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Kim JS, Choi SW, Park YG, Kim SJ, Choi CH, Cha MJ, Chang JH. Impact of High-Dose Irradiation on Human iPSC-Derived Cardiomyocytes Using Multi-Electrode Arrays: Implications for the Antiarrhythmic Effects of Cardiac Radioablation. Int J Mol Sci 2021; 23:ijms23010351. [PMID: 35008778 PMCID: PMC8745341 DOI: 10.3390/ijms23010351] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 12/19/2022] Open
Abstract
Cardiac radioablation is emerging as an alternative option for refractory ventricular arrhythmias. However, the immediate acute effect of high-dose irradiation on human cardiomyocytes remains poorly known. We measured the electrical activities of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) upon irradiation with 0, 20, 25, 30, 40, and 50 Gy using a multi-electrode array, and cardiomyocyte function gene levels were evaluated. iPSC-CMs showed to recover their electrophysiological activities (total active electrode, spike amplitude and slope, and corrected field potential duration) within 3–6 h from the acute effects of high-dose irradiation. The beat rate immediately increased until 3 h after irradiation, but it steadily decreased afterward. Conduction velocity slowed in cells irradiated with ≥25 Gy until 6–12 h and recovered within 24 h; notably, 20 and 25 Gy-treated groups showed subsequent continuous increase. At day 7 post-irradiation, except for cTnT, cardiomyocyte function gene levels increased with increasing irradiation dose, but uniquely peaked at 25–30 Gy. Altogether, high-dose irradiation immediately and reversibly modifies the electrical conduction of cardiomyocytes. Thus, compensatory mechanisms at the cellular level may be activated after the high-dose irradiation acute effects, thereby, contributing to the immediate antiarrhythmic outcome of cardiac radioablation for refractory ventricular arrhythmias.
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Affiliation(s)
- Jae Sik Kim
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul 03080, Korea; (J.S.K.); (C.H.C.)
- Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Seoul 05278, Korea
| | - Seong Woo Choi
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea;
| | - Yun-Gwi Park
- Stem Cell Research Institute, T&R Biofab Co., Ltd., Siheung 15073, Korea;
| | - Sung Joon Kim
- Department of Physiology & Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 03080, Korea;
| | - Chang Heon Choi
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul 03080, Korea; (J.S.K.); (C.H.C.)
- Department of Radiation Oncology, Seoul National University Hospital, Seoul 03080, Korea
| | - Myung-Jin Cha
- Division of Cardiology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
- Correspondence: (M.-J.C.); (J.H.C.); Tel.: +82-2-3010-3321 (M.-J.C.); +82-2-2072-4940 (J.H.C.)
| | - Ji Hyun Chang
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul 03080, Korea; (J.S.K.); (C.H.C.)
- Department of Radiation Oncology, Seoul National University Hospital, Seoul 03080, Korea
- Correspondence: (M.-J.C.); (J.H.C.); Tel.: +82-2-3010-3321 (M.-J.C.); +82-2-2072-4940 (J.H.C.)
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Zhu S, Xu J, Chen H, Lv W. Ultrasonic-Assisted Enzymolysis Extraction and Protective Effect on Injured Cardiomyocytes in Mice of Flavonoids from Prunus mume Blossom. Molecules 2021; 26:molecules26195818. [PMID: 34641361 PMCID: PMC8510299 DOI: 10.3390/molecules26195818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/15/2021] [Accepted: 09/22/2021] [Indexed: 11/22/2022] Open
Abstract
Prunus mume blossom is an edible flower that has been used in traditional Chinese medicine for thousands of years. Flavonoids are one of the most active substances in Prunus mume blossoms. The optimal ultrasonic-assisted enzymatic extraction of flavonoids from Prunus mume blossom (FPMB), the components of FPMB, and its protective effect on injured cardiomyocytes were investigated in this study. According to our results, the optimal extraction process for FPMB is as follows: cellulase at 2.0%, ultrasonic power at 300 W, ultrasonic enzymolysis for 30 min, and an enzymolysis temperature of 40 °C. FPMB significantly promoted the survival rate of cardiomyocytes and reduced the concentration of reactive oxygen species (ROS). FPMB also improved the activities of proteases caspase-3, caspase-8, and caspase-9 in cardiomyocytes. The cardiomyocyte apoptosis rate in mice was significantly reduced by exposure to FPMB. These results suggest that the extraction rate of FPMB may be improved by an ultrasonic-assisted enzymatic method. FPMB has a protective effect on the injured cardiomyocytes.
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Affiliation(s)
- Shengnan Zhu
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China;
| | - Jicheng Xu
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China;
- Correspondence: ; Tel.: +86-1-385-530-3015
| | - Huizhi Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China;
| | - Weiqiao Lv
- College of Engineering, China Agricultural University, Beijing 100083, China;
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Müller D, Klamt T, Gentemann L, Heisterkamp A, Kalies SMK. Evaluation of laser induced sarcomere micro-damage: Role of damage extent and location in cardiomyocytes. PLoS One 2021; 16:e0252346. [PMID: 34086732 PMCID: PMC8177425 DOI: 10.1371/journal.pone.0252346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 05/12/2021] [Indexed: 11/18/2022] Open
Abstract
Whereas it is evident that a well aligned and regular sarcomeric structure in cardiomyocytes is vital for heart function, considerably less is known about the contribution of individual elements to the mechanics of the entire cell. For instance, it is unclear whether altered Z-disc elements are the reason or the outcome of related cardiomyopathies. Therefore, it is crucial to gain more insight into this cellular organization. This study utilizes femtosecond laser-based nanosurgery to better understand sarcomeres and their repair upon damage. We investigated the influence of the extent and the location of the Z-disc damage. A single, three, five or ten Z-disc ablations were performed in neonatal rat cardiomyocytes. We employed image-based analysis using a self-written software together with different already published algorithms. We observed that cardiomyocyte survival associated with the damage extent, but not with the cell area or the total number of Z-discs per cell. The cell survival is independent of the damage position and can be compensated. However, the sarcomere alignment/orientation is changing over time after ablation. The contraction time is also independent of the extent of damage for the tested parameters. Additionally, we observed shortening rates between 6–7% of the initial sarcomere length in laser treated cardiomyocytes. This rate is an important indicator for force generation in myocytes. In conclusion, femtosecond laser-based nanosurgery together with image-based sarcomere tracking is a powerful tool to better understand the Z-disc complex and its force propagation function and role in cellular mechanisms.
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Affiliation(s)
- Dominik Müller
- Institute of Quantum Optics, Leibniz University Hannover, Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
- * E-mail:
| | - Thorben Klamt
- Institute of Quantum Optics, Leibniz University Hannover, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Lara Gentemann
- Institute of Quantum Optics, Leibniz University Hannover, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Alexander Heisterkamp
- Institute of Quantum Optics, Leibniz University Hannover, Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Stefan Michael Klaus Kalies
- Institute of Quantum Optics, Leibniz University Hannover, Hannover, Germany
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
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Keshmiri Neghab H, Goliaei B, Saboury AA, Esmaeeli Djavid G, Pornour M, Hong J, Grusch M. Modulation of cardiac optogenetics by vitamin A. Biofactors 2019; 45:983-990. [PMID: 31509323 DOI: 10.1002/biof.1564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 08/16/2019] [Indexed: 01/03/2023]
Abstract
Cardiac optogenetics is an emergent research area and refers to the delivery of light-activated proteins to excitable heart tissue and the subsequent use of light for controlling the electrical function with high spatial and temporal resolution. Channelrhodopsin-2 (ChR2) is a light-sensitive ion channel with the chromophore, all trans retinal, derived from vitamin A (all-trans-retinol; retinol). In this study, we explored whether exogenous vitamin A can be a limiting factor in the light responsiveness of cardiomyocytes-expressing ChR2. We showed that in cardiomyocytes virally transduced with ChR2 (H134R)-enhanced yellow fluorescent protein, vitamin A supplements lower than 10 μM significantly increased ChR2 expression. Adding 1 μM vitamin A changed light-induced transmembrane potential difference significantly, whereas 5 μM dramatically induced membrane depolarization and triggered intracellular calcium elevation. We concluded that vitamin A supplementation can modulate the efficiency of ChR2 and provide a complementary strategy for improving the performance of optogenetic tools.
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Affiliation(s)
| | - Bahram Goliaei
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Ali A Saboury
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Gholamreza Esmaeeli Djavid
- Department of Photo Healing and Regeneration, Medical Laser Research Center, Yara Institute Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
| | - Majid Pornour
- Department of Photo Healing and Regeneration, Medical Laser Research Center, Yara Institute Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
| | - Jun Hong
- School of Life Sciences, Henan University, Kaifeng, China
| | - Michael Grusch
- Department of Medicine I, Comprehensive Cancer Center Vienna, Institute of Cancer Research, Medical University of Vienna, Vienna, Austria
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Barjaktarovic Z, Merl-Pham J, Braga-Tanaka I, Tanaka S, Hauck SM, Saran A, Mancuso M, Atkinson MJ, Tapio S, Azimzadeh O. Hyperacetylation of Cardiac Mitochondrial Proteins Is Associated with Metabolic Impairment and Sirtuin Downregulation after Chronic Total Body Irradiation of ApoE -/- Mice. Int J Mol Sci 2019; 20:ijms20205239. [PMID: 31652604 PMCID: PMC6829468 DOI: 10.3390/ijms20205239] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 10/17/2019] [Accepted: 10/19/2019] [Indexed: 12/14/2022] Open
Abstract
Chronic exposure to low-dose ionizing radiation is associated with an increased risk of cardiovascular disease. Alteration in energy metabolism has been suggested to contribute to radiation-induced heart pathology, mitochondrial dysfunction being a hallmark of this disease. The goal of this study was to investigate the regulatory role of acetylation in heart mitochondria in the long-term response to chronic radiation. ApoE-deficient C57Bl/6J mice were exposed to low-dose-rate (20 mGy/day) gamma radiation for 300 days, resulting in a cumulative total body dose of 6.0 Gy. Heart mitochondria were isolated and analyzed using quantitative proteomics. Radiation-induced proteome and acetylome alterations were further validated using immunoblotting, enzyme activity assays, and ELISA. In total, 71 proteins showed peptides with a changed acetylation status following irradiation. The great majority (94%) of the hyperacetylated proteins were involved in the TCA cycle, fatty acid oxidation, oxidative stress response and sirtuin pathway. The elevated acetylation patterns coincided with reduced activity of mitochondrial sirtuins, increased the level of Acetyl-CoA, and were accompanied by inactivation of major cardiac metabolic regulators PGC-1 alpha and PPAR alpha. These observations suggest that the changes in mitochondrial acetylation after irradiation is associated with impairment of heart metabolism. We propose a novel mechanism involved in the development of late cardiac damage following chronic irradiation.
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Affiliation(s)
- Zarko Barjaktarovic
- Institute of Radiation Biology, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Institute of Radiation Biology, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
- Agency for Medicines and Medical Devices of Montenegro, 81000 Podgorica, Montenegro.
| | - Juliane Merl-Pham
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 80939 München, Germany.
| | | | - Satoshi Tanaka
- Institute for Environmental Sciences (IES), Rokkasho, Aomori 039-3213, Japan.
