M Milagros Gómez-Gómez

Complutense University of Madrid, Madrid, Madrid, Spain

Are you M Milagros Gómez-Gómez?

Claim your profile

Publications (21)71.1 Total impact

  • G Artiaga, K Ramos, L Ramos, C Cámara, M Gómez-Gómez
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, silver migration from commercial food containers was evaluated according to European Regulation 10/2011. Several experimental parameters affected silver release: food simulant, temperature, exposition time and sampled bag area. Results demonstrated a significant silver nanoparticle (AgNP) migration into aqueous and acidic simulants. The amount of silver migrated increased with storage time and temperature although, in general, silver showed a low tendency to migrate into food simulants (17ng/g). However, the food simulant did not seem to be a really outstanding variable for long term storage. AF(4)-ICP MS was used to confirm the presence of AgNPs in the simulants. The low limit of detection achieved (0.4μgL(-1)) allowed the identification of AgNPs and their size characterisation (40-60nm). Finally, scanning electron microscopy/energy-dispersive X-ray analysis suggested a possible transformation of the AgNPs detected in the extracts, due to association with other ligands, such as chlorine and sulphur, present in the original containers.
    Food chemistry. 01/2015; 166C:76-85.
  • Source
    I Moraleja, E Moreno-Gordaliza, M L Mena, M M Gómez-Gómez
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, a methodology based on a reducing IEF separation in combination with a FASP tryptic digestion able to maintain the integrity of cisplatin-protein complexes has been developed. The method is based on OFFGEL-IEF under conditions provided by the thiol-free reducing agent TBP, which allowed the separation of cisplatin-binding proteins in liquid fractions. The FASP procedure is applied as an intermediate stage between the IEF separation and MS analysis where the proteins are retained and concentrated in a commercially available ultrafiltration device. The filter unit acts as a proteomic reactor for detergent removal, buffer exchange, chemical modification (reduction and alkylation) and protein digestion. Finally, purified peptides are recovered by centrifugation. This procedure provides efficiencies comparable to standard in-solution digestion and the risk of platinum-complexes loss is minimized due to the fact that reagents employed along the process are subsequently eliminated before the following step. The stability of platinum-protein complexes under the FASP tryptic digestion, either using TBP or DTT as reducing agents, was maintained, allowing the identification of several platinum-containing peptides from cisplatin-HSA. This methodology was applied to the separation of platinum-enriched protein fractions obtained by SEC-ICP-MS in a kidney tissue extract from a rat treated with cisplatin, followed by further identification by nLC-ESI-LTQ-MS/MS after FASP tryptic digestion of selected platinum-containing liquid fractions.
    Talanta 03/2014; 120:433-42. · 3.50 Impact Factor
  • Source
    I. Moraleja, E. Moreno-Gordaliza, M.L. Mena, M.M. Gómez-Gómez
    MethodsX. 01/2014;
  • M L Mena, E Moreno-Gordaliza, M M Gómez-Gómez
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, the reactivity of the citostatic drugs such as oxaliplatin, cisplatin and carboplatin towards proteins and the stability of Pt-protein complexes along their storage were evaluated. Neither native-PAGE nor nrSDS-PAGE seems to be suitable for the separation of carboplatin-binding proteins. A reducing electrophoretic separation procedure able to maintain the integrity of oxaliplatin-protein complexes has been developed. The method is based on SDS-PAGE under conditions provided by the thiol-free reducing agent tris (2-carboxyethyl) phosphine (TCEP), which allowed the separation of oxaliplatin-binding proteins in narrow bands with almost quantitative recoveries. Different amounts of platinum-bound protein bands covering the range 0.3-2.0μg were excised and mineralised for platinum determination, showing good linearity. Limits of detection for a mixture of five standard proteins (transferrin, albumin, carbonic anhydrase, myoglobin and cytochrome c) incubated with oxaliplatin were within the range 11.0-44.0pg of platinum, which were satisfactory for their application to biological samples. The suitability of the TCEP-based SDS-PAGE for the separation of platinum-enriched protein fractions of a kidney cytosol from a rat treated with oxaliplatin was demonstrated. The identification of high Pt to protein ratio cytosolic fractions was carried out by separating the cytosolic platinum-binding proteins by SEC-ICP-MS. Several cytosolic renal proteins were identified in those gel bands containing platinum-enriched protein fractions using nLC-ESI-LTQ-MS/MS after in-gel digested with trypsin. In addition, fractions containing platinum-enriched proteins with lower theorical molecular weight were directly analysed by nLC-ESI-LTQ-MS/MS after in-solution tryptic digestion allowing protein identification.
