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The Emergence of “Magnetic and Fluorescent” Multimodal Nanoparticles as Contrast Agents in Bioimaging
Published in Wolfgang Sigmund, Hassan El-Shall, Dinesh O. Shah, Brij M. Moudgil, Particulate Systems in Nano- and Biotechnologies, 2008
P. Sharma, A. Singh, S.C. Brown, G.A. Walter, S. Santra, S.R. Grobmyer, E.W. Scott, B.M. Moudgil
The overall size of the construct after lipid modification was about 10 nm, which is significantly less than other nanoparticulate contrast agents.40,212 The multimodal character and the biological specificity were demonstrated by specific labeling of human umbilical vein endothelial cells in vitro. A similar multimodal nanoparticle construct was bioconjugated with annexin A5 and used for cellular labeling. Annexin A5 binds with high affinity to phosphatidylserine, which is asymmetrically distributed PS at the outer monolayer of the cell membrane of apoptotic cells.213 The specific targeting ability of these particles was demonstrated in vitro using a T lymphoma cell line. Strong signal enhancement from apoptotic labeled cells using MR and fluorescence was detected.
Intravascular Radiation Detectors to Detect Vulnerable Atheroma in the Coronary Arteries
Published in Robert J. Gropler, David K. Glover, Albert J. Sinusas, Heinrich Taegtmeyer, Cardiovascular Molecular Imaging, 2007
Daniel Pryma, Bradley E. Patt, H. William Strauss
Many atheromas are not visible angiographically and so alternative approaches have been advocated to detect these lesions. Because a key feature of progressive atheroma is inflammation, a number of radionuclide approaches have focused on identifying specific attributes of inflammation. Cells in the lesion are activated and have markedly increased metabolic rates. Glucose is their major metabolic substrate (especially for macrophages), which is obtained from exogenous glucose in the extracellular fluid. Laboratory studies demonstrate that these cells concentrate the glucose analog 18F-fluorodeoxyglucose (18FDG). Macrophages attracted to the lesion have increased expression of receptors on their surface. Radiolabeled peptides localizing in these receptors, such as MCP-1, are found in higher concentration at sites of inflammation. In a similar fashion, there is increased expression of integrin receptors (α2β3) at the lesion site, which can be identified by peptides that recognize these receptors. Inflammation damages and frequently leads to the death of cells responding to the noxious stimulus, often by apoptosis. Therefore, markers of apoptosis, such as radiolabeled annexin V, localize in regions of inflammation.
Analysis of Single Cells Using Lab-on-a-Chip Systems
Published in Frances S. Ligler, Jason S. Kim, The Microflow Cytometer, 2019
One of the most important applications for flow cytometry in the area of cancer research is induction of apoptosis in tumor cells. Upon induction of apoptosis, phosphatidylserine (PS), a membrane constituent that is actively confined to the inner leaflet of the cell membrane becomes displayed on the outer leaflet of the membrane. Annexin-V is a member of the family of calcium- and phospholipidbinding proteins with high affinity for PS and can be used as a sensitive probe for PS. The measurement of annexin-V binding to the cell surface can easily be performed in conjunction with the live cell marker calcein, which is a specific indicator for cells with an intact membrane.10
Cellular and biochemical antileukemic mechanisms of the meroterpenoid Oncocalyxone A
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Aline Borba Sbardelotto, Francisco Washington Araújo Barros-Nepomuceno, Bruno Marques Soares, Bruno Coêlho Cavalcanti, Rayran Walter Ramos de Sousa, Marcília Pinheiro da Costa, Otília Deusdênia Loiola Pessoa, Cláudia Pessoa, Paulo Michel Pinheiro Ferreira
Phosphatidylserine externalization was demonstrated by flow cytometry after PS staining with annexin V (Krysko et al. 2008). Cells were washed twice with cold PBS and then suspended in 135 µl PBS with 5 µl 7-amino-actinomycin D (7-AAD) and 10 µl annexin V-PE (Guava Nexin Assay Kit). The cells were vortexed and incubated for 20 min at room temperature (25°C) in the dark. Subsequently, cells were analyzed using flow cytometry (EasyCyte from Guava TechnologiesTM). Annexin V is a phospholipid-binding protein that has a high affinity for PS. A non-permeant dye 7-AAD was used to indicate membrane integrity. Fluorescence of annexin V-PE was measured at 583 nm (yellow fluorescence) and 7-AAD at 680 nm (red fluorescence) (Vermes et al. 1995). Results were expressed as % early and late apoptotic cells and necrotic cells.
Application of molecular imaging technology in neurotoxicology research
Published in Journal of Environmental Science and Health, Part C, 2018
Xuan Zhang, Qi Yin, Marc Berridge, Che Wang
One of the earliest markers of neurons that are undergoing apoptosis is the externalization of phosphatidylserine (PS), one of the four major phospholipids that makes up the cell membrane, from the intracellular to the extracellular side of the plasma membrane.[19–23] Surrounding normal cells and macrophages can identify the redistribution of PS as a signal for phagocytizing and digesting the components of the apoptotic cells.[24–26] As annexin-V binds to PS with high affinity and specificity, annexin V that is labeled with different radionuclides is a promising tracer for in vivo detection of cells that are undergoing programed cell death.[21,23,25,27,28]
Comparison of the adhesion and endocytosis of calcium oxalate dihydrate to HK-2 cells before and after repair by Astragalus polysaccharide
Published in Science and Technology of Advanced Materials, 2019
Jin Han, Da Guo, Xin-Yuan Sun, Jian-Min Wang, Jian-Ming Ouyang, Bao-Song Gui
In general, PS is located inside the cell membrane. At the early stage of apoptosis, PS can be turned from the inner side to the surface of the cell membrane. Phospholipid-binding protein V (annexin V) is a calcium-dependent phospholipid-binding protein that has a high degree of binding with PS. Therefore, annexin V can be used as a probe to detect the content of PS exposed on the cell membrane [5].