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Biomedical subjects

T Liu

Publications and source records attributed to T Liu.

At least 235 records · Page 13Linked to original sources
PubMed1999

[Effect of shenshuaining on proliferation and autocrine interleukin-1 secretion of human mesangial cells].

OBJECTIVE: To explore the effect of Shenshuaining (SSN), on the proliferation of human mesangial cells (HMC) and the autocrine secretion of interleukin-1 (IL-1). METHODS: SSN, a preparation of Chinese herbal drug having actions of Qi supplementing, origin consolidation, blood stasis resolving and turbid substance removing, medicated serum of animal was extracted by pharmacologic method and its effect on proliferation and autocrine IL-1 secretion of HMC was observed. RESULTS: SSN could inhibit the proliferation and IL-1 autocrine secretion of HMC, and the inhibition was dose-dependent. CONCLUSION: Mesangial cell is the important target cell for action of SSN, the inhibition on HMC may be one of the mechanisms of SSN in prevention and treatment of chronic renal failure.

Animals↗
PubMed1999

[Effect of preoperative chemotherapy on apoptosis and tissues of pancreatic adenocarcinoma].

OBJECTIVE: To investigate the apoptosis and tissues change of pancreatic adenocarcinoma with or without preoperative chemotherapy and discuss the effect of preoperative regional chemotherapy on pancreatic adenocarcinoma cell. METHODS: Using the method of TUNEL and microscope, we determined the apoptosis of tumor cells and tissues changes in 30 pancreatic adenocarcinoma patients with or without preoperative chemotherapy. RESULTS: The ratio of apoptosis was much higher in the preoperatively treated group than in the untreated group (44.87 +/- 27.78) and (3.6 +/- 3.76)/HP, (P < 0.01). The ratio of apoptosis was related to the tissue type of pancreatic adenocarcinoma. The ratio of apoptosis in the highly differentiated adenocarcinoma group was much higher than that in the middle or low differentiated adenocarcinoma group (P < 0.05, P < 0.01). The inflammatory reaction and the proliferous intima of vessels were more obvious in the preoperatively treated group than in the untreated group (P < 0.05, P < 0.01). CONCLUSIONS: Preoperative regional chemotherapy can effectively inhibit pancreatic adenocarcinoma by inducing the apoptosis of tumor cells.

Adenocarcinoma↗
PubMed1999

[Relationship between GSTM1 genotype and susceptibility to senile cataract].

OBJECTIVE: To study the relationship between the glutathione s-transferase gene deletion and cataract formation. METHODS: Blood cells of total of 77 cases with senile cataract and 76 controls were detected for GSTM1 gene, and the subcapsular epithelial cells of 22 cataract lenses were also detected for GSTM1 gene. RESULTS: The GSTM1 gene deletion rate in cataract group was 53.25% and that in the control group was 46.05%, they being not significantly different statistically (chi(2) = 0.750, P > 0.05, OR = 0.75). GSTM1 gene deletion rate in the subcapsular epithelial cells of 20 cases was basically consistent with that in blood cells. CONCLUSION: GSTM1 gene deletion is not related to senile cataract formation.

Aged↗
PubMed1999

[Evaluation of DNA recombinant chitinase fusion protein antigens in serological diagnosis for filariasis].

