University Clinic for Nephrology and Hypertension, Diabetology and Endocrinology

NF-κB transcription factors are retained in the cytoplasm in an inactive form until they are activated and rapidly imported into the nucleus. We identified importin α3 and importin α4 as the main importin α isoforms mediating TNF-α-stimulated NF-κB p50/p65 heterodimer translocation into the nucleus. Importin α3 and α4 are close relatives in the human importin α family. We show that importin α3 isoform also mediates nuclear import of NF-κB p50 homodimer in nonstimulated cells. Importin α3 is shown to directly bind to previously characterized nuclear localization signals (NLSs) of NF-κB p50 and p65 proteins. Importin α molecules are known to have armadillo repeats that constitute the N-terminal and C-terminal NLS binding sites. We demonstrate by site-directed mutagenesis that NF-κB p50 binds to the N-terminal and p65 to the C-terminal NLS binding site of importin α3. In vitro competition experiments and analysis of cellular NF-κB suggest that NF-κB binds to importin α only when it is free of IκBα. The present study demonstrates that the nuclear import of NF-κB is a highly regulated process mediated by a subset of importin α molecules. NF-κB transcription factors are retained in the cytoplasm in an inactive form until they are activated and rapidly imported into the nucleus. We identified importin α3 and importin α4 as the main importin α isoforms mediating TNF-α-stimulated NF-κB p50/p65 heterodimer translocation into the nucleus. Importin α3 and α4 are close relatives in the human importin α family. We show that importin α3 isoform also mediates nuclear import of NF-κB p50 homodimer in nonstimulated cells. Importin α3 is shown to directly bind to previously characterized nuclear localization signals (NLSs) of NF-κB p50 and p65 proteins. Importin α molecules are known to have armadillo repeats that constitute the N-terminal and C-terminal NLS binding sites. We demonstrate by site-directed mutagenesis that NF-κB p50 binds to the N-terminal and p65 to the C-terminal NLS binding site of importin α3. In vitro competition experiments and analysis of cellular NF-κB suggest that NF-κB binds to importin α only when it is free of IκBα. The present study demonstrates that the nuclear import of NF-κB is a highly regulated process mediated by a subset of importin α molecules. NF-κB 1The abbreviations used are: NF-κB, nuclear factor κB; NLS, nuclear localization signal; arm, armadillo motif; TNF-α, tumor necrosis factor-α; LMB, leptomycin B; NES, nuclear export signal; NPC, nuclear pore complex; GST, glutathione S-transferase; FITC, fluorescein isothiocyanate; STAT, signal transducers and activators of transcription. 1The abbreviations used are: NF-κB, nuclear factor κB; NLS, nuclear localization signal; arm, armadillo motif; TNF-α, tumor necrosis factor-α; LMB, leptomycin B; NES, nuclear export signal; NPC, nuclear pore complex; GST, glutathione S-transferase; FITC, fluorescein isothiocyanate; STAT, signal transducers and activators of transcription. p50/p65 transcription factor has a central role in controlling host cell immune and inflammatory responses, cell differentiation, and apoptosis (1Baeuerle P.A. Baltimore D. Cell. 1996; 87: 13-20Abstract Full Text Full Text PDF PubMed Scopus (2919) Google Scholar, 2Ghosh S. May M.J. Kopp E.B. Annu. Rev. Immunol. 1998; 16: 225-260Crossref PubMed Scopus (4585) Google Scholar). Dysregulation of NF-κB has been associated with several common diseases such as cancer and diabetes (3Baldwin Jr., A.S. J. Clin. Investig. 2001; 107: 3-6Crossref PubMed Google Scholar). Cytoplasmic NF-κB can be rapidly activated by various physiological and nonphysiological stimuli such as cytokines, growth factors, bacterial or viral infection and UV irradiation. Activation of NF-κB is followed by its rapid translocation into the nucleus where it activates the transcription of numerous genes including those encoding for cytokines and cell adhesion molecules. Some genes can be transcriptionally up-regulated within minutes after NF-κB activation (2Ghosh S. May M.J. Kopp E.B. Annu. Rev. Immunol. 1998; 16: 225-260Crossref PubMed Scopus (4585) Google Scholar, 4Baldwin Jr., A.S. Annu. Rev. Immunol. 1996; 14: 649-683Crossref PubMed Scopus (5552) Google Scholar). NF-κB transcription factors are dimers belonging to the Rel family (5Sen R. Baltimore D. Cell. 1986; 46: 705-716Abstract Full Text PDF PubMed Scopus (1924) Google Scholar). All five mammalian NF-κB subunits, p65 (RelA), RelB, c-Rel, p50 (and its precursor p105), and p52 (and its precursor p100) contain an N-terminal Rel homology domain responsible for their dimerization, nuclear localization, and DNA binding (6Siebenlist U. Franzoso G. Brown K. Annu. Rev. Cell Biol. 1994; 10: 405-455Crossref PubMed Scopus (2011) Google Scholar, 7Verma I.M. Stevenson J.K. Schwarz E.M. Van Antwerp D. Miyamoto S. Genes Dev. 1995; 9: 2723-2735Crossref PubMed Scopus (1655) Google Scholar). NF-κB subunits can form various dimers, but the classical, best characterized form is composed of p50 and p65 (1Baeuerle P.A. Baltimore D. Cell. 1996; 87: 13-20Abstract Full Text Full Text PDF PubMed Scopus (2919) Google Scholar, 7Verma I.M. Stevenson J.K. Schwarz E.M. Van Antwerp D. Miyamoto S. Genes Dev. 1995; 9: 2723-2735Crossref PubMed Scopus (1655) Google Scholar, 8Thanos D. Maniatis T. Mol. Cell. Biol. 1995; 15: 152-164Crossref PubMed Scopus (127) Google Scholar). p65, RelB, and c-Rel contain a C-terminal transcription activation domain, and they can therefore form transcription-activating dimers with each other and with p50 or p52. p50 and p52 proteins lack the transcription activation domain, and the homodimers they form are mostly suppressors of gene expression (9Zhong H. May M.J. Jimi E. Ghosh S. Mol. Cell. 2002; 9: 625-636Abstract Full Text Full Text PDF PubMed Scopus (809) Google Scholar). NF-κB dimer is held in an inactive state in the cytoplasm by an inhibitor protein (IκB) that masks the NLSs of the subunits (10Beg A.A. Ruben S.M. Scheinman R.I. Haskill S. Rosen C.A. Baldwin Jr., A.S. Genes Dev. 1992; 6: 1899-1913Crossref PubMed Scopus (610) Google Scholar, 11Ganchi P.A. Sun S.C. Greene W.C. Ballard D.W. Mol. Biol. Cell. 1992; 3: 1339-1352Crossref PubMed Scopus (204) Google Scholar, 12Henkel T. Zabel U. van Zee K. Müller J.M. Fanning E. Baeuerle P.A. Cell. 1992; 68: 1121-1133Abstract Full Text PDF PubMed Scopus (304) Google Scholar, 13Zabel U. Henkel T. Baeuerle P.A. J. PubMed Scopus Google Scholar). the nuclear translocation of the p50/p65 molecules in and All molecules contain with the of NF-κB molecules. The C-terminal of and proteins also contain repeats and they can as an (2Ghosh S. May M.J. Kopp E.B. Annu. Rev. Immunol. 1998; 16: 225-260Crossref PubMed Scopus (4585) Google Scholar, 4Baldwin Jr., A.S. Annu. Rev. Immunol. 1996; 14: 649-683Crossref PubMed Scopus (5552) Google Scholar, Cell. 1992; Full Text PDF PubMed Scopus Google Scholar). of NF-κB Rel to DNA or have been Müller J. 16: PubMed Google Scholar, S.C. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T. S. Ghosh G. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, Ghosh G. 1998; PubMed Scopus Google Scholar, G. van G. Ghosh S. 1995; PubMed Scopus Google Scholar, Ghosh G. 2001; 9: Full Text Full Text PDF PubMed Scopus Google Scholar, Ghosh G. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, S. T. Ghosh S. Ghosh G. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). p50/p65 are activated by the that N-terminal I.M. Stevenson J. U. S. PubMed Scopus Google Scholar, Baltimore D. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar, E. PubMed Scopus Google Scholar, H. J. PubMed Scopus Google Scholar, E. G. 1998; PubMed Scopus Google Scholar, S. G. R. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, Annu. Rev. Immunol. PubMed Scopus Google Scholar). of is rapidly by the Annu. Rev. Immunol. PubMed Scopus Google Scholar, T. T. Baeuerle P.A. PubMed Scopus Google Scholar). a the NLSs of p50 and p65 proteins are and the dimers are into the nucleus where they NF-κB p50/p65 and p50 homodimers are the NF-κB in cells. p50 homodimer has been to process are where the C-terminal domain of as an p50 homodimer Cell. 1992; Full Text PDF PubMed Scopus Google Scholar, Annu. Rev. Immunol. PubMed Scopus Google Scholar, Greene W.C. J. PubMed Google Scholar). nonstimulated of proteins are to form p50 homodimers H. S. K. 2001; PubMed Scopus Google Scholar). The p50 and p65 proteins is p50 but the of p50/p65 heterodimer in the cytoplasm is Ghosh G. 1998; PubMed Scopus Google Scholar, Greene W.C. J. PubMed Google Scholar). are by the nuclear into the cytoplasm and the nucleus. The nuclear nuclear pore the the The of molecules in is regulated by nuclear import and export that contain NLSs are imported into the nucleus by importin Importin α binds to NLS and importin is responsible for the of the to the of the followed by translocation of the the D. U. Annu. Rev. Cell Dev. Biol. 15: PubMed Scopus Google Scholar, Mol. Biol. Rev. 2001; PubMed Scopus Google Scholar). NLS of a of and Mol. Cell. Biol. 9: PubMed Scopus Google Scholar, 16: Full Text PDF PubMed Scopus Google Scholar). NLSs are in p50 and p65 J. PubMed Google Scholar, J. 10: PubMed Scopus (127) Google Scholar). have shown that molecules are into the nucleus by and by directly with proteins of the J. Rev. Mol. Cell. Biol. PubMed Scopus Google Scholar). importin α family have been identified in importin importin α3 importin α4 importin importin and importin C.A. J. R. U. S. 1994; PubMed Scopus Google Scholar, Baltimore D. U. S. 1994; PubMed Scopus Google Scholar, S. S. H. E. PubMed Scopus (204) Google Scholar, T. S. T. T. PubMed Scopus Google Scholar, K. U. S. 1998; PubMed Scopus Google Scholar, S. H. D. E. Mol. Cell. Biol. PubMed Google Scholar). The of importin α α and importin have been E. G. J. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T. J. Mol. Biol. PubMed Scopus Google Scholar). Importin α molecules contain a central domain that of armadillo the with the importin α has NLS binding that directly with the NLS of the The repeats the N-terminal NLS binding site and the repeats the C-terminal NLS binding site E. G. J. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T. J. Mol. Biol. PubMed Scopus Google Scholar, K. R. J. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). We that nuclear import of NF-κB p50/p65 is mediated by importin α3 and importin Importin α3 is also in import of p50 Importin α molecules bind to the previously identified NLSs of p50 and p65 proteins. by site-directed mutagenesis show that p50 is by the N-terminal and p65 by the C-terminal NLS binding site of importin α3. analysis Cell and Cell used as by the and α3 have been previously S. H. D. E. Mol. Cell. Biol. PubMed Google Scholar). In and and or and used and and and and cell in in with and the H. K. K. T. J. Google in with as In experiments the in the growth with tumor necrosis cell of by The of and of that used for expression in as previously 1986; Scholar). in vitro and it and DNA and as as the in the repeats and of importin α3 have been previously K. R. J. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). to α3 used site-directed mutagenesis The used p50 and p65 in and by of and NLS to p50 and p65 the and p50 and p65 for and and by to and C-terminal and for into the site of K. J. Biol. Full Text Full Text PDF PubMed Scopus Google and expression The used in and and for p50 and in and for All DNA to a for the expression by the as a an N-terminal with a site the and in and and the site in The with and into the site of the expression 1986; Scholar). importin and p65 by to and C-terminal importin α4 and or importin and for into the site of used in and and for importin and for importin and for importin and for importin and for p50 and and for as previously 1986; Scholar). of in E. and and of Cell and as as in the repeats and importin α3 in E. as proteins for in and with and for and by protein of human importin and p65 in the with p50 or for and and cell by the in for The by a Cell by of cell with or The and in and for The by a Cell by for Importin and proteins to bind to of for in followed by with the of proteins with of cell and for followed by with in of and the proteins PubMed Scopus Google Scholar). The with or followed by with and and of the proteins with the as by the the binding of in vitro proteins in to in vitro p65, or proteins to bind to of for followed by with proteins in of and The and with as by the and of protein with of NF-κB p50 or NF-κB p65 proteins in for followed by with the with of cell with for or for followed by with and with and with p65, importin and IκBα. with of for or The and as by Rosen G. 1996; PubMed Google Scholar). of and NF-κB with as and they in and with for in a to of the with the The with the with the for in binding and proteins in of and and with p50 and p65 proteins. and and or with S. K. K. S. J. Biol. Full Text Full Text PDF PubMed Scopus Google for followed by with in the of for The with for and for as previously K. T. T. K. J. Biol. 1996; Full Text Full Text PDF PubMed Scopus Google Scholar). The for and or p50 as in the and a NF-κB to Importin α3 and Importin activation NF-κB is the cytoplasm into the nucleus. The of NF-κB has been to be mediated importin and the of the nuclear import of NF-κB have the of NF-κB with importin human with expression used for importin isoforms be in E. or by Cell and the cellular proteins to bind to or or or to by for the of p50 and shown in p50 and p65 proteins to importin α3 and to a to importin binding to or of p50 to importin α3 also nonstimulated used in experiments that p50 and p65 to importin α3 and α4 binding to importin or importin α3 used in the binding of cellular to NF-κB proteins used and in Cell and the proteins in the cell to bind to and proteins followed by for the of importin and α3. is shown in importin α3 to and proteins. We importin binding to or We to in vitro with in experiments by with or Cell and the proteins in the cell to bind to or proteins by for the of p65, importin and IκBα. is shown in importin α3 with p50 and p65 only after when the free of IκBα. of p50/p65 p50/p65 in the cytoplasm associated with their IκBα. of including in of and its followed by translocation of the free p50/p65 heterodimer into the nucleus and activation of genes NF-κB binding sites. has been that in nonstimulated are the nucleus and cytoplasm Van Antwerp D. J. PubMed Google Scholar, Miyamoto S. U. S. PubMed Scopus Google Scholar, R. Mol. Cell. Biol. PubMed Scopus Google Scholar, S. