RESUMEN
As an iron oxyhydroxide, nanosized ferrihydrite (Fh) is important in Earth science, biology, and industrial applications. However, its basic structure and origin of its magnetism have long been debated. We integrate synchrotron-based techniques to explore the chemical structures of 2-line ferrihydrite and to determine the origin of its magnetism during hydrothermal aging in air. Our results demonstrate that both the magnetism and X-ray magnetic circular dichroism (XMCD) signal of 2-line ferrihydrite are enhanced with aging time, and that XMCD spectral patterns resemble that of maghemite (γ-Fe2O3) rather than magnetite (Fe3O4). Fe L-edge and K-edge X-ray absorption spectroscopy (XAS) further indicate formation of both maghemite and hematite (α-Fe2O3) with increasing concentrations with longer hydrothermal aging time. Thus, magnetic enhancement with longer hydrothermal aging time is attributed to increasing maghemite concentration instead of a magnetically ordered ferrihydrite as previously reported. Moreover, L-edge and K-edge XAS spectra with different probing depths yield different ratios of these Fe oxides, which suggest the formation of a core (ferrihydrite-rich)-shell (with a mixture of both allotropes; α-Fe2O3 and γ-Fe2O3) structure during hydrothermal aging. Our results provide insights into the chemical evolution of 2-line ferrihydrite that reveal unambiguously the origin of its magnetism.
Asunto(s)
Compuestos Férricos/química , Suspensiones , Magnetismo , Espectroscopía de Absorción de Rayos X , Rayos XRESUMEN
AIM: To investigate computed tomography (CT) and magnetic resonance imaging (MRI) manifestations of rectal gastrointestinal stromal tumors (GISTs) in order to enhance the recognition of these rare tumors. METHODS: Fourteen patients with pathologically proven rectal GISTs were retrospectively reviewed. Patient histories were retrospectively reviewed for patient age, gender, presenting symptoms, endoscopic investigations, operation notes and pathologic slides. All tumors were evaluated for CD117, CD34 expression, and the tumors were stratified according to current criteria of the National Institutes of Health (NIH). In all cases the first pre-operation imaging findings (CT and MRI, n = 3; MRI only, n = 8; CT only, n = 3) were analyzed by two experienced radiologists by consensus, which include: tumor size, shape, CT density (hypodense, isodense and hyperdense), MRI signal intensity (hypointense, isointense and hyperintense), epicenter (intraluminal or extraluminal), margin (well-defined or ill-defined), internal component (presence of calcifications, necrosis, hemorrhage or ulceration), pattern and degree of enhancement, invasion into adjacent structures. After review of the radiologic studies, clinical and pathological findings were correlated with radiological findings. RESULTS: The patients, 13 men and 1 woman, were aged 31-62 years (mean = 51.5 ± 10.7 years). The most common initial presentation was hematochezia (n = 6). The mean tumor diameter was 5.68 ± 2.64 cm (range 1.5-11.2 cm). Eight lesions were round or oval, and 6 lesions were irregular. Eleven lesions were well-defined and 3 had ill-defined margins. Ten tumors were extraluminal and 4 were intraluminal. The density and MR signal intensity of the solid component of the lesions were similar to that of muscle on unenhanced CT (n = 6) and T1-weighted images (n = 11), and hyperintense on T2-weighted MR images. Calcification was detected in 2 tumors. Following intravenous injection of contrast media, 3 lesions had mild enhancement and 11 lesions had moderate enhancement. Enhancement was homogenous in 3 lesions and heterogeneous in 11. In 1 of 11 patients who underwent both CT and MRI, the tumor was homogenous on CT scan and heterogeneous on MRI. Eight patients were classified as high risk according to the modified recurrent risk classification system of NIH. CONCLUSION: Rectal GISTs usually manifest as large, well-circumscribed, exophytic masses with moderate and heterogeneous enhancement on CT and MRI. The invasion of adjacent organs, bowel obstruction and local adenopathy are uncommon.