    Talanta 11/2013; 116:581-92. · 3.50 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: While the anti-tumor efficacy of 2-deoxy-d-glucose (2-DG) is normally low in monotherapy, it may represent a valuable radio- and chemo-sensitizing agent. We here demonstrate that 2-10mM 2-DG cooperates with arsenic trioxide (ATO) and other antitumor drugs to induce apoptosis in human myeloid leukemia cell lines. Using ATO and HL60 as drug and cell models, respectively, we observed that 2-DG/ATO combination activates the mitochondrial apoptotic pathway, as indicated by Bid-, and Bax-regulated cytochrome c and Omi/HtrA2 release, XIAP down-regulation, and caspase-9/-3 pathway activation. 2-DG neither causes oxidative stress nor increases ATO uptake, but causes inner mitochondria membrane permeabilization as well as moderate ATP depletion, which nevertheless do not satisfactorily explain the pro-apoptotic response. Surprisingly 2-DG causes cell line-specific decrease in LKB-1/AMPK phosphorylation/activation, and also causes Akt/mTOR/p70S6K and MEK/ERK activation, which is prevented by co-treatment with ATO. The use of kinase-specific pharmacologic inhibitors and/or siRNAs reveals that apoptosis is facilitated by AMPK inactivation and restrained by Akt and ERK activation, and that Akt and ERK activation mediates AMPK inhibition. Finally, 2-DG stimulates IGF-1R phosphorylation/activation, and co-treatment with IGF-1R inhibitor prevents 2-DG effects on Akt, ERK and AMPK, and facilitates 2-DG-provoked apoptosis. In summary 2-DG elicits IGF-1R-mediated AMPK inactivation and Akt and ERK activation, which facilitates or restrain apoptosis, respectively. 2-DG-provoked AMPK inactivation increases the apoptotic efficacy of ATO, while in turn ATO-provoked Akt and ERK inactivation may increase the efficacy of 2-DG as anti-tumor drug.
    Biochemical pharmacology 10/2012; · 4.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cisplatin is an anticancer agent marred by nephrotoxicity; however, limiting this adverse effect may allow the use of higher doses to improve its efficacy. Cilastatin, a small molecule inhibitor of renal dehydropeptidase I, prevents proximal tubular cells from undergoing cisplatin-induced apoptosis in vitro. Here, we explored the in vivo relevance of these findings and the specificity of protection for kidney cells in cisplatin-treated rats. Cisplatin increased serum blood urea nitrogen and creatinine levels, and the fractional excretion of sodium. Cisplatin decreased the glomerular filtration rate, promoted histological renal injury and the expression of many pro-apoptotic proteins in the renal cortex, increased the Bax/Bcl2 ratio, and oxidative stress in kidney tissue and urine. All these features were decreased by cilastatin, which preserved renal function but did not modify the pharmacokinetics of cisplatin area under the curve. The cisplatin-induced death of cervical, colon, breast, and bladder-derived cancer cell lines was not prevented by cilastatin. Thus, cilastatin has the potential to prevent cisplatin nephrotoxicity without compromising its anticancer efficacy.Kidney International advance online publication, 20 June 2012; doi:10.1038/ki.2012.199.
