Biomedical subjects

Jianping Chen

Publications and source records attributed to Jianping Chen.

At least 19 recordsLinked to original sources

PubMed2006

Antitumor activity of HER1/EGFR tyrosine kinase inhibitor erlotinib, alone and in combination with CPT-11 (irinotecan) in human colorectal cancer xenograft models.

Erlotinib (Tarceva, OSI-774) is a potent, orally available, small-molecule inhibitor of HER1/EGFR tyrosine-kinase activity. In this study, the antitumor activity of erlotinib was evaluated in two human colorectal tumor xenograft models (LoVo and HCT116) in athymic mice. When erlotinib was administered as monotherapy, significant tumor growth inhibition (TGI) was seen in the LoVo model at both 100 mg/kg [TGI > 100%, P < 0.001; 6/10 partial regressions (PRs)] and 25 mg/kg (TGI = 79%, P < 0.001) doses. However, the HCT116 xenograft model was not responsive to any dose of erlotinib tested. The differential response to erlotinib of these two tumor models was not a result of differences in HER1/EGFR expression levels since these were similar in both cell lines. However, it was demonstrated that resistance to erlotinib in the HCT116 model may be a result of persistent activation of ERK in these tumors. Based on the single agent activity of erlotinib in LoVo tumors, a combination study with CPT-11 (Camptosar, irinotecan) was performed. CPT-11 at the optimal dose of 60 mg/kg or a lower dose of 15 mg/kg resulted in significant TGI (TGI > 100%, P < 0.001, and TGI = 93%, P < 0.001, respectively) in LoVo-bearing mice. Combination treatment with erlotinib (25 mg/kg) and CPT-11 (15 mg/kg) produced significantly greater antitumor activity (TGI > 100%, P < 0.001; 10/10 PRs) than either agent alone (P < 0.05), with no increase in toxicity. These data indicate that erlotinib can enhance the antitumor activity of CPT-11, without enhanced toxicity, in the LoVo human colorectal tumor xenograft model.

Animals↗

PubMed2006

Synthesis, properties, and biological activity of poly[di(sodium carboxylatoethylphenoxy)phosphazene].

A new water-soluble polyphosphazene polyelectrolyte containing carboxylate functionalities, poly[di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP) was synthesized via reaction of macromolecular substitution. The polymer was characterized using (1)H, (31)P NMR, and gel permeation chromatography with multiangle laser light scattering detection. PCEP was shown to undergo hydrolytic degradation in aqueous solutions, as indicated by the decrease in the molecular weight and the release of side groups. A series of incompletely substituted copolymers of PCEP containing varying amounts of residual chlorine atoms was also prepared. The rate of degradation for such copolymers increased with the rise in the content of chlorine atoms. In vivo studies demonstrated high potency of PCEP as a vaccine immunoadjuvant. The new polyphosphazene was also shown to be capable of forming microspheres in aqueous solutions via reactions of ionic complexation with physiologically occurring amines, such as spermine.

Adjuvants, Immunologic↗

PubMed2006

Recovery of infectious rabbit hemorrhagic disease virus from rabbits after direct inoculation with in vitro-transcribed RNA.

We report the first full-length infectious clone of strain JX/CHA/97 of rabbit hemorrhagic disease virus (RHDV). The transcripts from the full-length cDNA clones were infectious when they were directly injected into rabbits. The sequence of the virus recovered from the rabbits was identical to that of the injected RNA transcripts. The cDNA clone was engineered to contain one silent nucleotide change to create an EcoRV site (A to T at nucleotide 2908). The genetic marker was retained in the recovered progeny virus. The transfection of RNA transcripts into RK-13 cells resulted in the synthesis of viral antigens, indicating that the cDNA clones were replication competent. This stable infectious molecular clone should be an important tool for developing a better understanding of the molecular biology and pathogenesis of RHDV.

Animals↗

PubMed2006

[Cloning of major outer membrane protein gene of Legionella pneumophila and detection of its expression in prokaryotic cell].