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). has been that is mediated by the NLS of p50 that be in the S. T. Ghosh G. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). the of NF-κB binding to importin with for cell and the proteins in the cell by with and The protein of and p65 the rapidly after to after and the protein after The of the form of also a rapid of the of and it after of The form of after of to the of the of NF-κB to bind to importin α3 the proteins in the cell to bind to α3. protein and the proteins by for the of p50 and shown in p65 binding to importin α3 only after the Importin α3 of p50 also nonstimulated and The p50 nonstimulated as in also with but in the protein to importin α3 that the p50 protein to importin α3 nonstimulated is in the form of free p50 p65 binding to importin α isoform nonstimulated and p50 homodimers also to bind DNA nonstimulated experiments NF-κB with for and proteins with NF-κB binding and genes followed by with and p65 dimers to NF-κB only after but of p50 homodimers also nonstimulated are in with the experiments in and binds to the N-terminal and p65 to the C-terminal NLS binding site of importin the human importin α importin α isoforms can be into The the in the of the importin α used in the The are as importin α3 α4 and an of human and that are in NLS binding are shown in of the and in each are shown by of importin α domain The with NLSs are shown in In the the p65 homodimer domain is shown in a with and The p65 NLSs are shown in DNA is shown as a The the are and or with of for Cell and the proteins in the cell to bind to or or of α3 for The binding experiments as in the for with and as also with to the of α3. in vitro p65 and p50 or p50 p65 to bind to or or of α3. proteins in and of p50 and p65 proteins is In vitro used as is shown to the of the of p65 and p50/p65 but p50 to Importin NF-κB binding to α3 and used in vitro p50 and p65 proteins in binding In vitro p50 homodimers are p65 homodimers p50/p65 dimers are when encoding p50 and p65 are Greene W.C. J. PubMed Google Scholar). to that in vitro proteins in a to NF-κB proteins in importin α binding experiments We that also in vitro p50 homodimers to importin α3 and to a to importin p65 homodimers to importin α3 but binding to importin it has previously been shown that is also in the to study the importin import and binds to is in binding to the that is into the nucleus by the importin import of be mediated with of the S. S. Mol. Cell. Biol. PubMed Scopus Google or it is into the nucleus by a with proteins J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). it is that nuclear translocation of NF-κB, to the binding of NF-κB in importin α3 binding binds to p50/p65 and with to p65 homodimers and with to p50 homodimers T. Ghosh G. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). shown in the binding of p65 homodimers but p50 homodimers to importin α3. also the binding of p50/p65 to importin α3 in in a with the NF-κB dimers that to α3 with the in and that the NF-κB that are to importin α3 and are into the nucleus are free of IκBα. NLSs of p50 and p65 with α3 and and p65 proteins have been shown to contain NLSs J. PubMed Google Scholar, J. 10: PubMed Scopus (127) Google Scholar). study are in binding of p50 and p65 proteins to α3 and binding experiments with E. and in vitro p50 and p65 proteins. In vitro or NLS p50 and p65 to bind to α3 or followed by of importin p50 and p65 by and p50 and p65 proteins to α3 and p50 and p65 to bind to importin α isoform and the also in the nuclear import of the and p50 and p65 in by in p50 and p65 into the nucleus proteins show that the NLSs of p50 and p65 the binding of NF-κB to α3 and and its nuclear p65 is known to a nuclear export signal mediates its to the inhibitor for used in to the nuclear export of p50 to the and p65 to the C-terminal NLS of Importin are molecules that contain the with proteins. N-terminal repeats have been as the NLS binding site and C-terminal repeats have been to as the NLS binding site E. G. J. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T. J. Mol. Biol. PubMed Scopus Google of the repeats the and C-terminal NLS binding that the and are in repeats The of the is the repeats the repeats are in and when human are with each other and the of NF-κB binding to importin α3 in the N-terminal and C-terminal NLS binding of importin α3. in TNF-α-stimulated or nonstimulated cell to bind to or or importin α3 molecules followed by analysis of p50 and p65 by in the p65 in the repeats to an of p65 binding in the of p65, in importin α3 p50 binding in the repeats the by cellular TNF-α-stimulated NF-κB used in vitro p50 and p65 proteins and the in α3 binding In also an importin α3 is in vitro p50 and p65 with the TNF-α-stimulated cellular p50 and p65 proteins. in importin α3 the binding of and in repeats the binding of in repeats in importin α3 the binding of proteins. show that the N-terminal repeats of importin α3 form the binding site for p50 p65 is to the C-terminal NLS binding NLS p65 the of p50 has been that p50 and p65 proteins have their NLSs J. PubMed Google Scholar, J. 10: PubMed Scopus (127) Google Scholar). have shown that NLSs p50 and p65 with importin α3 (and importin and their nuclear import and the of and p65 protein cellular of used to the nuclear export of with or p65 the of the cellular p50 the p50 nuclear and a expression in TNF-α-stimulated and in p65 and after it with p50 in the cell nucleus p65 also after that a of p50 homodimers is into the nucleus of p65 and p65 as a for nuclear import of p50 Importin α3 and Importin α4 of the NF-κB of NF-κB transcription factors the cytoplasm into the nucleus is a in their signal contain NLS and they are imported into the nucleus the importin In the present study show that NF-κB p50/p65 are into the nucleus by importin α3 and importin Importin α3 also to be in the nuclear import of p50 homodimers in cells. is shown that the previously identified NLSs of p50 and p65 molecules are the for importin α In study also importin to NF-κB after to a importin α3. binding mediated by the NLSs of p50 and p65 proteins. binding of importin the binding of cellular importin to or proteins. the of it be importin is and in NF-κB nuclear importin α isoforms are in the and but they have is that the NLS binding of importin α to the of protein only the directly with the of the NLS to the importin α binding and NLS binds to importin isoforms C.A. J. R. U. S. 1994; PubMed Scopus Google Scholar, Baltimore D. U. S. 1994; PubMed Scopus Google Scholar, S. S. H. E. PubMed Scopus (204) Google Scholar, T. S. T. T. PubMed Scopus Google Scholar, K. U. S. 1998; PubMed Scopus Google Scholar, S. H. D. E. Mol. Cell. Biol. PubMed Google the binds to importin α3 and to a to importin K. R. J. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). Importin α molecules have NLS binding that directly with the NLS of the repeats the N-terminal NLS binding site and repeats the C-terminal NLS binding We have previously shown that importin α3 is to its or C-terminal binding for binding proteins. is to the C-terminal NLS binding site is to the N-terminal NLS binding site K. R. J. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). present study demonstrates in NF-κB p50 and p65 molecules are by NLS binding of importin p50 is by the N-terminal and p65 by the C-terminal NLS binding is an that p50 and p65 NLSs be to the NLS binding of the importin α of binding the nuclear the p50 homodimers are to importin α p50 NLS to be only by the N-terminal binding Importin α3 and α4 to the importin and a of homology S. H. D. E. Mol. Cell. Biol. PubMed Google and We that importin α4 can in the in NF-κB as importin α3. is that also have S. H. D. E. Mol. Cell. Biol. PubMed Google Scholar, T. E. Mol. Cell. Biol. PubMed Scopus Google Scholar). NF-κB, signal transducers and activators of transcription are transcription factors activated by activation are and into the nucleus by the importin In study that and contain NLSs that only in The NLSs of of a dimer have to be for nuclear import to K. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). homodimers and bind to the C-terminal NLS binding site of importin and importin α molecules are to the dimer into the nucleus K. R. J. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, R. K. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). In to it that in NF-κB dimers each NLS J. PubMed Google Scholar). it has also been that of a Rel homodimer an NLS for nuclear import R. Genes Dev. PubMed Scopus Google Scholar). NF-κB the and p65 an NLS and a NES, free p50/p65 and p65 homodimers are into and of the nucleus. In the of leptomycin an inhibitor of nuclear p65 dimers in the nucleus Miyamoto S. U. S. PubMed Scopus Google Scholar, R. Mol. Cell. Biol. PubMed Scopus Google Scholar, S. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). its NLS that is when the protein is to NF-κB dimers S.C. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, T. S. Ghosh G. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, S. Mol. Cell. Biol. 1998; PubMed Google Scholar). is to NF-κB dimers it can the cytoplasm and the nucleus by of its NLS and has been by several that in the cytoplasm and the nucleus Van Antwerp D. J. PubMed Google Scholar, Miyamoto S. U. S. PubMed Scopus Google Scholar, R. Mol. Cell. Biol. PubMed Scopus Google Scholar, S. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, S. T. Ghosh G. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). to importin α3 bind to NF-κB dimers when they are associated with IκBα. suggest that NF-κB and are into the nucleus as a the that in of the is followed by nuclear import of the subunits the as a J. Biol. Full Text Full Text PDF PubMed Scopus (127) Google Scholar, E. R. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). of NF-κB and in the the is to the is mediated by Van Antwerp D. J. PubMed Google Scholar, Miyamoto S. U. S. PubMed Scopus Google or by the of p65 Sun S.C. Mol. Cell. Biol. PubMed Scopus Google Scholar). We that of p50 can with importin α3 form of p50 free of of In is p50 Cell. 1992; Full Text PDF PubMed Scopus Google Scholar, H. S. K. 2001; PubMed Scopus Google Scholar, S. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, Ghosh G. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). We that the binding of p50 to importin α3 is of the of the p50 homodimers that are free to bind to importin α3. also and H. S. K. 2001; PubMed Scopus Google Scholar). In to binding of p65 to importin α3 in cells. The of p50/p65 is but with p65, and is also to to p50/p65 binding of p50/p65 to importin is that when is the dimer the p50/p65 heterodimer rapidly binds the of p50/p65 only after is J. Biol. Full Text Full Text PDF PubMed Scopus (127) Google Scholar, E. R. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). of the the of NF-κB and in the nucleus the of for that the is a and in p50/p65 p50 homodimers are regulated by other the of associated with p50 the cell the of p50 homodimers of NF-κB into the nucleus is in The of the has been to be mediated by the free NLS of p50 S. T. Ghosh G. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). and the cytoplasm and nucleus. has been that the of factors that their NLSs Ghosh G. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). it is that when is to NF-κB, importin molecules to with the free to that NF-κB binds to importin α3 and importin α4 and is into the nucleus only when it is free of molecules. In the analysis of NF-κB to importin molecules is to the of molecules. We for the and and for the human p50 and p65 We also for and and for with the cells.

