Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 114
Filtrar
1.
ESMO Open ; 8(2): 101201, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36965262

RESUMEN

INTRODUCTION: Body surface area (BSA)-based dosing of 5-fluorouracil (5-FU) results in marked inter-individual variability in drug levels, whereas determination of plasma 5-FU concentration and area under the curve (AUC) is a more precise dosing method but has not been integrated into clinical routine. We conducted a multicenter, prospective study to study 5-FU AUC distributions and assess clinical factors predicting therapeutic dosing in patients receiving BSA-dosed 5-FU. METHODS: Between June 2017 and January 2018, a total of 434 patients receiving continuous, infusional BSA-dosed 5-FU from 37 sites in Germany were included. Plasma 5-FU concentration and AUC were measured in venous blood samples at steady state. The primary objective was to determine 5-FU AUC distributions in relation to the target range, which is defined as 20-30 mg × h/l. The second objective was to explore clinical parameters that correlate with achievement of 5-FU AUC target range. RESULTS: The primary tumor was mainly located in the gastrointestinal tract (96.3%), with colorectal cancer being the most common (71.2%) tumor entity. 5-FU was administered as monotherapy (8.1%) or as part of FOLFOX (33.2%), FOLFIRI (26.3%), or other regimens (12.4%). Treatment setting was adjuvant (31.3%) or metastatic (64.5%). The median AUC was 16 mg × h/l. Only 20.3% of patients received 5-FU treatment within the target range, whereas the majority of patients (60.6%) were underdosed and 19.1% of patients were overdosed. In the univariate logistic regression, treatment setting was the only clinical parameter that significantly correlated with achievement of the target range. Patients treated in the metastatic setting had a 2.1 (95% confidence interval 1.186-3.776, P = 0.011) higher odds to reach the target range compared with patients treated in the adjuvant setting. CONCLUSIONS: The majority of patients received suboptimal doses of 5-FU using BSA dosing. Therapeutic drug monitoring of 5-FU is an option for optimized individualized cancer therapy and should be integrated into the clinical practice.


Asunto(s)
Neoplasias Colorrectales , Fluorouracilo , Humanos , Fluorouracilo/uso terapéutico , Fluorouracilo/efectos adversos , Estudios Prospectivos , Monitoreo de Drogas/métodos , Neoplasias Colorrectales/tratamiento farmacológico , Alemania/epidemiología
2.
Microbiol Res ; 260: 127012, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35430488

RESUMEN

Recent advances have highlighted probiotic role in preventing colorectal cancer, by promoting differentiation, inhibiting proliferation, and inducing apoptosis in colonocytes. Here, three ascertained probiotics (L. rhamnosus GG ATCC 53103, L. reuterii DSM 17938 and L. johnsonii LC1) and four food-isolated putative probiotics (L. plantarum S2, L. plantarum O2, L. pentosus S3, L. rhamnosus 14E4) were investigated for their ability to adhere to HT29 cancer cells and to inhibit their and the chemoresistant counterpart (HT29-dx cells) proliferation. Three putative probiotics (S2, S3 and 14E4) were able to decrease viability of both sensitive and chemo-resistant HT-29 cells. Supposing this effect related to secreted metabolites (namely short chain fatty acids (SCFA), exopolysaccharides (EPS) and extracellular proteins) we tested the efficacy of extracellular extracts and butyrate with or without the chemotherapeutic agent doxorubicin (DOXO) (10 µM, 4 h). Increased production of mitochondrial reactive oxygen species (ROS) in HT29 and HT29-dx cells was observed. Moreover, cell exposure to DOXO (10 µM, 24 h) and extracellular extracts (48 h) reduced cell viability. Comparative phenotypic and secretome analyses on the effective/non effective strains, revealed quantitative/qualitative differences in EPS content and protein profiles, suggesting that P40, phage-tail-like and capsid-like proteins may be also involved. These results suggest that food-isolated bacteria releasing bioactive compounds (butyrate, EPS and peculiar proteins) may control cancer cell proliferation and improve their response to chemotherapy.