OBJECTIVE: To evaluate DNA-recombinant chitinase fusion protein antigen in serodiagnosis for Bancroft's filariasis in jirds rats with microfilaremia and normal jirds rats with ELISA, and its prospect in the market to be spread. METHODS: Oligonucleotide was synthesized with filaria monoclonal antibody (Mf(1))-recognized microfilaria chitinase fusion protein and basic primer recognized by original clonal nucleosides, and amplified with polymerase chain reaction (PCR). PCR products were expressed in Pmal-c vector and purified by affinity chromatography. Experimental animals were inoculated with chitinase fusion protein antigen and infected with larval stage filaria Brugia malayi, respectively. Functional protein molecule of chitinase antigen was analyzed with SDS-PAGE and western blot. Serum level of specific antibody to chitinase antigen was determined by ELISA, and compared with that to microfilaria xt antigen (Mf-xt). RESULTS: Specific function protein molecule of the above-mentioned chitinase antigen has been identified as 69,000. Serum antibody against chitinase antigen was 100% positive for jirds and patients with microfilaremia, but, that against Mf-xt only 80% positive. Serum antibody against chitinase antigen was negative for all normal jirds and normal persons, but that against Mf-xt had 5% false positive in normal serum. For those with microfilaremia from non-filariasis-prevalent areas, false sero-positivity was 5% and 20% with chitinase antigen and Mf-xt, respectively. CONCLUSION: ELISA with DNA recombinant fusion protein antigen is a sensitive and specific method in serological diagnosis and surveillance for filariasis, with simple, easy and convenient manipulation. It can be used in field serologic surveillance and diagnosis for filariasis during the late phase in control of filariasis and can be spread in good prospects.

Animals↗
PubMed1999

[Transformation of human bronchial epithelium by EB virus gene LMP1 and EBNA2].

OBJECTIVE: To observe Epstein-Barr virus (EBV)-dependent transformation of human bronchial epithelium. METHODS: Eukaryotic expression plasmide pBS-LMP-Hyg and pSG5-EBNA2-Hyg were transfected into immortalized human bronchial epithelium cell line TR. RESULTS: In situ hybridization and Western blot confirmed EBNA2 and LMP1 expression in one hygromycine B resistant cell clone TR/LMP1-EBNA2. Growth curve and MTT value showed that transformed cells grew faster. Soft agar plating rate of TR/LMP1-EBNA2 was 50.1per thousand, 68.2per thousand, empty vector PBs-Hyg transfected cell strain TR/Hyg 2.0per thousand, 3.0per thousand, TR 11.0per thousand, 0.7per thousand. CONCLUSION: Expression of both LMP1 and EBNA2 led to decreased anchorage dependence and increased proliferation rate of TR, thereby further transformed immortalized human bronchial epithelium. Our results suggest that EBV may play a role in genesis of lung cancer.

Animals↗
PubMed1999

[The establishment of a human pancreatic mixed ductal-endocrine carcinoma cell line].

OBJECTIVE: Establishment of a human pancreatic mixed ductal-endocrine carcinoma cell line. METHODS: A specimen of this type of cancer was obtained from a male patient at the head of pancreas. The tumor tissue was minced into pieces and inoculated subcutaneously in nude mice. With two successive subcutaneous implants, a piece of tumor tissue taken from the 2(nd) implanted neoplasm of a nude mouse was minced into minute tissue masses and inoculated in a media containing 10% fetal bovine serum. RESULTS: Currently, it has been passed to the 55(th) passage. Cells of this cell line (PC-EN) kept simultaneously the morphologic patterns of a pancreatic ductal and endocrine tumor which were verified by histochemistry and immunohistochemistry assays. Some of the PC-EN cells showed presence of neuroendocrine granules by electron microscopy. The growth rate of this cell line was relatively low. Kakryotype analysis showed two cell populations with its major mode of chromosomes numbers as 48 in one, and 56 in the other. Study on K-ras gene demonstrated that PC-EN harbored a mutated codon 12. Several gastrointestinal hormones and CEA were detected in PC-EN cells and in the supra-cultured medium using radioimmunoassay. CONCLUSIONS: The cellular and molecular biologic characteristics of PC-EN cells illustrated that this cell line preserved the morphology of a pancreatic ductal and endocrine tumor and possessed a special growth property, chromosome karyotype, and mutation of Ki-ras gene, but also showed a biologic exocrine and endocrine functions of the pancreas. The establishment of PC-EN cell line will provide a useful model in vitro for further investigating the cellular and molecular biology of exocrine and endocrine tumors of the pancreas.

