Biomedical subjects

Qiang Liu

Publications and source records attributed to Qiang Liu.

At least 145 records · Page 8Linked to original sources

PubMed2002

Production of chemokines and reactive oxygen species by human neutrophils stimulated by Helicobacter pylori.

BACKGROUND: Bacteria have different characteristics in stimulation of human neutrophils to produce reactive oxygen species (ROS) and chemokines. This study examined the ability of Helicobacter pylori to induce production of ROS and chemokines by human neutrophils. METHODS: H. pylori strains (1.5 x 108 CFU/ml) were cocultured with 5 x 104 neutrophils isolated from healthy subjects. Samples were incubated with human serum with or without IgG antibodies to H. pylori. ROS production was measured using luminol-dependent chemiluminescence (LmCL), and the concentrations of chemokines (IL-8, RANTES, MIP-1alpha and MCP-1) were measured by ELISA. RESULTS: The mean of the highest LmCL (peak height; PH) value stimulated by H. pylori was 3318 in the absence of serum. PH increased to 4687 when incubated with anti-H. pylori antibody-positive sera (p <.001) but antibody-negative sera did not affect LmCL response. The mean final concentration of IL-8 produced in the absence of serum was 142.6 pg/ml. Increased IL-8 production was seen by addition of antibody positive serum (p <.01). IL-8 production was not significantly correlated with production of ROS. On the other hand, H. pylori stimulation did not induce neutrophil production of RANTES, MIP-1alpha or MCP-1. CONCLUSIONS: H. pylori was capable of inducing IL-8 production by human neutrophils, but not C-C chemokines. Production of C-X-C dominant chemokine by neutrophils is consistent with the pathological characteristics of H. pylori-induced gastritis, where persistent neutrophil infiltration is present.

Cells, Cultured↗

PubMed2002

Activation of p38 and ERK signaling during adenovirus vector cell entry lead to expression of the C-X-C chemokine IP-10.

The use of adenovirus vectors for human gene therapy is limited by potent inflammatory responses that result in significant morbidity. In kidney-derived epithelial cells (REC), activation of extracellular signal-regulated kinase 1/2 (ERK) and p38 kinase (p38) pathways occurred within 20 min of transduction with the serotype 5 adenovirus vector AdCMV beta gal. Inhibition of ERK and p38 with U0126 and SB203580, respectively, reduced the expression of IP-10 mRNA following transduction with AdCMV beta gal. To determine the role of the coxsackievirus-adenovirus receptor (CAR) or alpha(v) integrins in the activation of ERK and p38 and the expression of IP-10, REC cells were transduced with the fiber-modified and RGD-deleted adenovirus vectors AdL.F(RAEK-HA) and AdL.PB(HA), respectively. Compared with the wild-type capsid vector Ad5Luc, transduction with AdL.F(RAEK-HA) and AdL.PB(HA) resulted in reduced ERK-p38 activation and less IP-10 mRNA expression. The decreased IP-10 expression induced by the tropism-modified vectors was due to diminished transduction, since increasing multiplicity of infection resulted in increased IP-10 expression. Inhibition of adenovirus penetration with bafilomycin A1 or ammonium chloride attenuated the activation of ERK-p38 and IP-10 mRNA expression following infection, suggesting that endosomal escape was required to trigger these pathways. In vivo, direct inhibition of ERK and p38 signaling pathways inhibited adenovirus vector-induced IP-10 expression in mouse liver 1 h following transduction. These results demonstrate the importance of signaling via ERK and p38 in the early host response to adenovirus vectors and will permit the development of novel strategies to improve the safety and efficacy of these agents in human gene therapy.

Adenovirus Infections, Human↗

PubMed2002

Differential activation of innate immune responses by adenovirus and adeno-associated virus vectors.

