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21.
The stromal microenvironment is pivotal to prostate physiology and malign transformation. Diabetes leads to testosterone withdrawal and affects the prostate stromal compartment and smooth muscle cells in a similar way to that observed after castration. However the response of these cells and their involvement in extracellular matrix remodeling is not satisfactorily understood. We investigated the changes caused in the short term (one week) by alloxan-induced diabetes in the stromal components of the rat ventral prostate (VP) with an emphasis on morphological alterations of stromal cells, their conversion to a myofibroblast phenotype and the remodeling of extracellular matrix and the influence of insulin therapy. Adult male Wistar rats were assigned into untreated diabetic (n=12), insulin-treated (n=8) diabetic and control (n=10) groups. Diabetes was induced by means of the injection of alloxan (40 mg/kg b.w.), while the control animals received saline solution only. Insulin (5 UI) was administered daily for one week after diabetes diagnosis. Testosterone and estrogen plasma levels were determined. VP was analyzed using transmission electron microscopy. The main stromal cells were identified by means of light microscopy, using immunocytochemistry for specific markers - vimentin for fibroblasts, α-actin for smooth muscle cells (smc) and vimentin/calponin for myofibroblasts, following the estimation of their relative frequency and absolute volume by means of stereology. After one week diabetes led to a marked decrease in testosterone levels and an atrophy of about 35% in the VP. The relative frequency of smc and collagen fibers increased in the VP of diabetic rats but their absolute weight remained unchanged. Experimental diabetes promptly altered smc morphology which assumed at the ultrastructural level a shrunken appearance with the approximation of cytoplasmic dense bodies and also exhibited a decreased immunoreactivity to calponin. The conversion of stromal cells to a myofibroblast phenotype did not occur in alloxan-induced diabetes, as evaluated by double immunoreaction to calponin and vimentin. Insulin treatment maintained testosterone levels and preserved at least partly the cell morphology and collagen fiber organization of the prostate stroma in short-term diabetes. The apparent collagen increase observed by means of microscopic analysis in the stromal prostate compartment in the short term after diabetes is mainly associated with gland atrophy and does not involve the formation of new collagen fibers, the generation of myofibroblast-like cells or the acquisition of a secretory phenotype by stromal cells. 相似文献
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Octavio P. Luzardo Norberto Ruiz-Suárez Maira Almeida-González Luis Alberto Henríquez-Hernández Manuel Zumbado Luis D. Boada 《Analytical and bioanalytical chemistry》2013,405(29):9523-9536
Human breast milk represents the best choice for the nutrition of infants. However, in addition to containing beneficial nutrients and antibodies, it can also be considered the best indicator of infant exposure to contaminants. We developed a multi-residue method using a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure and capillary gas chromatography–triple quadrupole mass spectrometry for the determination of 57 persistent organic pollutants, including 23 organochlorine pesticides, 18 polychlorinated biphenyl (PCB) congeners, and 16 polycyclic aromatic hydrocarbons in human milk and colostrum samples. We have used primary secondary amine in the clean-up step as it gave a more efficient separation of the analytes from fat and superior removal of the co-extracted substances compared with gel permeation chromatography. No significant matrix effect was observed for the tested pollutants, and therefore matrix-matched calibration was not necessary. The average recoveries from spiked samples were in the range of 74.8–113.0 %. The precision was satisfactory, with relative standard deviations below 16 %, while values of 0.1–0.4 μg L?1 were established as the limit of quantification for all the target analytes (0.05 and 100 μg L?1). The method was successfully applied to the analysis of 18 human colostrum and 23 mature milk samples. All the samples tested were positive for at least nine different residues, with some samples containing up to 24 contaminants. Remarkably, the contaminants hexachlorobenzene, p,p’-DDE, PCB 138, PCB 180, phenanthrene, fluoranthene, and pyrene were present in 100 % of the colostrum and mature milk samples analyzed. 相似文献
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L. Acosta M. A. G. álvarez M. V. Andrés M. J. G. Borge M. Cortés J. M. Espino D. Galaviz J. Gómez-Camacho A. Maira I. Martel A. M. Moro I. Mukha F. Pérez-Bernal E. Reillo D. Rodríguez K. Rusek A. M. Sánchez-Benítez O. Tengblad 《The European Physical Journal A - Hadrons and Nuclei》2009,42(3):461-464
The angular distribution for 11Be + 120Sn quasielastic scattering at E lab = 32 MeV was measured at REX-ISOLDE, CERN. The interpretation of the data in terms of coupled-channel calculations suggests a strong coupling with the p -states lying in the continuum. 相似文献
24.
Maira D'Alessando Andrea Amadei Mauro Stener Massimiliano Aschi 《Journal of computational chemistry》2015,36(6):399-407
Essential Dynamics (ED) is a powerful tool for analyzing molecular dynamics (MD) simulations and it is widely adopted for conformational analysis of large molecular systems such as, for example, proteins and nucleic acids. In this study, we extend the use of ED to the study of clusters of arbitrary size constituted by weakly interacting particles, for example, atomic clusters and supramolecular systems. The key feature of the method we present is the identification of the relevant atomic‐molecular clusters to be analyzed by ED for extracting the information of interest. The application of this computational approach allows a straightforward and unbiased conformational study of the local microstructures in liquids, as emerged from semiclassical MD simulations. The good performance of the method is demonstrated by calculating typical observables of liquid water, that is, NMR, NEXAFS O1s, and IR spectra, known to be rather sensitive both to the presence and to the conformational features of hydrogen‐bonded clusters. © 2014 Wiley Periodicals, Inc. 相似文献
25.
