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Van Leugenhaege L, Van de Craen N, Maes K, Vanden Bergh L, Timmerman K, Van Aken S, Mestdagh E, Kuipers YJ. Virtual Reality as a Method to Cope With Labor Pain: What Do Women Want? Comput Inform Nurs 2024:00024665-990000000-00180. [PMID: 38701038 DOI: 10.1097/cin.0000000000001120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
This study aimed to determine what childbearing women want when using virtual reality as an intrapartum pain management method. Researchers performed a qualitative exploratory study using content analysis. Two focus groups were organized including pregnant women anticipating a vaginal birth and women who recently had given birth, no longer than 6 months ago. The focus groups included a 30-minute virtual reality demo. In total, 10 women participated. Five themes emerged: (1) "try, test and explore": the need to receive information and to get acquainted with virtual reality during the antenatal period; (2) "variety and diversity in physical and digital options": the preference for a variety in virtual content and view virtual reality as a complementary method to methods for intrapartum pain management; (3) "distraction versus focus": virtual reality as a method to distract from pain, from the clinical context or to help them focus; (4) "comfort both physical and digital": measures to ensure a comfortable physical and virtual experience; and (5) "birthing partner": the potential need to include partners. This study is an essential step informing the development, implementation, and research of labor-specific virtual reality and informing antenatal healthcare providers when offering women virtual reality as intrapartum pain management.
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Affiliation(s)
- Luka Van Leugenhaege
- Author Affiliations: Department of Health and Life Science, AP University of Applied Sciences and Arts, Antwerp (Mss Van Leugenhaege, Van de Craen, Maes, and Vanden Bergh and Drs Mestdagh and Kuipers); Centre for Research and Innovation in Care, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium MAXlab, Royal Academy of Fine Arts Antwerp, AP University of Applied Sciences and Arts (Mr Timmerman); and Immersive Lab, Department of Science and Technology, AP University of Applied Sciences and Arts (Dr Van Aken), Antwerp, Belgium; and School of Health and Social Care, Edinburgh Napier University, Scotland (Dr Kuipers)
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Beeckmans H, Kerckhof P, McDonough J, De Sadeleer L, Kaes J, Sacreas A, Aelbrecht C, Vanstapel A, Maes K, Schoemans H, Wauters E, Neyrinck A, Verleden G, Dupont L, Godinas L, Van Raemdonck D, Vanaudenaerde B, Vos R. Differences in the Transcriptional Landscape of Human End-Stage CLAD Phenotypes. J Heart Lung Transplant 2023. [DOI: 10.1016/j.healun.2023.02.123] [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: 04/05/2023] Open
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Miranda M, Leitão T, Maes K. Robot-assisted radical nephroureterectomy with extravesical excision of the intramural segment of the ureter. EUR UROL SUPPL 2021. [DOI: 10.1016/s2666-1683(21)02306-5] [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: 11/29/2022] Open
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Jeronimo Alves L, Maes K. Robotic partial nephrectomy and pyeloplasty for a cystic hilar tumor. EUR UROL SUPPL 2021. [DOI: 10.1016/s2666-1683(21)02294-1] [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] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Van Wanseele Y, Maes K, Lanckmans K, Van Schoors J, Smolders I, Van Eeckhaut A. Surface and Solvent Dependent Adsorption of Three Neuromedin-Like Peptides in Glass and Plastic Syringes. Chromatographia 2017. [DOI: 10.1007/s10337-017-3397-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Favreau M, Menu E, Gaublomme D, Vanderkerken K, Faict S, Maes K, De Bruyne E, Govindarajan S, Drennan M, Van Calenbergh S, Leleu X, Zabeau L, Tavernier J, Venken K, Elewaut D. Leptin receptor antagonism of iNKT cell function: a novel strategy to combat multiple myeloma. Leukemia 2017; 31:2678-2685. [PMID: 28490813 DOI: 10.1038/leu.2017.146] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/27/2017] [Accepted: 05/03/2017] [Indexed: 12/28/2022]
Abstract
A hallmark of bone marrow changes with aging is the increase in adipocyte composition, but how this impacts development of multiple myeloma (MM) is unknown. Here, we report the role of the adipokine leptin as master regulator of anti-myeloma tumor immunity by modulating the invariant natural killer T (iNKT) cell function. A marked increase in serum leptin levels and leptin receptor (LR) expression on iNKT cells in MM patients and the 5T33 murine MM model was observed. MM cells and leptin synergistically counteracted anti-tumor functionality of both murine and human iNKT cells. In vivo blockade of LR signaling combined with iNKT stimulation resulted in superior anti-tumor protection. This was linked to persistent IFN-γ secretion upon repeated iNKT cell stimulation and a restoration of the dynamic antigen-induced motility arrest as observed by intravital microscopy, thereby showing alleviation of iNKT cell anergy. Overall our data reveal the LR axis as novel therapeutic target for checkpoint inhibition to treat MM.