Adenovirus vectors induce acute inflammation of infected tissues due to activation of the innate immune system and expression of numerous chemokines and cytokines in transduced target cells. In contrast, adeno-associated virus (AAV) vectors are not associated with significant inflammation experimentally or clinically. We tested the ability of AAV vectors to induce the expression of chemokines in vitro and to activate the innate immune system in vivo. In human HeLa cells and murine renal epithelium-derived cells (REC cells) the adenovirus vector AdlacZ induced the expression of multiple inflammatory chemokines including RANTES, interferon-inducible protein 10 (IP-10), interleukin-8 (IL-8), MIP-1beta, and MIP-2 in a dose-dependent manner. The use of AAVlacZ did not induce the expression of these chemokines above baseline levels despite 40-fold-greater titers than AdlacZ and greater amounts of intracellular AAVlacZ genomes according to Southern and slot blot analysis. This finding confirmed that the lack of AAVlacZ induction of chemokine was not due to reduced transduction. In DBA/2 mice, the intravenous administration of 2.5 x 10(11) particles of AAVlacZ resulted in the rapid induction of liver tumor necrosis factor alpha (TNF-alpha), RANTES, IP-10, MIP-1beta, MCP-1, and MIP-2 mRNAs. However, 6 h following injection, chemokine mRNA levels returned to baseline. As expected, administration of 10-fold less AdlacZ caused an induction of liver TNF-alpha and chemokine mRNAs that persisted for more than 24 h posttransduction. Whereas intravenous administration of 2.5 x 10(11) particles of AAVlacZ triggered a transient infiltration of neutrophils and CD11b(+) cells into liver, this response stood in contrast to widespread inflammation and toxicity induced by AdlacZ. Kupffer cell depletion abolished AAVlacZ but not AdlacZ-induced chemokine expression and neutrophil infiltration. In summary, these results show that AAV vectors activate the innate immune system to a lesser extent than do adenovirus vectors and offer a possible explanation for the reduced inflammatory properties of AAV compared to adenovirus vectors.

Adenoviruses, Human↗

PubMed2002

Histopathologic changes induced by cellophane wrapping of the pancreas are unaffected by cigarette smoke exposure in hamsters.

This study tests whether exposure to cigarette smoke alone or combined with cellophane wrapping of the pancreas increases the development of microscopic abnormalities in the pancreas of Syrian golden hamsters. Ninety hamsters were randomly divided into 4 groups. Thirty-five hamsters were exposed to 3 continuous hours of cigarette smoke daily for 3 months following celiotomy to cellophane wrap the gastric lobe of the pancreas (group 1). Thirty-two hamsters were not exposed to continuous cigarette smoke and had the wrap surgery alone (group 2). Twelve hamsters were exposed to cigarette smoke and had no surgery (group 3). Eleven hamsters had no exposure to cigarette smoke and no surgery (group 4). All of the hamsters were sacrificed after 3 months. The gastric (wrapped) and splenic (unwrapped) lobes of the pancreas were reviewed grossly and histologically. In all 4 groups, there were no gross abnormalities in either lobe of the pancreas. Histopathologic evaluation of the gastric lobes from group 1 showed that 13 of 35 lobes (37%) had pancreatitis (11 chronic, 1 acute, and 1 both). In group 2, 12 of 32 (38%) gastric lobes had pancreatitis (10 chronic, 2 acute). The incidence of pancreatitis in groups 1 and 2 was significantly higher than in groups 3 (0/12; p < 0.04) and 4 (0/11; p < 0.03), respectively. A significantly lower incidence of pancreatitis was found in the splenic lobes of all 4 groups when compared to gastric lobes in groups 1 and 2. Three of the 67 cellophane-wrapped glands had ductal hyperplasia. The effects of cellophane wrapping of the pancreas, both in the wrapped and unwrapped areas, induced changes of pancreatitis and hyperplasia that may be preneoplastic. Cigarette smoking, alone or combined with cellophane wrapping, did not cause these changes. Longer exposure to cigarette smoke may be needed to cause premalignant changes in the hamster pancreas.

Animals↗

PubMed2002

Cystatin 11: a new member of the cystatin type 2 family.

