Biomedical subjects

B Wang

Publications and source records attributed to B Wang.

At least 181 records · Page 10Linked to original sources

PubMed2001

Mouse models of metastatic pancreatic adenocarcinoma.

Pancreatic adenocarcinoma is a deadly disease. Its etiology is unknown, and metastatic disease kills the majority of patients who have it. Effective prevention is clearly the ultimate goal for eradicating this disease provided that the effects of environmental and genetic elements on pancreatic cancer development are fully understood. Currently, it appears that the control of pancreatic cancer metastasis is of immediate urgency. Fulfillment of this difficult task relies on knowledge of the cellular and molecular biology of metastasis. The use of relevant animal models will help define each aspect of this complicated process.

Adenocarcinoma↗

PubMed2001

A novel, clinically relevant animal model of metastatic pancreatic adenocarcinoma biology and therapy.

In this study, we report a metastatic model of Panc02 murine pancreatic adenocarcinoma. Parental Panc02 cells were orthotopically implanted into the pancreas of syngeneic C57BL/6 mice. Tumor cells were isolated from liver micrometastases 90 d after tumor implantation and established as a culture (Panc02-H1). The Panc02-H1 cells were then implanted into the pancreas of mice. Liver metastases were then collected and established as Panc02-H2 cells. This process was repeated until the Panc02-H7 cell line was established. These cells were extremely aggressive after implantation as manifested by progressive growth in the pancreas, peritoneal dissemination, and distant metastasis to multiple organs, including the liver and lungs. Moreover, Panc02-H7 cells expressed the inducible nitric oxide synthase gene at a very low level in culture and produced highly vascularized tumors having a large number of infiltrating macrophages. Collectively, this model system should be a valuable tool for investigating the molecular mechanisms governing pancreatic cancer growth and metastasis and exploring potential treatment modalities for this disease.

Adenocarcinoma↗

PubMed2001

Sensitization to silk and childhood asthma in rural China.

OBJECTIVE: Sensitization to perennial aeroallergens is associated with asthma in industrialized countries with a Western lifestyle. Because silk products are commonly used in Chinese society, we were interested in examining the relation between sensitization to silk and asthma. DESIGN: Cross-sectional study of 871 children in 503 families living in Anqing, a predominantly rural province of China. RESULTS: After adjustment for age, gender, familial correlations, and sensitization to other aeroallergens, skin test reactivity to silk was an independent predictor of asthma (odds ratio = 2.6; 95% confidence interval = 1.2-5.7). This association became stronger after inclusion of the eosinophil count and history of parasitic diseases of the participants in the multivariate model (odds ratio = 3.6; 95% confidence interval = 1.4-8.9). CONCLUSION: Because sericulture is an important activity in China and other countries throughout the world, sensitization to silk may influence the pathogenesis and severity of asthma in people living in these nations.

Allergens↗

PubMed2001

Rescue of lethally irradiated mice from hematopoietic death by pre-exposure to 0.5 Gy X rays without recovery from peripheral blood cell depletion and its modification by OK432.

Exposing mice to 0.5 Gy X rays 2 weeks before lethal irradiation has been reported to induce marked radioresistance and to rescue them from hematopoietic death. Here we examined effects of the 0.5-Gy pre-exposure on hematological changes in C57BL mice that were lethally irradiated with 6.5 Gy X rays. Approximately 77% of pre-exposed mice survived 30 days after this irradiation, whereas 80% of mice that did not receive this pre-exposure died by day 20. However, regardless of the pre-exposure, peripheral blood cell counts decreased markedly by day 3 and reached a nadir at day 20. CFU-S in femur and CFU-GM in spleen had started to recover at day 10 and 14, respectively, but recovery of functional peripheral blood cells occurred later. The effect of pre-exposure on survival was altered by OK432, a bioresponse modifier; the effect depended on the timing of its administration. OK432 given 2 days before 0.5 Gy enhanced the protective effect of pre-exposure, resulting in the survival of 97% of the mice. In contrast, injection of OK432 1 day before or 2 days after pre-exposure led to 100% mortality. Thus the survival-promoting effect of 0.5 Gy could be altered by OK432. The OK432-induced changes in the survival of mice could not be attributed solely to hematological changes, as shown by blood cell counts and progenitor cell contents. These results suggest that radioresistance induced by pre-exposure to 0.5 Gy X rays is not stable, but rather varies with the physiological conditions, and can be modulated by factors such as OK432.

