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Jia Liu

Publications and source records attributed to Jia Liu.

At least 91 records · Page 5Linked to original sources
PubMed2004

[Study on significance of single nucleotide polymorphisms in the redox domain of aprimidinic/apurinic endonuclease/redox factor-1 gene in Chinese sporadic colorectal cancer].

OBJECTIVE: To investigate the relationship between the single nucleotide polymorphisms(SNPs) in the redox domain of aprimidinic/apurinic endonuclease/redox factor-1(APEX) gene and the development of sporadic colorectal cancer. METHODS: One hundred and fifty cases of sporadic colorectal cancers and 143 peripheral blood samples from healthy population were screened for genetic polymorphisms or mutations in the redox domain by denaturing gradient gel electrophoresis followed by DNA sequencing. RESULTS: There were two SNPs identified in the redox domain of APEX gene, namely, 453G to T and 1247A to G. The gene frequencies of 453T and 1247G were 1.3% and 5.7%, respectively, in patient group, while 1.05% and 4.55%, respectively, in healthy population. The genotype distribution at the two sites in healthy population was consistent with Hardy-Weinberg equilibrium. There was no difference in gene frequencies at the two sites between cancer patients and healthy population. CONCLUSION: The polymorphisms in the redox domain of APEX gene are irrelevant to the development of sporadic colorectal cancer, but their distribution may vary greatly among tribes.

Aged↗
PubMed2004

[Report on difficulty in blood group identification due to anti-H antibody in three cases].

Anti-H antibody belongs to IgM type cold antibody, which often induces the unconformity of positive and reverse typing and leads to the difficulty in clinical blood typing. Anti-H antibody was found during identification of the counter blood group in 3 cases. The antibody was found to be active at 37 degrees C, room temperature and 4 degrees C when determined by blood group serology, and was finally analyzed to be IgM. It is suggested that not to give erythrocytes of O group unreasoningly to blood recipient of AB group during emergent moment, but instead, to give same type of blood. If there was no same type of blood during urgent events, O type erythrocytes could be employed after being matched by saline centrifuging with host side coincidence and screened by incomplete method. In this case, anti-H antibody leading to adverse-reaction in blood transfusion should be prevented.

ABO Blood-Group System↗
PubMed2004

Frequent translocalization of beta-catenin in gastric cancers and its relevance to tumor progression.

Altered distribution of beta-catenin has been found in many human malignancies including gastric cancer, but its reason(s) and biological implications have not yet been fully clarified. By the methods of frozen tissue array-based immunohistochemistry, RT-PCR and PCR-SSCP followed by DNA sequencing, the patterns of beta-catenin distribution in the subtypes of gastric cancers and their premalignant and non-cancerous counterparts were examined and the potential correlation of beta-catenin alteration with invasion was elucidated. Membranous beta-catenin was detected constantly in non-cancerous mucosa but became reduced or absent in cancer tissues. The cytoplasmic and nuclear accumulation of beta-catenin could be observed in premalignant (atrophic gastritis and intestinal metaplasia) and cancer tissues, particularly in those infiltrated into deep muscular region. beta-catenin mutation was not detected in all of tissue samples with and without translocalized beta-catenin. These results indicate that beta-catenin translocalization is a common phenomenon in gastric cancers as well as their related lesions. The loss of membranous and the gain of cytoplasmic and nuclear beta-catenin in gastric cancers checked in this study are not due to the mutational event. beta-catenin molecules translocalized in the nuclei are closely correlated with tumor invasion.

Cell Membrane↗
PubMed2004

[Progress in the treatment of stained teeth].

The treatment of stained teeth has been one of the striking aspects of stomatology and esthetic dentistry. Based on detailed data and references, this article introduces the types of stained teeth and the main treatment methods including strong point, weakness, limitation of the usage, result, and the relevant mechanisms. It addresses the researches on problems in the treatment of stained teeth. Also in this paper is envisaged what will be done to treat the stained teeth in future.

Dental Veneers↗
PubMed2004

Production of neutralizing monoclonal antibody against human vascular endothelial growth factor receptor II.

