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Ge Y, Cai YM, Bonneau L, Rotari V, Danon A, McKenzie EA, McLellan H, Mach L, Gallois P. Correction to: Inhibition of cathepsin B by caspase-3 inhibitors blocks programmed cell death in Arabidopsis. Cell Death Differ 2018; 25:1532. [PMID: 29915277 DOI: 10.1038/s41418-018-0136-1] [Citation(s) in RCA: 3] [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: 11/09/2022] Open
Abstract
We thank D Nicholson for initial advice on caspase activity purification and B Turk for advice on recombinant cathepsin B. We thank N Atanasova for cell death assays. The Bioimaging Facility microscopes used in this study were purchased with grants from BBSRC, Wellcome Trust and the University of Manchester Strategic Fund. Special thanks go to D Knight in the Faculty Biomolecular Analysis facility. We thank P Birch and M Kim for improving the manuscript. The project was partially funded by BBSRC Grants 34/P14516, BB/K009478/1 and China National High-Tech Research and Development Programme(863 programme)NO. 2015AA020903.
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Affiliation(s)
- Y Ge
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,College of Marine Life Science, Ocean University of China, No. 5 Yushan Road, Qingdao, China
| | - Y-M Cai
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - L Bonneau
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,UMR 1347 Agroécologie, INRA, 17 rue Sully, BP 86510, 21065, Dijon Cedex, France
| | - V Rotari
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.,Laboratory of Plant Biochemistry, State University of Moldova, Mateevici street 60, Chisinau, MD-2009, Republic of Moldova
| | - A Danon
- IBPC, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, CNRS, Université Pierre et Marie Curie, FRE3354, 75005, Paris, France
| | - E A McKenzie
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - H McLellan
- Division of Plant Science, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - L Mach
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - P Gallois
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
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Shurrab M, Kaoutskaia A, Arouny B, Lashevsky I, Danon A, Newman D, Kansal N, Schulman S, Healey J, Morillo C, Crystal E. Safety and Efficacy of Dabigatran Compared to Warfarin for Patients Undergoing Radiofrequency Catheter Ablation of Atrial Fibrillation: a Meta-Analysis. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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3
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Attia S, Hevroni L, Danon A, Meyerstein D, Koresh JE, Finkelstein Y. The role of the cation in the oxygen isotopic exchange in crystalline sulfate salt hydrates. ADSORPTION 2013. [DOI: 10.1007/s10450-013-9525-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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4
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Barac DY, Reisner Y, Silberman M, Zeevi-Levin N, Danon A, Salomon O, Shoham M, Shilkrut M, Kostin S, Schaper J, Binah O. Mechanical load induced by glass microspheres releases angiogenic factors from neonatal rat ventricular myocytes cultures and causes arrhythmias. J Cell Mol Med 2009; 12:2037-51. [PMID: 19012730 PMCID: PMC4506169 DOI: 10.1111/j.1582-4934.2008.00193.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In the present study, we tested the hypothesis that similar to other mechanical loads, notably cyclic stretch (simulating pre-load), glass microspheres simulating afterload will stimulate the secretion of angiogenic factors. Hence, we employed glass microspheres (average diameter 15.7 μm, average mass 5.2 ng) as a new method for imposing mechanical load on neonatal rat ventricular myocytes (NRVM) in culture. The collagen-coated microspheres were spread over the cultures at an estimated density of 3000 microspheres/mm2, they adhered strongly to the myocytes, and acted as small weights carried by the cells during their contraction. NRVM were exposed to either glass microspheres or to cyclic stretch, and several key angiogenic factors were measured by RT-PCR. The major findings were: (1) In contrast to other mechanical loads, such as cyclic stretch, microspheres (at 24 hrs) did not cause hypertrophy. (2) Further, in contrast to cyclic stretch, glass microspheres did not affect Cx43 expression, or the conduction velocity measured by means of the Micro-Electrode-Array system. (3) At 24 hrs, glass microspheres caused arrhythmias, probably resulting from early afterdepolarizations. (4) Glass microspheres caused the release of angiogenic factors as indicated by an increase in mRNA levels of vascular endothelial growth factor (80%), angiopoietin-2 (60%), transforming growth factor-β (40%) and basic fibroblast growth factor (15%); these effects were comparable to those of cyclic stretch. (5) As compared with control cultures, conditioned media from cultures exposed to microspheres increased endothelial cell migration by 15% (P<0.05) and endothelial cell tube formation by 120% (P<0.05), both common assays for angiogenesis. In conclusion, based on these findings we propose that loading cardiomyocytes with glass microspheres may serve as a new in vitro model for investigating the role of mechanical forces in angiogenesis and arrhythmias.
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Affiliation(s)
- D Y Barac
- Rappaport Family Institute for Research in the Medical Sciences, Ruth and Bruce Rappaport Faculty of Medicine, Haifa, Israel
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5
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Konson A, Mahajna JA, Danon A, Rimon G, Agbaria R. The involvement of nuclear factor-kappa B in cyclooxygenase-2 overexpression in murine colon cancer cells transduced with herpes simplex virus thymidine kinase gene. Cancer Gene Ther 2006; 13:1093-104. [PMID: 16841079 DOI: 10.1038/sj.cgt.7700983] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have previously reported that transduction of murine colon cancer cells (MC38) with herpes simplex virus thymidine kinase (HSV-tk) gene results in a significant enhancement of tumor growth rate in vivo and overexpression of cyclooxygenase-2 (COX-2). Our current study aimed to investigate the involvement of nuclear factor-kappa B (NF-kappaB), a pivotal transcriptional regulator of COX-2, in the upregulation of COX-2 expression by HSV-tk. It was found that HSV-tk gene transduction of MC38 cells results in significantly enhanced NF-kappaB activity, increased phosphorylation and degradation of inhibitor-kappa Balpha (IkappaBalpha) and enhanced translocation of NF-kappaB to the nucleus. Treatment of HSV-tk-transduced MC38 cells with sulfasalazine, a potent NF-kappaB inhibitor, led to dose-dependent inhibition of NF-kappaB activity, IkappaB phosphorylation and nuclear translocation of NF-kappaB, accompanied by significantly decreased COX-2 expression and reduced release of prostaglandin E2. Transient transfection experiments with COX-2 promoter constructs fused to luciferase reporter gene revealed that mutation in NF-kappaB-responsive element of COX-2 promoter significantly reduced promoter activity in HSV-tk-transduced MC38 and COS-7 cells, whereas it had no effect on promoter activity in the respective wild-type cells. At last, it was found that HSV-tk gene transduction causes significant enhancement of NF-kappaB activity and COX-2 expression in two additional tumor cell lines, 9L and T24. These findings suggest that HSV-tk gene transduction results in NF-kappaB pathway activation, which is essential for COX-2 overexpression by HSV-tk.
