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Tobe Y, Robertson AM, Ramezanpour M, Cebral JR, Watkins SC, Charbel FT, Amin-Hanjani S, Yu AK, Cheng BC, Woo HH. Comapping Cellular Content and Extracellular Matrix with Hemodynamics in Intact Arterial Tissues Using Scanning Immunofluorescent Multiphoton Microscopy. Microsc Microanal 2024:ozae025. [PMID: 38525887 DOI: 10.1093/mam/ozae025] [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] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/26/2024]
Abstract
Deviation of blood flow from an optimal range is known to be associated with the initiation and progression of vascular pathologies. Important open questions remain about how the abnormal flow drives specific wall changes in pathologies such as cerebral aneurysms where the flow is highly heterogeneous and complex. This knowledge gap precludes the clinical use of readily available flow data to predict outcomes and improve treatment of these diseases. As both flow and the pathological wall changes are spatially heterogeneous, a crucial requirement for progress in this area is a methodology for acquiring and comapping local vascular wall biology data with local hemodynamic data. Here, we developed an imaging pipeline to address this pressing need. A protocol that employs scanning multiphoton microscopy was developed to obtain three-dimensional (3D) datasets for smooth muscle actin, collagen, and elastin in intact vascular specimens. A cluster analysis was introduced to objectively categorize the smooth muscle cells (SMC) across the vascular specimen based on SMC actin density. Finally, direct quantitative comparison of local flow and wall biology in 3D intact specimens was achieved by comapping both heterogeneous SMC data and wall thickness to patient-specific hemodynamic results.
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Affiliation(s)
- Yasutaka Tobe
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Mehdi Ramezanpour
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, VA 22030, USA
| | - Simon C Watkins
- Department of Cell Biology, University of Pittsburgh, PA 15261, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Sepideh Amin-Hanjani
- Department of Neurological Surgery, University Hospital Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Alexander K Yu
- Department of Neurological Surgery, Allegheny Health Network, Pittsburgh, PA 15212, USA
| | - Boyle C Cheng
- Neuroscience and Orthopedic Institutes, Allegheny Health Network, Pittsburgh, PA 15212, USA
| | - Henry H Woo
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra Northwell, Manhasset, NY 11549, USA
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2
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Tobe Y, Yagi T, Kawamura K, Suto K, Sawada Y, Hayashi Y, Yoshida H, Nishitani K, Okada Y, Kitahara S, Umezu M. Three-dimensional wall-thickness distributions of unruptured intracranial aneurysms characterized by micro-computed tomography. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01835-5. [PMID: 38489080 DOI: 10.1007/s10237-024-01835-5] [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: 11/27/2023] [Accepted: 02/21/2024] [Indexed: 03/17/2024]
Abstract
Aneurysmal rupture is associated with wall thinning, but the mechanism is poorly understood. This study aimed to characterize the three-dimensional wall-thickness distributions of unruptured intracranial aneurysms. Five aneurysmal tissues were investigated using micro-computed tomography. First, the wall thickness was related to the aneurysmal wall appearances during surgery. The median wall thicknesses of the translucent and non-translucent walls were 50.56 and 155.93 µm, respectively (p < 0.05) with significant variation in the non-translucent wall thicknesses (p < 0.05). The three-dimensional observations characterized the spatial variation of wall thicknesses. Thin walls showed a uniform thickness profile ranging from 10 to 40 µm, whereas thick walls presented a peaked thickness profile ranging from 300 to 500 µm. In transition walls, the profile undulated due to the formation of focal thin/thick spots. Overall, the aneurysmal wall thicknesses were strongly site-dependent and spatially varied by 10 to 40 times within individual cases. Aneurysmal walls are exposed to wall stress driven by blood pressure. In theory, the magnitude of wall stress is inversely proportional to wall thickness. Thus, the observed spatial variation of wall thickness may increase the spatial variation of wall stress to a similar extent. The irregular wall thickness may yield stress concentration. The observed thin walls and focal thin spots may be caused by excessive wall stresses at the range of mechanical failure inducing wall injuries, such as microscopic tears, during aneurysmal enlargement. The present results suggested that blood pressure (wall stress) may have a potential of acting as a trigger of aneurysmal wall injury.
