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Biomedical subjects

L H Wu

Publications and source records attributed to L H Wu.

At least 19 recordsLinked to original sources
PubMed2006

Distribution of polycyclic aromatic hydrocarbons in thirty typical soil profiles in the Yangtze River Delta region, east China.

Polycyclic aromatic hydrocarbons (PAHs) were quantified in 30 soil profiles from the Yangtze River Delta Region, in east China. Relative concentrations of PAH compounds with different benzene rings and ratios of fluoranthene to fluoranthene plus pyrene and benz(a)anthracene to benz(a)anthracene plus chrysene were used to identify the possible sources of soil PAHs. Total concentrations of 15 PAHs in topsoils ranged from 8.6 to 3881 microg kg(-1) with an average of 397 microg kg(-1). Half of the soil samples were considered to be contaminated with PAHs (>200 microg kg(-1)) and two sampling sites were heavily polluted by PAHs with concentrations >1000 microg kg(-1). Phenanthrene was found in soils below a depth of 100 cm in half of the sampling sites, but the detectable ratio of benzo(a)pyrene decreased sharply from 100% in topsoil to 0 in the 4th horizon.

Benz(a)Anthracenes↗
PubMed2006

Degradation of benzo[a]pyrene in an experimentally contaminated paddy soil by vetiver grass (Vetiveria zizanioides).

A pot experiment was conducted to study the effect of growing vetiver grass on the biodegradation of benzo[a]pyrene (B[a]P) under glasshouse conditions. Plant biomass, microbial biomass C and degradation of B[a]P were determined. B[a]P disappeared faster in the plant treatments than in unplanted controls. Disappearance of B[a]P was accompanied by an increase in soil microbial biomass C. Vetiver grass may promote the biodegradation of B[a]P under flooded conditions by plant roots by stimulating the microbial biomass. Microbial biomass was the main factor affecting dissipation of B[a]P under flooded conditions.

Benzopyrenes↗
PubMed2003

Effects of EDTA and low molecular weight organic acids on soil solution properties of a heavy metal polluted soil.

A pot experiment was conducted to study the effects of EDTA and low molecular weight organic acids (LMWOA) on the pH, total organic carbon (TOC) and heavy metals in the soil solution in the rhizosphere of Brassica juncea grown in a paddy soil contaminated with Cu, Zn, Pb and Cd. The results show that EDTA and LMWOA have no effect on the soil solution pH. EDTA addition significantly increased the TOC concentrations in the soil solution. The TOC concentrations in treatments with EDTA were significantly higher than those in treatments with LMWOA. Adding 3 mmol kg(-1) EDTA to the soil markedly increased the total concentrations of Cu, Zn, Pb and Cd in the soil solution. Compared to EDTA, LMWOA had a very small effect on the metal concentrations. Total concentrations in the soil solution followed the sequence: EDTA >> citric acid (CA) approximately oxalic acid (OA) approximately malic acid (MA) for Cu and Pb; EDTA >> MA >> CA approximately OA for Zn; and EDTA >> MA >> CA > OA for Cd. The labile concentrations of Cu, Zn, Pb and Cd showed similar trends to the total concentrations.

Cadmium↗
PubMed2000

Serum interleukin-10 but not interleukin-6 is related to clinical outcome in patients with resectable hepatocellular carcinoma.

OBJECTIVE: To evaluate the clinical significance of preoperative serum levels of interleukin-10 (IL-10) and interleukin-6 (IL-6) in patients with resectable hepatocellular carcinoma (HCC). SUMMARY BACKGROUND DATA: IL-10 is an immunosuppressive factor and IL-6 is a multifunctional cytokine that plays a role in host defense mechanisms. Both have been reported to be related to the disease prognosis in some human solid tumors. Their role in human HCC has not been investigated. METHODS: Preoperative serum samples of 67 patients with HCC who underwent potentially curative resection and 27 normal healthy donors were assayed. Levels of IL-10 and IL-6 were determined by enzyme-linked immunosorbent assay. The clinical significance of serum IL-10 and IL-6 was evaluated and compared with conventional clinicopathologic factors. RESULTS: Levels of IL-10 and IL-6 were significantly higher in patients with HCC than in healthy subjects. There was no correlation between IL-10 and IL-6 levels. Tumor resection resulted in a decrease in IL-10 and IL-6 levels. On univariate analysis, patients with high IL-10 levels had a worse disease-free survival, but IL-6 levels had no correlation with the disease-free survival. Multivariate analysis identified IL-10 levels as a predictor of postresectional outcome, in addition to the well-established clinical risk factors. CONCLUSIONS: In patients with HCC, the preoperative serum IL-10 level is related to the clinical outcome. IL-10 may play an important role in the progression of HCC.