Cystatin (CST)11, a novel member of the CST type 2 family of cysteine protease inhibitors, was identified in Macaca mulatta epididymis by subtractive hybridization cloning. The human CST11 gene on chromosome 20p11.2 is located near three other CST genes expressed predominantly in the male reproductive tract. The CST11 gene spans three exons, a structure similar to that of other CST family 2 genes. An exon 2-deleted alternative transcript (CST11Delta2) was also identified. CST11 mRNA is expressed only in the epididymis as judged by Northern blot hybridization and is androgen regulated. The protein is most abundant in the initial segment, but is detected throughout the epididymis and on ejaculated human sperm. The calculated tertiary structure of CST11 reveals that the three regions corresponding to the protease inhibitory wedge of CST3 are similarly juxtaposed in CST11, consistent with protease inhibitor function. Intact and exon 2-deleted CST11 recombinant proteins were tested for antibacterial activity. After a 2-h incubation of Escherichia coli with 50 microg/ml recombinant CST11 or CST11Delta2, bacterial colony-forming units were reduced to 30% of control, indicating that both forms have antimicrobial activity.

Amino Acid Sequence↗

PubMed2002

Truncated amplification: a method for high-fidelity template-driven nucleic acid amplification.

The error rate of conventional PCR is problematic when amplifying from single cells or amplifying segments for protein functional analysis by in vitro translation. We describe truncated amplification, a method for high-fidelity amplification in which DNA polymerase errors are not propagated efficiently and original DNA templates exert greater influence on the amplification process. Truncated amplification utilizes pairs of oligonucleotides and thermal cycling, but it differs from PCR. Truncated amplification amplifies non-exponentially with one or two chimeric oligonucleotides and produces truncated terminal products that are no more than three rounds of replication from the original template. Exon 6 of the p53 gene was utilized as a model system to demonstrate proof of principle. Chimeric oligonucleotides containing three 3'-->5' reversed-deoxynucleotides or 2'-OMe-ribonucleotides at 6-8 nucleotides from the 3 'terminus retained sequence specificity and primer extension activity. With PfuTurbo but not with Taq or Vent (exo-) DNA polymerases, the modified nucleotides completely truncated the DNA polymerase elongation. The resulting truncated terminal products are not templates for further amplification because of the short length of the 3' complementary region. Truncated amplific ation can amplify quadratically or geometrically depending on whether two or one chimeric oligonucleotides are used. Truncated amplification is a promising approach when template-driven amplification is desired to increase thefrequency of error-free products.

Base Sequence↗

PubMed2002

[Rebamipide].

Explore the source record for details and available documents.

Alanine↗

PubMed2002

[Expression, purification of the recombinant protein fragment of the monkey epididymis expressed gene ESc-615 and preparation of polyclonal antisera to it].

ESc-615 is a gene which was specifically expressed in epididymis, newly discovered in our laboratory. To elucidate the function of ESc-6 15 in sperm maturation and fertilization at the protein level, its C-terminal 310 amino ac id residues fragment was expressed in E.coli and used to immunize rabbits to obtain polyclonal antiserum with titer of 100 000. The antisera could detect th e antigen as low as 3 ng. A 63 kD protein in rat epididymis protein extracts could be detected in Western blot by using this particular antiserum, in accordance with the size of Esc-615 homologue polypeptide deduced from its cDNA. Immunostaining results showed that Esc-615 was a secreted protein and could bind sperm s, which was similar with other carboxylesterases in male reproductive system; t he positive staining was eliminated after antigen absorption. All these results showed that this antiserum was not only effective but also highly specific, providing a useful tool in further functional studies of Esc-615.

Animals↗

PubMed2002

Seroprevalence of porcine circovirus type 2 in swine populations in Canada and Costa Rica.

