate is cell type specific. The versatility of adenovirus-mediated gene transfer and expression of TRH-Rs not only facilitates in vitro studies of TRH-R biology but also provides a valuable in vivo expression vector capable of extending TRH-R studies to animal model systems.
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Affiliation(s)
- E Falck-Pedersen
- Department of Microbiology, Cornell University Medical College, New York, New York 10021
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Kass-Eisler A, Falck-Pedersen E, Alvira M, Rivera J, Buttrick PM, Wittenberg BA, Cipriani L, Leinwand LA. Quantitative determination of adenovirus-mediated gene delivery to rat cardiac myocytes in vitro and in vivo. Proc Natl Acad Sci U S A 1993; 90:11498-502. [PMID: 8265580 PMCID: PMC48011 DOI: 10.1073/pnas.90.24.11498] [Citation(s) in RCA: 214] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
To optimize the use of modified adenoviruses as vectors for gene delivery to the myocardium, we have characterized infection of cultured fetal and adult rat cardiac myocytes in vitro and of adult cardiac myocytes in vivo by using a replication-defective adenovirus carrying the chloramphenicol acetyltransferase (CAT) reporter gene driven by the cytomegalovirus promoter (AdCMVCATgD). In vitro, virtually all fetal or adult cardiocytes express the CAT gene when infected with 1 plaque-forming unit of virus per cell. CAT enzymatic activity can be detected in these cells as early as 4 hr after infection, reaching near-maximal levels at 48 hr. In fetal cells, CAT expression was maintained without a loss in activity for at least 1 week. Using in vitro studies as a guide, we introduced the AdCMVCATgD virus directly into adult rat myocardium and compared the expression results obtained from virus injection with those obtained by direct injection of pAdCMVCATgD plasmid DNA. The amount of CAT activity resulting from adenovirus infection of the myocardium was orders of magnitude higher than that seen from DNA injection and was proportional to the amount of input virus. Immunostaining for CAT protein in cardiac tissue sections following adenovirus injection demonstrated large numbers of positive cells, reaching nearly 100% of the myocytes in many regions of the heart. Expression of genes introduced by adenovirus peaked at 5 days but was still detectable 55 days following infection. Adenoviruses are therefore a very useful tool for high-efficiency gene transfer into the cardiovascular system.
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Affiliation(s)
- A Kass-Eisler
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461
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Tantravahi J, Alvira M, Falck-Pedersen E. Characterization of the mouse beta maj globin transcription termination region: a spacing sequence is required between the poly(A) signal sequence and multiple downstream termination elements. Mol Cell Biol 1993; 13:578-87. [PMID: 8417354 PMCID: PMC358937 DOI: 10.1128/mcb.13.1.578-587.1993] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
For the majority of mRNA encoding eukaryotic transcription units, there is little or no knowledge of the elements responsible for transcription termination or how they may interact with RNA polymerase. In this report, we have used recombinant adenovirus reporter vectors to characterize the mouse beta maj globin sequence elements that cause transcription termination. Within the globin 3' termination region, we have identified at least three sequence elements which induce significant levels of transcription termination (> 50%). The smallest functionally active element (64% termination) is 69 bp in length. The natural arrangement of these elements results in a cumulative termination which is greater than 90%. Recognition of the termination elements by RNA polymerase II depends on the presence of a functional poly(A) signal sequence. We demonstrate that efficient transcription termination depends on appropriate spacing between the poly(A) signal sequence and the termination element.
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Affiliation(s)
- J Tantravahi
- Department of Microbiology, W. Randolph Hearst Foundation, Cornell University Medical College, New York, New York 10021
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Linnemann CC, Dunn CR, First MR, Alvira M, Schiff GM. Late onset of fatal cytomegalovirus infection after renal transplantation. Primary or reactivation infection? Arch Intern Med 1978; 138:1247-50. [PMID: 209756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cytomegaloviurs (CMV) infections are a recognized problem in the first six months after renal transplantation. Studies have suggested that primary infections produce symptomatic disease, whereas reactivation infections are usually asymptomatic. Two patients are described who developed fatal CMV infections in the second year after transplantation. Both patients had typical CMV disease with fever, pneumonitis, and hepatitis. Results of serologic studies in one patient were characteristic of primary infection, with seroconversion at the time of disease and appearance of specific IgM antibodies. The other patient had a similar antibody response at the time of his illness, but serial antibody tests showed that he had had a transient seroconversion earlier, in the second month after transplanation, that was not associated with clinical symptoms. These patients indicate that CMV infection must be considered in the differential diagnosis of serious febrile illnesses even in the late posttransplantation period and may occur either as the result of primary or reactivation infection. Serologic studies at the time of illness may not allow distinction between the types of infection.
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