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001-es BibID:	BIBFORM004945
Első szerző:	Heijn, Marc
Cím:	Anthracyclines modulate multidrug resistance protein (MRP) mediated organic anion transport / Marc Heijn, Jan H. Hooijberg, George L. Scheffer, Gábor Szabó, Hans V. Westerhoff, Jan Lankelma
Dátum:	1997
ISSN:	0005-2736
Megjegyzések:	We studied the ATP-dependent uptake of dinitrophenyl-glutathione (GS-DNP) into plasma membrane vesicles derived from parental GLC4 cells and from multidrug resistant GLC4/ADR cells. The latter have a high expression of the multidrug resistance protein (MRP). Uptake of GS-DNP into membrane vesicles from GLC4/ADR cells was highly stimulated by the addition of ATP, compared to the uptake into membrane vesicles from GLC4 cells. This ATP-dependent uptake into membrane vesicles from GLC4/ADR cells was saturable with a Km of 1.2 +/- 0.2 microM and a Vmax of 560 +/- 80 pmol/mg prot./min. ATP stimulated GS-DNP uptake with a Km of 187 +/- 4 microM. This uptake was specifically inhibited by a polyclonal serum raised against a fusion protein containing a segment of MRP. The ATP-dependent uptake of GS-DNP was not only inhibited by organic anions, such as oxidized glutathione (GSSG), methotrexate (MTX) and some bile acids, but also by non-anionic natural product drugs, such as anthracyclines, vinca alkaloids and etoposide (VP-16). Uptake of GSSG and MTX into membrane vesicles from GLC4/ADR cells could be stimulated by ATP. The ATP-dependent uptake of GSSG had a Km of 43 +/- 3 microM and a Vmax of 900 +/- 200 nmol/mg protein/min. The ATP-dependent uptake of GS-DNP seemed to be non-competitively inhibited by the anthracycline daunorubicin (DNR), whereas the ATP-dependent GSSG uptake seemed to be competitively inhibited by DNR. A substrate binding site on MRP is proposed that comprises a pocket in which both DNR and GS-DNP or GSSG bind in random order to different, only partly overlapping sites. In this pocket binding of a second compound is influenced by the compound which was bound first.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Drug resistance, multiple Biological transport Adenosine triphosphate Kinetics Glutathione/aa Daunorubicin
Megjelenés:	Biochimica et Biophysica Acta (BBA). Biomembranes. - 1326 : 1 (1997), p. 12-22. -
További szerzők:	Hooijberg, Jan H. Scheffer, George L. Szabó Gábor (1953-) (biofizikus) Westerhoff, Hans V. Lankelma, Jan
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001-es BibID:	BIBFORM006039
035-os BibID:	PMID:2317496
Első szerző:	Lakos Zsuzsa (biofizikus)
Cím:	The effect of transmembrane potential on the dynamic behavior of cell membranes / Z. Lakos, B. Somogyi, M. Balazs, J. Matko, S. Damjanovich
Dátum:	1990
ISSN:	0005-2736
Megjegyzések:	The relationship between transmembrane potential and lipid dynamics in the cytoplasmic membrane of mouse thymus cells has been investigated. Changes of transmembrane potential was followed by measuring the fluorescence emission of the anionic dye, bis-(1,3-dibutylbarbiturate)trimethine oxonol (diBa-C4-(3)). Assessment of lipid fluidity was carried out applying three fluorescent lipid probes, 1-[4-(trimethylammonium)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH), 12-(9-anthroyloxy)stearic acid (12-AS) and 1,6-diphenyl-1,3,5-hexatriene (DPH) used to monitor different structural regions of the bilayer. The fluorescence anisotropy of these probes was measured as a function of temperature at two values of transmembrane potential. In the case of DPH it proved to depend on the membrane potential in the higher temperature range (above 28 degrees C), while no such a dependence could be observed for DPH below this temperature range and for TMA-DPH and 12-AS in between 20 and 37 degrees C. These data suggest that changes in transmembrane potential are accompanied with some local alteration in membrane lipid dynamics and/or structure