Porcine circovirus (PCV) was recently divided into 2 antigenically distinct types that differ (65% amino acid identity) in the protein encoded by open reading frame 2 (ORF2). Porcine circovirus 1 is apparently non-pathogenic and, in contrast, PCV2 is associated with porcine multisystemic wasting syndrome (PMWS). Our objective was to determine the extent of exposure of normal pigs in Canada and Costa Rica to PCV2. Recombinant DNA techniques were used to produce an antigen from ORF2 of PCV2 that was suitable for the detection of antibody in swine sera. The presence of PCV2 nucleotide sequences was detected using polymerase chain reaction (PCR) techniques. Using these tests, specific antibody and nucleotide sequences were demonstrated in sera from a cohort of pigs during a PMWS outbreak. Antibody was detected in normal, healthy hogs slaughtered in Canada (82.4% of 386) and in Costa Rica (14.6% of 322). This is the first report indicating the presence of PCV2 in Latin America. More than 50% of these sera also contained PCV2 nucleotide sequence. Although these hogs were healthy when slaughtered, they were infected with PCV2 and may have previously been ill. The widespread occurrence of PCV2 in swine suggests that this virus is adapted to replication in porcine tissue.

Animals↗

PubMed2002

[Effects of Azone of different concentrations on percutaneous absorption of baicalin in vitro].

OBJECTIVE: To study the effects of azone on the percutaneous absorption of baicalin in vitro. METHODS: Using the skin of nude mice as the cutaneous barrier, the rate constants of percutaneous absorption of baicalin at various concentrations of Azone were determined. RESULTS: The rate constants were 76.07, 89.23, 167.36, 238.61, 200.45 and 171.49 microgram cm-2.h-1 respectively corresponding to the concentrations of Azone at 0, 2%, 4%, 6%, 8%, and 10%. CONCLUSION: C Azone can enhance percutaneous absorption of baicalin, exerting its maximum effect at the concentration of 6%.

Administration, Cutaneous↗

PubMed2002

[An exploration of the preventive effects on lanthanum chloride on enteral bacterial translocation in scalded rats].

OBJECTIVE: To explore the preventive effect of lanthanum chloride on enteral bacterial translocation in scalded rats. METHODS: Ninety Sprague-Dawley (SD) rats were employed in the study and randomly divided into three groups, i.e. normal control (A), burn control (B) and treatment (C) groups. Plasmid PUC19 labelled by JM109 was transfected to Escherichia coli (E. coli), so that restriction endonuclease finger - print image spectrum analysis could be applied to the tracing and quantification of the translocation of E. coli from intestine to mesenteric lymph nodes (MLNs) and blood. The intestinal tissue contents of endotoxin (ET), nitric oxide (NO), nitric oxide synthase (NOS), malondialdehyde (MDA) and superoxide dismutase (SOD) were determined. RESULTS: It was identified that the bacteria in MLNs and blood exhibited the same gene map with those from gastric gavage in B and C groups. But the bacterial quantity in MLNs in C group on 3 postburn day (PBD) was much lower than that in B group (P < 0.05). The intestinal MDA content in C group on 1 and 3 PBDs was obviously higher than that in B group (P < 0.05). CONCLUSION: Bacteria (E. coli) could be translocated from gut to MLNs and blood, which could be evidently alleviated by lanthanum chloride by means of its bactericidal property, inhibition of NOS activity, so that NO production decreased, and its ability to increase SOD activity leading to less production of MDA.

Animals↗

PubMed2001

Classification of cell lineage and anatomical site, and prognosis of extranodal T-cell lymphoma -- natural killer cell, cytotoxic T lymphocyte, and non-NK/CTL types.