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 80939 München, Germany.
| | - Anna Saran
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), 76 00196 Rome, Italy.
| | - Mariateresa Mancuso
- Laboratory of Biomedical Technologies, Agenzia Nazionale per le Nuove Tecnologie, l'Energia e lo Sviluppo Economico Sostenibile (ENEA), 76 00196 Rome, Italy.
| | - Michael J Atkinson
- Institute of Radiation Biology, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Institute of Radiation Biology, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
- Chair of Radiation Biology, Technical University Munich, 80333 Munich, Germany.
| | - Soile Tapio
- Institute of Radiation Biology, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Institute of Radiation Biology, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
| | - Omid Azimzadeh
- Institute of Radiation Biology, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Institute of Radiation Biology, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
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Beheshti A, McDonald JT, Miller J, Grabham P, Costes SV. GeneLab Database Analyses Suggest Long-Term Impact of Space Radiation on the Cardiovascular System by the Activation of FYN Through Reactive Oxygen Species. Int J Mol Sci 2019; 20:ijms20030661. [PMID: 30717456 PMCID: PMC6387434 DOI: 10.3390/ijms20030661] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 12/17/2022] Open
Abstract
Space radiation has recently been considered a risk factor for astronauts’ cardiac health. As an example, for the case of how to query and identify datasets within NASA’s GeneLab database and demonstrate the database utility, we used an unbiased systems biology method for identifying key genes/drivers for the contribution of space radiation on the cardiovascular system. This knowledge can contribute to designing appropriate experiments targeting these specific pathways. Microarray data from cardiomyocytes of male C57BL/6 mice followed-up for 28 days after exposure to 900 mGy of 1 GeV proton or 150 mGy of 1 GeV/n 56Fe were compared to human endothelial cells (HUVECs) cultured for 7 days on the International Space Station (ISS). We observed common molecular pathways between simulated space radiation and HUVECs flown on the ISS. The analysis suggests FYN is the central driver/hub for the cardiovascular response to space radiation: the known oxidative stress induced immediately following radiation would only be transient and would upregulate FYN, which in turn would reduce reactive oxygen species (ROS) levels, protecting the cardiovascular system. The transcriptomic signature of exposure to protons was also much closer to the spaceflight signature than 56Fe’s signature. To our knowledge, this is the first time GeneLab datasets were utilized to provide potential biological indications that the majority of ions on the ISS are protons, clearly illustrating the power of omics analysis. More generally, this work also demonstrates how to combine animal radiation studies done on the ground and spaceflight studies to evaluate human risk in space.
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Affiliation(s)
- Afshin Beheshti
- WYLE Labs, NASA Ames Research Center, Moffett Field CA 94035, USA.
| | - J Tyson McDonald
- Department of Physics, Hampton University, Hampton, VA 23668 USA.
| | - Jack Miller
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Peter Grabham
- Center for Radiological Research, Columbia University, New York, NY 10032, USA.
| | - Sylvain V Costes
- NASA Ames Research Center, Space Biosciences Division, Moffett Field, CA 94035, USA.
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Wang H, Zhang J, Hu SH, Tan SZ, Zhang B, Zhou HM, Peng RY. Real-time Microwave Exposure Induces Calcium Efflux in Primary Hippocampal Neurons and Primary Cardiomyocytes. Biomed Environ Sci 2018; 31:561-571. [PMID: 30231960 DOI: 10.3967/bes2018.077] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVE To detect the effects of microwave on calcium levels in primary hippocampal neurons and primary cardiomyocytes by the real-time microwave exposure combined with laser scanning confocal microscopy. METHODS The primary hippocampal neurons and primary cardiomyocytes were cultured and labeled with probes, including Fluo-4 AM, Mag-Fluo-AM, and Rhod-2, to reflect the levels of whole calcium [Ca2+], endoplasmic reticulum calcium [Ca2+]ER, and mitochondrial calcium [Ca2+]MIT, respectively. Then, the cells were exposed to a pulsed microwave of 2.856 GHz with specific absorption rate (SAR) values of 0, 4, and 40 W/kg for 6 min to observe the changes in calcium levels. RESULTS The results showed that the 4 and 40 W/kg microwave radiation caused a significant decrease in the levels of [Ca2+], [Ca2+]ER, and [Ca2+]MIT in primary hippocampal neurons. In the primary cardiomyocytes, only the 40 W/kg microwave radiation caused the decrease in the levels of [Ca2+], [Ca2+]ER, and [Ca2+]MIT. Primary hippocampal neurons were more sensitive to microwave exposure than primary cardiomyocytes. The mitochondria were more sensitive to microwave exposure than the endoplasmic reticulum. CONCLUSION The calcium efflux was occurred during microwave exposure in primary hippocampal neurons and primary cardiomyocytes. Additionally, neurons and mitochondria were sensitive cells and organelle respectively.
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Affiliation(s)
- Hui Wang
- Department of Experimental Pathology, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
| | - Jing Zhang
- Department of Experimental Pathology, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
| | - Shao Hua Hu
- Department of Experimental Pathology, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China; Department of Clinical Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai 200040, China
| | - Sheng Zhi Tan
- Department of Experimental Pathology, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
| | - Bo Zhang
- Department of Experimental Pathology, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
| | - Hong Mei Zhou
- Department of Experimental Pathology, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
| | - Rui Yun Peng
- Department of Experimental Pathology, Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
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Gramatyka M, Skorupa A, Sokół M. Nuclear magnetic resonance spectroscopy reveals metabolic changes in living cardiomyocytes after low doses of ionizing radiation. Acta Biochim Pol 2018; 65:309-318. [PMID: 29906297 DOI: 10.18388/abp.2018_2568] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/23/2018] [Accepted: 05/18/2018] [Indexed: 11/10/2022]
Abstract
Several lines of evidence indicate that exposure of heart to ionizing radiation increases the risk of cardiotoxicity manifested by heart dysfunction and cardiovascular diseases. It was initially believed that the heart is an organ relatively resistant to radiation. Currently, however, it is suspected that even low doses of radiation (< 2 Gy) may have a negative impact on the cardiovascular system. Cardiotoxicity of ionizing radiation is associated with metabolic changes observed in cardiac cells injured by radiation. In this study, we used human cardiomyocytes as a model system, and studied their metabolic response to radiation using high-resolution magic angle spinning nuclear magnetic resonance techniques (HR-MAS NMR). Human cardiomyocytes cultured in vitro were exposed to ionizing radiation and their survival was assessed by clonogenic assay. Changes in apoptosis intensity and cell cycle distribution after the irradiation were measured as well. NMR spectra of cardiomyocytes were acquired using Bruker Avance 400 MHz spectrometer at a spinning rate of 3200 Hz. Survival of cardiomyocytes after NMR experiments was assessed by the Trypan blue exclusion assay. Exposure of cardiomyocytes to small doses of ionizing radiation had no effect on cell proliferation potential and intensity of cell death. However, analysis of metabolic profiles revealed changes in lipids, threonine, glycine, glycerophosphocholine, choline, valine, isoleucine, glutamate, reduced glutathione and taurine metabolism. The results of this study showed that ionizing radiation affects metabolic profiles of cardiomyocytes even at low doses, which potentially have no effect on cell viability.
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Affiliation(s)
- Michalina Gramatyka
- Department of Medical Physics, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland
| | - Agnieszka Skorupa
- Department of Medical Physics, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland
| | - Maria Sokół
- Department of Medical Physics, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Gliwice, Poland
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Becker BV, Seeger T, Beiert T, Antwerpen M, Palnek A, Port M, Ullmann R. Impact of Ionizing Radiation on Electrophysiological Behavior of Human-induced Ipsc-derived Cardiomyocytes on Multielectrode Arrays. Health Phys 2018; 115:21-28. [PMID: 29787427 DOI: 10.1097/hp.0000000000000817] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cardiac arrhythmia presumably induced through cardiac fibrosis is a recurrent long-term consequence of exposure to ionizing radiation. However, there is also evidence that cardiac arrhythmia can occur in patients shortly after irradiation. In this study, the authors employed multielectrode arrays to investigate the short-term effects of x-ray radiation on the electrophysiological behavior of cardiomyocytes derived from human-induced pluripotent stem cells. These cardiomyocytes with spontaneous pacemaker activity were cultured on single-well multielectrode arrays. After exposure to 0, 0.5, 1, 2, 5, 10 Gy x-ray radiation, electrical activity was measured at time points ranging from 10 min to 96 h. RNA sequencing was employed to verify the expression of genes specifically involved in cardiomyocyte differentiation and function. A decrease in beating rate was observed after irradiation with 5 and 10 Gy starting 48 h after exposure. Cells exposed to higher doses of radiation were more prone to show changes in electrophysiological spatial distribution. No radiation-induced effects with respect to the corrected QT interval were detectable. Gene expression analysis showed up regulation of typical cardiac features like ACTC1 or HCN4. In this study, early dose-dependent changes in electrophysiological behavior were determined after x-ray irradiation. Results point towards a dose-dependent effect on pacemaker function of cardiomyocytes and indicate a possible connection between irradiation and short-term changes in electrophysiological cardiac function. Cardiomyocytes derived from human-induced pluripotent stem cells on multielectrode arrays represent a promising in vitro cardiac-modeling system for preclinical studies.
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Affiliation(s)
- Benjamin V Becker
- Bundeswehr Institute of Radiobiology affiliated with Ulm University, Genomics II, Neuherbergstrasse 11, 80804, Munich, Germany
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80804, Munich, Germany
| | - Thomas Beiert
- Department of Cardiology, University Hospital Bonn, Sigmund-Freud-Strasse 25, 53105, Bonn, Germany
| | - Markus Antwerpen
- Bundeswehr Institute of Microbiology, Neuherbergstrasse 11, 80804, Munich, Germany
| | - Andreas Palnek
- Bundeswehr Institute of Radiobiology affiliated with Ulm University, Genomics II, Neuherbergstrasse 11, 80804, Munich, Germany
| | - Matthias Port
- Bundeswehr Institute of Radiobiology affiliated with Ulm University, Head of Institute, Neuherbergstrasse 11, 80804, Munich, Germany
| | - Reinhard Ullmann
- Bundeswehr Institute of Radiobiology affiliated with Ulm University, Genomics II Department Head, Neuherbergstrasse 11, 80804, Munich, Germany
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10
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Savchenko A, Cherkas V, Liu C, Braun GB, Kleschevnikov A, Miller YI, Molokanova E. Graphene biointerfaces for optical stimulation of cells. Sci Adv 2018; 4:eaat0351. [PMID: 29795786 PMCID: PMC5959318 DOI: 10.1126/sciadv.aat0351] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/29/2018] [Indexed: 05/17/2023]
Abstract
Noninvasive stimulation of cells is crucial for the accurate examination and control of their function both at the cellular and the system levels. To address this need, we present a pioneering optical stimulation platform that does not require genetic modification of cells but instead capitalizes on unique optoelectronic properties of graphene, including its ability to efficiently convert light into electricity. We report the first studies of optical stimulation of cardiomyocytes via graphene-based biointerfaces (G-biointerfaces) in substrate-based and dispersible configurations. The efficiency of stimulation via G-biointerfaces is independent of light wavelength but can be tuned by changing the light intensity. We demonstrate that an all-optical evaluation of use-dependent drug effects in vitro can be enabled using substrate-based G-biointerfaces. Furthermore, using dispersible G-biointerfaces in vivo, we perform optical modulation of the heart activity in zebrafish embryos. Our discovery is expected to empower numerous fundamental and translational biomedical studies.
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Affiliation(s)
- Alex Savchenko
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
- Corresponding author. (E.M.); (A.S.)
| | - Volodymyr Cherkas
- Department of Molecular Biophysics, Bogomoletz Institute of Physiology, Kiev, Ukraine
- Department of Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Chao Liu
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gary B. Braun
- STEMCELL Technologies, Vancouver, British Columbia, Canada
| | | | - Yury I. Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Elena Molokanova
- Nanotools Bioscience, San Diego, CA 92121, USA
- Corresponding author. (E.M.); (A.S.)
