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Matsune H, Ono T, Yoshida R, Yamamoto T, Kishida M. Glutathione-responsive Nanoparticle Consisting of an Amino-functionalized Silsesquioxane Network Cross-linked by Zinc Ions for a Promising Drug Carrier. CHEM LETT 2019. [DOI: 10.1246/cl.190353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hideki Matsune
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Moto-oka, Fukuoka 819-0395, Japan
| | - Tomoya Ono
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Moto-oka, Fukuoka 819-0395, Japan
| | - Ryoya Yoshida
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Moto-oka, Fukuoka 819-0395, Japan
| | - Tsuyoshi Yamamoto
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Moto-oka, Fukuoka 819-0395, Japan
| | - Masahiro Kishida
- Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Moto-oka, Fukuoka 819-0395, Japan
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Tzoneva R, Uzunova V, Apostolova S, Krüger-Genge A, Neffe AT, Jung F, Lendlein A. Angiogenic potential of endothelial and tumor cells seeded on gelatin-based hydrogels in response to electrical stimulations. Clin Hemorheol Microcirc 2017; 64:941-949. [PMID: 27792001 DOI: 10.3233/ch-168040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Angiogenesis is one of the key processes during development, wound healing and tumor formation. Prerequisite for its existence is the presence of endogenous electrical fields (EFs) generated by active ion transport across polarized epithelia and endothelia, and appearance of the transcellular potentials. During angiogenesis cellular factor as endothelial growth factor (VEGF), synthesis of adhesive proteins and membrane metalloproteinases (MMPs) govern the angiogenic response to different external stimuli as biomaterials interactions and/or exogenous EF. Gelatin-based hydrogels with elasticities comparable to human tissues have shown to influence cell behavior as well as cell attachment, protein synthesis, VEGF and MMP's production after the application of EF. Gelatin-based matrices with 3 (G10_LNCO3), 5 (G10_LNCO5), and 8 (G10_LNCO8) fold excess of isocyanate groups per mol of amine groups present in gelatin were used. Human umbilical endothelial cells (HUVEC) (Lonza Basel, Switzerland) and highly invasive breast cancer MDA-MB-231 cells (ATCC®HTB-26TM) were used. For an estimation of the amount of VEGF released from cells a commercially available VEGF ELISA (Thermo Fisher Scientific, Germany) kit was used. Fibronectin (FN) enzyme immunoassay (EIA) was used to analyze the secreted amount of FN by cells seeded on the materials. Secreted MMPs were analyzed by zymography. Gelatin-based hydrogels attracted HUVEC adhesion and diminished the adhesion of MDA-MB-231 cells. The applied direct current (DC) EF induced an almost 5-fold increase in VEGF production by HUVEC seeded on gelatin-based hydrogels, while in contrast, the applied EF decreased the production of VEGF by cancer cells. FN synthesis was elevated in HUVEC cells seeded on gelatin-based materials in comparison to FN synthesis by cancer cells. HUVEC seeded on gelatin hydrogels showed an expression mainly of MMP-2. The application of EF increased the production of MMP-2 in HUVEC seeded on gelatin materials. In contrast, for MDA-MB-231 the production of MMPs on gelatin materials was lower compared to control materials. With the application of EF the levels of MMP-9 decreased but MMP-2 expression raised significantly for gelatin materials. Overall, the results showed that studied gelatin materials suppressed attachment of cancerous cells, as well as suppressed their angiogenic potential revealed by decreased VEGF and MMP production. Thus, this study approved gelatin-based hydrogels with proper elasticity characteristics and different degradation behavior as useful matrices for use in vascular tissue regeneration or in restriction of tumor growth after tumor resection.