The prevalence of kidney disease is increasing rapidly worldwide, reflecting rising rates of obesity, diabetes, and associated metabolic syndrome (MetS). Chronic kidney disease and related comorbidities such as obesity, diabetes, and hypertension place a significant financial burden on healthcare systems. Despite the widespread use of RAAS inhibitors, intensive blood pressure and glycemic control, and newer therapeutic options consisting of sodium/glucose cotransporter-2 (SGLT-2) inhibitors or glucagon-like peptide-1 (GLP-1) receptor agonists, a significant risk of progression to end-stage renal disease remains in the high-risk obese and diabetic population. The MetS is a cluster of cardiovascular risk factors that adversely affect the development and progression of chronic kidney failure. According to the criteria of the World Health Organization, it is defined by visceral adiposity, impaired glucose tolerance or insulin resistance, atherogenic dyslipidemia, raised blood pressure, and microalbuminuria with a albumin-to-creatinine ratio ≥30 mg/g. At molecular level MetS is marked by a proinflammatory state and increased oxidative stress leading to various pathophysiological changes causing endothelial dysfunction and a hypercoagulable state. Because the kidney is a highly vascularized organ, it is especially susceptible for those microvascular changes. Therefore, the MetS and its individual components are associated with the premature development, acceleration, and progression of chronic kidney disease. Therefore, it is becoming increasingly important to elucidate the underlying mechanisms of MetS-associated chronic kidney disease in order to develop new strategies for preventing and slowing the progression of renal disease. In this review, we will elucidate (i) the renal structural, hemodynamic, and metabolic changes that occur in obesity and obesity-related kidney injury; (ii) the clinicopathological characteristics of obesity-related kidney injury, primarily focusing on obesity-associated glomerulopathy; (iii) the potential additional factors or predisposing factors that may turn patients more susceptible to renal structural or functional compensatory failure and subsequent injury.

