1
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Herut B, Goldman R, Ozer T, Lazar A, Biton E, Gertman I, Silverman J, Segal Y, Sisma-Ventura G, Gertner Y, Rubin-Blum M, Belkin N, Rahav E. Tar pollution event (2021) at the Southeastern Levantine oligotrophic basin, short-term impacts and operational oceanography perspectives. Mar Pollut Bull 2024; 198:115892. [PMID: 38086105 DOI: 10.1016/j.marpolbul.2023.115892] [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] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/24/2023] [Accepted: 12/02/2023] [Indexed: 01/05/2024]
Abstract
The Levantine basin (LB) in the Southeastern Mediterranean Sea is a high-risk oil pollution hot spot owing to its dense maritime traffic and intense oil and gas exploration and exploitation activities. In February 2021 the Israeli LB shorelines were impacted by an exceptional tar pollution event (~550 tons; average distribution: ~3 kg tar m-1 front beach) of an unknown oil spill source. Here we report on the immediate numerical modelling assessment of the oil spill propagation and tar distribution; operational use of underwater gliders for tracking water column anomalies of dissolved polycyclic aromatic hydrocarbons (PAHs) and turbidity signals; the beached tar composition and amounts and the short-term response of the microbial population along the ~180 km shoreline. This pollution event emphasizes the need for improving the early warning systems for oil spills and implementing continuous operational monitoring at high-risk, ecologically sensitive and valuable resource areas like the Israeli LB waters.
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Affiliation(s)
- B Herut
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel.
| | - R Goldman
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - T Ozer
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - A Lazar
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - E Biton
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - I Gertman
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - J Silverman
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - Y Segal
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - G Sisma-Ventura
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - Y Gertner
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - M Rubin-Blum
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - N Belkin
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
| | - E Rahav
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, Haifa 310800, Israel
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2
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Adolf J, Segal Y, Turna M, Nováková T, Doležal J, Kutílek P, Hejda J, Hadar O, Lhotská L. Evaluation of functional tests performance using a camera-based and machine learning approach. PLoS One 2023; 18:e0288279. [PMID: 37922293 PMCID: PMC10624324 DOI: 10.1371/journal.pone.0288279] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 06/24/2023] [Indexed: 11/05/2023] Open
Abstract
The objective of this study is to evaluate the performance of functional tests using a camera-based system and machine learning techniques. Specifically, we investigate whether OpenPose and any standard camera can be used to assess the quality of the Single Leg Squat Test and Step Down Test functional tests. We recorded these exercises performed by forty-six healthy subjects, extract motion data, and classify them to expert assessments by three independent physiotherapists using 15 binary parameters. We calculated ranges of movement in Keypoint-pair orientations, joint angles, and relative distances of the monitored segments and used machine learning algorithms to predict the physiotherapists' assessments. Our results show that the AdaBoost classifier achieved a specificity of 0.8, a sensitivity of 0.68, and an accuracy of 0.7. Our findings suggest that a camera-based system combined with machine learning algorithms can be a simple and inexpensive tool to assess the performance quality of functional tests.
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Affiliation(s)
- Jindřich Adolf
- Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic
- Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic
| | - Yoram Segal
- BGU Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Matyáš Turna
- Faculty of Physical Education and Sport, Charles University, Prague, Czech Republic
| | - Tereza Nováková
- Faculty of Physical Education and Sport, Charles University, Prague, Czech Republic
| | - Jaromír Doležal
- Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic
| | - Patrik Kutílek
- Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic
| | - Jan Hejda
- Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic
| | - Ofer Hadar
- BGU Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Lenka Lhotská
- Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic
- Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic
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3
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Segal Y, Hadar O, Lhotska L. Using EfficientNet-B7 (CNN), Variational Auto Encoder (VAE) and Siamese Twins' Networks to Evaluate Human Exercises as Super Objects in a TSSCI Images. J Pers Med 2023; 13:jpm13050874. [PMID: 37241044 DOI: 10.3390/jpm13050874] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
In this article, we introduce a new approach to human movement by defining the movement as a static super object represented by a single two-dimensional image. The described method is applicable in remote healthcare applications, such as physiotherapeutic exercises. It allows researchers to label and describe the entire exercise as a standalone object, isolated from the reference video. This approach allows us to perform various tasks, including detecting similar movements in a video, measuring and comparing movements, generating new similar movements, and defining choreography by controlling specific parameters in the human body skeleton. As a result of the presented approach, we can eliminate the need to label images manually, disregard the problem of finding the start and the end of an exercise, overcome synchronization issues between movements, and perform any deep learning network-based operation that processes super objects in images in general. As part of this article, we will demonstrate two application use cases: one illustrates how to verify and score a fitness exercise. In contrast, the other illustrates how to generate similar movements in the human skeleton space by addressing the challenge of supplying sufficient training data for deep learning applications (DL). A variational auto encoder (VAE) simulator and an EfficientNet-B7 classifier architecture embedded within a Siamese twin neural network are presented in this paper in order to demonstrate the two use cases. These use cases demonstrate the versatility of our innovative concept in measuring, categorizing, inferring human behavior, and generating gestures for other researchers.
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Affiliation(s)
- Yoram Segal
- School of Electrical and Computer Engineering, Ben Gurion University of the Negev, Be'er-Sheva 84105001, Israel
| | - Ofer Hadar
- School of Electrical and Computer Engineering, Ben Gurion University of the Negev, Be'er-Sheva 84105001, Israel
| | - Lenka Lhotska
- Czech Institute of Informatics, Robotics and Cybernetics, Faculty of Biomedical Engineering, Czech Technical University in Prague, 160 00 Prague, Czech Republic
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4
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Segal Y, Hadar O, Lhotska L. Assessing Human Mobility by Constructing a Skeletal Database and Augmenting it Using a Generative Adversarial Network (GAN) Simulator. Stud Health Technol Inform 2022; 299:97-103. [PMID: 36325850 DOI: 10.3233/shti220967] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
This paper presents a neural network simulator based on anonymized patient motions that measures, categorizes, and infers human gestures based on a library of anonymized patient motions. There is a need for a sufficient training set for deep learning applications (DL). Our proposal is to extend a database that includes a limited number of videos of human physiotherapy activities with synthetic data. As a result of our posture generator, we are able to generate skeletal vectors that depict human movement. A human skeletal model is generated by using OpenPose (OP) from multiple-person videos and photographs. In every video frame, OP represents each human skeletal position as a vector in Euclidean space. The GAN is used to generate new samples and control the parameters of the motion. The joints in our skeletal model have been restructured to emphasize their linkages using depth-first search (DFS), a method for searching tree structures. Additionally, this work explores solutions to common problems associated with the acquisition of human gesture data, such as synchronizing activities and linking them to time and space. A new simulator is proposed that generates a sequence of virtual coordinated human movements based upon a script.
