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Yu Wang

Publications and source records attributed to Yu Wang.

At least 181 records · Page 10Linked to original sources
PubMed2005

Feasibility on systemic delivery of asialoorosomucoid complex to hepatic origin cells mediated by asialoglycoprotein receptor.

Receptor mediated gene delivery is a new gene transfer strategy. Asialoglycoprotein receptor (ASGP-R), the receptor of asialoorosomucoid (Asor), is specially expressed on the surface of hepatocyte. In this paper, the nuclide 131I was combined with Asor to form a kind of soluble nuclide-protein complex, which can be specifically endocytosed into hepatocyte by ASGP-R. After in travenous injection of the complex into experimental animals, the deposition of Asor in vivo and the targeting quality of hepatocyte was detected by ECT. This research testified the feasibility of targeting Asor complex delivery to hepatocyte mediated by ASGP-R in vivo, and provided foundation for the genetic diagnosis and gene therapy of hepatic cell-related diseases.

Animals↗
PubMed2005

Expression of MAGE-A1 mRNA is associated with gene hypomethylation in hepatocarcinoma cell lines.

BACKGROUND: A correlation between melanoma-associated antigen (MAGE) A1 mRNA expression and genome-wide hypomethylation has been observed in some carcinomas, but this relationship is not known in hepatocarcinoma. METHODS: Total RNA and genomic DNA were prepared from ten human hepatocarcinoma cell lines in which the genetic characteristics are stable. MAGE-1 mRNA expression was determined by reverse transcription polymerase chain reaction (RT-PCR), and the level of genome-wide demethylation was evaluated by enzyme digestion and Southern-blot assay. The methylation status of the MAGE-A1 gene promoter was measured by enzyme digestion and PCR. RESULTS: MAGE-A1 mRNA was detected in the hepatocarcinoma cell lines QGY-7703, SMMC-7721, HLE, BEL-7402, BEL-7404, and BEL-7405, which showed moderate to low levels of cell differentiation. In contrast, MAGE-A1 mRNA expression was not detected in the hepatoma cell lines HepG2215, HepG2, QGY-7701, and Huh7, which showed moderate to high levels of differentiation. The level of demethylation in MAGE-A1 mRNA-positive cell lines was much higher than that in MAGE-A1 mRNA-negative cell lines (P=0.02). CONCLUSIONS: The results suggest that MAGE-A1 mRNA expression in human hepatoma cell lines is associated with hypomethylation of the genome and the MAGE-A1 promoter domain. This study will be helpful to reveal the expression mechanisms of MAGE-like tumor antigens in cancer cells.

Antigens, Neoplasm↗
PubMed2005

Molecular cloning and characterization of a novel human C4orf13 gene, tentatively a member of the sodium bile acid cotransporter family.

By large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a novel human cDNA (C4orf13). This cDNA is 2706 bp in length, encoding a 340-amino-acid polypeptide that contains a typical SBF (sodium bile acid cotransporter family) domain and ten possible transmembrane segments. The putative protein C4orf13 shows high similarity with its orthologs in Mus musculus and Xenopus laevis. Human C4orf13 is mapped to chromosome 4q31.2 and contains 12 exons. RT-PCR analysis shows that human C4orf13 is widely expressed in human tissues, and the expression levels in liver and lung are relatively high, expression levels in placenta, kidney, spleen, and thymus are moderate, low levels of expression are detected in heart, prostate, and testis.

Amino Acid Sequence↗
PubMed2005

Gene selection from microarray data for cancer classification--a machine learning approach.

