共查询到20条相似文献,搜索用时 281 毫秒
1.
Plumb RS Johnson KA Rainville P Shockcor JP Williams R Granger JH Wilson ID 《Rapid communications in mass spectrometry : RCM》2006,20(19):2800-2806
Analysis of biological fluids using ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) (metabonomics) can allow new insights to be gained into disease processes, with advances in chromatographic techniques enabling the detection of thousands of metabolites. In this work metabonomics has been used to investigate the metabolic processes involved in type II diabetes in the Zucker obese rat. Plasma was analyzed from three different strains, the Zucker (fa/fa) obese, Zucker lean and the lean/(fa) obese cross. Using UPLC/MS, ca. 10,000 ions were detected due to the narrow peak widths and excellent peak shapes achieved with this technology. Confidence in the chromatographic performance was demonstrated by the use of quality control standards. The positive and negative ion total ion chromatograms obtained from the three strains were readily distinguishable using multivariate statistical analysis. The greatest difference was observed between the Zucker lean and Zucker lean/(fa) rats compared to the Zucker (fa/fa) obese rats. Positive ions m/z 220 (4.36 min), 282(3.78 min), 359 (5.33 min) and 405 (7.77 min) were elevated in the plasma derived from Zucker lean rats whilst ions m/z 385 (6.80 min) and 646 (4.36 min) were at a lower concentration compared to the plasma from the Zucker (fa/fa) obese animals. Negative ions elevated in the Zucker lean rats included m/z 212 (2.30 min), 514 (2.85 min), 295 (4.39 min), 329 (3.11 min), 343 (2.86 min) and 512 (2.86 min) with ions m/z 538 (4.18 min), 568 (4.18 min), 568 (5.09 min) and 612 (4.30 min) being raised in the samples derived from Zucker (fa/fa) obese animals. The ion m/z 514 (3.85 min) was found to correspond to taurocholate, providing further support for an involvement of taurine metabolism in diabetes. 相似文献
2.
As an oral hypoglycemic agent, metformin (Met) has become a best-selling inexpensive drug worldwide. In this thesis, [Cr(metformin)3] (CrMet) complex was synthesized and characterized by elemental analysis (EA), electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (NMR), infrared (IR), UV-visible (UV-vis), and molar conductivity. Meanwhile, the molecule structure of CrMet complex was optimized using Gaussian 09. Considering the therapeutic effect of Met and Met/Cr(III) complex on type 2 diabetes mellitus (T2DM), the biological activities of CrMet in streptozocin (STZ)-induced diabetic mice were evaluated in detail from the aspects of fasting blood glucose (FBG), fasting serum insulin (FINS), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) levels. These results indicated that CrMet had beneficial function on blood glucose (BG) and lipid metabolism for diabetes. Additionally, the results of cytotoxicity and toxicity experiments showed that CrMet had no damage to cells and relatively high safety in mice. It maybe a potential candidate as a therapeutic agent in T2DM. 相似文献
3.
V. V. Yanilkin N. V. Nastapova A. S. Stepanov A. A. Kalinin V. A. Mamedov 《Russian Chemical Bulletin》2009,58(1):89-94
The binding of cations Li+, Na+, K+, Cs+, Ag+, Zn2+, Ni2+, Co2+, NH4
+ (group I), H+, Mg2+, Al3+, Ga3+ (group II), and Ca2+, Pb2+ (group III) by 21,31-diphenyl-l 2,42-dioxo- 7,10,13-trioxa-l,4(3,1)-diquinoxalina-2(2,3),3(3,2)-diindolizinacyclopentadecaphane (1), which contains two indolizine and two quinoxaline fragments and 3,6,9-trioxaundecanes spacer, and by its acyclic analog
(2) was studied using cyclic voltammetry in MeCN/0.1 M Bu4NBF4. It was concluded that the ions of group I are not bound by these compounds, the ions of group II exhibit the reversible
redox-switched binding by the carbamoyl groups of the quinoxaline fragments, whereas the ions of group III are bound not only
by the initial compounds and radical cations 1 and 2, but also by dication 1. This binding of the Ca2+ and Pb2+ ions stabilizes dication 1. 相似文献
4.
