ABSTRACT
Silver nanoparticles ( AgNP) , the metallic silver par-ticles with the diameter of 1 ~100 nm are now widely used in many fields. Many researches show that the smaller size of Ag-NP, the stronger toxicity it shows. Generally speaking, AgNP with 20 nm shows strongest toxicity. After entering the body, they are distributed in different organs in the body, and the dis-tribution in the kidney shows a certain gender difference. They also produce some toxic effects after entering body organs. AgNP often exhibit dose effect on the toxicity in vitro cells,while in vivo experiments, their toxic effects change with the different objects and ways of acting. In addition, AgNP can produce toxic effects on reproduction, and may cause parental reproductive activity to deteriorate, and pass the toxic effects to offspring through the placenta to exert a negative influence on the growth and develop-ment of the offspring. The toxicity mechanisms of AgNP are oxi-dative stress injury caused by producing free radicals;metabolic disorders caused by reducing of drug metabolic enzyme activity;and also related gene expression defects and certain molecules, such as transcription factor NF-E2-related factor 2(Nrf2) prote-ase caused by abnormal expression. In short, AgNP can be toxic to organisms, and we must evaluate their biological safety when we use it, to minimize or even avoid the danger it brings about.
ABSTRACT
Objective To evaluate the various patterns of hepatic perfusion disorders with multi-slice spiral CT and to emphasize the significance of recognition for them . Methods In a period of 1 year, the all CT images of 1568 patients received multi-slice spiral CT examination of upper abdomen were analyzed retrospectively. The CT findings, etiologies and mechanisms of different pattens of hepatic perfusion disorders were investigated. Results 103 cases were demonstrated to have hepatic perfusion disorders. 69 cases were associated with tumors and the other 34 cases were non-tumor associated. The etiologies of various hepatic perfusion disorders were classified as (1)arterioportal fistulae(41.7%), (2) portal venous inflow obstruction(23.3%), (3) inflammartory hyperemic changes(17.5%), (4) steal phenomenon by hypervascular tumors(6.8%), (5) hepatic venous outflow obstruction(4.9%), (6) aberrant hepatic blood supply (3.9%) and (7) uncertain causes(1.9%). There was significant correlation between the CT images of perfusion disorders in shape and distribution and the causes of them. Conclusion Multi-slice spiral CT provides a new effective technique for demonstrating and understanding various hepatic perfusion disorders. Familiarity with the spiral CT appearances of these perfusion disorders will result in more accurate evaluation for various pathologic or physiologic states reflected by them.