Animals↗

PubMed2001

Oral bacteria and respiratory infection: effects on respiratory pathogen adhesion and epithelial cell proinflammatory cytokine production.

Several microbiologic and epidemiologic studies have suggested an association between dental plaque, poor oral health, and respiratory diseases such as nosocomial pneumonia and chronic obstructive pulmonary disease (COPD). A number of hypotheses are suggested to help explain how oral bacteria may participate in the pathogenesis of respiratory infection. Resident bacteria in oral secretions are likely aspirated along with respiratory pathogens and may affect the adhesion of the later organisms to the respiratory epithelium. Preliminary studies performed in our laboratory suggest that oral bacteria may modulate the adhesion of respiratory pathogens to epithelial cell lines. In addition, oral bacterial products or cytokines in oral/pharyngeal aspirates may stimulate cytokine production from respiratory epithelial cells, resulting in recruitment of inflammatory cells. The resulting inflamed epithelium may be more susceptible to respiratory infection. Further preliminary data are presented that some species of oral bacteria may induce the release of proinflammatory cytokines from epithelial cell lines to an extent similar to that seen for respiratory pathogens.

Aggregatibacter actinomycetemcomitans↗

PubMed2001

Molecular mechanism about lymphogenous metastasis of hepatocarcinoma cells in mice.

AIM: To investigate the correlation between lymphogenous metastasis and matrix metalloproteinases (MMPs) activity and the expression of Fas ligand of tumor cells in lymph nodes. METHODS: Fifty-six inbred 615-mice were equally divided into 2 groups and inoculated with Hca-F and Hca-P cells. Their lymph node metastatic rates were examined. Growth fraction of lymphocytes in host lymph nodes was detected by flow cytometry. The Hca-F and Hca-P cells were cultured with extract of lymph node, liver or spleen. The quantity of MMPs in these supernatants was examined by zymographic analysis. The expression of Fas ligand, PCNA, Bcl-2 protein of Hca-F and Hca-P cells in the mice were examined by immunohistochemistry. The apoptosis signals of macro-phages in lymph nodes were observed with in situ DNA fragmentation. RESULTS: On the 28th day post-inoculation, the lymph node metastatic rate of HcaF was 80%(16/20), whereas that of Hca-P was 25%(5/20). The growth fraction of lymphocytes was as follows: in the Hca-F cells, the proliferating peak of lymphocytes appeared on the 14th day post inoculation and then decreased rapidly, while in HcaP cells, the peak appeared on the 7th day post inoculation and then kept at a high level. With the extract of lymph node, the quantity of the MMP-9 activity increased (P<0.01) and active MMP-9 and MMP-2 were produced by both Hca-F and Hca-P tumor cells, which did not produce MMPs without the extract of lymph node or with the extracts of the liver and spleen. The expression of Fas Ligand of Hca-F cells was stronger than that of Hca-P cells (P <0.01). The expressions of PCNA and Bcl-2 protein of Hca-F cells in the tumors of inoculated area were the same as that of Hca-P cells. In situ DNA fragmentation showed that the positive signals of macrophages were around Hca-F cells. CONCLUSION: Secretion of MMPs which was associated with metastatic ability of Hca-F and Hca-P tumor cells depends on the environment of lymph nodes. The increased expression of Fas ligand protein of Hca-F tumor cells with high lymphogenous metastatic potential in lymph nodes may help tumor cells escape from being killed by host lymphocytes.

Animals↗

PubMed2001

A synthetic triptycene bisquinone, which blocks nucleoside transport and induces DNA fragmentation, retains its cytotoxic efficacy in daunorubicin-resistant HL-60 cell lines.

