Biomedical subjects

Jian Cen

Publications and source records attributed to Jian Cen.

4 recordsLinked to original sources

PubMed2004

[Induction of anti-leukemic cytotoxicity by dendritic cells derived from human cord blood in vitro].

The aim was to investigate the cytolytic activity of cytotoxic T lymphocytes (CTL) induced by dendritic cells (DC) derived from human cord blood in vitro. Human cord blood mononuclear cells (CBMNC) were cultured in vitro with addition of various cytokines. DC was confirmed by morphology, immune phenotype and capacity of stimulating MLR (mixed lymphocyte reaction). CTL were generated through the co-culture of autologous T lymphocytes and DC. (51)Cr-release assays were performed for the measurement of cytotoxicity of CTL. The results showed that distribution of the subgroups of T lymphocytes in CBMNC was similar to that in adult peripheral blood. The percentage of CD1a-expressing cells in CBMNC was very low, merely (0.41 +/- 0.09)%. During culture, DC became larger and more irregular in shape. Spiny dendrites or multiple cell processes in morphology emerged on the surface of DC. Among the cell populations at 15 days of culture, there were (28.4 +/- 3.55)% of CD1a-expressing cells, (63.67 +/- 23.33)% of CD86-positive, (8.7 +/- 1.49)% of CD83-positive and (32.5 +/- 1.53)% of HLA-DR-positive cells. DC derived from CBMNC is capable of stimulating the proliferation of allogeneic lymphocytes in MLR. CTL derived from autologous T lymphocytes induced by dendritic cells pulsed with lysates of HL-60 cells, possessed specific cytolytic effects against HL-60 cells. In conclusions, relatively high percentage of CD1a-expressing cells can be generated in culture system of this study. DC derived from cord blood is able to induce the production of anti-leukemic CTL in vitro.

Antigens, CD1↗

PubMed2004

[Inhibitive effect of previously activated psoralens on K562 cell proliferation].

The objective was to observe the influence of previously activated psoralens on the proliferation of K562 cells, and to provide laboratory data for its clinical usage. K562 cells were treated separately with previously and late activated psoralens, then their trypan blue exclusion inhibited rates (TBIR), cell proliferation inhibited rates (CPIR) and colony forming inhibited rates (CFIR) after culture were compared. The results showed that previously activated psoralens displayed an inhibiting effect on the proliferation of K562 cells with a dose-effect relationship. There was no obvious difference between previously and late activated psoralens on TBIR, CPIR and CFIR. In order to exert the inhibitive effect of previously activated psoralens, the time of ultraviolet ray exposure should be 10 minutes at least, and longer than 12 hours for inhibiting K562. The inhibitive effect of previously activated psoratens decreased as the time interval from activation to its use was prolonged. The inhibiting effect of previously activated psoralens was strongest within 6 hours after activation. In conclusion, both previously and late activated psoralens show inhibiting effects on the proliferation of K562, which may be able to use an antineoplastic drug in clinic.

Cell Proliferation↗

PubMed2003

Effects of dehydration on the optical properties of in vitro porcine liver.

BACKGROUND AND OBJECTIVES: It is of crucial importance to determine the effects of dehydration on the optical properties of tissue so that optimization of therapy and device for laser applications in medicine can be made. STUDY DESIGN/MATERIALS AND METHODS: After being incubated directly or indirectly in an oven of 37 degrees C for different periods of time, the porcine liver samples were weighed with an electronic scale and their optical properties were measured by a double integrating sphere system. RESULTS: When samples were incubated directly for 20 hours, the average weight loss was 68.5% +/- 1.2%, and the absorption coefficient and scattering coefficient increased 146.1% +/- 26.9% and 10.8% +/- 1.1%, respectively. In comparison, there was only 21.5% +/- 1.0% of water loss for the control samples, and the absorption coefficient increased 30.7% +/- 7.6%, while the reduced scattering coefficient increased 386.5% +/- 29.7%. The effective attenuation coefficients increased 111% and 103% for dehydration group and control group, respectively. CONCLUSIONS: The absorption coefficient and effective attenuation coefficient increase with dehydration level of tissue. However, there is no direct correlation between dehydration and reduced scattering coefficient.

Animals↗

PubMed2003

Modified laser speckle imaging method with improved spatial resolution.

A two-dimensional map of blood flow is crucial for physiological studies. We present a modified laser speckle imaging method (LSI) that is based on the temporal statistics of a time-integrated speckle. A model experiment was performed for the validation of this technique. The spatial and temporal resolutions of this method were studied in theory and compared with current laser speckle contrast analysis (LASCA); the comparison indicates that the spatial resolution of the modified LSI is five times higher than that of current LASCA. Cerebral blood flow under different temperatures was investigated by our modified LSI. Compared with the results obtained by LASCA, the blood flow map obtained by the modified LSI possessed higher spatial resolution and provided additional information about changes in blood perfusion in small blood vessels. These results suggest that this is a suitable method for imaging the full field of blood flow without scanning and provides much higher spatial resolution than that of current LASCA and other laser Doppler perfusion imaging methods.

Algorithms↗