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Heselich A, Frieß JL, Ritter S, Benz NP, Layer PG, Thielemann C. High LET radiation shows no major cellular and functional effects on primary cardiomyocytes in vitro. Life Sci Space Res (Amst) 2018; 16:93-100. [PMID: 29475525 DOI: 10.1016/j.lssr.2018.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/18/2017] [Accepted: 01/10/2018] [Indexed: 06/08/2023]
Abstract
It is well known that ionizing radiation causes adverse effects on various mammalian tissues. However, there is little information on the biological effects of heavy ion radiation on the heart. In order to fill this gap, we systematically examined DNA-damage induction and repair, as well as proliferation and apoptosis in avian cardiomyocyte cultures irradiated with heavy ions such as titanium and iron, relevant for manned space-flight, and carbon ions, as used for radiotherapy. Further, and to our knowledge for the first time, we analyzed the effect of heavy ion radiation on the electrophysiology of primary cardiomyocytes derived from chicken embryos using the non-invasive microelectrode array (MEA) technology. As electrophysiological endpoints beat rate and field action potential duration were analyzed. The cultures clearly exhibited the capacity to repair induced DNA damage almost completely within 24 h, even at doses of 7 Gy, and almost completely recovered from radiation-induced changes in proliferative behavior. Interestingly, no significant effects on apoptosis could be detected. Especially the functionality of primary cardiac cells exhibited a surprisingly high robustness against heavy ion radiation, even at doses of up to 7 Gy. In contrast to our previous study with X-rays the beat rate remained more or less unaffected after heavy ion radiation, independently of beam quality. The only change we could observe was an increase of the field action potential duration of up to 30% after titanium irradiation, diminishing within the following three days. This potentially pathological observation may be an indication that heavy ion irradiation at high doses could bear a long-term risk for cardiovascular disease induction.
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Affiliation(s)
- Anja Heselich
- University for Applied Sciences Aschaffenburg, biomems lab, Würzburger Straße 45, Aschaffenburg 63743, Germany; Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, Darmstadt 64287, Germany; GSI Helmholtz Centre for Heavy Ion Research (GSI), Biophysics Department, Planckstraße 1, Darmstadt 64291, Germany
| | - Johannes L Frieß
- University for Applied Sciences Aschaffenburg, biomems lab, Würzburger Straße 45, Aschaffenburg 63743, Germany
| | - Sylvia Ritter
- GSI Helmholtz Centre for Heavy Ion Research (GSI), Biophysics Department, Planckstraße 1, Darmstadt 64291, Germany
| | - Naja P Benz
- Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Paul G Layer
- Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, Darmstadt 64287, Germany
| | - Christiane Thielemann
- University for Applied Sciences Aschaffenburg, biomems lab, Würzburger Straße 45, Aschaffenburg 63743, Germany.
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Horot IV, Tkachenko MM. Peculiarities of ultrastructural organization and metabolism of reactive forms of oxygen and nitrogen in a cardiovascular system for permanent effects of ionizing radiation in low doses. Probl Radiac Med Radiobiol 2017; 22:184-201. [PMID: 29286505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Indexed: 06/07/2023]
Abstract
OBJECTIVE Determination of the peculiarities of ultrastructural changes and metabolism of reactive forms of oxy gen and nitrogen in the tissues of the myocardium, aorta and portal vein of the radiosensitive BALB/c mice due long term exposure to the complex of radionuclides of Chоrnobyl fallout (ejection) and low intensity low dose γ irradiation. MATERIALS AND METHODS Experimental studies were performed on 60 mice female radiosensitive lines BALB/c with a body weight of 20-22 g, which were divided into 3 groups: I group (control) animals age 6-9 months which were born and lived their lives in Kyiv vivarium under conditions natural radioactive background; ІІ - animals age 6 months, which were born and lived in the Chornobyl exclusion zone throughout their lives; ІІІ - animals, which from 3 months of age for 6 months were constantly located in cages with flat ionizing radiation sources and exposed to external γ irradiation in a total dose of 0.43 Sv. Animals of II and III groups were kept in the vivarium of the Institute for Safety Problems of Nuclear Power Plants of the National Academy of Sciences of Ukraine (Chornobyl). Mice of the BALB/c lines are sensitive to radiation: for males LD 50/30 < 5.7 Gy, for females - 5.85 Gy. RESULTS AND CONCLUSIONS The peculiarities of structural and functional changes in the organs of the cardiovascular system (CVS) and mechanisms of the development of oxidative and nitrosatitative stress due long term exposure to the complex of radionuclides of the Chornobyl fallout (ejection) and low intensity low dose γ radiation based on the study of ultrastructural organization and metabolism of reactive oxygen species (ROS) and nitrogen (NRS) of the atri al cardiomyocytes (CMC), the aortic endothelium and portal vein of the BALB/c mice. Found that the permanent expo sure to low doses of radiation changes occur, including the dominant mechanism is to run a CMC apoptosis and endothelial cells of the aorta and portal vein. It is shown that the development of oxidative stress accompanied by increased activity of ROS metabolism that occurs due to activation of nucleotide and lipid superoxide generators. Found that under these conditions the development of nitrosative stress is due to the activation of inducible NO syn thesis enzyme iNOS and inhibit its synthesis constitutive eNOS enzyme. High levels of simultaneous generation of superoxide and NO, bindting, lead to the formation of toxic peroxynitrite, which initiates the process of apoptosis.
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Affiliation(s)
- I V Horot
- Bogomolets National Medical University, T. Shevchenko Boulevard, 13, Kyiv, 01601, Ukraine
| | - M M Tkachenko
- Bogomolets National Medical University, T. Shevchenko Boulevard, 13, Kyiv, 01601, Ukraine
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13
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Watanabe M, Feola I, Majumder R, Jangsangthong W, Teplenin AS, Ypey DL, Schalij MJ, Zeppenfeld K, de Vries AAF, Pijnappels DA. Optogenetic manipulation of anatomical re-entry by light-guided generation of a reversible local conduction block. Cardiovasc Res 2017; 113:354-366. [PMID: 28395022 DOI: 10.1093/cvr/cvx003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 01/10/2017] [Indexed: 01/03/2023] Open
Abstract
Aims Anatomical re-entry is an important mechanism of ventricular tachycardia, characterized by circular electrical propagation in a fixed pathway. It's current investigative and therapeutic approaches are non-biological, rather unspecific (drugs), traumatizing (electrical shocks), or irreversible (ablation). Optogenetics is a new biological technique that allows reversible modulation of electrical function with unmatched spatiotemporal precision using light-gated ion channels. We therefore investigated optogenetic manipulation of anatomical re-entry in ventricular cardiac tissue. Methods and results Transverse, 150-μm-thick ventricular slices, obtained from neonatal rat hearts, were genetically modified with lentiviral vectors encoding Ca2+-translocating channelrhodopsin (CatCh), a light-gated depolarizing ion channel, or enhanced yellow fluorescent protein (eYFP) as control. Stable anatomical re-entry was induced in both experimental groups. Activation of CatCh was precisely controlled by 470-nm patterned illumination, while the effects on anatomical re-entry were studied by optical voltage mapping. Regional illumination in the pathway of anatomical re-entry resulted in termination of arrhythmic activity only in CatCh-expressing slices by establishing a local and reversible, depolarization-induced conduction block in the illuminated area. Systematic adjustment of the size of the light-exposed area in the re-entrant pathway revealed that re-entry could be terminated by either wave collision or extinction, depending on the depth (transmurality) of illumination. In silico studies implicated source-sink mismatches at the site of subtransmural conduction block as an important factor in re-entry termination. Conclusions Anatomical re-entry in ventricular tissue can be manipulated by optogenetic induction of a local and reversible conduction block in the re-entrant pathway, allowing effective re-entry termination. These results provide distinctively new mechanistic insight into re-entry termination and a novel perspective for cardiac arrhythmia management.
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Zhang ZY, Li Y, Li R, Zhang AA, Shang B, Yu J, Xie XD. Tetrahydrobiopterin Protects against Radiation-induced Growth Inhibition in H9c2 Cardiomyocytes. Chin Med J (Engl) 2016; 129:2733-2740. [PMID: 27824007 PMCID: PMC5126166 DOI: 10.4103/0366-6999.193455] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Tetrahydrobiopterin (BH4) is an essential cofactor of nitric oxide synthases (NOSs) for the synthesis of nitric oxide (NO). BH4 therapy can reverse the disease-related redox disequilibrium observed with BH4 deficiency. However, whether BH4 exerts a protective effect against radiation-induced damage to cardiomyocytes remains unknown. METHODS Clonogenic assays were performed to determine the effects of X-ray on H9c2 cells with or without BH4 treatment. The contents of lactate dehydrogenase (LDH), superoxide dismutase (SOD), and malondialdehyde (MDA) in H9c2 cells were measured to investigate oxidative stress levels. The cell cycle undergoing radiation with or without BH4 treatment was detected using flow cytometry. The expression levels of proteins in the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/P53 signaling pathway, inducible NOS (iNOS), and endothelial NOS (eNOS) were examined using Western blotting. RESULTS X-ray radiation significantly inhibited the growth of H9c2 cells in a dose-dependent manner, whereas BH4 treatment significantly reduced the X-ray radiation-induced growth inhibition (control group vs. X-ray groups, respectively, P< 0.01). X-ray radiation induced LDH release, apoptosis, and G0/G1 peak accumulation, significantly increasing the level of MDA and the production of NO, and decreased the level of SOD (control group vs. X-ray groups, respectively, P < 0.05 or P < 0.01). By contrast, BH4 treatment can significantly reverse these processes (BH4 treatment groups vs. X-ray groups, P < 0.05 or P < 0.01). BH4 reversed the X-ray radiation-induced expression alterations of apoptosis-related molecules, including B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein, and caspase-3, and molecules of the PI3K/Akt/P53 signaling pathway. BH4 enhanced the production of NO in 2 Gy and 4 Gy radiated groups by upregulating eNOS protein expression and downregulating iNOS protein expression. CONCLUSIONS BH4 treatment can protect against X-ray-induced cardiomyocyte injury, possibly by recoupling eNOS rather than iNOS. BH4 treatment also decreased oxidative stress in radiated H9c2 cells.
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Affiliation(s)
- Zheng-Yi Zhang
- Department of Hypertension, Lanzhou University Second Hospital, Lanzhou, Gansu 730030, China
- Department of Heart Failure, Lanzhou University Second Hospital, Lanzhou, Gansu 730030, China
| | - Yi Li
- Institute of Medical Genetics, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Rui Li
- School of Stomatology, Lanzhou University, Lanzhou, Gansu 730000, China
| | - An-An Zhang
- Institute of Medical Genetics, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Bo Shang
- Department of Heart Failure, Lanzhou University Second Hospital, Lanzhou, Gansu 730030, China
| | - Jing Yu
- Department of Hypertension, Lanzhou University Second Hospital, Lanzhou, Gansu 730030, China
| | - Xiao-Dong Xie
- Institute of Medical Genetics, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu 730000, China
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Alabovsky VV, Kudryshov YB, Vinokurov AA, Bogacheva EV, Maslov OV, Perov SY. [Radio Frequency Electromagnetic Field Effect on the State of Na+/Ca2+ Exchange in the Isolated Rat Heart]. Radiats Biol Radioecol 2016; 56:171-176. [PMID: 27534068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
It has been shown that a single exposure to 171 MHz electromagnetic field with 180 V/m electric field strength and 0.04 mW/kg specific absorption rate significantly alters the Na+/Ca2+ exchange in the isolated rat heart. It is assumed that enhancement of the Na+/Ca2+ exchange towards removing Ca2+ from the cardiomyocytes electromagnetic field exposure is a result of Ca2+ extraction from the sarcoplasmic reticulum and the increase of its intracellular level.