AIM: To prepare neutralizing monoclonal antibody (mAb) against extracellular immunoglobulin (Ig)-like domain III of vascular endothelial growth factor receptor KDR and study its biological activity. METHODS: Soluble KDR Ig domain III (KDR-III) fusion protein was expressed in E Coli and purified from the bacterial periplasmic extracts via an affinity chromatography. Monoclonal antibodies against KDR-III were prepared by hybridoma technique. ELISA and FACS analysis were used to identify its specificity. Immunoprecipitation and [3H]-thymidine incorporation assay were also used to detect the activity of anti-KDR mAb blocking the phosphorylation of KDR tyrosine kinase receptor and the influence on vascular endothelial growth factor-induced mitogenesis of human endothelial cells. RESULTS: A monoclonal antibody, Ycom1D3 (IgG1), was generated from a mouse immunized with the recombinant KDR-III protein. Ycom1D3 bound specifically to both the soluble KDR-III and the cell-surface expressed KDR. Ycom1D3 effectively blocked VEGF/KDR interaction and inhibited VEGF-stimulated KDR activation in human endothelial cells. Furthermore, the antibody efficiently neutralized VEGF-induced mitogenesis of human endothelial cells. CONCLUSION: Our results suggest that the anti-KDR mAb, Ycom1D3, has potential applications in the treatment of cancer and other diseases where pathological angiogenesis is involved.

Animals↗
PubMed2004

Frequent CYP1A1 expression in gastric cancers and their related lesions.

CYP1A1 expression in various tissues of 43 gastric cancer cases was analyzed with frozen tissue array-based immunohistochemical staining (IHC), RT-PCR, Western blot analysis and EROD (7-ethoxyresourfin-O-deethylase) assay. CYP1A1 was detected immunohistochemically in 86% (37/43) of gastric cancers, in both 57% (4/7) of atrophic gastritis and intestinal metaplasia and in 7.7% (1/13) of non-cancerous mucosa. RT-PCR and Western blot analysis revealed coincident results with that of IHC and ruled out possible concurrent CYP1A2 expression. EROD assay showed increased CYP1A1/1B1 activity in either cancer or premalignant tissues but not in non-cancerous ones. The frequencies of CYP1A1 expression are significantly different between non-cancerous and premalignant (P<0.025) or cancer groups (P<0.005), suggesting that CYP1A1 is expressed at relatively early stage of gastrocarcinogenesis and exerts its effects throughout the stepwise oncogenic processes.

Biomarkers, Tumor↗
PubMed2004

[Analysis of plasmid pUDKH by anion-exchange high performance liquid chromatogaphy].

pUDKH, a new plasmid DNA comprising human hepatocyte growth factor (HGF), was developed as a potential genetherapeutic product for peripheral arterial disease. An anion-exchange high performance liquid chromatographic (HPLC) method was developed to determine the proportion of plasmid DNA in both opened and supercoiled forms. A TSK gel DNA-NPR column was equilibrated with 50% buffer A (20 mmol/L Tris-HCl, pH 8.8) and 50% buffer B (buffer A with 1 mol/L NaCl added). pUDKH was analyzed by using a gradient HPLC with a mobile phase from 50% B to 80% B and with a UV detection at 260 nm. The flow rate was 0.5 mL/min. The method was also used to monitor the production procedures.

Chromatography, High Pressure Liquid↗
PubMed2004

[Construction and expression of single chain Fv gene against domain II of human VEGF receptor II].

