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Gunes A, Schmitt C, Bilodeau L, Huet C, Belblidia A, Baldwin C, Giard JM, Biertho L, Lafortune A, Couture CY, Cheung A, Nguyen BN, Galun E, Bémeur C, Bilodeau M, Laplante M, Tang A, Faraj M, Estall JL. IL-6 Trans-Signaling Is Increased in Diabetes, Impacted by Glucolipotoxicity, and Associated With Liver Stiffness and Fibrosis in Fatty Liver Disease. Diabetes 2023; 72:1820-1834. [PMID: 37757741 PMCID: PMC10658070 DOI: 10.2337/db23-0171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 08/31/2023] [Indexed: 09/29/2023]
Abstract
Many people living with diabetes also have nonalcoholic fatty liver disease (NAFLD). Interleukin-6 (IL-6) is involved in both diseases, interacting with both membrane-bound (classical) and circulating (trans-signaling) soluble receptors. We investigated whether secretion of IL-6 trans-signaling coreceptors are altered in NAFLD by diabetes and whether this might associate with the severity of fatty liver disease. Secretion patterns were investigated with use of human hepatocyte, stellate, and monocyte cell lines. Associations with liver pathology were investigated in two patient cohorts: 1) biopsy-confirmed steatohepatitis and 2) class 3 obesity. We found that exposure of stellate cells to high glucose and palmitate increased IL-6 and soluble gp130 (sgp130) secretion. In line with this, plasma sgp130 in both patient cohorts positively correlated with HbA1c, and subjects with diabetes had higher circulating levels of IL-6 and trans-signaling coreceptors. Plasma sgp130 strongly correlated with liver stiffness and was significantly increased in subjects with F4 fibrosis stage. Monocyte activation was associated with reduced sIL-6R secretion. These data suggest that hyperglycemia and hyperlipidemia can directly impact IL-6 trans-signaling and that this may be linked to enhanced severity of NAFLD in patients with concomitant diabetes. ARTICLE HIGHLIGHTS IL-6 and its circulating coreceptor sgp130 are increased in people with fatty liver disease and steatohepatitis. High glucose and lipids stimulated IL-6 and sgp130 secretion from hepatic stellate cells. sgp130 levels correlated with HbA1c, and diabetes concurrent with steatohepatitis further increased circulating levels of all IL-6 trans-signaling mediators. Circulating sgp130 positively correlated with liver stiffness and hepatic fibrosis. Metabolic stress to liver associated with fatty liver disease might shift the balance of IL-6 classical versus trans-signaling, promoting liver fibrosis that is accelerated by diabetes.
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Affiliation(s)
- Aysim Gunes
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
- Montreal Diabetes Research Centre, Montreal, Quebec, Canada
| | - Clémence Schmitt
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Programmes de biologie moléculaire, Faculté de médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Laurent Bilodeau
- Département de radiologie, Centre hospitalier de l’Université de Montréal (CHUM), Montreal, Quebec, Canada
| | - Catherine Huet
- Département de radiologie, Centre hospitalier de l’Université de Montréal (CHUM), Montreal, Quebec, Canada
| | - Assia Belblidia
- Département de radiologie, Centre hospitalier de l’Université de Montréal (CHUM), Montreal, Quebec, Canada
| | - Cindy Baldwin
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
| | - Jeanne-Marie Giard
- Liver Unit, Centre hospitalier de l’Université de Montréal (CHUM), Département de médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Laurent Biertho
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, Canada
- Département de chirurgie, Faculté de médecine, Université Laval, Quebec City, Quebec, Canada
| | - Annie Lafortune
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, Canada
- Département de chirurgie, Faculté de médecine, Université Laval, Quebec City, Quebec, Canada
| | - Christian Yves Couture
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, Canada
- Département de biologie moléculaire, biochimie médicale et pathologie, Université Laval, Quebec City, Quebec, Canada
| | - Angela Cheung
- Gastroenterology and Hepatology, Department of Medicine, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Bich N. Nguyen
- Département de pathologie et biologie cellulaire, Université de Montréal, Montreal, Quebec, Canada
| | - Eithan Galun
- Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Hospital, Jerusalem, Israel
| | - Chantal Bémeur
- Département de nutrition, Université de Montréal, Montreal, Quebec, Canada
- Labo HépatoNeuro, Centre de recherche du CHUM, Montreal, Quebec, Canada
| | - Marc Bilodeau
- Liver Unit, Centre hospitalier de l’Université de Montréal (CHUM), Département de médecine, Université de Montréal, Montreal, Quebec, Canada
| | - Mathieu Laplante
- Montreal Diabetes Research Centre, Montreal, Quebec, Canada
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Quebec City, Quebec, Canada
| | - An Tang
- Département de radiologie, Centre hospitalier de l’Université de Montréal (CHUM), Montreal, Quebec, Canada
| | - May Faraj
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
- Montreal Diabetes Research Centre, Montreal, Quebec, Canada
- Département de nutrition, Université de Montréal, Montreal, Quebec, Canada
| | - Jennifer L. Estall
- Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
- Montreal Diabetes Research Centre, Montreal, Quebec, Canada
- Programmes de biologie moléculaire, Faculté de médecine, Université de Montréal, Montreal, Quebec, Canada
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Veit G, Roldan A, Vaccarin C, Vadeboncoeur N, Bilodeau L, Matouk E, Lukacs G. 625: Optimized modulator combinations for rare CFTR mutants with good responsiveness to single correctors. J Cyst Fibros 2021. [DOI: 10.1016/s1569-1993(21)02048-8] [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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Mansour R, Thibodeau Antonacci A, Bilodeau L, Vazquez Romaguera L, Cerny M, Huet C, Gilbert G, Tang A, Kadoury S. Impact of temporal resolution and motion correction for dynamic contrast-enhanced MRI of the liver using an accelerated golden-angle radial sequence. Phys Med Biol 2020; 65:085004. [PMID: 32084661 DOI: 10.1088/1361-6560/ab78be] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This paper presents a prospective study evaluating the impact on image quality and quantitative dynamic contrast-enhanced (DCE)-MRI perfusion parameters when varying the number of respiratory motion states when using an eXtra-Dimensional Golden-Angle Radial Sparse Parallel (XD-GRASP) MRI sequence. DCE acquisition was performed using a 3D stack-of-stars gradient-echo golden-angle radial acquisition in free-breathing with 100 spokes per motion state and temporal resolution of 6 s/volume, and using a non-rigid motion compensation to align different motion states. Parametric analysis was conducted using a dual-input single-compartment model. Nonparametric analysis was performed on the time-intensity curves. A total of 22 hepatocellular carcinomas (size: 11-52 mm) were evaluated. XD-GRASP reconstructed with increasing number of spokes for each motion state increased the signal-to-noise ratio (SNR) (p < 0.05) but decreased temporal resolution (0.04 volume/s vs 0.17 volume/s for one motion state) (p < 0.05). A visual scoring by an experienced radiologist show no change between increasing number of motion states with same number of spokes using the Likert score. The normalized maximum intensity time ratio, peak enhancement ratio and tumor arterial fraction increased with decreasing number of motion states (p < 0.05) while the transfer constant from the portal venous plasma to the surrounding tissue significantly decreased (p < 0.05). These same perfusion parameters show a significant difference in case of tumor displacement more than 1 cm (p < 0.05) whereas in the opposite case there was no significant variation. While a higher number of motion states and higher number of spokes improves SNR, the resulting lower temporal resolution can influence quantitative parameters that capture rapid signal changes. Finally, fewer displacement compensation is advantageous with lower number of motion state due to the higher temporal resolution. XD-GRASP can be used to perform quantitative perfusion measures in the liver, but the number of motion states may significantly alter some quantitative parameters.
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Affiliation(s)
- Rihab Mansour
- Centre hospitalier de l'Université de Montréal (CHUM) Research center, Montréal, QC, Canada
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Lefebvre T, Petitclerc L, Hébert M, Bilodeau L, Sebastiani G, Olivié D, Gao ZH, Sylvestre MP, Cloutier G, Nguyen BN, Gilbert G, Tang A. MRI cine-tagging of cardiac-induced motion for noninvasive staging of liver fibrosis. J Magn Reson Imaging 2019; 51:1570-1580. [PMID: 31605412 DOI: 10.1002/jmri.26935] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 07/06/2019] [Accepted: 09/05/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND MR elastography is a noninvasive technique that provides high diagnostic accuracy for the staging of liver fibrosis; however, it requires external hardware and mainly assesses the right lobe. PURPOSE To evaluate the diagnostic performance of MRI cine-tagging for staging fibrosis in the left liver lobe, using biopsy as the reference standard. STUDY TYPE Institutional Review Board (IRB)-approved two-center prospective study. POPULATION Seventy-six patients with chronic liver disease who underwent an MRI cine-tagging examination and a liver biopsy within a 6-week interval. FIELD STRENGTH/SEQUENCE 2D-GRE multislice sequence at 3.0T with spatial modulation of the magnetization preparation sequence and peripheral pulse-wave triggering on two coronal slices chosen underneath the heart apex to capture maximal deformation with consecutive breath-holds adapted to patient cardiac frequency. ASSESSMENT A region of interest was selected in the liver close to the heart apex. Maximal strain was evaluated with the harmonic phase (HARP) technique. STATISTICAL TESTS Spearman's correlation, Kruskal-Wallis test, Mann-Whitney U-test, and receiver operating characteristic (ROC) analysis were performed. RESULTS Liver strain measured on tagged images decreased with higher histological fibrosis stage (ρ = -0.68, P < 0.0001). Strain values were significantly different between all fibrosis stages (P < 0.0001), and between groups of fibrosis stages ≤F3 vs. F4 (P < 0.05). Areas under the ROC curves were 0.95 (95% confidence interval: 0.89-1.00) to distinguish fibrosis stages F0 vs. F4, 0.81 (0.70-0.92) for stages F0 vs. ≥F1, 0.84 (0.76-0.93) for stages ≤F1 vs. ≥F2, 0.86 (0.78-0.94) for stages ≤F2 vs. ≥F3, and 0.87 (0.77-0.96) for stages ≤F3 vs. F4. DATA CONCLUSION MRI cine-tagging is a promising technique for measuring liver strain without additional elastography hardware. It could be used to assess the left liver lobe as a complement to current techniques assessing the right lobe. LEVEL OF EVIDENCE 1 Technical Efficacy: 3 J. Magn. Reson. Imaging 2020;51:1570-1580.