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16
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Gu A, Jie Y, Sun L, Zhao S, E M, You Q. RhNRG-1β Protects the Myocardium against Irradiation-Induced Damage via the ErbB2-ERK-SIRT1 Signaling Pathway. PLoS One 2015; 10:e0137337. [PMID: 26332771 PMCID: PMC4558028 DOI: 10.1371/journal.pone.0137337] [Citation(s) in RCA: 21] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 08/15/2015] [Indexed: 12/17/2022] Open
Abstract
Radiation-induced heart disease (RIHD), which is a serious side effect of the radiotherapy applied for various tumors due to the inevitable irradiation of the heart, cannot be treated effectively using current clinical therapies. Here, we demonstrated that rhNRG-1β, an epidermal growth factor (EGF)-like protein, protects myocardium tissue against irradiation-induced damage and preserves cardiac function. rhNRG-1β effectively ameliorated irradiation-induced myocardial nuclear damage in both cultured adult rat-derived cardiomyocytes and rat myocardium tissue via NRG/ErbB2 signaling. By activating ErbB2, rhNRG-1β maintained mitochondrial integrity, ATP production, respiratory chain function and the Krebs cycle status in irradiated cardiomyocytes. Moreover, the protection of irradiated cardiomyocytes and myocardium tissue by rhNRG-1β was at least partly mediated by the activation of the ErbB2-ERK-SIRT1 signaling pathway. Long-term observations further showed that rhNRG-1β administered in the peri-irradiation period exerts continuous protective effects on cardiac pump function, the myocardial energy metabolism, cardiomyocyte volume and interstitial fibrosis in the rats receiving radiation via NRG/ErbB2 signaling. Our findings indicate that rhNRG-1β can protect the myocardium against irradiation-induced damage and preserve cardiac function via the ErbB2-ERK-SIRT1 signaling pathway.
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Affiliation(s)
- Anxin Gu
- Department of Radiotherapy, the Affiliated Tumor Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Yamin Jie
- Department of Radiotherapy, the Fourth Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Liang Sun
- Department of Human Anatomy, Harbin Medical University, Harbin, Heilongjiang, China
| | - Shuping Zhao
- Department of Radiotherapy, the Affiliated Tumor Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Mingyan E
- Department of Radiotherapy, the Affiliated Tumor Hospital of Harbin Medical University, Harbin, Heilongjiang, China
- * E-mail: (QY); (ME)
| | - Qingshan You
- Department of Radiotherapy, the Affiliated Tumor Hospital of Harbin Medical University, Harbin, Heilongjiang, China
- * E-mail: (QY); (ME)
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17
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Frieß JL, Heselich A, Ritter S, Haber A, Kaiser N, Layer PG, Thielemann C. Electrophysiologic and cellular characteristics of cardiomyocytes after X-ray irradiation. Mutat Res 2015; 777:1-10. [PMID: 25912077 DOI: 10.1016/j.mrfmmm.2015.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 06/04/2023]
Abstract
The aim of this study was to investigate possible effects of ionizing irradiation on the electrophysiological functionality of cardiac myocytes in vitro. Primary chicken cardiomyocytes with spontaneous beating activity were irradiated with X-rays (dose range of 0.5-7 Gy). Functional alterations of cardiac cell cultures were evaluated up to 7 days after irradiation using microelectrode arrays. As examined endpoints, cell proliferation, apoptosis, reactive oxygen species (ROS) and DNA damage were evaluated. The beat rate of the cardiac networks increased in a dose-dependent manner over one week. The duration of single action potentials was slightly shortened. Additionally, we observed lower numbers of mitotic and S-phase cells at certain time points after irradiation. Also, the number of cells with γH2AX foci increased as a function of the dose. No significant changes in the level of ROS were detected. Induction of apoptosis was generally negligibly low. This is the first report to directly show alterations in cardiac electrophysiology caused by ionizing radiation, which were detectable up to one week after irradiation.
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Affiliation(s)
- Johannes L Frieß
- University for Applied Sciences Aschaffenburg, biomems lab, Würzburger Straße 45, 63743 Aschaffenburg, Germany.
| | - Anja Heselich
- Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, 64287 Darmstadt, Germany
| | - Sylvia Ritter
- Helmholtz Institute for Heavy Ion Research (GSI), Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
| | - Angelina Haber
- Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, 64287 Darmstadt, Germany
| | - Nicole Kaiser
- Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, 64287 Darmstadt, Germany
| | - Paul G Layer
- Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, 64287 Darmstadt, Germany
| | - Christiane Thielemann
- University for Applied Sciences Aschaffenburg, biomems lab, Würzburger Straße 45, 63743 Aschaffenburg, Germany
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Kurotsu M, Ogawa E, Arai T. Conduction block in novel cardiomyocyte electrical conduction line by photosensitization reaction. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2014:4787-90. [PMID: 25571062 DOI: 10.1109/embc.2014.6944694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We developed a novel cardiomyocyte electrical conduction line. We studied electrical conduction block by extra-cellular photosensitization reaction with this conduction line to study electrical blockade by the photosensitization reaction in vitro.
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Bigelow AW, Ponnaiya B, Targoff KL, Brenner DJ. UV microspot irradiator at Columbia University. Radiat Environ Biophys 2013; 52:411-417. [PMID: 23708525 PMCID: PMC3723145 DOI: 10.1007/s00411-013-0474-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 05/13/2013] [Indexed: 06/02/2023]
Abstract
The Radiological Research Accelerator Facility at Columbia University has recently added a UV microspot irradiator to a microbeam irradiation platform. This UV microspot irradiator applies multiphoton excitation at the focal point of an incident laser as the source for cell damage, and with this approach, a single cell within a 3D sample can be targeted and exposed to damaging UV. The UV microspot's ability to impart cellular damage within 3D is an advantage over all other microbeam techniques, which instead impart damage to numerous cells along microbeam tracks. This short communication is an overview, and a description of the UV microspot including the following applications and demonstrations of selective damage to live single cell targets: DNA damage foci formation, patterned irradiation, photoactivation, targeting of mitochondria, and targeting of individual cardiomyocytes in a live zebrafish embryo.
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Affiliation(s)
- Alan W Bigelow
- Center for Radiological Research, Columbia University Medical Center, New York, NY, USA.
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Bittihn P, Hörning M, Luther S. Negative curvature boundaries as wave emitting sites for the control of biological excitable media. Phys Rev Lett 2012; 109:118106. [PMID: 23005683 DOI: 10.1103/physrevlett.109.118106] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Indexed: 06/01/2023]
Abstract
Understanding the interaction of electric fields with the complex anatomy of biological excitable media is key to optimizing control strategies for spatiotemporal dynamics in those systems. On the basis of a bidomain description, we provide a unified theory for the electric-field-induced depolarization of the substrate near curved boundaries of generalized shapes, resulting in the localized recruitment of control sites. Our findings are confirmed in experiments on cardiomyocyte cell cultures and supported by two-dimensional numerical simulations on a cross section of a rabbit ventricle.
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Affiliation(s)
- Philip Bittihn
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.
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21
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Hörning M, Takagi S, Yoshikawa K. Controlling activation site density by low-energy far-field stimulation in cardiac tissue. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 85:061906. [PMID: 23005126 DOI: 10.1103/physreve.85.061906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/19/2012] [Indexed: 06/01/2023]
Abstract
Tachycardia and fibrillation are potentially fatal arrhythmias associated with the formation of rotating spiral waves in the heart. Presently, the termination of these types of arrhythmia is achieved by use of antitachycardia pacing or cardioversion. However, these techniques have serious drawbacks, in that they either have limited application or produce undesirable side effects. Low-energy far-field stimulation has recently been proposed as a superior therapy. This proposed therapeutic method would exploit the phenomenon in which the application of low-energy far-field shocks induces a large number of activation sites ("virtual electrodes") in tissue. It has been found that the formation of such sites can lead to the termination of undesired states in the heart and the restoration of normal beating. In this study we investigate a particular aspect of this method. Here we seek to determine how the activation site density depends on the applied electric field through in vitro experiments carried out on neonatal rat cardiac tissue cultures. The results indicate that the activation site density increases exponentially as a function of the intracellular conductivity and the level of cell isotropy. Additionally, we report numerical results obtained from bidomain simulations of the Beeler-Reuter model that are quantitatively consistent with our experimental results. Also, we derive an intuitive analytical framework that describes the activation site density and provides useful information for determining the ratio of longitudinal to transverse conductivity in a cardiac tissue culture. The results obtained here should be useful in the development of an actual therapeutic method based on low-energy far-field pacing. In addition, they provide a deeper understanding of the intrinsic properties of cardiac cells.
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Affiliation(s)
- Marcel Hörning
- Department of Physics, Graduate School of Science, Kyoto University, Japan.
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Gao S, Wu R, Zeng Y. Up-regulation of peroxisome proliferator-activated receptor gamma in radiation-induced heart injury in rats. Radiat Environ Biophys 2012; 51:53-59. [PMID: 21997460 DOI: 10.1007/s00411-011-0390-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 09/23/2011] [Indexed: 05/31/2023]
Abstract
To explore the expression level and the role of peroxisome proliferator-activated receptor gamma (PPAR-γ) in radiation-induced heart injury in a rat model, thirty-two Sprague-Dawley rats were divided into three groups (the control group, the 15-Gy irradiation group and the 18-Gy irradiation group). Experimental animals were exposed to radiation generated by a linear accelerator at the chest and killed after 3 months. Heart tissues from these animals were removed for Masson staining, PPAR-γ immunohistochemical staining, Western blot analysis and real-time polymerase chain reaction assay (RT-PCR). In addition, the protein expression of matrix metalloprotein-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and transforming growth factor type beta1 (TGF-β1), all of which are associated with fibrosis, was measured. Masson staining revealed significant myocardial fibrosis, degeneration and necrosis in rats exposed to radiation. The results of immunohistochemical staining and Western blot analysis showed that PPAR-γ protein expression in hearts of the irradiation groups was significantly higher than in the control group, especially in myocardium and vascular endothelial (p < 0.05). RT-PCR results also showed a parallel increase in PPAR-γ mRNA expression in the heart of the irradiation groups compared with the control group (p < 0.05). The expression of MMP-1 protein was not significantly different in three groups (p > 0.05). The expression of TIMP-1 and TGF-β1 proteins was, however, higher in two irradiation groups than in the control group (p < 0.05). These data demonstrate that PPAR-γ expression is up-regulated on both mRNA and protein levels in heart injured by radiation. PPAR-γ may play an important role in radiation-induced heart injury.
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Affiliation(s)
- Song Gao
- Department of Clinical Oncology, Shengjing Hospital of China Medical University, 39 Huaxiang Road, Shenyang, 110022, People's Republic of China.