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Affiliation(s)
- A Konson
- Department of Clinical Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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6
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Al-Athamen K, Konson A, Rimon G, Danon A, Agbaria R. 51 HSV-tk gene transduction enhances proliferation rate and COX-2 expression in rat gliosarcoma cells. EJC Suppl 2004. [DOI: 10.1016/s1359-6349(04)80059-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Saig A, Danon A, Finkelstein Y, Koresh JE. Selective and reversible entrapment of He and Ne in NaA zeolite at atmospheric pressure. J Chem Phys 2003. [DOI: 10.1063/1.1540612] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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9
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Meiri E, Levitan A, Guo F, Christopher DA, Schaefer D, Zrÿd JP, Danon A. Characterization of three PDI-like genes in Physcomitrella patens and construction of knock-out mutants. Mol Genet Genomics 2002; 267:231-40. [PMID: 11976967 DOI: 10.1007/s00438-002-0658-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2001] [Accepted: 02/08/2002] [Indexed: 11/25/2022]
Abstract
Plant genomes typically contain several sequences homologous to protein disulfide isomerase (PDI). PDI was first identified as an abundant enzyme in the endoplasmic reticulum, where it catalyzes the formation, reduction, and isomerization of disulfide bonds during protein folding. PDI-like proteins have also been implicated in a variety of other functions, such as the regulation of cell adhesion, and may act as elicitors of the autoimmune response in mammals. A PDI-like protein (RB60) was recently shown to be imported into chloroplasts in the unicellular green alga Chlamydomonas reinhardtii and a higher plant, Pisum sativum, where it associates with thylakoid membranes. This suggests that the different PDI-like proteins in plant and animals may have diverse biological roles. To begin to elucidate the roles of PDI-like proteins, we have cloned, characterized, and generated knock-out mutants for three PDI-like genes that have high, medium, and low levels of expression, respectively, in the moss Physcomitrella patens. Phylogenetic analysis indicates that the three PDI-like proteins cluster with RB60 and four proteins from Arabidopsis thaliana. They are typified by an N-terminal domain rich in negatively charged residues. The knock-out mutants, which are the first knock-outs available for PDI-like proteins in a multicellular organism, were found to be viable, indicating that the function of each single gene is dispensable, and suggesting that they may be functionally complementary.
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Affiliation(s)
- E Meiri
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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10
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Trebitsh T, Danon A. Translation of chloroplast psbA mRNA is regulated by signals initiated by both photosystems II and I. Proc Natl Acad Sci U S A 2001; 98:12289-94. [PMID: 11593046 PMCID: PMC59807 DOI: 10.1073/pnas.211440698] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2000] [Accepted: 08/16/2001] [Indexed: 11/18/2022] Open
Abstract
Light controls the translation of several mRNAs in fully developed chloroplasts via at least two regulatory pathways. In the first, the light signal is transduced as a thiol-mediated signal that modulates translation in parallel to light intensity. The second light-controlled pathway, termed priming, is a prerequisite to the thiol-mediated regulatory pathway. Light regulation is rapid and requires intrachloroplast photoreceptor(s). To delineate the signaling pathways controlling each of these regulatory events, we assayed the effect of photosynthetic inhibitors and electron donors on the translation of chloroplastic psbA mRNA. We show that the thiol-mediated signal is generated by photosystem I and transduced by vicinal dithiol-containing proteins. We also found that the priming signal probably initiates on reduction of plastoquinone. These findings suggest that translation of chloroplast psbA mRNA is controlled by both linear photosynthetic electron transport, exerted by the reduction of the ferredoxin-thioredoxin system, and the relative activities of photosystems I and II, signaled by the redox state of the plastoquinone pool. These data underscore the function of the light-capturing reactions of photosynthesis as chloroplast photoreceptors.
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Affiliation(s)
- T Trebitsh
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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11
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Shen Y, Danon A, Christopher DA. RNA binding-proteins interact specifically with the Arabidopsis chloroplast psbA mRNA 5' untranslated region in a redox-dependent manner. Plant Cell Physiol 2001; 42:1071-8. [PMID: 11673622 DOI: 10.1093/pcp/pce142] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The 5' untranslated region (5'UTR) of the psbA mRNA (psbA encodes the PSII reaction center protein, D1) is a key site for RNA-protein interactions in the post-transcriptional regulation of gene expression. In this study, we mapped the major psbA mRNA 5'-terminus at -77 nt, and two minor termini clusters centered at -48 and -64 nt, upstream from the psbA translational start codon of Arabidopsis thaliana. RNA mobility shift, RNase protection and UV-crosslinking assays were used to characterize the interaction of chloroplast proteins with the RNA 5'UTR. RNA-protein interactions depended upon a thermolabile secondary structure and specific sequences in a 35 nt region of the 5'UTR, which were 80% conserved with the psbA 5'UTRs from five other plants. Major and minor proteins of 43- and 30-kDa, respectively, were detected by UV-crosslinking to RNA. Oxidizing conditions abolished the association of the proteins with the 5'UTR, while RNA-binding activity was recovered upon incubation with a reductant. Based on these findings, we hypothesize that post-transcriptional regulation of psbA gene expression in chloroplasts of vascular plants involves redox-dependent interactions between specific sequences in the 5'UTR and 43- and 30-kDa RNA-binding proteins.
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Affiliation(s)
- Y Shen
- Department of Molecular Biosciences and Biosystems Engineering, University of Hawaii, 1955 East-West Road, Honolulu, HI 96822 USA
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12
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Trebitsh T, Meiri E, Ostersetzer O, Adam Z, Danon A. The protein disulfide isomerase-like RB60 is partitioned between stroma and thylakoids in Chlamydomonas reinhardtii chloroplasts. J Biol Chem 2001; 276:4564-9. [PMID: 11087734 DOI: 10.1074/jbc.m005950200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Translation of psbA mRNA in Chlamydomonas reinhardtii chloroplasts is regulated by a redox signal(s). RB60 is a member of a protein complex that binds with high affinity to the 5'-untranslated region of psbA mRNA. RB60 has been suggested to act as a redox-sensor subunit of the protein complex regulating translation of chloroplast psbA mRNA. Surprisingly, cloning of RB60 identified high homology to the endoplasmic reticulum-localized protein disulfide isomerase, including an endoplasmic reticulum-retention signal at its carboxyl terminus. Here we show, by in vitro import studies, that the recombinant RB60 is imported into isolated chloroplasts of C. reinhardtii and pea in a transit peptide-dependent manner. Subfractionation of C. reinhardtii chloroplasts revealed that the native RB60 is partitioned between the stroma and the thylakoids. The nature of association of native RB60, and imported recombinant RB60, with thylakoids is similar and suggests that RB60 is tightly bound to thylakoids. The targeting characteristics of RB60 and the potential implications of the association of RB60 with thylakoids are discussed.