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Affiliation(s)
- Yasutaka Tobe
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan
| | - Takanobu Yagi
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan.
| | - Koichi Kawamura
- Second Department of Pathology, Akita University, Akita, Japan
| | - Kenta Suto
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan
| | - Yoichi Sawada
- Department of Health and Welfare Science, Okayama Prefectural University, Okayama, Japan
| | - Yoshifumi Hayashi
- Department of Neurosurgery, Kitahara International Hospital, Tokyo, Japan
| | - Hirotaka Yoshida
- Department of Neurosurgery, Tokyo General Hospital, Tokyo, Japan
| | | | - Yoshifumi Okada
- Department of Neurosurgery, Kitahara International Hospital, Tokyo, Japan
| | - Shigemi Kitahara
- Department of Neurosurgery, Kitahara International Hospital, Tokyo, Japan
| | - Mitsuo Umezu
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan
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3
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Tobe Y, Robertson A, Ramezanpour M, Cebral J, Watkins S, Charbel F, Amin-Hanjani S, Yu A, Cheng B, Woo H. Co-mapping Cellular Content and Extracellular Matrix with Hemodynamics in Intact Arterial Tissues Using Scanning Immunofluorescent Multiphoton Microscopy. ArXiv 2024:arXiv:2305.10253v2. [PMID: 37292464 PMCID: PMC10246116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Deviation of blood flow from an optimal range is known to be associated with the initiation and progression of vascular pathologies. Important open questions remain about how the abnormal flow drives specific wall changes in pathologies such as cerebral aneurysms where the flow is highly heterogeneous and complex. This knowledge gap precludes the clinical use of readily available flow data to predict outcomes and improve treatment of these diseases. As both flow and the pathological wall changes are spatially heterogeneous, a crucial requirement for progress in this area is a methodology for co-mapping local data from vascular wall biology with local hemodynamic data. In this study, we developed an imaging pipeline to address this pressing need. A protocol that employs scanning multiphoton microscopy was designed to obtain 3D data sets for smooth muscle actin, collagen and elastin in intact vascular specimens. A cluster analysis was developed to objectively categorize the smooth muscle cells (SMC) across the vascular specimen based on SMC density. In the final step in this pipeline, the location specific categorization of SMC, along with wall thickness was co-mapped with patient specific hemodynamic results, enabling direct quantitative comparison of local flow and wall biology in 3D intact specimens.
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4
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Ramezanpour M, Robertson AM, Tobe Y, Jia X, Cebral JR. Phenotyping calcification in vascular tissues using artificial intelligence. ArXiv 2024:arXiv:2401.07825v2. [PMID: 38313202 PMCID: PMC10836085] [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] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Vascular calcification is implicated as an important factor in major adverse cardiovascular events (MACE), including heart attack and stroke. A controversy remains over how to integrate the diverse forms of vascular calcification into clinical risk assessment tools. Even the commonly used calcium score for coronary arteries, which assumes risk scales positively with total calcification, has important inconsistencies. Fundamental studies are needed to determine how risk is influenced by the diverse calcification phenotypes. However, studies of these kinds are hindered by the lack of high-throughput, objective, and non-destructive tools for classifying calcification in imaging data sets. Here, we introduce a new classification system for phenotyping calcification along with a semi-automated, non-destructive pipeline that can distinguish these phenotypes in even atherosclerotic tissues. The pipeline includes a deep-learning-based framework for segmenting lipid pools in noisy μ-CT images and an unsupervised clustering framework for categorizing calcification based on size, clustering, and topology. This approach is illustrated for five vascular specimens, providing phenotyping for thousands of calcification particles across as many as 3200 images in less than seven hours. Average Dice Similarity Coefficients of 0.96 and 0.87 could be achieved for tissue and lipid pool, respectively, with training and validation needed on only 13 images despite the high heterogeneity in these tissues. By introducing an efficient and comprehensive approach to phenotyping calcification, this work enables large-scale studies to identify a more reliable indicator of the risk of cardiovascular events, a leading cause of global mortality and morbidity.