Carcinoma, Hepatocellular↗
PubMed1999

New reporter cell lines to study macrophage-tropic HIV envelope protein-mediated cell-cell fusion.

The infection of human cells by HIV-1 virus can be mimicked by a fusion process between cells expressing the HIV envelope protein (Env) and cells expressing both human CD4 (huCD4) and appropriate human chemokine receptors. In this study, a macrophage-tropic (M-tropic) HIV cell-cell fusion assay was established that utilized huCD4, human CCR5 (huCCR5), and HIV ADAgpl60 as fusion components and a Gal4/VP16-activated luciferase as a reporter system. By combining CHO cells expressing huCD4 and huCCR5 with CHO cells expressing HIV ADAgpl60, a 300-fold increase in luciferase activity could be elicited relative to control. No luciferase activity was detected when HXB2gpl60 (T-tropic) was used instead of ADAgpl60 (M-tropic) as the fusion partner in the assay. Addition of anti-huCD4 (RPA-T4) or anti-huCCR5 (2D7) monoclonal antibodies in the assay significantly inhibited the fusion event; in contrast, an anti-CXCR4 (12G5) monoclonal antibody had little effect, indicating that the fusion assay was huCD4 and huCCR5 dependent. The cell-cell fusion occurred in a time-dependent manner; the maximum luciferase activity was detected about 8 hr after mixing the cells. The fusion events could also be monitored by another reporter system in which Gal4/VP16 activated green fluorescent protein (GFP) was used as the reporter instead of luciferase. In combination with fluorescence microscopy, the GFP reporter system allowed visualization of the fusion events in real time. Compared with previously described HIV fusion models, this system has several advantages, including simplicity, sensitivity, and the ability to allow continuous monitoring of the HIV cell-cell fusion event. Finally, this cell-cell fusion system is easily adapted to study other HIV fusion events.

Animals↗
PubMed1999

Prognostic value of MIB-1 index and DNA ploidy in resectable ampulla of Vater carcinoma.

OBJECTIVE: To evaluate the prognostic value of the proliferative factors, MIB-1 index, DNA ploidy, and S-phase fraction, and further to determine the independent prognostic factors in ampulla of Vater carcinoma after pancreaticoduodenectomy. SUMMARY BACKGROUND DATA: Cell kinetics are important indicators of the biologic behavior of various human tumors, but only a few authors have reported the application of cell proliferative factors in ampulla of Vater carcinoma. METHODS: Patients undergoing pancreaticoduodenectomy for ampulla of Vater carcinoma were included. Proliferative factors, MIB-1 index, and DNA contents, measured by flow cytometry, were evaluated and compared with the conventional clinicopathologic factors. RESULTS: Ninety resectable ampulla of Vater carcinomas were included. By univariate analysis, MIB-1 index, DNA ploidy, S-phase fraction, stage, and lymph node status were significant prognostic factors. The 5-year survival rate was 40.7% for tumors with MIB-1 index < or =15% and 0% for those with MIB-1 index >15%. Diploid tumors had a significantly better prognosis than aneuploid. Outcomes of stage I and II tumors were more favorable than those of stage III and IV. After multivariate analysis, MIB-1 index, DNA ploidy, and stage remained as the independent prognostic factors. Among the three independent prognostic factors, MIB-1 index was the most powerful. CONCLUSIONS: Both MIB-1 index and DNA ploidy provide important prognostic value and potentially complement the conventional prognostic factors in resectable ampulla of Vater carcinoma. MIB-1 index is the most powerful independent prognostic factor.

Adult↗
PubMed1998

Isolation of the intact molecule and ectodomain of C-erbB-2 oncoprotein from SK-BR-3 cells and development of immunoassays on microplate.

We isolated both the intact molecule (p185) and the ectodomain (p120) of c-erbB-2 oncoprotein from SK-BR-3 breast tumor cells. The p120 was extracted from the cells by 0.05 M phosphate buffer, pH 7.2, whereas the extraction of the p185 required the presence of a detergent, such as 1% Triton X-100 in 0.05 M Tris buffer. Protease inhibitors were also included in the extraction buffer during the isolation of p185 in order to prevent cleavage of p185 to p120 by an unknown protease apparently also present in the extract. In case there was any p120 in the p185 preparation, the p120 could be separated from p185 by chromatography on a Superose 12 column. Using the p120 and p185 as calibrators, we have established two microplate sandwich immunoassays: one measures both p185 and p120 (total assay) and the other is specific for the p185. Since capturing and detecting antibodies used in the total assay react against the extracellular domain of the c-erbB-2 oncoprotein, they can therefore be used to measure the p120 in serum and p185 in breast tumor tissue cytosol. On the other hand, the p185 specific assay uses the capturing antibody against the cytosolic domain of the oncoprotein and consequently can only measure p185 in breast tumor tissue cytosol.