In contrast to the parent triptycene (code name TT0), triptycene bisquinone (code name TT2) is cytostatic (IC50: 300 nM) and cytotoxic (IC50: 230 nM) in wild-type (WT), drug-sensitive HL-60 cells (HL-60-S) at day 4. Therefore, the effects of this new quinone antitumor drug were assessed and compared to those of daunorubicin (DAU, daunomycin) in the multidrug-resistant (MDR) HL-60-RV and HL-60-R8 sublines, which respectively overexpress P-glycoprotein (P-gp) or multidrug resistance-associated protein (MRP). In contrast to DAU, which loses its cytostatic [resistance factors (RFs): 22.9-35.7] and cytotoxic (RFs: 23.8-31.3) activities in MDR sublines, TT2 decreases tumor cell proliferation (RFs: 0.9-1.3) and viability (RFs: 0.9-1.5) as effectively in HL-60-S as in HL-60-RV and HL-60-R8 cells at days 2 and 4. Similarly, DAU inhibits the rate of DNA synthesis less effectively in MDR than in parental HL-60 cells (RFs: 8.1-11.9) but TT2 decreases the incorporation of 3[H]-thymidine into DNA to the same degree in HL-60-S, HL-60-RV and HL-60-R8 cells (RFs: 1.2). In contrast to DAU, which is inactive, the advantage of TT2 is its ability to block the cellular transport of purine and pyrimidine nucleosides in WT tumor cells, an effect which persists in both MDR sublines (RFs: 1.0-1.2). Moreover, the concentrations of DAU which induce maximal DNA cleavage in HL-60-S cells at 24 h lose all or most of their DNA-damaging activity in HL-60-RV and HL-60-R8 cells, whereas treatments with 4 microM TT2 produce similar peaks of DNA fragmentation in all WT and MDR cell lines. Since TT2 not only mimics the antitumor effects of DAU but also blocks nucleoside transport and retains its effectiveness in MDR cells that have already developed different mechanisms of resistance to DAU, this new quinone antitumor drug might be valuable to develop new means of polychemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

Investigation on the rheological properties of hepatocellular carcinoma cells and their relevance to cytoskeleton structure.

OBJECTIVE: To investigate the relevance of the rheological properties, i.e., viscoelasticities and adhesion to basement membrane components coated surface, of both hepatocytes and hepatocellular carcinoma (HCC) cells to the cytoskeleton structure. METHODS: Micropipette aspiration technique was adopted to measure viscoelastic coefficients and adhesion forces to 2 microg/ml collagen IV/1.25 microg/ml laminin coated surface of the cells. Two kinds of cytoskeleton perturbing agents, colchicine and cytochalasin D, were used to treat both HCC cells and hepatocytes and the effects of these treatments on cell viscoelastic coefficients and cell adhesion forces were investigated. RESULTS: Upon treatment of cells with colchicine in a concentration range of 1 to 60 mg/L, the elastic coefficients, especially the first elastic coefficient K1, and adhesion forces of hepatocytes generally tended to increase or increased significantly while, in contrast, viscoelastic coefficients and adhesion forces of HCC cells decreased obviously. Upon treatment of cells with cytochalasin D in a concentration range of 0.25-5.00 mg/L, viscoelastic coefficients of both hepatocytes and HCC cells decreased uniformly, with a larger magnitude for the decrease in elastic coefficients and adhesion forces of HCC cells than for those of hepatocytes. Adhesion forces of hepatocytes and HCC cells onto collagen IV/laminin coated surface varied similarly as viscoelastic coefficients under the action of the cytoskeleton perturbing agents. A significant positive correlation existed between changes of HCC cell adhesion forces on collagen IV/laminin coated surfaces and those of cell elastic coefficients (P<0.01). CONCLUSIONS: The effects of cochicine and cytochalasin D on rheological properties of HCC cells differed significantly either in ways or extents from those on rheological properties of hepatocytes. These results might reflect the difference in the state of cytoskeleton structure and function among these two kinds of cells.

Carcinoma, Hepatocellular↗

PubMed2001

[Expression of tumor suppressor genes p16, p21 and p53 in a pair of lung adenocarcinoma cell lines with different metastasis potentials: Anip973 and AGZY83-a].