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Affiliation(s)
- Mehdi Ramezanpour
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA, USA
| | - Anne M. Robertson
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA, USA
| | - Yasutaka Tobe
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA, USA
| | - Xiaowei Jia
- Department of Computer Science, University of Pittsburgh, PA, USA
| | - Juan R. Cebral
- Department of Mechanical Engineering, George Mason University, Fairfax, Virginia, USA
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Salimi Ashkezari SF, Mut F, Slawski M, Cheng B, Yu AK, White TG, Woo HH, Koch MJ, Amin-Hanjani S, Charbel FT, Rezai Jahromi B, Niemelä M, Koivisto T, Frosen J, Tobe Y, Maiti S, Robertson AM, Cebral JR. Prediction of bleb formation in intracranial aneurysms using machine learning models based on aneurysm hemodynamics, geometry, location, and patient population. J Neurointerv Surg 2021; 14:1002-1007. [PMID: 34686573 PMCID: PMC9023610 DOI: 10.1136/neurintsurg-2021-017976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 06/29/2021] [Accepted: 10/08/2021] [Indexed: 11/04/2022]
Abstract
BACKGROUND Bleb presence in intracranial aneurysms (IAs) is a known indication of instability and vulnerability. OBJECTIVE To develop and evaluate predictive models of bleb development in IAs based on hemodynamics, geometry, anatomical location, and patient population. METHODS Cross-sectional data (one time point) of 2395 IAs were used for training bleb formation models using machine learning (random forest, support vector machine, logistic regression, k-nearest neighbor, and bagging). Aneurysm hemodynamics and geometry were characterized using image-based computational fluid dynamics. A separate dataset with 266 aneurysms was used for model evaluation. Model performance was quantified by the area under the receiving operating characteristic curve (AUC), true positive rate (TPR), false positive rate (FPR), precision, and balanced accuracy. RESULTS The final model retained 18 variables, including hemodynamic, geometrical, location, multiplicity, and morphology parameters, and patient population. Generally, strong and concentrated inflow jets, high speed, complex and unstable flow patterns, and concentrated, oscillatory, and heterogeneous wall shear stress patterns together with larger, more elongated, and more distorted shapes were associated with bleb formation. The best performance on the validation set was achieved by the random forest model (AUC=0.82, TPR=91%, FPR=36%, misclassification error=27%). CONCLUSIONS Based on the premise that aneurysm characteristics prior to bleb formation resemble those derived from vascular reconstructions with their blebs virtually removed, machine learning models can identify aneurysms prone to bleb development with good accuracy. Pending further validation with longitudinal data, these models may prove valuable for assessing the propensity of IAs to progress to vulnerable states and potentially rupturing.
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Affiliation(s)
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Martin Slawski
- Department of Statistics, George Mason University, Fairfax, Virginia, USA
| | - Boyle Cheng
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Alexander K Yu
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Tim G White
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York, USA
| | - Henry H Woo
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York, USA
| | - Matthew J Koch
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Sepideh Amin-Hanjani
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Behnam Rezai Jahromi
- Neurosurgery Research Group, Biomedicum Helsinki, University of Helsinki, Helsinki, Uusimaa, Finland
| | - Mika Niemelä
- Department of Neurosurgery, Töölö Hospital, University of Helsinki, Helsinki, Finland
| | - Timo Koivisto
- Department of Neurosurgery, Kuopio University Hospital, Kuopio, Pohjois-Savo, Finland
| | - Juhana Frosen
- Department of Neurosurgery, Tampere University Hospital, Tampere, Finland.,Hemorrhagic Brain Pathology Research Group, NeuroCenter, Kuopio University Hospital, Kuopio, Pohjois-Savo, Finland
| | - Yasutaka Tobe
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Spandan Maiti
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA.,Department of Mechanical Engineering, George Mason University, Fairfax, Virginia, USA
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Cebral JR, Detmer F, Chung BJ, Choque-Velasquez J, Rezai B, Lehto H, Tulamo R, Hernesniemi J, Niemela M, Yu A, Williamson R, Aziz K, Shakur S, Amin-Hanjani S, Charbel F, Tobe Y, Robertson A, Frösen J. Local Hemodynamic Conditions Associated with Focal Changes in the Intracranial Aneurysm Wall. AJNR Am J Neuroradiol 2019; 40:510-516. [PMID: 30733253 DOI: 10.3174/ajnr.a5970] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/25/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Aneurysm hemodynamics has been associated with wall histology and inflammation. We investigated associations between local hemodynamics and focal wall changes visible intraoperatively. MATERIALS AND METHODS Computational fluid dynamics models were constructed from 3D images of 65 aneurysms treated surgically. Aneurysm regions with different visual appearances were identified in intraoperative videos: 1) "atherosclerotic" (yellow), 2) "hyperplastic" (white), 3) "thin" (red), 4) rupture site, and 5) "normal" (similar to parent artery), They were marked on 3D reconstructions. Regional hemodynamics was characterized by the following: wall shear stress, oscillatory shear index, relative residence time, wall shear stress gradient and divergence, gradient oscillatory number, and dynamic pressure; these were compared using the Mann-Whitney test. RESULTS Hyperplastic regions had lower average wall shear stress (P = .005) and pressure (P = .009) than normal regions. Flow conditions in atherosclerotic and hyperplastic regions were similar but had higher average relative residence time (P = .03) and oscillatory shear index (P = .04) than thin regions. Hyperplastic regions also had a higher average gradient oscillatory number (P = .002) than thin regions. Thin regions had lower average relative residence time (P < .001), oscillatory shear index (P = .006), and gradient oscillatory number (P < .001) than normal regions, and higher average wall shear stress (P = .006) and pressure (P = .009) than hyperplastic regions. Thin regions tended to be aligned with the flow stream, while atherosclerotic and hyperplastic regions tended to be aligned with recirculation zones. CONCLUSIONS Local hemodynamics is associated with visible focal wall changes. Slow swirling flow with low and oscillatory wall shear stress was associated with atherosclerotic and hyperplastic changes. High flow conditions prevalent in regions near the flow impingement site characterized by higher and less oscillatory wall shear stress were associated with local "thinning" of the wall.