Current perspectives of <Superscript>14</Superscript>C-isotope measurement in biomedical accelerator mass spectrometry 总被引:1,自引:0,他引:1
Accelerator mass spectrometry (AMS) is an extremely sensitive nuclear physics technique developed in the mid-70s for radiocarbon dating of historical artefacts. The technique centres round the use of a tandem Van de Graaff accelerator to generate the potential energy to permit separation of elemental isotopes at the single atom level. AMS was first used in the early 90s for the analysis of biological samples containing enriched 14C for toxicology and cancer research. Since that time biomedical AMS has been used in the study of (1) metabolism of xenobiotics in animals and humans (2) pathways of drug metabolism (3) biomarkers (4) metabolism of endogenous molecules including vitamins (5) DNA and protein binding studies and (6) clinical diagnosis. A new drug development concept which relies on the ultrasensitivity of AMS known as human microdosing (Phase 0) is being used to obtain early human metabolism information of candidate drugs arising out of discovery. These various aspects of AMS are reviewed in this article and a perspective on future applications of AMS provided. 相似文献
5.
Metabolome analysis of human cerebrospinal fluid (CSF) is challenging because of low abundance of metabolites present in a
small volume of sample. We describe and apply a sensitive isotope labeling LC-MS technique for qualitative analysis of the
CSF metabolome. After a CSF sample is divided into two aliquots, they are labeled by 13C-dansyl and 12C-dansyl chloride, respectively. The differentially labeled aliquots are then mixed and subjected to LC-MS using Fourier-transform
ion cyclotron resonance mass spectrometry (FTICR MS). Dansylation offers significant improvement in the performance of chromatography
separation and detection sensitivity. Moreover, peaks detected in the mass spectra can be readily analyzed for ion pair recognition
and database search based on accurate mass and/or retention time information. It is shown that about 14,000 features can be
detected in a 25-min LC-FTICR MS run of a dansyl-labeled CSF sample, from which about 500 metabolites can be profiled. Results
from four CSF samples are compared to gauge the detectability of metabolites by this method. About 261 metabolites are commonly
detected in replicate runs of four samples. In total, 1132 unique metabolite ion pairs are detected and 347 pairs (31%) matched
with at least one metabolite in the Human Metabolome Database. We also report a dansylation library of 220 standard compounds
and, using this library, about 85 metabolites can be positively identified. Among them, 21 metabolites have never been reported
to be associated with CSF. These results illustrate that the dansylation LC-FTICR MS method can be used to analyze the CSF
metabolome in a more comprehensive manner. 相似文献
6.
C. J. Sanders J. M. Smoak L. M. Sanders M. N. Waters S. R. Patchineelam M. E. Ketterer 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(3):593-596
A sediment core was taken to determine if sediment accumulation rates could be conducted using 240+239Pu signatures in the coastal mangrove mudflats of southeastern Brazil. The results from this study show that 240+239Pu fallout activities are sufficient and well preserved in the coastal sediments of this region. Sediment accumulation rates
determined from the 240+239Pu signatures were 4.4 mm/year and 4.1 from 210Pb (CIC) method. A sediment mixing coefficient rate was calculated using chlorophyll-a profile (9.5 cm2). 相似文献
7.
V. V. Yanilkin A. S. Stepanov N. V. Nastapova A. R. Mustafina V. A. Burilov S. E. Solov’eva I. S. Antipin A. I. Konovalov 《Russian Journal of Electrochemistry》2010,46(11):1263-1279
The methods of cyclic voltammetry, electrolysis, and spectrophotometry were used to study electrochemical properties of (TCAS
+ Fe3+ + dipy), (CCAS + Fe3+ + dipy), and (CCAS + Fe3+ + [Co(dipy)3]3+) triple systems (where TCAS is n-sulfonatothiacalix[4]arene, CCAS is tetracarboxylate n-sulfonatocalix[4]arene, and dipy = α,α′-dipyridyl) in an aqueous solution. One-electron reduction of Fe(III) in the (TCAS
+ Fe3+ + dipy) system at pH 2.5 results in electroswitching of iron ions from the lower TCAS ring to the upper ([Fe(dipy)3]2+). Reverse electrochemical switching of the system is impossible due to mediator ([Fe(dipy)3]2+/3+) oxidation of TCAS. Reverse electroswitching of Fe(III) ions from unbound to bound state as ([Fe(dipy)3]2+) with CCAS has been revealed in the system (CCAS + Fe3+ + dipy) (pH 1.7) upon single-electron transfer, whereas reversible electroswitching by the upper rim of CCAS from one complex
ion ([Co(dipy)3]3+) to another ([Fe(dipy)3]2+) has been demonstrated in the system ([Co(dipy)3]3+ + CCAS + Fe3+ upon double-electron transfer. In all systems, electric switching was accompanied by synchronous color switching. 相似文献
8.