OBJECTIVE: In order to investigate the suppression effect of tumor suppressor genes in lung adenocarcinoma. METHODS: p16 and p21 expression vectors were transfected into a pair of lung adenocarcinoma cell lines with different metastasis potentials: Anip973(high metastasis potential)and AGZY83-a (low metastasis potential). In the mean time, AGZY83-a, Anip973, AGZY83-ap16 and Anip973p16 were infected with recombinant adenovirus encoding wild- type p53 gene. The suppression effects of these genes were evaluated by cell growth curve, MTT, cloning efficiency assay, flow cytometric analysis and TUNEL technique. RESULTS: Overexpression of p16 gene in Anip973 and AGZY83-a could only lengthen the G(1) phase while increased expression of p21 in both of the cell lines was associated with significant lengthening of G(1) phase, decreased proliferation potential and decreased cloning efficiency. High efficient expression of wild-type p53 gene in AGZY83-a, Anip973, Anip973p16 and AGZY83-ap16 inhibited the growth of these four kinds of lung cancer cells and killed the cells in the end. Apoptosis was detected in all the four kinds of cells. The suppression effect of p53 gene was higher in Anip973 and Anip973p16 than in AGZY83-a and AGZY83-ap16 while co-expression of p53 and p16 in this pair of cell lines inhibited the cells more efficiently as compared with the expression of p53 gene. CONCLUSION: Increased expression of p21 gene suppressed the lung adenocarcinoma cells by G(1) arrest and the co-transfection of tumor suppressor genes p16 and p53 into the lung adenocarcinoma cell line proved more effective in lung cancer gene therapy.

Adenocarcinoma↗

PubMed2001

[Effects of TNF-alpha on IL-8 mRNA expression in endothelial cells].

As a kind of chemokine, IL-8 plays an important role in inflammatory reaction. Its expression in endothelial cells is regulated by a variety of cytokines. In this study, after incubating cultured human umbilical vein endothelial cells(HUVECs) with TNF-alpha for different time, we employed RT-PCR to assay IL-8 mRNA expression and immunocytochemical staining to detect NF-kappa B activation in HUVECs. The results revealed: (1) IL-8 mRNA expressed little in untreated HUVECs; after HUVECs was pre-incubated with TNF-alpha for 1 hour, IL-8 mRNA expression increased greatly, and it increased further after pre-incubated for 3 hours; however, when HUVECs was pre-incubated with TNF-alpha for 6 hours, IL-8 mRNA expression decreased, and it almost decreased to basal level when pre-incubated for 9 hours; (2) the immunoreactivity of NF-kappa B p65 in the nuclei of untreated HUVECs was negative; it became positive in the nuclei of HUVECs pre-incubated with TNF-alpha for 1 hour and 3 hours; it became weak positive in the nuclei of HUVECs pre-incubated with TNF-alpha for 6 hours, and after 9 hours, pre-incubation, the immunoreactivity of NF-kappa B p65 in the nuclei of HUVECs was negative. These results implied that TNF-alpha was capable of inducing IL-8 gene expression and activation NF-kappa B. and Their time courses were similar, thus suggesting that the induction of IL-8 gene expression by TNF-alpha is probably due to the activation of NF-kappa B.

Cells, Cultured↗

PubMed2001

[Effects of laminar shear stress on IL-8 mRNA expression in endothelial cells].

This study sought to demonstrate that IL-8 expression in endothelial cells is regulated by not only chemical factors but also mechanical factors. After pretreating cultured human umbilical vein endothelial cells (HUVECs) with shear stress for different periods of time, we employed RT-PCR to assay IL-8 mRNA expression and immunocytochemical staining to detect NF-kappa B activation in HUVECs. The results showed: 1. IL-8 mRNA expressed little in HUVECs untreated or pretreated with low laiminar shear stress for 0.5 h; IL-8 mRNA expression increased when HUVECs were pretreated with low laminar shear stress for 1 h, and it increased further when HUVECs were pretreated for 2 h; 2. The immunoreactivity of NF-kappa B p65 in the nuclei of HUVECs untreated or pretreated with low laminar shear stress for 0.5 h was negative, while it became weak positive in the nuclei of HUVECs pretreated with shear stress for 1 h and positive in the nuclei of HUVECs pretreated for 2 h. The findings implied that low laminar shear stress was capable of inducing IL-8 gene expression and activating NF-kappa B, which were both time-dependent. The induction of IL-8 gene expression by laminar shear stress is probably due to the activation of NF-kappa B. On these grounds we come to the conclusion that IL-8 expression induced in endothelial cells by low shear stress may play an important role in the genesis and development of both inflammation and arterioatherosclerosis.

