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Agora exibindo 1 - 10 de 28
  • Artigo IPEN-doc 24768
    Radiolabeled GX1 peptide for tumor angiogenesis imaging
    2018 - OLIVEIRA, ERICA A. de; FAINTUCH, BLUMA L.; SEO, DANIELE; BARBEZAN, ANGELICA B.; FUNARI, ANA; TARGINO, ROSELAINE C.; MORO, ANA M.
    Early and accurate detection of primary or metastatic tumors is of great value in staging, treatment management, and prognosis. Tumor angiogenesis plays an essential role in the growth, invasion, and metastatic spread of solid cancers, and so, is a promising approach for tumor imaging. The GX1 (CGNSNPKSC) peptide was identified by phage display library and has been investigated as a marker for human cancers. This study aims to evaluate the 99mTc-HYNIC-PEG4-c (GX1) as a biomarker for tumor imaging. Our results showed that GX1 specifically binds to tumor cells in vitro. SKMEL28 and MDA-MB231 cells achieved total binding peak at 60 min of incubation. For B16F10 and MKN45 cells, the total and specific binding were similar during all time points, while A549 cell line showed rapid cellular total uptake of the tracer at 30 min of incubation. Biodistribution showed low non-specific uptakes and rapid renal excretion. Melanoma tumors showed enhanced GX1 uptake in animal model at 60 min, and it was significantly blocked by cold peptide. The radiotracer showed tumor specificity, especially in melanomas that are highly vascularized tumors. In this sense, it should be considered in future studies, aiming to evaluate degree of angiogenesis, progression, and invasion of tumors.
  • Tese IPEN-doc 23011
    Desenvolvimento de biomarcador específico de células beta pancreáticas (incretina radiomarcada) para imagem da massa beta funcional em diabéticos e obesos: estudo em modelo animal
    2017 - SEO, DANIELE
    O aumento nos casos de obesidade em todo o mundo tem gerado grande preocupação e estimulado pesquisas na prevenção e tratamento dessa condição patológica. A combinação de diabetes tipo 2 ou resistência insulínica com obesidade agrava o potencial evolutivo da enfermidade. Mesmo pacientes submetidos com sucesso à cirurgia bariátrica ou metabólica, podem não se curar do diabetes, pois a melhora das taxas circulantes de glicose e insulina nem sempre corresponde à recuperação da massa beta pancreática. Até o momento, não há consenso sobre como medir a massa de células beta in vivo. As ferramentas disponíveis padecem de baixa sensibilidade e especificidade, muitas vezes revelando-se também complexas e dispendiosas. Incretinas radiomarcadas ,como os análogos do peptídeo glucagon-like-peptide-1 / GLP-1, têm-se revelado promissoras para avaliação de células beta pancreáticas, em diabetes e insulinoma. O objetivo do presente trabalho foi o desenvolvimento de dois conjugados de análogo de incretina GLP-1, marcados com tecnécio-99m, a fim de propor um método não invasivo de imagem, para monitoração da massa de células beta pancreáticas, em organismos afetados por obesidade. O estudo foi conduzido em diferentes modelos animais, incluindo obesidade induzida por dieta hiperlipídica, estado pós-obesidade em que o distúrbio inicialmente gerado foi parcialmente corrigido, e como controle, diabetes induzido com aloxana. Nos resultados, os radiotraçadores alcançaram um rendimento radioquímico superior a 97%. O melhor radiomarcador, dentre os dois análogos ensaiados, foi o 99mTc-HYNIC-βAla-Exendin-4. Animais com obesidade induzida por dieta revelaram captação reduzida nas células beta pancreáticas. A restrição dietética (estado pós-obesidade) não se seguiu de recuperação completa, embora notável melhora de glicemia haja sido observada. Estudos futuros são indicados em modelos de obesidade, diabetes tipo 2 e tratamento dietético, incluindo cirurgia bariátrica e metabólica.