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Affiliation(s)
- Thierry Lefebvre
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,Medical Physics Unit, McGill University, Montréal, Québec, Canada
| | - Léonie Petitclerc
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Mélanie Hébert
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
| | - Laurent Bilodeau
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
| | - Giada Sebastiani
- Department of Medicine, Division of Gastroenterology and Hepatology, McGill University Health Centre (MUHC), Montréal, Québec, Canada
| | - Damien Olivié
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Zu-Hua Gao
- Department of Pathology, McGill University, Montréal, Québec, Canada
| | - Marie-Pierre Sylvestre
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,Department of Social and Preventive Medicine, École de santé publique de l'Université de Montréal (ESPUM), Montréal, Québec, Canada
| | - Guy Cloutier
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.,Institute of Biomedical Engineering, Université de Montréal, Montréal, Québec, Canada.,Laboratory of Biorheology and Medical Ultrasonics (LBUM), Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
| | - Bich N Nguyen
- Service of Pathology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada
| | - Guillaume Gilbert
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.,MR Clinical Science, Philips Healthcare Canada, Montréal, Québec, Canada
| | - An Tang
- Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,Institute of Biomedical Engineering, Université de Montréal, Montréal, Québec, Canada
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Thibodeau-Antonacci A, Petitclerc L, Gilbert G, Bilodeau L, Olivié D, Cerny M, Castel H, Turcotte S, Huet C, Perreault P, Soulez G, Chagnon M, Kadoury S, Tang A. Dynamic contrast-enhanced MRI to assess hepatocellular carcinoma response to Transarterial chemoembolization using LI-RADS criteria: A pilot study. Magn Reson Imaging 2019; 62:78-86. [PMID: 31247250 DOI: 10.1016/j.mri.2019.06.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/05/2019] [Accepted: 06/23/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE To identify quantitative dynamic contrast-enhanced (DCE)-MRI perfusion parameters indicating tumor response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE). MATERIALS AND METHODS This prospective pilot study was approved by our institutional review board; written and informed consent was obtained for each participant. Patients underwent DCE-MRI examinations before and after TACE. A variable flip-angle unenhanced 3D mDixon sequence was performed for T1 mapping. A dynamic 4D mDixon sequence was performed after contrast injection for assessing dynamic signal enhancement. Nonparametric analysis was conducted on the time-intensity curves. Parametric analysis was performed on the time-concentration curves using a dual-input single-compartment model. Treatment response according to Liver Reporting and Data System (LI-RADS) v2018 was used as the reference standard. The comparisons within groups (before vs. after treatment) and between groups (nonviable vs. equivocal or viable tumor) were performed using nonparametric bootstrap taking into account the clustering effect of lesions in patients. RESULTS Twenty-eight patients with 52 HCCs (size: 10-104 mm) were evaluated. For nonviable tumors (n = 27), time to peak increased from 62.5 ± 18.2 s before to 83.3 ± 12.8 s after treatment (P< 0.01). For equivocal or viable tumors (n = 25), time to peak and mean transit time significantly increased (from 54.4 ± 24.1 s to 69.5 ± 18.9 s, P < 0.01 and from 14.2 ± 11.8 s to 33.9 ± 36.8 s, P= 0.01, respectively) and the transfer constant from the extracellular and extravascular space to the central vein significantly decreased from 14.8 ± 14.1 to 8.1 ± 9.1 s-1 after treatment (P= 0.01). CONCLUSION This prospective pilot DCE-MRI study showed that time to peak significantly changed after TACE treatment for both groups (nonviable tumors and equivocal or viable tumors). In our cohort, several perfusion parameters may provide an objective marker for differentiation of treatment response after TACE in HCC patients.
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Affiliation(s)
- Alana Thibodeau-Antonacci
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada; Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Léonie Petitclerc
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada; Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | | | - Laurent Bilodeau
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada
| | - Damien Olivié
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada
| | - Milena Cerny
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada; Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Hélène Castel
- Department of Hepatology and Liver transplantation, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada
| | - Simon Turcotte
- Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada; Department of Surgery, Hepatopancreatobiliary and Liver Transplantation Service, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada
| | - Catherine Huet
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada
| | - Pierre Perreault
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada
| | - Gilles Soulez
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada
| | - Miguel Chagnon
- Department of Mathematics and Statistics, Université de Montréal, QC, Canada
| | - Samuel Kadoury
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada; Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada; École Polytechnique, Montréal, Québec, Canada
| | - An Tang
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada; Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.
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Lenglet A, Campeau MP, Mathieu D, Bahig H, Lambert L, Vu T, Roberge D, Bilodeau L, Filion E. Risk-adapted stereotactic ablative radiotherapy for central and ultra-central lung tumours. Radiother Oncol 2019; 134:178-184. [DOI: 10.1016/j.radonc.2019.01.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 12/25/2022]
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Mathieu D, Bilodeau L, Cousineau Daoust V, Filion É, Bedwani S, Lenglet A, Roberge D, Bahig H, Vu T, Côté N, Campeau M. Dosimetric Impacts of Variations in Organ at Risks Delineation during Lung Stereotactic Ablative Radiation Therapy. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.1524] [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: 10/28/2022]
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Mathieu D, Daoust VC, Bilodeau L, Bedwani S, Filion E, Lenglet A, Bahig H, Vu T, Roberge D, Campeau M. Central3D: A Clinical Tool for Robust Characterization of Centrally Located Non–small Cell Lung Cancer. Int J Radiat Oncol Biol Phys 2017. [DOI: 10.1016/j.ijrobp.2017.06.1748] [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]
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Coman I, Bilodeau L, Lavoie A, Carricart M, Tremblay F, Zlosnik JE, Berthiaume Y. Ralstonia mannitolilytica in cystic fibrosis: A new predictor of worse outcomes. Respir Med Case Rep 2016; 20:48-50. [PMID: 27995056 PMCID: PMC5153449 DOI: 10.1016/j.rmcr.2016.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 11/27/2016] [Accepted: 11/30/2016] [Indexed: 01/26/2023] Open
Abstract
Background Patients with Cystic Fibrosis are subject to repeated respiratory tract infections, with recent increasing isolation of unusual pathogens. Ralstonia species have lately been isolated at our institution, an organism historically frequently misidentified as Burkholderia or Pseudomonas. The prevalence of Ralstonia spp. in cystic fibrosis populations has yet to be determined, along with its clinical implications. Case presentations Seven patients out of the 301 followed at our cystic fibrosis clinic have had Ralstonia strains identified in their respiratory tract. Most strains identified were multi-drug resistant. After aquisition of Ralstonia spp., the patients' clinical course was characterized by more frequent and more severe respiratory infections along with prolonged hospitalizations, greater decline of lung function, and greater mortality. The mortality rate in this group of patients was 86%. No other factor that could explain such a dramatic evolution was identified upon review of patient data. Some of the strains involved were recognized as clones on Pulse Field Electrophoresis Gel, raising the question of person-to-person transmission. Conclusion New pathogens are identified with the evolution of the microbiota in cystic fibrosis respiratory tracts. In our cohort of patients, acquisition of Ralstonia spp. was associated with dramatic outcomes in terms of disease acceleration and raised mortality rates. It is of critical importance to continue to better define the prevalence and clinical impact of Ralstonia in cystic fibrosis populations.