Asunto(s)
Neoplasias , Probióticos , Butiratos/farmacología , Supervivencia Celular , Células HT29 , Humanos , Extractos Vegetales , Probióticos/farmacología
4.
Plant Biol (Stuttg) ; 22(3): 404-409, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32027456

RESUMEN

Caleosins are involved in several cellular and biological processes that are closely associated with the synthesis, degradation and stability of oil bodies (OB). Because of the importance and the multiple roles of these OB-associated proteins, in silico identification of sequences corresponding to putative caleosins in the hazelnut genome has been performed, and the association with seed OB was verified using a proteomic approach. Five full-length sequences (CavCLO-H1, CavCLO-H2, CavCLO-H3, CavCLO-L1, CavCLO-L2), belonging to the two groups of caleosins (H and L), have been identified in the hazelnut genome. The number of identified caleosins is in agreement with that previously observed in other plant species, confirming that caleosins comprise small gene families in plants. A proteomic approach allowed us to verify only the presence of CavCLO-H1 in hazelnut OB, suggesting that several members inside this family could have different roles during plant growth and development. In silico analysis also suggests that CavCLO-H1 may act as a peroxygenase.


Asunto(s)
Proteínas de Unión al Calcio , Corylus , Gotas Lipídicas , Proteínas de Plantas , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Corylus/genética , Corylus/crecimiento & desarrollo , Genoma de Planta/genética , Gotas Lipídicas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteómica
6.
Faraday Discuss ; 208(0): 227-242, 2018 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-29808205

RESUMEN

We looked for the active hydrogen species in a highly dispersed and very homogeneous 5 wt% Pt/C industrial catalyst (Pt particle mean diameter of 2.0 ± 0.5 nm) for hydrogenation reactions, by coupling H2 adsorption measurements with Inelastic Neutron Scattering (INS). Taking advantage of the enormous progress undergone by INS instruments, we succeeded in collecting INS spectra of unprecedented quality that allowed us to: (1) demonstrate that the Pt nanoparticles are mainly located at the regular edges of the sp2 graphitic domains on the activated carbon; (2) validate that most of the H2 physisorbed on the carbon is side-on adsorbed; (3) detect for the first time H2 molecules adsorbed on hydride-covered Pt nanoparticles; (4) observe Pt-hydrides (on the Pt/C catalyst with the lowest Pt loading among those investigated by INS so far) and (5) provide evidence for the occurrence of spillover of atomic hydrogen from the Pt surface to unsaturated reactive sites located at the irregular borders of the sp2 domains on the activated carbon.

7.
Mol Omics ; 14(2): 134, 2018 04 16.
Artículo en Inglés | MEDLINE | ID: mdl-29634053

RESUMEN

Correction for 'Selenium effects on the metabolism of a Se-metabolizing Lactobacillus reuteri: analysis of envelope-enriched and extracellular proteomes' by E. Mangiapane et al., Mol. BioSyst., 2014, 10, 1272-1280.

8.
Dalton Trans ; 47(4): 1062-1070, 2018 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-29230462

RESUMEN

Metal-organic frameworks of general composition [M6(OH)4(O)4(PDC)6-x(Cl)2x(H2O)2x] with M = Zr, Ce, Hf; PDC2- = 2,5-pyridinedicarboxylate and 0 ≤ x ≤ 2 were obtained under reflux using formic, nitric or acetic acid as an additive. Rietveld refinements carried out using a fixed occupancy of the linker molecules according to the results of thermogravimetric measurements confirmed that the MOFs crystallize in the UiO-66 type structure and demonstrate that the structural models describe the data well. Further characterization was carried out by NMR spectroscopy, thermogravimetric analysis, Zr K-edge EXAFS- and Ce L3-edge XANES measurements. To highlight the influence of the additional nitrogen atom of the pyridine ring, luminescence and vapour sorption measurements were carried out. The hydrophilisation of the MOFs was shown by the adsorption of water at lower p/p0 (<0.2) values compared to the corresponding BDC-MOFs (0.3). For water and methanol stability cycling adsorption experiments were carried out to evaluate the MOFs as potential adsorbents in heat transformation applications.