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Affiliation(s)
- M Favreau
- Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Rheumatology, Ghent University Hospital, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB Inflammation Research Center, Ghent University, Ghent, Belgium
| | - E Menu
- Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - D Gaublomme
- Department of Rheumatology, Ghent University Hospital, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB Inflammation Research Center, Ghent University, Ghent, Belgium
| | - K Vanderkerken
- Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - S Faict
- Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - K Maes
- Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - E De Bruyne
- Department of Hematology and Immunology, Myeloma Center Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - S Govindarajan
- Department of Rheumatology, Ghent University Hospital, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB Inflammation Research Center, Ghent University, Ghent, Belgium
| | - M Drennan
- Department of Rheumatology, Ghent University Hospital, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB Inflammation Research Center, Ghent University, Ghent, Belgium
| | - S Van Calenbergh
- Laboratory for Medicinal Chemistry, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - X Leleu
- Service d'Hématologie et Thérapie Cellulaire, Pôle Régional de Cancérologie, Hospital de la Miléterie, Poitiers, France
| | - L Zabeau
- Department of Biochemistry, VIB Medical Biotechnology Center, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - J Tavernier
- Department of Biochemistry, VIB Medical Biotechnology Center, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - K Venken
- Department of Rheumatology, Ghent University Hospital, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB Inflammation Research Center, Ghent University, Ghent, Belgium
| | - D Elewaut
- Department of Rheumatology, Ghent University Hospital, Ghent, Belgium.,Unit for Molecular Immunology and Inflammation, VIB Inflammation Research Center, Ghent University, Ghent, Belgium
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Bentea E, Van Liefferinge J, Verbruggen L, Martens K, Kobayashi S, Deneyer L, Demuyser T, Albertini G, Maes K, Sato H, Smolders I, Lewerenz J, Massie A. Zonisamide attenuates lactacystin-induced parkinsonism in mice without affecting system x c<sup/>. Exp Neurol 2016; 290:15-28. [PMID: 28024798 DOI: 10.1016/j.expneurol.2016.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 12/15/2016] [Accepted: 12/21/2016] [Indexed: 11/29/2022]
Abstract
Zonisamide (ZNS), an anticonvulsant drug exhibiting symptomatic effects in Parkinson's disease (PD), was recently reported to exert neuroprotection in rodent models. One of the proposed neuroprotective mechanisms involves increased protein expression of xCT, the specific subunit of the cystine/glutamate antiporter system xc-, inducing glutathione (GSH) synthesis. Here, we investigated the outcome of ZNS treatment in a mouse model of PD based on intranigral proteasome inhibition, and whether the observed effects would be mediated by system xc-. The proteasome inhibitor lactacystin (LAC) was administered intranigrally to male C57BL/6J mice receiving repeated intraperitoneal injections of either ZNS 30mgkg-1 or vehicle. Drug administration was initiated three days prior to stereotaxic LAC injection and was maintained until six days post-surgery. One week after lesion, mice were behaviorally assessed and investigated in terms of nigrostriatal neurodegeneration and molecular changes at the level of the basal ganglia, including expression levels of xCT. ZNS reduced the loss of nigral dopaminergic neurons following LAC injection and the degree of sensorimotor impairment. ZNS failed, however, to modulate xCT expression in basal ganglia of lesioned mice. In a separate set of experiments, the impact of ZNS treatment on system xc- was investigated in control conditions in vivo as well as in vitro. Similarly, ZNS did not influence xCT or glutathione levels in naive male C57BL/6J mice, nor did it alter system xc- activity or glutathione content in vitro. Taken together, these results demonstrate that ZNS treatment provides neuroprotection and behavioral improvement in a PD mouse model based on proteasome inhibition via system xc- independent mechanisms.
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Affiliation(s)
- Eduard Bentea
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Joeri Van Liefferinge
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lise Verbruggen
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Katleen Martens
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Sho Kobayashi
- Department of Food and Applied Life Sciences, Yamagata University, Yamagata, Japan
| | - Lauren Deneyer
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Thomas Demuyser
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Giulia Albertini
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Katrien Maes
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hideyo Sato
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Technology, Niigata University, Niigata, Japan
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Jan Lewerenz
- Department of Neurology, Ulm University, Ulm, Germany
| | - Ann Massie
- Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium.
