周期性压力下椎间盘细胞中肌动蛋白的变化及其意义

目的探讨在周期性压力下,体外培养的椎间盘细胞中的肌动蛋白的变化及其意义。方法采用10只5～6周龄、体重为25～30kg的猪的椎间盘进行体外细胞的分离和培养,对细胞施加周期性液压,通过对细胞的形态学观察及Western免疫印迹和免疫荧光实验,检测在周期性压力下椎间盘细胞中的肌动蛋白的变化。结果纤维环细胞和髓核细胞经1MPa、1Hz,持续每天3h加压,3d后髓核细胞的存活率大于90%,纤维环细胞的存活率大于85%,加压后的纤维环细胞和髓核细胞体积均缩小,由多角形转变为细长形。Western免疫印迹结果显示,肌动蛋白在纤维环细胞和髓核细胞中的表达均明显减少,以髓核细胞为著。免疫荧光结果显示,肌动蛋白由正常纤维环细胞和髓核细胞内的疏松排列转变为受压细胞内的紧密排列,髓核细胞的体积明显缩小,其中的肌动蛋白在细胞膜周围紧密排列。结论体外培养的单层椎间盘细胞在受力状态下,肌动蛋白的表达减少,细胞的体积缩小,并且肌动蛋白在细胞内重排列。这可能是激发细胞内或细胞表面信号传导的重要机制。     

Meniscal tears: MR demonstration of experimentally produced injuries

Magnetic resonance (MR) imaging was performed using a 1.5-T magnet on eight immature swine knees with surgically produced vertical and horizontal meniscal tears. Three radiologists, interpreting the images independently, detected all tears. Tears in the middle portion of the meniscus were best seen on sagittal views, while lesions of the anterior and posterior horns of the meniscus were best seen on coronal views. MR has several advantages over arthrography, the current diagnostic method for knee injuries: it is noninvasive, uses no ionizing radiation, and provides excellent soft-tissue contrast resolution.     

Body weight and ABO blood types: Are AB females heavier?

Four samples from widely separated and culturally distinct populations—U.S. college students, Mennonites, Egyptian villagers, and Brazilian migrants—are examined for evidence of a relationship between ABO blood type and body weight. Overall, the results do not support the existence of such a relationship, although they do offer further support to the possibility that females of AB blood type are consistently the heaviest phenotype. © 1994 Wiley-Liss, Inc.     

Candida esophagitis: accuracy of radiographic diagnosis

Candida esophagitis was diagnosed radiographically in 106 patients. Endoscopy was performed in 32 of these patients, and the diagnosis was confirmed in 27. The diagnosis was missed radiographically in seven other cases proved endoscopically. Thus, Candida esophagitis was diagnosed on esophagography in 80% (27/34) of proved cases, with five false-positive examinations. Single-contrast technique was employed in nine cases with a sensitivity of 55%, and double-contrast technique was used in 25 cases with a sensitivity of 88%. With double-contrast technique, esophagography appears to be a more accurate method for diagnosing Candida esophagitis than has been suggested in the literature.     

Identification and characterization of a differentiation-specific antigen on normal and malignant murine erythroid cells

Rauscher murine erythroleukemia cells grow continuously in vitro and undergo terminal differentiation in response to the physiological inducer erythropoietin. In the course of this developmental process they express many erythroid-specific markers. In order to investigate the expression of cell surface determinants during Rauscher cell differentiation we generated monoclonal antibodies to uninduced cells. Using an anti-Rauscher cell monoclonal antibody, we have identified a cell surface determinant, designated ERY-1, that is present on normal murine erythroid cells. This determinant is apparently absent from the early progenitor BFU-E, but is present on the more mature progenitors CFU-E and CFC-E. It disappears during erythroid maturation and is absent from the mature erythrocyte. This pattern of ERY-1 expression is exhibited with remarkable fidelity during the erythropoietin-induced differentiation of Rauscher cells. Such differentiation-specific expression of the ERY-1 determinant suggests that it may play a functional role in erythropoiesis.