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Feng X, He X, Li K, Wu W, Liu X, Li L. [The effects of pulsed electromagnetic fields on the induction of rat bone marrow mesenchymal stem cells to differentiate into cardiomyocytes-like cells in vitro]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2011; 28:676-682. [PMID: 21936361] [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: 05/31/2023]
Abstract
The aim of this study is to investigate the effects of pulsed electromagnetic fields (PEMFs) on the induction of rat bone marrow mesenchymal stem cells (rBMSCs) to differentiate into cardiomyocytes-like cells in vitro. rBMSCs were randomly divided into PEMFs groups, 5-Azacytidine (5-Aza) groups and control groups. PEMFs groups were exposed to 50 Hz, 1 mT PEMFs for 30 min every day, lasting for 10 d, 15 d and 20 d, respectively. 5-Aza groups were induced by 10 micromol/L 5-Aza for 1 day, then the medium was changed to complete medium without 5-Aza. And control groups were only cultured with complete medium, rBMSCs growth status and morphological features were observed by inverted phase microscope every day. The mRNA expressions of cardiac troponin T (TNNT2) and alpha-actinin (ACTN2) were determined by Real-Time PCR. The results showed that rBMSCs were spindle, polygon or fusiform in control groups. The cells gradually got longer and grew close together after being stimulated by PEMFs and 5-Aza, and with the extension of induction time, the tendency became obvious. At 20th day after PEMFs or 5-Aza treatment, rBMSCs gathered like a long chain, got much longer obviously at the high magnification, and some of them even fused with their neighbors. Compared with control groups, the levels of TNNT2 mRNA expression in 5-Aza groups were 19.40 fold (P < 0.01), 21.02 fold (P < 0.01) and 2.38 fold at 10 d, 15 d, 20 d and the levels of ACTN2 mRNA expression in 5-Aza groups were 6.64 fold (P < 0.01), 6.67 fold (P < 0.01) and 0.76 fold at 10 d, 15 d, 20 d. However, the levels of TNNT2 mRNA expression in PEMFs groups were 15.78 fold (P < 0.01), 6.73 fold (P < 0.05) and 2.73 fold (P < 0.01) of control groups at 10 d, 15 d, 20 d and the levels of ACTN2 mRNA expression in PEMFs groups were 4.93 fold (P < 0.01), 1.89 fold and 0.64 fold, respectively. Compared with 5-Aza groups, the levels of TNNT2 mRNA expression in PEMFs groups were 0.81 fold, 0.32 fold (P < 0.01) and 1.15 fold at 10 d, 15 d, 20 d and the levels of ACTN2 mRNA expression in PEMFs groups were 0.74 fold, 0.28 fold (P < 0.01) and 0.83 fold at 10 d, 15 d, 20 d. PEMFs could contribute to the induction of rat marrow rBMSCs to differentiate into cardiomyocytes-like cells in vitro, and the best exposure time might be 10 days, but further investigation is still needed.
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Affiliation(s)
- Xian Feng
- Institute of Biomedical Engineering, West China College of Preclinical Medicine and Forensic Medicine, Sichuan University, Chengdu 610041, China
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Hofmann B, Maybeck V, Eick S, Meffert S, Ingebrandt S, Wood P, Bamberg E, Offenhäusser A. Light induced stimulation and delay of cardiac activity. Lab Chip 2010; 10:2588-2596. [PMID: 20689860 DOI: 10.1039/c003091k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This article shows the combination of light activatable ion channels and microelectrode array (MEA) technology for bidirectionally interfacing cells. HL-1 cultures, a mouse derived cardiomyocyte-like cell line, transfected with channelrhodopsin were stimulated with a microscope coupled 473 nm laser and recorded with custom built 64 electrode MEAs. Channelrhodopsin induced depolarization of the cell can evoke action potentials (APs) in single cells. Spreading of the AP over the cell layer can then be measured with good spatiotemporal resolution using MEA recordings. The possibility for light induced pacemaker switching in cultures was shown. Furthermore, the suppression of APs can also be achieved with the laser. Possible applications include cell analysis, e.g. pacemaker interference or induced pacemaker switching, and medical applications such as a combined cardiac pacemaker and defibrillator triggered by light. Since current prosthesis research focuses on bidirectionality, this system may be applied to any electrogenic cell, including neurons or muscles, to advance this field.
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Affiliation(s)
- Boris Hofmann
- Institute of Bio- and Nanosystems-Bioelectronics (IBN-2) and Jara-FIT, Forschungszentrum Jülich, Leo-Brandt-Str., D-52425 Jülich, Germany
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25
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Khramov RN, Santalova IM, Fakhranurova LI, Manokhin AA, Simonova NB, Rzhevskiĭ DI, Murashev AN. [The strategy of the "useful sun" improves physical endurance and structural adaptation in the myocardium]. Biofizika 2010; 55:507-513. [PMID: 20586332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The action of solar light transformed by special screens has been studied on CD-1 male mice. In the active control group, mice were irradiated through screens absorbing the UV-component. In the experimental group, screens transforming the UV-component into the orange-red light were used. In the active control, changes in the swimming activity, as compared to the same parameter before irradiation, were manifested much less than in animals of the experimental group. A morphological analysis showed changes in the structure of all cardiomyocyte organelles studied: the relative area of mitochondria in the experimental mice increased by more than 20% compared to intact animals (p < 0.05). A significant increase in the area of the sarcoplasmic reticulum, by 23.4% (p < 0.05), and in the volume of the myofibrillar apparatus, by 19.4% (p < 0.05), was detected. The results of our experiment show that the irradiation with using an additional orange-red component improves the physical endurance 1.5 times and initiates morphogenetic processes in cardiac muscle cells.
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Abstract
The intracellular effects of focused near-infrared femtosecond laser irradiation are shown to cause contraction in cultured neonatal rat cardiomyocytes. By periodic exposure to femtosecond laser pulse-trains, periodic contraction cycles in cardiomyocytes could be triggered, depleted, and synchronized with the laser periodicity. This was observed in isolated cells, and in small groups of cardiomyocytes with the laser acting as pacemaker for the entire group. A window for this effect was found to occur between 15 and 30 mW average power for an 80 fs, 82 MHz pulse train of 780 nm, using 8 ms exposures applied periodically at 1 to 2 Hz. At power levels below this power window, laser-induced cardiomyocyte contraction was not observed, while above this power window, cells typically responded by a high calcium elevation and contracted without subsequent relaxation. This laser-cell interaction allows the laser irradiation to act as a pacemaker, and can be used to trigger contraction in dormant cells as well as synchronize or destabilize contraction in spontaneously contracting cardiomyocytes. By increasing laser power above the window available for laser-cell synchronization, we also demonstrate the use of cardiomyocytes as optically-triggered actuators. To our knowledge, this is the first demonstration of remote optical control of cardiomyocytes without requiring exogenous photosensitive compounds.
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Affiliation(s)
- N I Smith
- Department of Frontier Biosciences, Graduate School of Frontier Biosciences Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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27
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Abstract
Reentrant spiral waves can become pinned to small anatomical obstacles in the heart and lead to monomorphic ventricular tachycardia that can degenerate into polymorphic tachycardia and ventricular fibrillation. Electric field-induced secondary source stimulation can excite directly at the obstacle, and may provide a means to terminate the pinned wave or inhibit the transition to more complex arrhythmia. We used confluent monolayers of neonatal rat ventricular myocytes to investigate the use of low intensity electric field stimulation to perturb the spiral wave. A hole 2-4 mm in diameter was created in the center to pin the spiral wave. Monolayers were stained with voltage-sensitive dye di-4-ANEPPS and mapped at 253 sites. Spiral waves were initiated that attached to the hole (n = 10 monolayers). Electric field pulses 1-s in duration were delivered with increasing strength (0.5-5 V/cm) until the wave terminated after detaching from the hole. At subdetachment intensities, cycle length increased with field strength, was sustained for the duration of the pulse, and returned to its original value after termination of the pulse. Mechanistically, conduction velocity near the wave tip decreased with field strength in the region of depolarization at the obstacle. In summary, electric fields cause strength-dependent slowing or detachment of pinned spiral waves. Our results suggest a means to decelerate tachycardia that may help to prevent wave degeneration.
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Affiliation(s)
- Joshua Cysyk
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland, USA
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28
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Vazan R, Janega P, Hojná S, Zicha J, Simko F, Pechánová O, Styk J, Paulis L. The effect of continuous light exposure of rats on cardiac response to ischemia-reperfusion and NO-synthase activity. Physiol Res 2007; 56 Suppl 2:S63-S69. [PMID: 17824805 DOI: 10.33549/physiolres.931399] [Citation(s) in RCA: 6] [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: 11/25/2022] Open
Abstract
Factors modulating cardiac susceptibility to ischemia-reperfusion (I/R) are permanently attracting the attention of experimental cardiology research. We investigated, whether continuous 24 h/day light exposure of rats can modify cardiac response to I/R, NO-synthase (NOS) activity and the level of oxidative load represented by conjugated dienes (CD) concentration. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light for 4 weeks. Perfused isolated hearts (Langendorff technique) were exposed to 25 min global ischemia and subsequent 30 min reperfusion. The recovery of functional parameters (coronary flow, left ventricular developed pressure, contractility and relaxation index) during reperfusion as well as the incidence, severity and duration of arrhythmias during first 10 min of reperfusion were determined. The hearts from rats exposed to continuous light showed more rapid recovery of functional parameters but higher incidence, duration and severity of reperfusion arrhythmias compared to controls. In the left ventricle, the NOS activity was attenuated, but the CD concentration was not significantly changed. We conclude that the exposure of rats to continuous light modified cardiac response to I/R. This effect could be at least partially mediated by attenuated NO production.
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Affiliation(s)
- R Vazan
- Institute of Pathophysiology, Comenius University, Bratislava, Slovak Republic
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29
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Abstract
BACKGROUND AND OBJECTIVES Low-level laser irradiation (LLLI) was found to promote the proliferation of various types of cells in vitro. Stem cells in general are of significance for implantation in regenerative medicine. The aim of the present study was to investigate the effect of LLLI on the proliferation of mesenchymal stem cells (MSCs) and cardiac stem cells (CSCs). STUDY DESIGN/MATERIALS AND METHODS Isolation of MSCs and CSCs was performed. The cells were cultured and laser irradiation was applied at energy densities of 1 and 3 J/cm2. RESULTS The number of MSCs and CSCs up to 2 and 4 weeks respectively, post-LLLI demonstrated a significant increase in the laser-treated cultures as compared to the control. CONCLUSION The present study clearly demonstrates the ability of LLLI to promote proliferation of MSCs and CSCs in vitro. These results may have an important impact on regenerative medicine.
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Affiliation(s)
- Hana Tuby
- Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
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30
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Heidi Au HT, Cheng I, Chowdhury MF, Radisic M. Interactive effects of surface topography and pulsatile electrical field stimulation on orientation and elongation of fibroblasts and cardiomyocytes. Biomaterials 2007; 28:4277-93. [PMID: 17604100 PMCID: PMC2039774 DOI: 10.1016/j.biomaterials.2007.06.001] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Accepted: 06/05/2007] [Indexed: 10/23/2022]
Abstract
In contractile tissues such as myocardium, functional properties are directly related to the cellular orientation and elongation. Thus, tissue engineering of functional cardiac patches critically depends on our understanding of the interaction between multiple guidance cues such as topographical, adhesive or electrical. The main objective of this study was to determine the interactive effects of contact guidance and electrical field stimulation on elongation and orientation of fibroblasts and cardiomyocytes, major cell populations of the myocardium. Polyvinyl surfaces were abraded using lapping paper with grain size 1-80 microm, resulting in V-shaped abrasions with the average abrasion peak-to-peak width in the range from 3 to 13 microm, and the average depth in the range from 140 to 700 nm (AFM). The surfaces with abrasions 13 microm wide and 700 nm deep, exhibited the strongest effect on neonatal rat cardiomyocyte elongation and orientation as well as statistically significant effect on orientation of fibroblasts, thus they were utilized for electrical field stimulation. Electrical field stimulation was performed using a regime of relevance for heart tissue in vivo as well as for cardiac tissue engineering. Stimulation (square pulses, 1 ms duration, 1 Hz, 2.3 or 4.6 V/cm) was initiated 24 h after cell seeding and maintained for additional 72 h. The cover slips were positioned between the carbon rod electrodes such that the abrasions were either parallel or perpendicular to the field lines. Non-abraded surfaces were utilized as controls. Field stimulation did not affect cell viability. The presence of a well-developed contractile apparatus in neonatal rat cardiomyocytes (staining for cardiac Troponin I and actin filaments) was identified in the groups cultivated on abraded surfaces in the presence of field stimulation. Overall we observed that (i) fibroblast and cardiomyocyte elongation on non-abraded surfaces was significantly enhanced by electrical field stimulation, (ii) electrical field stimulation promoted orientation of fibroblasts in the direction perpendicular to the field lines when the abrasions were also placed perpendicular to the field lines and (iii) topographical cues were a significantly stronger determinant of cardiomyocyte orientation than the electrical field stimulation. The orientation and elongation response of cardiomyocytes was completely abolished by inhibition of actin polymerization (Cytochalasin D) and only partially by inhibition of phosphatidyl-inositol 3 kinase (PI3K) pathway (LY294002).