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Affiliation(s)
- J R Cebral
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - F Detmer
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - B J Chung
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - J Choque-Velasquez
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - B Rezai
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - H Lehto
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - R Tulamo
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland.,Department of Vascular Surgery (R.T.), Helsinki University Central Hospital, Helsinki, Finland
| | - J Hernesniemi
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - M Niemela
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - A Yu
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - R Williamson
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - K Aziz
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - S Shakur
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - S Amin-Hanjani
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - F Charbel
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - Y Tobe
- Mechanical Engineering and Materials Science and Department of Bioengineering (Y.T., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - A Robertson
- Mechanical Engineering and Materials Science and Department of Bioengineering (Y.T., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - J Frösen
- Hemorrhagic Brain Pathology Research Group (J.F.), Neurocenter, Kuopio University Hospital, Kuopio, Finland
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7
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Cebral JR, Mut F, Gade P, Cheng F, Tobe Y, Frosen J, Robertson AM. Combining data from multiple sources to study mechanisms of aneurysm disease: Tools and techniques. Int J Numer Method Biomed Eng 2018; 34:e3133. [PMID: 30055087 PMCID: PMC6231954 DOI: 10.1002/cnm.3133] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [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: 04/25/2018] [Revised: 06/14/2018] [Accepted: 07/15/2018] [Indexed: 05/31/2023]
Abstract
INTRODUCTION Connecting local hemodynamics, biomechanics, and tissue properties in cerebral aneurysms is important for understanding the processes of wall degeneration and subsequent aneurysm progression and rupture. This challenging problem requires integration of data from multiple sources. METHODS This paper describes the tools and techniques developed to integrate data from multiple sources, including clinical information, 3D imaging, intraoperative videos, ex vivo micro-computed tomography (CT), and multiphoton microscopy. Central to this approach is a 3D tissue model constructed from micro-CT images of aneurysm samples resected during neurosurgery. This model is aligned to vascular models constructed from 3D clinical images and is used to map and compare flow, biomechanics, and tissue data. RESULTS The approach is illustrated with data of three human intracranial aneurysms. These case studies demonstrated the ability of this approach to study relationships between different factors affecting the aneurysm wall and produced provocative observations that will be further studied with larger series. For instance, "atherosclerotic" and "hyperplastic" looking parts of the aneurysm corresponded to thicker walls and occurred in regions of recirculating flow and low wall shear stress (WSS); thin regions were associated with inflow jets, flow impingement, and high WSS; blebs had walls of varying structures, including calcified, thin, or hyperplastic walls. CONCLUSIONS The current approach enables the study of interactions of multiple factors thought to be responsible for the progressive degradation and weakening of the aneurysm wall during its evolution.
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Affiliation(s)
- Juan R Cebral
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Fernando Mut
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Piyusha Gade
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Fangzhou Cheng
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yasutaka Tobe
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juhana Frosen
- Hemorrhagic Brain Pathology Research Group, Neurocenter, Kuopio University Hospital, Kuopio, Finland
| | - Anne M Robertson
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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8
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Yagi T, Sato A, Shinke M, Takahashi S, Tobe Y, Takao H, Murayama Y, Umezu M. Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime. J R Soc Interface 2013; 10:20121031. [PMID: 23427094 DOI: 10.1098/rsif.2012.1031] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were compared. The temporal and spatial variations of near-wall velocity at flow impingement delineated its inherent instability at a low Reynolds number. Wall shear stress (WSS) at that site exhibited a combination of temporal fluctuation and spatial divergence. The frequency range of fluctuation was found to exceed significantly that of the heart rate. The high-frequency-fluctuating WSS appeared only during mid-systole and disappeared during late diastole. These results suggested that the flow impingement induced a transition from a laminar regime. This study demonstrated that the hydrodynamic instability of shear layer could not be neglected even at a low Reynolds number. No assumption was found to justify treating the aneurysmal haemodynamics as a fully viscous laminar flow.
