At present, the experimental technique to produce human red blood cells in vitro is complicated, and in order to optimize the induction steps, human pluripotent stem cells were differentiated into red blood cells through two induction steps. First, human pluripotent stem cells (including Rh negative A type umbilical cord mesenchymal stem cells (hUCMSCRh-A) and human iPS cells (hiPS)) were differentiated into CD31+ and CD34+ cells in BVF medium. PCR and flow cytometry were used to exam the expression of CD31 and CD34. We found that hUCMSCRh-A derived CD31+ and CD34+ cells were 5.3% and 22.7%, respectively; hiPS derived CD31+ and CD34+ cells were 31.2% and 8.2%, respectively. For the second induction step, the obtained CD31+ and CD34+ cells were differentiated into mature erythrocytes for 36 days under the addition of various growth factors. Through Giemsa staining, we found that the obtained mature erythrocytes were similar in morphology and size to normal human erythrocytes, and some obtained erythrocytes were enucleated. Globin expression was detected by real time RT-PCR, and the expression of β-globin was more than 20%. The obtained erythrocytes are collected into the centrifuge tube, and then erythrocytes were naturally settled and showed the red color. Our findings provide a novel and effective method for the quantity generation of human red blood cells in vitro.

Objective To analyze CT characteristics of metastatic liver leiomyosarcoma(MLL),and to improve the diagnostic accuracy of MLL.Methods CT manifestations and clinical characteristics of 5 patients with pathological-proved MLL were retrospectively analyzed.Plain and contrast-enhanced triphase(including arterial,portal phase in all cases and delayed phase in a part of cases) scans were performed.Results On plain scan,all lesions were hypo-dense."Bull-eye-sign" was found in two cases on contrast-enhanced scan,which is the typical metastatic feature.During arterial phase,the smaller lesions showed marked peripheral enhancement and central necrosis.The larger MLL presented as solid-cystic lesions,the parenchyma of tumor was rich in blood supply.Some cases presented mild hypo-dense or iso-dense comparing with the parenchyma of the liver on delayed phase.One case was misdiagnosed as hepatic hemangioma or focal nodular hyperplasia(FNH).Metastases were found out of the liver.Tumor thrombus of portal vein was not found in all of the cases.Conclusion MLL should be considered in the patients with history of extra-hepatic leiomyosarcoma,no marker expressions,no history of hepatitis,no tumor thrombus of portal vein and the special CT findings.