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Affiliation(s)
- T Trebitsh
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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13
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Rosenstock M, Danon A, Rubin M, Rimon G. Prostaglandin H synthase-2 inhibitors interfere with prostaglandin H synthase-1 inhibition by nonsteroidal anti-inflammatory drugs. Eur J Pharmacol 2001; 412:101-8. [PMID: 11166741 DOI: 10.1016/s0014-2999(00)00931-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Ram seminal vesicle microsomes, a rich source of prostaglandin H synthase-1, were incubated with 100 nM of the prostaglandin H synthase-2 inhibitors N-(2-cyclohexyloxy-4-nitrophenyl) methanesulfonamide (NS-398) and 5-bromo-2-(4-fluorophenyl)-3-(4-methylsulfonyl) thiophene (DuP-697) prior to exposure to the prostaglandin H synthase inhibitors aspirin, indomethacin, ibuprofen or naproxen. Activity of the enzyme was measured by following the conversion of arachidonic acid to prostaglandin E(2) and prostaglandin F2alpha. Although prostaglandin H synthase-1 activity was not altered by these concentrations of the prostaglandin H synthase-2 inhibitors, it was found that exposure to these agents prior to aspirin or indomethacin (irreversible prostaglandin H synthase inhibitors) significantly attenuated the inhibition obtained by the latter inhibitors. On the other hand, the same concentrations of the prostaglandin H synthase-2 inhibitors did not interfere with prostaglandin H synthase-1 inhibition that was induced by naproxen or ibuprofen (competitive prostaglandin H synthase inhibitors). Attenuation of the indomethacin inhibition of prostaglandin H synthase-1 by prostaglandin H synthase-2 inhibitors was observed only when the microsomes were pre-exposed to DuP-697 or NS-398 in the absence, but not in the presence, of arachidonic acid. The effect of DuP-697 was found to be irreversible, however, washing away the agent reversed the action of NS-398. Similar phenomena have been reported by us in bovine aortic endothelial cells and in human dermal fibroblasts. Attenuation of the inhibition by aspirin and indomethacin, without altering the enzyme's basal activity or the inhibition induced by ibuprofen or naproxen may suggest the possibility that the prostaglandin H synthase-2 specific inhibitors DuP-697 and NS-398 affect prostaglandin H synthase-1 by interaction with a site different from the enzyme's catalytic site.
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Affiliation(s)
- M Rosenstock
- Department of Clinical Pharmacology, The Corob Center for Health Sciences, Faculty of Health Sciences, Ben-Gurion University of the Negev and Soroka Medical Center, P.O. Box. 653, 84105, Beer-Sheva, Israel
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Trebitsh T, Levitan A, Sofer A, Danon A. Translation of chloroplast psbA mRNA is modulated in the light by counteracting oxidizing and reducing activities. Mol Cell Biol 2000; 20:1116-23. [PMID: 10648596 PMCID: PMC85229 DOI: 10.1128/mcb.20.4.1116-1123.2000] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Light has been proposed to stimulate the translation of Chlamydomonas reinhardtii chloroplast psbA mRNA by activating a protein complex associated with the 5' untranslated region of this mRNA. The protein complex contains a redox-active regulatory site responsive to thioredoxin. We identified RB60, a protein disulfide isomerase-like member of the protein complex, as carrying the redox-active regulatory site composed of vicinal dithiol. We assayed in parallel the redox state of RB60 and translation of psbA mRNA in intact chloroplasts. Light activated the specific oxidation of RB60, on the one hand, and reduced RB60, probably via the ferredoxin-thioredoxin system, on the other. Higher light intensities increased the pool of reduced RB60 and the rate of psbA mRNA translation, suggesting that a counterbalanced action of reducing and oxidizing activities modulates the translation of psbA mRNA in parallel with fluctuating light intensities. In the dark, chemical reduction of the vicinal dithiol site did not activate translation. These results suggest a mechanism by which light primes redox-regulated translation by an unknown mechanism and then the rate of translation is determined by the reduction-oxidation of a sensor protein located in a complex bound to the 5' untranslated region of the chloroplast mRNA.
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Affiliation(s)
- T Trebitsh
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
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15
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Rosenstock M, Danon A, Rimon G. PGHS-2 inhibitors, NS-398 and DuP-697, attenuate the inhibition of PGHS-1 by aspirin and indomethacin without altering its activity. Biochim Biophys Acta 1999; 1440:127-37. [PMID: 10477832 DOI: 10.1016/s1388-1981(99)00105-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Since the discovery of the inducible form of prostaglandin (PG) H synthase (PGHS), PGHS-2, considerable effort has been made to design selective inhibitors of this isozyme. N-(2-cyclohexyloxy-4-nitrophenyl) methanesulfonamide (NS-398) and 5-bromo-2-(4-fluorophenyl)-3-(4-methylsulfonyl) thiophene (DuP-697) have been shown to interact reversibly with PGHS-1, while irreversibly inhibiting PGHS-2 in a time-dependent manner. In the present study we have tested the effects of DuP-697 and NS-398 on the activity of PGHS-1 and further explored the interactions between these agents and the inhibition of PGHS-1 by aspirin, indomethacin and ibuprofen. Three independent experimental systems, namely bovine aortic endothelial cells (BAEC), human fibroblasts and ram seminal vesicle microsomes were used to investigate the effects of DuP-697 and NS-398 on PGHS-1. The results show that DuP-697 and NS-398, at concentrations ranges which do not inhibit PGHS-1 activity, significantly attenuated the inhibition of PGHS-1 that was caused by aspirin and indomethacin. The same concentrations of DuP-697 and NS-398 did not affect the inhibition of PGHS-1 that was induced by the competitive reversible inhibitors ibuprofen and naproxen. Similar effects of DuP-697 and NS-393 were obtained with ram seminal vesicle microsomes. These results suggest that PGHS-2 inhibitors DuP-697 and NS-398 possibly interact with PGHS-1 at a site different from the enzyme's catalytic site, thus causing attenuation of PGHS-1 inhibition by aspirin and indomethacin without altering PGHS-1 basal activity or the ibuprofen-induced inhibition.
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Affiliation(s)
- M Rosenstock
- Department of Clinical Pharmacology, The Corob Center for Health Sciences, Ben-Gurion University and Soroka Medical Center, P.O. Box 653, Beer-Sheva, Israel
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16
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Abstract
Bovine aortic endothelial cells produce prostacyclin as their major arachidonic acid metabolite. cAMP, in turn, is the second messenger for prostacyclin. In the present study, we investigated the effects of cAMP-elevating agents on prostacyclin production by bovine aortic endothelial cells. Treatment of resting bovine aortic endothelial cells with cAMP-elevating agents inhibited prostacyclin production and cyclooxygenase activity, without affecting arachidonic acid release. No change was detected in cyclooxygenase-1 protein expression. The specific inhibitor of protein kinase A, Rp-cAMPS (adenosine 3',5'-cyclic monophosphorothioate, Rp-isomer, triethylammonium salt), and the phosphatase inhibitor, okadaic acid, both suppressed cAMP-induced inhibition, suggesting that this inhibition is mediated by a phosphorylation-dephosphorylation cascade, which is possibly protein kinase A-dependent. In lipopolysaccharide-treated cyclooxygenase-2 expressing bovine aortic endothelial cells, where cyclooxygenase-1 activity was selectively inhibited, dibutyryl cAMP failed to inhibit cyclooxygenase-2 activity. Cyclooxygenase-2 protein was induced upon treatment with dibutyryl cAMP and further induction of cyclooxygenase-2 protein was effected by IBMX (3-isobutyl-1-methyl-xanthine) and dibutyryl cAMP in bacterial lipopolysaccharide-stimulated cells. These results suggest that increased cellular cAMP selectively inhibits cyclooxygenase-1 activity without altering cyclooxygenase-1 protein expression, and at the same time, up-regulates cyclooxygenase-2 protein. This complex regulation of cyclooxygenase activity and protein expression by cAMP may represent a prostacyclin-induced autoregulatory mechanism in bovine aortic endothelial cells.