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Affiliation(s)
- Yoram Segal
- Department of Systems and Communication Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ofer Hadar
- Department of Systems and Communication Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Lenka Lhotska
- Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic
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5
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Jay J, Kumar V, Bidkhanian P, Garrels E, Segal Y, Susaimanickam B. Neuropsychiatric Disturbance in Huntington’s Disease: Approach to Management. Eur Psychiatry 2022. [PMCID: PMC9567710 DOI: 10.1192/j.eurpsy.2022.1208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Introduction Huntington’s Disease (HD) is an autosomal dominant, neurodegenerative condition with a prevalence of 10.6-13.7 per 100,000, caused by the trinucleotide CAG (cytosine, adenine, guanine) repeat expansion in the HTT gene. HD is characterized by a range of motor, cognitive, and psychiatric symptoms, the latter of which usually manifest prior to the onset of motor or cognitive disturbances. Amongst psychiatric symptoms, changes in personality are most common, followed by depression. Psychosis has a higher prevalence in those with early-onset
HD. Objectives This case report aims to demonstrate an apporach to the management of neuropsychiatric disturbances in HD as well as expose the need for development of an evidence-based apprach to treatment. Methods PubMed was searched for the criteria Huntington’s Disease AND Psychosis, with a secondary search for Management of Psychosis in Huntington’s Disease. Results The patient is a 54-year-old male with no psychiatric history and reported past medical history of Huntington’s Disease, diagnosed one month ago. He was brought to the Psychiatric ED due to agitation and disorganized behavior at home. On admission, he demonstrated disorganized behavior, grandiose delusions, neurocognitive deficits, and reported auditory hallucinations. With the initiation of tetrabenazine and risperidone his psychiatric symptoms improved and he was able to be discharged to a long-term care facility. Conclusions Literature is scarce regarding treatment of psychiatric manifestations of HD. We catered our approach towards safe and effective symptoms management in a multidisciplinary manner. Further research is required to reach an evidence-based consensus as well as develop specific guidelines for managing psychiatric conditions related to HD. Disclosure No significant relationships.
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6
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Lavie G, Weinstein O, Segal Y, Davidson E. Adapting to change: Clalit's response to the COVID-19 pandemic. Isr J Health Policy Res 2021; 10:68. [PMID: 34847927 PMCID: PMC8630513 DOI: 10.1186/s13584-021-00498-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 11/12/2021] [Indexed: 11/10/2022] Open
Abstract
The COVID-19 pandemic is the most significant global health event of the past century. The profound and unexpected changes that it brought about have forced healthcare organizations to make far-reaching adjustments to accommodate the new reality. With the outbreak of the pandemic in Israel and the understanding of its consequences, Clalit Health Services (Clalit), the largest healthcare organization in Israel, rapidly mobilized in order to provide the best response possible from the perspective of both its patients and its employees. In the short term, four designated workgroups were established just days into the pandemic. Their task was to prepare operational work plans to achieve the following goals: providing the best possible treatment for COVID patients; maintaining the level of care for non-COVID patients; protecting healthcare personnel without compromising their competence and level of functioning; and beginning the process of post-crisis planning. In the context of the long term, and with the understanding that the changes in healthcare brought about by the COVID-19 pandemic would be long-lasting and irreversible, and would act as a catalyst in Clalit’s preparations for the future, Clalit has carried out the called-for modifications in its organizational strategy. This was based on the need to shift service and treatment foci from the hospitals to the community and the patient’s home and his cellular device, by means of strengthening Clalit’s strategic abilities to become more proactive, more digital and more home-based. In this article, we present a survey of Clalit’s preparations for the new reality in the short and medium terms, as well as the leveraging of insights gained during the first wave of the pandemic, with goal of revising Clalit’s long-term strategic plan. We conclude and point out the organizational abilities required for optimal response to future large-scale emergencies: The ability to quickly identify the need for change, respond quickly while harnessing the various parts of the organization in order to provide an agile and adaptive response, and facilitate long-term planning activity in parallel to providing an operational response in the short and medium terms.
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Affiliation(s)
- Gil Lavie
- Clalit Health Services Management, Tel-Aviv, Israel. .,Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
| | - Orly Weinstein
- Clalit Health Services Management, Tel-Aviv, Israel.,Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yoram Segal
- Clalit Health Services Management, Tel-Aviv, Israel
| | - Ehud Davidson
- Clalit Health Services Management, Tel-Aviv, Israel.,Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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7
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Stokes HS, Martens JM, Chamings A, Walder K, Berg ML, Segal Y, Bennett A. Identification of Chlamydia gallinacea in a parrot and in free-range chickens in Australia. Aust Vet J 2019; 97:398-400. [PMID: 31310011 DOI: 10.1111/avj.12856] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/29/2019] [Accepted: 06/13/2019] [Indexed: 11/28/2022]
Abstract
Chlamydia gallinacea is a recently described bacterial species in a genus known to infect and cause disease in animals and humans. Our report describes the identification of C. gallinacea infection in free-range laying chickens (Gallus gallus) in Australia, and the identification of C. gallinacea infection in a parrot, a wild Australian galah (Eolophus roseicapillus). There is currently little knowledge of the effects of C. gallinacea infection on avian hosts, but it has been linked to respiratory disease in humans and could potentially cause similar disease in other species. Our report highlights the need for further study and surveillance of Chlamydia species in both wild and domestic hosts in Australia.
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Affiliation(s)
- H S Stokes
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
| | - J M Martens
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
| | - A Chamings
- Geelong Centre for Emerging Infectious Diseases, Geelong, Victoria, Australia.,Centre for Molecular and Medical Research, School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia
| | - K Walder
- Centre for Molecular and Medical Research, School of Medicine, Deakin University, Waurn Ponds, Victoria, Australia
| | - M L Berg
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
| | - Y Segal
- Department of Jobs, Precincts and Regions, Attwood, Victoria, Australia
| | - Atd Bennett
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
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8
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Sharaha U, Rodriguez-Diaz E, Sagi O, Riesenberg K, Lapidot I, Segal Y, Bigio IJ, Huleihel M, Salman A. Detection of Extended-Spectrum β-Lactamase-Producing Escherichia coli Using Infrared Microscopy and Machine-Learning Algorithms. Anal Chem 2019; 91:2525-2530. [DOI: 10.1021/acs.analchem.8b05497] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
| | | | - Orli Sagi
- Director of Microbiology Laboratory, Soroka University Medical Center, Beer-Sheva 84105, Israel
| | | | - Itshak Lapidot
- Department of Electrical and Electronics Engineering, ACLP-Afeka Center for Language Processing, Afeka Tel-Aviv Academic College of Engineering, Tel-Aviv 69107, Israel
| | | | | | | | - Ahmad Salman
- Department of Physics, SCE - Shamoon College of Engineering, Beer-Sheva 84100, Israel
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9
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Zhan H, Lin CHS, Segal Y, Kaushansky K. The JAK2V617F-bearing vascular niche promotes clonal expansion in myeloproliferative neoplasms. Leukemia 2017; 32:462-469. [PMID: 28744010 PMCID: PMC5783797 DOI: 10.1038/leu.2017.233] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 06/15/2017] [Accepted: 07/10/2017] [Indexed: 12/17/2022]
Abstract
The acquired kinase mutation JAK2V617F plays a central role in myeloproliferative neoplasms (MPNs). However, the mechanisms responsible for the malignant hematopoietic stem/progenitor cell (HSPC) expansion seen in patients with MPNs are not fully understood, limiting the effectiveness of current treatment. Endothelial cells (ECs) are an essential component of the hematopoietic niche, and they have been shown to express the JAK2V617F mutation in patients with MPNs. We show that the JAK2V617F-bearing vascular niche promotes the expansion of the JAK2V617F HSPCs in preference to JAK2WT HSPCs, potentially contributing to poor donor cell engraftment and disease relapse following stem cell transplantation. The expression of Chemokine (C-X-C motif) ligand 12 (CXCL12) and stem cell factor (SCF) were upregulated in JAK2V617F-bearing ECs compared to wild-type ECs, potentially accounting for this observation. We further identify that the thrombopoietin (TPO)/MPL signaling pathway is critical for the altered vascular niche function. A better understanding of how the vascular niche contributes to HSPC expansion and MPN development is essential for the design of more effective therapeutic strategies for patients with MPNs.