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Cell membrane potential Membrane fluidity Lipid packing Fluorescence Fluorescence anisotropy
Megjelenés:	Biochimica et Biophysica Acta (BBA). Biomembranes. - 1023 : 1 (1990), p. 41-46. -
További szerzők:	Somogyi Béla (1945-2006) (biofizikus) Balázs Margit (1952-) (sejtbiológus, molekuláris genetikus) Matkó János (1952-) (biológus) Damjanovich Sándor (1936-2017) (biofizikus)
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001-es BibID:	BIBFORM043988
Első szerző:	Szabó Gábor (biofizikus)
Cím:	Light-induced permeabilization and merocyanine 540 staining of mouse spleen cells / Szabo Gábor, Rédai Imre, Bacso Zsolt, Hevessy Jozsef, Damjanovich Sándor
Dátum:	1989
ISSN:	0005-2736
Megjegyzések:	Merocyanine 540 (M540) is a potential-sensitive, hydrophobic dye that preferentially incorporates into the 'fluid' domains of cellular membranes, distinguishing between hemopoietic cells according to their differentiation state. A bright staining with M540 is usually achieved by UV illumination of the cells during staining. We show by flow cytometric analysis that: (1) staining is greatly enhanced by UV illumination of mouse spleen cells before addition of the dye; (2) UV treatment causes an increased permeability toward propidium iodide and intracellular fluorescein as well; (3) the increment in M540 fluorescence precedes permeabilization to propidium iodide, while the latter precedes leakage of fluorescein. We also describe an overshoot and accelerated recovery of M540 fluorescence after photobleaching by a 514 nm laser beam. It is suggested that penetration of M540 to the more fluid inner membrane structures explains the fluorescence increment in both experiments.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Biochimica et Biophysica Acta (BBA). Biomembranes. - 979 : 3 (1989), p. 365-370. -
További szerzők:	Rédai Imre (1961-) (sebész, aneszteziológus) Bacsó Zsolt (1963-) (biofizikus) Hevessy József Damjanovich Sándor (1936-2017) (biofizikus)
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001-es BibID:	BIBFORM006058
Első szerző:	Weidema, Adam Freek (biofizikus)
Cím:	A Ca2+-dependent K+-channel in freshly isolated and cultured chick osteoclasts / Adam F. Weidema, Jan H. Ravesloot, György Panyi, Peter J. Nijweide, Dirk L. Ypey
Dátum:	1993
ISSN:	0005-2736
Megjegyzések:	Calcium-activated potassium channels were found in embryonic chick osteoclasts using the patch-clamp technique. The activity of the channel was increased by both membrane depolarisation and an increase in intracellular Ca2+ concentration in the range 10(-5) to 10(-3) M. In the cell-attached-patch configuration the channel was only active at extreme depolarising potentials. Ca2+ addition to the cytoplasm via ionomycin increased channel activity at the resting membrane potential of the osteoclast. The channel had a single-channel conductance of 150 pS in the inside-out patch under symmetrical K+ conditions (150 mM) and was selective for potassium ions. During sustained application of increased [Ca2+] at the cytoplasmic side of inside-out patches, channel activity sometimes decreased again after the initial increases (desensitization). The results established the properties of the single channels underlying an outward rectifying K+ conductance in chick osteoclasts described previously by us.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Potassium ion channel Calcium ion dependence Patch clamp Depolarization Calcium ion concentration, intracellular Chick osteoclast
Megjelenés:	Biochimica et Biophysica Acta (BBA). Biomembranes. - 1149 : 1 (1993), p. 63-72. -
További szerzők:	Ravesloot, Jan Hindrik (1961-) Panyi György (1966-) (biofizikus) Nijweide, Peter J. Ypey, Dirk L.
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