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Affiliation(s)
- I Coman
- Centre hospitalier de l'Université de Montréal (CHUM Hôtel-Dieu), Respiratory Service, 3840 St Urbain St, Montreal, QC, H2W 1T8, Canada
| | - L Bilodeau
- Institut universitaire de cardiologie et de pneumologie de Québec (IUCPQ), 2725 Chemin Ste-Foy, Quebec, QC, G1V 4G5, Canada
| | - A Lavoie
- Centre hospitalier de l'Université de Montréal (CHUM Hôtel-Dieu), Respiratory Service, 3840 St Urbain St, Montreal, QC, H2W 1T8, Canada
| | - M Carricart
- Centre hospitalier de l'Université de Montréal (CHUM Hôtel-Dieu), Respiratory Service, 3840 St Urbain St, Montreal, QC, H2W 1T8, Canada
| | - F Tremblay
- Centre hospitalier de l'Université de Montréal (CHUM Hôtel-Dieu), Respiratory Service, 3840 St Urbain St, Montreal, QC, H2W 1T8, Canada
| | - J E Zlosnik
- University of British Columbia, 2329 West Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Y Berthiaume
- Centre hospitalier de l'Université de Montréal (CHUM Hôtel-Dieu), Respiratory Service, 3840 St Urbain St, Montreal, QC, H2W 1T8, Canada; Institut de recherches cliniques de Montréal (IRCM), 110 Pine Avenue Ouest, Montreal, QC, H2W 1R7, Canada
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Lambert L, Sas G, Dragieva N, Reeves F, Langlois Y, Nguyen M, Bilodeau L, Voisine P, Carrier M, Pellerin M, Morin J, Bogaty P. WHAT KINDS OF PATIENTS WITH CORONARY ARTERY DISEASE ARE TREATED WITH MULTIVESSEL PERCUTANEOUS INTERVENTION VERSUS BYPASS SURGERY? A PROVINCE-WIDE FIELD EVALUATION IN QUÉBEC HOSPITALS WITH ON-SITE CARDIAC SURGERY. Can J Cardiol 2014. [DOI: 10.1016/j.cjca.2014.07.452] [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: 10/24/2022] Open
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Mylotte D, Andalib A, Theriault-Lauzier P, Dorfmeister M, Girgis M, Alharbi W, Chetrit M, Galatas C, Mamane S, Sebag I, Buithieu J, Bilodeau L, de Varennes B, Lachapelle K, Lange R, Martucci G, Virmani R, Piazza N. Transcatheter heart valve failure: a systematic review. Eur Heart J 2014; 36:1306-27. [DOI: 10.1093/eurheartj/ehu388] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 08/28/2014] [Indexed: 11/14/2022] Open
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Trépanier C, Tabrizian M, Yahia LH, Bilodeau L, Piron DL. Improvement of the Corrosion Resistance of NiTi Stents by Surface Treatments. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-459-363] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTBecause of its optimal radiopacity, superelasticity and shape memory properties Nickel-Titanium (NiTi) is an ideal material for the fabrication of stents. Indeed, these properties can facilitate the implantation and precise positioning of those devices. However, in vitro studies on NiTi report the dependency of the alloy biocompatibility and corrosion behavior to surface treatments. Oxidation of the surface seems to be very promising to improve both the corrosion resistance and the biocompatibility of NiTi. The present study investigate the effect of electropolishing, heat treatment (in air and in a salt bath) and nitric acid passivation to modify the oxide layer on NiTi stents. Techniques such as potentiodynamic polarization tests, Scanning Electron Microscopy (SEM) and Auger Electron Spectroscopy (AES) have been used to develop relationships between corrosion behavior, surface characteristics and surface treatment. Results show that all surface treatments improve the corrosion behavior of the alloy. SEM results indicate that treated stents which exhibit a smooth and uniform surface show a higher corrosion resistance than non treated stents which possess a very porous oxide layer. AES results, indicate that the best corrosion behavior was observed for the stents which exhibit the thinnest oxide layer (electropolished and passivated samples).
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Bilodeau L, Cavanagh P. Disintegration of shapes in peripherally viewed rotating displays. J Vis 2010. [DOI: 10.1167/1.3.21] [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] Open
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14
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Sack S, Kahlert P, Bilodeau L, Pièrard L, Lancellotti P, Legrand V, Bartunek J, Vanderheyden M, Hoffmann R, Schauerte P, Shiota T, Marks D, Ellis S, Erbel R. Initial Experiences with a Non-Stented Coronary Sinus Device for the Treatment of Functional Mitral Regurgitation: Results of the PTOLEMY I Feasibility Trial. Heart Lung Circ 2010. [DOI: 10.1016/j.hlc.2010.06.986] [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]
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15
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Haeck JD, Kuijt WJ, Koch KT, Bilodeau L, Henriques JP, Rohling WJ, Baan J, Vis MM, Nijveldt R, van Geloven N, Groenink M, Piek JJ, Tijssen JG, Krucoff MW, De Winter RJ. Infarct size and left ventricular function in the PRoximal Embolic Protection in Acute myocardial infarction and Resolution of ST-segment Elevation (PREPARE) trial: ancillary cardiovascular magnetic resonance study. Heart 2009; 96:190-5. [PMID: 19858136 DOI: 10.1136/hrt.2009.180448] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVES The aim of the study was to evaluate whether primary percutaneous coronary intervention (PCI) with combined proximal embolic protection and thrombus aspiration results in smaller final infarct size and improved left ventricular function assessed by cardiovascular magnetic resonance (CMR) in ST-segment elevation myocardial infarction (STEMI) patients compared with primary PCI alone. Background Primary PCI with the Proxis system improves immediate microvascular flow post-procedure as measured by ST-segment resolution, which could result in better outcomes. METHODS The ancillary CMR study included 206 STEMI patients who were enrolled in the PRoximal Embolic Protection in Acute myocardial infarction and Resolution of ST-Elevation (PREPARE) trial. CMR imaging was assessed between 4 and 6 months after the index procedure. RESULTS There were no significant differences in final infarct size (6.1 g/m(2) vs 6.3 g/m(2), p = 0.78) and left ventricular ejection fraction (50% vs 50%, p = 0.46) between both groups. Also, systolic wall thickening in the infarct area (44% vs 45%, p = 0.93) or the extent of transmural segments (8.3% of segments vs 8.3% of segments, p = 0.60) showed no significant differences. The incidence of major adverse cardiac and cerebral events at 6 months was similar in the Proxis and control group (8% vs 10%, respectively, p = 0.43). Conclusions Primary PCI with combined proximal embolic protection and thrombus aspiration in STEMI patients did not result in significant differences in final infarct size or left ventricular function at follow-up CMR. In addition, there was no difference in the incidence of major adverse cardiac and cerebral events at 6 months. TRIAL REGISTRATION number ISRCTN71104460.
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Affiliation(s)
- J D Haeck
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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16
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Abstract
e20516 Background: An important objective of the patient self determination act is for patients to see their wishes fulfilled, particularly at the end of life. Studies by Tiernan et al have shown that up to 80% of patients prefer to die at home however only a small proportion of patients actually die at home. Our work on support care networks show that a large proportion of women with cancer rely on multiple persons for health care proxy roles and for primary support. Given this, we sought to determine whether conducting a formal family meeting predicts whether a patient's preferred place of death corresponds with their actual place of death. Methods: We conducted a retrospective review of 105 women seen at Women & Infants’ Hospital within the last 12 weeks of their death and stratified patients between those who had a documented family meeting and those who did not. Results: Seventy-two percent (n= 105) of the study sample had family meetings in the last 12 weeks of life. Of those who had family meetings, 61% of patients whose preference of place of death coincide with their actual place of death (p<0.0001). In the sample of patients whose wishes coincide with their family meetings (n=76), almost 60% died at home and 34% died at inpatient hospice. Of those who did not have family meetings, 89% had unknown preferences of place of death, 48% died at the nursing home, 24% died in the hospital and 24% died at home. These results reached statistical significance (p= 0.001). Conclusions: Women who had a family meeting within the last 12 weeks of life were significantly more likely to die at home or with hospice services as compared to those who did not. This highlights the importance of including a patient's support networks into any communication between those dying from cancer and their healthcare providers. A larger study is warranted to determine whether this experience is specific to women with terminal cancer or is applicable to all patients with cancer facing the end of life. No significant financial relationships to disclose.
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Affiliation(s)
- R. Shields
- Brown University/Rhode Island Hospital, Warwick, RI; Women and Infants Hospital, Providence, RI
| | - W. Young
- Brown University/Rhode Island Hospital, Warwick, RI; Women and Infants Hospital, Providence, RI
| | - L. Bilodeau
- Brown University/Rhode Island Hospital, Warwick, RI; Women and Infants Hospital, Providence, RI
| | - W. Bergren
- Brown University/Rhode Island Hospital, Warwick, RI; Women and Infants Hospital, Providence, RI
| | - D. Dizon
- Brown University/Rhode Island Hospital, Warwick, RI; Women and Infants Hospital, Providence, RI
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17
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Frangos C, Noble S, Noble J, Bilodeau L. [Chronic total occlusion: the last frontier of the interventional cardiology?]. Rev Med Suisse 2007; 3:1392-4, 1396-8. [PMID: 17645053] [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: 05/16/2023]
Abstract
Recanalization of chronic total occlusion remains a challenge for the interventional cardiologist and accounts for 10-20% of all angioplasty procedures in high-volume catheterization laboratories. During the last few years, development in guidewires and devices as well as the emergence of new techniques from japanese centers resulted in a higher success rates in experienced operator's hands. The impact of drug eluting stents on restenosis has improved longterm outcome after chronic total occlusion successfull recanalization. This procedure requires time, patience from the operator and does also expose the patient to increased radiation and contrast administrations. In symptomatic patients, when recanalization is successful, the clinical outcome and the event free survival are improved.