Juan M. Coronado A. Javier Maira Arturo Martínez-Arias Jos Carlos Conesa Javier Soria 《Journal of photochemistry and photobiology. A, Chemistry》2002,150(1-3):213-221
EPR measurements reveal remarkable differences on the type of radicals produced after UV illumination of TiO2, CeO2 and 0.8% CeO2/TiO2 photocatalysts. Photoactivation of the TiO2 sample in vacuum results in the formation of Ti4+–O− species and a small amount of Ti3+ centers. In the presence of adsorbed oxygen, irradiation of this material also generates Ti4+–O3− radicals. In the case of the CeO2/TiO2 catalyst, the ceria component is present in a highly dispersed state, as indicated by XRD and UV–Vis diffuse reflectance spectra (DRS) results. Accordingly, the only type of Ce4+–O2− adducts generated on the CeO2/TiO2 sample are indicative of the presence of two-dimensional patches of ceria on the anatase surface. On the other hand, photoactivation of the CeO2/TiO2 sample in the presence of oxygen also leads to the formation of some Ti4+–O− and Ti3+ centers. In the case of the CeO2 sample, superoxide radicals are observed upon irradiation in vacuum and subsequent oxygen adsorption. Further irradiation of this material in the presence of oxygen increases the amount of Ce4+–O2− radicals and simultaneously generates new species, which are tentatively assigned to Ce4+–O2H radicals. Photocatalytic activity was tested for toluene oxidation, and the results obtained show that the photodegradation rate is slightly lower for CeO2/TiO2 than for the TiO2 sample. However, the selectivity towards benzaldehyde (6–13%) is comparable for both materials. In the case of CeO2, the photo-oxidation rate is an order of magnitude lower than for TiO2, although mineralization of toluene is almost complete. Photoactivity results are discussed in connection with the characteristics of the radicals observed. 相似文献
26.
da Silva Vitor Alves Sá de Lima Ana Layla Carvalho Codognoto Lucia Ferreira Tiago Luiz dos Santos Mauro Coelho Cerchiaro Giselle Valle Eliana Maira Agostini 《Transition Metal Chemistry》2021,46(4):291-297
Transition Metal Chemistry - Interactions occur between metal ions and organic molecules in the human body, and it is interesting to understand how this complexation happens and how stable it is in... 相似文献
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Maira R. Cerón Dr. Fang‐Fang Li Prof. Dr. Luis Echegoyen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(23):7410-7415
Based on the different oxidation potentials of endohedral fullerenes Sc3N@C80 Ih and D5h and Sc3N@C78, an efficient and useful method that avoids HPLC has been developed for their separation. Selective chemical oxidation of the Sc3N@D5h‐C80 isomer and Sc3N@C78 by using an acetylferrocenium salt [Fe(COCH3C5H4)Cp]+ followed by column chromatographic separation and reduction with CH3SNa resulted in the isolation of pure Sc3N@Ih‐C80, Sc3N@C78, and a mixture of Sc3N@D5h‐C80 and Sc3N@C68. 相似文献
29.
Fernando Fresno David Tudela A. Javier Maira Francisco Rivera Juan M. Coronado Javier Soria 《应用有机金属化学》2006,20(3):220-225
1H and 119Sn NMR results indicate that, when Ph3SnOH is dissolved in CD2Cl2, it dehydrates to (Ph3Sn)2O, only a small amount of Ph3SnOH remaining in equilibrium at room temperature. As a result, the reaction of TiCl4 with Ph3SnOH in CH2Cl2 proceeds via hydrolysis of the halide to precipitate amorphous TiO2 that contains adsorbed organotin species. Calcination of the amorphous precursor to 723 K yields nanoparticles of tin‐doped TiO2 photocatalysts, that contain anatase and rutile phases, and may also contain a segregated SnO2 phase. The reaction conditions that lead to the formation of a SnO2 phase have been studied and we have found that it is formed when the amorphous precipitate is not thoroughly washed with CH2Cl2 or when non‐recrystallized commercial Ph3SnOH is used as a starting material. The catalysts obtained have a high activity for the photooxidation of toluene in the gas phase. In particular, a material obtained from non‐recrystallized Ph3SnOH is particularly promising because the toluene photooxidation rate is more than twice as high as when using Degussa P25. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
30.
Lima Maira C. O. Pontedeiro Elizabeth M. Ramirez Mateus G. Favoreto Julia dos Santos Hélisson N. van Genuchten Martinus Th. Borghi Leonardo Couto Paulo Raoof Amir 《Transport in Porous Media》2022,143(1):103-125
Transport in Porous Media - Understanding the permeability distribution is an important basis for the design of hydraulic strengthened gas extraction. However, the existing methods can not directly... 相似文献