RESUMO
The evolution of the structural and magnetic properties of nanocomposites formed by cobalt ferrite particles dispersed in xerogel and aerogel silica matrices (CoFe2O4/SiO2) have been studied as a function of the temperature of preparation and the amount of ferrite dispersed in the matrix. Wet samples with different amounts of CoFe2O4 in SiO2 matrix were prepared by sol-gel process in monolithic form. Xerogel and aerogel samples were prepared by controlled and hypercritical drying, respectively, and heated at various temperatures between 300 and 1100 degrees C. Superparamagnetic behavior has been observed by magnetization studies at room temperature for xerogels prepared at low temperature. Aerogel samples showed significant superparamagnetic fractions for all thermal treatment temperatures as determined by Mössbauer spectroscopy. Magnetization of the nanocomposites at 10 KOe applied field varied from 1 to 19 emu/g and the coercivity from 90 to 2320 Oe, respectively, for the different morphologies and textures of the analyzed material. The results show that besides the magnetization and coercivity depend on crystallite size, parameters such as ferrite content, porosity and drying conditions greatly influence the nanocomposite magnetic behavior.
RESUMO
Infiltrating micropapillary carcinoma of the breast is a recently described and poorly recognized aggressive variant of infiltrating ductal carcinoma for which the clinical significance and role of prognostic markers are not fully described. In 14 cases of infiltrating micropapillary carcinoma, we studied histologic characteristics; immunohistochemical expression of c-erbB-2, p53, and MIB-1; hormonal expression of these tumors; and genetic alterations on the p53 locus. We correlated these results with clinical outcome. Patient ages ranged from 37 to 58 years (mean, 50 yr). Nine patients presented with a palpable tumor, one with an axillary mass. Three patients had abnormal mammograms. Five patients (36%) presented with Stage II disease, eight (57%) with Stage III, and one (7%) with Stage IV. The tumors were a modified Bloom-Richardson Grade II in nine cases (64%) and Grade III in 5 (36%). Mitoses ranged from 1 to 12 per 10 high power fields. Necrosis was uniformly absent. Psammoma bodies were present in 9 cases (64%) and lymphatic invasion in 10 (71%). In all of the cases, c-erbB-2 was identified immunohistochemically, and MIB-I was positive, staining 30 to 60% of the tumor cells. The cells were immunoreactive for p53 in six (75%) of eight cases, and, when present, stained 20 to 50% of the tumor cells. Loss of heterozygosity on locus 17p13.1 (p53) was identified in 4 of 5 informative samples. Molecular and immunohistochemical analyses had an 80% concordance. Follow-up was available in 11 patients, of whom 9 had recurrence in the skin and chest wall (average time of recurrence, 24 mo). Recognition of this distinctive and aggressive variant of infiltrating carcinoma is important because of its unfavorable prognosis and specific pattern of local recurrence. Its aggressive nature is supported by its advanced stage at presentation and expression of unfavorable prognostic markers.
Assuntos
Neoplasias da Mama/diagnóstico , Neoplasias da Mama/patologia , Carcinoma Papilar/diagnóstico , Carcinoma Papilar/patologia , Adulto , Antígenos Nucleares , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Carcinoma Papilar/genética , Carcinoma Papilar/metabolismo , Carcinoma Papilar/mortalidade , Cromossomos Humanos Par 17/genética , Feminino , Humanos , Imuno-Histoquímica , Antígeno Ki-67 , Perda de Heterozigosidade/genética , Pessoa de Meia-Idade , Proteínas Nucleares/metabolismo , Reação em Cadeia da Polimerase , Prognóstico , Receptor ErbB-2/metabolismo , Taxa de Sobrevida , Proteína Supressora de Tumor p53/metabolismoRESUMO
De 245 escolares del único Centro Educativo No. 4021 del asentamiento Humano "Parque Porcino", Distrito de Ventanilla Callao se ha realizado un estudio de enteroparásitos en 143 de ellos, durante los meses de noviembre y diciembre de 1991 mediante los métodos directo y concentración de Faust. A 179 niños se aplicó el método de Graham para la busqueda de Enterobius vermicularis. De 143 escolares, 117 niños (81.82 por ciento) tenían enteroparásitos, siendo el grupo etareo más afectado el de 8 a 10 años (57.26 por ciento) y el triparasitismo (33.33 por ciento) lo más predominante. De los protozoarios patógenos, Giardia Lamblia es el más frecuente (30.76 por ciento) y entre los helmintos, Hymenolepis nana (26.57 por ciento), hallándose 41.89 por ciento para Enterobius vermicularis. La elevada prevalencia de parásitos intestinales estaría relacionada con las características propias de la zona que incluye las malas condiciones de saneamiento y cultura higiénica de la población estudiada. Se dió tratamiento a los niños con Enterobiasis.