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Biomedical subjects

Yu Chen

Publications and source records attributed to Yu Chen.

At least 163 records · Page 9Linked to original sources
PubMed2005

[Immune tolerance induced by staphylococcal enterotoxin B for the treatment of rat high-risk corneal transplantation rejection].

OBJECTIVE: To determine the mechanism of staphylococcal enterotoxin B (SEB) induced immune tolerance in the treatment of high-risk corneal transplantation in the rat. METHODS: Fisher 344 rats were used as donors and Lewis rats were used as recipients. Corneal neovascularization was induced by sutures. The rats were divided randomly into five groups in a masked fashion. In the 4 SEB-treated groups, 0.2 ml SEB were intraperitoneally injected before the keratoplasty at concentrations of 25 microg/kg, 50 microg/kg, 75 microg/kg and 100 microg/kg, respectively. The control group received a saline buffer injection intraperitoneally. All allografts were observed and scored for 30 days. Meanwhile, the infiltration of lymphocytes in the allografts, the percentage of lymphocyte subpopulations in the immune organs, the proliferation ability of the lymphocytes and the cytokines in the serum were measured. RESULTS: The SEB at the concentration of 25 microg/kg did not prolong the survival time of the allografts as compared to the control group. With the increase of the concentration of SEB, the survival time in the other three SEB-treated groups were prolonged significantly and the 75 microg/kg group showed the best results. The infiltration of the lymphocytes in the allografts and the percentages of CD4+ and CD8+ lymphocytes in the immune organs in the SEB treated groups were reduced. The proliferation ability of the lymphocytes in SEB treated groups was decreased; the concentration of IL-2 was lower while the concentration of IL-10 was higher in the serum in the SEB treated groups. CONCLUSIONS: SEB at an optimal concentration is effective in inhibiting immune rejection in high-risk corneal transplantation. The mechanism of SEB induced immune tolerance is related to the reduction of the number and the immune tolerance status of the lymphocytes.

Animals↗
PubMed2005

[A cost & benefit management system for investment equipments].

Being aimed at the management of investment equipments, the flow of data has been put forward and the two main modes of data calculating have been established by our relying on No.1 Network of Military Healthy. The real-time management has been realized by the system in regard to eguipments' contact, charges, payouts, interest, payment, forecast and decision-makiing. It has been steadily test-running for more than 10 months in our hospital, and data have been processed exactly and creditably.

Computer Communication Networks↗
PubMed2005

[Killing effect of Ad.TERT-TRAIL on tumor cell lines and its mechanism].

BACKGROUND & OBJECTIVE: Oncolytic adenovirus Ad.TERT, a novel tumor-specific proliferating virus, has been constructed by replacing normal promoter of mild-type adenovirus E1A with promoter of human telomerase reverse transcriptase (hTERT). In vitro and in vivo experiments confirmed that Ad.TERT has antitumor effect. This study was to construct Ad.TERT-TRAIL through inserting apoptosis gene trail into Ad.TERT, and explore its antitumor effect and mechanism. METHODS: Plasmid pZhTERT-trail and adenovirus packaging plasmid pBHGE3 were homologously recombined in HEK293 cells to construct Ad.TERT-TRAIL. Ad.TERT-TRAIL was identified by polymerase chain reaction (PCR), and confirmed by Western blot. Killing effects of Ad.TERT-TRAIL and Ad.TERT on 3 tumor cell lines, SW620, BEL-7404 and Bcap-37, and a normal cell line NHLF were detected by crystal violet dye method or MTT assay. Expression of Caspase-3 in Ad.TERT-TRAIL-, and Ad.TERT-transfected SW620 cells was detected by Western blotu cell apoptosis was detected by flow cytometry (FCM). RESULTS: The 860 bp-length trail gene has been amplified by PCR. Western blot showed trail and E1A only expressed in tumor cells, which confirmed the successful construction of Ad.TERT-TRAIL. Killing effects of Ad.TERT-TRAIL on tumor cells were 10-100 times as strong as that of Ad.TERTu while both of them had little effects on normal cells. After 3 days infection (100 multiple of infection, MOI), survival rate of Ad.TERT-TRAIL-infected SW620 cells was 4%, but that of Ad.TERT-infected SW620 cells was 56%u both viruses had little effects on NHLF cells. Expression of Caspase-3 was higher in Ad.TERT-TRAIL-infected SW620 cells than in Ad.TERT-infected SW620 cells. Apoptosis rate of Ad.TERT-TRAIL-infected SW620 cells was 4 times as high as that of Ad.TERT-infected SW620 cells. CONCLUSIONS: Ad.TERT-TRAIL has much stronger antitumor effect than Ad.TERT. Its effect might relate with inducement effects of trail gene on expression of Caspase-3, and apoptosis of tumor cells.

