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001-es BibID:	BIBFORM047924
Első szerző:	Brücher Ernő (vegyész)
Cím:	Stability and Toxicity of Contrast Agents / Ernő Brücher, Tircsó Gyula, Zsolt Baranyai Zoltán Kovács, A. Dean Sherry
Dátum:	2013
ISBN:	978-1-119-99176-2
Tárgyszavak:	Természettudományok Kémiai tudományok könyvfejezet Molekulatudomány
Megjelenés:	The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging / ed. André Merbach, Lothar Helm, Éva Tóth. - p. 157-208. -
További szerzők:	Tircsó Gyula (1977-) (vegyész, kémia tanár) Baranyai Zsolt (1977-) (vegyész) Kovács Zoltán (1963-) (vegyész, angol szakfordító) Sherry, A. Dean
Pályázati támogatás:	K-84291 OTKA TÁMOP-4.2.2/B-10/1-2010-0024 TÁMOP TÁMOP-4.2.1/B-09/1/KONV-2010-0007 TÁMOP Bimodális kontrasztanyagok tervezése, előállítása és komplexeik fizikai-kémiai tulajdonságaik jellemzése
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001-es BibID:	BIBFORM006198
Első szerző:	Kálmán Ferenc K. (vegyész)
Cím:	Synthesis, potentiometric, kinetic, and NMR studies of 1,4,7,10-tetraazacyclododecane-1,7-bis(acetic acid)-4,10-bis(methylenephosphonic acid) (DO2A2P) and its complexes with Ca(II), Cu(II), Zn(II) and lanthanide(III) ions / Kalman, F. K., Baranyai, Z., Toth, I., Banyai, I., Kiraly, R., Brucher, E., Aime, S., Sun, X., Sherry, A. D., Kovacs, Z.
Dátum:	2008
ISSN:	0020-1669
Megjegyzések:	A cyclen-based ligand containing trans-acetate and trans-methylenephosphonate pendant groups, H(6)DO2A2P, was synthesized and its protonation constants (12.6, 11.43, 5.95, 6.15, 2.88, and 2.77) were determined by pH-potentiometry and H-1 NMR spectroscopy. The first two protonations were shown to occur at the two macrocyclic ring N-CH2-PO32- nitrogens while the third and fourth protonations occur at the two phosphonate groups. In parallel with protonation of the two -PO32- groups, the protons from the NH+-CH2-PO32- are transferred to the N-CH2-COO- nitrogens. The stability constants of the Ca2+, Cu2+, and Zn2+ (ML, MHL, MH2L, and M2L) complexes were determined by direct pH-potentiometry. Lanthanide(III) ions (Ln(3+)) form similar species, but the formation of complexes is slow; so, "out-of-cell" pH-potentiometry (La3+, Eu3+, Gd3+, Y3+) and competitive spectrophotometry with Cu(II) ion (Lu3+) were used to determine the stability constants. By comparing the log K-ML values with those of the corresponding DOTA (H(4)DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and DOTP (H8DOTP = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylenephosphonic acid) complexes, the order DOTA < DO2A2P < DOTP was found for all the metal ion complexes examined here with the exception of the Ca2+ complexes, for which the order is reversed. The relaxivity of Gd(DO2A2P) decreases between pH 2 and 7 but remains constant in the pH range of 7 < pH < 12 (r(1) = 3.6 mM(-1) s(-1)). The linewiths of the O-17 NMR signals of water in the absence and presence of Gd(DO2A2P) (at pH = 3.45 and 8.5) between 274 and 350 K are practically the same, characteristic of a q = 0 complex. Detailed kinetic studies of the Ce3+ and Gd3+ complexes with DO2A2P showed that complex formation is slow and involves a high stability diprotonated intermediate Ln(H(2)DO2A2P). Rearrangement of the diprotonated intermediate into the final complex is an OH- assisted process but, unlike formation of Ln(DOTA) complexes, rearrangement of Ln(H(2)DO2A2P) also takes place spontaneously likely as a result of transfer of one of the protons from a ring nitrogen to a phosphonate group. The order of the OH- assisted formation rates of complexes is DOTA > DO2A2P > DOTP while the order of the proton assisted dissociation rates of the Gd3+ complexes is reversed, DOTP > DO2A2P > DOTA. H-1 and C-13 NMR spectra of Eu(DO2A2P) and Lu(DO2A2P) were assigned using two-dimensional correlation spectroscopy (2D COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear chemical shift correlation (HETCOR), and exchange spectroscopy (EXSY) NMR methods. Two sets of H-1 NMR signals were observed for Eu(DO2A2P) characteristic of the presence of two coordination isomers in solution, a twisted square antiprism (TSAP) and a square antiprism (SAP), in the ratio of 93% and 7%, respectively. Line shape analysis of the H-1 NMR spectra of Lu(DO2A2P) gave lower activation parameters compared to La(DOTP) for interconversion between coordination isomers. This indicates that the Ln(DO2A2P) complexes are less rigid probably due to the different size and spatial requireents of the carboxylate and phosphonate groups.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Inorganic Chemistry. - 47 : 9 (2008), p. 3851-3862. -
További szerzők:	Baranyai Zsolt (1977-) (vegyész) Tóth Imre (1950-) (vegyész) Bányai István (1953-) (vegyész) Király Róbert Brücher Ernő (1935-) (vegyész) Aime, Silvio Sun, Xiankai Sherry, A. Dean Kovács Zoltán
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001-es BibID:	BIBFORM038094
Első szerző:	Rojas-Quijano, Federico A.