    Kidney International 06/2012; · 8.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The suitability of in-gel digestion for the characterization of Pt-binding proteins by gel-based bottom-up MS approaches has been evaluated regarding the preservation of Pt-protein bonds during the process. Standard proteins (albumin, transferrin, carbonic anhydrase, myoglobin and cytochome c) incubated with cisplatin were separated by nrSDS-PAGE and in-gel trypsin-digested. The whole in-gel digestion protocol included treatment with reagents such as: ammonium bicarbonate, acetonitrile, formic acid, trypsin as enzyme and alternatively, dithiotreitol and iodoacetamide as reducing and alkylating agents. Digests were analyzed by nHPLC-ESI-LTQ-MS/MS and Pt-peptides were recognized in all the proteins studied on the basis of their isotopic pattern. Only when the reducing and alkylating reagents were used, the amount of detectable Pt-peptides decreased due to the high reactivity of thiol containing reagents towards Pt. Furthermore, the repeated use of acetonitrile could lead to the replacement of ligands originally attached to Pt by CN(-), but does not affect the Pt-protein binding. Platinum-binding sites on the proteins were elucidated from the CID-MS/MS fragmentation spectra and assessed by evaluation of protein structures. Several histidines, cysteines and methionines were identified as platinum binding sites in the different standard proteins. Results were in accordance to those obtained with in-solution digestions.
    Talanta 01/2012; 88:599-608. · 3.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)-based methodology is presented for Pt, Cu, and Zn bioimaging on whole kidney 3 μm sagittal sections from rats treated with pharmacological doses of cisplatin, which were sacrificed once renal damage had taken place. Pt turned out to accumulate in the kidney cortex and corticomedullary junction, corresponding to areas where the proximal tubule S3 segments (the most sensitive cells to cisplatin nephrotoxicity) are located. This demonstrates the connection between platinum accumulation and renal damage proved by histological examination of HE-stained sections and evaluation of serum and urine biochemical parameters. Cu and Zn distribution maps revealed a significant displacement in cells by Pt, as compared to control tissues. A dramatic decrease in the Pt accumulation in the cortex was observed when cilastatin was coadministered with cisplatin, which can be related to its nephroprotective effect. Excellent imaging reproducibility, sensitivity (LOD 50 fg), and resolution (down to 8 μm) were achieved, demonstrating that LA-ICP-MS can be applied as a microscopic metal detector at cellular level in certain tissues. A simple and quick approach for the estimation of Pt tissue levels was proposed, based on tissue spiking.
    Analytical Chemistry 09/2011; 83(20):7933-40. · 5.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: It is known that oral administration of sodium tungstate preserves the pancreatic beta cell function in diabetic rats. Healthy and streptozotocin-induced diabetic rats were treated with sodium tungstate for one, three or six weeks, after which the species of W in serum, were analysed. An increase in serum W with treatment time was observed. After six weeks, the serum W concentration in diabetic rats (70 mg L(-1)) was about 4.6 times higher than in healthy specimens. This different behaviour was also observed for Cu accumulation, while the Zn pattern follows the contrary. The patterns observed in the retention of Cu and Zn may be attributable to a normalization of glycaemia. The speciation analysis of W was performed using 2D separations, including an immunoaffinity packing and a SEC (Size Exclusion Chromatography) column coupled to an ICP-MS (Inductively Coupled Plasma Mass Spectrometry) for elemental detection. Ultrafiltration data together with SEC-ICP-MS results proved that around 80% of serum W was bound to proteins, the diabetic rats registering a higher W content than their healthy counterparts. Most of the protein-bound W was due to a complex with albumin. An unknown protein with a molecular weight higher than 100 kDa was also found to bind a small amount of W (about 2%). MALDI-TOF (Matrix-Assisted Laser Desorption Ionization Time-of-Flight) analysis of the desalted and concentrated chromatographic fractions confirmed albumin as the main protein bound to tungstate in rat serum, while no binding to transferrin (Tf) was detected. The interaction between glutathione and W was also evaluated using standard solutions; however, the formation of complexes was not observed. The stability of the complexes between W and proteins when subjected to more stringent procedures, like those used in proteomic methodologies (denaturing with urea or SDS, boiling, sonication, acid media, reduction with β-mercaptoethanol (BME) or DTT (dithiotreitol) and alkylation with iodoacetamide (IAA), was also evaluated. Our results indicate that the stability of the complexes between W and proteins is not too high enough to remain unaltered during protein separation by SDS-PAGE in denaturing and reducing conditions. However, the procedures for in-solution tryptic digestion and for ESI-MS analysis in MeOH/H(2)O/with 0.1% formic acid could be used for protein identification without large loss of binding between W and proteins.
