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001-es BibID:	BIBFORM004938
Első szerző:	Balkay László (biofizikus)
Cím:	Flow cytometric determination of intracellular free potassium concentration / Balkay, L., Marian, T., Emri, M., Krasznai, Z., Tron, L.
Dátum:	1997
ISSN:	0196-4763
Megjegyzések:	A flow cytometric assay has been developed for determination of intracellular free potassium concentration ([K+]i). Investigated cells, loaded with the fluorescent pH indicator 2',7bis-(2-carboxyethyl)-5(and-6)-carboxyfluorescein (BCECF), are incubated in the presence of nigericin, and the intracellular pH is measured. The ionophore maintains the same ratio value [H+]/[K+] on both sides of the cytoplasmic membrane, so [K+]i can be evaluated from the measured intracellular pH (pHi) and the known parameters of the buffer. Application of the method revealed that the intracellular potassium concentration is significantly higher in lymphocytes than in proliferating cells of HUT-78, U266, and JY cell lines. A surprisingly low (60 mM) [K+]i concentration was observed with sperm cells of common carp. This method allows measurements on individual cells, provides data of excellent statistics, and still does not require large amounts of material. These features offer remarkable advantages over other techniques used for intracellular K+ measurements, such as steady-state fluorescence, atom absorption photometry, or energy-dispersive x-ray analysis.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban analysis Animal Biophysics Buffers Cell Line Cells diagnostic use Dyes Flow Cytometry Fluorescein Fluoresceins Fluorescence Fluorescent Dyes Human Hungary Hydrogen-Ion Concentration Ionophores Lymphocytes metabolism Mice Nigericin Potassium Rats
Megjelenés:	Cytometry. - 28 : 1 (1997), p. 42-49. -
További szerzők:	Márián Teréz (1950-) (radiobiológus) Emri Miklós (1962-) (fizikus) Krasznai Zoltán (1950-) (biofizikus) Trón Lajos (1941-) (biofizikus)
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001-es BibID:	BIBFORM004948
Első szerző:	Márián Teréz (radiobiológus)
Cím:	Role of extracellular and intracellular pH in carp sperm motility and modifications by hyperosmosis of regulation of the Na+/H+ exchanger / Marian, T., Krasznai, Z., Balkay, L., Emri, M., Tron, L.
Dátum:	1997
ISSN:	0196-4763
Megjegyzések:	Recently developed flow cytometric methods (Tron et al.: Mol Immunol 27:1307-1311, 1990) to measure the intracellular pH (pHi) and intracellular potassium concentration in mammalian cells by using the fluorescent pH-indicator dye 2',7bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF) were adopted for measuring these parameters in carp sperm. The intracellular potassium concentration of the carp sperm was 62.4 +/- 5.3 mM. This is very similar to the potassium concentration of the seminal plasma (87 +/- 16 mM), and it suggests a depolarized state of the sperm cell in the semen. An average pHi value of 7.06 +/- 0.11 was obtained by measuring sperm samples taken from ten animals. Changes in the ionic composition of the environment did not alter pHi. Sperm motility was initiated by transferring the cells to an environment of 110 mOsm osmolality. This hypoosmotic shock induced fast changes in the membrane structure that could be reversed by restoring physiologic osmolality. Activation was accompanied by a fast alkalinization of the sperm cells. This pH change was amiloride sensitive, suggesting the involvement of the Na+/H+ exchanger in the activation process. Alkalinization of acid-loaded sperm cells depended on the osmolality of the environment. Equilibrium pHi of these cells in hyperosmotic buffers was substantially lower relative to cells in an isoosmotic environment. Effects of the extracellular and intracellular pH on carp sperm motility were also examined. Extracellular pH below 5.5 abolished sperm motility completely. Alkaline extracellular pH did not alter the duration of sperm motility even at extreme values (pHe = 9.6). Duration of the flagellar motion did not depend on the pHi between values of 6.5 and 8.5; however, it was significantly reduced both below and above this range. No motility was observed below pHi = 6.0 or above pHi = 9.5 with a 10 min incubation time at these pH values prior to activation. Effects of the extracellular and intracellular pH on sperm motility were partially reversible.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Amiloride Animal Buffers Carps Cell Membrane Permeability Cells chemistry cytology Dyes Extracellular Space Flow Cytometry Fluorescein Fluoresceins Fluorescent Dyes Hungary Hydrogen-Ion Concentration Intracellular Fluid Light Male methods Motion Osmolar Concentration physiology Potassium Scattering,Radiation Semen Sodium-Hydrogen Antiporter Sperm Motility Spermatozoa Support,Non-U.S.Gov't egyetemen (Magyarországon) készült közlemény
Megjelenés:	Cytometry. - 27 : 4 (1997), p. 374-382. -
További szerzők:	Krasznai Zoltán (1950-) (biofizikus) Balkay László (1963-) (biofizikus) Emri Miklós (1962-) (fizikus) Trón Lajos (1941-) (biofizikus)
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001-es BibID:	BIBFORM004668
Első szerző:	Márián Teréz (radiobiológus)
Cím:	Membrane permeability changes induce hyperpolarization in transformed lymphoid cells under high-density culture conditions / Marian, T., Balkay, L., Krasznai, Z., Tron, L.
Dátum:	2000
Megjegyzések:	Membrane potential changes in cells from the human lymphoid B cell line, JY, evoked by increasing cell density in culture were investigated, as data published on other cell types are controversial. An attempt was also made to clear the underlying mechanism. METHODS: Nonadherent JY cells were isolated from high-density plateau-phase cultures (type A cells), medium-density log-phase cultures (type B cells), and low-density lag-phase cultures (type C cells). They were analyzed for transmembrane potential, intracellular free concentration of potassium and sodium, membrane permeability for monovalent cations, cell cycle distribution by measuring DNA content, and glucose uptake. RESULTS: C type cells proved to be relatively depolarized (-41 +/- 3 mV) and cells obtained from the highest density cultures hyperpolarized (-60 +/- 3 mV). Intracellular concentrations ([K](i) = 92-97 mM and [Na](i) = 34-35 mM) were almost identical for each type of cell. The sodium/potassium permeability constant ratio in the A and C type of cells was 0.047 and 0.094, respectively. High-density culture conditions resulted in a pronounced G(1)-phase arrest. CONCLUSIONS: Differences in the membrane potential values induced by high-density culture conditions were maintained by changes in the membrane permeability for the monovalent cations.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban B-Lymphocytes Cations,Monovalent Cell Count Cell Culture Cell Cycle Cell Division Cell Line Cell Membrane Permeability Cells Cells,Cultured Dna Evoked Potentials Flow Cytometry Fludeoxyglucose F 18 Glucose Human Hungary Membrane Potentials metabolism methods physiology Potassium Sodium Support,Non-U.S.Gov't Tumor Cells,Cultured
Megjelenés:	Cytometry. - 41 : 3 (2000), p. 186-192. -
További szerzők:	Balkay László (1963-) (biofizikus) Krasznai Zoltán (1950-) (biofizikus) Trón Lajos (1941-) (biofizikus)
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