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Van Schoors J, Maes K, Van Wanseele Y, Broeckhoven K, Van Eeckhaut A. Miniaturized ultra-high performance liquid chromatography coupled to electrochemical detection: Investigation of system performance for neurochemical analysis. J Chromatogr A 2016; 1427:69-78. [DOI: 10.1016/j.chroma.2015.11.076] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/19/2015] [Accepted: 11/24/2015] [Indexed: 01/03/2023]
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Walrave L, Maes K, Coppens J, Bentea E, Van Eeckhaut A, Massie A, Van Liefferinge J, Smolders I. Validation of the 6Hz refractory seizure mouse model for intracerebroventricularly administered compounds. Epilepsy Res 2015. [DOI: 10.1016/j.eplepsyres.2015.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Van Schoors J, Lens C, Maes K, Michotte Y, Smolders I, Van Eeckhaut A. Reassessment of the antioxidative mixture for the challenging electrochemical determination of dopamine, noradrenaline and serotonin in microdialysis samples. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 998-999:63-71. [DOI: 10.1016/j.jchromb.2015.06.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 05/18/2015] [Accepted: 06/12/2015] [Indexed: 10/23/2022]
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Maes K, Smolders I, Michotte Y, Van Eeckhaut A. Strategies to reduce aspecific adsorption of peptides and proteins in liquid chromatography-mass spectrometry based bioanalyses: an overview. J Chromatogr A 2014; 1358:1-13. [PMID: 25022477 DOI: 10.1016/j.chroma.2014.06.072] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 06/11/2014] [Accepted: 06/22/2014] [Indexed: 12/20/2022]
Abstract
In the drug-discovery setting, the development of new peptide and protein-based biopharmaceuticals attracts increased attention from the pharmaceutical industry and consequently demands the development of high-throughput LC-MS methods. Regulatory guidelines require bioanalytical methods to be validated not only in terms of linearity, sensitivity, accuracy, precision, selectivity and stability, but also in terms of carryover. Carryover results from the aspecific adsorption of analyte(s) to parts of the analytical system and thus introduces bias in both identification and quantification assays. Moreover, nonspecific binding occurs at the surface of materials used during sample preparation, such as pipette tips, sample tubes and LC-vials. Hence, linearity, sensitivity and repeatability of the analyses are negatively affected. Due to the great diversity in physicochemical properties of biomolecules, there is no general approach available to minimize adsorption phenomena. Therefore, we aim to present different strategies which can be generically applied to reduce nonspecific binding of peptides and proteins. In the first part of this review, a systematic approach is proposed to guide the reader through the different solvents which can be used to dissolve the analyte of interest. Indeed, proper solubilization is one of the most important factors for a successful analysis. In addition, alternative approaches are described to improve analyte recovery from the sample vial. The second part focuses on strategies to efficiently reduce adsorption at components of the autosampler, column and mass spectrometer. Thereby carryover is reduced while maintaining a sufficiently wide dynamic range of the assay.
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Affiliation(s)
- Katrien Maes
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Yvette Michotte
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Ann Van Eeckhaut
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
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Cheung K, Meulemans E, Wouters K, de Clercq M, Bartholomeeussen L, Sels M, Pallemans S, Wellens C, Ysebaert D, de Keersmaecker S, Verschueren C, de Clerck L, Baert D, Vandoninck C, Kindt S, Schelfaut S, Vankerkhove M, Troch A, Ceulemans L, Vandenbergh H, Leys S, Pauwels J, Rondou T, Dewitte E, Maes K, de Winter B, Vandewoude M, Van Gaal L, Van Aken P, Peeters M. Feasibility of cachexia screening in ambulatory cancer patients: A multicenter pilot study. NUTR CLIN METAB 2014. [DOI: 10.1016/j.nupar.2014.03.007] [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: 11/26/2022]
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Maes K, Agten A, Smuder A, Powers SK, Decramer M, Gayan-Ramirez G. Protective effect of methylprednisolone on ventilator-induced diaphragm dysfunction is dose dependent. Crit Care 2010. [PMCID: PMC2934408 DOI: 10.1186/cc8433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Agten A, Maes K, Smuder A, Powers SK, Decramer M, Gayan-Ramirez G. N-acetylcysteine attenuates ventilator-induced diaphragm dysfunction in rats. Crit Care 2010. [PMCID: PMC2934027 DOI: 10.1186/cc8435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Testelmans D, Crul T, Maes K, Agten A, Crombach M, Decramer M, Gayan-Ramirez G. Atrophy and hypertrophy signalling in the diaphragm of patients with COPD. Eur Respir J 2009; 35:549-56. [DOI: 10.1183/09031936.00091108] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Maes K. Thivolleo, a new genus with two new species from Africa (Lepidoptera: Pyraloidea, Crambidae, Pyraustinae). REV SUISSE ZOOL 2006. [DOI: 10.5962/bhl.part.80370] [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: 11/15/2022]
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Maes K. A new species of Diathrausta Lederer, 1863 from Africa (Lepidoptera, Pyraloidea, Crambidae, Spilomelinae). REV SUISSE ZOOL 2006. [DOI: 10.5962/bhl.part.80351] [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: 11/15/2022]
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Maes K, Vercammen J, Pham-Tuan H, Sandra P, Debergh PC. Critical aspects for the reliable headspace analysis of plants cultivated in vitro. Phytochem Anal 2001; 12:153-158. [PMID: 11705019 DOI: 10.1002/pca.579] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Various factors controlling the recoveries of volatile organic compounds in vitro headspace analysis of tomato plants (Lycopersicon esculentum Mill. 'Moneymaker'), sampled using solid phase micro-extraction, were evaluated and optimised. The variations in composition of the headspaces were determined as a function of time, and following in vitro wounding of the plant.