Antibodies, Neoplasm↗
PubMed1998

Bacterial expression and characterization of human recombinant apolipoprotein(a) kringle IV type 9.

Elevated plasma lipoprotein(a) [Lp(a)] is an independent risk factor for several vascular diseases. Lp(a) particles are generated through the formation of a disulfide bond between Cys4057 of kringle IV type 9, (KIVt9), of the multikringle apolipoprotein(a) [apo(a)] and a cysteine in apoB-100 low-density lipoprotein (LDL). To better understand this interaction, we have expressed and purified KIVt9 from Escherichia coli as a His-Tag fusionprotein. Dithiothreitol (DTT)-treated purified KIVt9 migrated as a single approximately 17. 3-kDa band on SDS-PAGE gels. Without DTT, an additional band twice the molecular weight of KIVt9 was observed. The double-size band presumably resulted from dimerization of individual kringles, through their unpaired cysteine residues, since a mutation Cys4057 --> Ser ([Ser4057]KIVt9) abolished dimer formation. Using a gel-shift assay, we showed that KIVt9 could couple to 14-amino-acid apoB-100 synthetic peptides (apoB3732-3745 and apoB4319-4332) containing Cys3734 or Cys4326. Both of these apoB-100 cysteines have been reported to associate with apo(a) to generate Lp(a). In the presence of either apoB-100 peptide, KIVt9 was shifted to a higher molecular weight that was consistent with the covalent addition of a 1.2-kDa apoB-100 peptide. Identical apoB-100 peptides in which the cysteine residues were replaced by alanine ([Ala3734]apoB3732-3745 and [Ala4326]apoB4319-4332) had no effect in the gel-shift assay. Furthermore, [Ser4057]KIVt9 did not covalently interact with apoB3732-3745 or apoB4319-4332. These results indicated that KIVt9 couples to the Cys-apoB-100 peptides through a disulfide linkage. This system may be suitable for further investigating the apo(a)/apoB-100 coupling reaction and the structure of KIVt9 through X-ray crystallographic studies.

Apolipoprotein B-100↗
PubMed1998

Flow-cytometric DNA content analysis of oesophageal carcinoma. Comparison between tumour and sequential non-tumour mucosae.

The DNA content in oesophageal carcinoma and in sequential non-tumour mucosa was evaluated in 35 patients with oesophageal carcinoma, to explore the hypotheses that DNA distribution pattern and S-phase fraction can reflect malignant potential and that DNA aneuploidy can provide an early-warning signal of developing cancer. DNA flow cytometry was performed on 129 specimens from the tumours and on 119 specimens from non-tumour mucosa. Control specimens from gastric fundus had normal diploid DNA content and low S-phase fraction. Aneuploidy was found in 94.3% of the carcinoma specimens and intratumoral heterogeneity in 54.3%. Of the non-tumour specimens, 43.7% showed aneuploidy and none multiple aneuploidy. Pattern III distribution was present in 8.6% of the tumour specimens but not in non-tumour mucosa, where the incidence of aneuploidy rose with closeness to the tumour (p < 0.001). S-phase fraction was smaller in non-tumour than in tumour specimens (p < 0.0001). The study indicated that histologically tumour-free oesophageal mucosa may have a high malignant potential in patients with oesophageal carcinoma. The relative instability of such mucosa, with aneuploid cells and low S-phase fraction, may facilitate transition to abnormally proliferating cells in response to environmental signals. Cigarette smoking and alcohol may increase the risk of multicentric cancer development.

Adult↗
PubMed1998

Ki-67 expression as a prognostic marker in patients with hepatocellular carcinoma.