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Affiliation(s)
- H Zhan
- Northport VA Medical Center, Northport, NY, USA.,Department of Medicine, Stony Brook Medicine, Stony Brook, NY, USA
| | - C H S Lin
- Department of Medicine, Stony Brook Medicine, Stony Brook, NY, USA
| | - Y Segal
- Northport VA Medical Center, Northport, NY, USA
| | - K Kaushansky
- Department of Medicine, Stony Brook Medicine, Stony Brook, NY, USA.,Office of the Sr. Vice President, Health Sciences, Stony Brook Medicine, Stony Brook, NY, USA
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10
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Affiliation(s)
- N. Shenhav
- Technion-Israel Institute of Technology, Department of Nuclear Engineering Haifa, Israel
| | - Y. Segal
- Technion-Israel Institute of Technology, Department of Nuclear Engineering Haifa, Israel
| | - A. Notea
- Technion-Israel Institute of Technology, Department of Nuclear Engineering Haifa, Israel
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11
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Affiliation(s)
- Yossi Bushlin
- Technion-Israel Institute of Technology, Department of Nuclear Engineering Haifa 32000, Israel
| | - Dov Ingman
- Technion-Israel Institute of Technology, Department of Nuclear Engineering Haifa 32000, Israel
| | - Y. Segal
- Technion-Israel Institute of Technology, Department of Nuclear Engineering Haifa 32000, Israel
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12
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Affiliation(s)
- E. Elias
- Technion-Israel Institute of Technology Department of Nuclear Engineering, Haifa, Israel
| | - Y. Segal
- Technion-Israel Institute of Technology Department of Nuclear Engineering, Haifa, Israel
| | - A. Notea
- Technion-Israel Institute of Technology Department of Nuclear Engineering, Haifa, Israel
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13
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Affiliation(s)
- E. Elias
- Technion – Israel Institute of Technology Department of Nuclear Engineering, Haifa, Israel
| | - Y. Segal
- Technion – Israel Institute of Technology Department of Nuclear Engineering, Haifa, Israel
| | - A. Notea
- Technion – Israel Institute of Technology Department of Nuclear Engineering, Haifa, Israel
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14
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Brownson DA, Baratta AJ, Robinson GE, March-Leuba J, Bushlin Y, Ingman D, Segal Y, Khan HJ, Kosaly G, Nakagawa M, Malik MA, Beyrich W, Golly W, Spannagel G, De Bièvre P, Wolters WH, Lycke W, Einziger RE, Strain RV, Fumoto H, Sato S, Ito W, Tamura T, Yoshiki N, Kobayashi Y, Mao CH, Weng PS, Wheeler JK, Sesonske A. Author List. NUCL TECHNOL 2017. [DOI: 10.13182/nt86-a15971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Affiliation(s)
- Y. Segal
- Technion-Israel Institute of Technology, Department of Nuclear Science, Haifa, Israel
| | - U. German
- Technion-Israel Institute of Technology, Department of Nuclear Science, Haifa, Israel
| | - A. Notea
- Technion-Israel Institute of Technology, Department of Nuclear Science, Haifa, Israel
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16
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Affiliation(s)
- Y. Segal
- Department of Nuclear Science, Technion–Israel Institute of Technology, Haifa, Israel
| | - S. Zamir
- Department of Nuclear Science, Technion–Israel Institute of Technology, Haifa, Israel
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17
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Affiliation(s)
- A. Notea
- Technion-Israel Institute of Technology, Department of Nuclear Engineering, Haifa, Israel
| | - Y. Segal
- Technion-Israel Institute of Technology, Department of Nuclear Engineering, Haifa, Israel
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18
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Birkhofer A, Schmidt A, Werner W, Zielke LA, Wilson RH, Dias JW, Okrent D, Erdmann RC, Chitkara K, Weisman J, Moorhead AJ, DiStefano JR, McDonald RE, DeVan JH, Klueh RL, Notea A, Segal Y, Walton RB, Whitted EI, Forster RA, Foster JP, Strain RV, Sheets WR. Authors. NUCL TECHNOL 2017. [DOI: 10.13182/nt74-a31455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Affiliation(s)
- A. Knoll
- Technion-Israel Institute of Technology, Department of Nuclear Engineering, Haifa, Israel
| | - A. Notea
- Technion-Israel Institute of Technology, Department of Nuclear Engineering, Haifa, Israel
| | - Y. Segal
- Technion-Israel Institute of Technology, Department of Nuclear Engineering, Haifa, Israel
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20
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Affiliation(s)
- E. Elias
- Technion - Israel Institute of Technology Department of Nuclear Engineering Haifa 32000, Israel
| | - Y. Segal
- Technion - Israel Institute of Technology Department of Nuclear Engineering Haifa 32000, Israel
| | - A. Notea
- Technion - Israel Institute of Technology Department of Nuclear Engineering Haifa 32000, Israel
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21
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Segal Y, Garrity KF, Vaz CAF, Hoffman JD, Walker FJ, Ismail-Beigi S, Ahn CH. Dynamic evanescent phonon coupling across the La(1-x)Sr(x)MnO3/SrTiO3 interface. Phys Rev Lett 2011; 107:105501. [PMID: 21981508 DOI: 10.1103/physrevlett.107.105501] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Indexed: 05/31/2023]
Abstract
The transport and magnetic properties of correlated La0.53Sr0.47MnO3 ultrathin films, grown epitaxially on SrTiO3, show a sharp cusp at the structural transition temperature of the substrate. Using a combination of experiment and first principles theory we show that the cusp is a result of evanescent cross-interface coupling between the charge carriers in the film and a soft phonon mode in the SrTiO3, mediated through linked oxygen octahedral motions. The amplitude of the mode diverges at the transition temperature, and phonons are launched into the first few atomic layers of the film, affecting its electronic state.
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Affiliation(s)
- Y Segal
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520-8284, USA
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22
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Kolpak AM, Walker FJ, Reiner JW, Segal Y, Su D, Sawicki MS, Broadbridge CC, Zhang Z, Zhu Y, Ahn CH, Ismail-Beigi S. Interface-induced polarization and inhibition of ferroelectricity in epitaxial SrTiO₃/Si. Phys Rev Lett 2010; 105:217601. [PMID: 21231354 DOI: 10.1103/physrevlett.105.217601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2010] [Indexed: 05/30/2023]
Abstract
We use SrTiO₃/Si as a model system to elucidate the effect of the interface on ferroelectric behavior in epitaxial oxide films on silicon. Using both first-principles computations and synchrotron x-ray diffraction measurements, we show that structurally imposed boundary conditions at the interface stabilize a fixed (pinned) polarization in the film but inhibit ferroelectric switching. We demonstrate that the interface chemistry responsible for these phenomena is general to epitaxial silicon-oxide interfaces, impacting on the design of silicon-based functional oxide devices.
