Objective To determine the maintenance and loss of Epstein-Barr virus (EBV) genome during the clonal expansion of the EBV-infected epithelial cells. Methods The epithelial tumor cell line, 293-EBV, in which the EBV genome was observed with green fluorescent protein (GFP) readout. After a dozen of passages, it contained cells with strong or weak GFP expression, and some with complete loss of EBV genome. The cell growth was then continuously observed under a confocal microscope. The cell dividing and GFP expression were also observed during the clonal expansion by being made into very low density. Results The cells moved around due to adherence and mobility, while the GFP expression remained unchanged in the undivided cells. The cells could form compact or loosen clones. The EBV genome easily persisted in those clones when cells were growing compactly. As the cell number increased, the GFP expression became weak or even died away at the sites of low density in the loosen clones. Conclusion EBV-positive epithelial cells are able to sustain the EBV genome during its clonal expansion. The cells maintain EBV genomes by passing them to the daughter cells after replication. When the cells unsuccessfully inherit the EBV genome, the daughter cells may lose them which is related to the low cell density as well as the epithelial environment.

Objective:To investigate the application value of dynamic scintigraphy single-photonemission computed tomography (SPECT) 99m-technetium-galactosyl human serum albumin diethy-lenetriamine pentaacetic ( 99Tc m-GSA) scintigraphy in assessing liver function of perihilar cholangio-carcinoma after portal vein embolization (PVE). Methods:The retrospective and descriptive study was conducted. The clinicopathological data of 16 patients with perihilar cholangiocarcinoma who underwent 99Tc m-GSA scintigraphy after PVE in Beijing Tsinghua Changgung Hospital Affiliated to Tsinghua University from October 2019 to January 2021 were collected. There were 8 males and 8 females, aged from 46 to 78 years, with a median age of 64 years. Observation indicators: (1) liver volume after PVE; (2) liver function after PVE; (3) typical case analysis. Measurement data with normal distribution were represented as Mean± SD. Count data were represented as absolute numbers or percentages. Comparison of data of the same patient was analyzed using the paired t test. Results:(1) Liver volume after PVE:the morphological liver volume and functional liver volume for the 16 patients were (1 420±211)mL and (389±112)mL. The morphological liver volume and functional liver volume were (636±143)mL and (234±106)mL of planning reserved lobe, (784±210)mL and (151±106)mL of planning resection lobe, respectively. The functional liver density (FLD) of planning reserved lobe and planning resection lobe were 0.36±0.12 and 0.19±0.11, showing a significant difference between them ( t=3.794, P<0.05). The planning resection rate of morpholo-gical liver volume and functional liver volume were 37.8%±0.6% and 54.8%±0.2%, showing a significant difference between them ( t=?3.720, P<0.05). (2) Liver function after PVE: 13 of 16 patients completed the indocyanine green (ICG) test, and 3 patients didn't complete the ICG test due to intolerance. For the 13 patients undergoing ICG test, the total ICG-K value was (0.15±0.03)/minutes, and the ICG-K value of planning reserved lobe was (0.07±0.02)/minutes. The total GSA-K value of 16 patients was (0.14±0.10)/minutes, and the GSA-K value of planning reserved lobe was (0.08±0.06)/minutes. (3) Typical case analysis: a 46-year-old male patient with type Bismuth Ⅲa perihilar cholangiocarcinoma was planned to perform perihilar hepatectomy combined with right hepatectomy. The imaging evaluation showed that the volume of reserved liver lobe accounted for 27% of the total liver volume. The serum total bilirubin was 256 μmol/L when admitted and decreased to 118 μmol/L on the day 5 after percutaneous transhepatic biliary drainage. The right anterior and right posterior branches of PVE was performed. SPECT 99Tc m-GSA examination was performed on the day 37 after PVE. The morphological liver volume was 559 mL of planned reserved lobe and 1 461 mL of the whole liver. The planned morphological liver volume resection rate was 61.7%. ICG-K was 0.12/minutes of the whole liver, and 0.04/minutes of planned reserved lobe. The functional liver volume was 134 mL of planned reserved lobe and 309 mL of the whole liver. The planned resection rate of functional liver volume was 56.6%. The GSA-K was 0.20/minutes of the whole liver and 0.09/minutes of planned reserved lobe. R 0 resection was achieved in perihilar hepatectomy combined with right hepatectomy and no liver failure occurred. The survival time of patients was 11 months. Conclusion:Dynamic SPECT 99Tc m-GSA scintigraphy can effectively evaluate the regional function of the reserved liver lobe in patients with perihilar cholangiocarcinoma after PVE.