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Affiliation(s)
- K Maes
- Department of Plant Production-Horticulture, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
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Maes K, Missiaen L, Parys JB, De Smet P, Sienaert I, Waelkens E, Callewaert G, De Smedt H. Mapping of the ATP-binding sites on inositol 1,4,5-trisphosphate receptor type 1 and type 3 homotetramers by controlled proteolysis and photoaffinity labeling. J Biol Chem 2001; 276:3492-7. [PMID: 11035010 DOI: 10.1074/jbc.m006082200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Submillimolar ATP concentrations strongly enhance the inositol 1,4,5-trisphosphate (IP(3))-induced Ca(2+) release, by binding specifically to ATP-binding sites on the IP(3) receptor (IP(3)R). To locate those ATP-binding sites on IP(3)R1 and IP(3)R3, both proteins were expressed in Sf9 insect cells and covalently labeled with 8-azido-[alpha-(32)P]ATP. IP(3)R1 and IP(3)R3 were then purified and subjected to a controlled proteolysis, and the labeled proteolytic fragments were identified by site-specific antibodies. Two fragments of IP(3)R1 were labeled, each containing one of the previously proposed ATP-binding sites with amino acid sequence GXGXXG (amino acids 1773-1780 and 2016-2021, respectively). In IP(3)R3, only one fragment was labeled. This fragment contained the GXGXXG sequence (amino acids 1920-1925), which is conserved in the three IP(3)R isoforms. The presence of multiple interaction sites for ATP was also evident from the IP(3)-induced Ca(2+) release in permeabilized A7r5 cells, which depended on ATP over a very broad concentration range from micromolar to millimolar.
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Affiliation(s)
- K Maes
- Laboratorium voor Fysiologie and the Laboratorium voor Biochemie, K.U. Leuven Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium.
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Maes K, Billiet I, Haerens M, Mattelaer J. Massive bilateral renal and perirenal hemorrhage due to polyarteritis nodosa: a life-threatening urologic condition. Eur Urol 2000; 38:349-51. [PMID: 10940712 DOI: 10.1159/000020305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- K Maes
- Department of Urology, CAZK Groeninghe Hospital, Kortrijk, Belgium
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Bultynck G, De Smet P, Weidema AF, Ver Heyen M, Maes K, Callewaert G, Missiaen L, Parys JB, De Smedt H. Effects of the immunosuppressant FK506 on intracellular Ca2+ release and Ca2+ accumulation mechanisms. J Physiol 2000; 525 Pt 3:681-93. [PMID: 10856121 PMCID: PMC2269973 DOI: 10.1111/j.1469-7793.2000.t01-1-00681.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The immunophilin FKBP12 associates with intracellular Ca2+ channels and this interaction can be disrupted by the immunosuppressant FK506. We have investigated the effect of FK506 on Ca2+ release and Ca2+ uptake in permeabilized cell types. Changes in medium free [Ca2+] were detected by the fluorescent Ca2+ indicator fluo-3 in digitonin-permeabilized SH-SY5Y human neuroblastoma cells, DT40 and R23-11 (i.e. triple inositol 1,4,5-trisphosphate (IP3) receptor knockout cells) chicken B lymphocytes and differentiated and undifferentiated BC3H1 skeletal muscle cells. 45Ca2+ fluxes were studied in saponin-permeabilized A7r5 rat smooth muscle cells. Addition of FK506 to permeabilized SH-SY5Y cells led to a sustained elevation of the medium [Ca2+] corresponding to approximately 30 % of the Ca2+ ionophore A23187-induced [Ca2+] rise. This rise in [Ca2+] was not dependent on mitochondrial activity. This FK506-induced [Ca2+] rise was related to the inhibition of the sarcoplasmic/endoplasmic reticulum Ca2+-Mg2+-ATPase (SERCA) Ca2+ pump. Oxalate-facilitated 45Ca2+ uptake in SH-SY5Y microsomes was inhibited by FK506 with an IC50 of 19 microM. The inhibition of the SERCA Ca2+ pump was not specific since several macrocyclic lactone compounds (ivermectin > FK506, ascomycin and rapamycin) were able to inhibit Ca2+ uptake activity. FK506 (10 microM) did not affect IP3-induced Ca2+ release in permeabilized SH-SY5Y and A7r5 cells, but enhanced caffeine-induced Ca2+ release via the ryanodine receptor (RyR) in differentiated BC3H1 cells. In conclusion, FK506 inhibited active Ca2+ uptake by the SERCA Ca2+ pump; in addition, FK506 enhanced intracellular Ca2+ release through the RyR, but it had no direct effect on IP3-induced Ca2+ release.
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MESH Headings
- Animals
- Antiprotozoal Agents/pharmacology
- Aorta/cytology
- B-Lymphocytes/cytology
- Biological Transport/drug effects
- Biological Transport/physiology
- Caffeine/pharmacology
- Calcimycin/pharmacology
- Calcium/pharmacokinetics
- Calcium Channels/physiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Calcium-Transporting ATPases/metabolism
- Chickens
- Enzyme Inhibitors/pharmacology
- Humans
- Immunosuppressive Agents/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Ionophores/pharmacology
- Ivermectin/pharmacology
- Mice
- Microsomes/chemistry
- Microsomes/enzymology
- Muscle, Smooth, Vascular/chemistry
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/enzymology
- Neuroblastoma
- Oxalates/pharmacology
- Phosphodiesterase Inhibitors/pharmacology
- Rats
- Receptors, Cytoplasmic and Nuclear/physiology
- Sirolimus/pharmacology
- Spermine/pharmacology
- Tacrolimus/analogs & derivatives
- Tacrolimus/pharmacology
- Thapsigargin/pharmacology
- Tumor Cells, Cultured
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Affiliation(s)
- G Bultynck
- Laboratorium voor Fysiologie, K.U.Leuven Campus Gasthuisberg O/N, B-3000 Leuven, Belgium.