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Affiliation(s)
- A Samokovlisky
- Department of Clinical Pharmacology, The Corob Center for Health Sciences, Ben-Gurion University, Beer Sheva, Israel
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17
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Abstract
Interleukin (IL)-1alpha and IL-1beta share low amino acid homology, but exhibit a very similar array of biological activities. The authors previously showed negative regulation of IL-1alpha-induced prostaglandin (PG) production by corticotropin releasing factor (CRF). In this study, the authors compared the effect of CRF on IL-1alpha- and IL-1beta-induced PG synthesis. IL-1alpha (100 U/ml) increased prostacyclin (PGI2) (measured as 6-keto PGF1alpha[6K]) synthesis in endothelial cells and the production of PGE2in fibroblasts. The PG response to IL-1alpha was suppressed by simultaneous exposure to CRF (2.5x10(-11)-2.5x10(-8) M) in both cell types. IL-1alpha enhanced both phospholipase A2(PLA2) and prostaglandin H synthase (PGHS) activities, and the two effects were completely abrogated by CRF. IL- 1beta (100 U/ml) was as active as IL-1alpha in triggering release of PGI2 from endothelial cells and PGE2 from fibroblasts. However, CRF (2.5x10(-11)-2.5x10(-8) M) failed to alter the IL-1beta-induced PG synthesis in both cell types. Following IL-1beta PGHS activity, and to a lesser extent PLA2 activity, were enhanced, however CRF only inhibited PGHS and not PLA2 activity. It is concluded that although IL-1alpha and IL-1beta usually produce similar biological effects, here they seem to act via different mechanisms. The different regulation of IL-1alpha and IL-1beta pro-inflammatory activities by CRF may attribute special precision and specificity to the neuroendocrine-immune control of inflammatory processes.
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Affiliation(s)
- S Fleisher-Berkovich
- Department of Clinical Pharmacology, The Corob Center of Health Sciences, Ben-Gurion University and Soroka Medical Center, Beer-Sheva, 84105, Israel
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18
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Abstract
With a view to studying programmed cell death in plants at the molecular level, we report here for the first time that apoptotic-like changes are induced by UV radiation in plant nuclei. In Arabidopsis thaliana seedlings a UV-C dose of 10-50 kJ/m2 induces an oligonucleosomal DNA fragmentation which is reminiscent of the apoptotic DNA ladder described in animal cells. This DNA fragmentation was also detected in situ in protoplast nuclei as soon as 2 h after UV-C treatment. Moreover, UV-C induced a nuclear morphology characteristic of animal apoptotic nuclei. We propose that UV-C induction constitutes a powerful tool to compare the cellular response to irreversible UV damage in plants to that in animals and to study programmed cell death in A. thaliana.
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Affiliation(s)
- A Danon
- Laboratoire de Physiologie et Biologie Moléculaire des Plantes, UMR CNRS 5545, Université de Perpignan, France
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Fleisher-Berkovich S, Rimon G, Danon A. Corticotropin releasing factor modulates interleukin-1-induced prostaglandin synthesis in fibroblasts: receptor binding and effects of antagonists. Regul Pept 1998; 77:121-6. [PMID: 9809805 DOI: 10.1016/s0167-0115(98)00107-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Corticotropin releasing factor (CRF) is a predominant regulator of the neuroendocrine, autonomic and behavioral responses to stress. In addition, numerous studies support autocrine/paracrine roles for this peptide at peripheral sites. CRF and CRF binding sites have been identified in different regions of the central nervous system as well as in the heart, spleen, adrenal and testis, and high levels of CRF were detected in inflamed fibroblasts. However, the precise physiological or pathophysiological role of peripheral CRF cannot yet be discerned. Here we show that CRF, through interaction with specific membrane receptors, blocks the interleukin-1alpha (IL-1alpha)-stimulated prostaglandin (PG) synthesis in fibroblasts. Binding of [125I]-labeled CRF in fibroblasts was saturable and fitted a two sites model. K(D) for the higher-affinity class of receptors was 20+/-2.2 pM, and Bmax 1.95+/-0.22 fmol/mg protein. For the lower-affinity class of receptors K(D) was 160+/-17 nM, and Bmax 2.38+/-0.27 fmol/mg protein. CRF blocked the effect of IL-1alpha on PGE2 synthesis, and this was antagonised by D-PheCRF12-41. In addition, the CRF receptor antagonists alpha helical CRF9-41 and D-PheCRF12-41 at high concentrations inhibited the IL-1alpha-induced PG synthesis similarly to CRF, suggesting partial agonistic action. Taken together, these results suggest a modulatory role of CRF in inflammation.
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Affiliation(s)
- S Fleisher-Berkovich
- Department of Clinical Pharmacology, Corob Center for Health Sciences, Ben-Gurion University and Soroka Medical Center, Beer-Sheva, Israel
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Abstract
Corticotropin releasing factor (CRF) is a hypothalamic hormone that also displays autocrine/paracrine roles at peripheral sites. High concentrations of CRF have been identified in endothelial cells and other inflammatory tissues. We investigated the effects of CRF and antagonists in the regulation of prostaglandin synthesis in bovine aortic endothelial cells, and also characterized the binding of CRF in these cells. Interleukin-1alpha increased prostacyclin (prostaglandin I2) synthesis in endothelial cells and this response to interleukin-1alpha was abolished by simultaneous exposure to CRF. The effect of CRF on interleukin-1alpha-induced prostaglandin synthesis was antagonised by the CRF receptor antagonist alpha-helical CRF-(9-41). In addition, this as well as another CRF receptor antagonist, namely [D-Phe12]CRF-(12-41), when applied alone at low concentrations inhibited the interleukin-1alpha-induced prostaglandin synthesis similarly to CRF, suggesting partial agonistic action. Binding of [125I]-labeled CRF in endothelial cells was saturable and fitted a two sites model. Kd for the higher-affinity class of receptors was 0.2 +/- 0.02 nM, and Bmax 0.79 +/- 0.095 fmol/mg protein. The lower-affinity class of receptors had a Kd of 1.77 +/- 0.14 microM and Bmax 0.97 +/- 0.12 fmol/mg protein. These findings suggest a direct role for CRF in the local regulation of inflammation.