10.
Chem Sci ; 8(10): 6836-6851, 2017 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-29147509

RESUMEN

The small pore Cu-CHA zeolite is attracting increasing attention as a versatile platform to design novel single-site catalysts for deNO x applications and for the direct conversion of methane to methanol. Understanding at the atomic scale how the catalyst composition influences the Cu-species formed during thermal activation is a key step to unveil the relevant composition-activity relationships. Herein, we explore by in situ XAS the impact of Cu-CHA catalyst composition on temperature-dependent Cu-speciation and reducibility. Advanced multivariate analysis of in situ XANES in combination with DFT-assisted simulation of XANES spectra and multi-component EXAFS fits as well as in situ FTIR spectroscopy of adsorbed N2 allow us to obtain unprecedented quantitative structural information on the complex dynamics during the speciation of Cu-sites inside the framework of the CHA zeolite.

11.
Phys Chem Chem Phys ; 19(40): 27489-27507, 2017 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-28975938

RESUMEN

An X-ray absorption spectroscopy study of the UiO-67 Pt functionalized metal organic frameworks (MOFs) demonstrates that under appropriate conditions, at least two types of catalytically active sites can be formed in the cavities of the MOF: isolated Pt-complexes and Pt nanoparticles (Pt-NPs). Both pre-made linker synthesis (PMLS) and post-synthesis functionalization (PSF) methods were adopted. XAS was used to monitor the temperature-dependent behaviour of UiO-67-Pt while heating from RT to 623 K, in different gas feeds (pure He, 3% H2/He and 10% H2/He). We collected static in situ Pt LIII XANES and EXAFS spectra at room temperature (RT) before and after the thermal treatment, as well as spectra acquired under operando conditions upon heating. Under 10% H2/He thermal treatment, we unambiguously detected Pt-NP formation which has been followed by a parametric EXAFS analysis of the data collected during temperature programmed H2-reduction (TPR), using the Einstein model to predict the temperature dependence of the Debye-Waller factors. Conversely, in pure He flow, the only significant change observed during TPR is the progressive decrease of the Pt-Cl single scattering contribution, leading to the conclusion that the Pt grafted to the bpydc-linkers remains naked. Advanced EXAFS/TEM analysis allowed us to quantify the fraction of Pt in the form of Pt-NPs, values that have been quantitatively confirmed by linear combination analysis of the XANES spectra. In situ XANES/EXAFS study was supported by ex situ XRPD and BET analyses, confirming the framework stability and testifying a loss of the internal volume after TPR due to the formation of Pt-NPs insides the MOF pores, more relevant in the sample where smaller Pt-NPs were formed.

12.
Faraday Discuss ; 201: 265-286, 2017 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-28621776

RESUMEN

The exceptional thermal and chemical stability of the UiO-66, -67 and -68 classes of isostructural MOFs [J. Am. Chem. Soc., 2008, 130, 13850] makes them ideal materials for functionalization purposes aimed at introducing active centres for potential application in heterogeneous catalysis. We previously demonstrated that a small fraction (up to 10%) of the linkers in the UiO-67 MOF can be replaced by bipyridine-dicarboxylate (bpydc) moieties exhibiting metal-chelating ability and enabling the grafting of Pt(ii) and Pt(iv) ions in the MOF framework [Chem. Mater., 2015, 27, 1042] upon interaction with PtCl2 or PtCl4 precursors. Herein we extend this functionalization approach in two directions. First, we show that by controlling the activation of the UiO-67-Pt we can move from a material hosting isolated Pt(ii) sites anchored to the MOF framework with Pt(ii) exhibiting two coordination vacancies (potentially interesting for C-H bond activation) to the formation of very small Pt nanoparticles hosted inside the MOF cavities (potentially interesting for hydrogenation reactions). The second direction consists of the extension of the approach to the insertion of Cu(ii), obtained via interaction with CuCl2, and exhibiting interesting redox properties. All materials have been characterized by in situ X-ray absorption spectroscopy at the Pt L3- and Cu K-edges.

