RESUMO
Radiochromic and radiographic films are widely used for radiation dosimetry due to the advantage of high spatial resolution and two-dimensional dose measurement. Different types of scanners, including various models of flatbed scanners, have been used as part of the dosimetry readout procedure. This paper focuses on the characterization of the EBT2 film response in combination with a Microtek ScanMaker 9800XL scanner and the subsequent use in the dosimetric verification of a 3D conformal radiotherapy treatment. The film reproducibility and scanner uniformity of the Microtek ScanMaker 9800XL was studied. A three-field 3D conformal radiotherapy treatment was planned on an anthropomorphic phantom and EBT2 film measurements were carried out to verify the treatment. The interfilm reproducibility was found to be 0.25%. Over a period of three months, the films darkened by 1%. The scanner reproducibility was ± 2% and a nonuniformity was ±1.9% along the direction perpendicular to the scan direction. EBT2 measurements showed an underdose of 6.2% at high-dose region compared to TPS predicted dose. This may be due to the inability of the treatment planning system to predict the correct dose distribution in the presence of tissue inhomogeneities and the uncertainty of the scanner reproducibility and uniformity. The use of EBT2 film in conjunction with the axial CT image of the anthropomorphic phantom allows the evaluation of the anatomical location of dose discrepancies between the EBT2 measured dose distribution and TPS predicted dose distribution.
Assuntos
Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia Conformacional/normas , Filme para Raios X , Calibragem , Humanos , Imageamento Tridimensional , Imagens de Fantasmas , Controle de Qualidade , Radiometria/instrumentação , Radiometria/normas , Dosagem Radioterapêutica , Reprodutibilidade dos TestesRESUMO
Matrix metalloproteinases (MMPs) are known to play an important role in photoaging by mediating the degradation of extracellular matrix proteins. To develop a new anti-aging agent for cosmetics from natural products, Melothria heterophylla (Lour.) Cogn. was selected for its antioxidant activity and inhibitory effect on expression of MMP-1 in UVA-irradiated human skin fibroblasts. Two compounds (compounds 1 and 2 ) were isolated from an ethyl acetate soluble fraction of the ethanolic extracts; they were identified as 1,2,4,6-tetra-O-galloyl-beta-(D)-glucopyranose (1) and 3,4,5-trihydroxybenzoic acid (2). These compounds were found to scavenge radicals and reactive oxygen species (ROS) and were measured to have SC50 values of 3.9 microM and 13.3 microM against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and values of 4.3 microM and 4.0 microM against superoxide radicals in the xanthine/xanthine oxidase system, respectively. Compounds 1 and 2 showed a dose-dependent inhibitory effect on the expression and activity of MMP-1 in UVA-induced human skin fibroblasts, but no inhibition of MMP-1 mRNA expression. Therefore, we concluded that compounds 1 and 2 significantly inhibited MMP-1 expression at the protein level. Also, these compounds were determined to have a potent antioxidant activity. From these results, we suggest that these compounds might be useful as a new anti-aging agent for photodamaged skin, but the in vitro findings must be verified in in vivo studies.
Assuntos
Antioxidantes/farmacologia , Cucurbitaceae/química , Ácido Gálico/farmacologia , Glucose/análogos & derivados , Inibidores de Metaloproteinases de Matriz , Pele/efeitos dos fármacos , Antioxidantes/química , Antioxidantes/isolamento & purificação , Compostos de Bifenilo/química , Ensaio de Imunoadsorção Enzimática , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Fibroblastos/efeitos da radiação , Ácido Gálico/química , Ácido Gálico/isolamento & purificação , Glucose/química , Glucose/farmacologia , Humanos , Hidrazinas/química , Metaloproteinase 1 da Matriz/biossíntese , Metaloproteinase 1 da Matriz/genética , Ressonância Magnética Nuclear Biomolecular , Picratos , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Raízes de Plantas/química , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Pele/enzimologia , Pele/efeitos da radiação , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Ultravioleta , Superóxidos/químicaRESUMO
In this study of 132 infertile couples, findings with hysterosalpingography (HSG) were compared with those observed at subsequent culdoscopy or laparoscopy. Both procedures correctly revealed normal tubes in 29% of the subjects and identical abnormalities in 24%. A complete agreement between the two procedures was thus observed in 53% of women. Hysterosalpingography showed 5% false positive and 14% false negative findings. In the remaining cases the type of anomaly revealed by HSG was different from that found at laparoscopy. Peritubal adhesion was the pathologic process most commonly missed by HSG and diagnosed subsequently by endoscopy. Pelvic endoscopy also revealed endometriosis and other pelvic disease in a high proportion of women, whereas HSG exclusively detected all intrauterine lesions. Similar pregnancy rates resulted when HSG and endoscopy revealed normal organs. The significance of these findings is discussed.