Objective To study the significance and expression of gelatinase A in human gastric cancers (GC). Method Gelatinase A expression in 36 cases of GC was examined by immunohistochemistry method. Results Expression of gelatinase A in GC (31/36) was much higher than that in paratumor tissues (7/18) or normal gastric tissues (2/14). There was no obvious correlation between the total gelatinase A staining and tumor size, Lauren typing . Intense expression of gelatinase A was freguently found in the advanced cancer, especially in GC with serosal invasion and lymph node metastasis, while expression of gelatinase A was not found in the early stage GC. Gelatinase A was shown to be expressed in the extracellur matrix of tumor tissues. The staining positive cells were mainly macrophages. Conclusions Gelatinase A expression could be used as a marker for evaluating the invasion and metastasis of GC. Macrophages may play an important role in this process.

To divide the lung from the original X-ray image, the maximum classes square error is employed in finding the threshold. Then the thorax is ascertained according to the edge-detection and tracking-bug method, and the lung is divided from the thorax by the thresholding segmentation method. The gray mean in the lung is regarded as the eigenvalue to identify the image, but it doesn not work well. In view of the dosage of the X-ray exposure and the difference between persons, a new method that adopts the ratio of the gray in lungs to the gray in bones as the eigenvalue is brought forward to identify the image. And the two methods are compared by using the distance between classes. The result shows that the second method is more effective.
Humans ; Lung ; diagnostic imaging ; Radiographic Image Interpretation, Computer-Assisted ; methods ; Respiration