Ki-67 expression in tumours has been shown to be associated with prognosis in patients with hepatocellular carcinoma (HCC). In this study, primary HCC samples were obtained from 67 patients undergoing surgical resection. None of these patients had been subjected previously to any other form of therapy, such as arterial embolization or chemotherapy. Histologically normal liver tissues from liver resection for metastatic colon cancer were taken as controls (n = 8). Monoclonal antibody against Ki-67 was used for immunostaining and flow cytometry was used to measure tumour DNA ploidy. The mean Ki-67 labelling index (percentage of Ki-67-positive cells) of the HCC (26 +/- 22%; range 0.1-89%) was significantly higher than that of the normal controls (39 +/- 0.8%, P < 0.05). The mean Ki-67 labelling index (19 +/- 15%; n = 28) of the tumours with diploid DNA pattern was significantly lower than those with aneuploid DNA pattern (32 +/- 25%, n = 39; P = 0.01). Hepatocellular carcinoma patients (n = 47) with Ki-67 index > 10% had a significantly lower disease-free and overall survival than those (n = 20) with Ki-67 index < or = 10% (P = 0.0009 and P = 0.02, respectively). Multivariate analysis showed that Ki-67 expression and tumour node metastasis stage were two independent prognostic factors for disease-free and overall survival rates. Our results suggest that the expression of Ki-67 is an independent prognostic indicator for patients with HCC after resection and could be of assistance in the decision-making of adjuvant therapy.

Aged↗
PubMed1998

Cordyceps sinensis increases the expression of major histocompatibility complex class II antigens on human hepatoma cell line HA22T/VGH cells.

Previous studies suggest that down-regulation of the major histocompatibility complex (MHC) antigens on the cell surface of certain tumors results in an escape of immune surveillance. Cordyceps sinensis is well known for its modulatory effect on host immune system. To investigate the modulatory effect of Cordyceps sinensis on MHC class II antigen expression on hepatoma cells, immunostaining with monoclonal antibody (MAb) L243, against the HLA DR region of MHC class II antigens on human hepatoma cell line HA22T/VGH was analyzed by using flow cytofluorimetry. The degree of fluorescence intensity on L243(+) cells was expressed as relative mean fluorescence intensity (RMFI). The extract of Cordyceps sinensis (VGH-CS-ME-82, 40 micrograms/ml) was found to increase the MHC class II antigen expression on HA22T/VGH cells with the percentage of L243(+) cells 40.2 +/- 2.5 and RMFI 6.6 +/- 0.4; whereas cells without treatment disclosed the percentage of L243(+) cells 17.2 +/- 1.4 and RMFI 5.4 +/- 0.3, respectively (p < 0.05). There was a dose-related increase in the degree of fluorescence intensity in terms of RMFI on VGH-CS-ME-82 induced cells. The RMFI in cells treated with IFN-gamma 0, 0.2 and 5 ng/ml were 5.4 +/- 0.3, 8.2 +/- 0.4, and 24.9 +/- 1.5, respectively; whereas the RMFI in cells co-incubated with VGH-CS-ME-82 (40 micrograms/ml) and IFN-gamma 0, 0.2 ng/ml and 5 ng/ml were 6.7 +/- 0.2 (p < 0.05), 9.2 +/- 0.9 (p < 0.1) and 29.5 +/- 1.2 (p < 0.005), respectively. We conclude that VGH-CS-ME-82, either alone or with IFN-gamma induction, increases the MHC class II antigen expression on hepatoma cell line HA22T/VGH, which will shed light into the present immunotherapy, and make the host immune surveillance more effective against tumor cells with down-regulated MHC class II antigen expression.

Carcinoma, Hepatocellular↗
PubMed1998

Role of caudal in hindgut specification and gastrulation suggests homology between Drosophila amnioproctodeal invagination and vertebrate blastopore.

During early embryogenesis in Drosophila, caudal mRNA is distributed as a gradient with its highest level at the posterior of the embryo. This suggests that the Caudal homeodomain transcription factor might play a role in establishing the posterior domains of the embryo that undergo gastrulation and give rise to the posterior gut. By generating embryos lacking both the maternal and zygotic mRNA contribution, we show that caudal is essential for invagination of the hindgut primordium and for further specification and development of the hindgut. These effects are achieved by the function of caudal in activating different target genes, namely folded gastrulation, which is required for invagination of the posterior gut primordium, and fork head and wingless, which are required to promote development of the internalized hindgut primordium. caudal is not sufficient for hindgut gastrulation and development, however, as it does not play a significant role in activating expression of the genes tailless, huckebein, brachyenteron and bowel. We argue that caudal and other genes expressed at the posterior of the Drosophila embryo (fork head, brachyenteron and wingless) constitute a conserved constellation of genes that plays a required role in gastrulation and gut development.

Animals↗
PubMed1997

Class I and class II major histocompatibility complex antigens expression on human hepatocytes and hepatoma cells: an approach with high sensitivity and specificity.