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Affiliation(s)
| | - Irene Cheng
- Department of Chemical Engineering and Applied Chemistry
| | | | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry
- Institute of Biomaterials and Biomedical Engineering
- Heart & Stroke/Richard Lewar Centre of Excellence
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Abstract
OBJECTIVE The aim of this study was to determine the wavelength dependence of light-induced redox reactions in cells, particularly whether there is any contribution by red wavelengths. An additional aim was to assess the potential of 2,2,6,6-tetramethyl piperidine-N-oxyl (TEMPO) as a tool for measuring these redox reactions. BACKGROUND DATA Visible light has been shown to affect cells, and redox reactions, which have been detected previously using spin traps, have been proposed as a mechanism. However, there is little evidence that red light, which is used in most such experiments, is redox active in cells. METHODS Redox activity was observed by measuring the decay of the electron paramagnetic resonance signal of TEMPO that occurs in the presence of illuminated cells. Color filters were used to generate blue, green, and red light, and the decay resulting from these wavelengths was compared to the decay caused by white light. RESULTS Shorter wavelengths have a considerably stronger effect than longer wavelengths, although red light has some effect. Creation of reactive oxygen species by red light was confirmed with the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). CONCLUSION Red light can induce redox reactions in illuminated cells. However, shorter wavelengths are more efficient in this regard. In addition, TEMPO was found to be a more sensitive probe than DMPO for detecting light-induced cellular redox reactions.
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Affiliation(s)
- Maor Eichler
- Department of Chemistry, Bar-Ilan University, Ramat Gan, Israel
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32
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Zolles G, Klöcker N, Wenzel D, Weisser-Thomas J, Fleischmann BK, Roeper J, Fakler B. Pacemaking by HCN channels requires interaction with phosphoinositides. Neuron 2007; 52:1027-36. [PMID: 17178405 DOI: 10.1016/j.neuron.2006.12.005] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 11/08/2006] [Accepted: 12/05/2006] [Indexed: 01/07/2023]
Abstract
Hyperpolarization-activated, cyclic-nucleotide-gated (HCN) channels mediate the depolarizing cation current (termed I(h) or I(f)) that initiates spontaneous rhythmic activity in heart and brain. This function critically depends on the reliable opening of HCN channels in the subthreshold voltage-range. Here we show that activation of HCN channels at physiologically relevant voltages requires interaction with phosphoinositides such as phosphatidylinositol-4,5-bisphosphate (PIP(2)). PIP(2) acts as a ligand that allosterically opens HCN channels by shifting voltage-dependent channel activation approximately 20 mV toward depolarized potentials. Allosteric gating by PIP(2) occurs in all HCN subtypes and is independent of the action of cyclic nucleotides. In CNS neurons and cardiomyocytes, enzymatic degradation of phospholipids results in reduced channel activation and slowing of the spontaneous firing rate. These results demonstrate that gating by phospholipids is essential for the pacemaking activity of HCN channels in cardiac and neuronal rhythmogenesis.
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Affiliation(s)
- Gerd Zolles
- Institute of Physiology, University of Freiburg, Hermann-Herder-Strasse 7, 79104 Freiburg, Germany
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33
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Paulis L, Vazan R, Simko F, Pechánová O, Styk J, Babál P, Janega P. Morphological alterations and NO-synthase expression in the heart after continuous light exposure of rats. Physiol Res 2007; 56 Suppl 2:S71-S76. [PMID: 17824804 DOI: 10.33549/physiolres.931400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Although exposure to continuous light is associated with hypertension and modulates the outcome of ischemia-reperfusion injury, less attention has been paid to its effects on cardiac morphology. We investigated whether 4-week exposure of experimental rats to continuous 24 h/day light can modify cardiac morphology, with focus on heart weight, fibrosis and collagen I/III ratio in correlation with NO-synthase expression. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light. After 4 weeks of treatment the absolute and the relative heart weights were determined and myocardial fibrosis and collagen type I/III ratio were evaluated using picrosirius red staining. Endothelial and inducible NO-synthase expression was detected immunohistochemically. The exposure of rats to continuous light resulted in an increase of body weight with proportionally increased heart weight. Myocardial fibrosis remained unaffected but collagen I/III ratio increased. Neither endothelial nor inducible NO-synthase expression was altered in light-exposed rats. We conclude that the loss of structural homogeneity of the myocardium in favor of collagen type I might increase myocardial stiffness and contribute to functional alterations after continuous light exposure.
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Affiliation(s)
- L Paulis
- Institute of Pathophysiology, School of Medicine, Comenius University, Bratislava, Slovak Republic.
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34
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Abstract
It has been reported that magnetic fields with flux densities ranging from microT to mT are able to induce heat shock factor, HSP72 mRNA or heat shock proteins in various cells. In this study we investigated changes in the HSP72 mRNA transcription level in three cell lines (HL-60, H9c2, and Girardi heart cells) and in the intracellular HSP72 protein content in two cell lines (HL-60 and Girardi heart cells) after treatment schemes using electromagnetic fields with a flux density of 2 microT to 4 mT, a frequency of 50 Hz and exposure times from 15 to 30 min. None of the treatments or modalities showed any significant effect on the HSP72 protein level, although HSP72 mRNA could be induced, at least to some extent, with one of the parameter combinations in all cell lines tested. Obviously, HSP72 mRNA transcription and translation are not necessarily coupled in certain cells. This leads to the conclusion that electromagnetic field effects on HSP72 mRNA levels are not indicative for downstream effects unless increased mRNA levels can be correlated with increased HSP72 protein levels as well.
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Affiliation(s)
- Eric Gottwald
- Forschungszentrum Karlsruhe, Institut für Biologische Grenzflächen, Eggenstein-Leopoldshafen, Germany.
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35
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Abstract
Combined radiotherapy and chemotherapy have represented major advance in the therapeutic management of cancer therapy. Anthracycline antineoplastic agents are limited by a high incidence of severe and usually irreversible cardiac toxicity, the cause of which remains controversial. When the primary cardiomyocytes isolated from neonatal rats were preirradiated by gamma-ray, the cells were highly resistant to adriamycin-induced apoptosis. This study shows that irradiation inhibited apoptosis by enhancing Bcl-2, attenuating Bax induction, and preventing collapse of mitochondrial membrane potential (delta psi), cytochrome c release into cytoplasm and caspase-3, -6 and -9 activations. In addition, the preirradiation stimulated the activity of manganese-superoxide dismutase (Mn-SOD) and the expression of Mn-SOD mRNA and protein. Adriamycin decreased Mn-SOD activity but did not change the activity of copper/zinc (Cu/Zn)-SOD under either pre- or nonirradiated condition. Phosphothioate-linked antisense against Mn-SOD, which specifically knocked down the activity of Mn-SOD but not that of Cu/Zn-SOD, reversed irradiation-induced protective effect in adriamycin-exposed cardiomyocytes. These data suggest that the irradiation-induced expression of Mn-SOD plays an important role in irradiation-mediated protection in adriamycin-exposed rat ventricular cardiomyocytes.
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MESH Headings
- Animals
- Animals, Newborn
- Antibiotics, Antineoplastic/pharmacology
- Apoptosis/radiation effects
- Caspase 3
- Caspase Inhibitors
- Cell Culture Techniques
- Cytochromes c/metabolism
- Dose-Response Relationship, Drug
- Doxorubicin/pharmacology
- Gamma Rays
- Heart Ventricles
- Membrane Potentials/drug effects
- Mitochondria, Heart/drug effects
- Mitochondria, Heart/physiology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/radiation effects
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Messenger/biosynthesis
- Radiation Protection
- Rats
- Rats, Wistar
- Reactive Oxygen Species/metabolism
- Superoxide Dismutase/biosynthesis
- Superoxide Dismutase/genetics
- Superoxide Dismutase/metabolism
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Affiliation(s)
- Han-Jung Chae
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Jeonju, Republic of Korea
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36
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Deng H, Song ZJ, Wang DW, Yang H, Ma CQ, Lu YK. [Study on the membrane protein conformational changes and mechanisms of myocardial cell irradiated by pulse microwave]. Guang Pu Xue Yu Guang Pu Fen Xi 2006; 26:1437-40. [PMID: 17058940] [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: 05/12/2023]
Abstract
Micro-Fourier transform infrared spectroscopy (FTIR) technique was applied to study the membrane protein conformational and functional changes of myocardial cell irradiated by pulse microwave. The results show that pulse microwave could influence the membrane protein structure markedly. The stretching vibration of lipid--CH2--, lecithoid C=O, amide I and II region was decreased or displaced. The secondary structures of membrane protein were also changed by irradiation. The percentage of alpha-helix and beta-pleated sheet structure decreased remarkably, and the disordering of secondary membrane proteins increased. All the above changes are correlated with the irradiation dosage. The results indicated that the integrality of myocardial cell membrane was injured by pulse microwave, and the membrane fluidity and stability decreased. Multi-biochemically active structures were damaged. Then all the changes could make a biochemical foundation of pathologic effects, which included membrane function decline, cell morphological change, configuration injuring and apoptosis etc. This paper is from a new view of protein conformation to explore the molecular pathologic mechanism of the damage caused by pulse microwave irradiation.
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Affiliation(s)
- Hua Deng
- College of Life Science, Foshan Science Technology University, Foshan 528231, China
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37
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La C, You Y, Zhabyeyev P, Pelzer DJ, McDonald TF. Ultraviolet photoalteration of late Na+ current in guinea-pig ventricular myocytes. J Membr Biol 2006; 210:43-50. [PMID: 16783617 DOI: 10.1007/s00232-005-0844-6] [Citation(s) in RCA: 7] [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] [Received: 08/02/2005] [Revised: 01/10/2006] [Indexed: 10/24/2022]
Abstract
UV irradiation has multiple effects on mammalian cells, including modification of ion channel function. The present study was undertaken to investigate the response of membrane currents in guinea-pig ventricular myocytes to the type A (355, 380 nm) irradiation commonly used in Ca(2+) imaging studies. Myocytes configured for whole-cell voltage clamp were generally held at -80 mV, dialyzed with K(+)-, Na(+)-free pipette solution, and bathed with K(+)-free Tyrode's solution at 22 degrees C. During experiments that lasted for approximately 35 min, UVA irradiation caused a progressive increase in slowly-inactivating inward current elicited by 200-ms depolarizations from -80 to -40 mV, but had little effect on background current or on L-type Ca(2+) current. Trials with depolarized holding potential, Ca(2+) channel blockers, and tetrodotoxin (TTX) established that the current induced by irradiation was late (slowly-inactivating) Na(+) current (I(Na)). The amplitude of the late inward current sensitive to 100 microM: TTX was increased by 3.5-fold after 20-30 min of irradiation. UVA modulation of late I(Na) may (i) interfere with imaging studies, and (ii) provide a paradigm for investigation of intracellular factors likely to influence slow inactivation of cardiac I(Na).