Aneuploidy↗
PubMed1999

[The mechanism of bystander effect in herpes simplex virus thymidine kinase/ganciclovir-mediated gene therapy].

OBJECTIVE: To study the mechanism of bystander effect in herpes simplex virus thymidine kinase (HSV-TK)/Ganciclovir (GCV)-mediated gene therapy. METHODS: Recombinant retroviral vectors expressing HSV-TK and beta-Galactosidase (Lac Z) genes were constructed and transferred into pancreatic carcinoma cell line respectively. Cell counting was used to detect the growth inhibition rate of HSV-TK-transduced cells in presence of GCV. Taking Lac Z-transduced cells as bystander cells, the bystander effect was detected by MTT method, and its mechanism was studied by the experiments of supernatant shifting, Verapamil inhibition and ultrastructural observation. RESULTS: The growth inhibition rate of the HSV-TK-transduced cells in the presence of GCV was 92.1%, which was obviously 4.9% and 3.2% higher than of the non-and control vector-transduced cells. Mixed cells containing only 10% of HSV-TK-transduced cells showed 39.0% reduction of the proliferation, which meant there was an obvious bystander effect in the system. However this effect disappeared when transferring GCV-containing supernatant of HSV-TK-transduced cells to the parent cells and could be reduced significantly when verapamil was added in the medium, indicating that this bystander effect requires cell-cell contact. Gap junctions were observed existing between PC-2 cells by electron microscopy. CONCLUSION: The bystander effect in HSV-TK/GCV-mediated gene therapy occurs by transfer of GCV metabolite from cell to cell through gap junction.

Antiviral Agents↗
PubMed1999

[Partial splenic embolotherapy in hypersplenism with portal hypertension].

Twenty-one cases of hypersplenism with portal hypertension were treated with partial splenic embolization. The results were that spleens were shrink and the condition of white blood cells, platelets, and prothrombin time of the patients were obviously improved. We conclude that the appropriate antibiotics, superselective catheterization, and the management of postoperation are necessary; the volume of embolism is limited from 50% to 75% of the spleen. This technique has the features of steady therapeutic effect, safety, and microtrauma.

Embolization, Therapeutic↗
PubMed1999

[A study on the biological properties of fimbriae of Actinomyces viscosus. I. The preparation and determination of fimbriae of A. viscosus].

OBJECTIVE: To build up the methods to prepare and determine the fimbriae of A. viscosus. METHODS: Type 1 and 2 fimbriae were prepared from A. viscosus 5519 and 5951 respectively. Fimbriae were isolated from bacteria cells by mechanical shaking, obtained by collecting the supernatant after centrifugation, and purified by ammonium sulfate precipitations and gel filtration. RESULTS: Electron microscope showed that fimbriae existed in the preparations. The immunological reaction between the fimbriae preparations and specific antibodies against fimbriae attested that they were type 1 or type 2 fimbriae. CONCLUSION: The present study become a foundation for further study on the biological properties of fimbriae of A. viscosus.

Actinomyces viscosus↗
PubMed1999

[Separation and selection of salivary adhesion receptors of Streptococcus mutans to tooth surface].

OBJECTIVE: To select and purify salivary receptors of Streptococcus mutans from experimental salivary acquired pellicle. METHODS: Experimental salivary acquired pellicle (SAP) was performed by coating hydroxyapatite (HA) with whole saliva. Then SAP was washed from HA by 1 mol/L NaCl and 0.5 mol/L phosphate buffer sequentially. The proteins were further separated by chromatography of Sephadex G75 and DEAE-Sephadex A25. Receptors of Streptococcus mutans were selected by bacterial adhesion test and competitive inhibition adhesion test. Identification was performed by PAGE, SDS-PAGE, IP-PAGE and detection of amylase activity and inmunodifusion test. RESULTS: IgA degraded fragments, a protein of 13 kD and amylases were the receptors of S. mutans. The first two only promote the adhesion but the amylases can both promote and inhibit S. mutans adhesion. CONCLUSION: The adhesion of S. mutans to tooth surface is a result of interaction between adhesins of S. mutans and multiple salivary receptors.