E. S. Zakaria 《Journal of Radioanalytical and Nuclear Chemistry》2005,264(3):629-635
Summary This paper reports the radiochemical study of the ion-exchange of Cs+, Na+, Sr2+ and Eu3+ ions with H+ by chromium hexacyanoferrate(II) which was prepared in a granular form using a gel method. The slow steps which determine the rate of exchange of these ions are directly proportional to the particle diameter and this is confirmed from the linearity test of Bt vs. t plots at different particle diameters. Boyed’s equation and Reichenberg’s tables were used for evaluating all the kinetic parameters. The results reveal that the effective particle radii are unchanged for both chromium hexacyanoferrate(II) dried at 60 and 120 °C. The obtained data were analyzed using McKay plots and Arrhenius equation and the kinetic and thermodynamic parameters, e.g., effective diffusion coefficient, activation energies and entropies of activation have been evaluated. The mobility of these ions inside the particles of chromium hexacyanoferrate(II) decrease in the order of Eu3+>Sr2+>Na+⊃Cs+. 相似文献
9.
Alm E Slagbrand T Aberg KM Wahlström E Gustafsson I Lindberg J 《Analytical and bioanalytical chemistry》2012,403(2):443-455
In 1H NMR metabolomic datasets, there are often over a thousand peaks per spectrum, many of which change position drastically
between samples. Automatic alignment, annotation, and quantification of all the metabolites of interest in such datasets have
not been feasible. In this work we propose a fully automated annotation and quantification procedure which requires annotation
of metabolites only in a single spectrum. The reference database built from that single spectrum can be used for any number
of 1H NMR datasets with a similar matrix. The procedure is based on the generalized fuzzy Hough transform (GFHT) for alignment
and on Principal-components analysis (PCA) for peak selection and quantification. We show that we can establish quantities
of 21 metabolites in several 1H NMR datasets and that the procedure is extendable to include any number of metabolites that can be identified in a single
spectrum. The procedure speeds up the quantification of previously known metabolites and also returns a table containing the
intensities and locations of all the peaks that were found and aligned but not assigned to a known metabolite. This enables
both biopattern analysis of known metabolites and data mining for new potential biomarkers among the unknowns. 相似文献
10.
Metabolism of <Superscript>14</Superscript>C-labelled and non-labelled sulfadiazine after administration to pigs 总被引:1,自引:0,他引:1
Lamshöft M Sukul P Zühlke S Spiteller M 《Analytical and bioanalytical chemistry》2007,388(8):1733-1745
The behaviour of sulfadiazine (SDZ) and its metabolites was investigated by administering the 14C-labelled veterinary drug to fattening pigs. The excretion kinetics were determined after daily collection of manure. Two
known metabolites, N-acetylsulfadiazine and 4-hydroxysulfadiazine, and two hitherto unidentified minor metabolites were recovered. Various mass
spectrometric techniques such as parent, product ion scans and accurate mass measurement were used. The new compounds were
identified as N-formylsulfadiazine (For-SDZ) and N-acetyl-4-hydroxysulfadiazine (Ac-4-OH-SDZ). The identification of SDZ, Ac-SDZ and For-SDZ was confirmed by comparison of
the spectroscopic and chromatographic data of the synthesized authentic references. The identification of the hydroxylated
compounds 4-OH-SDZ and Ac-4-OH-SDZ was performed by MSn, and accurate mass measurements. Only 4% of the administered radioactivity remained in the pig after ten days and SDZ accounted
for 44% of the 96% radioactivity excreted. More than 93% of the labelled compounds were detected and identified in the manure.