Cím:	Synthesis and Characterization of a Hypoxia-Sensitive MRI Probe / Federico A. Rojas-Quijano, Gyula Tircsó, Enikő Tircsóné Benyó, Zsolt Baranyai, Huan Tran Hoang, Ferenc K. Kálmán, Praveen K. Gulaka, Vikram D. Kodibagkar, Silvio Aime, Zoltán Kovács, A. Dean Sherry
Dátum:	2012
ISSN:	0947-6539
Megjegyzések:	Tissue hypoxia occurs in pathologic conditions, such as cancer, ischemic heart disease and stroke when oxygen demand is greater than oxygen supply. An imaging method that can differentiate hypoxic versus normoxic tissue could have an immediate impact on therapy choices. In this work, the gadolinium complex of 1,4,7,10-tetraaza-1,4,7,10-tetraacetate (DOTA) with a 2-nitroimidazole attached to one carboxyl group via an amide linkage was prepared, characterized and tested as a hypoxia-sensitive MRI agent. A control complex, Gd(DO3A-monobutylamide), was also prepared in order to test whether the nitroimidazole sidechain alters either the water proton T1 relaxivity or the thermodynamic stability of the complex. The stabilities of these complexes were lower than thatof Gd(DOTA)- as expected for monoamide derivatives. The water proton T1 relaxivity (r1), bound water residence lifetime (tM) and rotational correlation time (tR) of both complexes was determined by relaxivity measurements, variable temperature 17O NMR spectroscopy and proton nuclear magnetic relaxation dispersion (NMRD) studies. The resulting parameters (r1=6.38 mM-1 s-1 at 20 MHz, tM=0.71 ms, tR=141 ps) determined for the nitroimidazole derivative closely parallel those of other Gd(DO3A-monoamide) complexes of similar molecular size. In vitro MR imaging experiments with 9L rat glioma cells maintained under nitrogen (hypoxic) versus oxygen (normoxic) gas showed that both agents enter cells but only the nitroimidazole derivative was trapped in cells maintained under N2 as evidenced by an approximately twofold decrease in T1 measured for hypoxic cells versus normoxic cells exposed to this agent. These results suggest that the nitroimidazole derivative might serve as a molecular reporter for discriminating hypoxic versus normoxic tissues by MRI.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Molekulatudomány
Megjelenés:	Chemistry-A European Journal. - 18 : 31 (2012), p. 9669-9676. -
További szerzők:	Tircsó Gyula (1977-) (vegyész, kémia tanár) Tircsóné Benyó Enikő (1977-) (vegyész, kémia tanár) Baranyai Zsolt (1977-) (vegyész) Tran-Hoang, Huan Kálmán Ferenc K. (1978-) (vegyész) Gulaka, Praveen K. Kodibagkar, Vikram D. Aime, Silvio Kovács Zoltán (1963-) (vegyész, angol szakfordító) Sherry, A. Dean
Pályázati támogatás:	TÁMOP-4.2.1/B-09/1/KONV-2010-0007 TÁMOP Bimodális kontrasztanyagok tervezése, előállítása és komplexeik fizikai-kémiai tulajdonságaik jellemzése TÁMOP-4.2.2./B-10/1-2010-0024 TÁMOP K84291 OTKA PD83253 OTKA
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001-es BibID:	BIBFORM010537
Első szerző:	Rojas-Quijano, Federico A.
Cím:	Lanthanide(III) Complexes of Tris(amide) PCTA Derivatives as Potential Bimodal Magnetic Resonance and Optical Imaging Agents / Federico A. Rojas-Quijano, Enikő Tircsóné Benyó, Gyula Tircsó, Ferenc K. Kálmán, Zsolt Baranyai, Silvio Aime, A. Dean Sherry, Zoltán Kovács
Dátum:	2009
ISSN:	0947-6539
Megjegyzések:	Lanthanide complexes of two tris(amide) derivatives of PCTA were synthesized and characterized. The relaxometric and luminescence properties of their lanthanide complexes were investigated as bimodal magnetic resonance (MR) and optical imaging agents. Luminescence studies show that one of the Tb-III complexes dimerizes in solution at low millimolar concentrations, whereas the other may have a higher than expected coordination number in solution. The corresponding Gd-III complexes display unusually high T-1 relaxivities and enhanced kinetic inertness compared to GdPCTA. These features suggest that these new chelates may be suitable for in vivo applications. The fast water-exchange rates observed for these complexes make them unsuitable as paramagnetic chemical exchange saturation transfer (PAR-ACEST) agents.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Chemistry-a European Journal. - 15 : 47 (2009), p. 13188-13200. -
További szerzők:	Tircsóné Benyó Enikő (1977-) (vegyész, kémia tanár) Tircsó Gyula (1977-) (vegyész, kémia tanár) Kálmán Ferenc K. (1978-) (vegyész) Baranyai Zsolt (1977-) (vegyész) Aime, Silvio Sherry, A. Dean Kovács Zoltán
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