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Affiliation(s)
- C Frangos
- Institut de cardiologie de Montréal, 5000, rue Bélanger, Montreal.
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18
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Noble S, Bilodeau L. [Percutaneous therapies for aortic and mitral valvular disease]. Rev Med Suisse 2007; 3:1360-1, 1363-4, 1366-7. [PMID: 17645049] [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: 05/16/2023]
Abstract
For a few years, numerous articles and lectures were published as well as presented at major meetings on percutaneous therapies for valvular heart disease. Calcific aortic stenosis in the elderly is frequent and difficult to manage with 1/3 of patients not operated because of high surgical risks. In 2002, the first percutaneous aortic valve bioprosthesis was implanted. Since then, several hundreds of interventions were performed with 2 different valves (Cribier-Edwards, Corevalve). Preliminary results are encouraging. Regarding percutaneous mitral valve interventions, balloon valvuloplasty for stenosis is well established but treatment modalities for mitral insufficiency remain complex due to a wide disease spectrum. Therefore, development is more at a preliminary level and the window of application may be narrower, but still attractive.
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Affiliation(s)
- S Noble
- Institut de cardiologie de Montréal, 5000 Rue Bélanger, Montréal.
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19
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Perrault LP, Jeanmart H, Bilodeau L, Lespérance J, Tanguay JF, Bouchard D, Pagé P, Carrier M. Early quantitative coronary angiography of saphenous vein grafts for coronary artery bypass grafting harvested by means of open versus endoscopic saphenectomy: a prospective randomized trial. J Thorac Cardiovasc Surg 2004; 127:1402-7. [PMID: 15115999 DOI: 10.1016/j.jtcvs.2003.10.040] [Citation(s) in RCA: 46] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Endoscopic saphenectomy is associated with a decreased incidence of wound complications without an increase in histologic trauma or endothelial dysfunction in published reports. Concern remains about the patency of saphenous vein grafts harvested endoscopically and the development of early intimal hyperplasia. The purpose of this study was to compare early quantitative coronary analysis of saphenous vein grafts used for coronary artery bypass grafting harvested with the open versus endoscopic techniques. METHODS Forty patients undergoing primary coronary artery bypass grafting surgery with at least 1 saphenous vein graft were randomized preoperatively to open versus endoscopic saphenectomy with bipolar cauterization of side branches. Quantitative coronary angiography was performed a mean of 3 months (range, 1-9 months) after the operation. RESULTS There was no statistically significant difference in the patency rates of internal thoracic artery grafts between the open and endoscopic groups and no statistically significant difference in the patency rates of saphenous vein grafts between both groups (85.2% vs 84.4%, P =.991). Quantitative coronary angiography showed no difference in graft stenosis (>or=50% of the internal diameter of the graft) in the body of the saphenous vein grafts in the open versus endoscopic saphenectomy groups (3.7% vs 0%, P =.280). CONCLUSION Angiographic appearance and patency rates of saphenous vein grafts harvested with the endoscopic technique are similar to those of saphenous vein grafts harvested with the open technique. These results support the use of endoscopic saphenectomy because of the known lower incidence of wound and infectious complications and superior functional results.
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Affiliation(s)
- L P Perrault
- Research Center, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada.
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20
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Serruys PW, Grines CL, Stone GW, Garcia E, Kiemeney F, Morice MC, Sousa JE, Hamm C, Costantini C, Probst P, Rutsch W, Penn I, Fernandez-Aviles F, Vandormael M, Bartorelli A, Bilodeau L, Eijgelshoven MHJ. Stent implantation in acute myocardial infarction using a heparin-coated stent: a pilot study as a preamble to a randomized trial comparing balloon angioplasty and stenting. Int J Cardiovasc Intervent 2003; 1:19-27. [PMID: 12623410 DOI: 10.1080/acc.1.1.19.27] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Preliminary experience with primary stenting in myocardial infarction has suggested a greater benefit in clinical outcome than has been obtained with direct balloon angioplasty. However, subacute thrombosis (SAT) remains a limitation for this new mode of therapy. In the BENESTENT II Pilot and main trials, the incidence of SAT with the heparin-coated Palmaz-Schatz stent was only 0.15%. Therefore, as a preamble to a large randomized trial, the feasibility and safety of the use of the Heparin-Coated Palmaz-Schatz trade mark Stent in Acute Myocardial Infarction (AMI) was tested in 101 patients enrolled between April and September 1996 in 18 clinical centres. In 101 stent-eligible AMI patients, as dictated by protocol, a heparin-coated stent was implanted. The primary objectives were to determine the in-hospital incidence of major adverse cardiac events (MACE: death, MI, target lesion revascularization) and bleeding complications, while the secondary objectives were the procedural success rate and the MACE, the restenosis and reocclusion rates at 6.5 months. Stent implantation (n 3 129 stents) was successful in 97 patients of the 101 who were included in this trial. During their hospital stay, two patients died and no patient experienced re-infarction, ischaemia prompting re-PTCA or CABG. Four patients suffered a bleeding complication, three major and one minor, of whom three required surgical repair. At 210 days follow-up, 81% of the patients were event free. At 6.5 months restenosis was documented in 18% of the 88 patients who underwent follow-up angiography, including three total occlusions. The results, both with respect to QCA and the occurrence of MACE, compare favourably with studies using elective stenting in both stable and unstable angina patients. As a result of this pilot study, a large randomized trial comparing direct balloon angioplasty with direct stenting in 900 patients with AMI was initiated in December 1996.
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Affiliation(s)
- PW Serruys
- Department of Interventional Cardiology, Academic Hospital Dijkzigt, Rotterdam, The Netherlands
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21
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Thierry B, Merhi Y, Bilodeau L, Trépanier C, Tabrizian M. Nitinol versus stainless steel stents: acute thrombogenicity study in an ex vivo porcine model. Biomaterials 2002; 23:2997-3005. [PMID: 12069342 DOI: 10.1016/s0142-9612(02)00030-3] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.0] [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: 11/16/2022]
Abstract
Acute and subacute stents thrombosis along with thrombus mediating neointimal proliferation within the stent struts remain major concerns in coronary stenting. Up to date, there is an obvious lack of data on the thrombogenicity of stent materials in physiological conditions. This study was performed to compare the relative thrombogenicity of nitinol versus stainless steel stents. Nitinol stents were laser cut to reproduce the exact geometry of the stainless steel Palmaz stents and tested in an ex vivo AV shunt porcine model under controlled conditions. Nitinol stents presented only small amounts of white and/or red thrombus principally located at the strut intersections while Palmaz stents clearly exhibited more thrombus. As a result, 125I-fibrin(ogen) adsorption and (111)I-platelets adhesion were significantly lower on nitinol than on stainless steel devices (36%, p = 0.03 for fibrin(ogen) and 63%, p = 0.01 for platelet). These results were confirmed by scanning electron observations showing different thrombus morphologies for nitinol and stainless steel. Along with the unique mechanical properties of nitinol, its promising haemocompatibility demonstrated in our study may promote their increasing use for both peripheral and coronary revascularization procedures.
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Affiliation(s)
- B Thierry
- Department of Biomedical Engineering, McGill University, Montreal , QC, Canada
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22
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Doucet S, Schalij MJ, Vrolix MC, Hilton D, Chenu P, de Bruyne B, Udayachalerm W, Seth A, Bilodeau L, Reiber JH, Harel F, Lespérance J. Stent placement to prevent restenosis after angioplasty in small coronary arteries. Circulation 2001; 104:2029-33. [PMID: 11673341] [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: 02/22/2023]
Abstract
BACKGROUND Lesions in small-diameter vessels (<3 mm) define a group with distinct clinical and morphological characteristics. There is an inverse relationship between vessel size and angiographic restenosis rate. This study assessed whether stents reduce angiographic restenosis in small coronary arteries compared with standard balloon angioplasty. METHODS AND RESULTS We randomly assigned 351 symptomatic patients needing dilatation of 1 native coronary vessel between 2.3 and 2.9 mm in size to angioplasty alone (n=182) or stent implantation (n=169). The primary end point was angiographic restenosis at 6 months. Secondary end points included death, myocardial infarction, bypass surgery, and target vessel revascularization in hospital and at 6 months. There were no significant differences between groups in terms of major in-hospital complications. There was a trend toward fewer in-hospital events in the stent group (3% versus 7.1% in angioplasty group, P=0.076). Crossovers to stent occurred in 37 patients (20.3%). Repeat angiography at 6-month follow-up was performed in 85.3% of patients. Angiographic restenosis occurred in 28% of the stent group and 32.9% of the angioplasty group (P=0.36). Target vessel revascularization was required in 17.8% versus 20.3% of patients (P=0.54), respectively. CONCLUSIONS Stenting and standard coronary angioplasty are associated with equal restenosis rate in small coronary arteries. With a lower in-hospital complication rate, stenting may be a superior strategy in small vessels.
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Affiliation(s)
- S Doucet
- Department of Medicine, Montreal Heart Institute, Montreal, Quebec, Canada.