Due to their minority among the non-Hodgkin lymphomas, classification of extranodal T-cell lymphomas, including those of the natural killer (NK) cell type, has long been controversial and unclear, and the clinical outcome is not well clarified. Recently, new well-defined disease entities have been described based on tumor cell biology combined with anatomical site, clinical features, Epstein-Barr virus (EBV) status, and cell lineage as determined by immunophenotype and genotype. Cytological features are usually not specific, and there are no morphologic correlates with the classification of extranodal T/NK-cell lymphomas. From a human T-cell lymphotropic virus type 1 (HTLV-1) endemic area in Japan, we report here the analysis of 144 cases of extranodal T-cell lymphoma, from which fresh tissues were available. As the clinicopathological features were known, we simply reclassified the cases according to cell lineage and anatomical site. The extranodal T-cell lymphomas were classified into three types on the basis of cell lineage: (1) natural killer cell (NK) type [sCD3-, CD56+, T-cell receptor gene (TCR) germline], (2) cytotoxic T lymphocyte (CTL) type [sCD3+, TIA-1+, TCR rearranged, CD8+/-, CD4-/+], and (3) non-NK/CTL type [sCD3+, TIA-1-, TCR rearranged, CD4+/-, CD8-/+]. In addition to cell lineage, the anatomical site and clinical features were added for subclassification. NK type tumors (35 cases) included the lymphoblastic type, nasal/nasal-type NK lymphoma, and NK leukemia. The CTL type (46 cases) included anaplastic large cell lymphoma (ALCL), cutaneous type, intestinal, gamma delta T-cell type, and an unspecified type. The non-NK/CTL type (63 cases) included adult T-cell leukemia/lymphoma (ATLL), mycosis fungoides (MF), and an unspecified type. With the exception of ATLL and MF, most extranodal T-cell lymphomas had a cytotoxic phenotype of NK type or CTL type and were often associated with EBV infection. MF and the unspecified type within the non-NK/CTL tumors, with the exception of ATLL, had a favorable prognosis. However, NK and CTL types, with the exception of ALCL, were associated with a poor prognosis. Our results indicate that anatomical site and cell lineage are useful predictors of clinical outcomes of extranodal T-cell lymphomas.

Antigens, CD↗

PubMed2001

Validated zinc finger protein designs for all 16 GNN DNA triplet targets.

The Cys(2)-His(2)-type zinc finger DNA-binding proteins can be engineered to bind specifically to many different DNA sequences. A single zinc finger typically binds to a 3-4-base pair DNA subsite. One strategy for design is to identify highly specific fingers that recognize each of the 64 possible DNA triplets. We started with a subgroup of the 64 triplets, the GNN-binding fingers. The GNN-binding fingers have been examined in several studies, but previous studies did not produce specific fingers for all of the 16 GNN triplets. These previous studies did not provide any information on the possible positional or context effects on the performance of these fingers. To identify the most specific design and take the possible positional effects into consideration, we did a large-scale site selection experiment on our GNN designs. From this study, we identified very specific fingers for 14 of the 16 GNN triplets, demonstrating for the first time a clear positional dependence for many of the designs. Further systematic specificity study reveals that the in vivo functionality of these zinc finger proteins in a reporter assay depends on their binding affinities to their target sequences, thus giving a better understanding of how these zinc finger proteins might function inside cells.

Amino Acid Sequence↗

PubMed2001

Detection and localization of pectin methylesterase isoforms in pollen tubes of Nicotiana tabacum L.

Pectin methylesterases (PMEs) were detected in tobacco ( Nicotiana tabacum) pollen tubes grown in vitro. Seven PME isoforms exhibiting a wide isoelectric-point (pI) range (5.3-9.1) were found in crude extracts of pollen tubes. These isoforms were mainly retrieved in supernatants after low- and high-speed separation of the crude extract. Two isoforms, with pIs 5.5 and 7.3 and molecular weight about 158 kDa, were detected by immunoblotting with anti-flax PME antiserum. Localization of pectins and PME isoforms in pollen tubes was investigated by immunogold labelling with JIM5 monoclonal antibodies and anti-flax PME antiserum, respectively. In germinated pollen grains, two PME isoforms were mainly detected in the exine, Golgi apparatus and secretory vesicles. In pollen tubes the same two PME isoforms were distributed along the outer face of the plasma membrane in the vicinity of the inner layer of the cell wall, in the Golgi and around secretory vesicles. In pollen grains, PME isoforms were, in some cases, mixed with acidic pectins in proximity to the outer surface of the plasma membrane. In pollen tubes the presence of PMEs inside secretory vesicles carrying esterified pectins supports the hypothesis that, during pollen tube growth, PMEs could be transferred by secretory vesicles in a precursor form and be activated at the tip where exocytosis takes place.

Blotting, Western↗

PubMed2000

Differences in Lifestyle of a Smoking and Non-smoking Population in Japan.

