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001-es BibID:	BIBFORM006025
Első szerző:	Balázs Margit (sejtbiológus, molekuláris genetikus)
Cím:	Fluorescent tetradecanoylphorbol acetate : a novel probe of phorbol ester binding domains / Balázs, M., Szöllösi, J., Lee, W. C., Haugland, R. P., Guzikowski, A. P., Fulwyler, M. J., Damjanovich, S., Feuerstein, B. G., Pershadsingh, H. A.
Dátum:	1991
Megjegyzések:	Protein kinase C (PKC) has a prominent role in signal transduction of many bioactive substances. We synthesized the fluorescent derivative, phorbol-13-acetate-12-N-methyl-N-4-(N,N'-di(2-hydroxyethyl)amino)-7-n itr obenz-2-oxa-1,3-diazole-aminododecanoate (N-C12-Ac(13)) of 12-O-tetradecanoylphorbol-13-acetate (TPA) to monitor the location of phorbol ester binding sites and evaluate its potential use as a probe of PKC in viable cells. The excitation maximum wavelength of N-C12-Ac(13) is close to 488 nm, facilitating its use in argon-ion laser flow and imaging cytometry. When incubated with 100 nM N-C12-Ac(13) at 25 degrees C, P3HR-1 Burkitt lymphoma cells accumulated the dye rapidly, reaching maximum fluorescence within 25 min, 20-fold above autofluorescence. Addition of unlabeled TPA significantly decreased the fluorescence of N-C12-Ac(13) stained cells in a dose-dependent manner indicating specific displacement of the bound fluoroprobe. Competitive displacement of [3H]-phorbol-12,13-dibutyrate ([3H]-PBu2) from rat brain cytosol with N-C12-Ac(13) gave an apparent dissociation constant (Kd) of 11 nM. N-C12-Ac(13) possessed biological activity similar to TPA. Like TPA (final concentration 65 nM) N-C12-Ac(13), at a lower concentration (51 nM), induced expression of Epstein-Barr viral glycoprotein in P3HR-1 cells, differentiation of promyelocytic HL60 cells, and caused predicted changes in the mitotic cycle of histiocytic DD cells. Microspectrofluorometric images of single cells labeled with N-C12-Ac(13) showed bright fluorescence localized intracellularly and dim fluorescence in the nuclear region, consistent with dye binding mainly to cytoplasmic structures and/or organelles and being mostly excluded from the nucleus. Because of the high level of non-specific binding of N-C12-Ac(13), this probe is not ideal for visualizing PKC in intact cells, but would be a valuable fluoroprobe to investigate the kinetic properties of purified PKC. Also, knowledge gained from these studies allows us to predict structures of fluorescent phorbols likely to have less non-specific binding and, consequently, be potentially useful for monitoring PKC in viable cells.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban analysis Animal Antigens,Viral Binding Sites Brain Chemistry Cell Cycle chemical synthesis Cytosol Dyes Female Flow Cytometry Fluorescence Fluorescence Polarization Fluorescent Dyes Gene Expression Herpesvirus 4,Human Image Processing,Computer-Assisted immunology metabolism Oxadiazoles pharmacology Phorbol Esters Protein Kinase C Rats Rats,Inbred Strains Signal Transduction Support,Non-U.S.Gov't Support,U.S.Gov't,P.H.S. Tetradecanoylphorbol Acetate Tumor Cells,Cultured
Megjelenés:	Journal of Cellular Biochemistry. - 46 : 3 (1991), p. 266-276. -
További szerzők:	Szöllősi János (1953-) (biofizikus) Lee, W. C. Haugland, R. P. Guzikowski, A. P. Fulwyler, Mack J. Damjanovich Sándor (1936-2017) (biofizikus) Feuerstein, Burt G. Pershadsingh, Harrihar A.
Internet cím:	elektronikus változat
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001-es BibID:	BIBFORM006049
Első szerző:	Pershadsingh, Harrihar A.
Cím:	Effects of ciglitazone on blood pressure and intracellular calcium metabolism / Pershadsingh, H. A., Szollosi, J., Benson, S., Hyun, W. C., Feuerstein, B. G., Kurtz, T. W.
