Time filter

Source Type

Budapest, Hungary

Lancastre J.J.H.,University of Lisbon | Falcao A.N.,University of Lisbon | Margaca F.M.A.,University of Lisbon | Ferreira L.M.,University of Lisbon | And 4 more authors.
Applied Surface Science | Year: 2015

Organic-inorganic materials have been the object of intense research due to their wide range of properties and therefore innumerous applications. We prepared organic-inorganic hybrid materials by direct energy deposition on a mixture of polydimethylsiloxane silanol terminated (33 wt% fixed content), tetraethylorthosilicate and a minor content of zirconium propoxide that varied from 1 to 5 wt% using gamma radiation from a Co-60 source. The samples, dried in air at room temperature, are bulk, flexible and transparent. Their nanostructure was investigated by small angle neutron scattering. It was found that the inorganic oxide network has fractal structure, which becomes denser as the zirconium propoxide content decreases. The results suggest that oxide nanosized regions grow from the OH terminal group of PDMS which are the condensation seeds. Their number and position remains unaltered with the variation of zirconium propoxide content that only affects their microstructure. A model is proposed for the nanostructure of the oxide network that develops in the irradiation processed hybrid materials. © 2015 Elsevier B.V. All rights reserved.

Kallai-Szabo N.,Semmelweis University | Luhn O.,ReSearch Pharmaceutical Services | Bernard J.,ReSearch Pharmaceutical Services | Kallai-Szabo B.,Gedeon Richter Ltd. | And 2 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2014

Layered and coated pellets were formulated to control the release of the diclofenac sodium selected as model drug. A highly water soluble isomalt inert pellet core material was used to osmotically modulate the drug release through the swellable polyvinyl acetate coating layer. Image analysis was applied to determine the shape parameters and the swelling behavior of the pellets. UV-spectroscopy and liquid chromatography with refractive index detection were applied to measure the concentration of the model drug and the core materials. Simultaneous dissolution of both the diclofenac sodium and isomalt was observed. Relationship was found between the dissolution profile of the drug and the core material which linear correlation was independent on the coating level. The latter enables the modulation of drug release beside the permeability control of the swelled coating polymer. © 2014 Elsevier B.V.

Boyle B.,Semmelweis University | Butz H.,Semmelweis University | Liko I.,Gedeon Richter Ltd. | Zalatnai A.,Semmelweis University | And 6 more authors.
Steroids | Year: 2010

Introduction: Glucocorticoid receptor (GR) is expressed in the normal human adrenal gland, however, no study has been performed to evaluate the separate expression of α- and β-isoforms (GRα and GRβ) in normal human adrenals and in adrenocortical adenomas. Experimental: GRα and GRβ mRNA expression was examined by quantitative real-time PCR in 31 adrenal tissues including 19 non-functioning adenomas (NFA), 6 cortisol-producing adenomas (CPA) and 6 normal adrenocortical tissues. In addition, the presence and cellular localization of GRα and GRβ proteins in adrenal tissues were studied by immunohistochemistry. Results: Compared to normal adrenocortical tissues, both GRα and GRβ mRNAs were significantly increased in CPA but not in NFA. Using anti-GRα antibody a strong nuclear staining was observed in NFA and CPA, and a less remarkable immunoreactivity was detected in some nuclei of normal adrenocortical cells.GRβ immunostaining was absent in normal adrenal tissues and NFA, while a strong cytoplasmic and nuclear immunoreaction was found in CPA. Conclusions: Altered expression of GRα and GRβ in CPA raises their possible role in the pathophysiology of these adrenal tumors, although further studies are needed to elucidate the potential significance of these findings. © 2010 Elsevier Inc. All rights reserved.

Tombol Z.,Semmelweis University | Eder K.,Hungarian Academy of Sciences | Kovacs A.,Semmelweis University | Szabo P.M.,Semmelweis University | And 10 more authors.
Modern Pathology | Year: 2010

MicroRNAs are involved in the pathogenesis of several tumors, however, there have been no data on microRNA expression in pheochromocytomas to date. The objective of our study was to perform microRNA expression profiling in sporadic and hereditary benign, and recurring adrenomedullary tumors. Furthermore, the applicability of formalin-fixed paraffin-embedded tissue samples for the analysis of microRNA expression in pheochromocytomas was examined. MicroRNA expression data of three matched frozen and formalin-fixed paraffin-embedded samples were correlated. A total of 21 formalin-fixed paraffin-embedded samples (sporadic benign, multiple endocrine neoplasia 2, von Hippel-Lindau disease, sporadic recurring) were subjected to microRNA expression profiling using microarrays. MicroRNAs with significant differences in expression were validated and sample sizes were extended including tumors from neurofibromatosis type 1 patients by real-time quantitative reverse-transcription PCR (n33). MicroRNA target prediction was carried out by TargetScan and MicroCosm Targets. Pathway analysis of targets was performed by Ingenuity Pathway Analysis and DIANA mirPath. Furthermore, microRNA expression profiles of a malignant pheochromocytoma and a pair of primary and recurrent tumors were studied by TaqMan Human MicroRNA Cards. MicroRNA expression correlated well between frozen and formalin-fixed paraffin-embedded samples (70-92%). Microarray analysis revealed 16 significantly differentially expressed microRNAs. Five of these were validated by real-time RT-PCR. miR-139-3p, miR-541 and miR-765 were significantly differentially expressed between sporadic benign and von Hippel-Lindau-related pheochromocytomas. Significantly higher expression of miR-885-5p and miR-1225-3p was found in multiple endocrine neoplasia type 2 and sporadic recurring pheochromocytomas, respectively. Pathway analysis revealed the possible involvement of Notch- and G-protein-coupled receptor signaling in tumor recurrence. MicroRNA expression profiles in the primary recurrent and recurring malignant comparisons have been similar. In conclusion, we have proved that formalin-fixed paraffin-embedded samples can be used for the analysis of microRNA expression in pheochromocytomas. MicroRNA expression patterns differ between various sporadic, hereditary and recurring tumors and miR-1225-3p may be useful for identifying recurring pheochromocytomas. © 2010 USCAP, Inc. All rights reserved.

Lancastre J.J.H.,University of Lisbon | Falcao A.N.,University of Lisbon | Margaca F.M.A.,University of Lisbon | Ferreira L.M.,University of Lisbon | And 4 more authors.
Radiation Physics and Chemistry | Year: 2015

Hybrid materials have been the object of intense research due to their potential for biomedical applications as well as in other fields. They are usually prepared by sol-gel but the method of gamma irradiation of the precursors is an alternative avoiding the addition of any other chemicals. The study of the hybrids prepared by this method has been progressing to understand the impact of different variables on the microstructure. In this work, the influence of the polymer's molecular weight on the microstructure of the materials is investigated. Hybrids were obtained from a mixture of polydimethylsiloxane (PDMS) silanol terminated, tetraethylorthosilicate (TEOS) and zirconium propoxide (PrZr) in the wt% composition 20PDMS-73TEOS-7PrZr varying only the PDMS molecular weight. The obtained materials are homogeneous, transparent and flexible and their microstructure was analysed by Scanning Electron Microscopy (SEM) and Small-Angle Neutron Scattering (SANS). It was found that different microstructures were obtained, depending on the polymer molecular weight. © 2014 Elsevier Ltd.

Discover hidden collaborations