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Affiliation(s)
- Takanobu Yagi
- Center for Advanced Biomedical Sciences, Waseda University, Tokyo, Japan.
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9
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Hayashi Y, Yagi T, Tobe Y, Iwabuchi Y, Yamanashi M, Takamura K, Iwasaki K, Umezu M, Ishida T, Nakajima A, Yoshida H, Nishitani K, Ota Y, Sugawara M, Okada Y, Kubo T, Kitahara S. Abstract TMP29: Prediction of Wall-thinning Area in Unruptured Intracerebral Aneurysms by Computational Fluid Dynamics. Stroke 2013. [DOI: 10.1161/str.44.suppl_1.atmp29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Background and purpose]
During a clipping surgery, an unruptured intracerebral aneurysm often presented a spatially-localized red-colored "wall-thinning" area. The wall thinning was believed to be related with the risk of rupture. The present aim is given to investigate the predictability of a wall thinning area using computational fluid dynamics (CFD).
[Method]
We chose 16 unruptured aneurysms (12 MCA, 4 ICA) with clipping surgery and 24 wall-thinning areas were detected from the operation video. CFD study was carried out using patient-specific angiographic data. The wall shear stress (WSS) and the wall pressure were evaluated.
[Results]
The WSS magnitude was found to be uncorrelated with wall thinning. On the other hand, 20 wall-thinning areas (83%) exhibited a presence of “flow impingement”, which was defined to give the spatial variation of the WSS vector to be divergent with the local elevation of the wall pressure. From CFD, 27 flow impingements were detected and classified according to the degree of divergence. Seven impingements are full-divergent and all of them (100%) are located in the wall thinning areas. The remaining 20 impingements were partial-divergent and 13 impingements of them (65%) were located in the wall thinning areas. A classification of full-/partial-divergent flow impingement was statistically significant for the prediction of wall-thinning areas (P<0.01).
[Conclusions]
The full-divergent flow impingement was found to be a reliable predictor of the wall thinning area in unruptured intracerebral aneurysms. The present results demonstrated the malignant nature of flow impingement for promoting the thinning of aneurysmal walls.
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Affiliation(s)
| | - Takanobu Yagi
- Waseda Univ Cntr for Advanced Biomedical Sciences / TWIns, Tokyo, Japan
| | - Yasutaka Tobe
- Waseda Univ Cntr for Advanced Biomedical Sciences / TWIns, Tokyo, Japan
| | - Yuki Iwabuchi
- Waseda Univ Cntr for Advanced Biomedical Sciences / TWIns, Tokyo, Japan
| | - Momoko Yamanashi
- Waseda Univ Cntr for Advanced Biomedical Sciences / TWIns, Tokyo, Japan
| | - Kenji Takamura
- Waseda Univ Cntr for Advanced Biomedical Sciences / TWIns, Tokyo, Japan
| | - Kiyotaka Iwasaki
- Waseda Univ Cntr for Advanced Biomedical Sciences / TWIns, Tokyo, Japan
| | - Mitsuo Umezu
- Waseda Univ Cntr for Advanced Biomedical Sciences / TWIns, Tokyo, Japan
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Goyagi T, Tobe Y, Nishikawa T. Long-term and spatial memory effects of selective β1-antagonists after transient focal ischaemia in rats. Br J Anaesth 2012; 109:399-406. [PMID: 22581807 DOI: 10.1093/bja/aes134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Although various reports have shown that β-antagonists provide neuroprotective effects after cerebral ischaemia, their effect on spatial memory after transient focal ischaemia is not known. We investigated the treatment of β1-antagonists on neurological outcome spatial memory for 1 month after focal cerebral ischaemia in rats. METHODS Male rats randomly received an i.v. infusion of saline 0.5 ml h(-1), esmolol 200 μg kg(-1) min(-1), or landiolol 50 μg kg(-1) min(-1). Infusion was initiated 30 min before middle cerebral artery occlusion and continued for 24 h. The infarct areas in the hippocampus and striatum were measured after the final retention trial and neurological examinations. RESULTS Neurological deficit scores in the landiolol- and esmolol-treated rats were significantly lower than in the control rats at 1, 4, 7, and 11 days after ischaemia (P<0.05). Using the Morris water maze to assess spatial memory, we found that escape latency and swimming path length to the platform were significantly shorter in the landiolol-treated rats, compared with the saline-treated rats at 4 and 11 days after ischaemia (P<0.05). The mean (SD) infarct area was 19.1 (8.0)% in the striatum and 18.6 (10.0)% in the hippocampus of the landiolol-treated rats, and 16.8 (14.0)% and 16.8 (15.0)% in the striatum and hippocampus, respectively, of esmolol-treated rats. This was significantly less than in control rats [striatum 31.7 (14.0)% and hippocampus 29.8 (13.0)%, P<0.05]. CONCLUSIONS The current study indicates that although esmolol and landiolol provided long-term neuroprotection in terms of histological outcome, they had no effect on neurological outcome and spatial memory retention.