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Tumores del Estroma Gastrointestinal/diagnóstico , Imagen por Resonancia Magnética , Neoplasias del Recto/diagnóstico , Tomografía Computarizada por Rayos X , Adulto , Antígenos CD34/análisis , Biomarcadores de Tumor/análisis , Biopsia , Colonoscopía , Endosonografía , Femenino , Tumores del Estroma Gastrointestinal/química , Tumores del Estroma Gastrointestinal/diagnóstico por imagen , Tumores del Estroma Gastrointestinal/patología , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Valor Predictivo de las Pruebas , Pronóstico , Proteínas Proto-Oncogénicas c-kit/análisis , Neoplasias del Recto/química , Neoplasias del Recto/diagnóstico por imagen , Neoplasias del Recto/patología , Estudios Retrospectivos , Carga TumoralRESUMEN
PURPOSE: To investigate the feasibility and efficacy of curettage with hysteroscopy followed by megestrol acetate (MA) for well-differentiated endometrioid carcinoma (EC) confined to the endometrium and for atypical hyperplasia (AH) in young women. PATIENTS AND METHODS: Fourteen patients with EC and 12 patients with AH were prospectively enrolled in this study. All of the patients received at least 12 weeks of oral MA (160 mg/day) following thorough curettage with hysteroscopy. The response was assessed histologically every 12 weeks. The primary endpoint was the complete response rate. Adverse events, pregnancy rates and recurrence rates were secondary end points. RESULTS: Twenty-one (80.8 %) patients responded to treatment. The median time to response was 12 weeks. After a median follow-up of 32 months, 6 patients had recurrences. Significantly, more patients with infertility or PCOS experienced recurrence (P = 0.040, P = 0.015). Eight patients attempted to conceive after complete response; two spontaneous conceptions and one normal delivery were achieved. No disease-related or treatment-related deaths were observed. CONCLUSIONS: Fertility-sparing treatment with MA following entirely hysteroscopic curettage is effective, demonstrating the least toxicity for rigorously selected young women with well-differentiated EC confined to the endometrium or with AH; however, close follow-up is required for the potential consequences of improper patient selection and a substantial rate of recurrence.
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Antineoplásicos Hormonales/uso terapéutico , Carcinoma Endometrioide/terapia , Legrado , Neoplasias Endometriales/terapia , Endometrio/patología , Preservación de la Fertilidad , Acetato de Megestrol/uso terapéutico , Recurrencia Local de Neoplasia/terapia , Adolescente , Adulto , Carcinoma Endometrioide/patología , Terapia Combinada , Neoplasias Endometriales/patología , Estudios de Factibilidad , Femenino , Humanos , Hiperplasia/patología , Hiperplasia/terapia , Histeroscopía , Embarazo , Índice de Embarazo , Estudios Prospectivos , Adulto JovenRESUMEN
OBJECTIVE: To evaluate the diagnostic value of full-field digital mammography for breast cancer. METHODS: The clinical data and mammograms of 230 patients with breast diseases between January 2008 and July 2008 were collected and reviewed. Craniocaudal (CC) and mediolateral oblique (MLO) view mammograms were performed in all patients before surgery. Three experienced radiologists in breast imaging assessment analyzed and classified all the mammograms according to breast imaging reporting and data system (BI-RADS). The sensitivity, specificity and accuracy were evaluated according to their pathological diagnosis. The reasons resulting in false-negative and false-positive diagnosis were also analyzed. RESULTS: Of the 238 samples, 130 had a malignant breast tumors and 108 cases of benign breast lesions. One hundred and nine of the 130 malignant breast tumors were invasive ductal carcinoma. Fifty-seven of the 108 benign breast lesions were breast adenosis. Masses or masses with microcalcification were the most frequently seen signs of the malignant tumors, accounting for 40.8% and 20.8%, respectively. The sensitivity, specificity and accuracy of FFDM in detecting breast carcinoma were 90.8%, 87.0% and 89.1%, respectively. The false-negative signs including negative X-ray finding (5 cases) and focal asymmetric densities (4 cases). The false-positive signs were masses with spiculate, indistinctive or lobulated margin leading to misdiagnosing the lesions as malignant tumors. CONCLUSION: Full-field digital mammography (FFDM) is helpful in detection of breast cancers in women, with a higher sensitivity, specificity and accuracy, and has an important clinical application value.
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Neoplasias de la Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico , Enfermedad Fibroquística de la Mama/diagnóstico , Mamografía/métodos , Adulto , Anciano , Anciano de 80 o más Años , Enfermedades de la Mama/diagnóstico , Enfermedades de la Mama/diagnóstico por imagen , Neoplasias de la Mama/diagnóstico por imagen , Calcinosis/diagnóstico , Calcinosis/diagnóstico por imagen , Carcinoma Ductal de Mama/diagnóstico por imagen , Errores Diagnósticos , Femenino , Enfermedad Fibroquística de la Mama/diagnóstico por imagen , Humanos , Persona de Mediana Edad , Interpretación de Imagen Radiográfica Asistida por Computador , Estudios RetrospectivosRESUMEN
AIM: To explore the diffusion gradient b-factor that optimizes both apparent diffusion coefficient (ADC) measurement and contrast-to-noise (CNR) for assessing tumor response to transarterial chemoembolization (TACE) in a rabbit model. METHODS: Twelve New Zealand white rabbits bearing VX2 tumors in the liver were treated with TACE. Diffusion-weighted imaging (DWI) with various b values was performed using the same protocol before and 3 d after treatment with TACE. ADC values and CNR of each tumor pre- and post-treatment with different b factors were analyzed. Correlation between ADC values and extent of necrosis in histological specimens was analyzed by a Pearson's correlation test. RESULTS: The quality of diffusion-weighted images diminished as the b value increased. A substantial decrease in the mean lesion-to-liver CNR was observed on both pre- and post-treatment DW images, the largest difference in CNR pre- and post-treatment was manifested at a b value of 1000 s/mm(2) (P = 0.036 ). The effect of therapy on diffusion early after treatment was shown by a significant increase in ADCs (P = 0.007), especially with large b factors (>= 600 s/mm(2)). The mean percentage of necrotic cells present within the tumor was 76.3%-97.5%. A significant positive correlation was found between ADC values and the extent of necrosis with all b values except for b200, a higher relative coefficient between ADC values and percentage of necrosis was found on DWI with b1000 and b2000 (P = 0.002 and 0.006, respectively). CONCLUSION: An increasing b value of up to 600 s/mm(2) would increase ADC contrast pre- and post-treatment, but decrease image quality. Taking into account both CNR and ADC measurement, diffusion-weighted imaging obtained with a b value of 1000 s/mm(2) is recommended for monitoring early hepatic tumor response to TACE.