The key analytical problem, namely a high concentration of matrix in sample extracts, was overcome by advanced measurement
techniques and with the use of a suitable internal standard. The mean recoveries for all compounds were ≥96%. Linearity was
established over a concentration range of 0.5 to 10,000 μg kg−1 manure with a correlation coefficient ≥0.99. The same experiment was carried out simultaneously with non-labelled SDZ to
obtain manure for outdoor soil experiments. 相似文献
11.
Non-aggregated spherical polystyrene (PS) particles were coated with GdPO4:Tb3+/Ce3+ phosphor layers by a conventional hydrothermal synthesis using poly(vinylpyrrolidone) (PVP) as an additive without further
annealing treatment. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy
(TEM), photoluminescence (PL), as well as luminescence decay experiments were used to characterise the resulting core-shell
structured PS@GdPO4:Tb3+/Ce3+ samples. The results of XRD indicated that the PS particles were successfully coated with the GdPO4:Tb3+/Ce3+ phosphor layers, which could be further verified by the images of FESEM. Under ultraviolet excitation, the PS@GdPO4:Tb3+/Ce3+ phosphors show Tb3+ characteristic emission, i.e. 5D4-7FJ (J = {6, 5, 4, 3}) emission lines with green emission 5D4-7F5 (543 nm) as the most prominent group. The core-shell phosphors so obtained have potential applications in field emission
display (FED) and plasma display panels (PDP). 相似文献
12.
García-Galán MJ Frömel T Müller J Peschka M Knepper T Díaz-Cruz S Barceló D 《Analytical and bioanalytical chemistry》2012,402(9):2885-2896
This work evaluates the biodegradation of N
4-acetylsulfapyridine (AcSPY) and N
4-acetylsulfamethazine (AcSMZ), metabolites of two of the most commonly used sulfonamides (SAs) in human and veterinary medicine,
respectively. Aerobic transformation in effluent wastewater was simulated using aerated fixed-bed bioreactors. No visible
changes in concentration were observed in the AcSMZ reactor after 90 days, whereas AcSPY was fully degraded after 32 days
of experiment. It was also demonstrated that AcSPY transformed back to its parent compound sulfapyridine (SPY). The environmental
presence of these two metabolites in wastewater effluent had been previously investigated and confirmed, together with three
more SA acetylated metabolites and their corresponding parent compounds, in 18 different wastewater treatment plants in Hesse
(Germany). Sulfamethoxazole (SMX) and SPY were the two SAs detected most frequently (90% and 89% of the samples, respectively)
and in the highest concentrations (682 ng L−1 for SMX and 532 ng L−1 for SPY). To conclude, hazard quotients were calculated whenever toxicity data were available. None of the SAs studied posed
an environmental risk. 相似文献
13.
Yufen Chen Tengxuan Tang Yuhua Chen Dongmei Xu 《Research on Chemical Intermediates》2018,44(4):2379-2393
A novel 1,8-naphthalimide dye with simple structure has been produced by a facile synthetic method for colorimetric and fluorescent sensing of H+ and Cu2+. In CH3CN/H2O (1/1, v/v), the dye could monitor H+ using dual channels (ratiometric absorbance and fluorescence intensity change) from pH 6.2 to 12.0. Meanwhile, in the pH range of 1.9–5.2, the dye could also be used to detect Cu2+ using triple channels [ultraviolet–visible (UV–Vis) absorption, fluorescence intensity reduction, as well as fluorescence blueshift]. The detection limits for Cu2+ evaluated by colorimetric and fluorescent titration were 6.10 × 10?7 and 2.62 × 10?7 M, respectively. The dye exhibited specific selectivity and sensitivity for H+ and Cu2+ over various coexisting metal ions. Moreover, the sensing mechanism of the dye for H+ and Cu2+ was carefully examined. 相似文献
14.
