RESUMO
A method of ultrasonic three-dimensional (3-D) vector velocimetry, which is derived by extending the previously proposed two-dimensional (2-D) vector velocimetry, is presented. In the proposed method, the three vector components of velocity to be measured are defined as the velocity in the beam axial direction, and angle velocities in two transverse directions. To derive the three components of velocity, signals detected by a 2-D array transducer are first 2-D Fourier transformed in the spatial domain parallel to the 2-D array transducer and then are one-dimensional (1-D) Fourier transformed in the time domain. The advantage of the proposed method is that it uses a linear signal processing, so it can simultaneously measure individual velocities of multiple scatterers. Computer simulations clearly demonstrate the effectiveness of the proposed method.
Assuntos
Simulação por Computador , Reologia , Processamento de Sinais Assistido por Computador , Análise de Fourier , Modelos Cardiovasculares , TransdutoresRESUMO
Mutations of the APC gene frequently occur in sporadic forms of colorectal adenomas and adenocarcinomas. Phenotypically, the vast majority of these mutations result in the truncation of the APC protein. To demonstrate the defective APC gene product in human colorectal tumors, rabbit region-specific antisera raised against the APC protein of amino acid sequences between 371 and 390 (SPI) and between 1821 and 1840 (SP3) were used to exhibit the truncated APC protein. In all, 86 lesions from 67 cases of sporadic adenoma and adenocarcinoma were examined; abnormal staining patterns were distinguished in 43 lesions (50%); the incidence of abnormalities was not significantly different between adenomas and carcinomas. The majority, 75% exhibited epitopic change with the SPI-positive and SP3-negative phenotype (type P1), and 25% exhibited neither of these phenotypes (type P2). The staining pattern in all lesions was uniform, and studies of carcinomas arising in adenomas showed the same pattern of staining. These findings supported the view that the APC lesion is a very early event in colorectal carcinogenesis. Furthermore, this simple immunohistochemical approach demonstrated that different adenomas from the same patient showed different staining patterns.
Assuntos
Adenocarcinoma/química , Adenoma/química , Neoplasias Colorretais/química , Proteínas do Citoesqueleto/análise , Adenocarcinoma/patologia , Adenoma/patologia , Proteína da Polipose Adenomatosa do Colo , Sequência de Aminoácidos , Animais , Western Blotting , Neoplasias Colorretais/patologia , Proteínas do Citoesqueleto/química , Proteínas do Citoesqueleto/genética , Regulação Neoplásica da Expressão Gênica , Genótipo , Humanos , Imuno-Histoquímica , Dados de Sequência Molecular , Fenótipo , CoelhosRESUMO
A new noninvasive method of measurement of the intracardiac blood flow by means of ultrasound techniques is described. In this system the "M-sequence modulated Doppler method" and the method of ultrasonotomography are used in combination. An arbitrary space within the heart can be selected by ultrasonocardiotomography and the blood flow profiles can be observed by the "M-sequence modulated Doppler method." The new Doppler flow meter system described in this paper can be applied not only for the diagnosis of heart diseases, but also for the study of pathophysiology of the blood flow and of the factors responsible for the dilatation of the heart. Further studies are required from the viewpoints of medicine and engineering to accumulate sufficient data before routine application of the method described in this paper is fully warranted.