Adhesins, Bacterial↗
PubMed1999

[Construction of Streptococcus mutans surface protein antigen eukaryotic expression vector pcDNA3-PAc. I. Extraction and purification of plasmid DNA pPC41 and pcDNA3].

OBJECTIVE: To Extract and purify plasmid DNA pPC41 and pcDNA3. METHODS: Bacteria were collected and lyzed by the alkaline lysis method. The plasmid pPC41 carrying structural gene pac and clone expression vector pcDNA3 were extracted and purified from E. coli clone by the polyethylene glycol precipitating method, the electroelution into dialysis bags method, the low melting-temperature agarose gel and glass fiber column chromatography. The concentration, purity and molecular weight were determined by spectrophotometry, restriction enzyme and agarose gel electrophoresis. RESULTS: The concentration of plasmid DNA of this experiment in general was 0.12-0.24 g/L, and A260/A280 of the polyethylene glycol precipitating method, the electroelution into dialysis bags method, the low metling-temperature agrose gel and glass fiber column chromatography were respectively 1.9, 2.2, 2.2 and 2.6. Molecular weight of pPC41 and pcDNA3 was respectively 10.6 kb and 5.4 kb. CONCLUSION: The four methods can obtain pure plasmid DNA. Purity of plasmid DNA obtained by glass fiber column chromatography method is the highest in the four methods. Glass fiber column chromatography is one of the effective methods getting highly purified plasmid DNA.

Antigens, Surface↗
PubMed1999

[Construction of Streptococcus mutans surface protein antigen eukaryotic expression vector pcDNA3-PAc. II. Testified efficiency of repeated using glass fiber chromatographic column].

OBJECTIVE: To explore one method getting highly purified plasmid DNA and costing low. METHODS: According to principle of extraction and purification plasmid DNA of glass fiber chromatographic column, its operation sequence was improved so that disposable glass fiber chromatographic column could be used repeatedly. The concentration and purity of plasmid DNA obtained by 12 times repeated using glass fiber chromatographic column were determined by spectrophotometry. Moreover, Those plasmid DNA obtained were tested by restriction enzyme and agarose gel electrophoresis, Ligation in vitro and transformation test. RESULTS: 12 times repeated use of glass fiber chromatographic column made no significant difference to the concentration and purity of obtained plasmid DNA (P < 0.05), and plasmid DNA was completely digested by restriction enzyme. The digested fragments were well ligated together by the action of T4 DNA Ligase in ATP ligating buffer in vitro and ligated DNA was well transformed into E. coli. CONCLUSION: Repeated use glass fiber chromatographic column can obtain a lot of highly purified plasmid DNA and cost is low. Digestion, ligation and transformation of those plasmid DNA are not affected. The results may be significant in molecular cloning and study of gene vaccination.

Antigens, Surface↗
PubMed1999

[A study on biological properties of fimbriae of Actinomyces viscosus. II. Chemical characteristics of fimbriae of A. viscosus].

OBJECTIVE: To investigate the chemical characteristics of two purified fimbriae. METHODS: The specific antibodies against type I and type II fimbriae of A. viscosus were prepared and the purity of the two purified fimbriae had been identified by the specific antibodies. Then, chemical analysis and amino acid analysis of the two purified fimbriae were done. RESULTS: The two purified fimbriae were mainly composed of proteins and small amount of carbohydrate. The two types of fimbriae contained large amounts of aspartic acid, glutamic acid, alanine, lysine and glycine, and high percentage of nonpolar amino acid was analysed while basic amino acids were present in a very small amounts. CONCLUSION: These results may help to understand the relationship between the chemical characteristics of two types of fimbriae and their biological activity.

Actinomyces viscosus↗
PubMed1999

[A study on biological properties of fimbriae of A. viscosus. III. Adherence activity of fimbriae of A. viscosus].