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Affiliation(s)
- T Goyagi
- Department of Anaesthesia and Intensive Care Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita-city, Akita 010-8543, Japan.
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Sato K, Kimura T, Nishikawa T, Tobe Y, Masaki Y. Neuroprotective effects of a combination of dexmedetomidine and hypothermia after incomplete cerebral ischemia in rats. Acta Anaesthesiol Scand 2010; 54:377-82. [PMID: 19860751 DOI: 10.1111/j.1399-6576.2009.02139.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Dexmedetomidine and hypothermia are known to reduce neuronal injury following cerebral ischemia. We examined whether a combination of dexmedetomidine and hypothermia reduces brain injury after transient forebrain ischemia in rats to a greater extent than either treatment alone. METHODS Thirty-eight male Sprague-Dawley rats were anesthetized with fentanyl and nitrous oxide in oxygen. Four groups were tested: group C (saline 1 ml/kg, temporal muscle temperature 37.5 degrees C); group H (saline 1 ml/kg, 35.0 degrees C); group D (dexmedetomidine 100 microg/kg, 37.5 degrees C); and group DH (dexmedetomidine 100 microg/kg, 35.0 degrees C). Dexmedetomidine or saline was administered intraperitoneally 30 min before ischemia. Cerebral ischemia was produced by right carotid artery ligation with hemorrhagic hypotension (mean arterial pressure 40 mmHg) for 20 min. Neurologic outcome was evaluated at 24, 48, and 72 h after ischemia. Histopathology was evaluated in the caudate and hippocampus at 72 h after ischemia. RESULTS Neurologic outcome was significantly better in the group DH than the group C (P<0.05), whereas it was similar between the group DH and the groups D or H. Survival rate of the hippocampal CA1 neurons was significantly greater in groups D, H, and DH than group C (P<0.05). Histopathologic injury in the caudate section was significantly less in groups H and DH than group C (P<0.05). CONCLUSION The combination of dexmedetomidine and hypothermia improved short-term neurologic outcome compared with the control group, whereas the combination therapy provided comparable neuroprotection with either of the two therapies alone.
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Affiliation(s)
- K Sato
- Department of Anesthesia and Intensive Care Medicine, Akita University School of Medicine, Akita 010-8543, Japan
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Goyagi T, Nishikawa T, Tobe Y, Masaki Y. The combined neuroprotective effects of lidocaine and dexmedetomidine after transient forebrain ischemia in rats. Acta Anaesthesiol Scand 2009; 53:1176-83. [PMID: 19388884 DOI: 10.1111/j.1399-6576.2009.01976.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [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: 11/26/2022]
Abstract
BACKGROUND We investigated whether coadministration of lidocaine and dexmedetomidine would reduce brain injury following transient forebrain ischemia in rats to a greater extent than either drug alone. METHODS Adult male Sprague-Dawley rats were anesthetized with halothane to maintain normocapnia and normoxia. Rats received subcutaneous injection of saline 1 ml/kg, lidocaine 10 mg/kg, dexmedetomidine 3 microg/kg, or lidocaine 10 mg/kg plus dexmedetomidine 3 microg/kg. Thirty minutes after the drug injection, forebrain ischemia was induced by hemorrhagic hypotension and occlusion of the bilateral carotid arteries, and was confirmed by isoelectric EEG. At the end of 10-min ischemia, rats were reperfused. The same dose of drugs was administered 3, 24, and 48 h after ischemia. Neurological examination was done at 1, 2, and 7 days after ischemia. Seven days after ischemia, the brain was stained with hematoxylin and eosin. We counted ischemic cells in the CA1 hippocampal region, striatum, and cerebral cortex. We also measured extracellular glutamate and norepinephrine concentration in hippocampal CA1 in the four groups. RESULTS As compared with saline-treated rats, rats receiving dexmedetomidine plus lidocaine showed less than neurological deficit scores at 2 and 7 days after ischemia, and had less ischemic cells in the CA1 region. However, administration of dexmedetomidine plus lidocaine did not alter the area under the glutamate concentration curve and norepinephrine concentration during ischemia in the CA1 region, compared with saline-treated rats. CONCLUSIONS Our results suggest coadministration of lidocaine and dexmedetomidine improves the neurological outcome without alteration of glutamate and norepinephrine concentrations during forebrain ischemia in rats.