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Affiliation(s)
- S Fleisher-Berkovich
- Department of Clinical Pharmacology, Corob Center for Health Sciences, Ben-Gurion University and Soroka Medical Center, Beer-Sheva, Israel
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21
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Abstract
OBJECTIVE We have recently reported a large cluster of patients with nephrogenic diabetes insipidus (NDI) due to an autosomal recessive aquaporin-2 (AQP-2) early-stop codon. This paper describes the clinical manifestations and evaluation of therapeutic approaches to this new entity. PATIENTS AND DESIGN Nine patients with an AQP-2 mutation were studied. Urine osmolality was measured in five patients before and at 3 x 30 min intervals after desmopressin given in increasing doses of 5-100 micrograms. Urinary prostaglandins PGE2 and 6-keto PGF1 alpha, were extracted from 24-h urine samples and estimated by radioimmunoassays. Eight NDI patients were given a combination of a low-sodium diet and hydrochlorothiazide. Four to 11 weeks later, ibuprofen was added, and the patients were retested within the following 4-9 weeks. RESULTS Urine osmolality remained unchanged after supra-pharmacological doses of desmopressin, at 60-70 mOsm/kg. Urinary PGE2 in control subjects was 0.74 +/- 0.1 microgram/g creatinine (mean +/- SD) compared to 5.0 +/- 2.6 micrograms/g creatinine in AQP-2 deficient patients (P < 0.05). Urinary 6-keto PGF1 alpha, was 0.20 +/- 0.03 microgram/g creatinine in controls and 0.75 +/- 0.31 microgram/g creatinine in AQP-2 deficiency (P < 0.05). Urinary volumes decreased by a mean 31% on a low-salt diet and hydrochlorothiazide, and by a mean of 38% on the combination therapy. Plasma osmolality decreased by a mean 15 mOsm/kg on the low-salt diet and hydrochlorothiazide, and by 22 mOsm/kg on the combination therapy. Urinary osmolality increased from a mean 80 mOsm/kg to 96 mOsm/kg on the low-salt diet and hydrochlorothiazide, and to 146 mOsm/kg on the combination therapy. CONCLUSION AQP-2 deficiency in these patients with an early-stop codon is associated with complete unresponsiveness of the collecting duct to vasopressin, implying an indispensable role for AQP-2 in vasopressin antidiuresis. Urinary PGE2 and 6-keto PGF1 alpha are elevated, the former being extremely high, apparently due to the extreme vasopressin unresponsiveness. Combination therapy with a combination of a low-salt diet, thiazide and non-steroidal anti-inflammatory drug is partially effective.
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Affiliation(s)
- Z Hochberg
- Department of Pediatrics, Rambam Medical Center, Haifa, Israel.
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22
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Fleisher-Berkovich S, Danon A. Differential effect of corticotropin releasing factor on interleukin-1 alpha and interleukin-1 beta-induced prostaglandin synthesis in endothelial cells and fibroblasts. Adv Exp Med Biol 1998; 433:255-8. [PMID: 9561147 DOI: 10.1007/978-1-4899-1810-9_54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- S Fleisher-Berkovich
- Department of Clinical Pharmacology, Corob Center of Health Sciences, Ben-Gurion University and Soroka Medical Center, Beer-Sheva, Israel
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23
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Yohn CB, Cohen A, Danon A, Mayfield SP. A poly(A) binding protein functions in the chloroplast as a message-specific translation factor. Proc Natl Acad Sci U S A 1998; 95:2238-43. [PMID: 9482869 PMCID: PMC19305 DOI: 10.1073/pnas.95.5.2238] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.3] [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] [Received: 12/04/1997] [Accepted: 12/20/1997] [Indexed: 02/06/2023] Open
Abstract
High-affinity binding of a set of proteins with specificity for the 5' untranslated region (UTR) of the Chlamydomonas reinhardtii chloroplast psbA mRNA correlates with light-regulated translational activation of this message. We have isolated a cDNA encoding the main psbA RNA binding protein, RB47, and identified this protein as a member of the poly(A) binding protein family. Poly(A) binding proteins are a family of eukaryotic, cytoplasmic proteins thought to bind poly(A) tails of mRNAs and play a role in translational regulation. In vitro translation of RNA transcribed from the RB47 cDNA produces a precursor protein that is efficiently transported into the chloroplast and processed to the mature 47-kDa protein. RB47 expressed and purified from Escherichia coli binds to the psbA 5' UTR with similar specificity and affinity as RB47 isolated from C. reinhardtii chloroplasts. The identification of a normally cytoplasmic translation factor in the chloroplast suggests that the prokaryotic-like chloroplast translation machinery utilizes a eukaryotic-like initiation factor to regulate the translation of a key chloroplast mRNA. These data also suggest that poly(A) binding proteins may play a wider role in translation regulation than previously appreciated.
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Affiliation(s)
- C B Yohn
- Department of Cell Biology and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Affiliation(s)
- A Danon
- Department of Plant Genetics, Weizmann Institute of Science, Rehovot, Israel.
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26
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Abstract
The objective of the present study was to examine whether prostaglandin H synthase (PGHS) can be regulated by pathways independent of de novo synthesis of PGHS. Incubation of bovine aortic endothelial cells (BAEC) for as short as 5 min with NaF (40 mM) resulted in a 60% increase in PGHS activity. PGHS activity induced by NaF was unaffected by either 10 microM cycloheximide or 1 microM actinomycin D. Aspirin (25 microM) completely inhibited resting PGHS activity, and NaF did not induce further stimulation. NS-398 (500 nM), a specific PGHS-2 inhibitor, was ineffective. Basic fibroblast growth factor (bFGF) induced a significant increase in PGHS activity within 30 min and was insensitive to cycloheximide. The levels of PGHS-1 and PGHS-2 proteins, as measured by Western blots, were not affected by NaF or bFGF. The tyrosine kinase inhibitor genistein attenuated PGHS activity that was induced by NaF and bFGF, whereas the tyrosine phosphatase inhibitor, sodium orthovanadate, augmented these responses. The G protein activators 5'-guanylyl imidodiphosphate and guanosine 5'-O-(3-thiotriphosphate) inhibited both resting and NaF-induced PGHS activities. These results suggest-that, in BAEC, PGHS-1 activity can be regulated by tyrosine kinase and/or G proteins, independently of de novo protein synthesis.
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Affiliation(s)
- M Rosenstock
- Department of Clinical Pharmacology, Corob Center for Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
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27
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Barak J, Mankuta D, Pak I, Glezerman M, Katz M, Danon A. Transabdominal amnioinfusion of gentamicin: A pharmakokinetic study of maternal plasma and intraamniotic levels. Am J Obstet Gynecol 1997. [DOI: 10.1016/s0002-9378(97)80248-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
The respective roles of protein kinase C (PKC) and intracellular calcium concentration ([Ca2+]i) in glucocorticoid (GC) action on prostacyclin (PGl2) production by bovine aortic endothelial cells (BAEC) were investigated. Twenty-four hours' pretreatment with dexamethasone (DEX, 10(-6) diminished the response of BAEC to calcium ionophore A23187 (0.001-1 micrograms/ml) and ionomycin (3 microM) by about 50%, as assessed by both PGl2 release and [Ca2+]i elevation. Contrary to control cells, in DEX-penetrated cells short treatment with 12-O-tetradecanoyl phorbol 13-acetate (100 nM) significantly decreased PGl2 production without affecting cyclooxygenase activity. The data suggest that the mechanism of action of GC involves both pathways of intracellular signal transduction, namely the rises in both [Ca2+]i and PKC activity. These actions of DEX may be attributed to a phospholipase A2-inhibiting protein, such as lipocortin, which accumulates during exposure to DEX. Binding of a sufficient fraction of calcium ions and phosphorylation by PKC might be the events needed fro lipocortin activation.