The regulation of the ACTH-receptor gene is unique in that it is up-regulated by its own ligand, ACTH. Ligand-induced up-regulation of ACTH-receptor expression may be an important adaptive process directed towards optimizing adrenal responsiveness to ACTH in the context of physiological stress and the maintenance of metabolic homeostasis in which the adrenals play a pivotal role. Whereas enhancement by ligand-induced up-regulation permits a more efficient and rapid glucocorticoid response, negative feedback regulation of glucocorticoids in the hypothalamus and pituitary inhibits ACTH secretion and allows a balanced adrenal response to stress. Since the cloning of the promoter region of the ACTH receptor, considerable progress in the understanding of the regulatory processes has been made. The effects of ACTH on ACTH-receptor expression is dependent on cAMP, probably mediated through AP-1.The profound effect of three SF-1-binding sites in the ACTH-receptor promoter was demonstrated by deletion experiments. Conversely, ACTH-receptor expression can be suppressed by adrenal-specific transcription factors,like DAX-1.Despite an extensive search, no activating ACTH-receptor mutations have been found in adrenal tumors,excluding the ACTH receptor as a relevant oncogene in adrenal tumorigenesis. However, the ACTH receptor may act as a differentiation factor as suggested by LOH in adrenal carcinomas with an undifferentiated tumor type.In benign adrenal tumors, a strong correlation between ACTH-receptor expression and expression of P450 steroidogenic enzymes is evident. This close regulative relationship is lost in adrenal carcinoma, probably as a result of tumor dedifferentiation. Down-regulation of ACTH-receptor expression in normal and neoplastic tissue can be achieved by adrenostatic compounds such as aminoglutethimide and metyrapone.