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Affiliation(s)
- Rumiana Tzoneva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Veselina Uzunova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Sonia Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Anne Krüger-Genge
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz Zentrum Geesthacht, Teltow, Germany
| | - Axel T Neffe
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz Zentrum Geesthacht, Teltow, Germany.,Helmholtz Virtual Institute - Multifunctional Biomaterials for Medicine, Teltow and Berlin, Germany
| | - Friedrich Jung
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz Zentrum Geesthacht, Teltow, Germany.,Helmholtz Virtual Institute - Multifunctional Biomaterials for Medicine, Teltow and Berlin, Germany
| | - Andreas Lendlein
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz Zentrum Geesthacht, Teltow, Germany.,Helmholtz Virtual Institute - Multifunctional Biomaterials for Medicine, Teltow and Berlin, Germany
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Zimmermann S, Scheeder C, Zimmermann PK, Bogsnes A, Hansson M, Staby A, Hubbuch J. High-throughput downstream process development for cell-based products using aqueous two-phase systems (ATPS) - A case study. Biotechnol J 2016; 12. [PMID: 27883271 DOI: 10.1002/biot.201600587] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/19/2016] [Accepted: 11/23/2016] [Indexed: 01/27/2023]
Abstract
The availability of preparative-scale downstream processing strategies for cell-based products presents a critical juncture between fundamental research and clinical development. Aqueous two-phase systems (ATPS) present a gentle, scalable, label-free, and cost-effective method for cell purification, and are thus a promising tool for downstream processing of cell-based therapeutics. Here, the application of a previously developed robotic screening platform that enables high-throughput cell partitioning analysis in ATPS is reported. In the present case study a purification strategy for two model cell lines based on high-throughput screening (HTS)-data and countercurrent distribution (CCD)-modeling, and validated the CCD-model experimentally is designed. The obtained data are shown an excellent congruence between CCD-model and experimental data, indicating that CCD-models in combination with HTS-data are a powerful tool in downstream process development. Finally, the authors are shown that while cell cycle phase significantly influences cell partitioning, cell type specific differences in surface properties are the main driving force in charge-dependent separation of HL-60 and L929 cells. In order to design a highly robust purification process it is, however, advisable to maintain constant growth conditions.
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Affiliation(s)
- Sarah Zimmermann
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Science, Section IV: Biomolecular Separation Engineering (MAB), Karlsruhe, Germany
| | - Christian Scheeder
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Science, Section IV: Biomolecular Separation Engineering (MAB), Karlsruhe, Germany
| | - Philipp K Zimmermann
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Science, Section IV: Biomolecular Separation Engineering (MAB), Karlsruhe, Germany
| | - Are Bogsnes
- Novo Nordisk A/S, Biopharm Purification Development & Virology, Gentofte, Denmark
| | | | - Arne Staby
- Novo Nordisk A/S, CMC Project Planning & Management, Bagsvaerd, Denmark
| | - Jürgen Hubbuch
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Science, Section IV: Biomolecular Separation Engineering (MAB), Karlsruhe, Germany
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Ghenim L, Kaji H, Hoshino Y, Ishibashi T, Haguet V, Gidrol X, Nishizawa M. Monitoring impedance changes associated with motility and mitosis of a single cell. LAB ON A CHIP 2010; 10:2546-50. [PMID: 20676434 DOI: 10.1039/c004115g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a device enabling impedance measurements that probe the motility and mitosis of a single adherent cell in a controlled way. The micrometre-sized electrodes are designed for adhesion of an isolated cell and enhanced sensitivity to cell motion. The electrode surface is switched electro-chemically to favour cell adhesion, and single cells are attracted to the electrode using positive dielectrophoresis. Periods of linear variation in impedance with time correspond to the motility of a single cell adherent to the surface estimated at 0.6 μm h(-1). In the course of our study we observed the impedance changes associated with mitosis of a single cell. Electrical measurements, carried out concomitantly with optical observations, revealed three phases, prophase, metaphase and anaphase in the time variation of the impedance during cell division. Maximal impedance was observed at metaphase with a 20% increase of the impedance. We argue that at mitosis, the changes detected were due to the charge density distribution at the cell surface. Our data demonstrate subtle electrical changes associated with cell motility and for the first time with division at the single-cell level. We speculate that this could open up new avenues for characterizing healthy and pathological cells.
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Affiliation(s)
- Lamya Ghenim
- CEA, iRTSV, Laboratoire Biopuces, 17 Rue des Martyrs, 38054 Grenoble, France.