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Affiliation(s)
- A M Kolpak
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520-8284, USA
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23
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Vaz CAF, Hoffman J, Segal Y, Reiner JW, Grober RD, Zhang Z, Ahn CH, Walker FJ. Origin of the magnetoelectric coupling effect in Pb(Zr0.2Ti0.8)O{3}/La{0.8}Sr{0.2}MnO{3} Multiferroic heterostructures. Phys Rev Lett 2010; 104:127202. [PMID: 20366560 DOI: 10.1103/physrevlett.104.127202] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Indexed: 05/29/2023]
Abstract
The electronic valence state of Mn in Pb(Zr0.2Ti0.8)O{3}/La{0.8}Sr{0.2}MnO{3} multiferroic heterostructures is probed by near edge x-ray absorption spectroscopy as a function of the ferroelectric polarization. We observe a temperature independent shift in the absorption edge of Mn associated with a change in valency induced by charge carrier modulation in the La0.8Sr0.2MnO3, demonstrating the electronic origin of the magnetoelectric effect. Spectroscopic, magnetic, and electric characterization shows that the large magnetoelectric response originates from a modified interfacial spin configuration, opening a new pathway to the electronic control of spin in complex oxide materials.
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Affiliation(s)
- C A F Vaz
- Department of Applied Physics and CRISP, Yale University, New Haven, Connecticut 06520, USA.
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24
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Segal Y, Reiner JW, Kolpak AM, Zhang Z, Ismail-Beigi S, Ahn CH, Walker FJ. Atomic structure of the epitaxial BaO/Si(001) interface. Phys Rev Lett 2009; 102:116101. [PMID: 19392218 DOI: 10.1103/physrevlett.102.116101] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Indexed: 05/27/2023]
Abstract
We present the structure of the interface responsible for epitaxy of crystalline oxides on silicon. Using synchrotron x-ray diffraction, we observe a 2 x 1 unit cell reconstruction at the interface of BaO grown on Si(001) terminated with 1/2 ML of Sr. Since this symmetry is not present in bulk BaO or Si, only the interface contributes to diffracted intensity. First principles calculations accurately predict the observed diffraction and identify the structure of the BaO/Si interface, including the elemental composition and a sub-A rumpling due to epitaxial strain of the 7 adjacent BaO and Si layers.
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Affiliation(s)
- Y Segal
- Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520-8284, USA
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25
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Abstract
Alport syndrome, caused by mutations that interfere with the normal assembly of the alpha3alpha4alpha5(IV) collagen network in the glomerular basement membrane (GBM), is the most common inherited glomerular disease leading to renal failure. A detailed knowledge of the underlying pathogenic mechanisms is necessary for developing new, more specific, and effective therapeutic strategies aimed at delaying the onset and slowing disease progression. Studies of several dog and mouse models of Alport syndrome have significantly enhanced our understanding of the disease mechanisms and provided systems for testing potential therapies. In the most widely used Col4a3-/- mouse models of autosomal-recessive Alport syndrome (ARAS), the genetic background strongly affects renal survival. One contributing factor may be the strong ectopic deposition of alpha5alpha6(IV) collagen in the GBM of Col4a3-/- mice on the C57BL/6J background, which is almost undetectable on the 129/Sv background. This isoform 'switch' has not been observed in human ARAS, although it had been reported in the dog model of ARAS. In human patients as well as dog and mouse models of X-linked Alport syndrome, the alpha3-alpha6(IV) collagen chains are absent from the GBM. These biochemical differences among Alport animal models provide an opportunity to determine how the molecular makeup of the GBM affects the glomerular function. At the same time, potentially confounding influences of characteristics unique to a particular strain or model should be carefully considered in the design of studies aiming to define key events underlying the pathobiology of Alport glomerular disease.
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Affiliation(s)
- D Cosgrove
- Department of Genetics, Boys Town National Research Hospital, Omaha, Nebraska, USA.
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26
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Segal Y, Khain A. Dependence of droplet concentration on aerosol conditions in different cloud types: Application to droplet concentration parameterization of aerosol conditions. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006561] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Gerber JG, Rosenkranz S, Segal Y, Aberg J, D'Amico R, Mildvan D, Gulick R, Hughes V, Flexner C, Aweeka F, Hsu A, Gal J. Effect of ritonavir/saquinavir on stereoselective pharmacokinetics of methadone: results of AIDS Clinical Trials Group (ACTG) 401. J Acquir Immune Defic Syndr 2001; 27:153-60. [PMID: 11404537 DOI: 10.1097/00126334-200106010-00010] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED The effect of ritonavir 400 mg/saquinavir 400 mg twice daily on the stereoselective pharmacokinetics of methadone was examined in 12 HIV-infected, methadone-using study subjects. DESIGN A 24-hour methadone pharmacokinetic study was performed before antiretroviral therapy was begun and after 15 days of therapy. Methadone concentration was measured by a chiral plasma assay because the drug is administered as a racemic mixture of R- and S-methadone, but only the R-isomer is active. Both changes in plasma protein binding and changes in objective and subjective opioid effect were monitored. RESULTS Ritonavir/saquinavir administration was associated with 40% decrease in total S-methadone AUC0-24hr and 32% decrease in R-methadone area under the curve (AUC)0-24hr, and both changes were statistically significant (p =.001 for both). When AUC was corrected for the changes in protein binding induced by ritonavir/saquinavir, R-methadone free AUC0-24hr decreased 19.6% whereas the S-methadone decreased 24.6%, neither of these changes was statistically significant (p =.129 and p =.0537, respectively). This change in methadone exposure was not associated with any evidence of withdrawal from narcotics and no modification of methadone dose was required. CONCLUSIONS Our data indicate that ritonavir/saquinavir administration is associated with induction of metabolism of methadone but this is greater for the inactive S-methadone. However, approximately 37% of the decrease in the total R-methadone exposure can be explained by protein binding displacement. Ritonavir/saquinavir can be used in HIV-infected people taking methadone without routine dose adjustments.
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Affiliation(s)
- J G Gerber
- University of Colorado Health Sciences Center, 4200 E. 9th Avenue, Denver, CO 80262, USA.
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Chen XZ, Segal Y, Basora N, Guo L, Peng JB, Babakhanlou H, Vassilev PM, Brown EM, Hediger MA, Zhou J. Transport function of the naturally occurring pathogenic polycystin-2 mutant, R742X. Biochem Biophys Res Commun 2001; 282:1251-6. [PMID: 11302751 DOI: 10.1006/bbrc.2001.4720] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Most patients with autosomal dominant polycystic kidney disease (ADPKD) harbor mutations truncating polycystin-1 (PC1) or polycystin-2 (PC2), products of the PKD1 and PKD2 genes, respectively. A third member of the polycystin family, polycystin-L (PCL), was recently shown to function as a Ca(2+)-modulated nonselective cation channel. More recently, PC2 was also shown to be a nonselective cation channel with comparable properties to PCL, though the membrane targeting of PC2 likely varies with cell types. Here we show that PC2 expressed heterologously in Xenopus oocytes is targeted to intracellular compartments. By contrast, a truncated form of mouse PC2 corresponding to a naturally occurring human mutation R742X is targeted predominantly to the plasma membrane where it mediates K(+), Na(+), and Ca(2+) currents. Unlike PCL, the truncated form does not display Ca(2+)-activated transport activities, possibly due to loss of an EF-hand at the C-terminus. We propose that PC2 forms ion channels utilizing structural components which are preserved in the R742X form of the protein. Implications for epithelial cell signaling are discussed.