Adenoviridae↗
PubMed2005

Monitoring the level of serum paraoxonase 1 activity in liver transplantation patients.

BACKGROUND: Paraoxonase 1(PON1) is an ester hydrolase in serum and in the liver. Studies have suggested that PON1 measurement to the current battery of tests may improve the evaluation of chronic liver diseases. The aim of this study was to investigate the clinical significance of monitoring the level of serum PON1 activity in liver transplantation patients. METHODS: A series of biochemical indexes were monitored in preoperative, operative and postoperative serum samples of 17 liver-transplanted patients. The change of serum PON1 level and its relations with other biochemical indexes were analyzed. RESULTS: PON1 was distributed normally in the healthy population and its reference value ranged from 45.5 to 265.8 U/mL. The PON1 level of all patients was lower than that of control group significantly (P<0.001); the level began to elevate continuously 5 minutes after opening of the portal vein and was higher than that 90 minutes after opening of the portal vein (P<0.05). Two days after operation it was still higher than the normal. The levels of serum ALT and AST elevated more significantly after opening of the portal vein than before operation and they were higher than the normal values till 2 days after the operation. CONCLUSIONS: The level of PON1 in serum may be taken as one of the effective indexes to assess whether the implant is alive and to monitor liver function of the patient together with other tests.

Adult↗
PubMed2005

Effects of Salvia miltiorrhiza on intestinal microflora in rats with ischemia/reperfusion liver injury.

BACKGROUND: Hepatic ischemia/reperfusion injury may induce intestinal microflora imbalance. Salvia miltiorrhiza is effective in promoting blood circulation and counteracting peroxidation in tissues. The aim of the present study was to determine the effects of Salvia miltiorrhiza on intestinal microflora, endotoxemia, and bacterial translocation in rats with hepatic I/R injury. METHODS: Sprague-Dawley rats in specific pathogen free grade were divided into 3 groups: group I(n=6) for sham operation; groups II(n=10) and III(n=7) for liver ischemia for 20 minutes and reperfusion for 22 hours. Group III was also pretreated with 4 ml/day of Salvia miltiorrhiza solution (250 mg/kg) by daily gavage for 7 days. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA) and superoxide dismutase(SOD) in liver tissues, serum endotoxin, intestinal bacterial counts, intestinal mucosal histology and bacterial translocation were studied. RESULTS: The levels of ALT, AST, plasma endotoxin and MDA in liver tissues were decreased more markedly in group III (57.57+/-18.08 U/L, 147.57+/-40.84 U/L, 0.42+/-0.144 EU/ml and 0.52+/-0.19 nmol/mg-prot respectively) in group II(122.8+/-80.12 U/L, 295.9+/-216.92 U/L, 0.80+/-0.262 EU/ml and 0.72+/-0.12 nmol/mg-prot; P<0.05-0.01 respectively). Liver SOD activity was increased more significantly in group III (318.47+/-64.62 U/mg-prot) than in group II(240.76+/-63.67 U/mg-prot, P<0.05). The counts of Bifidobacteria and Bacteroides increased more significantly in group III than in group II, but were similar to those in group I. Bacterial translocation to the kidney in group II was 50%(5/10), whereas no bacterial translocation to the kidney occurred in the other two groups (P<0.01). Ileal mucosal structure was markedly ameliorated in group III as compared with group II. CONCLUSIONS: Salviae miltiorrhiza could partially restore intestinal microflora balance, improve intestinal mucosal integrity, and reduce bacterial translocation and plasma endotoxin in rats with hepatic ischemia/reperfusion injury.

Animals↗
PubMed2005

[Antitumor effects of ring-closed and ring-opened hydroxycamptothecin on oral squamous carcinoma cell line Tca8113].