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23
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Chandrasekar B, Doucet S, Bilodeau L, Crepeau J, deGuise P, Gregoire J, Gallo R, Cote G, Bonan R, Joyal M, Gosselin G, Tanguay JF, Dyrda I, Bois M, Pasternac A. Complications of cardiac catheterization in the current era: a single-center experience. Catheter Cardiovasc Interv 2001; 52:289-95. [PMID: 11246238 DOI: 10.1002/ccd.1067] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [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: 11/06/2022]
Abstract
Consecutive cardiac catheterization procedures done over a 2-yr period (April 1996 to March 1998) were prospectively analyzed to determine and characterize procedure-related complications (in-hospital and 1-mo follow-up), as they occur at present. During the study period, 11,821 procedures (7,953 diagnostic and 3,868 therapeutic) were performed. The majority of procedures (> 60%) were done in high-risk patients. Stents were implanted in 33% of patients, and adjunctive abciximab was used in 6.6% of therapeutic procedures. The overall complication rate was 8% (3.6% of diagnostic procedures and 15.1% of therapeutic procedures). The procedure-related mortality rates were 0.2%, 0.1%, and 0.5% for total, diagnostic, and therapeutic procedures, respectively. Cardiac complications were seen in 3.9% (1.5% of diagnostic and 9% of therapeutic procedures). Emergency cardiac surgery was required in 0.05% of the diagnostic procedure group and 0.3% of the therapeutic procedure group (total, 0.1%). Despite marked changes in patient population and practice, the complication rates of cardiac catheterization remain very low.
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Affiliation(s)
- B Chandrasekar
- Cardiac Catheterization Laboratory, Department of Medecine, Montreal Heart Institute, Montreal, Québec, Canada
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24
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Ahn T, Shin E, Merhi Y, Thai P, Bilodeau L. Influence of stent expansion states on platelet deposition in an extracorporeal porcine arteriovenous shunt model using a multichannel perfusion chamber. J Korean Med Sci 2001; 16:31-8. [PMID: 11289398 PMCID: PMC3054568 DOI: 10.3346/jkms.2001.16.1.31] [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] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Limited data are available about incomplete stent expansion (SE) on platelet deposition (PD). We examined PD following different SE using an extracorporeal porcine arteriovenous shunt model to which a perfusion chamber with four parallel silastic tubes were connected. Blood flow was set at a 20 and 100 mL/min in 1.8 and 3.1 mm diameter tubes, respectively. P154 stents were deployed completely (Group A, n=15) or incompletely (Group B, n=15) in 1.8 mm (n=13) and 3.1 mm (n=17) tubes. 51Cr-labelled platelet autologous blood was injected 1 hr before the perfusion. After 15 min-perfusion, the testing tubes were assessed for radioactivity counts. In-stent cross sectional area was measured by intravascular ultrasound. There was a significant difference in PD between group A and B regardless of channel size (118+/-18.4 vs 261.4+/-52.1 pits x 10(6)/cm2, p<0.05). With adjusted shear rate and similar stenosis, PD was similar in both tubes. In smaller 1.8 mm tubes, a stenosis as subtle as 10% was associated with a significant PD difference (226.1+/-20 vs 112.9+/-20.5 plts x 10(6)/cm2, p<0.005). This model enabled a repetitive, simultaneous comparison of PD following different SE states. It seems that the quality of SE remains crucial in smaller channels.
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Affiliation(s)
- T Ahn
- Department of Internal Medicine, Gachon University Hospital, Inchon, Korea.
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25
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Faubert J, Bilodeau L, Simonet P. Transverse chromatic aberration and colour-defined motion. Ophthalmic Physiol Opt 2000; 20:274-80. [PMID: 10962692] [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] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
A number of recent studies have explored the role of the chromatic system in motion processes using the isoluminance paradigm. A major concern when using such methodological procedures is potential artefacts produced by chromatic aberrations. In the present study we address the problem of optically induced luminance artefacts produced by transverse chromatic aberrations (TCA), which may contaminate the results obtained in chromatic motion-nulling experiments. Results show that different TCA levels artificially increase chromatic motion sensitivity values to varying degrees above 0.5 cpd for red/green gratings. The data also suggest the notion that naturally occurring TCA can decrease motion-nulling thresholds for chromatic gratings at high spatial frequencies. Furthermore, our data show that the motion-nulling paradigm for chromatic gratings may in fact be an efficient functional method for assessing the amount of TCA produced by optical factors.
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Affiliation(s)
- J Faubert
- Ecole d'Optométrie, Université de Montréal, Canada.
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26
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Abstract
Because of its good radiopacity, superelasticity, and shape memory properties, nickel-titanium (NiTi) is a potential material for fabrication of stents because these properties can facilitate their implantation and precise positioning. However, in vitro studies of NiTi alloys report the dependence of alloy biocompatibility and corrosion behavior on surface conditions. Surface oxidation seems to be very promising for improving the corrosion resistance and biocompatibility of NiTi. In this work, we studied the effect on corrosion resistance and surface characteristics of electropolishing, heat treatment, and nitric acid passivation of NiTi stents. Characterization techniques such as potentiodynamic polarization tests, scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy were used to relate corrosion behavior to surface characteristics and surface treatments. Results show that all of these surface treatments improve the corrosion resistance of the alloy. This improvement is attributed to the plastically deformed native oxide layer removal and replacement by a newly grown, more uniform one. The uniformity of the oxide layer, rather than its thickness and composition, seems to be the predominant factor to explain the corrosion resistance improvement.
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Affiliation(s)
- C Trépanier
- GRBB, Biomedical Engineering Institute, Ecole Polytechnique de Montréal, Quebec, Canada
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27
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Trépanier C, Leung TK, Tabrizian M, Yahia LH, Bienvenu JG, Tanguay JF, Piron DL, Bilodeau L. Preliminary investigation of the effects of surface treatments on biological response to shape memory NiTi stents. J Biomed Mater Res 2000; 48:165-71. [PMID: 10331910 DOI: 10.1002/(sici)1097-4636(1999)48:2<165::aid-jbm11>3.0.co;2-#] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nickel-titanium (NiTi) offers many advantages for the fabrication of coronary stents: shape memory, superelasticity, and radiopacity. However, many authors highlighted the selective dissolution of Ni from the alloy during the corrosion process that could lead to potential toxicity. The improvement of the NiTi stent's corrosion resistance by different surface treatments (electropolishing, heat treatment, and nitric acid passivation) was reported in a previous article. In the present study a comparative biocompatibility evaluation of such stents was performed through in vitro and in vivo assays. A cell proliferation test was completed to evaluate the cytotoxicity of surface treated NiTi using human fibroblasts. Then a stent implantation was performed in rabbit paramuscular muscle to study the inflammatory response generated by the same implants. Cell proliferation tests generally indicated an in vitro biocompatibility of our samples similar to the control group. An in vivo implantation study demonstrated the gradual overall reduction with time of the fibrocellular capsule thickness surrounding the implants. After a 12-week implantation period, the fibrous capsules surrounding the different implants tended toward the same value of 0.07 mm, which suggested that all surface treatments produced a similar biological response. This low value of the fibrocellular capsule indicated that our NiTi surface treated implants were relatively inert.
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Affiliation(s)
- C Trépanier
- Biomechanics/Biomaterials Research Group, Biomedical Engineering Institute, Ecole Polytechnique of Montreal, Canada
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28
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Doucet S, Malekianpour M, Théroux P, Bilodeau L, Côté G, de Guise P, Dupuis J, Joyal M, Gosselin G, Tanguay JF, Juneau M, Harel F, Nattel S, Tardif JC, Lespérance J. Randomized trial comparing intravenous nitroglycerin and heparin for treatment of unstable angina secondary to restenosis after coronary artery angioplasty. Circulation 2000; 101:955-61. [PMID: 10704160 DOI: 10.1161/01.cir.101.9.955] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The treatment of unstable angina targets the specific pathophysiological thrombotic process at the site of the active culprit lesion. In unstable angina due to a restenotic lesion, smooth muscle cell proliferation and increased vasoreactivity may play a more important role than thrombus formation. Therefore, the relative benefits of nitroglycerin and heparin might differ in unstable angina associated with restenosis compared with classic unstable angina. METHODS AND RESULTS We randomized 200 patients hospitalized for unstable angina within 6 months after angioplasty (excluding those with intracoronary stents) to double-blind administration of intravenous nitroglycerin, heparin, their combination, or placebo for 63+/-30 hours. Recurrent angina occurred in 75% of patients in the placebo and heparin-alone groups, compared with 42.6% of patients in the nitroglycerin-alone group and 41.7% of patients in the nitroglycerin-plus-heparin group (P<0.003). Refractory angina requiring angiography occurred in 22.9%, 29.2%, 4. 3%, and 4.2% of patients, respectively (P<0.002). The odds ratios for being event free were 0.24 (95% CI, -0.13 to 0.45, P=0.0001) for nitroglycerin versus no nitroglycerin and 0.98 (95% CI, -0.55 to 1. 73, P=NS) for heparin versus no heparin. No patient died or suffered myocardial infarction. CONCLUSIONS Intravenous nitroglycerin is highly effective in preventing adverse ischemic events (recurrent or refractory angina) in patients with unstable angina secondary to restenosis, whereas heparin has no effect.
