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To investigate the prevalence of lymph node micrometastasis (LNMM) on the basis of the detection of MUC1 mRNA, and assess the impact of these micrometastases on disease-free interval after resection of pathologic N0 (pN0) esophageal squamous cell cancer (ESCC).The subjects were 93 patients who underwent complete resection of pN0 ESCC at our department between January 1999 and January 2001. All lymph nodes (426 stations) obtained from these patients were reevaluated by reverse transcription-polymerase chain reaction to detect MUC1 mRNA. The diagnosis of LNMM was based on the detection of MUC1 mRNA. A log-rank test was performed to compare the disease-free interval, and Cox regression multivariate analysis was performed to determine the independent prognostic factors.Micrometastasis was detected in 40 lymph node stations (9.4%) from 32 patients (34.4%). Disease-free interval was significantly associated with LNMM (P = 0.0138). The 5-year survival rate of patients with LNMM was significantly lower than that of those without LNMM (P = 0.004). The results of multivariate analysis confirmed that T status and LNMM were independent prognostic factors.The prevalence of LNMM in patients with pN0 ESCC was 34.4% (32/93). Thus, LNMM was significantly associated with the disease-free interval. T status and LNMM were both independent prognostic factors.

To study the effects of subretinal fluid (SRF) on the proliferation of retinal pigment epithelium (RPE) cells and on the activation and translocation of protein kinase C (PKC); to investigate the relationship between the proliferation and the changes of PKC in the RPE cells; and to study the effect of PKC inhibitor.RPE cells were harvested to measure the PKC activity in cytoplasm and cellular membrane after being treated with subretinal fluid (SRF) obtained from PVR patients with different degrees (B grade and C), PKC specific activator PMA (positive control) or normal vitreous. RPE cells cultured with DMEM culture medium only were used as the negative controls. PKC activity in cytoplasm and cellular membrane was measured with radioactive isotope (32)P label method. For further study, the PKC specific inhibitor N, N-dimethyl was used to pretreat the RPE cells before the administration of SRF, PMA or normal vitreous, and then the activity of PKC was observed and recorded. (3)H-TdR was used to measure the proliferation of RPE cells with or without the activation and translocation.SRF and PMA could promote the proliferation of RPE cells and activate PKC in the cytoplasm of RPE cells, and then promoted the PKC translocated from the cytoplasm to cellular membrane. The peak of PRC on the cell membrane appeared later in cells treated with SRF when compared with those treated with PMA. The appearance of peak of PKC in cells treated with SRF from grade B PVR was later than those treated with SRF from grade C PVR, the stimulating effect on the proliferation of RPE cells by the SRF B was also less than those from the SRF C. No activation of PKC and increased proliferation were observed in RPE cells treated with normal vitreous or DMEM culture medium. Pre-treatment with PKC inhibitor could block the PKC-activating effects and proliferation-stimulating effects of SRF and PMA on the RPE cells, therefore no significant difference could be detected between different groups.SRF can promote the proliferation of RPE cells and induce the activation and translocation of PKC in RPE cells. PKC is involved in the process of the proliferation of RPE cells. The PKC inhibitor could block this process.