Rodrigo V. Rodrigues

Searching for molecular markers in head and neck squamous cell carcinomas (HNSCC) by statistical and bioinformatic analysis of larynx-derived SAGE libraries

BackgroundHead and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies in humans. The average 5-year survival rate is one of the lowest among aggressive cancers, showing no significant improvement in recent years. When detected early, HNSCC has a good prognosis, but most patients present metastatic disease at the time of diagnosis, which significantly reduces survival rate. Despite extensive research, no molecular markers are currently available for diagnostic or prognostic purposes.MethodsAiming to identify differentially-expressed genes involved in laryngeal squamous cell carcinoma (LSCC) development and progression, we generated individual Serial Analysis of Gene Expression (SAGE) libraries from a metastatic and non-metastatic larynx carcinoma, as well as from a normal larynx mucosa sample. Approximately 54,000 unique tags were sequenced in three libraries.ResultsStatistical data analysis identified a subset of 1,216 differentially expressed tags between tumor and normal libraries, and 894 differentially expressed tags between metastatic and non-metastatic carcinomas. Three genes displaying differential regulation, one down-regulated (KRT31) and two up-regulated (BST2, MFAP2), as well as one with a non-significant differential expression pattern (GNA15) in our SAGE data were selected for real-time polymerase chain reaction (PCR) in a set of HNSCC samples. Consistent with our statistical analysis, quantitative PCR confirmed the upregulation of BST2 and MFAP2 and the downregulation of KRT31 when samples of HNSCC were compared to tumor-free surgical margins. As expected, GNA15 presented a non-significant differential expression pattern when tumor samples were compared to normal tissues.ConclusionTo the best of our knowledge, this is the first study reporting SAGE data in head and neck squamous cell tumors. Statistical analysis was effective in identifying differentially expressed genes reportedly involved in cancer development. The differential expression of a subset of genes was confirmed in additional larynx carcinoma samples and in carcinomas from a distinct head and neck subsite. This result suggests the existence of potential common biomarkers for prognosis and targeted-therapy development in this heterogeneous type of tumor.

Luminescence investigation of Dy2O2S and Dy2O2SO4 obtained by thermal decomposition of sulfate hydrate

Abstract The yellow emitting dysprosium oxysulfide (Dy 2 O 2 S) and dysprosium oxysulfate (Dy 2 O 2 SO 4 ) compounds were prepared from the thermal decomposition of hydrated dysprosium sulphate. The materials were characterized by using thermogravimetry (TG/DTG), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies. The thermal stability temperatures at around 1151 and 1313 K were determined for the Dy 2 O 2 S and Dy 2 O 2 SO 4 materials, respectively. The photoluminescence properties of the dysprosium oxysulfide were investigated, showing narrow emission bands assigned to the 4 F 9/2 → 6 H J intraconfigurational transitions of the Dy 3+ ion. The yellow emission color of this phosphor suggests that the Dy 2 O 2 S is a promising material for applications in LEDs.

Influence of ethyl alcohol in the preparation, morphology and properties of compound DAS–Eu3+ and its thermal degradation products

In this study, two compounds presenting characteristics different from each other were produced from there action between hydrated Eu3+ sulfate and Ba2+ diphenylamine-4-sulfonate using, respectively, aqueous solution for producing the Eu(C12H10NSO3)3·7H2O (A) compound and water/ethyl alcohol (7:1) solution for the Eu(C12H10NSO3)3·5H2O (B) production. The presence of alcohol molecules in the solution will interfere in the structural arrangement of anionic surfactant DAS− (diphenylamine-4-sulfonate) around the metal ions Eu3+ allowing differentiation in the stoichiometric formulas, morphology, and thermal properties of these compounds and their derivatives. Thus, when treating both compounds under oxidizing atmosphere, we found different temperatures of the water loss and conversion of the intermediate pair oxydisulfate [Eu2O(SO4)2]/dioxysulfate [(Eu2O2SO4)]. However, the effect of water/surfactant/alcohol interactions in the metal ion structural arrangement becomes still more evident under reducing atmosphere. After this thermal treatment, significant changes were observed in the morphological characteristics and physical properties of the (Eu2O2S oxysulfide) in compound B with respect to compound A.