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Affiliation(s)
- X Z Chen
- Renal, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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Segal Y, Zhuang L, Rondeau E, Sraer JD, Zhou J. Regulation of the paired type IV collagen genes COL4A5 and COL4A6. Role of the proximal promoter region. J Biol Chem 2001; 276:11791-7. [PMID: 11096082 DOI: 10.1074/jbc.m007477200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [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] [Indexed: 11/06/2022] Open
Abstract
Tissue-specific expression patterns of the paired type IV collagen genes COL4A5 and COL4A6 form the basis for organ involvement in X-linked Alport syndrome, a disorder in which these genes are mutated. We investigated the proximal promoter region of COL4A5 and COL4A6 using glomerular visceral epithelial cells, in which COL4A5 alone is transcribed; keratinocytes, in which the genes are co-transcribed; and additional model cell lines. By RNase protection assays, the intergenic region is 292 base pairs. Transcription start sites for two 5' splice variants of COL4A6 are 1 kilobase apart. Transient transfections with reporter gene constructs revealed that the minimal promoters for COL4A5 and COL4A6 are within 100 base pairs of their respective transcription start sites and are functionally distinct. In further transfection, gel shift and footprinting assays, we defined a bidirectional positive regulatory element, which functions in several cell types, but not in glomerular visceral epithelial cells selectively transcribing COL4A5. The existence of separate promoters for COL4A5 and COL4A6 permits fine control over their expression. Activation through the bidirectional element can bring about co-expression of the genes, exploiting their paired arrangement. Features of the proximal promoter region frame its roles in a hierarchy regulating type IV collagen gene expression.
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Affiliation(s)
- Y Segal
- Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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Vassilev PM, Guo L, Chen XZ, Segal Y, Peng JB, Basora N, Babakhanlou H, Cruger G, Kanazirska M, Brown EM, Hediger MA, Zhou J. Polycystin-2 is a novel cation channel implicated in defective intracellular Ca(2+) homeostasis in polycystic kidney disease. Biochem Biophys Res Commun 2001; 282:341-50. [PMID: 11264013 DOI: 10.1006/bbrc.2001.4554] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Mutations in polycystins-1 and -2 (PC1 and PC2) cause autosomal dominant polycystic kidney disease (ADPKD), which is characterized by progressive development of epithelial renal cysts, ultimately leading to renal failure. The functions of these polycystins remain elusive. Here we show that PC2 is a Ca(2+)-permeable cation channel with properties distinct from any known intracellular channels. Its kinetic behavior is characterized by frequent transitions between closed and open states over a wide voltage range. The activity of the PC2 channel is transiently increased by elevating cytosolic Ca(2+). Given the predominant endoplasmic reticulum (ER) location of PC2 and its unresponsiveness to the known modulators of mediating Ca(2+) release from the ER, inositol-trisphosphate (IP(3)) and ryanodine, these results suggest that PC2 represents a novel type of channel with properties distinct from those of the other Ca(2+)-release channels. Our data also show that the PC2 channel can be translocated to the plasma membranes by defined chemical chaperones and proteasome modulators, suggesting that in vivo, it may also function in the plasma membrane under specific conditions. The sensitivity of the PC2 channel to changes of intracellular Ca(2+) concentration is deficient in a mutant found in ADPKD patients. The dysfunction of such mutants may result in defective coupling of PC2 to intracellular Ca(2+) homeostasis associated with the pathogenesis of ADPKD.
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Affiliation(s)
- P M Vassilev
- Renal Division, Brigham and Women's Hospital, Boston, Massachusetts, 02115, USA
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Chen XZ, Vassilev PM, Basora N, Peng JB, Nomura H, Segal Y, Brown EM, Reeders ST, Hediger MA, Zhou J. Polycystin-L is a calcium-regulated cation channel permeable to calcium ions. Nature 1999; 401:383-6. [PMID: 10517637 DOI: 10.1038/43907] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polycystic kidney diseases are genetic disorders in which the renal parenchyma is progressively replaced by fluid-filled cysts. Two members of the polycystin family (polycystin-1 and -2) are mutated in autosomal dominant polycystic kidney disease (ADPKD), and polycystin-L is deleted in mice with renal and retinal defects. Polycystins are membrane proteins that share significant sequence homology, especially polycystin-2 and -L (50% identity and 71% similarity). The functions of the polycystins remain unknown. Here we show that polycystin-L is a calcium-modulated nonselective cation channel that is permeable to sodium, potassium and calcium ions. Patch-clamp experiments revealed single-channel activity with a unitary conductance of 137 pS. Channel activity was substantially increased when either the extracellular or intracellular calcium-ion concentration was raised, indicating that polycystin-L may act as a transducer of calcium-mediated signalling in vivo. Its large single-channel conductance and regulation by calcium ions distinguish it from other structurally related cation channels.
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Affiliation(s)
- X Z Chen
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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Affiliation(s)
- P T Hooper
- CSIRO Australian Animal Health Laboratory, Geelong, Victoria
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Segal Y, Peissel B, Renieri A, de Marchi M, Ballabio A, Pei Y, Zhou J. LINE-1 elements at the sites of molecular rearrangements in Alport syndrome-diffuse leiomyomatosis. Am J Hum Genet 1999; 64:62-9. [PMID: 9915944 PMCID: PMC1377703 DOI: 10.1086/302213] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Deletions encompassing the 5' termini of the paired type IV collagen genes COL4A5 and COL4A6 on chromosome Xq22 give rise to Alport syndrome (AS) and associated diffuse leiomyomatosis (DL), a syndrome of disseminated smooth-muscle tumors involving the esophagus, large airways, and female reproductive tract. In this study, we report isolation and characterization of two deletion junctions. The first, in a patient described elsewhere, arose by a nonhomologous recombination event fusing a LINE-1 (L1) repetitive element in intron 1 of COL4A5 to intron 2 of COL4A6, resulting in a 13.4-kb deletion. The second, in a previously undescribed family, arose by unequal homologous recombination between the same L1 and a colinear L1 element in intron 2 of COL4A6, resulting in a>40-kb deletion. L1 elements have contributed to the emergence of this locus as a site of frequent recombinations by diverse mechanisms. These give rise to AS-DL by disruption of type IV collagen and perhaps other as yet unidentified genes, evidenced by deletions as small as 13.4 kb.