The genes encoding for the light and heavy chain variable regions (V(H) and V(L)) has been cloned by RT-PCR from a murine hybridoma that produced monoclonal antibody (mAb) Ycom1D3, which was against domain III of human vascular endothelial growth factor receptor II (KDRIII) and were then connected to each other by a short peptide linker containing 15 amino acids (Gly4Ser)3 using splice-overlap extensive PCR. The recombinant Ycom1D3-ScFv gene was cloned into the expression vector pAYZ and induced to express in E. coli 16C9. SDS-PAGE and Western blot analysis showed that the recombinant Ycom1D3-ScFv gene was expressed in E. coli 16C9 and the relative molecular weight of the fusion protein is 30kD which was consistent with the theoretically predicted value. ScFv expression was in the form of an inclusion body and the purified fusion protein was obtained after a series of purification steps including cell breakage, inclusion body solubilization, TALON metal affinity chromatography and protein refolding. Flow cytometric analysis showed that the ScFv fragment can react with human umbilical vein endothelial cells (HUVECs) which express KDR on the cell surface. In Conclusion, Recombinant Ycom1D3-ScFv gene has been successfully constructed and expressed in E. coli 16C9, which could be useful in both diagnostic and therapeutic applications.

Animals↗
PubMed2003

Resveratrol promotes differentiation and induces Fas-independent apoptosis of human medulloblastoma cells.

Resveratrol has tumor-suppressive activities in some in vitro and in vivo experimental systems but its effect on medulloblastoma cells is still unknown. In this study, resveratrol was used to treat four human medulloblastoma cell lines (Med-3, UW228-1, -2 and -3) and its effects on cell growth, differentiation and death were examined by multiple approaches. Expression of Fas, FasL and caspase-3 in the cells without and with resveratrol treatments was examined by immunocytochemical staining and mRNA in situ hybridization and the influence of anti-Fas antibody (200 ng/ml) in cell growth and survival was determined as well. The results demonstrated that resveratrol could suppress growth, promote differentiation and commit its target cells to apoptosis in time- and dose-related fashions. Fas was constitutively expressed but FasL was undetectable in the four lines in spite of resveratrol treatment. Anti-Fas antibody (200 ng/ml) neither inhibited growth nor induced apoptosis of those cell lines. Up-regulated caspase-3 was found in resveratrol-treated populations and appearance of its cleaved form was closely associated with the apoptotic event. These findings suggest for the first time that resveratrol is an effective anti-medulloblastoma agent that kills medulloblastoma cells through a Fas-independent pathway.

Antineoplastic Agents, Phytogenic↗
PubMed2003

Structure-based design, synthesis, and biological evaluation of irreversible human rhinovirus 3C protease inhibitors. 8. Pharmacological optimization of orally bioavailable 2-pyridone-containing peptidomimetics.

The optimization of the pharmacokinetic performance of various 2-pyridone-containing human rhinovirus (HRV) 3C protease (3CP) inhibitors following oral administration to either beagle dogs or CM-monkeys is described. The molecules described in this work are composed of a 2-pyridone-containing peptidomimetic binding determinant and an alpha,beta-unsaturated ester Michael acceptor moiety which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. Modification of the ester contained within these compounds is detailed along with alteration of the P(2) substituent present in the peptidomimetic portion of the inhibitors. The pharmacokinetics of several inhibitors in both dogs and monkeys are described (7 h plasma concentrations after oral administration) along with their human plasma stabilities, stabilities in incubations with human, dog, and monkey microsomes and hepatocytes, Caco-2 permeabilities, and aqueous solubilities. Compounds containing an alpha,beta-unsaturated ethyl ester fragment and either an ethyl or propargyl P(2) moiety displayed the most promising combination of 3C enzyme inhibition (k(obs)/[I] 170 000-223 000 M(-1) s(-1)), antiviral activity (EC(50) = 0.047-0.058 microM, mean vs seven HRV serotypes), and pharmacokinetics following oral administration (7 h dog plasma levels = 0.248-0.682 microM; 7 h CM-monkey plasma levels = 0.057-0.896 microM).

3C Viral Proteases↗
PubMed2003

The complete genome sequence of the Arabidopsis and tomato pathogen Pseudomonas syringae pv. tomato DC3000.