BACKGROUND: Acute displacement of opioids from their receptors by administration of large doses of opioid antagonists during general anesthesia is a new approach for detoxification of patients addicted to opioids. The authors tested the hypothesis that mu-opioid receptor blockade by naloxone induces cardiovascular stimulation mediated by the sympathoadrenal system. METHODS: Heart rate, cardiac index, and intravascular pressures were measured in 10 patients addicted to opioids (drug history; mean +/- SD, 71 +/- 51 months) during a program of methadone substitution (96 +/- 57 mg/day). Cardiovascular variables and concentrations of catecholamine in plasma were measured in the awake state, during methohexital-induced anesthesia (dose, 74 +/- 44 microg x kg(-1) x min(-1)) before administration of naloxone, and repeatedly during the first 3 h of mu-opioid receptor blockade. Naloxone was administered initially in an intravenous dose of 0.4 mg, followed by incremental bolus doses (0.8, 1.6, 3.2, and 6.4 mg) at 15-min intervals until a total dose of 12.4 mg had been administered within 60 min; administration was then continued by infusion (0.8 mg/h). RESULTS: Concentration of epinephrine in plasma increased 30-fold (15 +/- 9 to 458 +/- 304 pg/ml), whereas concentration of norepinephrine in plasma only increased to a minor extent (76 +/- 44 to 226 +/- 58 pg/ml, P < 0.05). Cardiac index increased by 74% (2.7 +/- 0.41 to 4.7 +/- 1.7 min(-1) x m(-2)), because of increases in heart rate (89 +/- 16 to 108 +/- 17 beats/min) and stroke volume (+44%), reaching maximum 45 min after the initial injection of naloxone. In parallel, systemic vascular resistance index decreased (-40%). Systolic arterial pressure significantly increased (113 +/- 16 to 138 +/- 16 mmHg), whereas diastolic arterial pressure did not change. CONCLUSIONS: Despite barbiturate-induced anesthesia, acute mu-opioid receptor blockade in patients addicted to opioids induces profound epinephrine release and cardiovascular stimulation. These data suggest that long-term opioid receptor stimulation changes sympathoadrenal and cardiovascular function, which is acutely unmasked by mu-opioid receptor blockade. Because of the attendant cardiovascular stimulation, acute detoxification using naloxone should be performed by trained anesthesiologists or intensivists.

The “classical” nuclear protein import pathway depends on importin α and importin β. Importin α binds nuclear localization signal (NLS)-bearing proteins and functions as an adapter to access the importin β-dependent import pathway. In humans, only one importin β is known to interact with importin α, while six α importins have been described. Various experimental approaches provided evidence that several substrates are transported specifically by particular α importins. Whether the NLS is sufficient to mediate importin α specificity is unclear. To address this question, we exchanged the NLSs of two well-characterized import substrates, the seven-bladed propeller protein RCC1, preferentially transported into the nucleus by importin α3, and the less specifically imported substrate nucleoplasmin. In vitro binding studies and nuclear import assays revealed that both NLS and protein context contribute to the specificity of importin α binding and transport.

The Notch signaling pathway is an important regulation system for the development and self-renewal of different tissues. A specific feature of this signaling cascade is the function of Notch as a surface receptor and regulator of gene expression. Hence, Notch activation and signal transduction requires the proteolytic release of the Notch intracellular domain (NICD), which activates the transcription of cell-specific genes after its transport into the nucleus. To date, little is known about the mechanisms that mediate NICD nuclear import. We here show that transport of NICD into the nucleus is mediated by the canonical importin alpha/beta1 pathway. GST pull-down experiments revealed that NICD binds via one of its four potential nuclear localization signals to importins alpha3, alpha4, and alpha7, but not to alpha1 and alpha5. siRNA-mediated knockdown experiments showed that importins alpha3, alpha4 (and to a lesser extent, alpha7) mediate nuclear import of NICD and thus are directly involved in Notch signaling.

BACKGROUND: Cardiovascular stimulation and increased catecholamine plasma concentrations during ketamine anesthesia have been attributed to increased central sympathetic activity as well as catecholamine reuptake inhibition in various experimental models. However, direct recordings of efferent sympathetic nerve activity have not been performed in humans. The authors tested the hypothesis that racemic ketamine increases efferent muscle sympathetic activity (MSA) and maintains the muscle sympathetic response to hypotensive challenges. METHODS: Muscle sympathetic activity was recorded by microneurography in the peroneal nerve of six healthy subjects before and during anesthesia with racemic ketamine (2 mg/kg intravenously plus 30 microg x kg(-1) x min(-1)). Catecholamine plasma concentrations, heart rate, and blood pressure were also determined. Muscle sympathetic neural responses to a hypotensive challenge were assessed by injection of sodium nitroprusside (2-10 microg/kg) before and during ketamine anesthesia. In the final step, increased arterial pressure observed during ketamine anesthesia was adjusted to preanesthetic baseline by sodium nitroprusside infusion (1-6 microg x kg(-1) x min(-1)). RESULTS: Ketamine significantly decreased MSA burst frequency (mean +/- SD, 18 +/- 9 bursts/min to 9 +/- 8 bursts/min) and burst incidence (26 +/- 11 bursts/100 heart beats to 9 +/- 6 bursts/100 heart beats). However, when increased mean arterial pressure (85 +/- 8 mmHg to 121 +/- 20 mmHg) was normalized to the awake baseline by sodium nitroprusside, MSA recovered (25 +/- 18 bursts/min; 23 +/- 14 bursts/100 heart beats). During ketamine anesthesia, both epinephrine (15 +/- 10 pg/ml to 256 +/- 193 pg/ml) and norepinephrine (250 +/- 105 pg/ml to 570 +/- 270 pg/ml) plasma concentrations significantly increased, as did heart rate (67 +/- 13 beats/min to 113 +/- 15 beats/min). Hypotensive challenges similarly increased MSA both in the awake state and during ketamine anesthesia. CONCLUSIONS: During increased arterial blood pressure associated with ketamine, sympathetic discharge to muscle blood vessels decreases at the same time that plasma concentrations of norepinephrine increase. When this increase in arterial blood pressure is reversed, MSA during ketamine is not changed from preketamine baseline recordings. Finally, hypotensive challenges still evoke an unchanged sympathetic reflex response. Thus, our results do not support the assumption that ketamine anesthesia increases sympathetic nerve activity in a generalized fashion.