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Quimioembolización Terapéutica , Imagen de Difusión por Resonancia Magnética , Neoplasias Hepáticas Experimentales/patología , Neoplasias Hepáticas Experimentales/terapia , Modelos Biológicos , Animales , Aumento de la Imagen , Interpretación de Imagen Asistida por Computador , Neoplasias Hepáticas Experimentales/irrigación sanguínea , Masculino , Necrosis , Valor Predictivo de las Pruebas , Conejos , Factores de Tiempo , Resultado del TratamientoRESUMEN
BACKGROUND: The aim of this study was to evaluate the role of computed tomography (CT), Cloquet's node, and disease burden of inguinal lymph nodes (LNs) in predicting pelvic lymph node metastases (LNM) of penile cancer. PATIENTS AND METHODS: Bilateral inguinal lymph node dissection was performed in 73 penile cancer patients and revealed that 33 groin basins exhibited inguinal LNM. RESULTS: Of the 33 groin basins, 16 (48.5%) had pelvic LNM. The sensitivity of pelvic CT in detecting metastatic LNs was 37.5%, and the specificity was 100%. Cloquet's node had a sensitivity of 30.0% and a specificity of 94.1% in pelvic CT-negative groin basins. Pathological characteristics of the inguinal LNs - number of positive LNs, lymph node ratio (number of positive LNs/total number removed), extranodal extension and the expression of p53 - were significantly associated with pelvic LNM. Furthermore, enlarged inguinal LNs = 3 in preoperative CT imaging and lymph node size = 3.5 cm in long diameter were prognostic factors for pelvic LNM (p = 0.001 and 0.003, respectively). CONCLUSION: Pelvic CT imaging and tumor status of Cloquet's node is of limited use in predicting microscopic pelvic LNM. Pathological characteristics of the inguinal LNs remain the essential indicators of pelvic LNM.
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Carcinoma de Células Escamosas/cirugía , Ganglios Linfáticos/patología , Metástasis Linfática/patología , Neoplasias del Pene/patología , Biopsia del Ganglio Linfático Centinela , Tomografía Computarizada Espiral , Carga Tumoral , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/patología , Supervivencia sin Enfermedad , Estudios de Seguimiento , Humanos , Conducto Inguinal , Antígeno Ki-67/análisis , Escisión del Ganglio Linfático , Masculino , Pelvis , Neoplasias del Pene/mortalidad , Neoplasias del Pene/cirugía , Pene/patología , Pene/cirugía , Proteína p53 Supresora de Tumor/análisisRESUMEN
OBJECTIVE: To compare and analyze the MRI features of different renal cell carcinoma (RCC) subtypes. METHODS: The MR images of 81 surgically and pathologically confirmed renal cell carcinomas from 79 patients were reviewed retrospectively. The MR imaging features of lesions in plain scan, the degree and patterns of lesion enhancement (homogeneous, heterogeneous, peripheral), and tumor spreading patterns were analyzed. In order to evaluate the diagnostic validity of differentiating RCC subtypes using signal enhancement, receiver operating characteristic curves (ROC) were generated. The cutoff value of post-contrast signal intensity to noise ratios (SNR) of the tumor parenchyma were also generated in order to differentiate clear cell RCC from other subtypes. RESULTS: Of the 81 lesions, 58 were clear cell carcinomas, 10 chromophobe cell carcinomas, 8 papillary cell carcinomas, and 5 unclassified RCC. All the chromophobe cell subtype tumors showed a homogeneous density (P < 0.05). The clear cell subtype tumors were likely heterogenous, and also showed heterogenous enhancement with mixed signal than other subtypes (P < 0.05). The cutoff value of SNR, which was used to differentiate clear cell subtype from the other subtypes, were 616 (corticomedullary phase), 579 (nephrographic phase) and 278 (excretory phase), retrospectively. The nephrographic phase is the most appropriate for differentiation, with a sensitivity of 62.1%, specificity of 91.3%, positive predictive value of 94.7%, negative predictive value of 48.8% and an accuracy value of 70.3%. No significant difference was found in tumor spreading patterns among all subtypes of RCC. CONCLUSION: MR imaging features, particularly tumor heterogeneity and degree of enhancement are useful in differentiation of the renal cell carcinoma subtypes, and in choosing an individualized therapy.