    Talanta 05/2011; 84(4):1011-8. · 3.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several field trials have been carried out to assess the performance of the passive sampler Chemcatcher as aquatic monitoring technology for inorganic mercury and the organotin pollutants monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in different types of waters across ten locations in Europe. Two version of the sampler were used. One for mercury that consists on 47 mm Empore™ disks of iminodiacetic chelating groups as the receiving phase overlaid by a diffusion membrane of polyethersulphone; and other for organotin compounds comprising a C18 disk and a cellulose acetate membrane. Both membranes were held in a disposable polycarbonate body. The two samplers were calibrated in the laboratory in a previous work to estimate the pollutant concentration. For field sampling, the samplers were deployed for 14 days. In parallel spot samples were periodically collected during the deployment period for comparison purposes. No significant biofouling on the samplers was observed for the locations monitored. In general, water concentrations estimated by Chemcatcher were lower than those found in spot water samples due to the device only collected the soluble bioavailable fraction of target pollutants. However, the pre-concentration capability of Chemcatcher allowed the determination of the tested pollutants at levels where spot sampling fails, even in difficult water bodies such as sewage treatment plants. These advantages lead to consider this emerging methodology as a complementary tool to traditional spot sampling.
    International Journal of Environmental Analytical Chemistry - INT J ENVIRON ANAL CHEM. 01/2011; 91(11):1100-1116.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The characterization of the interaction of platinum drugs with proteins has been previously performed using bottom-up proteomics approaches (enzymatic digestion followed by MS analysis). Nevertheless, the study of the stability of the Pt-protein bonds along the whole process has been obviated for the moment. Herein the suitability of the treatments implied during enzymatic digestion of Pt-protein adducts has been evaluated, focusing on the stability of the Pt bonds. Insulin-cisplatin adducts were generated in vitro and separated from unreacted cisplatin by HPLC, the separation being checked by HPLC-ICP-MS. The chromatographically isolated Pt-insulin adducts have been proved to resist overnight digestion including treatment with Urea, DTT, IAA and trypsin in a Tris buffer. Direct analysis of the peptides generated by nESI-LIT MS allowed the determination of Pt-binding sites in insulin as: B Chain N-terminus, His5, His10, Cys7, Cys19 and A Chain Cys6, Cys7, Cys20. Results have been compared to a previous top-down approach, indicating that more complete information can be obtained with the bottom-up approach. Reactivity of free cysteines has been proved to prevail to N-donor groups, but when cysteines participate in disulfide bonds, their reactivity is comparable to N-donor sites (N-terminus, His). Preliminary results indicate that the use of High Intensity Focused Ultrasound for accelerating the enzymatic digestions is compatible with preserving Pt-protein bonds, allowing a reduction in the total digestion time to 5 min. Pt-containing peptides were fragmented and sequenced by CID, and results were compared with those obtained by the use of ETD, being CID spectra far more informative.