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Affiliation(s)
- Y Segal
- Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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34
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Gotlieb WH, Feldman B, Feldman-Moran O, Zmira N, Kreizer D, Segal Y, Elran E, Ben-Baruch G. Intraperitoneal pressures and clinical parameters of total paracentesis for palliation of symptomatic ascites in ovarian cancer. Gynecol Oncol 1998; 71:381-5. [PMID: 9887235 DOI: 10.1006/gyno.1998.5215] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [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: 11/22/2022]
Abstract
OBJECTIVE The present study was designed to prospectively evaluate the intraperitoneal pressure, as well as clinical and hemodynamic effects of total paracentesis, as palliation of symptomatic ascites in ovarian cancer patients. METHODS Prospective study of 35 sequential total paracenteses was performed using a Veres cannula on patients with advanced recurrent ovarian cancer with symptomatic tense ascites. Relevant clinical symptoms and patient well-being were evaluated. Vital signs, abdominal parameters, and hydrostatic intraperitoneal pressure were recorded before, during, and after the procedure. RESULTS Intraperitoneal pressure dropped from 30 +/- 7 cmH2O before paracentesis to 13 +/- 6 cmH2O after the procedure (P < 0.0001). Marked symptomatic improvement was observed in all patients (89% complete relief, 11% partial relief), while all the patients tolerated the procedure well without any complications. The mean volume of ascitic fluid removed was 4800 ml. Mean respiratory rate and mean heart rate were both significantly decreased following the procedure (29.3 to 21.4 respirations per min and 101.5 to 93.6 beats per min, respectively). Mean systolic blood pressure mildly decreased (6.6 mmHg), while the mean diastolic blood pressure did not significantly change. None of the patients presented signs or symptoms of hypovolemia during or after the total paracentesis. CONCLUSIONS Measurement of intraperitoneal pressures during total paracentesis for tense ascites in ovarian cancer patients indicated that the severity of symptoms correlated with the intraperitoneal pressure prior to paracentesis, but not with the volume of ascites. Intraperitoneal pressures measured following total paracentesis in patients with ovarian cancer were similar to the baseline intraperitoneal pressure measured in patients undergoing peritoneal dialysis.
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Affiliation(s)
- W H Gotlieb
- Department of Obstetrics and Gynecology, Tel-Aviv University, Tel-Hashomer, Israel
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35
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Abstract
Transforming growth factor beta1 (TGF-beta1) is a cytokine known to play a key role in the control of cell growth. TGF-beta1 potently inhibits the proliferation of human and rodent-derived epithelial cells. Colonic precancerous and moderately differentiated cancer cells are responsive to TGF-beta1, whereas malignant colon cancer cells are resistant to the inhibitory action of the cytokine. These observations have been derived exclusively from in vitro studies. Therefore, the main aim of our study was to determine whether TGF-beta1 exerts a growth-restraining action on colon carcinogenesis in vivo. TGF-beta1 was sequestered into ethylene acetate copolymer matrices and "loaded" preparations were implanted intraperitoneally (i.p.) in rats. One week later, the animals were treated with dimethylhydrazine (DMH), a colon procarcinogen. Empty matrices devoid of TGF-beta1 but containing bovine serum albumin (BSA) carrier served as the appropriate control preparations. The number of aberrant crypt foci (ACF), considered to be preneoplastic lesions of the colon, was scored. Tumor formation and size were assessed at the appropriate times. TGF-beta1 released in a sustained manner from copolymer matrices: (i) markedly inhibited colonic ACF formation and the number of aberrant crypts and (ii) significantly reduced colonic tumor formation and size.
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Affiliation(s)
- R Mikhailowski
- Gastroenterology Department, Soroka Medical Center, Beer Sheva, Israel
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36
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Sasaki S, Zhou B, Fan WW, Kim Y, Barker DF, Denison JC, Atkin CL, Gregory MC, Zhou J, Segal Y, Sado Y, Ninomiya Y, Michael AF, Kashtan CE. Expression of mRNA for type IV collagen alpha1, alpha5 and alpha6 chains by cultured dermal fibroblasts from patients with X-linked Alport syndrome. Matrix Biol 1998; 17:279-91. [PMID: 9749944 DOI: 10.1016/s0945-053x(98)90081-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
COL4A5 mutations causing X-linked Alport syndrome (XLAS) are frequently associated with absence of the alpha3, alpha4,alpha5 and alpha6 chains of type IV collagen from basement membranes and increased amounts of the alpha1(IV) and alpha2(IV) chains in glomerular basement membrane. Although many COL4A5 mutations have been described in XLAS, the mechanisms by which these mutations influence the basement membrane appearance of chains other than alpha5(IV) remain poorly understood. In this study, we used dermal fibroblasts from eight normal individuals and nine males with XLAS to test the hypotheses that COL4A5 mutations increase transcription of COL4A1 and suppress transcription of COL4A6. Ribonuclease protection assays revealed that alpha1(IV), alpha5(IV) and alpha6(IV) transcripts were expressed in cultures of dermal fibroblasts. The mRNA levels for alpha1(IV) in eight of nine patients with XLAS were not increased compared to controls; one patient with a large COL4A5 deletion showed significant elevation of alpha1(IV) mRNA levels. No differences in steady-state mRNA levels for alpha6(IV) were found when XLAS fibroblasts were compared with controls, even though little or no alpha6(IV) protein was detectable at the dermal-epidermal junction by immunofluorescence study. This finding suggests that post-transcriptional events account for the absence of alpha6(IV) in the Alport dermal-epidermal junction.
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Affiliation(s)
- S Sasaki
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis 55455, USA
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Geng L, Segal Y, Pavlova A, Barros EJ, Löhning C, Lu W, Nigam SK, Frischauf AM, Reeders ST, Zhou J. Distribution and developmentally regulated expression of murine polycystin. Am J Physiol 1997; 272:F451-9. [PMID: 9140045 DOI: 10.1152/ajprenal.1997.272.4.f451] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PKD1, the gene that is mutated in approximately 85% of autosomal dominant polycystic kidney disease (ADPKD) cases in humans, has recently been identified (Eur. PKD Consortium. Cell 77: 881-894, 1994; also, erratum in Cell 78: 1994). The longest open-reading frame of PKD1 encodes polycystin, a novel approximately 460-kDa protein that contains a series of NH2-terminal adhesive domains (J. Hughes, C. J. Ward, B. Peral, R. Aspinwall, K. Clark, J. San Millan, V. Gamble, and P. C. Harris. Nat. Genet. 10: 151-160, 1995; and Int. PKD Consortium. Cell 81: 289-298, 1995) and several putative transmembrane segments. To extend studies of polycystin to an experimentally accessible animal, we have isolated a cDNA clone encoding the 3' end of Pkd1, the mouse homologue of PKD1, and raised a specific antibody to recombinant murine polycystin. This antibody was used to determine the subcellular localization and tissue distribution of the protein by Western analysis and immunocytochemistry. In the mouse, polycystin is an approximately 400-kDa molecule that is predominantly found in membrane fractions of tissue and cell extracts. It is expressed in many tissues including kidney, liver, pancreas, heart, intestine, lung, and brain. Renal expression, which is confined to tubular epithelia, is highest in late fetal and early neonatal life and drops 20-fold by the third postnatal week, maintaining this level into adulthood. Thus the temporal profile of polycystin expression coincides with kidney tubule differentiation and maturation.