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Bhagat AAS, Bow H, Hou HW, Tan SJ, Han J, Lim CT. Microfluidics for cell separation. Med Biol Eng Comput 2010; 48:999-1014. [DOI: 10.1007/s11517-010-0611-4] [Citation(s) in RCA: 440] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 04/01/2010] [Indexed: 12/19/2022]
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Flowers HM, Sharon N. Glycosidases--properties and application to the study of complex carbohydrates and cell surfaces. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 48:29-95. [PMID: 367104 DOI: 10.1002/9780470122938.ch2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Wang E, Reid B, Lois N, Forrester JV, McCaig CD, Zhao M. Electrical inhibition of lens epithelial cell proliferation: an additional factor in secondary cataract? FASEB J 2005; 19:842-4. [PMID: 15764648 PMCID: PMC1459287 DOI: 10.1096/fj.04-2733fje] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cataract is the most common cause of blindness but is at least curable by surgery. Unfortunately, many patients gradually develop the complication of posterior capsule opacification (PCO) or secondary cataract. This arises from stimulated cell growth within the lens capsule and can greatly impair vision. It is not fully understood why residual lens epithelial cell growth occurs after surgery. We propose and show that cataract surgery might remove an important inhibitory factor for lens cell growth, namely electric fields. The lens generates a unique pattern of electric currents constantly flowing out from the equator and entering the anterior and posterior poles. We show here that cutting and removing part of the anterior capsule as in cataract surgery significantly decreases the equatorial outward electric currents. Application of electric fields in culture inhibits proliferation of human lens epithelial cells. This inhibitory effect is likely to be mediated through a cell cycle control mechanism that decreases entry of cells into S phase from G1 phase by decreasing the G1-specific cell cycle protein cyclin E and increasing the cyclin-Cdk complex inhibitor p27kip1. Capsulorrhexis in vivo, which reduced endogenous lens electric fields, significantly increased LEC growth. This, together with our previous findings that electric fields have significant effects on the direction of lens cell migration, points to a controlling mechanism for the aberrant cell growth in posterior capsule opacification. A novel approach to control growth of lens epithelial cells using electric fields combined with other controlling mechanisms may be more effective in the prevention and treatment of this common complication of cataract surgery.
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Affiliation(s)
| | | | - Noemi Lois
- Department of Ophthalmology, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - John V. Forrester
- Department of Ophthalmology, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | | | - Min Zhao
- School of Medical Sciences and
- Corresponding author: Min Zhao, School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, UK. E-mail:
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Effect of interferon-α 2b on cells from human embryonic nerve tissue in the early stages of neurogenesis. NEUROPHYSIOLOGY+ 2004. [DOI: 10.1007/s11062-005-0025-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bai H, McCaig CD, Forrester JV, Zhao M. DC electric fields induce distinct preangiogenic responses in microvascular and macrovascular cells. Arterioscler Thromb Vasc Biol 2004; 24:1234-9. [PMID: 15130919 DOI: 10.1161/01.atv.0000131265.76828.8a] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Electrical stimulation induces significant angiogenesis in vivo. We have shown recently that electrical stimulation induces directional migration, reorientation, and elongation of macrovascular endothelial cells. Because angiogenesis occurs mainly in the microvasculature, we have extended this observation to include human microvascular endothelial cells (HMEC-1s) and compared the responses with that of vascular fibroblasts and smooth muscle cells and human umbilical vein endothelial cells. METHODS AND RESULTS Four types of vascular cells were cultured in electric fields (EFs). Dynamic cell behaviors were recorded and analyzed with an image analyzer. EFs of 150 to 400 mV/mm induced directed migration, reorientation, and elongation of all the vascular cells. HMEC-1s showed the greatest directional migration (migration rate of 11 microm/h and directedness of 0.35 at 200 mV/mm). Most intriguingly, HMEC-1s migrated toward the cathode, whereas the other cell types migrated toward the anode. CONCLUSIONS Endothelial cells derived from angiogenic microvascular as opposed to nonangiogenic macrovascular tissues were more responsive to electrical stimulation. This intriguing directional selectivity indicates that a DC electrical signal as a directional cue may be able to play a role in the spatial organization of vascular structure.
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Affiliation(s)
- Huai Bai
- Department of Biomedical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, UK
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Zhao M, Bai H, Wang E, Forrester JV, McCaig CD. Electrical stimulation directly induces pre-angiogenic responses in vascular endothelial cells by signaling through VEGF receptors. J Cell Sci 2003; 117:397-405. [PMID: 14679307 PMCID: PMC1459284 DOI: 10.1242/jcs.00868] [Citation(s) in RCA: 276] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Controlling angiogenesis is crucial. Growth factors and cytokines are key regulators but a full understanding remains elusive. Endogenous electrical potential differences exist within and around the vasculature, both in relation to blood flow and in situations where active angiogenesis occurs, such as wound healing, development and tumor growth. Recent work shows that electrical stimulation induces significant angiogenesis in vivo, through enhanced vascular endothelial growth factor (VEGF) production by muscle cells. We report that applied electric fields (EFs) of small physiological magnitude directly stimulate VEGF production by endothelial cells in culture without the presence of any other cell type. EFs as low as 75-100 mV mm-1 (1.5-2.0 mV across an endothelial cell) directed the reorientation, elongation and migration of endothelial cells in culture. These pre-angiogenic responses required VEGF receptor activation and were mediated through PI3K-Akt and Rho-ROCK signaling pathways, resulting in reorganization of the actin cytoskeleton. This indicates that endogenous EFs might play a role in angiogenesis in vivo by stimulating the VEGF receptor signaling pathway, to induce key pre-angiogenic responses. In addition, it raises the feasibility of using applied EFs to initiate and guide angiogenesis through direct effects on endothelial cells.