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22
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Maes K, Missiaen L, De Smet P, Vanlingen S, Callewaert G, Parys JB, De Smedt H. Differential modulation of inositol 1,4,5-trisphosphate receptor type 1 and type 3 by ATP. Cell Calcium 2000; 27:257-67. [PMID: 10859592 DOI: 10.1054/ceca.2000.0121] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [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: 11/18/2022]
Abstract
Binding of ATP to the inositol 1,4,5-trisphosphate receptor (IP(3)R) results in a more pronounced Ca(2+)release in the presence of inositol 1,4,5-trisphosphate (IP(3)). Two recently published studies demonstrated a different ATP sensitivity of IP(3)-induced Ca(2+)release in cell types expressing different IP(3)R isoforms. Cell types expressing mainly IP(3)R3 were less sensitive to ATP than cell types expressing mainly IP(3)R1 (Missiaen L, Parys JB, Sienaert I et al. Functional properties of the type 3 InsP(3)receptor in 16HBE14o- bronchial mucosal cells. J Biol Chem 1998;273: 8983-8986; Miyakawa T, Maeda A, Yamazawa T et al. Encoding of Ca(2+)signals by differential expression of IP(3)receptor subtypes. EMBO J 1999;18: 1303-1308). In order to investigate the difference in ATP sensitivity between IP(3)R isoforms at the molecular level, microsomes of Sf9 insect cells expressing full-size IP(3)R1 or IP(3)R3 were covalently labeled with ATP by using the photoaffinity label 8-azido[alpha-(32)P]ATP. ATP labeling of the IP(3)R was measured after immunoprecipitation of IP(3)Rs with isoform-specific antibodies, SDS-PAGE and Phosphorimaging. Unlabeled ATP inhibited covalent linking of 8-azido[alpha-(32)P]ATP to the recombinant IP(3)R1 and IP(3)R3 with an IC(50)of 1.6 microM and 177 microM, respectively. MgATP was as effective as ATP in displacing 8-azido[alpha-(32)P]ATP from the ATP-binding sites on IP(3)R1 and IP(3)R3, and in stimulating IP(3)-induced Ca(2+)release from permeabilized A7r5 and 16HBE14o- cells. The interaction of ATP with the ATP-binding sites on IP(3)R1 and IP(3)R3 was different from its interaction with the IP(3)-binding domains, since ATP inhibited IP(3)binding to the N-terminal 581 amino acids of IP(3)R1 and IP(3)R3 with an IC(50)of 353 microM and 4.0 mM, respectively. The ATP-binding sites of IP(3)R1 bound much better ATP than ADP, AMP and particularly GTP, while IP(3)R3 displayed a much broader nucleotide specificity. These results therefore provide molecular evidence for a differential regulation of IP(3)R1 and IP(3)R3 by ATP.
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Affiliation(s)
- K Maes
- Laboratorium voor Fysiologie, K U Leuven Campus Gasthuisberg, Herestraat 49, Leuven, B-3000,
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23
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van Acker K, Bautmans B, Bultynck G, Maes K, Weidema AF, de Smet P, Parys JB, de Smedt H, Missiaen L, Callewaert G. Mapping of IP(3)-mediated Ca(2+) signals in single human neuroblastoma SH-SY5Y cells: cell volume shaping the Ca(2+) signal. J Neurophysiol 2000; 83:1052-7. [PMID: 10669516 DOI: 10.1152/jn.2000.83.2.1052] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fast confocal laser-scanning microscopy was used to study spatiotemporal properties of IP(3)-mediated Ca(2+) release signals in human SH-SY5Y neuroblastoma cells. [Ca(2+)](i) increases were not affected by ryanodine (30 microgM) or caffeine (10 mM) and largely insensitive to removal of external Ca(2+), indicating predominance of IP(3)-induced Ca(2+) release. Ca(2+) signals evoked by high concentration (10 microM) of the muscarinic agonist carbachol appeared as self-propagating waves initiating in cell processes. At low carbachol concentrations (500 nM) Ca(2+) changes in most cells displayed striking spatiotemporal heterogeneity. The Ca(2+) response in the cell body was delayed and had a smaller amplitude and a slower rise time than that in processes. Ca(2+) changes in processes either occurred in a homogeneous manner throughout the whole process or were sometimes confined to hot spots. Regional differences in surface-to-volume ratio appear to be critical clues that determine the spatiotemporal pattern of intracellular Ca(2+) release signals.