A DNA microarray can track the expression levels of thousands of genes simultaneously. Previous research has demonstrated that this technology can be useful in the classification of cancers. Cancer microarray data normally contains a small number of samples which have a large number of gene expression levels as features. To select relevant genes involved in different types of cancer remains a challenge. In order to extract useful gene information from cancer microarray data and reduce dimensionality, feature selection algorithms were systematically investigated in this study. Using a correlation-based feature selector combined with machine learning algorithms such as decision trees, naïve Bayes and support vector machines, we show that classification performance at least as good as published results can be obtained on acute leukemia and diffuse large B-cell lymphoma microarray data sets. We also demonstrate that a combined use of different classification and feature selection approaches makes it possible to select relevant genes with high confidence. This is also the first paper which discusses both computational and biological evidence for the involvement of zyxin in leukaemogenesis.

Algorithms↗
PubMed2005

Curative antitumor immune response is optimal with tumor irradiation followed by genetic induction of major histocompatibility complex class I and class II molecules and suppression of Ii protein.

Transfecting genes into tumors, to upregulate major histocompatibility complex (MHC) class I and class II molecules and inhibit MHC class II associated invariant chain (Ii), induces a potent anti-tumor immune response when preceded by tumor irradiation, in murine RM-9 prostate carcinoma. The transfected genes are cDNA plasmids for interferon-gamma (pIFN-gamma), MHC class II transactivator (pCIITA), an Ii reverse gene construct (pIi-RGC), and a subtherapeutic dose of adjuvant IL-2 (pIL-2). Responding mice rejected challenge with parental tumor and demonstrated tumor-specific cytotoxic T lymphocytes (CTLs). We have extended our investigation to determine the relative roles of each one of the four plasmids pIFN-gamma, pCIITA, pIi-RGC, and pIL-2 in conjunction with radiation for the induction of a curative immune response. Upregulation of MHC class I with pIFN-gamma or class II with pCIITA, separately, does not lead to a complete response even if supplemented with pIL-2 or pIi-RGC. An optimal and specific antitumor response is achieved in more than 50% of the mice when, after tumor irradiation, tumor cells are converted in situ to a MHC class I+/class II+/Ii- phenotype with pIFN-gamma, pCIITA, pIi-RGC, and pIL-2. We demonstrate further that both CD4+ helper T cells and CD8+ cytotoxic T cells are essential for induction of an antitumor response because in vivo depletion of either subset abrogates the response. The radiation contributes to the gene therapy by causing tumor debulking and increasing the permeability of tumors to infiltration of inflammatory cells.

Animals↗
PubMed2005

Regulation by hetC of genes required for heterocyst differentiation and cell division in Anabaena sp. strain PCC 7120.

Unlike those of the wild-type strain, proheterocysts of the Anabaena sp. strain PCC 7120 hetC strain keep dividing. ftsZ, the most critical cell division gene, is up-regulated in hetC proheterocysts. Heterocyst differentiation genes hglD, hglE, patB, nifB, and xisA are no longer expressed in the hetC mutant. hetC also regulates the expression of patA, a pattern formation gene.

ATP-Binding Cassette Transporters↗
PubMed2005

Study on the dynamic behavior of a DNA microarray.

A theoretical dynamic kinetic model was derived and a series of experiments were carried out using low-density microarrays in various concentrations of spotting probe ([P]) and labeling target ([T]). It has been shown that target and probe determined the signal intensity together. At a certain range of DNA concentration, the signal intensity was in proportion to spotting [P]. At the higher DNA concentrations, there was a decrease in hybridization signal intensity, especially in cDNA microarrays. Since the DNA microarray was constructed on a solid surface, steric hindrance, which is induced by the solid surface and the high [P], decreased the probe immobilization efficiency, leading to a decrease of the immobilized probe density. The decreased hybridization efficiency also caused the compression in signal intensity when the target increased. Nevertheless, the intensity ratio of Cy5 to Cy3 was not compressed within a microarray in the two-color system. The ratio of Cy5/Cy3 is only determined by the ratio of two targets and independent of the density and the types of probe. Therefore, the two-color fluorescent strategy is more reasonable and reliable in detection of differential gene expression. All these results indicate that the DNA microarray can be used to detect differently expressed genes, though it cannot be used to detect the absolute mRNA abundance.