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Affiliation(s)
- L Geng
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Geng L, Segal Y, Peissel B, Deng N, Pei Y, Carone F, Rennke HG, Glücksmann-Kuis AM, Schneider MC, Ericsson M, Reeders ST, Zhou J. Identification and localization of polycystin, the PKD1 gene product. J Clin Invest 1996; 98:2674-82. [PMID: 8981910 PMCID: PMC507729 DOI: 10.1172/jci119090] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Polycystin, the product of autosomal dominant polycystic kidney disease (ADPKD) 1 gene (PKD1) is the cardinal member of a novel class of proteins. As a first step towards elucidating the function of polycystin and the pathogenesis of ADPKD, three types of information were collected in the current study: the subcellular localization of polycystin, the spatial and temporal distribution of the protein within normal tissues and the effects of ADPKD mutations on the pattern of expression in affected tissues. Antisera directed against a synthetic peptide and two recombinant proteins of different domains of polycystin revealed the presence of an approximately 400-kD protein (polycystin) in the membrane fractions of normal fetal, adult, and ADPKD kidneys. Immunohistological studies localized polycystin to renal tubular epithelia, hepatic bile ductules, and pancreatic ducts, all sites of cystic changes in ADPKD, as well as in tissues such as skin that are not known to be affected in ADPKD. By electron microscopy, polycystin was predominantly associated with plasma membranes. Polycystin was significantly less abundant in adult than in fetal epithelia. In contrast, polycystin was overexpressed in most, but not all, cysts in ADPKD kidneys.
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Affiliation(s)
- L Geng
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Copello J, Heming TA, Segal Y, Reuss L. cAMP-activated apical membrane chloride channels in Necturus gallbladder epithelium. Conductance, selectivity, and block. J Gen Physiol 1993; 102:177-99. [PMID: 8228907 PMCID: PMC2229151 DOI: 10.1085/jgp.102.2.177] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Elevation of intracellular cAMP levels in Necturus gallbladder epithelium (NGB) induces an apical membrane Cl- conductance (GaCl). Its characteristics (i.e., magnitude, anion selectivity, and block) were studied with intracellular microelectrode techniques. Under control conditions, the apical membrane conductance (Ga) was 0.17 mS.cm-2, primarily ascribable to GaK. With elevation of cell cAMP to maximum levels, Ga increased to 6.7 mS.cm-2 and became anion selective, with the permeability sequence SCN- > NO3- > I- > Br- > Cl- >> SO4(2-) approximately gluconate approximately cyclamate. GaCl was not affected by the putative Cl- channel blockers Cu2+, DIDS, DNDS, DPC, furosemide, IAA-94, MK-196, NPPB, SITS, verapamil, and glibenclamide. To characterize the cAMP-activated Cl- channels, patch-clamp studies were conducted on the apical membrane of enzyme-treated gallbladders or on dissociated cells from tissues exposed to both theophylline and forskolin. Two kinds of Cl- channels were found. With approximately 100 mM Cl- in both bath and pipette, the most frequent channel had a linear current-voltage relationship with a slope conductance of approximately 10 pS. The less frequent channel was outward rectifying with slope conductances of approximately 10 and 20 pS at -40 and 40 mV, respectively. The Cl- channels colocalized with apical maxi-K+ channels in 70% of the patches. The open probability (Po) of both kinds of Cl- channels was variable from patch to patch (0.3 on average) and insensitive to [Ca2+], membrane voltage, and pH. The channel density (approximately 0.3/patch) was one to two orders of magnitude less than that required to account for GaCl. However, addition of 250 U/ml protein kinase A plus 1 mM ATP to the cytosolic side of excised patches increased the density of the linear 10-pS Cl- channels more than 10-fold to four per patch and the mean Po to 0.5, close to expectations from GaCl. The permeability sequence and blocker insensitivity of the PKA-activated channels were identical to those of the apical membrane. These data strongly suggest that 10-pS Cl- channels are responsible for the cAMP-induced increase in apical membrane conductance of NGB epithelium.
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Affiliation(s)
- J Copello
- Department of Physiology, University of Texas Medical Branch, Galveston 77555
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Tepper R, Nahum R, Rahamim E, Kapolovitz Y, Segal Y, Karib N, Beyth Y. Effects of methotrexate on rabbit oviducts and on cell cultures of bovine oviduct epithelium. Gynecol Obstet Invest 1992; 33:65-8. [PMID: 1559627 DOI: 10.1159/000294850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The influence of a local injection of 0.05 ml/kg weight of 8 mg/ml methotrexate (MTX) was evaluated in 6 rabbit oviducts and compared with saline injections to the contralateral oviducts. Cell cultures of bovine oviducts were incubated in vitro for 7 days and then incubated for 24 h with 100-nmol MTX. Forty-eight and 72 h following the exposure to MTX, the treated and control cultures were harvested. Specimens and cultures were examined by light and scanning electron microscopy. In the in vivo cohort, no differences were observed between MTX and control groups. However, in MTX-treated cell culture, ciliated cells demonstrated partially adherent cilia in about 30% of the cells. The effect of MTX observed only in vitro treated cells may be due to the rapid proliferation of epithelial cells in culture which does not represent the physiological role of the oviduct in vivo.
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Affiliation(s)
- R Tepper
- Department of Obstetrics and Gynecology A, Sapir Medical Center, Kfar Saba, Israel
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Affiliation(s)
- L Reuss
- Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77550
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Copello J, Simon B, Segal Y, Wehner F, Ramanujam VM, Alcock N, Reuss L. Ba2+ release from soda glass modifies single maxi K+ channel activity in patch clamp experiments. Biophys J 1991; 60:931-41. [PMID: 1742460 PMCID: PMC1260144 DOI: 10.1016/s0006-3495(91)82127-0] [Citation(s) in RCA: 11] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Glasses used to fabricate patch pipettes may release components which affect ion channels (Cota, G., and C.M. Armstrong. 1988. Biophys. J. 53:107-109; Furman, R.E., and J.C. Tanaka. 1988. Biophys. J. 53:287-292; Rojas, L., and C. Zuazaga. 1988. Neurosci. Lett. 88:39-44). The gating properties of maxi K+ channels from Necturus gallbladder epithelium depend on whether borosilicate glass (BG) or blue tip hematocrit glass (SG) is used to construct the patch pipettes. The data are consistent with solubilization from SG of a component which exerts voltage-dependent, cytosolic-side specific block, closely resembling "slow block" by Ba2+ ions. Ringer's solution preincubated with SG, but not with BG, blocked inside-out maxi K+ channels when used as bathing solution. Mass spectrometry revealed that Ba2+ is released by the glass from fast and slow-release compartments (SG contains 3% wt/wt BaO), and is the only ion found in the solution at concentrations consistent with the observed channel block. Additionally, SG released O2-, Na+, Ca2+, and Mg2+, all to micromolar concentrations. These elements do not interfere with maxi K+ channels but they could in principle alter the properties of other ion channels. Thus, screening for channel-modifying substances released by the glass may be necessary for the adequate interpretation of patch-clamp results.