13.
Chem Sci ; 6(1): 548-563, 2015 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-28936309

RESUMEN

Cu-SSZ-13 is a highly active NH3-SCR catalyst for the abatement of harmful nitrogen oxides (NO x , x = 1, 2) from the exhausts of lean-burn engines. The study of Cu-speciation occurring upon thermal dehydration is a key step for the understanding of the enhanced catalytic properties of this material and for identifying the SCR active sites and their redox capability. Herein, we combined FTIR, X-ray absorption (XAS) and emission (XES) spectroscopies with DFT computational analysis to elucidate the nature and location of the most abundant Cu sites in the activated catalyst. Different Cu species have been found to be dominant as a function of the dehydration temperature and conditions. Data analysis revealed that the dehydration process of Cu cations is essentially completed at 250 °C, with the formation of dehydrated [CuOH]+ species hosted in close proximity to 1-Al sites in both d6r and 8r units of the SSZ-13 matrix. These species persist at higher temperatures only if a certain amount of O2 is present in the gas feed, while under inert conditions they undergo virtually total "self-reduction" as a consequence of an OH extra-ligand loss, resulting in bi-coordinated bare Cu+ cations. Synchrotron characterization supported by computational analysis allowed an unprecedented quantitative refinement of the local environment and structural parameters of these Cu(ii) and Cu(i) species.

14.
Mol Biosyst ; 10(6): 1272-80, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24481235

RESUMEN

Selenium (Se) has received great attention in the last few years, as it is considered to be essential for human health (prevention of viral infections, heart diseases and ageing-related diseases). Se deficiency can be counteracted by the administration of selenium-enriched probiotics that are able to convert inorganic selenium into less toxic and more bio-available organic forms. This study was performed on Lactobacillus reuteri Lb2 BM DSM 16143, a probiotic LAB previously demonstrated to be able to fix Se into selenocysteines. The aim was to assess Se influence on its metabolism, by a 2-DE proteomic approach, on two different cellular districts: envelope-enriched and extracellular proteomes. While in the envelope-enriched fraction 15 differentially expressed proteins were identified, in the extracellular proteome no quantitative difference was detected. However, at a molecular level, we observed the insertion of Se into selenocysteine, exclusively under the stimulated conditions. The obtained results confirmed the possibility to use L. reuteri Lb2 BM DSM 16143 as a carrier of organic Se that can be easily released in the gut becoming available for the human host.


Asunto(s)
Proteínas Bacterianas/metabolismo , Limosilactobacillus reuteri/metabolismo , Selenio/metabolismo , Selenocisteína/metabolismo , Proteínas Bacterianas/química , Ácidos y Sales Biliares/farmacología , Regulación Bacteriana de la Expresión Génica , Limosilactobacillus reuteri/efectos de los fármacos , Probióticos , Proteómica
15.
Chemosphere ; 86(9): 875-82, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22119417

RESUMEN

The aim of this study was to develop a preliminary characterization of the biological responses of Hediste diversicolor to polycyclic aromatic hydrocarbons (PAHs) under controlled laboratory conditions. In order to test the effects of PAH exposure, a battery of biomarkers was applied to the polychaetes by exposing them to sublethal concentrations of benzo[a]pyrene (0.1 and 0.5 mg L(-1)) for 10d under laboratory conditions. The battery of biomarkers tested included oxidative stress biomarkers (glutathione content, enzymatic activities of catalase, glutathione S-transferases, glutathione reductase, glutathione peroxidases), total oxyradical scavenging capacity (TOSC) toward peroxyl and hydroxyl radicals and activity of acyl CoA oxidase (AOX) as a marker of peroxisome proliferation measured in the entire body; lipofuscin and neutral lipid accumulations and levels of Ca(2+)-ATPase activity analyzed in the intestinal epithelium; lysosomal membrane stability and genotoxic effects measured as DNA strand breaks and frequency of micronuclei in coelomocytes. Chemical analyses were also carried out to verify the polychaete's benzo[a]pyrene (B[a]P) bioaccumulation levels after the exposure period. The results obtained indicate that B[a]P caused significant changes in most of the parameters measured in H. diversicolor. Biological responses to the organic compound were particularly significant for the biomarkers measured in the intestinal epithelium and in coelomocytes, emphasizing that these tissues were more affected during our experimental conditions. Considering the key trophic role of this benthic species in estuarine and coastal ecosystems, this study confirmed that H. diversicolor is an appropriate bioindicator of organic contamination.