K. Norisuye K. Okamura Y. Sohrin H. Hasegawa T. Nakanishi 《Journal of Radioanalytical and Nuclear Chemistry》2005,267(1):183-193
Summary The present paper describes a new analytical method for determining the 240Pu/239Pu isotopic ratio and 238Pu/239+240Pu α -activity ratio in seawater, both of which are important parameters for determining Pu sources in the ocean. Plutonium
isotopes were preconcentrated from a large volume of seawater (4700-10800 liter) by solid phase extraction using MnO2-impregnated fibers and eluted into 3M HCl. After the elution, the Pu species of all oxidation states were converted to Pu(IV)
using NaNO2, purified by solvent extraction using thenoyltrifluoroacetone (TTA)-benzene, and concentrated in 5 ml of 0.2M HNO2. The 240Pu/239Pu and 238Pu/239+240Pu ratios in the 5-ml final solution were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and α-spectrometry,
respectively. A pg level of Pu, which was a sufficiently large amount for the determination, was obtained by the solid phase
extraction. Through the redox conversion and solvent extraction, the Pu species, such as Pu(III), Pu(IV) and Pu(VI), were
collected at a high recovery of 96±2% (n=3) despite the presence of large amounts of Mn, and interfering 238U (3.3 μg. l-1in seawater) was effectively removed with a decontamination factor of 1.7·107. The accuracy of the method for the 240Pu/239Pu ratio was verified using reference materials of seawater and a terrestrial soil sample. The present technique was applied
to the determination of the 240Pu/239Pu and 238Pu/239+240Pu ratios in coastal and oceanic water. 相似文献
15.
Saeedeh Hashemian 《Russian Journal of Inorganic Chemistry》2011,56(3):397-401
The imidazol side group of histidine has two nitrogen atoms capable of being protonated or participating in metal binding.
Hence, histidine can take on various metal-bound and protonated forms in proteins. Because of its variable structural state,
histidine often functions as a key amino acid residue in enzymatic reactions. Ab initio (HF and MP2) calculations were done
in modeling the cation (H+, Li+, Na+, K+, Mg2+, Ca2+) interaction with side chain of histidine. The region selectivity of metal ion complexation is controlled by the affinity
of the side of attack. In the imidazol unite of histidine the ring nitrogen has much higher metal ion (as well as proton)
affinity. The complexation energies with the model systems decrease in the following order: Mg2+ > Ca2+ > Li+ > Na+ > K+. The variation of the bond lengths and the extent of charge transfer upon complexation correlate well with the computed interaction
energies. 相似文献
16.
The reduction of immobile cations La3+ and Ce3+ in fluoride-conducting solid electrolytes (FSE) LaF3 (Eu2+ 0.8 mol %), LaF3 (Sr2+ 5 mol %), and CeF3 (Sr2+ 5 mol %) in contact with Ag, Bi, Si, La, Ce, and Sm working electrodes is studied by chronoamperometry and voltammetry with linear potential scan. Discovered is linear dependence of initial segments of potentiostatic transients of cathodic current on t
1/2 at FSE interfaces with Ag, Bi, La, Ce, and Sm. The dependence is due to diffusion-controlled instantaneous nucleation of Ln and Ce. The La3+ and Ce3+ reduction at the FSE/Ag interface is reversible in a narrow region. The reduction and oxidation of La3+ and Ce3+ (cations of the FSE rigid lattice) at the FSE/Me (Me = La, Ce and Sm, Bi, Si) interface is irreversible and involves a chemical reaction.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 662–672.Original Russian Text Copyright © 2005 by Turaeva, Kot, Urchukova, Murin. 相似文献
17.
