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Kun Li

Publications and source records attributed to Kun Li.

43 records · Page 3Linked to original sources
PubMed2003

Samarium and manganese-doped lead titanate ceramic fiber/epoxy 1-3 composite for high-frequency transducer application.

Samarium- (Sm) and manganese- (Mn) doped lead titanate ceramic fibers with a diameter of 35 microm were prepared using a sol-gel method. The X-ray diffraction pattern shows that the fibers have a pure perovskite structure. The 1-3 composite disks with a thickness of 31-41 microm and with ceramic volume fraction of approximately 0.68 have been prepared using the samarium and manganese doped lead titanate (PSmT) fibers. The resonance characteristics of the poled composite disks were measured. A focused transducer was fabricated using a concave 1-3 composite disk with nonuniform thickness in order to enhance its bandwidth. The insertion loss (IL), pulse-echo response and frequency spectrum of the composite transducer were measured. The center frequency of the transducer was approximately 31 MHz with a -3 dB bandwidth of approximately 123% and a low IL of 29.3 dB.

Ceramics↗
PubMed2003

[Enhancement of human papillomavirus type 16E6E7 vaccine-induced specific immune response by coimmunization with B7-1 co-stimulatory gene].

OBJECTIVE: To develop a therapeutic vaccine against human tumors associated with human papillomavirus type 16E6E7 (HPV16E6E7) which is modified from a Chinese patient of the cervical cancer which possessing the antigenicity and no transforming activity, and explore more active vaccine for inducing cellular immunity with mouse co-stimulatory molecular B7-1 gene. METHODS: The modified E6E7 gene expression plasmid pVR1012-fmE6E7 was constructed and transfected Cos-7 cells, and the E7 protein specific expression was testified by immunofluorescence assay. C57BL/6 mice were immunized intramuscularly with pVR1012-fmE6E7 alone or in combination with B7-1 gene expression plasmid (pcDNA3.1-B7-1). The activity of cytotoxic T lymphocytes (CTLs) was analyzed with 51Cr specific release assay and the specific antibody in sera was analyzed by indirect ELISA. HPV16 positive C57BL/6 tumor cells C3 were inoculated subcutaneously in the vaccinated mice to assay the growth of transplanted tumors. RESULTS: The specific CTLs and antibody from immunized mice were induced efficaciously by the E6E7 gene immunization, and co-administration of B7-1 gene could significantly enhanced the CTLs immune responses of fmE6E7, and protected 33% immunized mice against C3 tumor cells challenge. In contrast, all the mice immunized only with fmE6E7 gene developed transplanted tumors after C3 cells challenge. There was no difference in E7 specific antibody responses between mice immunized with the E6E7 gene only and co-administration with B7-1 gene. CONCLUSIONS: The modified E6E7 gene can be used as target gene for developing DNA vaccine, and B7-1 gene may represent an attractive adjuvant for enhancement of the specific cellular immune responses.

Animals↗
PubMed2003

[Karyotype analysis of Picris davurica chromosome].

OBJECTIVE: To systematically study Picris davurica Fisch chromosome karyotype. METHODS: Sections combined with micrograph were used to analyse chromosome. RESULTS: Chromosome number of normal diploid was 2n = 10, karyotype formula was K (2n) = 10 = 2 m + 8 sm, the relative length was 2n = 10 = 2 L + 2 M2 + 4 M1 + 2 S, which belonged to "3 A" type. The total length of chromosome groups was 12.51 microns, the total length of long arms was 8.36 microns, the AS. K% was 66.83%. The total volume of chromosome was 11.71 microns3. CONCLUSION: Picris davurica chromosome number and morphological character were clear.

Asteraceae↗
PubMed2003

[Effect of human cytomegalovirus on hematopoietic system].

