Biomedical subjects

Dayong Jin

Publications and source records attributed to Dayong Jin.

3 recordsLinked to original sources

PubMed2006

High intensity solid-state UV source for time-gated luminescence microscopy.

BACKGROUND: The unique discriminative ability of immunofluorescent probes can be severely compromised when probe emission competes against naturally occurring, intrinsically fluorescent substances (autofluorophores). Luminescence microscopes that operate in the time-domain can selectively resolve probes with long fluorescence lifetimes (tau > 100 micros) against short-lived fluorescence to deliver greatly improved signal-to-noise ratio (SNR). A novel time-gated luminescence microscope design is reported that employs an ultraviolet (UV) light emitting diode (LED) to excite fluorescence from a europium chelate immunoconjugate with a long fluorescence lifetime. METHODS: A commercial Zeiss epifluorescence microscope was adapted for TGL operation by fitting with a time-gated image-intensified CCD camera and a high-power (100 mW) UV LED. Capture of the luminescence was delayed for a precise interval following excitation so that autofluorescence was suppressed. Giardia cysts were labeled in situ with antibody conjugated to a europium chelate (BHHST) with a fluorescence lifetime >500 micros. RESULTS: BHHST-labeled Giardia cysts emit at 617 nm when excited in the UV and were difficult to locate within the matrix of fluorescent algae using conventional fluorescence microscopy, and the SNR of probe to autofluorescent background was 0.51:1. However in time-gated luminescence mode with a gate-delay of 5 mus, the SNR was improved to 12.8:1, a 25-fold improvement. CONCLUSION: In comparison to xenon flashlamps, UV LEDs are inexpensive, easily powered, and extinguish quickly. Furthermore, the spiked emission of the LED enabled removal of spectral filters from the microscope to significantly improve efficiency of fluorescence excitation and capture.

Animals↗

PubMed2002

[Therapeutic effects of human interleukin 10 gene transfer on severe acute pancreatitis in rats, an experimental study].

OBJECTIVE: To study the therapeutic effects of human interleukin 10 (IL-10) gene transfer on severe acute pancreatitis (SAP) in rats. METHODS: Twenty healthy SD rats were injected intraperitoneally with SA liposome, SA liposome/pcDNA3 or SA liposome/pcDNA3-IL-10. Another twenty SD rats were randomly divided into five groups: rats in one group underwent laparotomy only (normal control), and SAP was induced in the other 4 groups induced by homogeneous injection of sodium taurocholate beneath the pancreatic capsule. Among the 4 SAP groups, one group did not receive any drugs, and liposomes, pcDNA3 or pcDNA3-IL-10 complexed with cationic liposomes were administered to the other groups. Drugs were administered by a single intraperitoneal injection thirty minutes after SAP had been induced. The levels of IL-10 in pancreas, liver and lungs were determined by ELISA kits. The level of serum amylase, histology, and tissue tumor necrosis factor (TNF) were assessed and mortality rate was observed in different groups for one week. RESULTS: The levels of IL-10 in the pancreas, liver and lung 24 hours after IL-10 gene transfer, increased significantly (all > 350 pg/g), and then gradually decreased, however, the levels of IL-10 were still significantly higher that those in the control groups (P < 0.05) 96 hours later and decreased to normal in one week. The levels of IL-10 of transfer control group were not significantly different from those of the normal control group. The levels of IL-10 expression in pancreas, liver and lungs were increased significantly in the gene therapy group, compared with the SAP group. The serum amylase level was (4 300 +/- 700) U/L in normal control group, increased to (20 300 +/- 1 100) U/L 24 hour after SAP induction without a difference between the therapy control group and SAP group, and decreased to (6 800 +/- 700) U/L after IL-10 gene therapy (P < 0.05). The histological score of pancreas was 4.1 +/- 0.2 24 hours after the induction of SAP, and was 3.2 +/- 0.3 in the IL-10 therapy group. The level of TNF in pancreas, liver, and lungs 24 hours after the induction of SAP was significantly higher than that in normal control group (P < 0.05) and was not different from that in therapeutic control group. However, it was decreased markedly in IL-10 therapy group (P < 0.05). No rat in any group died within 2 days after onset. There was no difference of mortality between SAP group and therapeutic control group. The one-week mortality was 90% in the whole SAP group. The one-week mortality of IL-10 gene therapy group was 30 %, significantly lower than that in SAP group (P < 0.05). There was no significant difference in the therapeutic control groups and the SAP group. The values of relative risk of SAP group, SA liposome group, and pcDNA3 group were 12, 8, and 11 times higher than that of gene therapy group (P < 0.05). CONCLUSION: Cationic liposome mediated pcDNA3-IL-10 gene therapy decreases significantly the severity and mortality of SAP.

Amylases↗

PubMed2002

[Anti-tumor effect through human endostatin gene transfer in mice bearing B16 melanoma].

OBJECTIVE: To investigate the effects of direct intratumor injection of the packaged cells with retroviral vector carrying human endostatin (hEN) on the growth inhibition of B16 melanoma in C57/BL6 mice. METHODS: Retroviral vector, pLNC-hEN, was constructed with modified and identified hEN gene. The cell line, PA317, was used to establish ecotropic virus producing cells by transfecting and packing with pLNC-hEN. Then the cells were injected directly into the tumor in C57/BL6 mice bearing B16 melanoma, established by intra-cutaneous injection of B16 cell suspension. The tumor size was measured at different intervals to observe the antitumor effect. Micro-vessel density (MVD) in the tumor tissue was evaluated by immunohistological examination to count the apoptotic cells by TUMEL staining. RESULTS: Tumor with diameter of 2 - 3 mm was observed in all mice after 7 - 9 days. The average tumor volume on D3, D5, D7 and D9 after gene transfection was 4.67 +/- 1.1, 22.25 +/- 13.06, 84.17 +/- 43.5 and 155.08 +/- 81.1 mm(3) in the gene therapy group but 136.17 +/- 30.61, 390.17 +/- 220.47, 1 021.67 +/- 537.4 and 2 920.2 +/- 220.01 mm(3) in the control group, the difference of which was statistically significant. The average MVD in the gene therapy and control groups were 8 +/- 2.28 and 28.17 +/- 5.31 while the average apoptotic cell number in the two groups were 23.33 +/- 3.83 and 2.33 +/- 1.21, both of which were statistically significant. CONCLUSION: The direct injection of packaged cells carrying hEN gene is able to inhibit the growth of micro-blood vessels and promote tumor cell apoptosis, which ultimately inhibits the growth of B16 melanoma.

Angiogenesis Inhibitors↗