In this study, the ompS gene, a major outer membrane protein gene of Legionella pneumophila, was obtained from the DNA of Legionella pneumophila by PCR. The gene was cloned into prokaryotic expressional plasmid pUC18 to construct recombinant plasmid. The recombinant plasmid was transformed into E. coli strain BL21. The identification was made by means of restriction enzyme analysis, polymerase chain reaction, DNA sequencing analysis, SDS--polyacrylamine gel electrophoresis analysis and Western blot. The results showed that the ompS gene of 914 bp was amplified from Legionella pneumophila DNA, the recombinant plasmid pLPompS was constructed and its expression in prokaryotic cell was detected successfully.

Amino Acid Sequence↗

PubMed2006

[Cloning the lvgA gene of Legionella pneumophila and detecting its expression in Escherichia coli].

In order to clone lvgA gene (Legionella virulence gene) of Legionella pneumophila and detect its expression in prokaryotic cell, we amplified the lvgA gene from the total cell DNA of Legionella pneumophila with PCR,and then inserted it into the coloning vector pUC18. The recombinant plasmid pUlvgA was obtained. After the recombinant plasmid pUlvgA was identified with restriction enzyme analysis, polymerase chain reaction and nucleotide sequencing analysis, the lvgA gene was subcloned into the prokaryotic expression vector pGEX-4T-1. The prokaryotic expression recombinant plasmid pGlvgA was constructed. After IPTG induction, the E. coli JM109 containing the recombinant plasmid pGlvgA expressed fusion protein. The expression of lvgA was subsequently detected by SDS-polyacrylamine gel electrophoresis and Western-blot analysis. The results indicated that the lvgA gene of 627 bp long was amplified, the recombinant plasmids pUlvgA and pGlvgA were constructed successfully, and the GST-LvgA fusion protein of approximately 36 KDa in size was expressed in prokaryotic cell efficiently as expected.

Bacterial Proteins↗

PubMed2005

High degree of inter-clade cross-reactivity of HIV-1-specific T cell responses at the single peptide level.

OBJECTIVES: To determine HIV-1-specific T cell responses in clade B infected individuals recognizing the clade A, B and C consensus sequences in order to assess the degree of inter-clade cross-reactivity of these immune responses at the single epitope level. METHODS: HIV-1-specific T cell responses were assessed cross-sectionally in 27 chronically HIV-1-infected individuals from a population infected mainly with clade B viral strains, using an interferon-gamma Elispot assay with a total of 1230 overlapping peptides spanning the entire amino acid sequence of the clade A, B and C 2001 consensus sequences. RESULTS: No significant difference was observed between the total magnitude or breadth of T cell responses recognizing either the clade A, B or C consensus sequences. However, at the single peptide level, 194 T cell responses were identified that recognized only one of the three different clade-specific peptide variants (A: B: C, 34: 105: 55), 125 T cell responses recognized two of the three peptide variants (AB: AC: BC, 71: 15: 39) and 166 T cell responses (34%) were cross-reactive with all three different peptide variants. Peptides recognized in all three consensus sequence variants had a significantly lower entropy (P < 0.0001) and a significantly higher inter-clade homology (P < 0.0001). CONCLUSIONS: Viral epitopes within regions of low HIV-1 clade B diversity and high inter-clade homology can be recognized in the clade A, B and C variants and indicate a wide degree of cross-isolate and cross-clade recognition by HIV-1-specific T cells. These regions may therefore be of particular relevance for the design of HIV-1 vaccines.

Adult↗

PubMed2005

HIV incidence and factors contributed to retention in a 12-month follow-up study of injection drug users in Sichuan Province, China.

HIV-1 seroconversion and subtype were evaluated, and factors associated with cohort retention were analyzed for subjects' baseline sociodemographic and behavioral characteristics in a 12-month follow-up study of injection drug users (IDUs). In November 2002, a community-based baseline survey was conducted to recruit 333 HIV-seronegative IDUs for a prospective cohort study in Xichang County of Sichuan Province, China. During the 12-month follow-up period, HIV incidence was 3.17 per 100 person-years (95% confidence interval [CI]: 0.98, 5.37), and all subtypes of 8 HIV-1 seroconversions were CRF_07BC. The retention rate at the 12-month follow-up visit was 70.3% (234 of 333 subjects). In a multiple logistic regression model, ethnicity (OR = 0.60, 95% CI: 0.34, 1.04) and appearing at the 6-month follow-up visit (OR = 9.03, 95% CI: 5.14, 15.89) were independently associated with retention. No drug-using or sexual behaviors were found to be associated with retention. This study confirmed one of drug-trafficking routes in mainland China, from Yunnan to Sichuan and then to Xinjiang. This study also suggested that HIV is spreading rapidly to more geographic areas along drug-trafficking routes in China, and a short-term follow-up rate may predict a long-term retention rate in this IDU cohort.