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MESH Headings
- Caffeine/pharmacology
- Calcium/metabolism
- Calcium Channels/chemistry
- Calcium Channels/physiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Carbachol/pharmacology
- Cell Size/physiology
- Central Nervous System Stimulants/pharmacology
- Cholinergic Agonists/pharmacology
- Humans
- Image Processing, Computer-Assisted
- Inositol 1,4,5-Trisphosphate/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Microscopy, Confocal
- Microscopy, Fluorescence
- Neuroblastoma
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/physiology
- Tumor Cells, Cultured/chemistry
- Tumor Cells, Cultured/cytology
- Tumor Cells, Cultured/physiology
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Affiliation(s)
- K van Acker
- Laboratory of Physiology, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium
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24
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Maes K, Missiaen L, Parys JB, Sienaert I, Bultynck G, Zizi M, De Smet P, Casteels R, De Smedt H. Adenine-nucleotide binding sites on the inositol 1,4,5-trisphosphate receptor bind caffeine, but not adenophostin A or cyclic ADP-ribose. Cell Calcium 1999; 25:143-52. [PMID: 10326681 DOI: 10.1054/ceca.1998.0011] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [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: 11/18/2022]
Abstract
Binding of ATP to the inositol 1,4,5-trisphosphate receptor (IP3R) results in a more pronounced Ca2+ release in the presence of inositol 1,4,5-trisphosphate (IP3). We have expressed the cDNAs encoding two putative adenine-nucleotide binding sites of the neuronal form of IP3R-1 as glutathione S-transferase (GST)-fusion proteins in bacteria. Specific [alpha-32P]ATP binding was observed for the two GST-fusion proteins, representing aa 1710-1850 and aa 1944-2040 of IP3R-1. The ATP-binding sites in both fusion proteins had the same nucleotide specificity as found for the intact IP3R (ATP > ADP > AMP > GTP). Smaller GST-fusion proteins (aa 1745-1792 and aa 2005-2023) displayed a much weaker ATP-binding activity. CoA, which also potentiated IP3-induced Ca2+ release in A7r5 cells, interacted with the ATP-binding sites on the fusion proteins. Such interaction was not observed for 1,N6-etheno CoA and 3'-dephospho-CoA, which are much less effective in potentiating IP3-induced Ca2+ release. Since the adenine-containing compounds adenophostin A, caffeine and cyclic ADP-ribose modulate IP3-induced Ca2+ release, a possible effect of these compounds on the ATP-binding sites was examined. ATP stimulated adenophostin A- and IP3-induced Ca2+ release in A7r5 cells with an EC50 of respectively 21 and 20 microM. Also the threshold concentration of ATP for stimulating the release was similar for the two agonists. Adenophostin A (100 microM) and cyclic ADP-ribose (100 microM) were ineffective in displacing [alpha-32P]ATP from the binding sites of both GST-fusion proteins. Caffeine (50 mM), however, inhibited [alpha-32P]ATP binding to both fusion proteins by more than 50%. These data provide evidence for a direct interaction of caffeine but not of adenophostin A or cyclic ADP-ribose with the adenine-nucleotide binding sites of the IP3R.
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Affiliation(s)
- K Maes
- Laboratorium voor Fysiologie, K. U. Leuven Campus Gasthuisberg, Belgium.
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25
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Maes K, Goethuys H, Baert L. A cystine lower pole renal calculus treated with holmium: YAG laser using a flexible 9,5F transurethral ureteroscope. Acta Urol Belg 1998; 66:29-32. [PMID: 9864876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
We report a case of a 1.5 cm cystine staghorn calculus of the right lower pole in a 32 year female known cystinuric patient. With a 200 microns Holmium laser probe through a 9,5 F flexible ureteroscope the calculus was fragmented in small particles. An internal ureteral stent was inserted at the end of the procedure. All but one small residual fragments were evacuated spontaneously after removal of the stent. This case shows that flexible ureteroscopy combined with the Holmium laser is a safe and efficient procedure to treat medium size renal cystine calculi. It can be repeated in case of recurrence with minimal trauma to the urologic tract.
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Affiliation(s)
- K Maes
- Department of Urology, University Hospital Gasthuisberg-Leuven, Belgium
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26
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Missiaen L, Parys JB, Sienaert I, Maes K, Kunzelmann K, Takahashi M, Tanzawa K, De Smedt H. Functional properties of the type-3 InsP3 receptor in 16HBE14o- bronchial mucosal cells. J Biol Chem 1998; 273:8983-6. [PMID: 9535884 DOI: 10.1074/jbc.273.15.8983] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [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
The type-3 inositol 1,4,5-trisphosphate (InsP3) receptor is the major isoform expressed in 16HBE14o- cells from bronchial mucosa, representing 93% at the mRNA level as determined by ratio reverse transcription-polymerase chain reaction and about 81% at the protein level as determined with isoform-specific antibodies (Sienaert, I., Huyghe, S., Parys, J. B., Malfait, M., Kunzelmann, K., De Smedt, H., Verleden, G. M., and Missiaen, L., Pflügers Arch. Eur. Y. Physiol., in press). The present 45Ca2+ efflux experiments indicate that these InsP3 receptors were 3 times less sensitive to InsP3 and 11 times less sensitive to ATP than those in A7r5 cells, where the type-1 InsP3 receptor is the main isoform. ATP did not increase the cooperativity of the InsP3-induced Ca2+ release in 16HBE14o- cells, in contrast to its effect in A7r5 cells. The sulfhydryl reagent thimerosal also did not stimulate InsP3-induced Ca2+ release in 16HBE14o- cells, again in contrast to its effect in A7r5 cells. Adenophostin A was more potent than InsP3 in stimulating the release in both cell types. The biphasic activation of the InsP3 receptor by cytosolic Ca2+ occurred in both cell types. We conclude that Ca2+ release mediated by the type-3 InsP3 receptor mainly differs from that mediated by the type-1 InsP3 receptor by its lack of stimulation by sulfhydryl oxidation and its lower ATP and InsP3 sensitivity. The predominant expression of the type-3 InsP3 receptor in the bronchial mucosa may be part of a mechanism coping with oxidative stress in that tissue.