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Affiliation(s)
- M Rosenstock
- Department of Clinical Pharmacology, Corob Center of Health Sciences, Ben-Gurion University, Beer Sheva, Israel
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29
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Abstract
NaF, a nonselective activator of heterotrimeric guanine nucleotide-binding proteins (G proteins), increased the release of arachidonic acid (AA) and prostacyclin (PGI2) production in bovine aortic endothelial cells (BAEC) at low concentrations (40-60 mM). On the other hand, higher concentrations (100 mM) inhibited phospholipase A2 (PLA2) compared with the basal activity. Intracellular Ca2+ levels did not rise after treatment with stimulatory concentrations of NaF, and, moreover, neither neomycin nor Ca(2+)-free medium affected the biphasic pattern of PGI2 synthesis in response to NaF. CGP-43187, an inhibitor of the 14-kDa secretory PLA2, did not affect NaF-induced AA release. However, AACOCF3, a specific inhibitor of the cytosolic 85-kDa PLA2 (cPLA2), abrogated AA release and PGI2 production in response to 60 mM NaF. A biphasic pattern of PGI2 production was also obtained with the guanosine 5'-triphosphate analogues guanosine 5'-O-(3-thiotriphosphate) and guanylylimidodiphosphate in permeabilized BAEC. Pretreatment of the cells with guanosine 5'-O-(2-thiodiphosphate) suppressed the inhibition and the stimulation of AA release induced by guanylylimidodiphosphate. In addition, phenylisopropyl adenosine inhibited the release of AA and PGI2, whereas ATP and bradykinin increased PGI2. Pertussis toxin not only inhibited ATP- and bradykinin-stimulated PGI2 release, it also reversed the inhibitory effect of phenylisopropyl adenosine, resulting in a significant stimulation. These findings strongly suggest that, in BAEC, cPLA2 is coupled with more than one G protein that are involved in inhibition and stimulation of cPLA2 activity.
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Affiliation(s)
- M Rosenstock
- Department of Clinical Pharmacology, Corob Center for Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
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30
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Yohn CB, Cohen A, Danon A, Mayfield SP. Altered mRNA binding activity and decreased translational initiation in a nuclear mutant lacking translation of the chloroplast psbA mRNA. Mol Cell Biol 1996; 16:3560-6. [PMID: 8668172 PMCID: PMC231351 DOI: 10.1128/mcb.16.7.3560] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [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: 02/01/2023] Open
Abstract
Translational regulation has been identified as one of the key steps in chloroplast-encoded gene expression. Genetic and biochemical analysis with Chlamydomonas reinhardtii has implicated nucleus-encoded factors that interact specifically with the 5' untranslated region of chloroplast mRNAs to mediate light-activated translation. F35 is a nuclear mutation in C. reinhardtii that specifically affects translation of the psbA mRNA (encoding D1, a core polypeptide of photosystem II), causing a photosynthetic deficiency in the mutant strain. The F35 mutant has reduced ribosome association of the psbA mRNA as a result of decreased translation initiation. This reduction in ribosome association correlates with a decrease in the stability of the mRNA. Binding activity of the psbA specific protein complex to the 5' untranslated region of the mRNA is diminished in F35 cells, and two members of this binding complex (RB47 and RB55) are reduced compared with the wild type. These data suggest that alteration of members of the psbA mRNA binding complex in F35 cells results in a reduction in psbA mRNA-protein complex formation, thereby causing a decrease in translation initiation of this mRNA.
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Affiliation(s)
- C B Yohn
- Division of Plant Biology, Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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31
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Sagi A, Silkovsky J, Fleisher-Berkovich S, Danon A, Chayoth R. Prostaglandin E2 in previtellogenic ovaries of the prawn Macrobrachium rosenbergii: synthesis and effect on the level of cAMP. Gen Comp Endocrinol 1995; 100:308-13. [PMID: 8775057 DOI: 10.1006/gcen.1995.1161] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Eicosanoids are thought to play a role in the regulation of invertebrate reproduction, as they do in vertebrate systems. This was investigated using the previtellogenic ovary of the freshwater prawn Macrobrachium rosenbergii as a biological model. Concentrations of prostaglandin E2 (PGE2), assessed by means of radioimmunoassay, in the previtellogenic ovary (oocyte diameter 20-40 microns) were 32.4 +/- 14.1 pg/mg ovary. Preincubation of the ovary with indomethacin (10 microM) inhibited PGE2 synthesis by 43%. In addition, if indomethacin was added to the culture medium, cAMP levels decreased by 48%. When previtellogenic ovaries were incubated in vitro with PGE2 (0.05 micrograms/ml medium and up), cAMP levels in the tissue homogenate sharply increased. The levels of cAMP rose most significantly (up to 10-fold) when 1-10 micrograms PGE2/ml medium was applied. These results suggest that PGE2, and possibly other prostaglandins, may play a role in the endocrine regulation of crustacean reproduction.
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Affiliation(s)
- A Sagi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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32
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Abstract
Recent evidence suggests that not only the end product of the hypothalamic-pituitary-adrenal axis, but also other hormones in the axis may be involved in regulation of the inflammatory response. We investigated the role of CRF in the regulation of prostaglandin (PG) synthesis in fibroblasts and endothelial cells. Recombinant human interleukin-1 alpha (IL-1 alpha) increased prostacyclin synthesis in endothelial cells by 66% and prostaglandin E2 (PGE2) synthesis in fibroblasts by 91%. The PG response to IL-1 alpha was suppressed to about 50% by simultaneous addition of CRF in endothelial cells (75.6 +/- 6.2 vs. 159.7 +/- 14.9 ng 6-keto-PGF1 alpha/mg protein) and fibroblasts (115.5 +/- 23 vs. 233.6 +/- 42 ng PGE2/mg protein). IL-1 alpha enhanced phospholipase A2 activity by 30% and prostaglandin H synthase activity by 60%, and the two effects were completely blocked by CRF. It is concluded that CRF suppresses IL-1 alpha-induced PG synthesis through actions on both phospholipase A2 and cyclooxygenase. In view of the essential role of central PGE2 in IL-1 alpha-induced CRF/ACTH release, these findings suggest a novel regulatory cascade in immune-neuroendocrine interactions.