Adult↗

PubMed2005

Biochemical and HIV-1 coreceptor properties of K26R, a new CCR5 Variant in China's Sichuan population.

Despite multiple exposures to HIV-1, some individuals remain uninfected. This resistance to HIV infection has been associated with homozygosity for a 32-basepair deletion in the CCR5 receptor gene. This variant is frequent in caucasians but extremely rare in Asians and Africans. Identifying variations in the CCR5 gene that affect susceptibility to HIV infection in non-caucasians is therefore of great interest. In this report, we identify 5 CCR5 coding region variants in a Chinese population. The K26R mutation is an undescribed gene variant, whereas 228delK was already found in caucasians and G106R, C178R, and R223Q were previously described in Asian populations and functionally analyzed. As the function of K26R was still unknown, we focused our work on studying its chemokine receptor activity and HIV coreceptor properties compared with wild-type CCR5 and G106R, an already analyzed mutant taken as another control. We observed that K26R displayed alteration in MIP1-beta/CCL4 and RANTES/CCL5 ligand binding and exhibited a slightly decrease for HIV coreceptor properties.

Acquired Immunodeficiency Syndrome↗

PubMed2005

[Cloning and sequence analysis of ITS gene of Leishmania donovani isolates from different epidemic foci in China].

This study was directed to determine the nucleotide sequence of the ITS (internal transcribed spacer) gene of Leishmania donovani isolates from desert foci (L. d XJ771), hill foci (L. d SC10) and plain foci (L. d SD2), and to find out the differences of the sequences of ITS gene among these three isolates. The specific ITS fragments from nuclear DNA of three Leishmania isolates were amplified by PCR, cloned into PMD18-T vector, and then sequenced by the dideoxy chain termination method. Sequence analysis showed that the amplified DNA fragments of the three isolates were 1 086 bp (L. d XJ771), 1 027 bp (L. d SC10) and 1 028 bp (L. d SD2). There were obvious sequence differences among L. d XJ771, L. d SC10 and L. d SD2. The differences between L. d XJ771 (desert foci isolate) and L. d SC10 (hill foci isolate) were less than the differences between L. d XJ771 (desert foci isolate ) and L. d SD2. (plain foci isolate).

China↗

PubMed2004

Community-based survey of HIV transmission modes among intravenous drug users in Sichuan, China.

GOAL: The goal of this study was to investigate the prevalence and different transmission risk factors of HIV among intravenous drug users (IDUs) in the Liangshan Yizu Autonomous Region of Sichuan province, China. METHODS: From November 8, 2002, to November 29, 2002, a community-based survey was conducted to investigate demographic characteristics, sharing patterns of injection equipment, frequencies of injection equipment, and sexual behaviors in IDUs. Blood samples were also collected to test for HIV and syphilis infection. A total of 379 subjects were recruited for the study through community outreach and peer recruiting methods. RESULTS: Of 379 IDUs, HIV prevalence was 11.3% (43 of 379). Ethnicity, total times of shared injection equipment in the past 3 months, shared cotton in the past 3 months, and syphilis infection were associated with HIV infection after univariate analysis using the chi-squared test. Multivariate logistic regression analysis showed total times of sharing injection equipment in the past 3 months (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.18-4.43) and syphilis infection (OR, 3.10; 95% CI, 1.48-6.48) in the final model were independently associated with HIV prevalence. CONCLUSION: The results of this study suggested total times of sharing injection equipment in the past 3 months and syphilis infection were significantly associated with HIV infection. Further seroepidemiologic prospective cohort studies should be conducted to clarify the impact of syphilis and high-risk sexual behaviors on HIV transmission through unprotected sexual intercourse.

Adolescent↗

PubMed2004

Simple subtyping assay for human immunodeficiency virus type 1 subtypes B, C, CRF01-AE, CRF07-BC, and CRF08-BC.