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Affiliation(s)
- S Doucet
- Cardiac Catheterization Laboratory and Department of Medicine, Montreal Heart Institute, Montreal, Quebec, Canada
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29
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Chorvátová A, Gendron L, Bilodeau L, Gallo-Payet N, Payet MD. A Ras-dependent chloride current activated by adrenocorticotropin in rat adrenal zona glomerulosa cells. Endocrinology 2000; 141:684-92. [PMID: 10650950 DOI: 10.1210/endo.141.2.7328] [Citation(s) in RCA: 16] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the present study, we report that ACTH induces a transient chloride current. The lack of correlation between ACTH-induced cAMP production and amplitude of the Cl- current, as well as the absence of stimulation by forskolin or 8Br-cAMP indicated that the ACTH-induced current was not cAMP-dependent. We explored the possibility that one or several elements of the Ras/Raf MAPK cascade were involved. Indeed, we found that ACTH at 10(-10) M induced activation of Ras. Inhibition of the current by QEHA peptide, a Gbetagamma sequestrant, demonstrated that Gbetagamma subunits transduced the message. Blockage of the Ras activation using an inhibitor of farnesyl transferase (BZA-5B) or the monoclonal antibody H-Ras(259) abrogated the current. Moreover, the addition of Ras-GTPyS in the pipette medium gave rise to the Cl- current. Treatment of the cells with BZA decreased the aldosterone secretion induced by 10(-10) M ACTH but not that induced by 10(-8) M ACTH, confirming the involvement of Ras in steroid secretion. We conclude that ACTH triggers a Cl- current through the activation of the Ras protein by Gbetagamma subunits. This current, activated at physiological ACTH concentrations (1 to 100 pM) where cAMP production is very low, could play a significant role in aldosterone production.
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Affiliation(s)
- A Chorvátová
- Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Québec, Canada
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30
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Abstract
Coronary rupture is a rare complication of percutaneous coronary intervention. However, it may be associated with serious hemodynamic consequences often leading to tamponade, myocardial infarction, emergency surgical intervention, or death. We report a successful percutaneous repair of a brisk left anterior descending coronary artery perforation by the implantation of a Magic Wallstent.
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Affiliation(s)
- T Hammoud
- Hemodynamic Laboratory, Department of Medicine, Montreal Heart Institute, Montreal, Quebec, Canada
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31
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Abstract
Adrenocorticotropic hormone (ACTH) is one of the principal activator of aldosterone secretion in rat zona glomerulosa cells, but its action on chloride currents is not well established. Here, we demonstrate that the hormone provoked a transient increase in a chloride current with a small unitary conductance estimated at 3.35 pS. Amplitude, as well as time-dependent increase of the ACTH-induced chloride current was independent of the intracellular cAMP concentration. In contrary, its decrease was sensitive to alkaline phosphatase and PKA-inhibitor H-89, indicating that protein phosphorylation, at least in part via PKA, is involved in the decline of the current.
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Affiliation(s)
- A Chorvatova
- Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Québec, Canada
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32
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Baldwin M, Mergler D, Larribe F, Bélanger S, Tardif R, Bilodeau L, Hudnell K. Bioindicator and exposure data for a population based study of manganese. Neurotoxicology 1999; 20:343-53. [PMID: 10385895] [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] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Exposure data and bioindicators were obtained for a study whose objective was detection of early manifestations of manganese (Mn) neurotoxicity in a population with potential environmental exposure. The study included persons with no history of neurotoxic workplace exposure in Southwest Quebec, drawn from seven postal code regions, defining a set of geographically contiguous zones. Blood samples were analyzed for total Mn (MnB), lead (PbB), total mercury (HgT) and serum iron (FeS). Drinking water samples from participants' residences were analyzed for manganese (MnW). At 4 sites, limited 24-hour high volume air samples for total particulates (TP) and PM10, were analyzed for Mn and Pb. Sociodemographic and dietary information was obtained by self-administered questionnaire. The geometric mean (GM) for MnB values (n = 297) was 7.14 micrograms/L. Levels of MnB in women (n = 156; GM 7.50 micrograms/L) were significantly higher than in men (n = 141; GM 6.75 micrograms/L). No relationship was found between MnB and PbB or HgT. FeS was significantly higher in men (GM 18.38 mumol/L) than women (GM 15.0 mumol/L). For women, MnB was correlated to FeS, with a tendency to decrease with increasing age. For men, no relationship was found between MnB levels and either FeS or age, although FeS showed a strong inverse relationship with age. The 24-hour mean levels of MnTP at the 4 sites varied between 0.009 microgram/m3 and 0.035 microgram/m3; intersite differences were not significant. For Mn in PM10 (MnPM10), mean values ranged from 0.007 microgram/m3 to 0.019 microgram/m3; intersite differences were significant. A total of 278 MnW samples were obtained, 16 from residences served by wells. The GM for MnW was 4.11 micrograms/L (range: 0.50-71.1 micrograms/L, excluding wells; MnW for wells ranged from non-detectable to 158.9 micrograms/L. Individually, there was no relation between MnW and MnB. Geographic analysis of the MnB and MnW data by an algorithm grouping contiguous postal code zones, combined with air data, lead to definition of a geographic parameter, distinguishing two regions relative to a former manganese alloy plant, which contributed significantly to MnB. A multiple regression model was developed, explaining 6.7% of the variability in MnB (F = 5.12; p < 0.001); when controlling for gender, geographic region with higher levels of airborne manganese and the frequency of consumption of cereals and leaf vegetables contributed positively to MnB levels, while serum iron was negatively related.
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Affiliation(s)
- M Baldwin
- Centre pour l'étude des interactions biologiques entre la santé et l'environnement (CINBIOSE), Université du Québec à Montréal, Canada.
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Abstract
We assessed the extent of the oblique effect (OE) and the meridional orientation effect (MOE) for a chromatic motion task using red/green gratings throughout an 80 degrees visual field. Four different stimulus orientations were tested. Generally, sensitivity to chromatic motion decreased with increasing eccentricity regardless of the visual field meridian. Also, sensitivity was highest for horizontal or vertical gratings, thus supporting the presence of an OE rather than of a MOE. The strength of the OE varied between subjects, but was present from the fovea to 20 degrees of eccentricity. At 40 degrees of eccentricity, chromatic motion was always perceived but the grating orientation did not consistently influence chromatic motion sensitivity. The present study confirmed our previous results on chromatic motion sensitivity and isoluminance ratios throughout the visual field. In addition, our data show that the chromatic system can exhibit OEs at lower spatial frequencies than is observed for the achromatic system.
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Affiliation(s)
- L Bilodeau
- Ecole d'Optométrie, Université de Montréal, Qué., Canada
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34
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Abstract
The capacity of the isolated chromatic system to perceive global motion was tested in a 40-deg visual field by use of random-dot kinematograms. The method of equivalent cone contrasts was used to directly compare the chromatic and the achromatic systems. The minimum number of dots necessary to correctly identify the motion direction was on the order of 20% for the isochromatic conditions, whereas thresholds were rarely obtained in the chromatic conditions. For both the isochromatic and the chromatic conditions, the central visual field was the most sensitive area, whereas the periphery was slightly less sensitive. This study suggests that the chromatic system does not efficiently integrate local motion cues to generate a global motion percept.
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Affiliation(s)
- L Bilodeau
- Ecole d'optométrie and Groupe de Recherche en Neuropsychologie Expérimentale, Université de Montréal, Canada
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35
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Abstract
Stent implantation represents a major step forward since the introduction of coronary angioplasty. As indications continue to expand, better understanding of the early and late biocompatibility issues appears critical. Persisting challenges to the use of intracoronary stents include the prevention of early thrombus formation and late neointima development. Different metals and designs have been evaluated in animal models and subsequently in patients. Polymer coatings have been proposed to improve the biocompatibility of metallic stents or to serve as matrix for drug delivery and they are currently undergoing clinical studies. The promises of a biodegradable stent have not yet been fulfilled although encouraging results have recently been reported. Continuous low dose-rate brachytherapy combining the scaffolding effect of the stent with localized radiation therapy has witnessed the development and early clinical testing of radioactive stents. The combined efforts of basic scientists and clinicians will undoubtedly contribute to the improvement of stent biocompatibility in the future.
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Affiliation(s)
- O F Bertrand
- Research Center, Montreal Heart Institute, Division of Experimental Medicine, McGill University, Quebec, Canada.
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36
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Abstract
Coronary angioplasty in a thombotic vein graft is associated with a low success rate and a high risk of periprocedural complications. The aspiration thrombectomy catheter is a new device designed to treat such cases. We report a first angioscopic description of thrombus removal by the AngioJet thrombectomy catheter.
