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Ginette Ratovo Jean‐Pierre Souchard Pascale Urizzi Yvon Coulais Franoise Nepveu Etienne Hollande 《应用有机金属化学》2004,18(1):1-8
Pancreatic cancer has an extremely poor prognosis, due, in part, to lack of methods for early diagnosis. The present study was designed to evaluate the potential of labeling low‐density lipoprotein (LDL) with a radionuclide using a lipid chelating agent, bis(stearylamide) of diethylenetriaminepentaacetic acid (L), to detect pancreatic tumors by gamma‐scintigraphy. Previous studies indicated that the difficulty of visualization of pancreatic tumors was due to their poor vascularization. This study compares the ability of two radiotracers, 111In–L–LDL and 153Gd–L–LDL to target highly vascularized rat pancreatic tumors (AR4‐2J) implanted in nude mice. Biodistribution studies showed that the tumor uptake of 111In–L–LDL and 153Gd–L–LDL tracers was twofold and fivefold higher respectively than with the controls (111In citrate and 153Gd citrate respectively). These tracers would thus be suitable for scintigraphic imaging. We show here that LDL could be employed as a delivery system for tracers such as 111In or 153Gd when these two radionuclides are complexed by a lipid‐chelating anchor, and that 111In–L–LDL and 153Gd–L–LDL enabled better visualization of the pancreatic tumor tissues, with a better result with 153Gd–L–LDL. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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The previously reported (J. Mol. Spectrosc.68, 195–222 (1977)) study of the CH3D spectrum occurring at 1033–1270 cm?1 which was mainly concerned with the ν6 fundamental has now been extended to cover the region 1270–1420 cm?1. In all, 342 transitions belonging to the ν3 band are now assigned. Both the ν3 and ν6 bands are processed simultaneously taking into account of the Coriolis interaction between them, and the fitting of all the experimental data led to 21 significant spectroscopic constants for the states v6= 1 and v3 = 1 of CH3D. 相似文献
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Cox N Rapatskiy L Su JH Pantazis DA Sugiura M Kulik L Dorlet P Rutherford AW Neese F Boussac A Lubitz W Messinger J 《Journal of the American Chemical Society》2011,133(10):3635-3648
The electronic structures of the native Mn(4)O(x)Ca cluster and the biosynthetically substituted Mn(4)O(x)Sr cluster of the oxygen evolving complex (OEC) of photosystem II (PSII) core complexes isolated from Thermosynechococcus elongatus, poised in the S(2) state, were studied by X- and Q-band CW-EPR and by pulsed Q-band (55)Mn-ENDOR spectroscopy. Both wild type and tyrosine D less mutants grown photoautotrophically in either CaCl(2) or SrCl(2) containing media were measured. The obtained CW-EPR spectra of the S(2) state displayed the characteristic, clearly noticeable differences in the hyperfine pattern of the multiline EPR signal [Boussac et al. J. Biol. Chem.2004, 279, 22809-22819]. In sharp contrast, the manganese ((55)Mn) ENDOR spectra of the Ca and Sr forms of the OEC were remarkably similar. Multifrequency simulations of the X- and Q-band CW-EPR and (55)Mn-pulsed ENDOR spectra using the Spin Hamiltonian formalism were performed to investigate this surprising result. It is shown that (i) all four manganese ions contribute to the (55)Mn-ENDOR spectra; (ii) only small changes are seen in the fitted isotropic hyperfine values for the Ca(2+) and Sr(2+) containing OEC, suggesting that there is no change in the overall spin distribution (electronic coupling scheme) upon Ca(2+)/Sr(2+) substitution; (iii) the changes in the CW-EPR hyperfine pattern can be explained by a small decrease in the anisotropy of at least two hyperfine tensors. It is proposed that modifications at the Ca(2+) site may modulate the fine structure tensor of the Mn(III) ion. DFT calculations support the above conclusions. Our data analysis also provides strong support for the notion that in the S(2) state the coordination of the Mn(III) ion is square-pyramidal (5-coordinate) or octahedral (6-coordinate) with tetragonal elongation. In addition, it is shown that only one of the currently published OEC models, the Siegbahn structure [Siegbahn, P. E. M. Acc. Chem. Res.2009, 42, 1871-1880, Pantazis, D. A. et al. Phys. Chem. Chem. Phys.2009, 11, 6788-6798], is consistent with all data presented here. These results provide important information for the structure of the OEC and the water-splitting mechanism. In particular, the 5-coordinate Mn(III) is a potential site for substrate 'water' (H(2)O, OH(-)) binding. Its location within the cuboidal structural unit, as opposed to the external 'dangler' position, may have important consequences for the mechanism of O-O bond formation. 相似文献