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Affiliation(s)
- T Goyagi
- Department of Anesthesia and Intensive Care Medicine, Akita University School of Medicine, Akita, Japan.
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Kimura T, Sato K, Nishikawa T, Tobe Y, Masaki Y. Effect of mivazerol, a alpha-agonist, on striatal norepinephrine concentration during transient forebrain ischemia in rats. Acta Anaesthesiol Scand 2008; 52:997-1002. [PMID: 18494845 DOI: 10.1111/j.1399-6576.2008.01683.x] [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: 11/29/2022]
Abstract
BACKGROUND We have previously reported that mivazerol, a alpha(2)-agonist, possibly provides neuroprotection against transient forebrain ischemia in rats. This study was designed to investigate the ability of mivazerol to attenuate ischemia-induced increase in striatal norepinephrine concentration after transient forebrain ischemia in rats. METHODS Male Sprague-Dawley rats, anesthetized with halothane, were assigned to one of three groups (n=10 each); control (C, normal saline 1 ml/kg), mivazerol 20 microg/kg (M20), and 40 microg/kg (M40) groups. Monitored variables included temporal muscle temperature (maintained at 37.5+/-0.1 degrees C), electroencephalogram, systolic/diastolic blood pressure, heart rate, arterial blood gases, and blood glucose concentrations. Thirty minutes after subcutaneous drug administration, forebrain ischemia was induced with hemorrhagic hypotension (systolic arterial pressure: 40-50 mmHg) and bilateral carotid artery occlusion for 10 min, and then the brain was reperfused. Norepinephrine concentration in the interstitial fluids in the striatum was analyzed using in vivo microdialysis in combination with high-performance liquid chromatography. RESULTS Ischemia resulted in a prompt increase in norepinephrine concentrations in the striatum in all groups. However, there were no significant differences in norepinephrine concentrations in the striatum between the three groups at any period. CONCLUSIONS Our results indicate that mivazerol did not attenuate ischemia-induced increase in striatal norepinephrine concentration. This suggests that the possible neuroprotective property of mivazerol is not related to inhibition of norepinephrine release in the brain.
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Affiliation(s)
- T Kimura
- Department of Anesthesia and Intensive Care Medicine, Akita University School of Medicine, Akita, Japan.
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Kimura T, Sato M, Nishikawa T, Tanaka M, Tobe Y, Masaki Y. Neuroprotective effect of mivazerol, an alpha 2-agonist, after transient forebrain ischemia in rats. Acta Anaesthesiol Scand 2005; 49:1117-23. [PMID: 16095453 DOI: 10.1111/j.1399-6576.2005.00794.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND We examined whether mivazerol, an alpha2-agonist, had neuroprotective effects after transient forebrain ischemia in rats. METHODS Male Sprague-Dawley rats, anesthetized with halothane, were assigned to one of four groups (n=10 each): control (C, normal saline) and mivazerol 10 microg/kg (M10), 20 microg/kg (M20) and 40 microg/kg (M40) groups. Thirty minutes after drug administration, forebrain ischemia was induced with hemorrhagic hypotension and bilateral carotid artery occlusion for 10 min, and then the brain was reperfused. The neurologic outcome was evaluated 24 h, 48 h and 7 days after ischemia, followed by histologic evaluation. RESULTS The survival rate during 7 days was significantly lower in group M40 than in groups M10 and M20 (P<0.05). The neurologic outcome was significantly better in groups M10 and M20 than in group M40 7 days after ischemia (P<0.05). The number of intact neurons in hippocampal CA1 was significantly greater in group M20 than in the other groups (P<0.05). Neuronal injury in the neocortex was significantly less in group M20 than in groups C and M40 (P<0.05). CONCLUSIONS Our results suggest that mivazerol, up to 20 microg/kg, provides neuroprotective effects, whereas 40 microg/kg may exaggerate neuronal injury after transient forebrain ischemia in rats.
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Affiliation(s)
- T Kimura
- Department of Anesthesia and Intensive Care Medicine, Akita University School of Medicine, Akita, Japan.