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Affiliation(s)
- J Rodés
- Institut de Cardiologie de Montréal, Québec, Canada
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Rodés J, Côté G, Lespérance J, Bourassa MG, Doucet S, Bilodeau L, Bertrand OF, Harel F, Gallo R, Tardif JC. Prevention of restenosis after angioplasty in small coronary arteries with probucol. Circulation 1998; 97:429-36. [PMID: 9490236 DOI: 10.1161/01.cir.97.5.429] [Citation(s) in RCA: 59] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Restenosis remains the major limitation of coronary angioplasty. Coronary stents have reduced the incidence of restenosis in selected patients with relatively large vessels. No strategies to date have demonstrated a beneficial effect in vessels < 3.0 mm in diameter. We have shown in the MultiVitamins and Probucol (MVP) Trial that probucol, a potent antioxidant, reduces restenosis after balloon angioplasty. The purpose of this study was to determine whether the benefit of probucol therapy is maintained in the subgroup of patients with smaller coronary vessels. METHODS AND RESULTS We studied a subgroup of 189 patients included in the MVP trial who underwent successful balloon angioplasty of at least one coronary segment with a reference diameter < 3.0 mm. One month before angioplasty, patients were randomly assigned to one of four treatments: placebo, probucol (500 mg), multivitamins (beta-carotene 30000 IU, vitamin C 500 mg, and vitamin E 700 IU), or probucol plus multivitamins twice daily. The treatment was maintained until follow-up angiography was performed at 6 months. The mean reference diameter of this study population was 2.49+/-0.34 mm. Lumen loss was 0.12+/-0.34 mm for probucol, 0.25+/-0.43 mm for the combined treatment, 0.35+/-0.56 mm for vitamins, and 0.38+/-0.51 mm for placebo (P=.005 for probucol). Restenosis rates per segment were 20.0% for probucol, 28.6% for the combined treatment, 45.1% for vitamins, and 37.3% for placebo (P=.006 for probucol). CONCLUSIONS Probucol reduces lumen loss and restenosis rate after balloon angioplasty in small coronary arteries.
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Affiliation(s)
- J Rodés
- Department of Medicine, Montreal Heart Institute, Québec, Canada
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38
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39
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Bertrand OF, Mongrain R, Lehnert S, Bilodeau L, Tanguay JF, Laurier J, Côté G, Bourassa MG. Intravascular radiation therapy in atherosclerotic disease: promises and premises. Eur Heart J 1997; 18:1385-95. [PMID: 9458443 DOI: 10.1093/oxfordjournals.eurheartj.a015463] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- O F Bertrand
- Interventional Cardiology Laboratories, Montreal Heart Institute, Quebec, Canada
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40
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Tardif JC, Cöté G, Lespérance J, Bourassa M, Lambert J, Doucet S, Bilodeau L, Nattel S, de Guise P. Probucol and multivitamins in the prevention of restenosis after coronary angioplasty. Multivitamins and Probucol Study Group. N Engl J Med 1997; 337:365-72. [PMID: 9241125 DOI: 10.1056/nejm199708073370601] [Citation(s) in RCA: 446] [Impact Index Per Article: 16.5] [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: 02/04/2023]
Abstract
BACKGROUND Oxidizing metabolites generated at the site of coronary angioplasty can induce chain reactions that may lead to restenosis. Antioxidants may counter oxidative stress and modify neointimal formation and vascular remodeling. Experimental data and small clinical studies have suggested that antioxidants may prevent restenosis after angioplasty. In a double-blind, randomized trial, we studied whether drugs with antioxidant properties decrease the incidence and severity of restenosis after angioplasty. METHODS One month before angioplasty, 317 patients were randomly assigned to receive one of four treatments: placebo, probucol (500 mg), multivitamins (30,000 IU of beta carotene, 500 mg of vitamin C, and 700 IU of vitamin E), or both probucol and multivitamins-all given twice daily. Patients were treated for four weeks before and six months after angioplasty. Patients received an extra 1000 mg of probucol, 2000 IU of vitamin E, both probucol and vitamin E, or placebo 12 hours before angioplasty, according to their treatment assignments. Base-line and follow-up angiograms were interpreted by blinded investigators using a quantitative approach. RESULTS The mean (+/-SD) reduction in luminal diameter six months after angioplasty was 0.12 +/- 0.41 mm in the probucol group, 0.22 +/- 0.46 mm in the combined-treatment group, 0.33 +/- 0.51 in the multivitamin group, and 0.38 +/- 0.50 mm in the placebo group (P = 0.006 for those receiving vs. those not receiving probucol, and P = 0.70 for those receiving vs. those not receiving vitamins. Restenosis rates per segment were 20.7 percent in the probucol group, 28.9 percent in the combined-treatment group, 40.3 percent in the multivitamin group, and 38.9 percent in the placebo group (P = 0.003 for probucol vs. no probucol). The rates of repeat angioplasty were 11.2 percent. 16.2 percent, 24.4 percent, and 26.6 percent, respectively (P = 0.009 for probucol vs. no probucol). CONCLUSIONS The antioxidant probucol is effective in reducing the rate of restenosis after balloon coronary angioplasty.
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Affiliation(s)
- J C Tardif
- Department of Medicine, Montreal Heart Institute, QC, Canada
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41
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Abstract
Isoluminance and chromatic motion perception for red/green gratings were measured throughout an 80 deg visual field. Generally, the red/green isoluminance values changed with increasing eccentricity, i.e., observers increased the red luminance contrast for a fixed green luminance contrast. Enlarging the target size (to compensate for the cone density changes with eccentricity) and decreasing the spatial frequency (to compensate for receptive field property changes with eccentricity) did not change the isoluminance values within the central 20 deg, but the isoluminance ratios decreased beyond 20 deg. Our manipulations did not entirely compensate for a given eccentricity, which implies the need for a post-receptoral scaling function for the perception of drifting chromatic stimuli. Further, the results for isoluminance show heterogeneity between the visual field meridians where the red to green luminance ratio tends to be greater in the superior visual field. In our present conditions, chromatic motion was always perceived (up to 40 deg of eccentricity), but sensitivity generally decreased with increasing eccentricity. The inferior visual field was found to be the most sensitive to chromatic motion. We propose that the lower visual field and not the superior visual field is specialized for colour motion information.
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Affiliation(s)
- L Bilodeau
- Ecole d'optométrie and Groupe de Recherche en Neuropsychologie Expérimentale, Université de Montréal, Québec, Canada. /http
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42
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Bertrand OF, Bonan R, Bilodeau L, Tanguay JF, Tardif JC, Rodés J, Joyal M, Crépeau J, Côté G. Management of resistant coronary lesions by the cutting balloon catheter: initial experience. Cathet Cardiovasc Diagn 1997; 41:179-84. [PMID: 9184293 DOI: 10.1002/(sici)1097-0304(199706)41:2<179::aid-ccd16>3.0.co;2-l] [Citation(s) in RCA: 19] [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: 02/04/2023]
Abstract
Resistant coronary lesions remain a challenge for modern angioplasty. Classical approaches include high-pressure inflations, prolonged inflations, or balloon oversizing. More recently, new technologies like rotablator, atherectomy, or laser have been proposed as adjunct to balloon angioplasty for the treatment of these specific lesions. However, all these technologies remain more difficult to handle, costly, and they do not offer long-term benefit over conventional methods. Therefore, a simple device such as the cutting balloon catheter which has been developed from a standard over the wire balloon catheter, may prove to be useful in resistant coronary lesions. We present our single center experience using the new cutting balloon catheter in six resistant lesions.
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43
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Drolet P, Bilodeau L, Chorvatova A, Laflamme L, Gallo-Payet N, Payet MD. Inhibition of the T-type Ca2+ current by the dopamine D1 receptor in rat adrenal glomerulosa cells: requirement of the combined action of the G betagamma protein subunit and cyclic adenosine 3',5'-monophosphate. Mol Endocrinol 1997; 11:503-14. [PMID: 9092802 DOI: 10.1210/mend.11.4.9910] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 02/04/2023] Open
Abstract
Modulation of ionic Ca2+ currents by dopamine (DA) could play a pivotal role in the control of steroid secretion by the rat adrenal glomerulosa cells. In the present study, we report that DA decreases the T-type Ca2+ current amplitude in these cells. The use of pharmacological agonists and antagonists reveals that this effect is mediated by activation of the D1-like receptors. Modulation by cAMP is complex inasmuch as preincubation of the cells with 8-Br-cAMP or the specific adenylyl cyclase inhibitor, 2',3'-dideoxyadenosine, have no effect per se, but prevent the DA-induced inhibition. The inhibitory effect of DA was abolished by addition of GDPbetaS to the pipette medium but not by pertussis toxin. If a cell is dialyzed with medium containing G alpha(s)-GDP, the inhibitory effect is reduced and cannot be recovered by the addition of GTPgammaS, indicating that the alpha(s) is not involved, but rather the betagamma-subunit. Indeed, DA-induced inhibition was mimicked by G betagamma in the pipette and 8-Br-cAMP in the bath. Similarly, G betagamma release from the activation of the AT1 receptor of angiotensin II did affect the current amplitude only in the presence of 8-Br-cAMP in the bath. The mitogen-activated protein kinase cascade, which can be activated by receptors coupled to Gs, was not involved as shown by the lack of activation of p42mapk by DA and the absence of effect of the mitogen-activated protein kinase inhibitor, PD 098059, on the DA-induced inhibition. Because the binding of G betagamma-subunits to various effectors involves the motif QXXER, we therefore tested the effect of the QEHA peptide on the inhibition of the T-type Ca2+ current induced by DA. The peptide, added to the medium pipette (200 microM), abolished the effect of DA. We conclude that the presence of the G betagamma and an increase in cAMP concentration are both required to inhibit the T-type Ca2+ current in rat adrenal glomerulosa cells.
