RESUMEN
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.
Asunto(s)
Planificación de la Radioterapia Asistida por Computador/normas , Radioterapia Conformacional/normas , Película para Rayos X , Calibración , Humanos , Imagenología Tridimensional , Fantasmas de Imagen , Control de Calidad , Radiometría/instrumentación , Radiometría/normas , Dosificación Radioterapéutica , Reproducibilidad de los ResultadosRESUMEN
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.
Asunto(s)
Antioxidantes/farmacología , Cucurbitaceae/química , Ácido Gálico/farmacología , Glucosa/análogos & derivados , Inhibidores de la Metaloproteinasa de la Matriz , Piel/efectos de los fármacos , Antioxidantes/química , Antioxidantes/aislamiento & purificación , Compuestos de Bifenilo/química , Ensayo de Inmunoadsorción Enzimática , Fibroblastos/efectos de los fármacos , Fibroblastos/enzimología , Fibroblastos/efectos de la radiación , Ácido Gálico/química , Ácido Gálico/aislamiento & purificación , Glucosa/química , Glucosa/farmacología , Humanos , Hidrazinas/química , Metaloproteinasa 1 de la Matriz/biosíntesis , Metaloproteinasa 1 de la Matriz/genética , Resonancia Magnética Nuclear Biomolecular , Picratos , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/farmacología , Raíces de Plantas/química , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Piel/enzimología , Piel/efectos de la radiación , Espectrometría de Masa Bombardeada por Átomos Veloces , Espectrofotometría Ultravioleta , Superóxidos/químicaRESUMEN
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.