Asunto(s)
Benzo(a)pireno/metabolismo , Monitoreo del Ambiente/métodos , Poliquetos/metabolismo , Hidrocarburos Policíclicos Aromáticos/metabolismo , Contaminantes Químicos del Agua/metabolismo , Animales , Benzo(a)pireno/análisis , Benzo(a)pireno/toxicidad , Biomarcadores/metabolismo , Catalasa/metabolismo , Glutatión/metabolismo , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/metabolismo , Glutatión Transferasa/metabolismo , Pruebas de Mutagenicidad , Estrés Oxidativo , Hidrocarburos Policíclicos Aromáticos/análisis , Hidrocarburos Policíclicos Aromáticos/toxicidad , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
16.
Dalton Trans ; 39(36): 8437-49, 2010 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-20717598

RESUMEN

The comprehensive understanding of the composition, behaviour and reactivity of a catalyst used inside industrial plants is an extremely hard task that is rarely achieved. It requires the use of different spectroscopic techniques, applied under in situ or in operando conditions, and combined with the investigation of the catalyst activity. Often the operating experimental conditions are different from technique to technique and the different results must be compared with care. In the present contribution, we combined in situ XANES/EXAFS, IR spectroscopy of adsorbed CO, CO chemisorption and catalytic tests performed using a pulse reactor in depletive mode. This multitechnical approach resulted in the understanding of the role that dopants (LiCl, KCl, CsCl, MgCl(2) LaCl(3)) have in the nature, relative fraction, reducibility and dispersion of Cu-phases on CuCl(2)/gamma-Al(2)O(3) catalysts for oxychlorination reaction, a key step of the PVC chemistry. In the undoped catalyst two Cu phases coexist: Cu-aluminate and supported CuCl(2), being the latter the only active one [J. Catal., 2000, 189, 91]. EXAFS and XANES highlighted that all dopants contribute more or less efficiently in increasing the fraction of the active copper species, that reaches a value of almost 100% in the case of MgCl(2) or LaCl(3). EXAFS directly, and IR indirectly, proved that the addition of KCl or CsCl (and less efficiently of LiCl) results in the formation of mixed CuK(x)Cl(2+x) or CuCs(x)Cl(2+x) phases, so altering the chemical nature of the active phase. XANES spectroscopy indicates that addition of MgCl(2) or LaCl(3) does not affect the reducibility by ethylene (under static conditions) of the active CuCl(2) phase and that the reducibilility of the new copper-dopant mixed chloride are in the order CuCl(2) > CuLi(x)Cl(2+x) > CuK(x)Cl(2+x) > CuCs(x)Cl(2+x). However, when reduction is done inside a pulse reactor, a more informative picture comes out. The last technique is able to differentiate all samples, and their ability to be reduced by ethylene resulted in the order: La- > Mg- > Li-doped > undoped > K- > Cs-doped catalyst. To understand this apparent discrepancy the dispersion of the active phase, measured by CO chemisorption, was needed: it has been found that addition of LiCl increases enormously the dispersion of the active phase, LaCl(3) significantly and MgCl(2) barely, while addition of both KCl and CsCl results in a decrease of the surface area of the active phase. The mechanism of the enhancing effect of La and Mg on catalytic activity is still not clear, but it could be associated to the modification that they induce to the support surface: the Cu is so highly dispersed that almost all is in direct contact with support surface. It is finally worth noticing that the previous EXAFS and XANES study allowed us to refer the chemisorption data to the active phase only, while the IR study allowed us to fix the Cu(+)/CO surface stoichiometry. Summarizing the use of a multidisciplinary approach has been the conditio sine qua non (mandatory condition) to understand the complex role that the different additives have on the active phase of the CuCl(2)/gamma-Al(2)O(3) catalysts for ethylene oxychlorination.