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Ginette Gauyacq 《Discrete Applied Mathematics》1997,80(2-3):149-160
We present a technique for building, in some Cayley graphs, a routing for which the load of every edge is almost the same. This technique enables us to find the edge-forwarding index of star graphs and complete-transposition graphs. 相似文献
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Rapid postcolumn methodology for determination of paralytic shellfish toxins in shellfish tissue 总被引:1,自引:0,他引:1
Rourke WA Murphy CJ Pitcher G van de Riet JM Burns BG Thomas KM Quilliam MA 《Journal of AOAC International》2008,91(3):589-597
A rapid liquid chromatographic (LC) method with postcolumn oxidation and fluorescence detection (excitation 330 nm, emission 390 nm) for the determination of paralytic shellfish toxins (PSTs) in shellfish tissue has been developed. Extracts prepared for mouse bioassay (MBA) were treated with trichloroacetic acid to precipitate protein, centrifuged, and pH-adjusted for LC analysis. Saxitoxin (STX), neoSTX (NEO), decarbamoylSTX (dcSTX), and the gonyautoxins, GTX1, GTX2, GTX3, GTX4, GTX5, dcGTX2, and dcGTX3, were separated on a polar-linked alkyl reversed-phase column using a step gradient elution; the N-sulfocarbamoyl GTXs, C1, C2, C3, and C4, were determined on a C-8 reversed-phase column in the isocratic mode. Relative toxicities were used to determine STX-dihydrochloride salt (diHCl) equivalents (STXeq). Calibration graphs were linear for all toxins studied with STX showing a correlation coefficient of 0.999 and linearity between 0.18 and 5.9 ng STX-diHCI injected (equivalent to 3.9-128 microg STXeq/100 g in tissue). Detection limits for individual toxins ranged from 0.07 microg STXeq/100 g for C1 and C3 to 4.1 microg STXeq/100 g for GTX1. Spike recoveries ranged from 76 to 112% in mussel tissue. The relative standard deviation (RSD) of repeated injections of GTX and STX working standard solutions was < 4%. Uncertainty of measurement at a level of 195 microg STXeq/100 g was 9%, and within-laboratory reproducibility expressed as RSD was 4.6% using the same material. Repeatability of a 65 microg STXeq/100 g sample was 3.0% RSD. Seventy-three samples were analyzed by the new postcolumn method and both AOAC Official Methods for PST determination: the MBA (y = 1.22x + 13.99, r2 = 0.86) and the precolumn LC oxidation method of Lawrence (y = 2.06x + 12.21, r2 = 0.82). 相似文献
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Abstract— The absorption, fluorescence and phosphorescence spectra along with the phosphorescence decay function of indole perturbed by various amounts of halocarbons have been studied in a 1:1 ethanol-ether glass at 77 K. For carbon tetrachloride. chloroform, halothane and methylene chloride used as quenchers. the biexponential nature of the phosphorescence decay prompted us to assume the existence of a triplet state complex (exciplex) between indole and the halocarbons. On the other hand. propyl bromide gives rise to a non-exponential decay and to an increase in the phosphorescence intensity suggesting the occurrence of a normal external spin-orbital coupling interaction between indole and the propyl bromide molecule. 相似文献
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Olivier Horner Pascaline Herbelin Sébastien Goudot Alain Boussac Pierre Bonville 《Hyperfine Interactions》2010,196(1-3):369-375
In this work, the nature of the deposit found inside an industrial cooling circuit (which consists of a mixture of different iron containing phases) has been characterized in detail by 57Fe Mössbauer spectroscopy. Electron Paramagnetic Resonance spectroscopy was also used to check for the presence of other metals, mainly manganese and copper, detected by the Inductive Coupled Plasma method. We conclude that the deposit contains a large amount of Fe(III), probably consisiting of ferrihydrite nanoparticles and of goethite, either bulk or as large particles. It also contains traces of an Fe(II) species (about 3%), probably adsorbed on the iron oxides. Mn(II) and traces of Cu(II) are also present. 相似文献