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Affiliation(s)
- P Drolet
- Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Quebec, Canada
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44
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Grazzini E, Durroux T, Payet MD, Bilodeau L, Gallo-Payet N, Guillon G. Membrane-delimited G protein-mediated coupling between V1a vasopressin receptor and dihydropyridine binding sites in rat glomerulosa cells. Mol Pharmacol 1996; 50:1273-83. [PMID: 8913359] [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] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In rat glomerulosa cells, vasopressin stimulates intracellular calcium mobilization via at least two distinct mechanisms: the release of calcium from inositol-1,4,5-P3-sensitive stores and the activation of transmembrane calcium influx. In this study, we focused on the second mechanism through three experimental approaches. By videomicroscopically examining Fura-2-loaded cells, we demonstrate that vasopressin induces a dose-dependent and receptor-mediated calcium influx fully inhibited by either 1 microM nifedipine or a pertussis toxin pretreatment and potentiated by 1 microM BAY K 8644. Patch-clamp experiments also indicate that vasopressin stimulates L-type calcium current by 87% and only weakly inhibits T-type calcium current. To further characterize the coupling between the vasopressin receptor and the dihydropyridine calcium channel, we performed binding studies using tritiated nitrendipine. With this technique, we showed that on intact cells, vasopressin is able to increase the specific binding of tritiated nitrendipine in a dose-dependent manner (Kact = 2 nM). Pharmacological studies using a series of vasopressin analogs revealed that this effect is mediated via a V1a vasopressin receptor subtype. Furthermore, the vasopressin-stimulated nitrendipine binding was sensitive to pertussis toxin pretreatment, which affected only the maximum binding capacity of nitrendipine-binding sites. More interestingly, we demonstrate that vasopressin still increases nitrendipine binding to plasma membrane preparation and that GTP is absolutely necessary for such a hormonal effect. Altogether, these data confirm the existence of a tight and direct coupling between the V1a vasopressin receptor and a dihydropyridine calcium channel via a pertussis toxin-sensitive G protein.
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Affiliation(s)
- E Grazzini
- Centre National de la Recherche Scientifique, Institute National de la Santé et de la Recherche Médicale de Pharmacologie/Endocrinologie U 401, Montpellier, France
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45
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Gallo-Payet N, Grazzini E, Côté M, Chouinard L, Chorvátová A, Bilodeau L, Payet MD, Guillon G. Role of Ca2+ in the action of adrenocorticotropin in cultured human adrenal glomerulosa cells. J Clin Invest 1996; 98:460-6. [PMID: 8755657 PMCID: PMC507450 DOI: 10.1172/jci118812] [Citation(s) in RCA: 53] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The present report details the role of Ca2+ in the early events of ACTH action in human adrenal glomerulosa cells. Threshold stimulations of both aldosterone and cAMP production were obtained with a concentration of 10 pM ACTH, an ED50 of 0.1 nM, and maximal aldosterone stimulation (5.5-fold increase over control) at 10 nM ACTH. ACTH also induced a sustained increase of intracellular calcium ([Ca2+]i) with maximal stimulation of 1.6 +/- 0.1-fold over control values. This increase does not involve mobilization of calcium from intracellular pools since no response was observed in Ca2+-free medium or in the presence of nifedipine, suggesting the involvement of Ca2+ influx by L-type Ca2+ channels. This was confirmed by patch clamp studies that demonstrated that ACTH stimulates L-type Ca2+ channels. Moreover, the Ca2+ ion is not required for ACTH binding to its receptor, but is essential for sustained cAMP production and aldosterone secretion after ACTH stimulation. These results indicate that, in human adrenal glomerulosa cells, a positive feedback loop between adenylyl cyclase-protein kinase A-Ca2+ channels ensures a slow but sustained [Ca2+]i increase that is responsible for sustained cAMP production and aldosterone secretion.
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Affiliation(s)
- N Gallo-Payet
- Service of Endocrinology, Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
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46
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Payet MD, Bilodeau L, Drolet P, Ibarrondo J, Guillon G, Gallo-Payet N. Modulation of a Ca(2+)-activated K+ channel by angiotensin II in rat adrenal glomerulosa cells: involvement of a G protein. Mol Endocrinol 1995; 9:935-47. [PMID: 7476991 DOI: 10.1210/mend.9.8.7476991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In the present study, we demonstrate the presence of Ca(2+)-activated K+ channels in rat glomerulosa cells. We find that angiotensin II (Ang II) inhibits this charybdotoxin-sensitive current. The effect of Ang II was dose-dependent with an inhibition constant (Ki) of 0.98 nM and a maximal effect observed at 200 nM. Time course of the blockage was as rapid as the one induced by charybdotoxin. This effect is mediated by the AT1 receptor subtype of Ang II, since it is blocked by DUP 753 but is unaffected by CGP 42112. Activation of protein kinase C by phorbol dibutyrate (1 microM) or dialysis of the cell with inositol 1,4,5-triphosphate (20 microM) were ineffective in blocking the current. However, experiments done with GDP beta S and GTP gamma S indicated that a G protein was involved. The inhibitory effect of Ang II was not pertussis toxin-sensitive, which excludes Gi protein, but was abrogated if an antibody raised against the alpha-subunit of the Gq/11 protein was present in the patch pipette medium. Further analysis showed that the Ca(2+)-activated K+ channel was able to modulate the membrane potential according to the level of intracellular calcium concentration ([Ca2+]i). Whereas a thapsigargin-induced increase in [Ca2+]i hyperpolarized the membrane, this effect was not observed when Ang II was used to increase [Ca2+]i because of the blockage of the Ca(2+)-activated K+ current. The blockage of Ca(2+)-activated K+ current by Ang II would result in a synergistic effect on the Ang II-induced depolarization, thus favoring Ca2+ influx, an event essential to secretion.
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Affiliation(s)
- M D Payet
- Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Quebec, Canada
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47
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Apple FS, Bilodeau L, Preese LM, Benson P. Clinical implementation of a rapid, automated assay for assessing fetal lung maturity. J Reprod Med 1994; 39:883-7. [PMID: 7853280] [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: 01/27/2023]
Abstract
We retrospectively determined cutoff levels and implemented the use of the TDxFLx assay in assessing the likelihood or absence of respiratory distress syndrome or fetal lung maturity (FLM) in a high-risk obstetric setting when compared to the lecithin/sphingomyelin (L/S) ratio and disaturated lecithin (DSL) measurements. Using a mature TDxFLx cutoff value of > or = 50 mg/g and an immature cutoff value of < 20 mg/g, 88% of L/S ratio and DSL measurements could be eliminated without compromise to the patient. The > or = 50 mg/g TDxFLx cutoff value resulted in a sensitivity of 100% and specificity of 88%. We also recommend the use of the TDxFLx assay as a screening test in diabetic pregnancies. More timely patient care occurred when the rapid TDxFLx assay was implemented by the laboratory and used by clinicians.
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Affiliation(s)
- F S Apple
- Department of Laboratory Medicine and Pathology, Hennepin County Medical Center, Minneapolis, MN 55415
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48
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Lespe´rance J, Campeau L, Laurier J, Bois M, Dyrda I, Bilodeau L, Doucet S, Hudon G. Reproducibility (true change) of coronary artery saphenous vein graft measurements using quantitative angiography. Atherosclerosis 1994. [DOI: 10.1016/0021-9150(94)94192-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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49
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Abstract
Ionic currents of primary cultured glomerulosa cells from human adrenal glands were studied with the patch-clamp technique. Two types of outward K+ currents and two types of inward Ca2+ currents were described. The transient outward K+ current activated at potential positive to -40 mV and demonstrated a marked time-dependent inactivation. It was blocked by 4-aminopyridine but not tetraethylammonium. A second type of outward current activated rapidly at the depolarization onset and then increased slowly with no time-dependent inactivation. The transient inward T-type Ca2+ current was activated for potential positive to -60 mV with a maximal current amplitude at -30 mV and zero current voltage at +40 mV; it was completely inactivated for membrane potential positive to -40 mV. The pharmacological studies of the T-type channel showed that Ni2+ was a potent blocker but that the channel was not sensitive to dihydropyridine. The long-lasting inward Ca2+ current was activated for potentials positive to -20 mV with a maximum current amplitude at +70 mV. This current was increased by the agonist Bay K 8644 and blocked by the antagonist nifedipine; in addition, it was blocked by Cd2+ but less sensitive to Ni2+. This study revealed that glomerulosa cells from human adrenal demonstrated the presence of K+ and Ca2+ currents similar to those found in rat and bovine cells. Moreover, the main stimuli of aldosterone secretion, ACTH and angiotensin II, induce an increase in aldosterone secretion which is inhibited in a Ca(2+)-free external medium.
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Affiliation(s)
- M D Payet
- Département de Physiologie et Biophysique, Faculté de Médecine, Université de Sherbrooke, Quebec, Canada
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Affiliation(s)
- L Bilodeau
- Department of Medicine, School of Medicine, University of Alabama at Birmingham 35294
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