Biomedical subjects

Ji-ye Cai

Publications and source records attributed to Ji-ye Cai.

4 recordsLinked to original sources

PubMed2006

[Study of DNA damage induced by potassium dichromate and glutathione with atomic force microscope].

OBJECTIVE: To observe calf thymus DNA damage induced by potassium dichromate in combination with glutathione (GSH). METHODS: Atomic force microscope and ultraviolet spectrum (UV) were used to observe the alterations of the DNA ultrastructure and absorption spectrum. RESULTS: Atomic force microscopy revealed no breaks of the DNA strand in response to treatment with potassium dichromate alone, but when coupled with GSH at proper concentrations, potassium dichromate induced alterations in the DNA structure and DNA fragmentation. UV examination also confirmed these findings by showing increased absorption intensity of the maximum UV peak following combined treatment of the DNA with potassium dichromate and GSH. CONCLUSION: These morphological and spectrographic evidences verified the important role of GSH in mediating the generation of various tumor-inducing intermediate products of potassium dichromate.

Animals↗

PubMed2005

[Directional differentiation of embryonic stem cells into biliary epithelium cells in vitro: an experiment with mice].

OBJECTIVE: To investigate the mechanism and regulation of differentiation from embryonic stem (ES) cells into biliary epithelium (BE) cells and to find a new source f of BE cells for liver engineering. METHODS: ES cells of BALB/c mice (BALB/c-ES) and ES cells of mice of the line 129 (D3-ES) were cultured in the medium without LIF for 5 days with the result that embryoid bodies (EBs) were developed from the ES cells. For directional differentiation, the EBs were plated onto a 24-well gelatin-coated tissue culture dish and some growth factors, such as transforming growth factor (TGF), acid fibroblast growth factor (aFGF), hepatocyte growth factor (HGF) and epidermal growth factor (EGF) etc were added into the medium successively in the experiment group but not in the control group. The differentiation status was observed by inversion microscope dynamically. The BE cell markers, such as cytokeratin 7 (CK7), cytokeratin 19 (CK19) and gamma-glutamyltransferase (GGT) were detected by immunocytochemistry (ICC) and histochemistry. RESULTS: After the culture for 5 days the ES cells developed into many EBs in the medium without LIF. In the EBs cells clusters, many circular structures appeared on the differentiation day 10. On the days 10 and 13 ICC, CK7 and CK19 began to be expressed respectively. GGT began to be expressed at day 10. CK7, CK19 and GGT were also expressed in the ES cells of the control group, however, appeared remarkably later. CONCLUSION: ES cells can differentiate into BE cells under specific culture condition and the action of growth factors. Such ES cell differentiating system can provide BE cells and may serve as a good new source of differentiated cell types for liver engineering.

Animals↗

PubMed2003

[Directional development and differentiation of mouse embryonic stem cells into hepatocytes in vitro].

OBJECTIVE: To investigate the mechanism and regulation of differentiation from embryonic stem (ES) cells to hepatocytes in vitro and to find a new source of cell types for hepatocytes replacement therapies in the treatment of hepatic failure. METHODS: ES cells of BALB/c mice were cultured and maintained undifferentiated in gelatin-coated dishes in Dubecco's modified Eagle's medium (DMEM) containing 1 000 U/L leukaemia inhibitory factor (LIF). Then, the ES cells were cultured in DMEM without LIF so as to develop into embryonic bodies (EBs). For directional differentiating, EBs were put into 24-well tissue culture dish and differentiate into cells with different forms. On day 7 to day 11 acid fibroblast growth factor (aFGF) with terminal concentration of 100 ng/ml was added, and on day 11 to day 15 hepatocyte growth factor (HGF) terminal concentration of 20 ng/ml was added. EBs in culture without growth factor was used as controls. The development and differentiation status was observed by inversion microscope dynamically. The concentrations of alpha-fetoprotein (AFP) and albumin (ALB) in the supernatants were determined by radioimmunoassay on the 1st to 15th day since the ES cells were inoculated. Immunocytochemistry (ICC) was used to detect the expression of hepatic proteins such as AFP, ALB, cytokeratin 8 (CK8) and cytokeratin 18 (CK18) in the cells on the days 7, 8, 9, 10, 11, 12, 13, 14, and 15. The number of ALB positive cells was counted. The ALB positive rate was calculated as the differentiation ratio of hepatic cells. RESULTS: ES cells remained undifferentiated and grew to ES clones in the DMEM containing LIF and developed to EBs in the medium without LIF. AFP was detected firstly in the medium on day 8 with a concentration of 3.4 ng/ml and the concentration increased to be 22.8 ng/ml at day 15; ALB was detected firstly in the medium on day 11 with a concentration of 0.2 microg/ml and the concentration increased to be 2.2 microg/ml on day15. ICC showed that AFP, ALB, CK8, and CK18 began to be expressed on day 8, day 10, day 10, and day 11 respectively. The ICC-positive cells have the ultrastructures consistent with those of the normal mouse hepatocytes. The ratio of hepatic differentiation was 30%. CONCLUSION: ES cells can differentiate directionally into hepatocytes when cultured in gelatin-coated dish and medium with aFGF and HGF. This ES cell differentiating system provides enough functional hepatocytes and may be a good new source of differentiated cell types for hepatocytes replacement therapies in treatment of hepatic failure.

Albumins↗

PubMed2003

[Surface morphology of CD34+ cells under atomic force microscope].

OBJECTIVE: To observe the difference in surface morphology and structure between CD34(+) cells from normal human subjects and from patients with leukemia. METHODS: Bone marrow mononuclear cells from 3 normal human subjects and 3 patients with M2b leukemia were collected by Percoll gradient centrifugation, followed by purification of CD34(+) cells by means of immunomagnetic bead separation (MiniMAC) and examination with flow cytometry. The morphology of the cells were then observed with optical and atomic force microscope (AFM) in air. RESULTS: No significant difference was identified between the two cells under optical microscope. With atomic force microscope, numerous microvilli were observed on the surface of CD34(+) cells, and the normal cells and those from the leukemic patients showed significant difference in terms of the roughness of the cell surface. CONCLUSION: Normal CD34(+) cells have more rough and erosive surface structure than leukemic CD34+ cells (M2b).

Antigens, CD34↗