Dátum:	1993
Megjegyzések:	Ciglitazone is the prototype of the thiazolidinedione class of compounds currently being developed for the treatment of insulin resistance and non-insulin-dependent diabetes. The effects of thiazolidinediones on blood pressure and cell calcium metabolism are not well defined. In the obese Zucker rat, a widely studied model of insulin resistance associated with mild hypertension, we investigated the effects of ciglitazone on plasma insulin levels and mean arterial pressure. We also evaluated the effects of ciglitazone on the changes in cytosolic calcium induced by platelet-derived growth factor in A172 human glioblastoma cells and rat A10 vascular smooth muscle cells. Oral administration of ciglitazone, approximately 45 mg/kg per day for 4 weeks, induced significant reductions in plasma insulin levels (p < 0.001) and blood pressure (p < 0.05). Ciglitazone was also found to significantly attenuate the capacity of platelet-derived growth factor BB homodimer to induce sustained increases in intracellular free calcium. These findings suggest that thiazolidinediones may offer a novel pharmacological approach to the treatment of hypertension, and raise the possibility that these compounds may affect blood pressure not only by affecting insulin metabolism but also by modifying the cell calcium response to pressor agents, growth factors, or both.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Animal blood Blood Pressure Calcium drug effects Female Glioblastoma Human Insulin Intracellular Membranes metabolism Obesity pharmacology Platelet-Derived Growth Factor Rats Rats,Zucker Signal Transduction Thiazoles Tumor Cells,Cultured
Megjelenés:	Hypertension. - 21 : 6 Pt 2 (1993), p. 1020-1023. -
További szerzők:	Szöllősi János (1953-) (biofizikus) Benson, Steve Hyun, William C. Feuerstein, Burt G. Kurtz, Theodore W.
Internet cím:	elektronikus változat
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001-es BibID:	BIBFORM006054
Első szerző:	Szöllősi János (biofizikus)
Cím:	Calcium channels in PDGF-stimulated A172 cells open after intracellular calcium release and are not voltage-dependent / Szollosi, J., Feuerstein, B. G., Vereb, G., Pershadsingh, H. A., Marton, L. J.
Dátum:	1991
Megjegyzések:	Using laser image cytometry and Indo-1 fluorescence, we investigated the intracellular free Ca2+ concentration ([Ca2+]i) of confluent A172 human glioblastoma cells stimulated by the BB homodimer of platelet-derived growth factor (PDGF-BB). The shape of the calcium transients and the delay time between stimulation and the beginning of the transient varied considerably. The percentage of responsive cells, the peak [Ca2+]i and the duration of the response were directly related to PDGF-BB dose, while the delay time was inversely related; the maximal response occurred at a PDGF-BB concentration of 20 ng/ml. Studies with EGTA and inorganic calcium-channel blockers (Ni2+, La3+) showed that the increase of [Ca2+]i resulted from initial release of intracellular stores and subsequent calcium influx across the plasma membrane. Opening of calcium channels in the plasma membrane, monitored directly by studying Mn2+ quenching of Indo-1 fluorescence, was stimulated by PDGF-BB and blocked by La3+; the opening occurred 55 +/- 10 s after the initial increase in [Ca2+]i. Therefore, in these tumor cells, intracellular release always occurs before channel opening in the plasma membrane. Depolarization of cells with high extracellular [K+] did not generally induce calcium transients but did decrease calcium influx. L-type calcium-channel blockers (verapamil, nifedipine, and diltiazem) had little or no effect on the calcium influx induced by PDGF-BB. These results indicate that PDGF-BB induces calcium influx by a mechanism independent of voltage-sensitive calcium channels in A172 human glioblastoma cells.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Calcium Calcium Channel Blockers Calcium Channels Dyes Egtazic Acid Electrophysiology Fluorescence Fluorescent Dyes Glioblastoma Human Image Cytometry Image Processing,Computer-Assisted Indoles Lanthanum metabolism pharmacology Platelet-Derived Growth Factor Signal Transduction Support,Non-U.S.Gov't Support,U.S.Gov't,P.H.S. Tumor Cells,Cultured Verapamil
Megjelenés:	Cell Calcium. - 12 : 7 (1991), p. 477-491. -
További szerzők:	Feuerstein, Burt G. Vereb György (1965-) (biofizikus, orvos) Pershadsingh, Harrihar A. Marton, Laurence J.
Internet cím:	elektronikus változat
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