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Affiliation(s)
- Min Zhao
- Department of Biomedical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK.
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Abstract
Capillary electrophoresis (CE) of erythrocytes from different sources under various conditions is reported in this paper. It was found that erythrocyte samples from sheep, duck, and human showed characteristic and reproducible elution peaks, and that the retention times of A-, B-, AB-, and O-type erythrocytes from human blood were distinctively different; even subtle differences, among individuals with the same blood type could be detected by CE. A strictly linear correlation was obtained between the peak area and the amount of human erythrocyte over a range of 4.8 x 10(2)-1.9 x 10(4) cells (r=0.999), indicating that CE could be used for rapid and accurate quantification of erythrocytes. Using this CE protocol, the decrease of the surface electrical charge of erythrocyte during storage was confirmed. Therefore, this work demonstrated that CE could be a useful alternative for characterizing and quantifying erythrocytes or other cells.
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Affiliation(s)
- Wan-Hua Lu
- Institute of Biotechnology, Fuzhou University, Gong-Ye-Ru Road 523, Fuzhou, Fujian Province 350002, People's Republic of China
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Zhao M, Forrester JV, McCaig CD. A small, physiological electric field orients cell division. Proc Natl Acad Sci U S A 1999; 96:4942-6. [PMID: 10220398 PMCID: PMC21796 DOI: 10.1073/pnas.96.9.4942] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We report on an observation that the orientation of cell division is directed by small, applied electric fields (EFs). Cultured human corneal epithelial cells were exposed to a direct-current EF of physiological magnitude. Cells divided while attached to the culture dish, and most did so with a cleavage plane perpendicular to the EF vector. There are many instances in which cell divisions in vivo occur in the presence of direct-current physiological EF, for example, during embryonic morphogenesis, neuronal and epithelial differentiation, wound healing, or tumor formation. Endogenous physiological EFs may play important roles in some or all of these processes by regulating the axis of cell division and, hence, the positioning of daughter cells.
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Affiliation(s)
- M Zhao
- Department of Biomedical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland
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Walter H, Al-Romaihi FA, Krob EJ, Seaman GV. Fractionation of K-562 cells on the basis of their surface properties by partitioning in two-polymer aqueous-phase systems. CELL BIOPHYSICS 1987; 10:217-32. [PMID: 2446768 DOI: 10.1007/bf02797342] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The K-562 cell line is a culture of human leukemia stem cells originally derived from a patient with chronic myelogenous leukemia in blast crisis. We have subjected such cells, in the log phase of growth, to countercurrent distribution in a charge-sensitive dextran-polyethylene glycol aqueous-phase system, a method that fractionates cells on the basis of subtle differences in their surface properties, and found that: (1) The cell population is heterogeneous since it is composed of cells with different partition ratios. (2) There is a correlation between increasing cell partition ratios and increasing cell electrophoretic mobilities. (3) Cells under different parts of the distribution curve have dissimilar ratios of cells in different parts of the cell cycle, a phenomenon that may, at least partially, be the basis for the subfractionation of these cells. There is a clear tendency for cells in G0 + G1 + early S to decrease and for those in late S + G2 + M to increase with increasing partition ratios. (4) Sialic acid is a major surface charge component of the cells as evidenced by a dramatic drop in their partition ratios after treatment with neuraminidase.
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Affiliation(s)
- H Walter
- Laboratory of Chemical Biology, Veterans Administration Medical Center, Long Beach, CA 90822
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Sherbet GV, Lakshmi MS. Isoelectric equilibrium properties of normal and malignant cells and biological macromolecules. INTERNATIONAL REVIEW OF CYTOLOGY 1986; 102:29-52. [PMID: 3533830 DOI: 10.1016/s0074-7696(08)61273-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Gomariz-Zilber E, Wioland M, Milhaud G. Cell surface analyses of the age-dependent changes in the electrokinetic properties of human peripheral blood lymphocytes. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1985; 35:352-62. [PMID: 3987096 DOI: 10.1016/0090-1229(85)90096-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The age-dependent changes in the surface electrical charge of human peripheral blood lymphocytes were analyzed by establishing the differences between the surface density of four types of chemical groups on lymphocytes isolated from the blood of individuals of increasing ages. Similar determinations were carried out on cord blood lymphocytes which were shown previously to exhibit either a low or a high electrical charge density reflected in the experimentally determined parameter, the anodic electrophoretic mobility (EPM), differing by about 30%. The surface density of carboxyl group of N-acetylneuraminic acid (NANA), protein side chain epsilon-amino groups, and phosphate groups were different for the two subpopulations of CBL. Differences were also observed between the surface density of these groups on the two subpopulations of CBL and the lymphocytes of older individuals, with the exception of carboxyl groups. In some experiments on lymphocytes from adults, the carboxyls of NANA were much more numerous on nearly 1% of the cells.