Ziel der Studie war die differenzierte Erfassung der Lebensqualität von zwei Patientengruppen mit terminaler Niereninsuffizienz in Abhängigkeit vom Nierenersatzverfahren (Dialyse vs. Transplantation) im Vergleich zu einer Gruppe gesunder Vergleichspersonen. In die Studie wurden 149 erfolgreich nierentransplantierte Patienten und 149 Dialysepatienten auf der Warteliste für die Transplantation am Transplantationszentrum Essen eingeschlossen. Als Vergleichsgruppe wurden weiterhin 149 gesunde Personen, die im Schneeballsystem ausgehend von Angehörigen des Universitätsklinikums Essen gewonnen wurden, eingeschlossen. Die jeweils 149 Personen der drei Gruppen wurden streng nach Alter und Geschlecht parallelisiert. Die aktuellen medizinischen Daten wurden den Patientenakten entnommen, die Lebensqualität durch ein globales Instrument, die Münchner Lebensqualität-Dimensionen-Liste (MLDL), und zwei spezifische Verfahren, das Brief Symptom Inventory (BSI) und die Kurzform des Fragebogens zur sozialen Unterstützung (K-22), erfasst. Die transplantierten Patienten und die gesunden Vergleichspersonen berichteten über eine höhere Lebensqualität als die Dialysepatienten (p < 0,0001). Dies betraf insbesondere die Bereiche „Physis” und „Psyche” und den Bereich „Alltagsleben”, nicht aber das „Sozialleben”. Beide Patientengruppen beschrieben ein vergleichbares Maß an sozialer Unterstützung, das geringer war als bei den Gesunden (p < 0,006). Die Zufriedenheit mit der sozialen Unterstützung wiederum war bei beiden Patientengruppen höher als bei den gesunden Vergleichspersonen (p < 0,0001). Die Nierentransplantation führte im Vergleich zu Dialysepatienten auf der Warteliste zu höherer Lebensqualität in körperlichen, psychischen und funktionalen Bereichen und glich sie darüber hinaus derjenigen Gesunder an. Die niedrige soziale Unterstützung der terminal niereninsuffizienten Patienten verlangt größere Aufmerksamkeit. Internationale multizentrische Längsschnittstudien sollten die Lebensqualität terminal niereninsuffizienter Patienten unter Berücksichtigung der unterschiedlichen Therapieformen untersuchen.

Importin α is involved in the nuclear import of proteins. It also contributes to spindle assembly and nuclear membrane formation, however, the underlying mechanisms are poorly understood. Here, we studied the function of importin α7 by gene targeting in mice and show that it is essential for early embryonic development. Embryos lacking importin α7 display a reduced ability for the first cleavage and arrest completely at the two-cell stage. We show that the zygotic genome activation is severely disturbed in these embryos. Our findings indicate that importin α7 is a new member of the small group of maternal effect genes.

BACKGROUND: Acquired thrombotic thrombocytopenic Purpura (aTTP) is a life-threatening ultra-orphan disease with a reported annual incidence between 1.5 and 6.0 cases per million in Europe and mainly affecting otherwise young and healthy adults aged 40 years on average. The goal of this study was to assess the incidence of aTTP in Germany. METHODS: A systematic review was performed to determine the published evidence on the aTTP epidemiology in Germany. To obtain additional evidence on the proportion of aTTP cases within the national Thrombotic Microangiopathy (TMA) population a hospital-level study was performed, using a retrospective data collection approach. Diagnosis of aTTP was confirmed if ADAMTS13 level were < 10% and/or the medical records explicitly mentioned aTTP diagnosis. The aggregated hospital data were then projected to the national level using logistic regression techniques. RESULTS: The systematic literature search did not provide incidence estimates of aTTP in Germany. Eight centers (≈27% of the top 30 TMA hospitals) delivered data according to a predefined data collection form. On average (year 2014-2016) a total number of 172 aTTP episodes per year was projected (95% confidence interval [95%CI]: 132-212). The majority were newly diagnosed aTTP cases (n = 121; 95%CI: 105-129), and 51 were recurrent aTTP cases (95%CI: 27-84). The average annual projected incidence (year 2014-2016) of aTTP episodes was 2.10 per million inhabitants in Germany (95%CI: 1.60-2.58). CONCLUSIONS: The determined annual incidence of newly diagnosed aTTP cases and the overall annual incidence of aTTP episodes in Germany confirm the ultra-orphan character of aTTP. An external validation against international registries (France, UK and USA) shows that our findings are quite comparable with those international incidence rates.

The human heart contains both beta 1-adrenoceptors and a considerable number of beta 2-adrenoceptors, both of which bring about positive inotropic and chronotropic effects of beta-adrenoceptor agonists in vitro and in vivo. In chronic heart failure, the decrease in beta-adrenoceptor function is related to the severity of the disease. However, both cardiac beta 1- and beta 2-adrenoceptors seem to be differentially affected depending on the type of heart failure and its aetiology. beta 1-adrenoceptor function decreases in all forms of chronic heart failure. beta 2-adrenoceptor function, on the other hand, decreases in mitral valve disease, tetralogy of Fallot and end-stage ischaemic cardiomyopathy, and seems to be unaltered (or only mildly uncoupled) in end-stage dilated cardiomyopathy, and possibly in aortic valve disease. Since the human heart has few spare beta-adrenoceptors and these decline with increasing degree of heart failure, beta-adrenoceptor agonists (but only non-selective full agonists) may be of therapeutic use only if the heart needs acute inotropic support; in long-term treatment they may be not effective, since tolerance develops. On the other hand, for long-term treatment selective beta 1-adrenoceptor antagonists may be beneficial since they protect the heart from the deleterious effects of chronic exposure to high (cardiac derived) noradrenaline and simultaneously may restore the previously reduced beta-adrenoceptor function.

Type 2 diabetes mellitus (T2DM) is associated with a high risk of complications, essentially macrovascular events. Surprisingly, the effect of improved glucose control on coronary and cerebrovascular complications and the target level of glycated hemoglobin (HbA(1c)) in this population remains questionable. We here report the results of 4 recently published randomized controlled trials (ACCORD, ADVANCE, VADT, UKPDS post-trial), which did not demonstrate a significant reduction of cardiovascular events in the intensive group compared to the standard group. On the contrary, in ACCORD, the study with the most ambitious goal (HbA(1c) < 6%), the overall and cardiovascular mortality was greater in the intensive group, although the risk of microangiopathic complications, especially nephropathy, was significantly decreased. VADT suggests that one possibility for the lack of observed effect of intensive therapy could be that the cardiovascular benefit is delayed. This contrasts strongly with the long-term postintervention outcomes of UKPDS, which show a persistent benefit of glycemic control during 10 years of post-trial follow-up ('legacy effect'). Therefore, the best way to protect patients with T2DM against coronary and cerebrovascular disease is to target all cardiovascular risk factors as early as possible by an individualized approach.