Cells, Cultured↗

PubMed2001

[Herbal compound 861 inhibits NF-kappa B binding activity of hepatic stellate cells in vitro].

OBJECTIVE: To investigate the effect of Cpd 861 on nuclear factor-kappa B (NF-kappa B) binding activity of hepatic stellate cells (HSC) in vitro. METHODS: The study was carried out on the culture of hepatic stellate cell line, 5mg/ml of Cpd 861 was added and incubated for 48 hours. NF-kappa B binding activity was evaluated by electrophoretic mobility shift assays. IL-6 and sICAM-1 levels in the cultured supernatant were detected by ELISA. Cell apoptosis was detected by flow cytometry and TUNEL. RESULTS: Cpd 861 suppressed the binding activity of NF-kappa B in HSCs compared with the control group. Moreover, IL-6 and sICAM-1 levels in the cultured supernatant were decreased (P<0.05) and apoptosis rate of HSCs was increased after Cpd 861 incubation (P<0.01). CONCLUSIONS: The inhibitory effect on NF-kappa B binding activity might be part of the cellular mechanism of Cpd 861 to treat liver fibrosis.

Animals↗

PubMed2001

[Immune response induced by hepatitis B DNA vaccine pCI-S-IRES- ProT alpha].

OBJECTIVE: To investigate immune response in mice inoculated with DNA vaccine. METHODS: pCI-S and pCI-S-IRES- ProT alpha were constructed by gene technology, transferred into cell line NIH-3T3 mediated by lipofectamine. Mice were inoculated with these plasmids too. HBsAg and HBsAb were detected by ELISA, and transcriptions of these plasmids were detected by RT-PCR. RESULTS: pCI-S -IRES- ProT alpha, and pCI-S were effectively expressed in cultured cells and vaccinated animals. Humoral immune and specific T-cell proliferative responses were stronger in pCI-S-IRES group than pCI-S group. CONCLUSIONS: Plasmids coexpression of prothymosin alpha and hepatitis B surface antigen can improve immune responses significantly.

Animals↗

PubMed2001

[Study on the association of transporter associated with antigen processing gene with ankylosing spondylitis and HLA-B27 in Han nationality].

OBJECTIVE: To investigate the association between transporter associated with antigen processing(TAP) gene and ankylosing spondylitis(AS) as well as HLA-B27. METHODS: PCR-SSO was used to analyze the frequencies of TAP alleles and variant amino acids of TAP in 48 patients (B27(+)) with AS and 123 normal individuals (B27(+) or B27(-)). RESULTS: The phenotypes of Ile/Ile, Asp/Asp were over-presented for TAP1 and Val/Val, Ala/Thr, Stop/Stop for TAP2 in Han nationality. For each TAP there were four alleles: TAP1*0101, TAP1*0201, TAP1*0301, TAP1*0401, and TAP2*0101, TAP2*0102, TAP2*0201, TAP2*0202. In the research subjects, hybridization blanks accounted for 9.9%(17/171) of TAP1 and 15.8%(27/171) of TAP2. No difference was found in the distribution of TAP alleles between the AS patients(B27(+)) and normal controls(B27(+) or B27(-)). In the patients group the frequency of phenotype in codon of 333 (Val/Val) was significantly decreased as compared with that of the healthy controls(B27(+))(P<0.05). In addition, the frequency of phenotype Ala/Ala(665) was significantly decreased and that of Ala/Thr was significantly increased in normal controls(B27(-)), compared with those in normal controls(B27(+))(P<0.05). CONCLUSION: It is possible that there are new TAP alleles in Han nationality. No association was found between TAP alleles and AS. And the homozygosity for codon 333 which is Val/Val seems to offer resistance to AS among those HLA-B27(+) individuals. In normal individuals, negative correlation was found between heterozygote Ala/Thr and B27, and possibly there was positive correlation between phenotype Ala/Ala and B27.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

[A study on city motor vehicle emission factors by tunnel test].