Base Sequence↗
PubMed2005

Homogeneous high-throughput screening assays for HIV-1 integrase 3beta-processing and strand transfer activities.

HIV-1 integrase (HIV-IN) is a well-validated antiviral drug target catalyzing a multistep reaction to incorporate the HIV-1 provirus into the genome of the host cell. Small molecule inhibitors of HIV-1 integrase that specifically target the strand transfer step have demonstrated efficacy in the suppression of virus propagation. However, only few specific strand transfer inhibitors have been identified to date, and the need to screen for novel compound scaffolds persists. Here, the authors describe 2 homogeneous time-resolved fluorescent resonance energy transfer-based assays for the measurement of HIV-1 integrase 3'-processing and strand transfer activities. Both assays were optimized for high-throughput screening formats, and a diverse library containing more than 1 million compounds was screened in 1536-well plates for HIV-IN strand transfer inhibitors. As a result, compounds were found that selectively affect the enzymatic strand transfer reaction over 3beta processing. Moreover, several bioactive molecules were identified that inhibited HIV-1 reporter virus infection in cellular model systems. In conclusion, the assays presented herein have proven their utility for the identification of mechanistically interesting and biologically active inhibitors of HIV-1 integrase that hold potential for further development into potent antiviral drugs.

Antiviral Agents↗
PubMed2005

Manipulation of neuronal nitric oxide synthase within the paraventricular nucleus using adenovirus and antisense technology.

Congestive heart failure (CHF) is characterized by impaired cardiovascular reflexes and increased neurohumoral drive. The long-term sympatho-excitation increases the progression and risk of mortality during CHF. The paraventricular nucleus (PVN) of the hypothalamus is a very important central site for integration of sympathetic outflow and cardiovascular function. Within the PVN, nitric oxide (NO), mainly generated by neuronal nitric oxide synthase (nNOS), functions in inhibitory regulation of sympathetic outflow. Our previous study has indicated that in rats with experimental heart failure, the NO mechanism within the PVN is attenuated. We hypothesize that this alteration may contribute to the sympatho-excitation commonly observed in CHF. To investigate the role of NO within the PVN in sympathetic dysfunction in CHF, we have manipulated nNOS expression using adenoviral gene transfer of nNOS or nNOS antisense. These techniques have allowed us to observe the effects of alterations in nNOS on sympathetic outflow and cardiovascular function. In this chapter, we describe the methods for delivering nNOS adenoviral vector or nNOS antisense into the PVN using microinjection, as well as the protocols for detecting nNOS expression after these manipulations, using Western blot, NADPH-diaphorase staining, and immunofluorescent staining.

Adenoviridae↗
PubMed2005

Signal transduction pathways in androgen-dependent and -independent prostate cancer cell proliferation.

In a previous report, we showed that increased activation of Akt, a downstream effector of phosphoinositide 3-kinase (PI3K) together with decreased activation of extracellular-signal-regulated kinase (ERK), a member of the mitogen-activated protein kinase (MAPK) family, predicted poor clinical outcome in prostate cancer (Kreisberg et al. 2004 Cancer Research 64 5232-5236). We now show that Akt activation, but not ERK activation, is correlated with proliferation in human prostate tumors as estimated by the expression of the cell proliferation antigen Ki67. We verified these results in vitro, using the androgen-dependent prostate cancer cell line LNCaP and its androgen-independent clone C4-2 as models of prostate cancer of good and poor clinical outcome, respectively. C4-2 cells expressed higher Akt activation, lower ERK activation and increased proliferation compared with LNCaP cells, similar to cases of poor clinical outcome. The PI3K inhibitor LY294002, but not the MAPK/ERK kinase inhibitor PD98059, induced growth arrest in both cell lines. Transient transfection with constitutively active Akt increased proliferation while dominant negative Akt decreased it, thus showing that Akt plays an important role in prostate cancer proliferation. Akt regulates the expression and activation of the androgen receptor. Androgen receptor inhibition with Casodex induced growth arrest in LNCaP cells, but not in C4-2 cells. Another PI3K downstream effector, p70 S6 kinase, requires prior phosphorylation by mammalian target of rapamycin (mTOR) for complete activation. Activation of p70 S6 kinase was higher in C4-2 compared with LNCaP cells. Rapamycin, an mTOR inhibitor, had a growth-inhibitory effect in C4-2 cells, but not in LNCaP cells. Our data suggest a shift from a Casodex-sensitive proliferation pathway in LNCaP cells to a rapamycin-sensitive pathway in C4-2 cells.