We report the complete genome sequence of the model bacterial pathogen Pseudomonas syringae pathovar tomato DC3000 (DC3000), which is pathogenic on tomato and Arabidopsis thaliana. The DC3000 genome (6.5 megabases) contains a circular chromosome and two plasmids, which collectively encode 5,763 ORFs. We identified 298 established and putative virulence genes, including several clusters of genes encoding 31 confirmed and 19 predicted type III secretion system effector proteins. Many of the virulence genes were members of paralogous families and also were proximal to mobile elements, which collectively comprise 7% of the DC3000 genome. The bacterium possesses a large repertoire of transporters for the acquisition of nutrients, particularly sugars, as well as genes implicated in attachment to plant surfaces. Over 12% of the genes are dedicated to regulation, which may reflect the need for rapid adaptation to the diverse environments encountered during epiphytic growth and pathogenesis. Comparative analyses confirmed a high degree of similarity with two sequenced pseudomonads, Pseudomonas putida and Pseudomonas aeruginosa, yet revealed 1,159 genes unique to DC3000, of which 811 lack a known function.

Arabidopsis↗
PubMed2003

Gene RB cloned from Solanum bulbocastanum confers broad spectrum resistance to potato late blight.

Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating potato disease in the world. Control of late blight in the United States and other developed countries relies extensively on fungicide application. We previously demonstrated that the wild diploid potato species Solanum bulbocastanum is highly resistant to all known races of P. infestans. Potato germplasm derived from S. bulbocastanum has shown durable and effective resistance in the field. Here we report the cloning of the major resistance gene RB in S. bulbocastanum by using a map-based approach in combination with a long-range (LR)-PCR strategy. A cluster of four resistance genes of the CC-NBS-LRR (coiled coil-nucleotide binding site-Leu-rich repeat) class was found within the genetically mapped RB region. Transgenic plants containing a LR-PCR product of one of these four genes displayed broad spectrum late blight resistance. The cloned RB gene provides a new resource for developing late blight-resistant potato varieties. Our results also demonstrate that LR-PCR is a valuable approach to isolate genes that cannot be maintained in the bacterial artificial chromosome system.

Amino Acid Sequence↗
PubMed2003

Distinctive patterns of gene expression in premalignant gastric mucosa and gastric cancer.

Current epidemiological evidence supports a pathogenetic model of gastric cancer involving intermediate stages that include chronic gastritis and intestinal metaplasia. This study explores the molecular features of gastric cancer and premalignant stages using DNA microarray-based gene expression profiling and relates these findings to clinical, pathological, and ethnic parameters. A total of 124 tumor and adjacent mucosa samples were analyzed using spotted cDNA microarrays containing 9381 nonredundant gene elements. Tumor specimens were diffuse, intestinal, or mixed gastric cancer and adjacent mucosa, which generally displayed signs of chronic gastritis or intestinal metaplasia. Expression patterns could be discerned that readily defined premalignant and tumor subtypes. Chronic gastritis exhibits a pronounced mitochondrial gene expression signature, which may be linked to Helicobacter pylori pathogenesis. Intestinal metaplasia was associated with increased expression of many intestinal differentiation genes, many of which were not overexpressed in tumors. Samples were obtained from 91 Australian and 33 Chinese patients to explore potential variation in gene expression between these populations. Despite differences in the incidence, and potentially the etiology, of gastric cancer between these ethnic groups, we found the tumors to be molecularly similar. The identification of molecular signatures that are characteristic of subtypes of gastric cancer and associated premalignant changes should enable further analysis of the steps involved in the initiation and progression of this disease.

Adult↗
PubMed2003

A formal [3 + 3] cycloaddition reaction. Improved reactivity using alpha,beta-unsaturated iminium salts and evidence for reversibility of 6pi-electron electrocyclic ring closure of 1-oxatrienes.

A detailed account regarding a formal [3 + 3] cycloaddition method using 4-hydroxy-2-pyrones and 1,3-diketones is described here. This formal cycloaddition reaction or annulation reaction is synthetically useful for constructing 2H-pyranyl heterocycles. The usage of alpha,beta-unsaturated iminium salts is significant in controlling competing reaction pathways to give exclusively 2H-pyrans. Most significantly, experimental evidence is provided to support the mechanism of this reaction that involves a sequential Knoevenagel condensation and a reversible 6pi-electron electrocyclic ring-closure of 1-oxatrienes.