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Affiliation(s)
- C La
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, B3H 4H7 Canada
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38
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Green AC, Scott IR, Gwyther RJ, Peyman A, Chadwick P, Chen X, Alfadhl Y, Tattersall JEH. An investigation of the effects of TETRA RF fields on intracellular calcium in neurones and cardiac myocytes. Int J Radiat Biol 2006; 81:869-85. [PMID: 16524843 DOI: 10.1080/09553000600555389] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE This study aimed to determine whether Terrestrial Trunked Radio (TETRA) fields can affect intracellular calcium signalling in excitable cells. MATERIALS AND METHODS Intracellular calcium concentration ([Ca(2 +) ](i)) was measured in cultured rat cerebellar granule cells and cardiac myocytes during exposure to TETRA fields (380.8875 MHz pulse modulated at 17.6 Hz, 25% duty cycle). [Ca(2 +) ](i) was measured as fura-PE3, fluo-3 or fluo-4 fluorescence by digital image analysis. RESULTS Granule cells exposed at specific absorption rates (SARs) of 5, 10, 20, 50 or 400 mW x kg(-1) showed no significant changes in resting [Ca(2 +) ](i). Increases in [Ca(2 +) ](i) in response to potassium-induced depolarization were significantly different from sham controls in TETRA-exposed cells, but the majority of the difference was attributable to initial biological variation between cell cultures. No difference was found between fura-PE3 (UV excitation) and fluo-3 (visible light excitation) measurements in these cells. Exposure to TETRA (50 or 400 mW x kg(-1)) had no significant effect on either the rate or amplitude of spontaneous Ca(2 +) transients in cardiac myocytes. The cells showed normal responses to salbutamol (50 microM) and acetylcholine (10 microM). CONCLUSIONS Overall, these results showed no evidence of any consistent or biologically relevant effect of TETRA fields on [Ca(2 + )](i) in granule cells and cardiac myocytes at any of the SAR tested.
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Affiliation(s)
- A C Green
- Biomedical Sciences Department, Dstl Porton Down, Salisbury, UK
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39
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Momotake A, Lindegger N, Niggli E, Barsotti RJ, Ellis-Davies GCR. The nitrodibenzofuran chromophore: a new caging group for ultra-efficient photolysis in living cells. Nat Methods 2005; 3:35-40. [PMID: 16369551 DOI: 10.1038/nmeth821] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Accepted: 10/28/2005] [Indexed: 11/08/2022]
Abstract
Photochemical uncaging of bio-active molecules was introduced in 1977, but since then, there has been no substantial improvement in the properties of generic caging chromophores. We have developed a new chromophore, nitrodibenzofuran (NDBF) for ultra-efficient uncaging of second messengers inside cells. Photolysis of a NDBF derivative of EGTA (caged calcium) is about 16-160 times more efficient than photolysis of the most widely used caged compounds (the quantum yield of photolysis is 0.7 and the extinction coefficient is 18,400 M(-1) cm(-1)). Ultraviolet (UV)-laser photolysis of NDBF-EGTA:Ca(2+) rapidly released Ca(2+) (rate of 20,000 s(-1)) and initiated contraction of skinned guinea pig cardiac muscle. NDBF-EGTA has a two-photon cross-section of approximately 0.6 GM and two-photon photolysis induced localized Ca(2+)-induced Ca(2+) release from the sarcoplasmic recticulum of intact cardiac myocytes. Thus, the NDBF chromophore has great promise as a generic and photochemically efficient protecting group for both one- and two-photon uncaging in living cells.
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Affiliation(s)
- Atsuya Momotake
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 North 15th St., Philadelphia, Pennsylvania 19102, USA
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40
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Deng H, Wang D, Peng R, Wang S, Chen J, Zhang S, Dong B, Wang X. [The electroporation effects of high power pulse microwave and electromagnetic pulse irradiation on the membranes of cardiomyocyte cells and the mechanism therein involved]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2005; 22:672-6, 694. [PMID: 16156247] [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: 05/04/2023]
Abstract
Though there is ongoing public concern on potential hazards and risk of electromagnetic radiation, the bioeffects mechanism of electromagnetic fields remains obscure. Heart is one of the organs susceptive to electromagnetic fields (EMF). This study was designed to assess the influence of high power pulse microwave and electromagnetic pulse irradiation on cardiomyocytes, to explore the critical mechanism of electromagnetic fields, and to explain the regular course of injury caused by exposure to pulse EMF. Cultured cardiomyocytes were irradiated by high power pulse microwave and electromagnetic pulse first, then a series of apparatus including atom force microscope, laser scanning confocal microscope and flow cytometer were used to examine the changes of cell membrane conformation, structure and function. After irradiation, the cardiomyocytes pulsated slower or stop, the cells conformation was abnormal, the cells viability declined, and the percentage of apoptosis and necrosis increased significantly (P< 0.01). The cell membrane had pores unequal in size, and lost its penetration character. The concentration of Na+, K+, Ca2+, Cl-, Mg2+, Ca2+ and P3+ in cell culture medium increased significantly (P< 0.01). and the concentration of Ca2+ in cells ([Ca2+]i) decreased significantly (P<0.01). The results indicated that cardiomyocytes are susceptible to non-ionizing radiation. Pulse electromagnetic field can induce cardiomyocytes electroporation, and can do great damage to cells conformation, structure and function. Electroporation is one of the most critical mechanisms to explain the athermal effects of electromagnetic radiation.
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Affiliation(s)
- Hua Deng
- Foshan Science Technology University, Foshan 528231, China.
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Pan MH, Peng RY, Gao YB, Wang SM, Ma JJ, Wang DW, Hu WH, Su ZT, Yang GS. [Changes of the expression of beta1-adrenergic receptor and M2-muscarinic acetylcholine receptor in rat hearts after high power microwave radiation]. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2005; 23:172-4. [PMID: 16124889] [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: 05/04/2023]
Abstract
OBJECTIVE To investigate the effect of high power microwave (HPM) radiation on the expression of beta(1)-adrenergic receptor (beta(1)-AR) and M(2)-muscarinic acetylcholine receptor (M(2)-AchR) in cardiomyocytes. METHODS S-band HPM device of mean power density 2 approximately 90 mW/cm(2) was used to irradiate 150 healthy Wistar male rats. Immunohistochemistry and image analysis were used to study the pathological characteristics of heart tissue and the expression of beta(1)-AR and M(2)-AchR. RESULTS Radiation of over 10 mW/cm(2) made myocardial fibers disordered in arrangement, degeneration even sarcoplasm condensation, Pace cells necrosis, and Purkinje cells lysis in a dose-dependent manner (r = 0.968, P < 0.05). beta(1)-AR expression in endocardium, membrane and cytoplasm of myocardium of left ventricle was increased on d1 after radiation, peaked on d3 (P < 0.05) and recovered on d14. M(2)-AchR expression was peaked on d1 (P < 0.01) and recovered on d14. CONCLUSION Certain degree intensity of HPM radiation may cause heart injury, and increased expressions of beta(1)-AR and M(2)-AchR, which may play an important role in the pathophysiology of heart injury induced by HPM.
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Affiliation(s)
- Min-hong Pan
- Institute of Radiation Medicine, Academy of Military Medical Sciences, Beijing 100850, China
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42
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Boerma M, van der Wees CGC, Vrieling H, Svensson JP, Wondergem J, van der Laarse A, Mullenders LHF, van Zeeland AA. Microarray analysis of gene expression profiles of cardiac myocytes and fibroblasts after mechanical stress, ionising or ultraviolet radiation. BMC Genomics 2005; 6:6. [PMID: 15656902 PMCID: PMC548301 DOI: 10.1186/1471-2164-6-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Accepted: 01/18/2005] [Indexed: 12/17/2022] Open
Abstract
Background During excessive pressure or volume overload, cardiac cells are subjected to increased mechanical stress (MS). We set out to investigate how the stress response of cardiac cells to MS can be compared to genotoxic stresses induced by DNA damaging agents. We chose for this purpose to use ionising radiation (IR), which during mediastinal radiotherapy can result in cardiac tissue remodelling and diminished heart function, and ultraviolet radiation (UV) that in contrast to IR induces high concentrations of DNA replication- and transcription-blocking lesions. Results Cultures enriched for neonatal rat cardiac myocytes (CM) or fibroblasts were subjected to any one of the three stressors. Affymetrix microarrays, analysed with Linear Modelling on Probe Level, were used to determine gene expression patterns at 24 hours after (the start of) treatment. The numbers of differentially expressed genes after UV were considerably higher than after IR or MS. Remarkably, after all three stressors the predominant gene expression response in CM-enriched fractions was up-regulation, while in fibroblasts genes were more frequently down-regulated. To investigate the activation or repression of specific cellular pathways, genes present on the array were assigned to 25 groups, based on their biological function. As an example, in the group of cholesterol biosynthesis a significant proportion of genes was up-regulated in CM-enriched fractions after MS, but down-regulated after IR or UV. Conclusion Gene expression responses after the types of cellular stress investigated (MS, IR or UV) have a high stressor and cell type specificity.
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Affiliation(s)
- Marjan Boerma
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
- Department of Clinical Oncology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Caroline GC van der Wees
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
- Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Harry Vrieling
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
| | - J Peter Svensson
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
| | - Jan Wondergem
- Department of Clinical Oncology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Arnoud van der Laarse
- Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Leon HF Mullenders
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
| | - Albert A van Zeeland
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
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Keller M, Pignier C, Niggli E, Egger M. Mechanisms of Na+-Ca2+ exchange inhibition by amphiphiles in cardiac myocytes: importance of transbilayer movement. J Membr Biol 2005; 198:159-75. [PMID: 15216417 DOI: 10.1007/s00232-004-0668-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2003] [Revised: 03/01/2004] [Indexed: 10/26/2022]
Abstract
The membrane lipid environment and lipid signaling pathways are potentially involved in the modulation of the activity of the cardiac Na(+)-Ca(2+) exchanger (NCX). In the present study biophysical mechanisms of interactions of amphiphiles with the NCX and the functional consequences were examined. For this purpose, intracellular Ca(2+) concentration jumps were generated by laser-flash photolysis of caged Ca(2+) in guinea-pig ventricular myocytes and Na(+)-Ca(2+) exchange currents ( I(Na/Ca)) were recorded in the whole-cell configuration of the patch-clamp technique. The inhibitory effect of amphiphiles increased with the length of the aliphatic chain between C(7) and C(10) and was more potent with cationic or anionic head groups than with uncharged head groups. Long-chain cationic amines (C(12)) exhibited a cut-off in their efficacy in I(Na/Ca) inhibition. Analysis of the time-course, comparison with the Ni(2+)-induced I(Na/Ca) block and confocal laser scanning microscopy experiments with fluorescent lipid analogs (C(6)- and C(12)-NBD-labeled analogs) suggested that amphiphiles need to be incorporated into the membrane. Furthermore, NCX block appears to require transbilayer movement of the amphiphile to the inner leaflet ("flip"). We conclude that both, hydrophobic and electrostatic interactions between the lipids and the NCX may be important factors for the modulation by lipids and could be relevant in cardiac diseases where the lipid metabolism is altered.