BACKGROUND & OBJECTIVE: The antitumor effect of hydroxycamptothecin (HCPT) closely relates with its lactone form (including ring-closed form and ring-opened form), but the antitumor effects of ring-closed HCPT (C-HCPT) and ring-opened HCPT (O-HCPT) remain controversial. Researches have showed that O-HCPT has obvious in vitro and in vivo antitumor effects on oral squamous cell carcinoma. This study was to compare the antitumor effects of C-HCPT and O-HCPT on oral squamous carcinoma cell line Tca8113, and explore the mechanisms. METHODS: Tca8113 cells and its xenografts in BALB/C nude mice were treated with C-HCPT and O-HCPT. The cytotoxicity of HCPT was measured by MTT assay. Cell cycle was detected by flow cytometry. The growth state of Tca8113 cells xenografts was observedû the tumor doubling time and inhibition rate were calculated. The concentration of total HCPT in plasma and tumor tissue was quantitated by high-performance liquid chromatography (HPLC); the pharmacokinetic parameters were estimated. RESULTS: C-HCPT and O-HCPT showed similar cytotoxicity effects on Tca8113 cells in vitro. Low concentration of HCPT (< 1 micromol/L) arrested cell cycle of Tca8113 cells at S phase and G(2)/M phase; high concentration of HCPT (100 micromol/L) obviously induced apoptosis of Tca8113 cells. Compared with control group, the xenografts of HCPT-treated group grew slowly, and the tumor doubling time was prolonged. The tumor inhibition rates were 69.6% (3 mg/kg of O-HCPT), 65.0% (3 mg/kg of C-HCPT), and 74.1% (10 mg/kg of O-HCPT), respectively. The plasma AUC was 2.66 microg . h . ml(-1) for C-HCPT (10 mg/kg) and 0.42 microg . h . ml(-1) for O-HCPT (10 mg/kg). HCPT could be detected in tumor tissue. No obvious toxicity was observed in 3 mg/kg of HCPT group; obvious gastrointestinal reaction was observed in 10 mg/kg of O-HCPT group; all nude mice in 10 mg/kg of C-HCPT group died 2 days after treatment. CONCLUSIONS: Both C-HCPT and O-HCPT have strong in vitro and in vivo cytotoxic effects on Tca8113 cells, which relate to cell cycle arrest and cell apoptosis inducement. Cytotoxicity of C-HCPT is more severe than that of O-HCPT.

Animals↗
PubMed2005

[Characteristics of staphylococcal enterotoxin B (SEB)-induced anergy in transplantation of allogeneic bone marrow cells].

AIM: To investigate the characteristics of the SEB-induced anergy in transplantation of allogeneic bone marrow cells. METHODS: C57BL/J (recipients) and BALB/c (donors) mice were used in this study. The recipients were irradiated with 6.0Gy (60)Co-gamma ray followed by transplantation of allogeneic bone marrow cells (6x10(7)). The recipients treated with (60)Co-gamma-ray were then divided into 3 groups; group 1 treated with (60)Co-gamma-ray (RI control group), and group 2 (transplantation control group) and group 3 (SEB experimental group) received saline or 60 mug SEB after the transplantation of bone marrow cells. T cell subtypes and expression of MHC molecules were detected by flow cytometry. Proliferation of lymphocytes in response to ConA and allogeneic antigen were examined by MLR. RESULTS: (1) The recipients treated with and without SEB survived for at least 180 days and became chimeric with white hair color (the donors' color). (2) SEB inhibited proliferation of lymphocytes in the recipients in response to ConA but not to allogeneic antigen as compared with that in the Group 1 and Group 2 mice. (3) The CD4(+) T but not CD8(+) T cells in the recipients treated with SEB were decreased from day 30 to day 60 after transplantation. (4) With the treatment of SEB, frequency of CD3(+)/NK1.1(+) NKT cells was increased to 5.71% on day 180. In the recipients, the expression of donor's MHC H-2K(d) were enhanced 80.95% and of expression self MHC H-2K(b) was 1.45% only. CONCLUSION: SEB can induce a stronger anergy than that induced by irradiation. SEB-induced anergy is related with the reduction of CD4(+) T cells and increase of CD3(+)/NK1.1(+) NKT cells at the early phase of transplantation. T cells showed specific down-regulation in this study.

Animals↗
PubMed2005

[Relationship of the disturbed balance between matrix metalloproteinases and their tissue inhibitors and the invasion of malignant salivary gland tumours].

OBJECTIVE: To detect protein expression of MMPs and TIMPs in various salivary gland neoplasms and to investigate their roles in invasion and metastasis of the malignant salivary gland tumors. METHODS: Immunohistochemistry and Gelatin zymography analyses for MMP-2, MMP-9, MT1-MMP, TIMP-1 and TIMP-2 were performed in 26 malignant and 28 benign salivary gland tumors. RESULTS: The expression of MMP-2 and MMP-9 was significantly higher in carcinomas than in adenomas (P < 0.05). The MMP-2/TIMP-1 and MMP-2/TIMP-2 was also significantly higher in carcinomas than in adenomas (P < 0.05). There was a cooperated effect among MMP-2, MT1-MMP and TIMP-2. The expression of active MMP-2, proMMP-9 and active MMP-9 was significantly higher in malignant tumors than in benign tumors (P < 0.05). CONCLUSION: MMP-2 and MMP-9 may play important roles in invasion of malignant salivary gland tumors. A disturbed balance between MMP-2, MMP-9, TIMP-1 and TIMP-2 in malignant salivary gland tumors was detected. It was the absolute increase of MMP-2 and MMP-9 to induce the unbalance.