Androgen Antagonists↗
PubMed2005

[Clinical features of 30 cases of amyloidosis].

OBJECTIVE: Clinical features of 30 cases of amyloidosis, a rare disease in China, were analyzed in order to improve the recognition of the disease here. METHODS: 30 cases of biopsy-proven amyloidosis, admitted to Beijing Friendship Hospital from July 1980 to December 2003 were retrospectively reviewed. RESULTS: 12 of the 30 cases were systemic amyloidosis. Among them 9 were primary amyloidosis, 1 secondary amyloidosis and 2 familial amyloid polyneuropathy. The other 18 cases were localized amyloidosis. Males (17) were more than females (13). In the 12 primary amyloidosis patients, kidney (75.00%), liver (58.33%), peripheral nervous system (58.33%) and heart (50.00%) were most commonly involved. Nonspecific symptoms such as fatigue, weight loss, hepatomegaly, limb numbness, edema and heavy albuminuria were the most common clinical manifestations. Localized amyloidosis involved only one organ, such as skin, alimentary tract and nasopharynx without evidences of a systemic disease. Excision of the localized amyloid deposits was performed in 13 cases. CONCLUSION: Systemic amyloidosis usually involves multiple organs and systems, leading to highly variable clinical manifestations. An increase in the vigilance of the awareness of this disease among clinicians will improve the possibilities for its diagnosis.

Adolescent↗
PubMed2005

[First report on assessment of the status of engraftment after allogeneic hematopoietic stem cell transplantation by using denaturing high-performance liquid chromatography].

Monitoring engraftment of donor cells after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is supposed to be important for the early diagnosis of graft failure or relapse of malignancy. Several techniques have been reported for this purpose. PCR-based assays analyzing polymorphic short tandem repeats (STR) as markers are attractive because they are sensitive and can be performed rapidly. The intent of this study was to test a novel approach for assessment of donor engraftment using denaturing high-performance liquid chromatography (DHPLC) combined with STR-PCR. The feasibility of this assay and the accuracy of semi-quantitative results were tested in-vitro by using serial DNA mixtures from unrelated individuals. The results showed that dilution experiments of the mock chimerism sample revealed a clear correlation between the percentage of donor or recipient DNA and the proportion of allele peak areas, with the limit of detection for a minor DNA percentage being 5%. Discrimination between donor and recipient was possible in all patients analyzed (n = 51) except for 5 patients whose pre-transplant samples were not available and identical twins in one case. STR results were the same as values obtained by capillary electrophoresis combined with fluorescence labeling multiply PCR. Results were also compared with data obtained with FISH analysis in a subgroup of patients receiving grafts from sex-mismatched donors or with PCR-detectable disease-specific gene products analysis. The results of the microsatellite analysis correlated well with the corresponding clinical findings. Full donor chimerism (FDC) were detected in all patients; decreasing values of donor chimerism were detected concomitantly with the appearance of relapse of disease in 3 patients. Samples from eight patients receiving HLA mismatched-haploidentical transplants from related donors together with cord blood transplants from unrelated donors were analyzed by this method. The results showed all 8 patients achieved FDC derived from related donors. It is concluded that this novel approach allows a rapid, sensitive, economical, auto-mated and non-isotopic STR-PCR testing, thus provides a reliable alternative for assessment of the status of engraftment after allo-HSCT.

