The experiment was carried out on Hepatoma-22 ascitic tumor cells of mice in vivo. Daily injection of 2 mg cAMP with 1 mg theophylline into the peritoneal cavity for 7 and 8 days, then these animals were sacrificed. We found that cAMP with theophylline inhibit the growth of tumor cells of Hepatoma-22 ascitic and decrease the activity of Mg~(++), (Na~+-K~+)-ATPase and cAMP-PDE on the cell surface of H-22 tumor cells of mice by cytochemical electron microscopy. Exogenic cAMP and theophlline decrease the activities of these enzymes and elevate the intracellular content of cAMP. These may indicate the reversion transformation of the cancer cell.

The experiment was carried out on cultured human stomach glandular carcinoma (SGC-7901 cell line). We previously reported the cytochemical changes of (Na~+-K~+)-ATPase activity and the changes of microvilli. We here studied the relationship among the cAMP, cAMP-PDEase, Mg~(++)-ATPase activity, the cell growth and differentiation. Cells were exposed to Immol/L cAMP together with 1 mmol/L theophylline. We showed cAMP specific fluorescence by immunocytochemical method, Mg~(++)-ATPase and cAMP-PDEase activity by cytochemical methods. We found that cAMP with theophylline not only inhibited the growth of these SGC-7901 cells as shown by our previous result, but also decreased the activity of Mg~(++)-ATPase and 3', 5'-cyclic monophosphate phosphodiesterase. The result indicates that exogenous cAMP can inhibit 3', 5'-cAMP-PDEase and Mg~(++)-ATPase activity and increase cAMP level in cell, and cAMP regulated the growth and differentiation of SGC-7901 cell line

Objective To observe the relationship between plasma level of homocysteine(HCY) and ischemic stroke in young and middle-aged adults,explore the clinical signficance concerning the occurrence and development of ischemic stroke in young and middle-aged adults.Methods The plasma homocysteine level of 132 young and middle-aged adults patients with ischemic and 86 control peoples were measured by means of enzymatic cycling assay.Results The plasma homocysteine level in ischemic stroke was higher than that in control group( P ＜ 0.01 ).The higher the plasma homocysteine level,the larger infarcted focus in acute ischemic stroke group of young and middleaged adults.The plasma homocysteine level and the infarcted focus was positively linearly correlated.Conclusion Hyperhomocysteinemia is a risk factor of ischemic stroke among young and middle-aged adults.The higher the plasma homocysteine level,the larger infarcted focus in acute ischemic stroke group.The plasma homocysteine level can reflect the size of the infarcted focus and the degree of disease,and the plasma homocysteine level should serve as a kind of regular examination or as an index intervention can be taken,all of which are great importance to prevent ischemic stroke and reduce its morbilily.