Asunto(s)
Óxido de Aluminio/química , Cobre/química , Etilenos/química , Catálisis , Cesio/química , Cloruros/química , Cloruro de Litio/química , Cloruro de Magnesio/química , Oxidación-Reducción , Cloruro de Potasio/química , Espectroscopía de Absorción de Rayos X
17.
Phys Chem Chem Phys ; 12(21): 5605-18, 2010 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-20428577

RESUMEN

The understanding, at the atomic level, of the role played by additives (dopants or promoters) in the chemistry of an industrial catalyst is a very complex and difficult task. We succeeded in this goal for the ethylene oxychlorination catalyst (CuCl(2)/gamma-Al(2)O(3)), used to produce dichloroethane, a key intermediate of the polyvinyl chloride chemistry (PVC). Among the most used additives for both fluid and fixed beds technologies (LiCl, KCl, CsCl, MgCl(2), LaCl(3), CeCl(4)) we have been able to highlight that KCl, and CsCl, forming in reaction conditions a mixed phase with CuCl(2), strongly modify the catalyst behaviour. In particular, these additives are able to displace the rate determining step from the CuCl oxidation (undoped catalyst) to the CuCl(2) reduction. This results from the decrease of the rate of the latter reaction, thus the overall activity of the system. For all remaining additives the rate determining step remains the CuCl oxidation, as for the undoped catalyst. These results have been obtained coupling the catalyst activity monitored with a pulse reactor working in both non-depletive and depletive modes with time resolved XANES spectroscopy performed under in operando conditions (i.e. coupled with mass spectrometry). Formation of CuK(x)Cl(2+x) and CuCs(x)Cl(2+x) mixed phases has been proved monitoring the Cu(II) d-d transitions with UV-Vis spectrometer and the CO stretching frequency of carbon monoxide adsorbed on reduced catalyst by in situ IR spectroscopy. Finally, of high relevance is the observation that the fully oxidized catalyst is inactive. This unexpected evidence highlight the role of coordinatively unsaturated Cu(I) species in adsorbing ethylene on the catalyst surface indicating that copper, in the working catalyst, exhibits a (I)/(II) mixed valence state.

18.
Endoscopy ; 41(4): 316-22, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19340735

RESUMEN

BACKGROUND AND STUDY AIMS: Individuals carrying germline mutations in one of the genes responsible for hereditary nonpolyposis colon cancer (HNPCC) have a lifetime risk of up to 80 % of developing colorectal cancer. As there is evidence for a higher incidence of flat adenomatous precursors and because an accelerated adenoma-carcinoma sequence has been postulated for these patients, early detection of these lesions is essential. It was the aim of the present study to assess the detection rate of polypoid lesions by comparing chromocolonoscopy with standard white light colonoscopy and narrow-band imaging (NBI) colonoscopy. PATIENTS AND METHODS: 109 patients were included (98 with a functionally relevant mutation in a mismatch repair gene, 11 fulfilling the strict Amsterdam criteria). In 47 patients, standard colonoscopy was followed by chromocolonoscopy with indigo carmine. In 62 patients, NBI was performed first followed by chromocolonoscopy. RESULTS: A total of 128 hyperplastic and 52 adenomatous lesions were detected. In the first series, 0.5 lesions/patient were identified by standard colonoscopy and 1.5 lesions/patient by chromocolonoscopy ( P < 0.001). In the second series, 0.7 lesions/patient were detected by NBI colonoscopy and 1.8 lesions/patient by chromocolonoscopy ( P = 0.01). At least one adenoma was detected in 15 % of patients by both standard and NBI colonoscopy compared with 28 % of patients by chromocolonoscopy. CONCLUSION: According to this study, chromocolonoscopy detects significantly more hyperplastic and, in particular, adenomatous lesions than standard white light colonoscopy or NBI.