Maryam Ebrahimi Jahan Bakhsh Raoof Reza Ojani 《Journal of the Iranian Chemical Society》2018,15(8):1871-1880
In the present paper, we used single-stranded poly-T (100% thymine bases) and poly-C (100% cytosine bases) nucleic acids as DNA probes for selective and sensitive individual electrochemical determination of Hg2+ and Ag+, respectively, on the multi-walled carbon nanotube paste electrodes (MWCNTPEs) using [Fe(CN)6]3?/4? as electroactive labels. In the presence of Hg2+ and Ag+, the probe–Hg2+/Ag+ interactions through T–Hg2+–T and C–Ag+–C complexes formation could cause the formation of a unimolecular hybridized probe. This structure of probe led to its partial depletion from electrode surface and facilitation of electron transfer between [Fe(CN)6]3?/4? redox couple and electrode surface, resulting in the enhanced differential pulse voltammetry (DPV) oxidation current of [Fe(CN)6]3?/4? at the probe-modified electrode surface. We applied the difference in the oxidation peak currents of [Fe(CN)6]3?/4? before and after Hg2+/Ag+–DNA probe bonding (?I) for electrochemical determination of these heavy metal ions. Detection limits were 8.0?×?10?12 M and 1.0?×?10?11 M for Hg2+ and Ag+ ions determination, respectively. The biosensors were utilized to determine the weight percent of toxic metals, i.e., silver and mercury in dental amalgam filling composition. The results of their practical applicability in analysis of the amalgam sample were satisfactory. 相似文献
18.
Karin Popa Alexandru Cecal Doina Humelnicu Ioan Caraus Camelia L. Draghici 《Central European Journal of Chemistry》2004,2(3):434-445
This study concerns the removal of the 137Cs+ and 60Co2+ β+γ-radioactive ions in Azolla caroliniana Willd. water fern. The living fern and two different types of biosorbent prepared from Azolla caroliniana were tested to remove the above-mentioned radioactive ions from dilute solutions, in the absence and in the presence of the
ionic competition. Effective 137Cs+ and 60Co2+ ions removal from low radioactive wastewaters was demonstrated. The time dependent K
d
(t) values were calculated from the absorption data. These results indicate that removal process achieved equilibrium in about
120 min and that it involves two steps: rapid and slow absorption; the active process (metabolic bioaccumulation on the living
fern) was responsible for above one half of the total removal process. A thin layer radiochromatography study leads to the
conclusion that the biochemical components in which 137Cs+ and 60Co2+ place themselves are of a polysaccharide and lipoid fractions. 相似文献
19.
K. Dagdeviren P. Ünak R. Bekis F. Z. Biber S. Akdurak O. Ulker B. Ergur T. Ertay H. Durak 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(3):635-639
Magnetically targeted drug delivery by particulate carriers is an efficient method of delivering drugs to localized disease
sites, such as tumors. Thus, high concentrations of carrier molecules such as therapeutic radiopharmaceuticals can be achieved
near the target site without any toxic effects to normal surrounding tissue. In this study, magnetic targeting carriers (MTC)
were radioiodinated with 131I using three different methods (1) 131I was directly bound onto MTC, (2) an iron complex of 8-hydroxyquinoline (8-OHQ) has been absorbed onto magnetic microspheres.
The iodogen method was performed for the iodination of the complexes. (3) 8-OHQ was radioiodinated before chelating with Fe.
Reaction parameters were investigated in order to optimize the final properties of the labeled MTC. The best labeling yield
and the best stability were obtained when 8-OHQ was chelated before the radioiodination. Binding efficiency was found to be
99.58%. The labeling of the MTC with 131I was undertaken to allow for therapy with 131I-labeled MTC with simultaneous imaging. 相似文献
20.
We have investigated the presence of foreign ions into the bulk structure and the external surfaces of aragonite using periodic
ab-initio methods. Four cations isovalent to Ca2+ were studied: Mg2+, Sr2+, Ba2+ and Zn2+. The calculations were performed at structures (bulk, surface) that contain four and eight CaCO3 units. Our results, at the Hartree-Fock level, show that the incorporation of those ions into aragonite depends strongly
on their size. Mg2+ and Zn2+, due to their smaller size, can substitute Ca2+ ions in the crystal lattice while the incorporation of Sr2+ and Ba2+ into aragonite is energetically less favoured. Examination of the [011], [110] and [001] surfaces of aragonite revealed that
the surface incorporation reduces the energetic cost for the larger ions. These systems provide challenging examples for most
shape analysis methods applied in Mathematical Chemistry. 相似文献