Enzyme Precursors↗
PubMed2005

[Establishment of human endothelial-overexpressed lipopolysaccharide-associated factor 1 compelling expression model and its effects on the proliferation of ECV304 cells].

OBJECTIVE: To design and construct the inducible expression vector of endothelial-overexpressed lipopolysaccharide-associated factor 1 (EOLA1), in order to establish EOLA1 compelling expression model, and to observe the effects of EOLA1 compelling expression on the proliferation of ECV304 cells. METHODS: Inducible overexpression vector pOPRSV I-EOLA1 was constructed by amplifying the open reading fragment of EOLA1 and subcloning it into the Not I site and Xho I site of pOPRSV I vector. After sequencing, the pOPRSV I-EOLA1 recombinant vector and pCMVLac I vector were co-transfected into ECV304 cells. The cells resistant to G418 and hygromycin were screened by G418 and hygromycin, so that stable transfected cell strain was obtained. The growth curve of cells with or without isopropyl-beta-D-thiogalactoside (IPTG) induction were graphed with cell counting. RESULTS: The inducible overexpressed EOLA1 vector was constructed successfully. The proliferation of the cells with EOLA1 compelling expression after induction of IPTG (44 +/- 17) x 10(4) was significantly higher than that without IPTG induction (27 +/- 11) x 10(4), (P < 0.01). CONCLUSION: Compelling expression of EOLA1 protein can enhance the proliferation of ECV304 cell.

Cell Line↗
PubMed2005

[Identification and characterization of a novel gene EOLA1 stimulating ECV304 cell proliferation].

OBJECTIVE: To amplify the full-length cDNA and characterize the structure and biological function of a novel expression sequence tag ST55 (GenBank Accession No. BM121646). METHODS: Rapid amplification of cDNA ends was used to clone the full-length of cDNA of ST55 in this study. Then, its tissue distribution was checked by Northern blots, and the associated protein was screened by GAL 4-based yeast two-hybrid. The effect of stable transfection of the cDNA on cell proliferation was evaluated in ECV304 cells. RESULTS: A full-length 1404 bp cDNA was cloned, and it was accepted as a novel human mRNA by GenBank (No. AY074889), named endothelial-overexpressed lipopolysaccharide-associated factor 1 (EOLA1). Bioinformatic analysis found that the EOLA1 encoded 158 amino acids, 17.89 kDa protein, and mapped to chromosome Xq27.4 with 5 exons. EOLA1 expressed in different human normal tissues and cancer cell lines. Using the EOLA1 cDNA as bait, we performed a yeast two-hybrid screening of a human liver cDNA library and identified metallothionein 2A (MT2A) as associated protein. The interaction between EOLA1 and MT2A was confirmed by co-immunoprecipitation experiments. Stable transfection of EOLA1 was noted to stimulate ECV304 cell proliferation (P < 0.05). CONCLUSION: The findings suggest that EOLA1 is a novel gene and the interaction of EOLA1 and MT2A may play an important role in cell protection in inflammation reaction.

Amino Acid Sequence↗
PubMed2005

[Complete HBV DNA clone and sequence from serum samples of severe hepatitis B patients].

OBJECTIVE: To study the association between hepatitis B virus (HBV) mutants and the pathogenesis of severe hepatitis B by full-length HBV genome. METHODS: Serum samples from 10 severe hepatitis B patients were collected in our hospital. Serum HBV DNAs were extracted using DNA mini Kit, and amplified by LA Taq DNA polymerase to yield full-length HBV DNA. PCR products were isolated and cloned into vector pUCm-T, then transfected into DH-5 alpha cells. Positive clones were selected and checked by digestion, and full-length HBV DNAs were sequenced. RESULTS: 4 cases were cloned into vector pUCm-T successfully and completed the full-length sequencing. Among them, 3 cases had a G to A mutation at nucleotide 1896 in pre-C region and 1 had a double mutation of T1762-A1764 in the core promoter region. Some amino acid changes occurred within the known CTL, B or T cell epitopes of the PrS2 and C regions. CONCLUSIONS: This method could serve to study the relationship between HBV genome and the pathogenesis of severe hepatitis B.