    The Analyst 06/2010; 135(6):1288-98. · 4.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A major area in cancer therapy is the search for protective strategies against cisplatin-induced nephrotoxicity. We investigated the protective effect of cilastatin on cisplatin-induced injury to renal proximal tubular cells. Cilastatin is a specific inhibitor of renal dehydrodipeptidase I (DHP-I), which prevents hydrolysis of imipenem and its accumulation in the proximal tubule. Primary cultures of proximal cells were treated with cisplatin (1-30 microM) in the presence or absence of cilastatin (200 microg/ml). Apoptosis and mitochondrial injury were assessed by different techniques. Cisplatin uptake and DNA binding were measured by inductively coupled plasma spectrometry. HeLa cells were used to control the effect of cilastatin on the tumoricidal activity of cisplatin. Cisplatin increased cell death, apoptotic-like morphology, caspase activation, and mitochondrial injury in proximal tubular cells in a dose- and time-dependent way. Concomitant treatment with cilastatin reduced cisplatin-induced changes. Cilastatin also reduced the DNA-bound platinum but did not modify cisplatin-dependent up-regulation of death receptors (Fas) or ligands (tumor necrosis factor alpha, Fas ligand). In contrast, cilastatin did not show any effects on cisplatin-treated HeLa cells. Renal DHP-I was virtually absent in HeLa cells. Cilastatin attenuates cisplatin-induced cell death in proximal tubular cells without reducing the cytotoxic activity of cisplatin in tumor cells. Our findings suggest that the affinity of cilastatin for renal dipeptidase makes this effect specific for proximal tubular cells and may be related to a reduction in intracellular drug accumulation. Therefore, cilastatin administration might represent a novel strategy in the prevention of cisplatin-induced acute renal injury.
    Journal of Pharmacology and Experimental Therapeutics 04/2010; 334(2):419-29. · 3.89 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Pt-containing drugs are nowadays essential components in cancer chemotherapy. However, drug resistance and side effects limit the efficiency of the treatments. In order to improve the response to Pt-based drugs, different administration strategies or new Pt-compounds have been developed with little success. The reason for this failure could be that the mechanism of action of these drugs is not completely understood. In this way, metallomics studies may contribute to clarify the interactions of Pt-containing drugs within the organism. This review is mainly focused on the role of Analytical Chemistry on the study of the interactions between Pt-based drugs and biomolecules. A summary of the analytical techniques and the most common sample treatment procedures currently used in metallomics studies of these drugs is presented. Both are of paramount importance to study these complex samples preserving the drug-biomolecule interaction. Separation and detection techniques must be carefully selected in order to achieve the intended goals. The use of multidimensional hyphenated techniques is usually necessary for a better understanding of the Pt-based drugs interactions in the organism. An overview of Pt-drugs biological interactions is presented, considering the different sample matrices and the drugs course through the organism. Samples analysed in the included studies are blood, urine, cell cytosol, DNA as well as the drugs themselves and their derivatives. However, most of these works are based on in vitro experiments or incubations of standards, leading in some cases to contradictory results depending on the experimental conditions used. Though in vivo experiments represent a great challenge due to the high complexity and the low concentrations of the Pt-adducts in real samples, these studies must be undertaken to get a deeper understanding of the real interactions concerning Pt-containing drugs.
    Metallomics 01/2010; 2(1):19-38. · 4.10 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The interaction of the antitumor drug cisplatin with insulin was studied using a top-down mass spectrometric approach. In vitro incubations were prepared under acidic and physiological conditions at different insulin/cisplatin molar ratios for different incubation times. Size exclusion chromatography-inductively coupled plasma mass spectrometry (SEC-ICPMS) analysis enabled the specific detection of platinum containing species attributed to the binding of the drug to the protein. Further analysis through matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and nanoelectrospray ionization mass spectrometry using a linear ion trap (nESI-LIT-MS) allowed the identification of platinated mono-, di-, and even triadducts in the incubations. Platinum binding sites were identified by CID-MS(n) as B chain N-terminus, His5, and probably His10 residues, which turned out to be the same, regardless of the incubation conditions. Evidence on the binding of Pt to B chain Cys7 was also observed. Working with the LIT zoom scan mode provides enough resolution to discern the isotopic pattern for both precursor and fragment ions, allowing the differentiation of platinum-containing ions. The elucidation of platinum binding sites in a native protein through a top-down approach has been performed for the first time with this type of instrument.