BACKGROUND: The effects of gestational nucleoside reverse transcriptase inhibitors (NRTIs) on mitochondrial DNA (mtDNA) are controversial. The effects of mtDNA depletion on mitochondrial function have not been assessed. METHOD: In peripheral blood mononuclear cells (PBMCs) from infants born to HIV-infected women and infants born to HIV-1-uninfected women, mtDNA copy numbers were determined by quantitative PCR; nuclear (COXIV)- and mitochondrial (COXII)-encoded polypeptides of the oxidative phosphorylation enzyme cytochrome c-oxidase (COX or complex IV) were quantified by Western blot. RESULTS: Overall, 86 infants born to HIV-infected women and 50 controls were studied. HIV-infected mothers had a median CD4 count of 506 cells/microL; 59% had HIV RNA 50 copies/mL. No infant had clinical evidence of mitochondrial disease. The birth weight was lower (p = .016) and the body length higher (p = .002) in the HIV-exposed newborns. Eighty-one HIV-infected women had received gestational NRTIs (median duration 162 days). Median mtDNA copies/PBMC in the HIV-exposed infants were 505 (range, 120-1365) vs. 213 (27-426) in controls (p < .001). COX II/IV ratios were similar in both groups. Although mtDNA levels correlated inversely with maternal lactate, mitochondrial indices did not correlate with maternal CD4+ count, HIV RNA, smoking, or alcohol consumption. CONCLUSION: We found elevated mtDNA copy numbers in PBMC of infants born to HIV-infected women, the majority of whom received NRTI-based therapy, when compared to those born to healthy HIV-negative controls, but there was no difference in mtDNA-encoded respiratory chain protein. The clinical consequence of these findings is unknown and requires further investigations.

OBJECTIVE: We examined the effects of fluvastatin treatment on the development of kidney injury in experimental deoxycorticosterone-acetate (DOCA)-salt hypertension. METHODS: Male Sprague-Dawley rats underwent unilateral nephrectomy and received subcutaneous DOCA pellets as well as 1% NaCl for drinking. Simultaneously, rats were treated with 5 mg/kg per day fluvastatin, or solvent only for 6 weeks. Mean arterial pressure was measured intraarterially. Glomerulosclerosis, interstitial fibrosis, cell proliferation, inflammation and podocyte damage were evaluated on kidney sections. Inflammatory markers were measured by real-time PCR. RESULTS: Mean arterial pressure was elevated in DOCA-salt-treated rats but unaltered by fluvastatin. Serum cholesterol was markedly elevated in DOCA-salt-treated rats and tended to be lower in fluvastatin-treated animals. Fluvastatin treatment decreased the mortality of DOCA-salt-treated rats. Urinary protein excretion, glomerular proliferation and macrophage infiltration as well as glomerulosclerosis were reduced by fluvastatin. Fluvastatin alleviated podocyte damage and glomerular osteopontin protein expression, which was localized in podocytes. On the contrary, interstitial fibrosis, inflammation and interstitial cell proliferation of DOCA-salt-treated rat kidneys were not influenced by fluvastatin. CONCLUSION: Statin treatment reduces mortality and glomerular damage independent from blood pressure in a low-renin model of hypertensive nephrosclerosis. A reduction of podocyte damage and macrophage infiltration may explain the beneficial effects of fluvastatin.

It was found that in Belgium, renal imaging techniques, demonstrating a decreased renal mass of both kidneys combined with either bumpy contours or papillary calcifications, were the only methods to reliably diagnose analgesic nephropathy (AN) in patients with end-stage renal failure. However, these criteria were selected in an area with a high prevalence of this disease (15.6% of the dialysis population at December 1990). To evaluate the criteria selected to diagnose AN in populations with lower or unknown prevalences of AN, the Analgesic Nephropathy Network of Europe (ANNE) was formed, consisting of 23 dialysis units from 14 European countries and Brazil. During 1991-1992, 598 new patients with equivocal diagnosis of renal disease (excluding biopsy-proven glomerulonephritis, polycystic disease, diabetic nephropathy and other systemic diseases) and who began renal replacement therapy in the ANNE centres were evaluated by a short questionnaire and two renal imaging techniques: sonography and either tomography or computed tomography (CT) scan. A comparison of 82 abusers (daily use of analgesic mixtures for at least 5 years) and 495 controls corroborated the excellent diagnostic performance of the renal imaging techniques for AN. We recommend the use of these renal imaging criteria in all patients without a clear renal diagnosis in order to obtain a more reliable insight into the magnitude of the AN problem in different countries.

The reflex threshold of the stapedius muscle is normally 10-20 dB lower than the limit of discomfort. Both depend upon the intensity of the internal ear stimulation. On this are based the monaural objective recruitment test by impedance measurement as well as the subjective loudness tolerance test. After prolonged sound exposure, however, both supraliminal thresholds behave differently: In persons regularly exposed to industrial noise the limit of discomfort is generally found to be shifted to considerably higher sound levels, while the reflex threshold remains normal or is only slightly raised, even in the frequency range of larger hearing losses. Experimental sound exposure in normal-hearing persons unaccustomed to industrial noise suggest the same. Hence, we have to conclude that the higher sound tolerance of workers accustomed to noise is due only to a process of central adaptation, and not to habituation of the internal ear, as has been repeatedly postulated in the present literature on industrial medicine. The peripheral receptors remain sensitive to strong exposure, even though the latter has lost its subjective discomfort long ago—which is elicited primarily in the cochlea. The span between the objective threshold of stapedius reflex and the subjective limit of discomfort can be regarded almost as an indicator of the inurement to noise.Le seuil du réflexe cochléo-stapédien est normalement 10-20 dB plus bas que le seuil d'inconfort. Les deux dépendent de l'intensité de la stimulation de l'oreille interne. L'épreuve du recrutement objectif monaural par l'audiométrie de l'étude de l'impédance acoustique, ainsi que l'épreuve subjective de tolérance à l'intensité du son, sont toutes deux basées sur cela. Après une exposition au son prolongée, les deux seuils se comportent différemment: parmi les personnes exposées regulièrement aux bruits industriels, par exemple, le seuil d'inconfort est généralement changé à un niveau de sons considérablement plus élevés, le seuil des variations de l'impédance acoustique reste normal ou est sensiblement élevé, měme dans la zone de fréquence de plus grandes pertes d'audition. Les résultats, obtenus de personnes à ouïe normale, exposées à de bruits industriels auxquels elles n'étaient pas accoutumées, suggèrent la měme chose. Nous devons done conclure que la plus grande tolérance aux sons intenses des travailleurs exposés fréquemment aux bruits industriels ne peut ětre expliquée que par un procédé d'adaptation centrale, et non par l'accoutumance de l'oreille comme fréquemment postulé dans la littérature médicale industrielle. Les récepteurs périphériques restent sensibles à l'exposition aux bruits élevés, měme s'ils ont perdu depuis longtemps leur inconfort subjectif, lequel est provoqué premièrement dans la cochlée. La différence entre le seuil du réflexe cochleó-stapédien et le seuil d'inconfort subjectif peut ětre considérée comme une indication d'accoutumance au bruit.