Adult↗
PubMed2005

Gene heterogeneity of hepatitis B virus isolates from patients with severe hepatitis B.

BACKGROUND: The pathogenesis of severe hepatitis B remains unknown. Reports have indicated that hepatitis B virus (HBV) mutations are important factors in the pathogenesis of this disease. This study was to investigate the genetic heterogeneity of HBV strains from serum samples of patients with fulminant hepatitis B. METHODS: Full-length HBV genomes from 4 patients with severe hepatitis B were cloned and sequenced to observe mutations in every open reading-frame (ORF). Serum samples of another 25 patients with severe hepatitis B, 30 patients with chronic hepatitis B, and 25 HBV carriers were collected for sequencing and comparison of mutations in preS2, preC and core promoter regions. RESULTS: Of 4 HBV full-length genome sequences, 3 had a G to A mutation at nucleotide A1896 in the preC region and 1 had double mutations of T1762-A1764 in the core promoter region. The 4 sequences showed mutations in the known B or T cell epitopes of the preS2 and C regions. For the other 3 groups, more mutations were seen in the preS2 region in the HBV isolates from the patients with severe hepatitis B than those from the patients with chronic hepatitis B and HBV carriers (P<0.01). There was a significant difference of mutations in the T cell epitope region of preS2 between the patients with severe hepatitis B and those with chronic hepatitis B or HBV carriers (P<0.01). In the preC and core promoter regions, the mutation frequencies of T1653 and C1753 were 48.0% and 24.0% respectively in the patients with severe hepatitis B, but none of these mutations were observed in the patients with chronic hepatitis B group or HBV carriers (P<0.01). The mutation frequency of T1762-A1764 was 76.0% in the patients with severe hepatitis B, 40.0% in the patients with chronic hepatitis B (P<0.01), and 16.0% in the HBV carriers (P<0.01). There was a significant difference in A1896 mutation between the patients with severe hepatitis B and the patients with chronic hepatitis B (P<0.05) or the HBV carriers (P<0.05). CONCLUSION: Our observations suggest that the accumulation and persistence of high frequency mutations or complex mutations may be associated with the development and deterioration of HBV infection.

Adult↗
PubMed2005

[Protective effect of reduced glutathione on multiple organ function in patient with acute pancreatitis].

OBJECTIVE: To study the protective effect of reduced glutathione (GSH) on multiple organ function in patient with acute pancreatitis. METHODS: A total of 45 patients with acute pancreatitis was randomly divided into two groups, 22 patients were given GSH in a dose of 1.2 g/d through intravenous drip for 7 days as GSH group, and 23 patients were not given GSH to serve as control group. The same treatment was given to both groups other than GSH. Plasma contents of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) and biochemistry indexes were determined. RESULTS: After the treatment, the levels of TNF-alpha and IL-6 were significantly decreased in both groups (all P<0.05). The levels of TNF-alpha and IL-6 were decreased much more obviously in GSH group compared with those in control group (P<0.05). Plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (Cr), blood urea nitrogen (BUN), lactate dehydrogenase (LDH), creatine kinase (CK), and MB isoenzyme of creatine kinase (CK-MB) were significantly decreased in both treatment groups, but the decrease of all these indexes was more marked in GSH group (P<0.05). CONCLUSION: The results suggest that GSH has beneficial effects in protecting visceral organ function in patients with acute pancreatitis.

Acute Disease↗
PubMed2005

[Compare the differences between automatic analysis and manual analysis of apnea events in polysomnogram].

OBJECTIVE: To investigate whether there are differences on the diagnose of sleep apnea hypopnea syndrome between automatic analysis and manual analysis of respiration events in polysomnogram. METHOD: Sixty snoring human was selected randomly and monitored separately by sleep monitor in seven hour at night, sleep monitor would produce a poly sonogram, firstly polysomnogram was analysis by the software of sleep monitor and then by the manual operation. Finally data were processed by statistical analysis. RESULT: There were significant differences between automatic analysis and manual analysis of polysomnogram on apnea hypopnea index,apnea index, hypopnea index and long apnea. Data of manual analysis were more consistent with clinic symptoms of patients than automatic analysis. CONCLUSION: The result of automatic analysis of polysomnogram had a deviation to the diagnosis of pathogenetic, in order to improve the accuracy of clinic diagnosis, polysomnogram should be analysis by manual operation generally.

Adult↗