OBJECTIVE: To investigate the adherence activity of two types of fimbriae of A. viscosus on tooth surface or with S. sanguis 34. METHODS: The inhibited adherence tests, coaggregation tests and the inhibited coaggregation tests were done. RESULTS: 1. The purified type I and type II fimbriae inhibited the adherence of A. viscosus to salivary-treated hydroxyapatite (SHA) and the two specific IgG to type I and type II fimbriae blocked the adsorption of strain T14V, strain 5519 and strain 5951 to SHA; 2. Only type II fimbria indirectly mediated the visible agglutination of S. sanguis 34 and only IgG to type II fimbriae inhibited coaggregation of strain T14V and strain 5915 with S. sanguis 34. CONCLUSION: Type I and type II fimbriae have adherence ability, and only type II fimbria has the agglutination activity. Additionally, the methods which were used to prepare fimbriae don't damage the biological activity of fimbriae.

Actinomyces viscosus↗
PubMed1999

[Effects of blocking the TGF alpha-EGFR autocrine loop on the growth of human pancreatic carcinoma cells in vitro].

OBJECTIVE: Investigate the effects of blocking the TGF alpha-EGFR autocrine loop on the growth of human pancreatic carcinoma. METHODS: The pCMV-AS-EGFR, a recombinant vector expressing antisense EGFR under the control of human CMV promotor was constructed and transfected the transformant PC-7/AS-TGF alpha cell line cells, which had been transfected by a recombinant retroviral vector expressing antisense TGF alpha. G418 resistant colonies were isolated and identified as PC-7/AS-TGF alpha/AS-EGFR. The integration and expression of exogenous and endogenous genes were detected by Southern blot and Northern blot analysis. Apoptosis was detected by DNA fragmentation, flow cytometry and in situ cell death detection. RESULTS: The cells which were double-transfected by the recombinant vectors showed the integration and expression of exogenous genes, and the downregulation of endogenous EGFR and cyclin D1 mRNA. 125I-EGF ligand binding test showed the binding affinity of the EGFR on the cell surface also reduced. The inhibition effect of cotransfecting of antisense TGF alpha and antisense EGFR was remarkable as compared with that of antisense TGF alpha alone. The incorporation rate of 3H-TdR reduced from 25% to 14.5%, and the growth inhibition rate increased from 78.6% to 86.0%. The ability of soft agar colony-formation was completely suppressed. CONCLUSIONS: These observations strongly support that the blockage of the expression of autocrine growth factor TGF alpha and its receptor EGFR was a potent way in circumventing the malignant properties of the pancreatic carcinoma cells.

Cell Division↗
PubMed1999

[Effects of antisense N-myc gene on nerve growth factor-induced differentiation of neuroblastoma cell line].

OBJECTIVE: The purpose of this study is to investigate the effects of antisense N-myc gene transfection on nerve growth factor-induced differentiation of neuroblastoma cell line. METHODS: Recombinant retroviral vector expressing antisense N-myc gene was constructed. Using the Transfectam Reagent, the recombinant vector was transduced into the human neuroblastoma cell line, IMR-32/NGFR, which was previously transfected by nerve growth factor receptor gene. The transformant cell line expressing antisense N-myc was established and studied by single chain RNA probe hybridization, immunocytochemistry, and nerve growth factor treatment to see whether nerve growth factor can induce differentiation in this transformant cell line and inhibition of N-myc expression. The TUNEL technique and electromicroscopy were used to detect apoptosis of the tumor cells. RESULTS: The cell line transduced by antisense N-myc expressed much less amount of N-myc both on mRNA and protein levels. After nerve growth factor treatment, remarkable morphological differentiation appeared in these cells. Apoptosis was also enhanced in these cells. CONCLUSIONS: Antisense N-myc transfection could specifically inhibit the expression of N-myc and promoted the nerve growth factor-induced differentiation of neuroblastoma cell line. Transfection of antisense N-myc could also enhance the process of apoptosis of the tumor cells.

Animals↗