  • Artigo IPEN-doc 23935
    Pancreas and liver uptake of new radiolabeled incretins (GLP-1 and Exendin-4) in models of diet-induced and diet-restricted obesity
    2017 - SEO, DANIELE; FAINTUCH, BLUMA L.; OLIVEIRA, ERICA A. de; FAINTUCH, JOEL
    Introduction: Radiolabeled GLP-1 and its analog Exendin-4, have been employed in diabetes and insulinoma. No protocol in conventional Diet-Induced Obesity (DIO), and Diet-Restricted Obesity (DRO), has been identified. Aiming to assess pancreatic beta cell uptake in DIO and DRO, a protocol was designed. Methods: GLP-1-βAla-HYNIC and HYNIC-βAla-Exendin-4 were labeled with technetium-99m. Four Swiss mouse models were adopted: Controls (C), Alloxan Diabetes Controls (ADC), DIO and DRO. Biodistribution and ex-vivo planar imaging were documented. Results: Radiolabeling yield was in the range of 97% and both agents were hydrophilic. Fasting Blood Glucose (FBG) was 79.2 ± 8.2 mg/dl in C, 590.4 ± 23.3 mg/dl in ADC, 234.3 ± 66.7 mg/dl in DIO, and 96.6 ± 9.3 in DRO (p = 0.010). Biodistribution confirmed predominantly urinary excretion. DIO mice exhibited depressed uptake in liver and pancreas, for both radiomarkers, in the range of ADC. DRO only partially restored such values. 99mTc-HYNIC-βAla-Exendin-4 demonstrated better results than GLP-1-βAla-HYNIC-99mTc. Conclusions: 1) Diet-induced obesity remarkably depressed beta cell uptake; 2) Restriction of obesity failed to normalize uptake, despite robust improvement of FBG; 3) HYNIC-βAla-Exendin-4 was the most useful marker; 4) Further studies are recommended in obesity and dieting, including bariatric surgery.
  • Artigo IPEN-doc 23933
    Evaluation of the influence of the conjugation site of the chelator agent HYNIC to GLP1 antagonist radiotracer for insulinoma diagnosis
    2017 - FAINTUCH, BLUMA L.; SEO, DANIELE; OLIVEIRA, ERICA A. de; TARGINO, ROSELAINE C.; MORO, ANA M.
    Background and Objective: Radiotracer diagnosis of insulinoma, can be done using somatostatin or glucagon-like peptide 1 (GLP-1). Performance of GLP-1 antagonists tends to be better than of agonists. Methods: We investigated the uptake of the antagonist exendin (9-39), radiolabeled with technetium-99m. Two different sites of the biomolecule were selected for chelator attachment. Results: HYNIC-beta Ala chelator attached to serine (C-terminus) of exendin, was associated with higher tumor uptake than to aspartate (N-terminus). Conclusion: The chelator position in the biomolecule influenced receptor uptake.
  • Resumo IPEN-doc 14330
    Essential and toxic elements determination in brazilian cultivated mussel Perna perna
    2009 - CATHARINO, MARILIA G.M.; SEO, DANIELE; VASCONCELLOS, MARINA B.A.; SAIKI, MITIKO; MOREIRA, EDSON G.; SOUSA, EDUINETTY C.P.M.; PEREIRA, CAMILO D.S.
  • Resumo IPEN-doc 17612
    Vanadium biomonitoring using Pernaa perna mussels transplanted in North Coast of the state of São Paulo, Brazil
    2011 - SEO, DANIELE; VASCONCELLOS, MARINA B.A.; CATHARINO, MARILIA G.M.; MOREIRA, EDSON G.; PEREIRA, CAMILO D.S.; SOUSA, EDUINETTY C.P.M. de; SAIKI, MITIKO
  • Resumo IPEN-doc 17613
    Passive biomonitoring study for trace elements in oysters Crassostrea brasiliana (LAMARCK, 1819: mollusca bibalvia) in São Paulo state coastal sites, Brazil (25o00'-23o56'S,47o25'-45o19'W)
    2011 - CATHARINO, MARILIA G.M.; VASCONCELLOS, MARINA B.A.; KIRSCHBAUM, ALINE A.; GASPARRO, MARCIA R.; SOUSA, EDUINETTY C.P.M. de; MINEI, CLAUDIA C.; MOREIRA, EDSON G.; SEO, DANIELE
  • Resumo IPEN-doc 15734
    Avaliacao de Mg e Mn em mexilhoes Perna perna transplantados no litoral norte paulista
    2010 - SEO, D.; VASCONCELLOS, M.B.A.; SAIKI, M.; CATHARINO, M.G.M.; MOREIRA, E.G.; SOUSA, E.C.P.M. de; PEREIRA, C.D.S.