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Changes in surface charge of mouse neuroblastoma cells during growth and morphological differentiation of the cell population. NEUROPHYSIOLOGY+ 1985. [DOI: 10.1007/bf01052944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Lynn D, Hink W. Infection of synchronized TN-368 cell cultures with alfalfa looper nuclear polyhedrosis virus. J Invertebr Pathol 1978. [DOI: 10.1016/0022-2011(78)90167-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Brabec V, Christian SD, Dryhurst G. Potential and structure controlled interfacial behavior of uracil derivatives. Biophys Chem 1978; 7:253-68. [PMID: 623867 DOI: 10.1016/0301-4622(78)85002-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The adsorption and related interfacial behavior of uracil, various methylated uracil derivatives, uridine, uridine-5'-monophosphate and uridine-3'5'-cyclic monophosphate has been studied by surface electrochemical measurements at a mercury electrode. All uracil derivatives exhibit an initial "dilute" adsorption region where the virtually flat uracil residue is absorbed flat on the electrode surface. In the case of uracil and its methylated derivatives the area occupied by one molecule is about 60-70 A2. Uracil, thymine and 1,5-dimethyluracil exhibit a second adsorption region where they rearrange on the surface and adopt a perpendicular orientation and occupy about 40 A2 per molecule. In this perpendicular orientation the uracils are bound to the electrode through the N(3)-H or perhaps N(1)-H functions in a manner similar to their Watson-Crick bonding in nucleic acids. When in the perpendicular orientation the adsorbed molecules undergo extensive stacking (association) interactions, again similar to those observed between adjacent bases in nucleic acids. The ability of a uracil derivative to undergo a surface reorientation is critically dependent on electrode potential, bulk-solution concentration and molecular structure.
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Josefowicz JY, Ware BR, Griffith AL, Catsimpoolas N. Physical heterogeneity of mouse thymus lymphocytes. Life Sci 1977; 21:1483-8. [PMID: 303734 DOI: 10.1016/0024-3205(77)90203-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Ray PK. Bacterial neuraminidase and altered immunological behavior of treated mammalian cells. ADVANCES IN APPLIED MICROBIOLOGY 1977; 21:227-67. [PMID: 403747 DOI: 10.1016/s0065-2164(08)70043-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Johnsen S, Stokke T, Prydz H. HeLa cell plasma membranes. Changes in membrane protein composition during the cell cycle. Exp Cell Res 1975; 93:245-51. [PMID: 49274 DOI: 10.1016/0014-4827(75)90447-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Redmann K, Jenssen HL, Köhler HJ. Experimental and functional changes in transmembrane potential and zeta potential of single cultured cells. Exp Cell Res 1974; 87:281-9. [PMID: 4606541 DOI: 10.1016/0014-4827(74)90482-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Steinberg MS, Armstrong PB, Granger RE. On the recovery of adhesiveness by trypsin-dissociated cells. J Membr Biol 1973; 13:97-128. [PMID: 4205052 DOI: 10.1007/bf01868223] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Walter H, Eriksson G, Taube O, Albertsson PA. Countercurrent distribution and multiple sedimentation of Chlorella pyrenoidosa during its life cycle. Exp Cell Res 1973; 77:361-6. [PMID: 4570357 DOI: 10.1016/0014-4827(73)90589-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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32
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Sherbet GV, Lakshimi MS, Rao KV. Characterisation of ionogenic groups and estimation of the net negative electric charge on the surface of cells using natural pH gradients. Exp Cell Res 1972; 70:113-23. [PMID: 4109349 DOI: 10.1016/0014-4827(72)90188-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Shank BB, Burki HJ. Surface charge and cell volume of synchronized mouse lymphoblasts (L5178-Y). J Cell Physiol 1971; 78:243-50. [PMID: 5167850 DOI: 10.1002/jcp.1040780211] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Glick MC, Gerner EW, Warren L. Changes in the carbohydrate content of the KB cell during the growth cycle. J Cell Physiol 1971; 77:1-5. [PMID: 5546176 DOI: 10.1002/jcp.1040770102] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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