Applying the principle of tunnel test to run a typical across-river tunnel test in Guangzhou city, 48 h-online-monitor data include pollutant concentration, traffic activity and meteorological data were gained. The average motor vehicle emission factors of NOx, CO, SO2, PM10 and HC were calculated using mass balance which are 1.379, 15.404, 0.142, 0.637, 1.857 g/km. vehicle respectively. Based on that, combined emission factors of 8 types of city vehicles were calculated using linear regression. The result basically showed the character and level of motor vehicle emission in Chinese city.

Vehicle Emissions↗

PubMed2001

[Molecular identification and mapping of a maize gene (Rf3) in S-type CMS using AFLP, RFLP and SCAR techniques].

The maize CMS-S near isogenic line (NIL) developed by author and the backcross progeny (BC1) derived from it were used to identify molecular markers linked to the Rf3 gene and subsequently determine its chromosomal location on the linkage map of maize. Bulk segreant analysis was performed using AFLP technique. From the survey of AFLP primer combination, two AFLP markers, (EcoRI-AGG/MseI-CAC and EcoRI-AAC/MseI-CAG), which were named RR6 and RR7 respectively, linked to the Rf3 gene were identified. However, AFLP marker RR6 showed polymorphism between parents, and bulks were used to survey the available 100 individuals of the BC1 population, 2 out of 100 shed recombination. The recombination-rate was 2%. The genetic distance between Rf3 gene and AFLP marker RR6, was approximately 2.0 cM. And then, the RR6 was successfully cloned and sequenced, primer synthesized and converted to SCAR marker so that PCR marker can be developed for the marker-assisted selection. In RFLP analysis, marker RR6 linked to Rf3 was found to be located between RFLP loci asg20 and php20581b, and mapped on chromosome 2L.

Chromosome Mapping↗

PubMed2001

[Application of isonucleus and isocytoplasmic lines in the study of maize CMS].

Between wild fertile type (F) and its sterile mutant (cms), if their nucleus and cytoplasm are the same, this wild fertile type (F) and its sterile mutant (cms) are called isonucleus and isocytoplasmic lines. The maize mtDNAs of isonucleus and isocytoplasmic lines (I), wild fertile type 478(F) and its sterile mutant 478-cms, were analyzed by RAPD. 94 primers were screened, 3 polymorphic products, OPZ-19(420), OPAA-15(600) and OPS-01(400), were amplified between 478(F) and 478-cms. The results showed that mtDNAs in isonucleus and isocytoplasmic lines were more homologous than that in others. There is minor mtDNA difference between the fertile type (F) and its sterile type (cms) in a pair of isonucleus and isocytoplasmic lines. The polymorphism detected in isonucleus and isocytoplasmic lines may be more closely linked with the gene of fertility. Therefore, isonucleus and isocytoplasmic line is an excellent system in the study of CMS. Sister isonucleus and isocytoplasmic lines are consisted of 2 groups of isonucleus and isocytoplasmic lines in which their nucleus are not all the same but closely related, their cytoplasm are the same. Using sister isonucleus and isocytoplasmic lines is equal to determining the change of fertility by transferring one cytoplasm into the isonucleus. Isonucleus and isocytoplasmic lines (II) are consisted of Su478(F) and Su478-cms. Isonucleus and isocytoplasmic lines (I) and (II) are sister isonucleus and isocytoplasmic lines. The polymorphic products, OPZ-19(420) and OPAA-15(600), can also be obtained in isonucleus and isocytoplasmic lines (II). The 2 polymorphic products OPZ-19(420) and OPAA-15(600) are existed in both of the isonucleus and isocytoplasmic lines. This showed that isonucleus and isocytoplasmic lines are practicable in the study of CMS, and that common polymorphism in isonucleus and isocytoplasmic lines may be related more directly to fertility.

Cell Nucleus↗

PubMed2001

Insights into molecular mechanisms of contact hypersensitivity gained from gene knockout studies.

Contact hypersensitivity (CHS), a dendritic-cell (DC)-dependent, T-cell-mediated skin immune response to reactive haptens, has been a subject of intense research for many years. The molecular mechanisms underlying CHS are complicated and are not fully understood. During the past few years, varieties of gene-targeted knockout mice have been used in the study of CHS. Such studies have contributed significantly to our understanding of the mechanisms responsible for the initiation of CHS. This review focuses on insights into molecular requirements for CHS gained from knockout studies.

Animals↗