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Affiliation(s)
- L Missiaen
- Laboratorium voor Fysiologie, K. U. Leuven Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium.
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27
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Missiaen L, Parys JB, De Smedt H, Sienaert I, Sipma H, Vanlingen S, Maes K, Kunzelmann K, Casteels R. Inhibition of inositol trisphosphate-induced calcium release by cyclic ADP-ribose in A7r5 smooth-muscle cells and in 16HBE14o- bronchial mucosal cells. Biochem J 1998; 329 ( Pt 3):489-95. [PMID: 9445374 PMCID: PMC1219068 DOI: 10.1042/bj3290489] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ca2+ release from intracellular stores occurs via two families of intracellular channels, each with their own specific agonist: Ins(1, 4,5)P3 for the Ins(1,4,5)P3 receptor and cyclic ADP-ribose (cADPR) for the ryanodine receptor. We now report that cADPR inhibited Ins(1, 4,5)P3-induced Ca2+ release in permeabilized A7r5 cells with an IC50 of 20 microM, and in permeabilized 16HBE14o- bronchial mucosal cells with an IC50 of 35 microM. This inhibition was accompanied by an increase in specific [3H]Ins(1,4,5)P3 binding. 8-Amino-cADPR, but not 8-bromo-cADPR, antagonized this effect of cADPR. The inhibition was prevented by a whole series of inositol phosphates (10 microM) that did not affect Ins(1,4,5)P3-induced Ca2+ release, and by micromolar concentrations of PPi and various nucleotide di- or triphosphates. We propose that cADPR must interact with a novel regulatory site on the Ins(1,4,5)P3 receptor or on an associated protein. This site is neither the Ins(1,4,5)P3-binding domain, which prefers Ins(1,4,5)P3 and only binds nucleotides and PPi in the millimolar range, nor the stimulatory adenine nucleotide binding site.
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MESH Headings
- Adenine Nucleotides/metabolism
- Adenosine Diphosphate Ribose/analogs & derivatives
- Adenosine Diphosphate Ribose/metabolism
- Adenosine Diphosphate Ribose/physiology
- Animals
- Aorta
- Binding Sites
- Bronchi/cytology
- Bronchi/drug effects
- Bronchi/metabolism
- Caffeine/metabolism
- Calcium/antagonists & inhibitors
- Calcium/metabolism
- Calcium Channels/metabolism
- Cell Line
- Cyclic ADP-Ribose
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Humans
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Mucous Membrane/cytology
- Mucous Membrane/drug effects
- Mucous Membrane/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Rats
- Receptors, Cytoplasmic and Nuclear/metabolism
- Ryanodine Receptor Calcium Release Channel/metabolism
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Affiliation(s)
- L Missiaen
- Laboratorium voor Fysiologie, K.U. Leuven Campus Gasthuisberg, Belgium
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28
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Missiaen L, De Smedt H, Parys JB, Sipma H, Maes K, Vanlingen S, Sienaert I, Van Driessche W, Casteels R. Synergism between hypotonically induced calcium release and fatty acyl-CoA esters induced calcium release from intracellular stores. Cell Calcium 1997; 22:151-6. [PMID: 9330785 DOI: 10.1016/s0143-4160(97)90008-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [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: 02/05/2023]
Abstract
The non-mitochondrial Ca2+ stores in permeabilized A7r5 cells responded to a decrease in Mg-ATP concentration with a pronounced Ca2+ release if 20 microM CoA was present. This release was rather specific for the preincubation or removal of ATP. ATP gamma S was much less effective and AMP-PNP, GTP, ITP, CTP, UTP, ADP, AMP, adenosine and adenine had no effect. CoA activated with an EC50 of 6 microM. Dephospho-CoA was a less effective cofactor and desulfo-CoA was ineffective. The release induced by Mg-ATP removal did not occur in the presence of 2% fatty acid-free bovine serum albumin and did not develop at 4 degrees C. All these findings suggest that CoA had to be acylated by endogenous fatty-acyl-CoA synthetase to become effective. Myristoyl- and palmitoyl-CoA esters were identified as the most effective cofactors for the release. Ca2+ release induced by removing Mg-ATP did not occur if the osmolality of the medium was kept constant by addition of mannitol, sucrose, KCl, MgCl2 or Mg-GTP, indicating that the decrease in tonicity was the trigger for the release. Mg-ATP plus CoA also synergized with Ca2+ release induced by a hypotonic shock imposed by diluting the medium with H2O. Osmolality changes induced by decreasing the Mg-ATP concentration were more effective in releasing Ca2+ than equal decreases in concentration of all solutes. We conclude that fatty acyl-CoA esters sensitize the hypotonically induced Ca2+ release from the non-mitochondrial Ca2+ stores.
