Interventional effect of Ginkgo biloba extract on the progression of gastric precancerous lesions in rats.

OBJECTIVE: To investigate the effect of Ginkgo biloba extract on gastric precancerous lesions in rats. METHODS: 80 4-week-old Wistar rats were randomly divided into four groups: a control group, a model group, a low and a high dose Ginkgo biloba extract intervention group; 20 in each group. Gastric precancerous lesions were induced by giving them 100 mg/L N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) solution to drink ad libitum for 20 weeks. In addition to the MNNG, the intervention groups were lavaged with Ginkgo biloba extract (0.5 mg/kg/d in the low dose group, 1.5 mg/kg/d in the high dose group) for 20 weeks. Starting from week 21 all the rats were fed with normal rat chow and tap water. At the end of week 30 the rats were killed. The histopathological changes of their gastric mucosa, ISA, NGI, the serum and gastric mucosal SOD/MDA and the expressions of oncogenes were studied. RESULTS: The incidence of mild to severe intestinal metaplasia and dysplasia were significantly lower in the intervention groups than those in the model group (P < 0.01). The ISA and NGI in the intervention groups were significantly lower than those in the model group (P < 0.01). In the intervention groups the activity of SOD was increased and the concentration of MDA was decreased (P < 0.01). Expressions of Bcl-2, c-myc and FasL decreased in the intervention groups, whereas the expression of Fas increased. When compared with the model group, the differences were statistically significant (P < 0.01, P < 0.05, respectively). CONCLUSION: Ginkgo biloba extract can increase anti-oxidative activity and inhibit the progression of gastric precancerous lesions via the regulation of cell proliferation and apoptosis.

Use of potassium dihydrogen phosphate and sawdust as adsorbents of ammoniacal nitrogen in aerobic composting process.

Three kinds of adsorbents-potassium dihydrogen phosphate, sawdust and mixture of potassium dihydrogen phosphate and sawdust were added respectively into composting to investigate their adsorption effect on ammonia. The experimental results showed that all the adsorbents could restrain ammonia volatilizing, with the sorption of potassium dihydrogen phosphate adsorbents being the best of all, the sorption of mixture adsorbent with potassium dihydrogen phosphate and sawdust being the second and the sorption of sawdust adsorbent being the last. Therefore, the total nitrogen loss ratios respectively reduced from 38% to 13%, 15% and 21% after adding these three kinds of adsorbents into composting. However, potassium dihydrogen phosphate produced negative influence on composting properties as its supplemented amount exceeded a quantity basis equivalent to 18% of total nitrogen in the composting, for example: pH value had been lessened, microorganism activity reduced, which finally resulted in the reduction of biodegradation ratio of organic matter. But it did not result in these problems when using the mixture of potassium dihydrogen phosphate and sawdust as adsorbent, in which the amount of potassium dihydrogen phosphate was under a quantity basis equivalent to 6% of total nitrogen in the composting. Moreover, the mixture adsorbent produced better adsorption effect on ammonia, and raised biodegradation ratio of organic matter from 26% to 33%.