After the initial development of a human immunodeficiency virus type 1 (HIV-1) subtype-screening tool by nested multiplex PCR, we further improve it through the redesign of subtype-specific primers based on subtype signature pattern (SSP) analyses and optimization of the PCR conditions. Extracted RNA from plasma samples was used in reverse transcription and the cDNA products were added to the first round PCR, in which universal primers in the gag region were used to detect HIV-1 M group isolates. In the second round of PCR, three pairs of subtype-specific primers, detecting subtypes B, C, and CRF01-AE, were added in one tube. Subtype determination was based on the different size of PCR products on the agarose gel electrophoresis. An additional set of primers detecting only the prevalent recombinant strains CRF07-BC and CRF08-BC was used to discriminate CRF07- and CRF08-BC from pure subtype C. Testing for all kinds of HIV subtype reference strains indicated that this assay was applicable. A panel of 252 HIV-positive samples and 30 HIV-negative samples was further used to evaluate and validate this assay. Compared to the assay of sequence-based phylogenetic analysis, the newly developed assay has an adequate designated subtype sensitivity, 93.2% (69 of 74) for subtype B, 95.1% (117 of 123) for subtype C, 94.0% (47 of 50) for CRF01-AE, and 95.0% (115 of 121) for CRF07-BC and CRF08-BC. Most importantly, the intersubtype specificity of the assay was found to be 100%. The assay specificity was also found to be 100% when used to test 30 HIV-negative samples. The average reproducibility was 96.0% for subtype B, 96.7% for subtype C, and 95.0% for CRF01-AE. We have developed a simple, rapid, and low cost assay for screening subtypes B, C, CRF01-AE, CRF07-BC, and CRF08-BC in China.

Acquired Immunodeficiency Syndrome↗

PubMed2004

[Cloning and expression of immunoadjuvant molecule--CTB gene].

We cloned cholera toxin subunit B gene from 569B and M045 strain of Vibrio cholerae with polymerase chain reaction, constructed recombinant plasmid pCTB, and transformed pCTB into the prokaryotic cell strain JM109. The indentification was made by means of restriction enzyme analysis, polymerase chain reaction, DNA sequencing, SDS-polyacrylamine gel electrophoresis analysis and Western blot. The results indicate that we have amplified cholera toxin subunit B gene of 376 bp from Vibrio cholerae and hve constructed the recombinant plasmid pCTB, and we have affained the object amied at successful expression of 12 KD in the prokaryotic cell strain.

Adjuvants, Immunologic↗

PubMed2003

Leaves of the Lamiaceae species Glechoma hederacea (ground ivy) contain a lectin that is structurally and evolutionary related to the legume lectins.

A novel lectin has been isolated and cloned from leaves of Glechoma hederacea (ground ivy), a typical representative of the plant family Lamiaceae. Biochemical analyses indicated that the G. hederacea agglutinin (Gleheda) is a tetrameric protein consisting of four subunits pairwise linked through an interchain disulphide bridge and exhibits a preferential specificity towards N-acetylgalactosamine. Cloning of the corresponding gene and molecular modeling of the deduced sequence demonstrated that Gleheda shares high sequence similarity with the legume lectins and exhibits the same overall fold and three-dimensional structure as the classical legume lectins. The identification of a soluble and active legume lectin ortholog in G. hederacea not only indicates that the yet unclassified Lamiaceae lectins belong to the same lectin family as the legume lectins, but also sheds a new light on the specificity, physiological role and evolution of the classical legume lectins.

Amino Acid Sequence↗

PubMed2003

[Protective effect of ganmeiling injection on chronic hepatic injury in rats].

OBJECTIVE: To study protective effect of Injection Ganmeiling on chronic hepatic injury. METHODS: The activity of AST, ALT and ALP in serum and histopathological change were determined in hepatic injury rats induced by CCl4. RESULTS: Ganmeiling obviously inhibited the rising of AST, ALT and ALP in serum. The histopathological examination showed that Ganmeiling could alleviate the condition of necrosis and the degeneration of hepatic cells. CONCLUSION: The results suggested that Ganmeiling could protect liver from hepatic injury induced by CCl4.

Animals↗

PubMed2003

Using a cDNA microarray to study cellular gene expression altered by Mycobacterium tuberculosis.