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Affiliation(s)
- J Copello
- Department of Physiology, University of Texas Medical Branch, Galveston 77550
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Abstract
1. The patch clamp technique was used to study the effects of internal and external pH on the Ca(2+)- and voltage-activated maxi K+ channel present in the apical membrane of Necturus gall-bladder epithelial cells. 2. When the pH of the solution bathing the cytosolic side of inside-out patches (pHi) was lowered from 7.9 to 6.9, with internal free Ca2+ concentration ([Ca2+]i) buffered below saturation levels for the channel gating sites, channel open probability (Po) decreased. At saturating Ca2+ concentrations, Po was near 1.0, and unaffected by pHi. The results are consistent with a competitive interaction between Ca2+ and H+ at regulatory binding sites. Kinetic analysis assuming competitive binding yields a Hill coefficient for H+ of 1.3. 3. At sub-maximal [Ca2+]i, changing the pH of the solution bathing the extracellular surface of the patch (pHo) between 8 and 7, had no effect on maxi K+ channel Po, but lowering pHo to 6 or 5 significantly reduced Po. At saturating [Ca2+]i, Po was independent of pHo. 4. There were no effects of either pHi or pHo on single-channel conductance. 5. Inasmuch as reductions in either pHo or pHi decrease maxi K+ channel Po, changes in maxi K+ channel activity account in part for the reduction of apical membrane K+ conductance elicited by acidification of the bathing medium. The dominant effect of pH on maxi K+ channels is on the cytosolic surface of the membrane. 6. The change in Po elicited by small changes in [H+]i (delta Po/delta [H+]i) is -7.6 microM-1, compared to delta Po/delta [Ca2+]i = 2.6 microM-1, both at Vm = -30 mV and at physiological intracellular [H+] and [Ca2+]. This implies that [H+]i and [Ca2+]i have opposite effects on channel Po at physiological levels and underlines the importance of pHi in channel gating.
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Affiliation(s)
- J Copello
- Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77550
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Abstract
The apical membrane of Necturus gallbladder epithelium contains a voltage-activated K+ conductance [Ga(V)]. Large-conductance (maxi) K+ channels underlie Ga(V) and account for 17% of the membrane conductance (Ga) under control conditions. We examined the Ba2+, tetraethylammonium (TEA+), and quinine sensitivities of Ga and single maxi K+ channels. Mucosal Ba2+ addition decreased resting Ga in a concentration-dependent manner (65% block at 5 mM) and decreased Ga(V) in a concentration- and voltage-dependent manner. Mucosal TEA+ addition also decreased control Ga (60% reduction at 5 mM). TEA+ block of Ga(V) was more potent and less voltage dependent that Ba2+ block. Maxi K+ channels were blocked by external Ba2+ at millimolar levels and by external TEA+ at submillimolar levels. At 0.3 mM, quinine (mucosal addition) hyperpolarized the cell membranes by 6 mV and reduced the fractional apical membrane resistance by 50%, suggesting activation of an apical membrane K+ conductance. At 1 mM, quinine both activated and blocked K(+)-conductive pathways. Quinine blocked maxi K+ channel currents at submillimolar concentrations. We conclude that 1) Ba2+ and TEA+ block maxi K+ channels and other K+ channels underlying resting Ga; 2) parallels between the Ba2+ and TEA+ sensitivities of Ga(V) and maxi K+ channels support a role for these channels in Ga(V); and 3) quinine has multiple effects on K(+)-conductive pathways in gallbladder epithelium, which are only partially explained by block of apical membrane maxi K+ channels.
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Affiliation(s)
- Y Segal
- Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77550
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Abstract
A preparation has been developed that permits patch clamping of the basolateral membrane of Necturus gallbladder epithelial cells with a high success rate. The epithelium is separated from the underlying tissues mechanically, without enzymatic treatment. Its apical surface is attached to a plastic cover slip, and the basolateral surface, facing up, is cleaned with a suction pipette under microscopic observation. With this cleaning procedure, the success rate in obtaining gigaohm seals increases from less than 1% to approximately 10% of the attempts. The cells appear to retain their structural and functional integrity, as evidenced by electron-microscopic appearance and magnitude of cell membrane voltages. Major advantages of the preparation are that the basolateral membrane domain is preserved and that enzymatic treatment, which could potentially alter membrane proteins, is not necessary.
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Affiliation(s)
- F Wehner
- Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77550
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Abstract
Using the patch-clamp technique, we have identified large-conductance (maxi) K+ channels in the apical membrane of Necturus gallbladder epithelium, and in dissociated gallbladder epithelial cells. These channels are more than tenfold selective for K+ over Na+, and exhibit unitary conductance of approximately 200 pS in symmetric 100 mM KCl. They are activated by elevation of internal Ca2+ levels and membrane depolarization. The properties of these channels could account for the previously observed voltage and Ca2+ sensitivities of the macroscopic apical membrane conductance (Ga). Ga was determined as a function of apical membrane voltage, using intracellular microelectrode techniques. Its value was 180 microS/cm2 at the control membrane voltage of -68 mV, and increased steeply with membrane depolarization, reaching 650 microS/cm2 at -25 mV. We have related maxi K+ channel properties and Ga quantitatively, relying on the premise that at any apical membrane voltage Ga comprises a leakage conductance and a conductance due to maxi K+ channels. Comparison between Ga and maxi K+ channels reveals that the latter are present at a surface density of 0.09/microns 2, are open approximately 15% of the time under control conditions, and account for 17% of control Ga. Depolarizing the apical membrane voltage leads to a steep increase in channel steady-state open probability. When correlated with patch-clamp studies examining the Ca2+ and voltage dependencies of single maxi K+ channels, results from intracellular microelectrode experiments indicate that maxi K+ channel activity in situ is higher than predicted from the measured apical membrane voltage and estimated bulk cytosolic Ca2+ activity. Mechanisms that could account for this finding are proposed.
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Affiliation(s)
- Y Segal
- Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77550-2781
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Altenberg G, Copello J, Cotton C, Dawson K, Segal Y, Wehner F, Reuss L. Electrophysiological methods for studying ion and water transport in Necturus gall bladder epithelium. Methods Enzymol 1990; 192:650-83. [PMID: 2074812 DOI: 10.1016/0076-6879(90)92101-i] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Segal Y, Gutman A, Fishman A, Notea A. Point spread functions due to neutron scattering in thermal neutron radiography of aluminum, iron, zircaloy and polyethelene objects. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0167-5087(82)90353-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Clark DE, Urwongse L, Maurer C, Coles DG, Bazan F, Johnson LH, Shoesmith DW, Lunansky GE, Bailey MG, Tremaine PR, Schuman RP, Simmons JH, Barkatt A, Macedo PB, Barkatt A, Barkatt A, Pehr PE, Macedo PB, Simmons JH, Kennedy CR, Flynn KF, Arons RM, Dusek JT, Scheetz BE, White WB, Atkinson SD, Pescatore C, Machiels AJ, Staples BA, Paige BE, Rhodes DW, Wilding MW, Strachan DM, Turcotte RP, Barnes BO, Pizzica PA, Hummel HH, LaBauve RJ, England TR, George DC, Maynard CW, Williford RE, Lanning DD, Mohr CL, Knoll A, Notea A, Segal Y, Blomeke JO, Croff AG, Nejat S, Tsoulfanidis N, Sanders RC, Groehn HG, Patel VN, Anno JN. Authors — February 1982. NUCL TECHNOL 1982. [DOI: 10.13182/nt82-a32846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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