Asunto(s)
Adenoma/diagnóstico , Neoplasias del Colon/diagnóstico , Colonoscopía/métodos , Neoplasias Colorrectales Hereditarias sin Poliposis/diagnóstico , Tamizaje Masivo/métodos , Lesiones Precancerosas/diagnóstico , Adenoma/patología , Adenoma/prevención & control , Adulto , Disparidad de Par Base , Colon/patología , Neoplasias del Colon/patología , Neoplasias del Colon/prevención & control , Pólipos del Colon/diagnóstico , Pólipos del Colon/patología , Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Neoplasias Colorrectales Hereditarias sin Poliposis/patología , Neoplasias Colorrectales Hereditarias sin Poliposis/prevención & control , Colorantes , Diagnóstico Diferencial , Detección Precoz del Cáncer , Mutación de Línea Germinal , Humanos , Hiperplasia/diagnóstico , Hiperplasia/patología , Carmin de Índigo , Persona de Mediana Edad , Lesiones Precancerosas/patología
19.
Langmuir ; 25(11): 6476-85, 2009 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-19348495

RESUMEN

Adsorption of N2 at 77 K and scanning electron microscopy have been used to measure the changes in the support morphology, at nano- and microscale level, along the processes involved in the preparation of a supported Pd catalyst: Pd deposition, doping, and thermal treatments. Among the investigated supports, viz., activated carbons, gamma-Al2O3, SiO2, and SiO2-Al2O3 (SA), the SA one was found particularly sensitive to these processes, as a result of its high plasticity and reactivity. Involved processes can be summarized as follows: (i) During the Pd deposition, the support itself is partially dissolved and removed as a result of both the basicity of the precipitating agent and the final washing. (ii) When the undoped sample is thermally treated up to 823 K, only modest phenomena are observed. (iii) Upon doping with potassium carbonate, the support dissolution continues, and the greater the carbonate concentration, the greater the dissolution extent. In this case the dissolved material is not removed, but reprecipitates (partially outside the pores), during the subsequent drying at 393 K. (iv) When doped samples are thermally treated, the reaction between carbonate and support causes the mobilization of the support itself, with sintering phenomena that can reach the total collapse of the porous structure. The starting temperature of the pore collapse decreases with increasing potassium carbonate concentration. The modification of the support influences, directly or indirectly, the surface properties and the availability of Pd particles that can be doped or even covered by materials from support and made more or less accessible or even inaccessible by pore narrowing, widening, or blocking.

20.
Cardiovasc Intervent Radiol ; 32(1): 155-8, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18506520

RESUMEN

Hydrofluoric acid (HF) is a colorless corrosive acid used in different industrial branches. Exposure to HF typically results from spills, and most often the hand or fingers are involved. Tissue damage through cutaneous HF exposure occurs through corrosive burns due to the free hydrogen ions and through skin penetration of the fluoride ions, causing a depletion of calcium in the deep tissue layers, ultimately leading to cell death and tissue necrosis. Treatment of HF burns consists of thoroughly flushing the exposed area with water and applying calcium gluconate gel to the skin. If topical treatment does not suffice, subcutaneous injections, as well as intravascular--both intravenous and intra-arterial--calcium gluconate therapy, have been advocated. We report for the first time a case of HF burn of the hand and digits associated with vasospasm. Pain and vasospasm were successfully treated by repeated intra-arterial calcium gluconate injection. We conclude that intra-arterial calcium gluconate injection is a successful and well-tolerated therapy for HF burn associated with Raynaud's syndrome. Intra-arterial injection allows for well-controlled delivery of therapy as well as assessment of the vascular status.


Asunto(s)
Quemaduras Químicas/tratamiento farmacológico , Gluconato de Calcio/administración & dosificación , Traumatismos de la Mano/tratamiento farmacológico , Mano/irrigación sanguínea , Ácido Fluorhídrico/efectos adversos , Accidentes de Trabajo , Adulto , Angiografía , Femenino , Traumatismos de la Mano/inducido químicamente , Traumatismos de la Mano/diagnóstico por imagen , Humanos , Infusiones Intraarteriales
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...