    Analytical Chemistry 04/2009; 81(9):3507-16. · 5.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A passive sampler (Chemcatcher) consisting of a 47 mm Emporetrade mark chelating disk (CHE) with iminodiacetic groups as the receiving phase overlaid with a diffusion membrane was developed and calibrated for the monitoring of Hg in water. Three different diffusion membranes including cellulose acetate (CA), polyethersulphone (PS) and cellulose dialysis membrane (D) were tested. The best performance was obtained with the CHE-PS tandem. The effective sampling rate of the device (R(s), L day(-1)) is defined as the equivalent volume of water extracted per unit time, and is analyte specific and can be determined experimentally in a flow-through tank. Effects of water temperature and turbulence on the uptake rate of Hg were assessed under controlled laboratory conditions. Sampling rates were in the range of 0.029-0.091 L day(-1). An increase in sampling rate with turbulence was demonstrated. The detection limit of the sampler obtained in flowing waters ranged between 2.2 and 2.9 ng L(-1)Hg. The performance of Chemcatcher was tested alongside spot water sampling in a 14-day field deployment at two locations on the Valdeazogues River, Almadén, Spain. In general, the Hg concentration estimated by the Chemcatcher was lower than that found in spot water samples collected over the same period. This may be explained by the behaviour of this sampler that measures only the labile fraction of Hg in water, and this will exclude some species. However, Chemcatcher preconcentrates Hg allowing its determination in some places where its concentration is below the detection limit of spot sampling.
    Talanta 03/2009; 77(4):1483-9. · 3.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An integrative passive sampler (Chemcatcher) consisting of a 47 mm C18 Empore disk as the receiving phase overlaid with a thin cellulose acetate diffusion membrane was developed and calibrated for the measurement of time-weighted average water concentrations of organotin compounds [monobutyltin (MBT), dibutyltin (DBT), tributlytin (TBT) and triphenyltin (TPhT)] in water. The effect of water temperature and turbulence on the uptake rate of these analytes was evaluated in the laboratory using a flow-through tank. Uptake was linear over a 14-day period being in the range: MBT (3-23 mL day(-1)), DBT (40-200 mL day(-1)), TBT (30-200 mL day(-1)) and TPhT (30-190 mL day(-1)) for all the different conditions tested. These sampling rates were high enough to permit the use of the Chemcatcher to monitor levels of organotin compounds typically found in polluted aquatic environments. Using gas chromatography (GC) with either ICP-MS or flame photometric detection, limits of detection for the device (14-day deployment) for the different organotin compounds in water were in the range of 0.2-7.5 ng L(-1), and once accumulated in the receiving phase the compounds were stable over prolonged periods. Due to anisotropic exchange kinetics, performance reference compounds could not be used with this passive sampling system to compensate for changes in sampling rate due to variations in water temperature, turbulence and biofouling of the surface of the diffusion membrane during field deployments. The performance of the Chemcatcher was evaluated alongside spot water sampling in Alicante Habour, Spain which is known to contain elevated levels of organotin compounds. The samplers provided time-weighted average concentrations of the bioavailable fractions of the tin compounds where environmental concentrations fluctuated markedly in time.
    Analytica chimica acta 07/2008; 618(2):157-67. · 4.31 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Antitumoral Pt-containing drugs present side effects like nephrotoxicity and ototoxicity. Several systematic experiments have been carried out with Wistar rats treated with cisplatin, carboplatin, and oxaliplatin to study Pt-drugs accumulation and elimination, and Pt-biomolecule distribution in the cells and cytosols of ear, kidney, and liver. Inductively coupled plasma-mass spectrometry (ICP-MS) analysis shows a cisplatin accumulation capability between oxaliplatin (the highest) and carboplatin (the lowest). The maximum concentration of Pt in all the organs studied was achieved around the first week after cisplatin treatment. During the first 30 days, the elimination was very fast, decreasing in the subsequent 60 days in all the organs. Analysis of cytosols by liquid chromatography (LC)-ICP-MS showed an analogous behavior. In most samples, the distribution of the three drugs in the cellular and cytosolic fractions was similar for all the tissues. For kidney and ear, approximately 60% and 30%, respectively, of the metal accumulated was present in the cytosol, the cytosolic fractions smaller than 50 KDa being especially important. Cisplatin-biomolecule interaction strength under denaturing conditions was evaluated by LC-ICP-MS and showed a quite strong bond.