If smokers have different lifestyle including dietary habit in comparison to non-smokers, this difference have an influence on the evaluation of the risks of smoking for tobacco-related diseases or the design of anti-smoking campaigns. In Japan, 1,745 men over the age of 40 were surveyed regarding health consciousness in 1996 and 2,136 men between the ages of 50 and 65 were surveyed regarding dietary habits in 1993-1994. Comparative analysis was done among the smoking and non-smoking groups. The rate of participation in cancer mass-screening for smokers was significantly lower than for non-smokers. Smokers had consumed significantly lower amounts of vegetables, fruits and beans, which are well known beneficial factors for health than non-smokers, and had consumed more salt, salty food and alcohol, which are well known risk factors for health. It is suggested that smokers have disadvantageous characteristics for promoting and maintaining a healthy lifestyle more than in non-smokers. Accordingly, to evaluate the risk of smoking for tobacco-related diseases in epidemiological researches, we should properly treat these data as confounding factors. Furthermore, anti-smoking campaigns should be performed considering these differences.

Journal Article↗

PubMed1998

A prostate-specific Protein Factor Inhibits the Interaction of Androgen Receptors with Hormone Response Elements.

The fragments of the androgen receptor (amino acids: 359-732) and of the glucocorticoid receptor (amino acids: 396-548) were expressed in E. coli as fusion proteins with GST. Both fusion proteins, denoted GST-AR and GST-GR, contained the DNA-binding domain and some flanking amino acids. In gel retardation assay both fusion proteins could bind the androgen/glucocorticoid response element (ARE/GRE). We found that both cytosol and nuclear extracts from rat ventral prostate (v.p), but not from other source tested could abolish the interaction of GST-AR and GST-GR with ARE/GRE (from C3 (1) gene and MMTV LTR). The inhibition was androgen-dependent and sensitive to temperature and trypsin treatment. It implies that a protein inhibitor was present in the rat ventral prostate.

Journal Article↗

PubMed1998

Identification of the Subunits of C3P4 and Estimation of Their Molecular Weights by UV Cross-linking Assay.

The subunits and their molecular weights of an unknown DNA-binding protein C3P4 induced by androgen were studied by UV cross-linking assay. The results indicate that there are two subunits with molecular weights of about 110 kD and 27 kD in the C3P4 complex. Ferguson plot further shows the molecular weight of native C3P4 to be about 127 kD. It suggests that C3P4 very likely exists as heterodimer composed of one 110 kD subunit and one 27 kD subunit. The 110 kD subunit may play an important role in DNA-binding.

Journal Article↗

PubMedDate not supplied

Ecabet sodium attenuates reactive oxygen species produced by neutrophils after priming with bacterial lipopolysaccharides.

The pathogenic roles of reactive oxygen species (ROS) have been implicated in ulcerative colitis (UC). The aim of this study was to examine the effects of ecabet sodium on ROS produced by human neutrophils, particularly after being primed by bacterial lipopolysaccharides (LPS). Neutrophils were isolated from six healthy volunteers. Each well of a 96-well microplate received neutrophil suspension (1.0 x 10(5) cells) and the plates were incubated at 37 degrees C for 30 min with or without E. coli LPS (f.c. 0.001 ng/ micro L). Ecabet sodium (f.c. 0-5.0 mg/mL) was added before starting or after finishing the incubation. Neutrophils were stimulated by opsonized zymosan (OZ; 1.0 mg/mL) or calcium ionophore (A21837; 0.3 micro mol/L) and luminol-dependent chemiluminescence response was measured using a Lumi Box H-1000. Ecabet sodium attenuated ROS production at a concentration of 5.0 mg/mL (p < 0.05) in LPS-primed neutrophils. However, attenuating effects were not significantly different when ecabet sodium was added before or after the incubation with E. coli LPS. Ecabet sodium may have some attenuating effects on ROS produced by human neutrophils even after neutrophils are primed by bacterial LPS. These results may explain, in part, the therapeutic effects of ecabet sodium for UC.

Abietanes↗