OBJECTIVE: To investigate the mechanism and the suppression effect of human cytomegalovirus (HCMV) on hematopoietic system. METHODS: Semi-solid culture system was used to observe the effect of HCMV AD169 strain on colony forming unit granulocyte/macrophage (CFU-GM), CFU-erythroid (CFU-E), CFU-multipotent (CFU-Mix) and CFU-megakaryocyte (CFU-MK) growth. The techniques of in situ polymerase chain reaction (IS-PCR) and polymerase chain reaction (PCR) were used to demonstrate the existence of HCMV DNA in the colony cells of cultured CFU-GM, CFU-Mix, CFU-MK and CFU-E, respectively. The immediate early antigen (IEA) mRNA in CFU-MK and late antigen (LA) mRNA in CFU-E were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). HCMV early protein P52 was detected with immunohistochemical technique. RESULTS: HCMV AD169 suppressed the differentiation and proliferation of CFU-GM, CFU-E, CFU-Mix and CFU-MK in vitro significantly (P < 0.05). The suppression was dose-dependent. HCMV DNA was successfully detected in CFU-GM, CFU-Mix, CFU-MK colony cells from viral infection groups by IS-PCR, and was detected in CFU-E by PCR, while it was negative in blank control or mock control groups. CFU-MK colony cells expressed HCMV IEA mRNA with the size of 340 bp in virus infection groups of 10(3) plague forming unit (PFU), 10(4) PFU and 10(5) PFU, respectively. The HCMV LA mRNA was detected by RT-PCR and was 263 bp long in positive control group of HCMV-infected human embryonic fibroblasts. The expression of HCMV LA mRNA in CFU-E was negative. The early protein P52 of HCMV in 10(4) PFU group was also identified by immunohistochemical staining. CONCLUSION: HCMV AD169 strains inhibited the differentiation and proliferation of CFU-GM, CFU-E, CFU-Mix and CFU-MK by the infection of the hematopoietic progenitors. HCMV might cause the suppression of hematopoiesis by direct infection, which is thought to be one of the reasons of HCMV infection associated with thrombocytopenia, neutropenia and anemia.

Colony-Forming Units Assay↗
PubMed2002

Tolerance limit of rats to normothermic hepatic inflow occlusion under portal blood bypass.

OBJECTIVE: To evaluate the tolerance limit of rats to normothermic hepatic inflow occlusion under portal blood bypass. METHODS: A new rat model of normothermic hepatic inflow occlusion under portal blood bypass was established by clamping temporarily the pedicles of all liver lobes while the caudal lobe was kept as a passage of the portal blood flow. After hepatic blood flow restored, the caudal lobe was cut off. On the 7th postoperative day, survival rate, hepatic morphological changes, and the severity and reversibility of the injured energy metabolism of the liver were investigated. RESULTS: All rats that had been subjected to 30, 60 and 90 minutes of hepatic inflow occlusion under portal blood bypass survived on the 7th postoperative day. ischemia-reperfusion injury of the liver was reversible and compensatory in rats with hepatic inflow occlusion within 90 minutes. However, the survival rates of rats with 100, 110 and 120 minutes of hepatic inflow occlusion were 50%, 30% and 20% respectively. Liver injury of rats with 120 minutes of hepatic inflow occlusion was severe and Irreversible. CONCLUSIONS: The tolerance limit of rats to normothermic hepatic inflow occlusion is enhanced significantly under portal blood bypass and the upper limit is 90 minutes.

Adenosine Triphosphate↗
PubMed1998

Effect of aging on cytoskeleton system of Kupffer cell and its phagocytic capacity.

AIM:To investigate the age-related alterations of cytoskeleton system in liver Kupffer cell and their relation to the changed phagocytic function.METHODS: The phagocytic function of Kupffer cells from rats of various ages (6mo, 12mo,18mo and 24mo) were quantitatively evaluated by phagocytosis of polystyrene beads. The actin distribution and measurement of Kupffer cell were determined by a phalloidin-TRITC method; and the myosin and vimentin distribution and measurement with indirect immunochemical staining.RESULTS: Aging resulted in significant alterations of actin, myosin and vimentin distributions and reductions in Kupffer cell; the 3 cytoskeleton components of 24-mo-old Kupffer cell were significantly decreased to 68.0%, 84.9% and 75.5%, respectively of these of 6-mo-old Kupffer cell(P < 0.01,0.01 and 0.01). And these decreases had significant positive relations with the damaged phagocytosis of the aged Kupffer cell.gammavalues were 0.96(P < 0.05), 0.99(P < 0.01) and 0.95 (P < 0.05) respectively.CONCLUSION: The cytos-keleton system of the aged Kupffer cell presents an evident state of senescence, which may be an important mechanism of decreased phagocytosis of the aged Kupffer cell.

Journal Article↗