Hepatitis C infection is a common problem in dialysis units. The prevalence ranges from 3% to more than 50%. Several reports have described a variable reduction of HCV-RNA during hemodialysis treatment sessions. But so far nothing is known about the HCV antigenemia or the kinetics of the reduction of HCV-RNA and HCV antigenemia during these sessions. HCV-RNA was monitored using the VERSANT HCV bDNA assay 3.0 (Bayer Healthcare Diagnostics, Leverkusen, Germany) or the HCV-Monitor TaqMan (Roche Diagnostics). HCV antigenemia was tested by using Ortho-trac-C assay (Ortho Clinical Diagnostics, Neckargemünd, Germany). Kinetics of HCV-RNA were available in 15 dialysis sessions measured by bDNA assay and in 5 dialysis sessions measured by rt-PCR. Quantitative HCV-antigenemia was available in fourteen dialysis sessions. Not only HCV-RNA but as expected also the HCV-antigenemia fell during the dialysis session. However, while the average reduction of HCV-antigen appears steady and linear, the level of HCV-RNA seems to be stable during the first 3 hr of dialysis, and decreases rapidly during the last 2 hr. The results seem to be independent of the HCV-RNA detection method. The different kinetics of HCV RNA and HCV antigen load suggest that there are different mechanisms responsible for the reduction of the HCV antigen and HCV-RNA, respectively. Reduction of viral load during dialysis session indicates a potential benefit of dialysis in case of HCV associated antiviral therapy.

This study compared the immunogenicity and safety of a booster dose of HepB-CpG (HEPLISAV-B® vaccine) with HepB-Eng (Engerix-B®) and HepB-AS04 (Fendrix®) in patients receiving chronic hemodialysis. This was a multicenter, randomized, open-label, phase 3 study of adults receiving hemodialysis with antibodies to HBsAg (anti-HBs) <10 mIU/mL at study entry. The objective was to compare the seroprotection rate (SPR) induced by HepB-CpG with HepB-Eng or HepB-AS04. The SPR was defined as the percentage of patients with anti-HBs ≥10 mIU/mL post-vaccination. At 20 sites in Germany, 155 participants were randomized: HepB-CpG = 54; HepB-Eng = 50; and HepB-AS04 = 51. Of the 149 participants in the modified intention-to-treat population, 76.5% had not previously responded to at least one series of hepatitis B vaccine. Based on a post hoc analysis, the SPR in HepB-CpG recipients (52.8%; 95% confidence interval [CI]: 38.6%, 66.7%) was significantly higher than in HepB-Eng recipients (32.6%; 95% CI: 19.5%, 48.0%), and non-inferior to that in HepB-AS04 recipients (43.1%; 95% CI: 29.3%, 57.8%). Local post-injection reactions occurred in significantly fewer HepB-CpG (9.3%) than HepB-AS04 recipients (31.4%; p = .007) and at a similar rate to HepB-Eng recipients (8.2%). Systemic post-injection reactions in HepB-CpG recipients (18.5%) were similar to the HepB-AS04 group (19.6%) and higher than in the HepB-Eng group (12.2%). In this difficult-to-immunize population, a booster dose of HepB-CpG induced significantly higher levels of seroprotection than HepB-Eng with a similar safety profile. The higher levels of immunogenicity were not accompanied by higher levels of local post-injection reactions compared with HepB-AS04.

BACKGROUND: Mu-opioid receptor blockade by naloxone administered for acute detoxification in patients addicted to opioids markedly increases catecholamine plasma concentrations, muscle sympathetic activity (MSA), and is associated with cardiovascular stimulation despite general anesthesia. The current authors tested the hypothesis that the alpha2-adrenoceptor agonist clonidine (1) attenuates increased MSA during mu-opioid receptor blockade for detoxification, and (2) prevents cardiovascular activation when given before detoxification. METHODS: Fourteen mono-opioid addicted patients received naloxone during propofol anesthesia. Clonidine (10 microg x kg(-1) administered over 5 min + 5 microg x kg(-1) x h(-1) intravenous) was infused either before (n = 6) or after (n = 6) naloxone administration. Two patients without immediate clonidine administration occurring after naloxone administration served as time controls. Muscle sympathetic activity (n = 8) in the peroneal nerve, catecholamine plasma concentrations (n = 14), arterial blood pressure, and heart rate were assessed in awake patients, during propofol anesthesia before and after mu-opioid receptor blockade, and after clonidine administration. RESULTS: Mu-receptor blockade markedly increased MSA from a low activity (burst frequency: from 2 burst/min +/- 1 to 24 +/- 8, means +/- SD). Similarly, norepinephrine (41 pg/ml +/- 37 to 321 +/- 134) and epinephrine plasma concentration (13 pg/ml +/- 6 to 627 +/- 146) significantly increased, and were associated with, increased arterial blood pressure and heart rate. Clonidine immediately abolished both increased MSA (P < 0.001) and catecholamine plasma concentrations (P < 0.001). When clonidine was given before mu-opioid receptor blockade, catecholamine plasma concentrations and hemodynamic variables did not change. CONCLUSIONS: Administration of the alpha2-adrenoceptor agonist clonidine decreases both increased MSA and catecholamine plasma concentrations observed after mu-opioid receptor blockade for detoxification. Furthermore, clonidine pretreatment prevents the increase in catecholamine plasma concentration that otherwise occurs during mu-opioid receptor blockade.

In healthy volunteers a 14-day treatment with the selective beta 1-adrenoceptor agonist xamoterol (2 x 200 mg/day) desensitized beta 1-adrenoceptor-mediated physiological effects, but did not affect beta 2-adrenoceptor-mediated effects; in contrast, a 9-day treatment with the selective beta 2-adrenoceptor agonist procaterol (2 x 50 micrograms/day) desensitized beta 1-adrenoceptor-mediated physiological effects, but did not affect beta 1-adrenoceptor-mediated effects suggesting that in general in man long-term treatment with beta-adrenoceptor agonists down-regulates beta-adrenoceptors, but in a beta-adrenoceptor subtype-selective manner. Similarly, in patients undergoing coronary artery bypass grafting chronic treatment with different beta-adrenoceptor antagonists without intrinsic sympathomimetic activity subtype-selectively up-regulated beta-adrenoceptors: non-selective antagonists (propranolol, sotalol) increased both cardiac beta 1- and cardiac, saphenous vein and lymphocyte beta 2-adrenoceptors, whereas beta 1-selective antagonists (metoprolol, atenolol, bisoprolol) increased only cardiac beta 1-, but not cardiac, saphenous vein or lymphocyte beta 2-adrenoceptors. Such a subtype-selective modulation of human beta 1- and beta 2-adrenoceptors should be taken into consideration when treating patients chronically with beta-adrenoceptor agonists and/or antagonists.