The expression of gene products of the major histocompatibility complex (MHC) on the cell surface is known to play an important role in immunological responses. While some studies have reported the presence of MHC antigens on hepatocytes, information about specific, sensitive hepatocyte MHC antigen expression in various liver diseases is minimal. To investigate the expression of class I and class II MHC antigens on hepatocellular carcinoma (HCC) specimens, two-color flow cytometry was used to demonstrate MHC antigen expression on non-malignant and malignant hepatocytes using the hepatocyte-specific monoclonal antibody (MAb) 9B2 for selective gating and either MHC-specific W6/32 (class I) or Q5/13 (class II) MAb for MHC antigen detection. Non-malignant liver tissues demonstrated variable MHC antigen expression. Malignant hepatocytes isolated from resected HCC specimens as well as non-tumorous hepatocytes from these HCC specimens also disclosed various degrees of MHC antigen expression. Although we were not able to demonstrate a clear correlation between clinical outcome and MHC antigen expression in HCC, we conclude that the expression of MHC antigens on human hepatocytes and hepatoma cells can be accurately detected by flow cytometry using hepatocyte-specific MAb for selective gating and MHC-specific MAbs. Of note, two cases of non-malignant fetal liver tissues indicated that >95% of fetal hepatocytes expressed class I MHC antigens and <25% of fetal hepatocytes expressed class II MHC antigens. These findings may lead to further investigations into the progression of HCC cells or into the possible mechanisms of the hepatocellular carcinogenesis.

Antibodies, Monoclonal↗
PubMed1996

Heat shock and cytokines modulate the expression of adhesion molecules on different human gastric-cancer cell lines.

In order to understand the expression and modulation of adhesion molecules (AMs) on the surface of different gastric cancers, we studied 4 gastric-cancer cell lines including SC-M1, KATO-III, AGS and AZ-521. The expression of E-cadherin, integrins (beta1, beta2 and beta3), ICAMs (1 and 2), and CD11 (a, b and c) on the cells was detected by flow cytometry. We found that E-cadherin was only expressed on SC-M1 and KATO-III. CD29 (beta1 integrin) could be found in cells of all 4 lines. CD54 (ICAM- 1) could not be detected in AZ-521. In contrast, CD18 (beta2 integrin), CD61 (beta3 integrin), ICAM-2, CD11a, CD11b and CD11c were all absent from these cells. Heat-shock treatment (42.5 degrees C, 60 min) enhanced the expression of E-cadherin, CD29 and CD54 on SC-M1, and of CD29 on AGS. In addition, TNF-alpha (50U/ml) and IL-1beta (10U/ml) modulated the expression of these AMs, like heat-shock treatment. The increment of these adhesion molecules caused by heat shock, TNF-alpha and IL-1beta stimulation on SC-M1 was also confirmed by Western blot analysis. Functionally, these treatments increased the binding between normal human mononuclear cells and SC-Ml cells. The heat-shock treatment could induce a significant amount of TNF-alpha and IL-1beta release from SC-M1 and KATO-III, but seemed irrelevant to the expression of AMs. These results suggest that limited adhesion molecules were expressed on the surface of different gastric cancer cells. Heat shock, IL-1beta and TNF-alpha may selectively modulate the expression of these 3 molecules on some of the cells, and this is probably related to their antitumor effect.

Antigens, CD↗
PubMed1996

The unpredicted high affinities of a large number of naturally occurring tachykinins for chimeric NK1/NK3 receptors suggest a role for an inhibitory domain in determining receptor specificity.

Three chimeric receptors were constructed by exchanging exon sequences between human NK1 and NK3 receptor genes. The resulting chimeric receptors not only retained high affinities for their natural ligands substance P and neurokinin B but also exhibited surprisingly high affinities for other naturally occurring tachykinins including neurokinin A, neuropeptide K, neuropeptide gamma, eledoisin, kassinin, physalaemin, and phyllomedusin. In contrast, these chimeric receptors displayed a wide range of variability in their affinities for non-naturally occurring ligands including selective agonists and antagonists of NK1, NK2, and NK3 receptors. Since the only common feature among these naturally occurring neurokinin peptides is the conserved C-terminal sequences, our data suggest that these conserved sequences must play the major role in conferring high affinity binding to the chimeric receptors. To explain the apparently "improved" affinities of these naturally occurring ligands for the chimeric receptors as compared with their affinities for the parent NK1 and NK3 receptors, we are proposing that certain inhibitory domains that are present in the NK1 and/or NK3 receptors are compromised in these chimeric receptors. Upon disruption of these inhibitory domains during the formation of chimeras, the naturally occurring ligands can interact more favorably with chimeric receptors through their conserved C-terminal sequences. Based on this hypothesis, the binding affinities of natural tachykinin ligands may be largely determined by their conserved C-terminal sequences, whereas receptor selectivities of these ligands are influenced more by the presence or absence of inhibitory domains rather than specific binding domains on their target receptors.

Amino Acid Sequence↗