The experiments was conducted on the fibroblasts of human prepuce in vitro todemonstrate the distribution of cytoplasmic microfilaments with Coomassie Blue R250.It has been found that the distribution of the cytoplasmic microfilaments canbe disturbed by the specific inhibitor,Cytochalasin B.We also observed the inhi-bition by Cytochalasin B was reversible.The cytoplasmic microfilaments regainedtheir normal distribution after the Cytochalasin B was removed.This result further confirmed that the staining method of Coomassie BrilliantBlue R 250 is reliable to demonstrate microfilaments in cultured fibrablasts.

The distribution of receptor sites for concanavalin A (Con A) on the cellsurface of human gastric cancer cell line (MGC 80-3) and fibroblast cell cultures wasstudied with electron and light microscope after application of Con A-peroxidasemethod.The cytochemical reaction of the majority of non-prefixed MGC 80-3 cellsshows a striking tendency to be more uneven distribution than on fibroblasts.Clustering,patching and capping of Con A binding sites on the cancer cells anduniform distribution on the fibroblasts were observed.The effects of incubationtemperature,prefix treatment,different phase of cell cycles and cell growth condi-tions on the distribution of Con A receptor complexes were observed.The possiblereasons for the more irregular distribution of the cytochemical reaction product onthe MGC 80-3 cells than the fibroblasts are discussed.

A rat monoclonal antibody of the IgG1 class, McAb B5A8, specific for the cAMP-dependent protein kinase(PKA) was produced. Western blot analysis revealed specific binding of the antibody to protein of 52-56 kd.The affinity-purified McAb BSA8 was labeled with FITC. Immunofluorescent localization of PKA was examined in human fibroblasts, gastric cancer cell line (MGc 80-3)and EAC cells. The distribution of PKA on the cytoplasmic microtubule network, Golgi region and nucleoli were observed. PKA was localized in the nuclear region in G2 phase of synchronized MGc 80-3 cells, and it was only found around the nuclei of MGc 80-3 cells which were incubated with DBcAMP. The changes in the distribution of PKA in cells are discussed.

Synchronous cells in different phase (G_1, S, G_2, M) of cell cycle were obtained from human gastric low-differentiated mucous adenocarcinoma cells (MGC 80-3), which werec ultured with nitrous oxide under high pressure and blocked with overdosage of TdR. Dynamic changes of the mitochondria stained with Rhodamine-123 and succinate dehydrogenase demonstrated by cytochemical method were observed in various phase of the cells at 0, 24, 36, 60 hours after treatment with HPD plus red light. The results showed that mitochonodria of all four phases are of impairment immediately after photoradiation, SDH reactivity is decreased slightly at 24 hours, the activities of SDH is the weakest. As time goes on, we observed that mitochondria gradually recovered to its original structure and then SDH returned to its normal level. The recovery rate of mitochondria and SDH was in the following order, i. e. S, G_1, G_2, andM. The relationship between these changes and cell killing is briefly discussed.