Optimization of an amperometric biosensor for the detection of hepatitis C virus using fractional factorial designs

Fractional factorial design and factorial with center point design were applied to the development of an amperometric biosensor for the detection of the hepatitis C virus. Biomolecules were immobilized by adsorption on graphite electrodes modified with siloxane-poly(propyleneoxide) hybrid matrix prepared using the sol-gel method. Several parameters were optimized, such as the streptavidin concentration at 0.01 mg mL(-1) and 1.0% bovine serum albumin, the incubation time of the electrodes in the complementary DNA solution for 30 minutes and a 1: 1500 dilution of the avidin-peroxidase conjugate, among others. The application of chemometric studies has been efficient, since the best conditions have been established with a restricted number of experiments, indicating the influence of different factors on the system.

Characterization of the cellular component of polymorphous low-grade adenocarcinoma by immunohistochemistry and electron microscopy

In order to characterize the cellular component of the polymorphous low-grade adenocarcinoma (PLGA) of the salivary gland, a morphological and immunohistochemical study was carried out. Thirty cases of PLGA were studied by light microscopy and immunohistochemistry and five cases by transmission electron microscopy (TEM). The expression of cytokeratins (CKs) 7,8,10,13,14,18,19, vimentin and muscle-specific actin (MSA) was investigated through the streptavidin-biotin method. The majority of tumor cells stained for vimentin, CKs 8,18 and 7. CK 14 was positive in most cells of the papillary and trabecular sub-types. Although the expression of CKs 8,18 and 14 varied among the tumors sub-types, a straight relationship between each histologic pattern and the CK expression could not be delineated. MSA was reactive in only three tumors while CKs 10 and 13 were not detected in any tumor studied. The absence of MSA and the expression of CKs 8,18 and 7, in most of the tumor cells, lead to the hypothesis that myoepithelial cells are not the major cellular component of the PLGA. TEM revealed cells exhibiting microvilli and variable amounts of secretory granules, some of them suggesting an excretory activity. The presence of CKs 8, 18 and 7, added to the secretory granules, indicates that PLGA originates from cells located at the acinar-intercalated duct junction. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

Estudo imunoistoquímico da expressão de actina, vimentina, calponina e caldesmona no adenoma pleomórfico, adenocarcinoma polimorfo de baixo grau de malignidade e carcinoma adenóide cístico de glândulas salivares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relação da ciclooxigenase-2 com VEGF e a caspase-3 nas neoplasias mamárias de cadelas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Expressão imuno-histoquímica de metaloproteinase de matriz-9 (MMP-9) e de inibidor tecidual de metaloproteinase-1 (TIMP-1) em neoplasias de glândulas salivares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da membrana amniótica homógena associada ao laser arseneto de gálio-alumínio (λ=660) na reparação de mucosite oral em ratos tratados com 5-fluoruracila: análise histológica e imunohistoquímica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento e aperfeiçoamento de protocolos de conjugação de nanomarcadores luminescentes com sistemas biológicos para aplicação em imunoensaios

Pós-graduação em Química - IBILCE

Desenvolvimento de um biosensor amperométrico para a detecção do vírus da Hepatite C

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo anátomo-clínico do linfonodo sentinela no câncer de mama

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

Caracterização do infiltrado inflamatório e avaliação dos marcadores de prognóstico Ki-67, p53, receptor de estrógeno e progesterona no tumor mamário maligno de cadelas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Construção de genossensor amperométrico para diagnóstico da hepatite C baseado em monocamadas auto montadas e detecção não marcada

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de dispositivos para diagnósticos e genotipagem de Hepatite C

Pós-graduação em Química - IQ

Utilização da técnica de imuno-histoquímica para confirmar casos de pitiose cutânea equina diagnosticados por meio de caracterização clínica e avaliação histopatológica

Twelve granulomatous lesions in the thoracic and pelvic limbs of horses from pantaneira breed were evaluated. It was performed suggestive diagnostic of cutaneous pythiosis according to the clinic characteristics of the lesions and histopathological exams using hematoxylin and eosin (HE) and Grocott's methenamine silver (GMS) stains. The confirmation of the diagnoses was performed by the labelled streptavidin biotin (LSAB) method (immunohistochemistry). Extensive focal pyogranulomatous dermatitis associated with pseudo hyphae characteristic of Pythium insidiosum (subcutaneous pythiosis) was the histopathological diagnosis for all 12 horses used in this study. It was confirmed in 100% of the cases by the positive result to Pythium insidiosum in the immunohistochemistry exam, characterized by the visualization of branched and septated structures. It was observed 100% of parity between the techniques. We can conclude that clinical characterization of the granulomatous lesions with pythiosis aspects in horses associated with histopathology suggestive of equine pythiosis constitute a reliable method of diagnostic that can be confirmed by immunohistochemistry technique.

Quantificação do fator de crescimento semelhante a insulina I (IGF-I) em plasma bovino por ELISA

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Holocarboxylase Synthetase-dependent Biotinylation of Histone H4

Holocarboxylase synthetase (HCS) catalyzes the binding of biotin to lysine (K) residues in histones H3 and H4. Histone biotinylation marks play important roles in the repression of genes and retrotransposons. Preliminary studies suggested that K16 in histone H4 is a target for biotinylation by HCS. Here we demonstrated that H4K16bio is overrepresented in repeat regions {pericentromeric alpha satellite repeats; long terminal repeats (LTR)} compared with euchromatin promoters. H4K16bio was also enriched in the repressed interleukin-2 gene promoter. The enrichment at LTR22 and promoter 1 of the sodium-dependent multivitamin transporter (SMVT) depended on biotin supply; and was significantly lower in fibroblasts from an HCS-deficient patient compared with an HCS wild-type control. We conclude that H4K16bio is a real phenomenon and plays a role in the transcriptional repression of repeats and genes. HCS catalyzes the covalent binding of biotin to carboxylases, in addition to its role as a histone biotinyl ligase. HCS null individuals are not viable whereas HCS deficiency is linked to developmental delays and phenotypes such as short life span and low stress resistance. Here, we developed a 96-well plate assay for high-throughput analysis of HCS based on the detection of biotinylated p67 using IRDye-streptavidin and infrared spectroscopy. We demonstrated that the catalytic activity of rHCS depends on temperature and time, and proposed optimal substrate and enzyme concentrations to ensure ideal measurement of rHCS activity and its kinetics. Additionally, we demonstrated that this assay is sensitive enough to detect biotinylation of p67 by endogenous HCS from Jurkat lymphoid cells.