【Abstract】Objective To study the effects of nitric oxide (NO) on the growth and metastasis of tumor.Methods The literatures of recent years were reviewed.Results NO had double effects on the growth and metastasis of tumor. NO promoted the growth and metastasis by regulating the expression of tumor proliferation gene and inducing tumor angiogenesis. On the other hand, NO had antitumor effects by interfering with the metabolism of tumor cells, inducing the damage of DNA, forming high toxic free radical, inducing apoptosis of tumor cells and mediating the antitumor action of endothelial cells and macrophages.Conclusion Selective blockage or induction of synthesis of NO may be a new way for tumor therapy.
Objective To compare the biological and biomechanical characteristics of decellularized bovine jugular venous tissue-engineered valved conduit scaffolds with that of fresh bovine jugular veins. Methods Fortyeight fresh bovine jugular veins were divided into control group and experimental group with random number table method, 24 veins in each group. There were fresh bovine jugular veins in control group, decellularized bovine jugular veins in experimental group. The veins of experimental group were treated with sodium deoxyeholate plus Triton-X-100 to decellularize the cells in valves and vessel walls. The thickness, water absorption rate, water maintenance rate, destroying strength, stretch rate of valves and vessel walls in two groups were detected. Results The endothelial cell and fibroblast of valves and vessel walls in experimental group were completely decellularized, no cell fragments were retained within the matrix scaffold; collagen fiber and elastin fiber had been preserved with intact structure and wavily arrayed; deoxyribonucleic acid content of valves and vessel walls in experimental group were decreased by 97.58%, 97.25% compared with that of control group. The thickness, water absorption rate and water maintenance rate of valves and vessel walls in experimental group were lightly increased than those of control group, but there were no significant differences between them （P 〉 0. 05）. There were no significant differences in destroying strength and stretch rate of valves and vessel walls between two groups （P〉0. 05）. Conclusion Decellularized bovine jugular vein scaffold has stable biological and biomechanical characteristics and it may be ideal natural fibrous matrix for developing the tissue-engineered valved conduit by host recellularization.
Objective To investigate the effect of WO-1 on the proliferation and differentiation of human embryonic osteoblasts (HEO) and to provide research methods of bone tissue engineering. Methods HEO were isolated from periosteum and calvaria and then cultrued in vitro. The doseeffect relationship between WO-1 concentration and biological effect of HEO was evaluated by growth curve and 3 H-TdR count. The effect of WO-1 on cell activity and proliferation was investigated by cloning efficiency,cell cycle analysis was determined by flow cytometer and morphological was examined through transmission electron microscope. Moreover, the effect of WO-1 on osteoblastic function was evaluated at protein and mRNA levels by ALP activity, 3 H-proline incorporation, osteocalcin secretion (RIA) and mRNA expression of type I collagen and osteocalcin (RT-PCR). Results The proliferation of HEO was inhibited in high concentration of WO-1,while it was promoted in low concentration of WO-1. The optimal dose was 8 μg/ml, and there was dose-effect relationship in the certain range of WO-1 concentration (0.25 μg/ml to 8 μg/ml). In 8 μg/ml of WO-1, the cloning efficiency and cloning volume of HEO were inereased, population doubling time was decreased.All indexes of ostoblastic function including ALP activity, type I collagen synthesis and osteocalcin secertion were inereased, the more sufficed cell organs were observed under transmission electron microscope than control group(P＜0.05). Conclusion WO-1 can promote the cell activity and proliferation of HEO cultured in vitro inlow concentration, enhance the synthesis of extracellular mamix, such as type Icollagen and osteocalcin, and accelerate the mineralization of osteoid. WO-1 can be used as a stimulant of proliferation and differentiation of HEO in the research of bone tissue engineering, which provide the theoretical basis in clinical application.
The chitin abstracted from silkworm chrysalis was subjected to toxicological study including: (1)systematic toxicological test, (2)pyretogenic test, (3)primary cutaneous irritative test, (4)intradermal injection test, (5)cutaneous allergic test. (6)conjunctival irritative test, (7)hemolysis test, (8)bacterial toxicity test, (9)dominant lethal test, and (10)mutagenetictest. The results showed that chitin is atoxic, non-irritative, non-allergenic, nonpyretogenic, non-hemolytic, non-mutagenic, and non-lethal mutagenic. Therefore, chitin is a compatible biomaterial for implanting into the tissue.