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Affiliation(s)
- S Fleisher-Berkovich
- Department of Clinical Pharmacology, Corob Center of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel
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Rosenstock M, Rimon G, Danon A. Dual regulation of phospholipase A2 by GTP-analogs and sodium fluoride in endothelial cells. Pharmacol Res 1995. [DOI: 10.1016/1043-6618(95)87097-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Fleisher-Berkovich S, Grossman N, Goren R, Danon A. Effect of corticotropin releasing factor on prostaglandin synthesis in endothelium and fibroblasts. Pharmacol Res 1995. [DOI: 10.1016/1043-6618(95)86586-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Abstract
Translation of key proteins in the chloroplast is regulated by light. Genetic and biochemical studies in the unicellular alga Chlamydomonas reinhardtii suggest that light may regulate translation by modulating the binding of activator proteins to the 5' untranslated region of chloroplast messenger RNAs. In vitro binding of the activator proteins to psbA messenger RNA and in vivo translation of psbA messenger RNA is regulated by the redox state of these proteins, suggesting that the light stimulus is transduced by the photosynthesis-generated redox potential.
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Affiliation(s)
- A Danon
- Department of Cell Biology, Scripps Research Institute, La Jolla, CA 92037
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37
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Mayfield SP, Cohen A, Danon A, Yohn CB. Translation of the psbA mRNA of Chlamydomonas reinhardtii requires a structured RNA element contained within the 5' untranslated region. J Biophys Biochem Cytol 1994; 127:1537-45. [PMID: 7798310 PMCID: PMC2120278 DOI: 10.1083/jcb.127.6.1537] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Translational regulation is a key modulator of gene expression in chloroplasts of higher plants and algae. Genetic analysis has shown that translation of chloroplast mRNAs requires nuclear-encoded factors that interact with chloroplastic mRNAs in a message-specific manner. Using site-specific mutations of the chloroplastic psbA mRNA, we show that RNA elements contained within the 5' untranslated region of the mRNA are required for translation. One of these elements is a Shine-Dalgarno consensus sequence, which is necessary for ribosome association and psbA translation. A second element required for high levels of psbA translation is located adjacent to and upstream of the Shine-Dalgarno sequence, and maps to the location on the RNA previously identified as the site of message-specific protein binding. This second element appears to act as a translational attenuator that must be overcome to activate translation. Mutations that affect the secondary structure of these RNA elements greatly reduce the level of psbA translation, suggesting that secondary structure of these RNA elements plays a role in psbA translation. These data suggest a mechanism for translational activation of the chloroplast psbA mRNA in which an RNA element containing the ribosome-binding site is bound by message-specific RNA binding proteins allowing for increased ribosome association and translation initiation. These elements may be involved in the light-regulated translation of the psbA mRNA.
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Affiliation(s)
- S P Mayfield
- Department of Cell Biology, Scripps Research Institute, La Jolla, California 92037
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38
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Abstract
Light-regulated translation of chloroplastic mRNAs in the green alga Chlamydomonas reinhardtii requires nuclear encoded factors that interact with the 5'-untranslated region (5'-UTR) of specific mRNAs to enhance their translation. We have previously identified and characterized a set of proteins that bind specifically to the 5'-UTR of the chloroplastic psbA mRNA. Accumulation of these proteins is similar in dark- and light-grown cells, whereas their binding activity is enhanced during growth in the light. We have identified a serine/threonine protein phosphotransferase, associated with the psbA mRNA-binding complex, that utilizes the beta-phosphate of ADP to phosphorylate and inactivate psbA mRNA-binding in vitro. The inactivation of mRNA-binding in vitro is initiated at high ADP levels, levels that are attained in vivo only in dark-grown chloroplasts. These data suggest that the translation of psbA mRNA is attenuated by phosphorylation of the mRNA-binding protein complex in response to a rise in the stromal concentration of ADP upon transfer of cells to dark.
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Affiliation(s)
- A Danon
- Department of Cell Biology, Scripps Research Institute, La Jolla, CA 92037
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39
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Cohen-Luria R, Danon A, Rimon G. Cytosolic proteins alter the properties of the prostaglandin E2 receptor in rat epididymal adipocytes. Prostaglandins 1993; 45:501-7. [PMID: 8393204 DOI: 10.1016/0090-6980(93)90013-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- R Cohen-Luria
- Department of Physiology, Ben Gurion University of Negev, Beer Sheva, Israel
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40
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Abstract
Body reaction to injury comprises two major pathways: the immune response, predominantly mediated by IL-1 and other cytokines, and neuroendocrine mechanisms, resulting in an increased glucocorticoid production. Each has distinct effects on prostaglandin (PG) production, which may in turn mediate both systemic and local inflammatory responses. The interactions, if any, between the two systems on PG synthesis have not been studied. Bovine aortic endothelial cell cultures were used and prostacyclin (PGI2) production was monitored. Cells were treated with dexamethasone (Dex) 10(-6) M and IL-1 10-30 U/ml in one experiment, and lipopolysaccharide (LPS, 0.1-1.0 micrograms/ml) in another experiment, separately or in combination, for either 2 or 24 + 2 h. While Dex was without effect, IL-1 and LPS stimulated PGI2 in a concentration- and time-dependent manner. Short exposure to Dex (2 h) enhanced the stimulation by IL-1 and LPS. On the contrary, more prolonged exposure (24 + 2 h) reversed the effects of IL-1 and LPS, resulting in PGI2 levels below the baseline. A biphasic regulation by Dex was also observed with increasing concentrations of LPS. Dex was actually ineffective by itself, but it enhanced PGI2 production in combination with lower concentrations of LPS, while abolishing the influence of higher concentrations of this agonist. The data suggest that Dex may initially stimulate phospholipase A2 (PLA2) activity, while inhibiting it later. This biphasic behavior may be attributed to different concentrations of a PLA2-modulating protein, possibly lipocortin, that accumulate during exposure to Dex.
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Affiliation(s)
- G Prajgrod
- Dept. of Clinical Pharmacology, Corob Center of Health Sciences, Ben-Gurion University, Beer Sheva, Israel
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41
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Abstract
Body reaction to injury comprises two major pathways: the immune response is predominantly mediated by IL-1 and other cytokines, and neuroendocrine mechanisms, resulting in increased glucocorticoid production. Each has distinct effects on prostaglandin (PG) production, which may in turn mediate both systemic and local inflammatory responses. The interactions, if any, between the two systems on PG synthesis have not been studied. Bovine aortic endothelial cell cultures were used and prostacyclin (PGI2) production was monitored. Cells were treated with dexamethasone (Dex) 10(-6) M and IL-1 10-30 U/ml in one experiment, and lipopolysaccharide (LPS, 0.1-1.0 microgram/ml) in another experiment, separately or in combination, for either 2 or 24 + 2 h. While Dex was without effect, IL-1 and LPS stimulated PGI2 in a concentration and time dependent manner. Short exposure to Dex (2 h) enhanced the stimulation by IL-1 and LPS. On the contrary, more prolonged exposure (24 + 2 h) reversed the effects of IL-1 and LPS, resulting in PGI2 levels below baseline. A biphasic regulation by Dex was also observed with increasing concentrations of LPS. Dex was actually ineffective by itself, but it enhanced PGI2 production in combination with lower concentrations of LPS, while abolishing the influence of higher concentrations of this agonist. The data suggest that Dex may initially stimulate phospholipase A2 (PLA2) activity, while inhibiting it later. This biphasic behavior may be attributed to different concentrations of a PLA2-modulating protein, possibly lipocortin, that accumulate during exposure to Dex.