OBJECTIVE: To examine the global effects of Mycobacterium tuberculosis (M. tuberculosis) infection on macrophages. METHODS: The gene expression profiling of macrophage U937, in response to infection with M. tuberculosis H(37)R(a), was monitored using a high-density cDNA microarray. RESULTS: M. tuberculosis infection caused 463 differentially expressed genes, of which 366 genes are known genes registered in the Gene Bank. These genes function in various cellular processes including intracellular signalling, cytoskeletal rearrangement, apoptosis, transcriptional regulation, cell surface receptors, cell-mediated immunity as well as a variety of cellular metabolic pathways, and may play key roles in M. tuberculosis infection and intracellular survival. CONCLUSIONS: M. tuberculosis infection alters the expression of host-cell genes, and these genes will provide a foundation for understanding the infection process of M. tuberculosis. The cDNA microarray is a powerful tool for studying pathogen-host cell interaction.

Cells, Cultured↗

PubMed2003

[Complete sequence analysis on potato virus M infecting Solanum muricatum].

The complete sequence of Potato virus M from Solanum muricatum was determined. The liner, single-strand and positive sense genomic RNA was 8526 nucleotides long and six open reading frames were identified. The genome organization was typical feature of genus Carlavirus. Sequence analysis showed that PVM isolates shared 62.5% - 97.2% nucleotide and 60.9% - 97.4% amino acid identities. The coat protein gene was most conserved and TGB3 gene was greatly variable. Phylogenetic tree analysis suggested that the Idaho potato isolate (PVM-Id) was a distant strain, and other 4 isolates were grouped discriminatively based on CP and NABP amino acid sequences respectively. This is the first report of PVM from Solanum muricatum.

Capsid Proteins↗

PubMed2002

Characterisation of potyviruses from sugarcane and maize in China.

Sugarcane or maize leaves with mosaic virus symptoms were collected from 13 sites in China. Sequence data showed that all 8 samples from maize contained Sugarcane mosaic virus (SCMV); complete sequences were determined from 2 samples and partial sequences (the CI coding region and the 3'-part of the genome) from the others. The 5 sugarcane samples all contained a virus tentatively described as Sorghum mosaic virus (SrMV) and in three of them SCMV was also detected; 2 SrMV sequences and the 3 SCMV ones were completely determined and partial SrMV sequences were obtained from the remaining 3 samples. The features of the complete sequences of SCMV and SrMV are described for the first time. Sequence comparisons and phylogenetic analysis showed three distinct groups of Chinese SCMV sequences (sugarcane isolates from Zhejiang province, a maize isolate from Guangdong and maize isolates from other provinces). The SrMV sequences were similar to one another (> 93% identical nucleotides); they resembled published sequences in the coat protein but were less similar in the 3'-UTR. The complete sequences of SCMV and SrMV had about 70% nucleotides identical to one another and to Maize dwarf mosaic virus (MDMV). MDMV was not detected in any of the samples.

China↗

PubMed2002

Bean common mosaic virus isolates causing different symptoms in asparagus bean in China differ greatly in the 5'-parts of their genomes.

Potyvirus isolates from asparagus bean ( Vigna sesquipedalis) plants in Zhejiang province, China, caused either rugose and vein banding mosaic symptoms (isolate R) or severe yellowing (isolate Y) in this host, but were otherwise similar in host range. Both isolates were completely sequenced and shown to be isolates of Bean common mosaic virus (BCMV). The complete sequences were 9992 (R) or 10062 (Y) nucleotides long and shared 91.7% identical nucleotides (93.2% identical amino acids) in their genomes and were more distantly related to the BCMV-Peanut stripe virus sequence (PStV). The isolates were much less similar to one another in the 5'-UTR and the N-terminal region of the P1 protein. In the P1, isolate Y was closer to PStV (76.1% identical amino acids) than to isolate R (64.8%). Phylogenetic analyses of the coat protein region showed that the new isolates grouped with other isolates from Vigna spp., forming the blackeye cowpea mosaic strain subgroup of BCMV with 94-98% nucleotides (96-99% amino acids) identical to one another and about 90% identity to other BCMV isolates. Other significant subgroupings amongst published BCMV isolates were detected.

5' Untranslated Regions↗