Hepatic oval cells (HOCs) are recognized as facultative liver progenitor cells that play a role in liver regeneration after acute liver injury. Here, we investigated the in vitro proliferation and differentiation characteristics of HOCs in order to explore their potential capacity for intrahepatic transplantation. Clusters or scattered HOCs were detected in the portal area and interlobular bile duct in the liver of rats subjected to the modified 2-acetylaminofluorene and partial hepatectomy method. Isolated HOCs were positive for c-kit and CD90 staining (99.8% and 88.8%, respectively), and negative for CD34 staining (3.6%) as shown by immunostaining and flow cytometric analysis. In addition, HOCs could be differentiated into hepatocytes and bile duct epithelial cells after leukemia inhibitory factor deprivation. A two-cuff technique was used for orthotopic liver transplantation, and HOCs were subsequently transplanted into recipients. Biochemical indicators of liver function were assessed 4 weeks after transplantation. HOC transplantation significantly prolonged the median survival time and improved the liver function of rats receiving HOCs compared to controls (P=0.003, Student t-test). Administration of HOCs to rats also receiving liver transplantation significantly reduced acute allograft rejection compared to control liver transplant rats 3 weeks following transplantation (rejection activity index score: control=6.3±0.9; HOC=3.5±1.5; P=0.005). These results indicate that HOCs may be useful in therapeutic liver regeneration after orthotopic liver transplantation.

Radioactive sources excite scintillators, causing them to emit fluorescence, and are thus widely used in studies of the performance of scintillators. Ultraviolet (UV) light-emitting diodes (LEDs) can also excite scintillators to produce fluorescence. In this paper, the waveform characteristics of a UV LED-excited scintillator detector are studied and compared with the characteristics obtained when using a radioactive source. Test results show that the trailing edge of the scintillation pulse excited by the UV LED has exponential decay characteristics that are similar to those obtained under 137Cs excitation. The light intensity of the UV LED shows a good linear relationship with the peak position of the pulse. Furthermore, a macroscopic model for the output waveform from the scintillator when excited by a UV LED is established and the model is modified based on the experimental results. Although the scintillator's response to the UV source cannot simulate its response to gamma-ray sources fully, we hope that this method can be used in preliminary testing of scintillation detectors or when the use of radiation sources is limited.