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Affiliation(s)
- G Prajgrod
- Dept. of Clinical Pharmacology, Corob Center of Health Sciences, Ben-Gurion University, Beer Sheva, Israel
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42
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Abstract
Genetic analysis has revealed a set of nuclear-encoded factors that regulate chloroplast mRNA translation by interacting with the 5' leaders of chloroplastic mRNAs. We have identified and isolated proteins that bind specifically to the 5' leader of the chloroplastic psbA mRNA, encoding the photosystem II reaction center protein D1. Binding of these proteins protects a 36 base RNA fragment containing a stem-loop located upstream of the ribosome binding site. Binding of these proteins to the psbA mRNA correlates with the level of translation of psbA mRNA observed in light- and dark-grown wild type cells and in a mutant that lacks D1 synthesis in the dark. The accumulation of at least one of these psbA mRNA-binding proteins is dependent upon chloroplast development, while its mRNA-binding activity appears to be light modulated in developed chloroplasts. These nuclear encoded proteins are prime candidates for regulators of chloroplast protein synthesis and may play an important role in coordinating nuclear-chloroplast gene expression as well as provide a mechanism for regulating chloroplast gene expression during development in higher plants.
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Affiliation(s)
- A Danon
- Department of Cell Biology, Scripps Research Institute, La Jolla, CA 92037
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Abstract
Prostaglandins (PGs) are believed to be involved in some of the manifestations of the acute phase response, which may be triggered by bacterial lipopolysaccharide (LPS). Glucocorticoids are part of this response and, among other things, regulate PG synthesis and are anti-inflammatory. We investigated the role of endogenous and exogenous glucocorticoids in the regulation of aortic prostacyclin synthesis and in its response to LPS. Rats were injected with LPS and their aorta incubated ex vivo. Aortic prostacyclin (PGI2) production declined 1 h after LPS injection and remained low for at least 96 h. On the other hand, LPS stimulated PGI2 production in adrenalectomized rats, although the latter had reduced capacity to synthesize PGI2, compared with sham-operated rats. Dexamethasone substitution restored synthesis. In intact rats only acute (2 h), but not repeated administration of dexamethasone, increased PGI2 production. In vitro IL-1 alpha stimulated aortic PGI2 synthesis. It is concluded that glucocorticoids may exert a biphasic influence on aortic PGI2 production, possibly through a dual action of lipocortins. Moreover, it is suggested that lipocortin requires activation before it can exert its full effect, and that agonists such as LPS may provide the stimulus for such activation.
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Affiliation(s)
- A Danon
- Dept. of Clinical Pharmacology, Corob Center of Health Sciences, Ben-Gurion University, Beer Sheva, Israel
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Shainkin-Kestenbaum R, Berlyne G, Zimlichman S, Sorin HR, Nyska M, Danon A. Acute phase protein, serum amyloid A, inhibits IL-1- and TNF-induced fever and hypothalamic PGE2 in mice. Scand J Immunol 1991; 34:179-83. [PMID: 1714101 DOI: 10.1111/j.1365-3083.1991.tb01535.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effect of serum amyloid A (SAA) on fever induced by recombinant interleukin-1 beta (rIL-1 beta) or recombinant tumour necrosis factor alpha (rTNF alpha) was studied in mice. Serum amyloid A is an acute phase protein whose rise in pathological events is induced by the cytokines IL-1, IL-6 and TNF. Administration of human serum amyloid A to mice inhibited fever induced by rIL-1 beta or rTNF alpha in vivo, while the addition of human serum amyloid A to mice hypothalamic slices inhibited IL-1 beta- or TNF alpha-induced prostaglandin E2 (PGE2) production in vitro. Since serum amyloid A did not affect body temperature or hypothalamic PGE2 levels when administered alone, it may represent a specific servo-mechanism for fever regulation in acute events, and it suggests, for the first time, a possible feedback relationship between serum amyloid A and the immunoregulatory cytokines.
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Abstract
The release of prostaglandin E (PGE) and prostacyclin (as 6-keto PGF1 alpha) by human osteomyelitic bone, compared with normal (control) bone, incubated in vitro was evaluated. Prostacyclin was the main arachidonic acid metabolite released by normal human bone, and similar quantities were released by osteomyelitic bone. However, PGE production was 5-30-fold higher in osteomyelitic bone, compared with control, thus becoming the major prostanoid in this disease. It is concluded that PGE production is probably involved in the inflammatory and/or bone resorption processes that occur in osteomyelitis.
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Affiliation(s)
- D Plotquin
- Department of Orthopedic Surgery, Soroka Medical Center, Beer-Sheva, Israel
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Affiliation(s)
- J W Smith
- Bronx Veteran's Administration Medical Center, New York
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Abstract
In a recent study, we found that lithium inhibits the function of guanine nucleotide-binding proteins, implicating G proteins as the common site for both the antimanic and antidepressant therapeutic effects of lithium. These findings may also suggest that an altered G protein function is of pathophysiological importance in bipolar affective disorder. In the present study, the coupling of both muscarinic-cholinergic receptors and beta-adrenergic receptors to pertussis toxin-sensitive G proteins or cholera toxin-sensitive G proteins was compared among untreated manic patients, lithium-treated euthymic bipolar patients, and healthy volunteers using mononuclear leukocyte (MNL) membrane preparations. Hyperactive function of G proteins was detected in untreated manic patients. Both isoproterenol-induced and carbamylcholine-induced increases in Gpp(NH)p binding capacity were twofold to threefold higher than the increases observed in healthy volunteers. On the other hand, lithium-treated euthymic bipolar patients showed G protein responses to agonist activation that were no different from the healthy volunteers. Altered G protein function may be of pathophysiological importance in bipolar affective disorder.
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Affiliation(s)
- G Schreiber
- Beer Sheva Mental Health Centre, Ida and Solomon Stern Psychiatry Research Unit, Ben Gurion University, Israel
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Kuipers EW, Vardi A, Danon A, Amirav A. Surface-molecule proton transfer: A demonstration of the Eley-Rideal mechanism. Phys Rev Lett 1991; 66:116-119. [PMID: 10043156 DOI: 10.1103/physrevlett.66.116] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Abstract
Recombinant interferon alpha-C (rIFN alpha-C, Interpharm), is a new type of alpha-interferon that has a specific activity of 1-2 x 10(9) units/mg protein. The pharmacokinetics of rIFN alpha-C were studied in 11 patients with metastatic renal-cell carcinoma. A total of 10 million units IFN alpha-C were injected intramuscularly and the serum level of IFN was evaluated up to 72 h post-administration. Measurable IFN concentrations appeared in the serum as early as 0.5 h, and levels peaked at 4-6 h (Cmax = 53.2 +/- 4.6 units/ml). Relatively high levels persisted for 24 h and declined thereafter with an apparent half-life of 3-4 h. The mean area under the serum-concentration curve (AUC) was 1,259 +/- 145 units h ml-1, indicating good bioavailability of the preparation from the intramuscular injection.
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Affiliation(s)
- O Merimsky
- Department of Oncology, Tel-Aviv Sourasky Medical Center, Israel
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