Alkenes↗
PubMed2003

The TIGR rice genome annotation resource: annotating the rice genome and creating resources for plant biologists.

Rice is not only a major food staple for the world's population but it also is a model species for a major group of flowering plants, the monocotyledonous plants. Draft genomic sequence of two subspecies of rice, Oryza sativa spp. japonica and indica ssp. are publicly available. To provide the community with a resource to data-mine the rice genome, we have constructed an annotation resource for rice (http://www.tigr.org/tdb/e2k1/osa1/). In this resource, we have annotated the rice genome for gene content, identified motifs/domains within the predicted genes, constructed a rice repeat database, identified related sequences in other plant species, and identified syntenic sequences between rice and maize. All of the data is available through web-based interfaces, FTP downloads, and a Distributed Annotation System.

Chromosomes, Artificial↗
PubMed2003

Molecular and cytological analyses of large tracks of centromeric DNA reveal the structure and evolutionary dynamics of maize centromeres.

We sequenced two maize bacterial artificial chromosome (BAC) clones anchored by the centromere-specific satellite repeat CentC. The two BACs, consisting of approximately 200 kb of cytologically defined centromeric DNA, are composed exclusively of satellite sequences and retrotransposons that can be classified as centromere specific or noncentromere specific on the basis of their distribution in the maize genome. Sequence analysis suggests that the original maize sequences were composed of CentC arrays that were expanded by retrotransposon invasions. Seven centromere-specific retrotransposons of maize (CRM) were found in BAC 16H10. The CRM elements inserted randomly into either CentC monomers or other retrotransposons. Sequence comparisons of the long terminal repeats (LTRs) of individual CRM elements indicated that these elements transposed within the last 1.22 million years. We observed that all of the previously reported centromere-specific retrotransposons in rice and barley, which belong to the same family as the CRM elements, also recently transposed with the oldest element having transposed approximately 3.8 million years ago. Highly conserved sequence motifs were found in the LTRs of the centromere-specific retrotransposons in the grass species, suggesting that the LTRs may be important for the centromere specificity of this retrotransposon family.

Base Sequence↗
PubMed2003

Apoptosis of bladder cancer cells induced by short-term and low-dose Mitomycin-C: potential molecular mechanism and clinical implication.

Adjuvant chemotherapies have been used to prevent recurrence of bladder transitional cell carcinoma (TCC), but their efficacies are variable due to the side effects of anti-cancer agents and the drug resistant property of the target cells. To provide experimental evidence for improving clinical management of TCCs, two human TCC cell lines, EJ and BIU, were treated for 1 or 2 h by 50, 100, 150 and 200 micro g/ml, respectively and their growth and death patterns were elucidated in 12-h intervals. The status of Fas, FasL and caspase-3 in the two cell lines were analyzed with immunocytochemical staining and Western blot hybridization, and their potential link to MMC-induced cell death was investigated by treating the cells with anti-Fas antibody (150 ng/ml) and by incubating the cells with an inhibitor of caspase-3 related proteases Ac-DEVO-CHO (250 micro M) 1 h before 100 micro g/ml MMC treatment. The results demonstrated that the lower dose (100 micro g/ml) and short-term (1 h) MMC treatment could induce sufficient apoptosis in EJ and BIU populations within 48 or 60 h. Constitutive soluble and membrane Fas and FasL were found in both cell lines, and caspase-3 could be upregulated after MMC treatment. Anti-Fas antibody could commit the target cells to die of apoptosis, while Ac-DEVD-CHO inhibited MMC-induced apoptosis. Our data thus suggest that MMC-induced apoptosis in EJ and BIU cells is mediated by Fas and upregulation and activation of caspase-3 is an essential element for the apoptotic process. Reduced dose and short-term MMC strategy would be of practical value either in determining the apoptotic susceptibility of individual TCC cases or in the clinical instillation of urothelial cancers.

Antibiotics, Antineoplastic↗