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1.
Eur Radiol ; 26(5): 1466-73, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26310582

RESUMO

OBJECTIVES: To compare bilateral diffusion-weighted MR imaging (DWI) at 3 T and 7 T in the same breast tumour patients. METHODS: Twenty-eight patients were included in this IRB-approved study (mean age 56 ± 16 years). Before contrast-enhanced imaging, bilateral DWI with b = 0 and 850 s/mm(2) was performed in 2:56 min (3 T) and 3:48 min (7 T), using readout-segmented echo planar imaging (rs-EPI) with a 1.4 × 1.4 mm(2) (3 T)/0.9 × 0.9 mm(2) (7 T) in-plane resolution. Apparent diffusion coefficients (ADC), signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were assessed. RESULTS: Twenty-eight lesions were detected (18 malignant, 10 benign). CNR and SNR were comparable at both field strengths (p > 0.3). Mean ADC values at 7 T were 4-22% lower than at 3 T (p ≤ 0.03). An ADC threshold of 1.275 × 10(-3) mm(2)/s resulted in a diagnostic specificity of 90% at both field strengths. The sensitivity was 94% and 100% at 3 T and 7 T, respectively. CONCLUSION: 7-T DWI of the breast can be performed with 2.4-fold higher spatial resolution than 3 T, without significant differences in SNR if compared to 3 T. KEY POINTS: • 7 T provides a 2.4-fold higher resolution in breast DWI than 3 T • 7 T DWI has a high diagnostic accuracy comparable to that at 3 T • At 7 T malignant lesions had 22 % lower ADC than at 3 T (p < 0.001).


Assuntos
Neoplasias da Mama/patologia , Mastite/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Imagem Ecoplanar/métodos , Feminino , Fibroadenoma/patologia , Humanos , Aumento da Imagem/métodos , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Carga Tumoral , Adulto Jovem
2.
Exp Cell Res ; 271(2): 296-304, 2001 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-11716542

RESUMO

Yeast cells growing on solid media organize themselves into multicellular structures, colonies, exhibiting patterns specific for particular yeast strains. With the aim of identifying genes involved in regulations of the colony formation, we applied a new approach enabling the extensive screening of Saccharomyces cerevisiae genes, the expression of which is changed during colony development. We used the library of S. cerevisiae DNA fragments inserted in front of the lacZ gene lacking its own promoter. Colonies of transformants with a blue/white patterned morphotype, implying that the expression of the lacZ gene from the inserted yeast promoter is switched on and off during the colony formation, were isolated. We identified several genes with variable expression during colony morphogenesis, including CCR4, PAM1, MEP3, ADE5,7 and CAT2. S. cerevisiae strain deleted in the CCR4 gene forms colonies with less organized morphology when compared with the isogenic parental strain. The synchronization of the expression patterns of some of the isolated genes in neighboring colonies was observed.


Assuntos
Proteínas de Transporte de Cátions , Diferenciação Celular/genética , Divisão Celular/genética , Regulação da Expressão Gênica/genética , Ribonucleases , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Carboxiliases/genética , Proteínas de Transporte/genética , Catalase/genética , Mapeamento Cromossômico/métodos , Meios de Cultura/farmacologia , Proteínas Fúngicas/genética , Deleção de Genes , Genes Reporter/genética , Biblioteca Genômica , Oxigenases de Função Mista/genética , Complexos Multienzimáticos/genética , Mutação/genética , Peptídeo Sintases/genética , Plasmídeos/genética , Regiões Promotoras Genéticas/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/genética , Transcrição Gênica/genética , Transformação Genética/genética , beta-Galactosidase/genética
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