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Affiliation(s)
- L Missiaen
- Laboratorium voor Fysiologie, KU Leuven Campus Gasthuisberg, Belgium.
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29
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Missiaen L, Parys JB, Smedt HD, Sienaert I, Sipma H, Vanlingen S, Maes K, Casteels R. Effect of adenine nucleotides on myo-inositol-1,4,5-trisphosphate-induced calcium release. Biochem J 1997; 325 ( Pt 3):661-6. [PMID: 9271086 PMCID: PMC1218609 DOI: 10.1042/bj3250661] [Citation(s) in RCA: 27] [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] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of a whole series of adenine nucleotides on Ins(1,4,5)P3-induced Ca2+ release were characterized in permeabilized A7r5 smooth-muscle cells. Several adenine nucleotides activated the Ins(1, 4,5)P3 receptor. It was observed that 3'-phosphoadenosine 5'-phosphoulphate, CoA, di(adenosine-5')tetraphosphate (Ap4A) and di(adenosine-5')pentaphosphate (Ap5A) were more effective than ATP. Ap4A and Ap5A also interacted with a lower EC50 than ATP. In order to find out how these adenine nucleotides affected Ins(1,4, 5)P3-induced Ca2+ release, we have measured their effect on the response of permeabilized A7r5 cells to a progressively increasing Ins(1,4,5)P3 concentration. Stimulatory ATP and Ap5A concentrations had no effect on the threshold Ins(1,4,5)P3 concentration for initiating Ca2+ release, but they stimulated Ca2+ release in the presence of supra-threshold Ins(1,4,5)P3 concentrations by increasing the co-operativity of the release process. Inhibition of the Ins(1,4,5)P3-induced Ca2+ release at higher ATP concentrations was associated with a further increase in co-operativity and also with a shift in threshold towards higher Ins(1,4,5)P3 concentrations. ATP had no effect on the non-specific Ca2+ leak in the absence of Ins(1,4,5)P3. We conclude that the adenine-nucleotide-binding site can be activated by many different adenine nucleotides. Binding of these compounds to the transducing domain of the Ins(1,4,5)P3 receptor increases the efficiency of transmitting Ins(1,4,5)P3 binding to channel opening. The inhibition by high ATP concentrations is exerted at a different site, related to Ins(1,4,5)P3 binding.
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Affiliation(s)
- L Missiaen
- Laboratorium voor Fysiologie, K.U. Leuven Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium
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30
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Schelles W, De Gendt S, Maes K, Van Grieken RV. The use of a secondary cathode to analyse solid non-conducting samples with direct current glow discharge mass spectrometry: potential and restrictions. ACTA ACUST UNITED AC 1996; 355:858-60. [PMID: 15045279 DOI: 10.1007/s0021663550858] [Citation(s) in RCA: 14] [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] [Received: 12/06/1995] [Accepted: 12/16/1995] [Indexed: 10/26/2022]
Abstract
A direct current glow discharge mass spectrometer has been used to analyse solid non-conducting samples: glass, polycarbonate, marble, aluminium oxide and Teflon. This is made possible by the use of a so-called secondary cathode. The methodology of this concept is investigated and analytical figures of merit are presented.
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Affiliation(s)
- W Schelles
- Department of Chemistry, University of Antwerp (UIA), Universiteitsplein 1, B-2610, Antwerpen, Belgium
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31
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Medoff RJ, Maes K. A new device for the fixation of unstable pertrochanteric fractures of the hip. J Bone Joint Surg Am 1991; 73:1192-9. [PMID: 1890120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A new type of fixation device for the treatment of pertrochanteric fractures of the hip is described. The device has an axial-compression screw to allow compression along an axis parallel to the femoral shaft. As the fracture settles postoperatively, dynamic axial compression continues. This axial-compression device was used in twenty-five patients who had an unstable intertrochanteric or proximal subtrochanteric fracture of the proximal part of the femur. The average extent of axial impaction or settling was five millimeters (standard deviation, 1.3 millimeters) at the most recent follow-up examination, and the relationship between the femoral head and shaft was altered less than with the use of a conventional compression screw-plate device. A larger proportion of the patients who had the new device were able to walk fifteen meters (fifty feet) independently by the time of discharge from the hospital, even though they left the hospital earlier. No technical failures were seen in the patients who were treated with the axial-compression screw device. We believe that the axial-compression screw-plate device is appropriate for the treatment of unstable pertrochanteric fractures of the hip.
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Affiliation(s)
- R J Medoff
- Straub Clinic and Hospital, Honolulu, Hawaii
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