Adolescent↗
PubMed2005

[Clinical efficacy and safety of emergent percutaneous coronary intervention for vein-grafts in the patients with acute myocardial infarction: comparison between age groups].

OBJECTIVE: To evaluate the efficacy and the safety of emergent primary percutaneous coronary intervention (PCI) in the saphenous vein bypass graft (SVBG) of acute myocardial infarction (AMI), and compare the results between aged -patients with non-aged patients. METHODS: Three hundred and nine consecutive AMI patients with culprit SVBG vessels, were analysed, including aged patients 213 cases(>or=70 years old), non-aged patients 96 cases(<70 years old), underwent the emergent primary PCI after confirmed below TIMI III perfusion(TIMI 0-TIMI II) in coronary angiographies. The immediate results and in-hospital outcomes were compared between two groups. RESULTS: Procedural successful rate, re-occlusion rate, and emergency re-CABG had no significant differences between two groups. The rate of slow-flow/no-reflow and in-hospital mortality rate were significantly higher in elderly group (19.7% vs 10.4%, 9.4% vs 4.2%, both P<0.05), with no difference in the rate of the using of distal protection devices between two groups. The comparison of the rate of direct stenting in slow-flow/no-reflow subgroup with normal-flow subgroup, had not showed statistic difference (73.5% vs 67.3%, P>0.05). There was no statistic difference of heavy hemorrhage between two different age groups. CONCLUSION: The primary PCI for the elderly AMI patients with infarction-related SVBG vessels, has higher risks in slow-flow/no-reflow and the mortality, even with using the distal protection devises and direct stents implantation.

Age Factors↗
PubMed2005

[Expression of MAGE-A1 in human hepatoma cell lines associated with genic hypomethylation].

OBJECTIVES: To investigate the correlation between MAGE-A1 mRNA expression and genic demethylation in hepatoma cell lines. METHODS: Total RNA and genomic DNA were prepared from 10 human hepatoma cell lines. MAGE-1 mRNA expression was determined with RT-PCR and the level of genome-wide demethylation was evaluated by enzyme digestion and Southern blot assay. The genomic DNA was digested by HpaII, then the promoter of MAGE-A1 gene was amplified with primers CDS21, EDP4 and CDS20. EDP4 and the PCR products were further hybridized with a probe to detect the methylation in the promoter of the MAGE-A1 gene. HLA-A locus was typed using SSP kit. RESULTS: In cell lines QGY-7703, SMMC-7721, HLE, BEL-7402, BEL-7404 and BEL-7405, MAGE-A1 mRNA expression was positive and cell differentiation was moderate or low. In cell lines of HepG2 2.2.15, HepG2, QGY-7701 and Huh7, MAGE-A1 mRNA expression was negative and cell differentiation was well or moderate. The level of genomic demethylation in MAGE-A1 mRNA positive cell lines was much higher than that in MAGE-A1 mRNA negative cell lines (t = 2.896, P = 0.02). The methylation analysis showed that methylation in the promoters of MAGE-A1 gene of HepG2 2.2.15, HepG2, QGY-7701 and Huh7 was high, and that methylation in those of SMMC-7721, HLE, BEL-7402, BEL-7404, and BEL-7405 was low. CONCLUSION: The results suggest that MAGE-A1 mRNA expression in the human hepatoma cell lines is associated with genic hypomethylation.

Antigens, Neoplasm↗
PubMed2005

[Vasoinhibitory effect of daltepartin sodium on human hepatocellular carcinoma in nude mice].

