Objective To investigate the efficient method which can culture and induce embryonic stem cells to neurocyte in vitro. Methods Isolate the blastula of 3.5 d from BALB/c species mouse. Culture the cells from inner cell mass (ICM) which were isolated by mechanical method on the mouse embryonic fibroblaste cell (MEF) feeder layer or 0.1% gelatin coated dishes. The stem cells were identified by characterized morphology, alkaline phosphatase stain, differential potency in vivo and immunochemistry stain. The isolated cells were differentiated by serial induction method that mimicking the intrinsic developmental process of the neural system. Results The isolated cells were positive for alkaline phosphatatse and SSEA-1 (stage specific embryonic antigen 1). Moreover they were identified pluripotent by differentiation in vivo. Therefore the isolated cells presented the characters of ESCs. Then the isolated cells were able to differentiate into neurocytes in vitro. Conclusion Mouse embryonic stem cells isolation, culture and differentiation system has been established.

OBJECTIVE To establish a method to detect the blood concentration of ibrutinib and apply it to the clinic. METHODS Using zanubrutinib as internal standard， the concentration of ibrutinib was detected by high performance liquid chromatography （HPLC） after plasma samples were processed by solid-phase extraction. The separation was performed on an Agilent 5 TC-C18（2） column with acetonitrile-0.5% potassium dihydrogen phosphate solution （43∶57， V/V） as the mobile phase at a flow rate of 1 mL/min， a detection wavelength of 260 nm， a column temperature of 40 ℃ ， a sample size of 20 μL， and a run time of 25 min. The concentration of ibrutinib was measured in the plasma of 9 patients with non-Hodgkin’s lymphoma 2 h after drug administration on the 30th day by the above method. RESULTS The linear range of the assayed mass concentration of ibrutinib was 10-500 ng/mL （R 2＝0.998 9）， the lower limit of quantification was 10 ng/mL， and the RSDs of the intra-batch and inter-batch precision tests were not higher than 12.77%. The recoveries of the extraction were 74.80% and 97.70%， with both RSDs＜2.90%， and the RSDs of the stability tests were not higher than 7.10%. The peak plasma concentrations of 9 patients were 15.341-279.628 ng/mL. CONCLUSIONS The established HPLC method is simple and rapid， and can be used for the determination of ibrutinib concentration in plasma samples.