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Sonoda M, Inaba A, Itahashi K, Tobe Y. Synthesis of differentially substituted hexaethynylbenzenes based on tandem Sonogashira and Negishi cross-coupling reactions. Org Lett 2001; 3:2419-21. [PMID: 11463331 DOI: 10.1021/ol016274o] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Synthesis of polyethynyl-substituted aromatic compounds was achieved efficiently by the use of the Negishi cross-coupling reaction, and this method, coupled with the Sonogashira reaction, was applied to the synthesis of differentially substituted hexaethynylbenzenes from chloroiodobenzenes.
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Affiliation(s)
- M Sonoda
- Department of Chemistry, Faculty of Engineering Science, Osaka University, and CREST, Japan Science and Technology Corporation (JST), Toyonaka, Osaka 560-8531, Japan
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Shoji K, Enzan K, Tobe Y, Suzuki M, Yoshioka N. [Role of antigen-antibody reaction in pulmonary hypertensive reaction after antigen challenge]. Masui 1995; 44:1091-6. [PMID: 7474306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Pulmonary arterial pressure, airway pressure, and lung weight increase were studied after antigen (human O-N type erythrocytes) challenge in isolated-perfused sensitized rabbit lungs. To investigate whether these hemodynamic changes are mainly caused by antigen-antibody reaction or by the other mechanisms, we measured changes of pulmonary arterial and airway pressures, and lung weight gain after antigen challenge in perfused nonsensitized rabbit lungs. Thirteen nonsensitized rabbits were divided into 2 groups; in N group (n = 5), antigen was given into Krebs Hanseleit perfusate; in Ab group (n = 8), antibody was given into reservoir 30 min prior to antigen challenge. Pulmonary arterial pressure in Ab group was higher than in N group after antigen challenge. Maximal increase in pulmonary arterial pressure after antigen challenge depended on agglutinin titer of antibody in perfusate (delta Ppa = 0.068 x [titer]-0.146, r2 = 0.929). However, there were no significant differences between the two groups in changes of airway pressure and lung weight gain after antigen challenge. Although agglutinin titer of perfusate in Ab group was higher than our previous study, pulmonary hypertensive reaction to antigen in Ab group was significantly lower. It is concluded that the other mechanism besides antigen-antibody reaction itself can be responsible for hemodynamic changes after antigen challenge.
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Affiliation(s)
- K Shoji
- Department of Anesthesiology, Akita Kumiai General Hospital
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Kakiuchi K, Ue M, Takeda M, Tadaki T, Kato Y, Nagashima T, Tobe Y, Koike H, Ida N, Odaira Y. Antiproliferating polyquinanes. V. Di-and triquinanes involving alpha-methylene or alpha-alkylidene cyclopentanone, cyclopentenone, and gamma-lactone systems. Chem Pharm Bull (Tokyo) 1987; 35:617-31. [PMID: 3594674 DOI: 10.1248/cpb.35.617] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Kobiro K, Tskshsdhi M, Nishikawa N, Kakiuchi K, Tobe Y, Odaira Y. Complexation between novel cyclophane host and polar guests by hydrogen bonding. Tetrahedron Lett 1987. [DOI: 10.1016/s0040-4039(00)96787-x] [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: 12/01/2022]
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Furuyama S, Negishi T, Tobe Y, Takiguchi H. Studies on Ca2+-stimulated adenosine triphosphatase in rat submandibular glands: its distribution and properties. J Dent Res 1975; 54:32-40. [PMID: 234129 DOI: 10.1177/00220345750540013301] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Intracellular distribution and some characteristics of a Ca2+-stimulated adenosine triphosphatase (ATPase) in rat submandibular glands were investigated. This enzyme was activated by calcium alone, and magnesium was not necessary for its activation. Mg2+-stimulated ATPase also was investigated in the same enzyme preparations.
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Ikeda R, Kobayashi I, Ema S, Tobe Y, Takeuchi T. Intercellular distribution and partial purification of phosphoprotein in bovine parotid gland. J Nihon Univ Sch Dent 1973; 15:31-7. [PMID: 4518914 DOI: 10.2334/josnusd1959.15.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Terakado M, Namiki Y, Takahashi H, Otake S, Tobe Y. Effects of arsenite on incorporation of mevalonate-2-14C into squalene-14C in rabbit dental pulp. J Nihon Univ Sch Dent 1973; 15:27-30. [PMID: 4517364 DOI: 10.2334/josnusd1959.15.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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