OBJECTIVES: To study the inhibition effect of Daltepartin Sodium (low molecular weight heparins) on human hepatocellular carcinoma (HCC) in nude mice. METHODS: Metastatic model of HCC was established in nude mice. The model mice were randomly divided into 4 groups; they were the control group (saline solution), chemotherapy group (fluorouracil and Cis-dichlorodiamine platinum), Daltepartin Sodium group (Daltepartin Sodium), combined treatment group (Daltepartin Sodium and chemotherapy). Tumor sizes, tumor inhibition rates, tumor metastases, intratumoral microvessel density (MVD), CD31 and AFP were evaluated. RESULTS: In comparison with the control and the chemotherapy group, the tumor sizes of the Daltepartin Sodium and the combined treatment group were significantly smaller; the tumor inhibitor rates were 0% versus 93.6%, 76.7%, 78.0%; MVD were 20.7+/-6.8 versus 18.2+/-2.6, 4.8+/-1.8 and 6.5+/-2.4; CD31 were 31.8+/-5.7 versus 25.5+/-5.1, 21.6+/-4.8 and 19.6+/-2.4; The incidence of liver metastasis was 80%, versus 70%, 20% and 10%; lung metastasis was 70% versus 60%, 20% and 10%; the peritoneal metastasis was 90% versus 60%, 30%and 30%. AFP were 121.8 ng/ml+/-31.4 ng/ml versus 21.5 ng/ml+/-13.3 ng/ml, 75.6 ng/ml+/-29.7 ng/ml and 55.8 ng/ml+/-38.0 mg/ml. Inhibiting effects of growth and metastasis of HCC in chemotherapy, Daltepartin Sodium and combined treatment groups were significantly different from those of the control group (F=9.191, P < 0.01), Daltepartin Sodium inhibited the angiogensis in the tumors more effectively than that in the control and chemotherapy groups (F=4.937, P < 0.01). CONCLUSION: Daltepartin Sodium can inhibit tumor growth and metastasis by inhibiting tumor angiogenesis in our nude mice HCC model.

Angiogenesis Inhibitors↗
PubMed2005

[Intracytoplasmic sperm injection using cryopreserved-thawed testicular spermatozoa with testicular fine needle aspiration].

OBJECTIVE: To evaluate the effect of intracytoplasmic sperm injection (ICSI) using cryopreserved-thawed testicular spermatozoa with testicular fine needle aspiration (TEFNA) in patients with non-obstructive azoospermia. METHODS: Sixty-two patients underwent TEFNA. Mature testicular spermatozoa were found in 35 cases of patients and the testicular tissues were cryopreserved for later ICSI. Ovarian stimulation included a long protocol of GnRHa/FSH/hCG. Oocyte retrieval was performed under transvaginal ultrasound guidance, and ICSI conducted with cryopreserved-thawed testicular spermatozoa. RESULTS: A total of 35 couples underwent 35 ICSI cycles using cryopreserved-thawed testicular spermatozoa with testicular fine needle aspiration. The clinical pregnancy rate was 37.14% (13/35). CONCLUSION: ICSI using cryopreserved-thawed testicular spermatozoa with testicular fine needle aspiration is a main and effective method in the treatment of non-obstructive azoospermia, which can avoid further testicular fine needle aspiration.

Adult↗
PubMed2005

[Expression of feedback-resistant aspartate kinase gene in Corynebacterium crenatum].

The AEC-resistant aspartate kinase gene from C. crenatum CD945 was cloned into vector pJC1. Its expression was investigated both in the wild type C. crenatum AS1.542 and its mutant C. crenatum CD945. The result showed that C. crenatum AS1.542 harboring AK(fbr) gene could grow on the defined medium with the co-existence of 12 mg/mL both of AEC and L-threonine respectively. Overexpression of AK(fbr) gene in C. crenatum CD945 results in a 4-fold increase of specific enzyme activity than the parental strain. The amplification of the activity of aspartate kinase yields 22% increase of L-lysine production and 23% increase of L-lysine productivity without affecting the growth rate.

Aspartate Kinase↗