    Journal of analytical toxicology 04/2008; 32(2):140-6. · 2.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Oral administration of sodium tungstate is an effective treatment for type 1 and 2 diabetes in animal models; it does not incur significant side effects, and it may constitute an alternative to insulin. However, the mechanism by which tungstate exerts its observed metabolic effects in vivo is still not completely understood. In this work, serum-containing proteins which bind tungstate have been characterized. Size exclusion chromatography (SEC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) with a Phenomenex Bio-Sep-S 2000 column and 20 mM HEPES and 150 mM NaCl at pH 7.4 as the mobile phase was chosen as the most appropriate methodology to screen for tungsten-protein complexes. When human serum was incubated with tungstate, three analytical peaks were observed, one related to tungstate-albumin binding, one to free tungstate, and one to an unknown protein binding (MW higher than 300 kDa). Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometric analysis of the tungsten-containing fractions collected from SEC-ICP-MS chromatograms, after desalting and preconcentration processes, confirmed the association of tungstate with albumin and the other unknown protein. [figure: see text]
    Analytical and Bioanalytical Chemistry 02/2008; 390(1):29-35. · 3.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The judicious use of cis-Pt as an intravenously administrable Pt(II)drug for chemotherapy requires the evaluation of its interactions with blood proteins. Therefore, the combined use of modern analytical chemical speciation and of analytical proteomics approaches to study these interactions is described here. The method involves incubation of cis-Pt with standard proteins and human serum samples. The separation of the proteins is conducted by liquid chromatography in an anion exchange column (Mono Q). Simultaneous molecular detection by UV absorption (280 nm) and elemental detection (195Pt) using inductively coupled plasma mass spectrometry (ICP-MS) are performed. Using this set-up, the effects of the incubation time as well as the drug concentration on cis-Pt interactions with transferrin, albumin and innmunoglobulin G were studied. In addition, the nature of interactions was also investigated by means of electrospray mass spectrometry (ESI-Q-TOF) of the intact protein. Transferrin and albumin showed different interactions, binding one and four cisplatin molecules, respectively. Also, some typical proteomic studies were initiated by tryptic digesting the transferrin and albumin cis-Pt complexes followed by capillary-LC-ICP-MS and ESI-Q-TOF parallel detection of the peptides obtained. The capLC-ICP-MS chromatogram provided clear evidence of Pt-containing peptides remaining after tryptic digestion.
    Journal of Analytical Atomic Spectrometry 01/2008; 23:378. · 3.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Several configurations of receiving disks and diffusion membranes were tested for monitoring mercury and organotin compounds (monobutyltin, dibutyltin, tributyltin, and triphenyltin) in water with a passive sampler. This passive sampler is based on the diffusion of these compounds through a specific diffusion-limiting membrane and their subsequent accumulation on a specific receiving phase, all materials being commercially available. The proposed sampler for inorganic mercury comprises a 47-mm Empore™ chelating disk as receiving phase and polyethersulfone as diffusion membrane. For monitoring organotins, the receiving phase is a 47-mm Empore™ C18 disk, and the diffusion membrane is cellulose acetate. ICP-MS and GC-ICPMS/GC-FPD were used for inorganic mercury and the organotins analysis, respectively. The effects of environmental variables such as pH and salinity that could influence accumulation of test substances in receiving phase were studied. Linear uptake for all compounds was observed for at least 14 days of exposure at a constant aqueous analyte concentration in a flow-through system under controlled conditions of temperature, turbulence, and analyte concentration. Compound-specific sampling rates at 11°C and simulated water turbulence of 40cms varied between 0.018 and 0.137Ld. Compounds collected by the sampler exhibited detection limits ranging between 0.7 and 5.9ngL. The feasibility of using these samplers in the field was tested in a polluted commercial harbour. The behaviour of the samplers to monitor target compounds was compared with those obtained from spot samples of water taken throughout the field deployment period. Data from laboratory studies and field trial support the feasibility of these samplers to measure the freely dissolved fraction of these important target analytes in water.
    International Journal of Environmental Analytical Chemistry - INT J ENVIRON ANAL CHEM. 01/2008; 88(2):75-90.