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Affiliation(s)
- M Keller
- Department of Physiology, University of Bern, CH-3012, Bern, Switzerland
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Abstract
BACKGROUND AND OBJECTIVES Damage to blood and other tissues during laser interventions depends mainly upon absorption of laser radiation by cells. The objective of this work was to evaluate the influence tissue-specific physiological factors on photo-damage thresholds of individual cells: Red blood cells (blood), hepatocytes (liver), and miocytes (heart). STUDY DESIGN/MATERIALS AND METHODS Laser-induced damage to individual cells was detected and studied with Laser Load Test (LLT). Probability and thresholds of RBC damage after one laser pulse (532 nm, 10 nanoseconds) were obtained experimentally as functions of physiological conditions. Using in vitro models, we have studied influence of the oxygen level, pH, temperature, and cell heterogeneity on RBC, the inhibition of metabolic activity on miocytes and drug toxicity on hepatocytes. RESULTS Single laser pulse induced cell lyses through a vapor bubble. The decrease of the O2 level and temperature caused increase of damage thresholds at 532 nm. Deviation of the pH level from neutral to any side caused also the increase of the damage threshold. Inhibition of metabolism of miocytes and toxic damage to hepatocytes also resulted in the increase of the damage threshold. CONCLUSIONS Resistance of various tissues at cell level against photo-damage significantly depends on physiological properties of cells. A general rule for such dependence is that the better the cell state the lower its threshold for laser-damage.
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Affiliation(s)
- Dmitri O Lapotko
- International Center, Luikov Heat and Mass Transfer Institute, Minsk, 220072, Belarus.
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45
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Abstract
One of the biggest problems of heart failure is the heart's inability to effectively pump blood to meet the body's demands, which may be caused by disease-induced alterations in contraction properties (such as contractile force and Young's modulus). Thus, it is very important to measure contractile properties at single cardiac myocyte level that can lay the foundation for quantitatively understanding the mechanism of heart failure and understanding molecular alterations in diseased heart cells. In this article, we report a novel single cardiac myocyte contractile force measurement technique based on moving a magnetic bead. The measuring system is mainly composed of 1), a high-power inverted microscope with video output and edge detection; and 2), a moving magnetic bead based magnetic force loading module. The main measurement procedures are as follows: 1), record maximal displacement of single cardiac myocyte during contraction; 2), attach a magnetic bead on one end of the myocyte that will move with myocyte during the contraction; 3), repeat step 1 and record contraction processes under different magnitudes of magnetic force loading by adjusting the magnetic field applied on the magnetic bead; and 4), derive the myocyte contractile force base on the maximal displacement of cell contraction and magnetic loading force. The major advantages of this unique approach are: 1), measuring the force without direct connections to the cell specimen (i.e., "remote sensing", a noninvasive/minimally invasive approach); 2), high sensitivity and large dynamic range (force measurement range: from pico Newton to micro Newton); 3), a convenient and cost-effective approach; and 4), more importantly, it can be used to study the contractile properties of heart cells under different levels of external loading forces by adjusting the magnitude of applied magnetic field, which is very important for studying disease induced alterations in contraction properties. Experimental results demonstrated the feasibility of proposed approach.
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Affiliation(s)
- Shizhuo Yin
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA.
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Ventura C, Maioli M, Asara Y, Santoni D, Mesirca P, Remondini D, Bersani F. Turning on stem cell cardiogenesis with extremely low frequency magnetic fields. FASEB J 2004; 19:155-7. [PMID: 15507470 DOI: 10.1096/fj.04-2695fje] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Modulation of stem cell differentiation is an important assignment for cellular engineering. Embryonic stem (ES) cells can differentiate into cardiomyocytes, but the efficiency is typically low. Here, we show that exposure of mouse ES cells to extremely low frequency magnetic fields triggered the expression of GATA-4 and Nkx-2.5, acting as cardiac lineage-promoting genes in different animal species, including humans. Magnetic fields also enhanced prodynorphin gene expression, and the synthesis and secretion of dynorphin B, an endorphin playing a major role in cardiogenesis. These effects occurred at the transcriptional level and ultimately ensued into a remarkable increase in the yield of ES-derived cardiomyocytes. These results demonstrate the potential use of magnetic fields for modifying the gene program of cardiac differentiation in ES cells without the aid of gene transfer technologies and may pave the way for novel approaches in tissue engineering and cell therapy.
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Affiliation(s)
- Carlo Ventura
- Laboratory of Molecular Biology and Stem Cell Engineering, National Institute of Biostructures and Biosystems, University of Bologna, Bologna, Italy.
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van Brakel TJ, Bolotin G, Salleng KJ, Nifong LW, Allessie MA, Chitwood WR, Maessen JG. Evaluation of Epicardial Microwave Ablation Lesions: Histology Versus Electrophysiology. Ann Thorac Surg 2004; 78:1397-402; discussion 1397-402. [PMID: 15464504 DOI: 10.1016/j.athoracsur.2004.04.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/01/2004] [Indexed: 11/30/2022]
Abstract
BACKGROUND Pulmonary vein isolation is a hallmark in current surgical ablation for atrial fibrillation. However, validation of isolation remains cumbersome. We evaluated electrophysiologic and not histologic means to test isolation. METHODS In 16 mongrel dogs, robot-assisted epicardial beating-heart microwave ablation (FLEX 10) was performed around the pulmonary veins. Electrophysiologic isolation was tested by pacing at 4 times threshold values inside and outside the pulmonary veins (exit and entrance block). The histology of lesions was studied for transmurality and continuity of the lesion lines. In 5 dogs, lesions were studied at various time intervals. RESULTS Histologic evaluation of the lesions showed incomplete (48% +/- 20%) circumferential myocardial damage in all dogs with acute lesions. Electrophysiologic evaluation showed completion of the box (entrance and exit block) in 8 dogs and in another 5 dogs after repeated ablation (p < 0.01 compared with histologic evaluation). Electrophysiologic evaluation of the dogs with chronic lesions showed completed lesions in 4 of 5 dogs directly after ablation. At follow-up (1 to 3 weeks), the isolations remained electrophysiologically complete. Histologic evaluation of the lesions 1 to 3 weeks after ablation showed complete (100%) circumferential lesions in all 4 dogs (p < 0.001 compared with the histology of dogs with acute lesions). CONCLUSIONS Directly after treatment, ablation lesions are best evaluated electrophysiologically, because complete (transmural and circumferential) lesions are not shown by histologic evaluation in the acute stage. After 1 to 3 weeks, the histology is in accordance with the electrophysiology. To obtain a complete isolation, online electrophysiologic evaluation during pulmonary vein microwave ablation is necessary to optimize the results.
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Affiliation(s)
- Thomas J van Brakel
- Department of Cardiothoracic Surgery and Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
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Abstract
In cardiac muscle Ca2+-induced Ca2+ release (CICR) from the sarcoplasmic reticulum (SR) is initiated by Ca2+ influx via L-type Ca2+ channels. At present, the mechanisms underlying termination of SR Ca2+ release, which are required to ensure stable excitation-contraction coupling cycles, are not precisely known. However, the same mechanism leading to refractoriness of SR Ca2+ release could also be responsible for the termination of CICR. To examine the refractoriness of SR Ca2+ release, we analyzed Na+-Ca2+ exchange currents reflecting cytosolic Ca2+ signals induced by UV-laser flash-photolysis of caged Ca2+. Pairs of UV flashes were applied at various intervals to examine the time course of recovery from CICR refractoriness. In cardiomyocytes isolated from guinea-pigs and mice, beta-adrenergic stimulation with isoproterenol-accelerated recovery from refractoriness by approximately 2-fold. Application of cyclopiazonic acid at moderate concentrations (<10 micromol/L) slowed down recovery from refractoriness in a dose-dependent manner. Compared with cells from wild-type littermates, those from phospholamban knockout (PLB-KO) mice exhibited almost 5-fold accelerated recovery from refractoriness. Our results suggest that SR Ca2+ refilling mediated by the SR Ca2+-pump corresponds to the rate-limiting step for recovery from CICR refractoriness. Thus, the Ca2+ sensitivity of CICR appears to be regulated by SR Ca2+ content, possibly resulting from a change in the steady-state Ca2+ sensitivity and in the gating kinetics of the SR Ca2+ release channels (ryanodine receptors). During Ca2+ release, the concomitant reduction in Ca2+ sensitivity of the ryanodine receptors might also underlie Ca2+ spark termination by deactivation.
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Affiliation(s)
- Peter Szentesi
- Department of Physiology, University of Bern, Bern, Switzerland
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49
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Abstract
Mitochondrial permeability transition (mPT) is a crucial event in the progression to cell death in the setting of ischemia-reperfusion. We have used a model system in which mPT can be reliably and reproducibly induced to test the hypothesis that the profound protection associated with the phenomenon of myocardial preconditioning is mediated by suppression of the mPT. Adult rat myocytes were loaded with the fluorescent probe tetramethylrhodamine methyl ester, which generates oxidative stress on laser illumination, thus inducing the mPT (indicated by collapse of the mitochondrial membrane potential) and ATP depletion, seen as rigor contracture. The known inhibitors of the mPT, cyclosporin A (0.2 microM) and N-methyl-4-valine-cyclosporin A (0.4 microM), increased the time taken to induce the mPT by 1.8- and 2.9-fold, respectively, compared with control (P < 0.001) and rigor contracture by 1.5-fold compared with control (P < 0.001). Hypoxic preconditioning (HP) and pharmacological preconditioning, using diazoxide (30 microM) or nicorandil (100 microM), also increased the time taken to induce the mPT by 2.0-, 2.1-, and 1.5-fold, respectively (P < 0.001), and rigor contracture by 1.9-, 1.7-, and 1.5-fold, respectively, compared with control (P < 0.001). Effects of HP, diazoxide, and nicorandil were abolished in the presence of mitochondrial ATP-sensitive K(+) (K(ATP)) channel blockers glibenclamide (10 microM) and 5-hydroxydecanoate (100 microM) but were maintained in the presence of the sarcolemmal K(ATP) channel blocker HMR-1098 (10 microM). In conclusion, preconditioning protects the myocardium by reducing the probability of the mPT, which normally occurs during ischemia-reperfusion in response to oxidative stress.
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Affiliation(s)
- Derek J Hausenloy
- The Hatter Institute and Centre for Cardiology, University College London Hospitals and Medical School, Grafton Way, London WC1E 6DB, UK
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Soeller C, Jacobs MD, Jones KT, Ellis-Davies GCR, Donaldson PJ, Cannell MB. Application of two-photon flash photolysis to reveal intercellular communication and intracellular Ca2+ movements. J Biomed Opt 2003; 8:418-427. [PMID: 12880347 DOI: 10.1117/1.1582468] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Two-photon excitation makes it possible to excite molecules in volumes of much less than 1 fl. In two-photon flash photolysis (TPFP) this property is used to release effector molecules from caged precursors with high three-dimensional resolution. We describe and examine the benefits of using TPFP in model solutions and in a number of cell systems to study their spatial and temporal properties. Using TPFP of caged fluorescein, we determined the free diffusion coefficient of fluorescein (D=4 x 0(-6) cm(2)/s at 20 degrees C, which is in close agreement with published values). TPFP of caged fluorescein in lens tissue in situ revealed spatial nonuniformities in intercellular fiber cell coupling by gap junctions. At the lens periphery, intercellular transport was predominantly directed along rows of cells, but was nearly isotropic further from the periphery. To test an algorithm aiming to reconstruct the Ca(2+) release flux underlying physiological Ca(2+) signals in heart muscle cells, TPFP of DM-Nitrophen was utilized to generate artificial microscopic Ca(2+) signals with known underlying Ca(2+) release flux. In an experiment with mouse oocytes, the recently developed Ca(2+) cage dimethoxynitrophenyl-ethyleneglycol-bis-(beta-aminoethylether)-N,N,N('),N(') tetraacetic acid-4 (DMNPE-4) was released in the oocyte cytosol and inside a nucleolus. Analysis of the resulting fluorescence changes suggested that the effective diffusion coefficient within the nucleolus was half of that in the cytosol. These experiments demonstrate the utility of TPFP as a novel tool for the optical study of biomedical systems.
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Affiliation(s)
- C Soeller
- University of Auckland, School of Medical and Health Sciences, Department of Physiology, Private Bag 92019, Auckland, New Zealand.
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